[Federal Register Volume 80, Number 133 (Monday, July 13, 2015)]
[Proposed Rules]
[Pages 40138-40765]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-15500]



[[Page 40137]]

Vol. 80

Monday,

No. 133

July 13, 2015

Part II





Environmental Protection Agency





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40 CFR Parts 9, 22, 85, et al.





Department of Transportation





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National Highway Traffic Safety Administration





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49 CFR Parts 512, 523, 534, et al.





Greenhouse Gas Emissions and Fuel Efficiency Standards for Medium- and 
Heavy-Duty Engines and Vehicles--Phase 2; Proposed Rule

Federal Register / Vol. 80 , No. 133 / Monday, July 13, 2015 / 
Proposed Rules

[[Page 40138]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 9, 22, 85, 86, 600, 1033, 1036, 1037, 1039, 1042, 
1043, 1065, 1066, and 1068

DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 512, 523, 534, 535, 537, and 538

[EPA-HQ-OAR-2014-0827; NHTSA-2014-0132; FRL-9927-21-OAR]
RIN 2060-AS16; RIN 2127-AL52


Greenhouse Gas Emissions and Fuel Efficiency Standards for 
Medium- and Heavy-Duty Engines and Vehicles--Phase 2

AGENCY: Environmental Protection Agency (EPA) and Department of 
Transportation (DOT) National Highway Traffic Safety Administration 
(NHTSA)

ACTION: Proposed rule.

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SUMMARY: EPA and NHTSA, on behalf of the Department of Transportation, 
are each proposing rules to establish a comprehensive Phase 2 Heavy-
Duty (HD) National Program that will reduce greenhouse gas (GHG) 
emissions and fuel consumption for new on-road heavy-duty vehicles. 
This technology-advancing program would phase in over the long-term, 
beginning in the 2018 model year and culminating in standards for model 
year 2027, responding to the President's directive on February 18, 
2014, to develop new standards that will take us well into the next 
decade. NHTSA's proposed fuel consumption standards and EPA's proposed 
carbon dioxide (CO2) emission standards are tailored to each 
of four regulatory categories of heavy-duty vehicles: Combination 
tractors; trailers used in combination with those tractors; heavy-duty 
pickup trucks and vans; and vocational vehicles. The proposal also 
includes separate standards for the engines that power combination 
tractors and vocational vehicles. Certain proposed requirements for 
control of GHG emissions are exclusive to EPA programs. These include 
EPA's proposed hydrofluorocarbon standards to control leakage from air 
conditioning systems in vocational vehicles, and EPA's proposed nitrous 
oxide (N2O) and methane (CH4) standards for 
heavy-duty engines. Additionally, NHTSA is addressing misalignment in 
the Phase 1 standards between EPA and NHTSA to ensure there are no 
differences in compliance standards between the agencies. In an effort 
to promote efficiency, the agencies are also proposing to amend their 
rules to modify reporting requirements, such as the method by which 
manufacturers submit pre-model, mid-model, and supplemental reports. 
EPA's proposed HD Phase 2 GHG emission standards are authorized under 
the Clean Air Act and NHTSA's proposed HD Phase 2 fuel consumption 
standards authorized under the Energy Independence and Security Act of 
2007. These standards would begin with model year 2018 for trailers 
under EPA standards and 2021 for all of the other heavy-duty vehicle 
and engine categories. The agencies estimate that the combined 
standards would reduce CO2 emissions by approximately 1 
billion metric tons and save 1.8 billion barrels of oil over the life 
of vehicles and engines sold during the Phase 2 program, providing over 
$200 billion in net societal benefits. As noted, the proposal also 
includes certain EPA-specific provisions relating to control of 
emissions of pollutants other than GHGs. EPA is seeking comment on non-
GHG emission standards relating to the use of auxiliary power units 
installed in tractors. In addition, EPA is proposing to clarify the 
classification of natural gas engines and other gaseous-fueled heavy-
duty engines, and is proposing closed crankcase standards for emissions 
of all pollutants from natural gas heavy-duty engines. EPA is also 
proposing technical amendments to EPA rules that apply to emissions of 
non-GHG pollutants from light-duty motor vehicles, marine diesel 
engines, and other nonroad engines and equipment. Finally, EPA is 
proposing to require that rebuilt engines installed in new incomplete 
vehicles meet the emission standards applicable in the year of 
assembly, including all applicable standards for criteria pollutants.

DATES: Comments on all aspects of this proposal must be received on or 
before September 11, 2015. Under the Paperwork Reduction Act (PRA), 
comments on the information collection provisions are best assured of 
consideration if the Office of Management and Budget (OMB) receives a 
copy of your comments on or before August 12, 2015.
    EPA and NHTSA will announce the public hearing dates and locations 
for this proposal in a supplemental Federal Register document.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2014-0827 (for EPA's docket) and NHTSA-2014-0132 (for NHTSA's 
docket) by one of the following methods:
     Online: www.regulations.gov: Follow the on-line 
instructions for submitting comments.
     Email: [email protected].
     Mail:
    EPA: Air and Radiation Docket and Information Center, Environmental 
Protection Agency, Mail code: 28221T, 1200 Pennsylvania Ave. NW., 
Washington, DC 20460.
    NHTSA: Docket Management Facility, M-30, U.S. Department of 
Transportation, West Building, Ground Floor, Rm. W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery:
    EPA: EPA Docket Center, EPA WJC West Building, Room 3334, 1301 
Constitution Ave. NW., Washington, DC 20460. Such deliveries are only 
accepted during the Docket's normal hours of operation, and special 
arrangements should be made for deliveries of boxed information.
    NHTSA: West Building, Ground Floor, Rm. W12-140, 1200 New Jersey 
Avenue SE., Washington, DC 20590, between 9 a.m. and 4 p.m. Eastern 
Time, Monday through Friday, except Federal holidays.
    Instructions: EPA and NHTSA have established dockets for this 
action under Direct your comments to Docket ID No. EPA-HQ-OAR-2014-0827 
and/or NHTSA-2014-0132, respectively. See the SUPPLEMENTARY INFORMATION 
section on ``Public Participation'' for more information about 
submitting written comments.
    Docket: All documents in the docket are listed on the 
www.regulations.gov Web site. Although listed in the index, some 
information is not publicly available, e.g., confidential business 
information or other information whose disclosure is restricted by 
statute. Certain other material, such as copyrighted material, is not 
placed on the Internet and will be publicly available only in hard copy 
form. Publicly available docket materials are available either 
electronically through www.regulations.gov or in hard copy at the 
following locations:
    EPA: Air and Radiation Docket and Information Center, EPA Docket 
Center, EPA/DC, EPA WJC West Building, 1301 Constitution Ave. NW., Room 
3334, Washington, DC. The Public Reading Room is open from 8:30 a.m. to 
4:30 p.m., Monday through Friday, excluding legal holidays. The 
telephone number for the Public Reading Room is (202) 566-1744, and the 
telephone number for the Air Docket is (202) 566-1742.
    NHTSA: Docket Management Facility, M-30, U.S. Department of

[[Page 40139]]

Transportation, West Building, Ground Floor, Rm. W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590. The telephone number for the 
docket management facility is (202) 366-9324. The docket management 
facility is open between 9 a.m. and 5 p.m. Eastern Time, Monday through 
Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: EPA: For hearing information or to 
register, please contact: JoNell Iffland, Office of Transportation and 
Air Quality, Assessment and Standards Division (ASD), Environmental 
Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105; 
Telephone number: (734) 214-4454; Fax number: (734) 214-4816; Email 
address: [email protected]. For all other information related to 
the rule, please contact: Tad Wysor, Office of Transportation and Air 
Quality, Assessment and Standards Division (ASD), Environmental 
Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105; 
telephone number: (734) 214-4332; email address: [email protected].
    NHTSA: Ryan Hagen or Analiese Marchesseault, Office of Chief 
Counsel, National Highway Traffic Safety Administration, 1200 New 
Jersey Avenue SE., Washington, DC 20590. Telephone: (202) 366-2992; 
[email protected] or [email protected].

SUPPLEMENTARY INFORMATION: 

A. Does this action apply to me?

    This proposed action would affect companies that manufacture, sell, 
or import into the United States new heavy-duty engines and new Class 
2b through 8 trucks, including combination tractors, all types of 
buses, vocational vehicles including municipal, commercial, 
recreational vehicles, and commercial trailers as well as \3/4\-ton and 
1-ton pickup trucks and vans. The heavy-duty category incorporates all 
motor vehicles with a gross vehicle weight rating of 8,500 lbs or 
greater, and the engines that power them, except for medium-duty 
passenger vehicles already covered by the greenhouse gas standards and 
corporate average fuel economy standards issued for light-duty model 
year 2017-2025 vehicles. Proposed regulated categories and entities 
include the following:

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                                                 Examples of potentially
            Category             NAICS code \a\     affected entities
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Industry.......................          336111  Motor Vehicle
                                                  Manufacturers, Engine
                                                  Manufacturers, Truck
                                                  Manufacturers, Truck
                                                  Trailer Manufacturers.
                                         336112
                                         333618
                                         336120
                                         336212
Industry.......................          541514  Commercial Importers of
                                                  Vehicles and Vehicle
                                                  Components.
                                         811112
                                         811198
Industry.......................          336111  Alternative Fuel
                                                  Vehicle Converters.
                                         336112
                                         422720
                                         454312
                                         541514
                                         541690
                                         811198
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Note:\a\ North American Industry Classification System (NAICS).

This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely covered by these rules. 
This table lists the types of entities that the agencies are aware may 
be regulated by this action. Other types of entities not listed in the 
table could also be regulated. To determine whether your activities are 
regulated by this action, you should carefully examine the 
applicability criteria in the referenced regulations. You may direct 
questions regarding the applicability of this action to the persons 
listed in the preceding FOR FURTHER INFORMATION CONTACT section.

B. Public Participation

    EPA and NHTSA request comment on all aspects of this joint proposed 
rule. This section describes how you can participate in this process.

(1) How do I prepare and submit comments?

    In this joint proposal, there are many issues common to both EPA's 
and NHTSA's proposals. For the convenience of all parties, comments 
submitted to the EPA docket will be considered comments submitted to 
the NHTSA docket, and vice versa. An exception is that comments 
submitted to the NHTSA docket on NHTSA's Draft Environmental Impact 
Statement (EIS) will not be considered submitted to the EPA docket. 
Therefore, the public only needs to submit comments to either one of 
the two agency dockets, although they may submit comments to both if 
they so choose. Comments that are submitted for consideration by one 
agency should be identified as such, and comments that are submitted 
for consideration by both agencies should be identified as such. Absent 
such identification, each agency will exercise its best judgment to 
determine whether a comment is submitted on its proposal.
    Further instructions for submitting comments to either EPA or NHTSA 
docket are described below.
    EPA: Direct your comments to Docket ID No. EPA-HQ-OAR-2014-0827. 
EPA's policy is that all comments received will be included in the 
public docket without change and may be made available online at 
www.regulations.gov, including any personal information provided, 
unless the comment includes information claimed to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Do not submit information that you consider to 
be CBI or otherwise protected through www.regulations.gov or email. The 
www.regulations.gov Web site is an ``anonymous access'' system, which 
means EPA will not know your identity or contact information unless you 
provide it in the body of your comment. If you send an email comment 
directly to EPA without going through www.regulations.gov your email 
address will be automatically captured and included as part of the 
comment that is placed in the public docket and made available on the 
Internet. If you submit an electronic comment, EPA recommends that you 
include your

[[Page 40140]]

name and other contact information in the body of your comment and with 
any disk or CD-ROM you submit. If EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider your comment. Electronic files should avoid 
the use of special characters, any form of encryption, and be free of 
any defects or viruses. For additional information about EPA's public 
docket visit the EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.
    NHTSA: Your comments must be written and in English. To ensure that 
your comments are correctly filed in the Docket, please include the 
Docket number NHTSA-2014-0132 in your comments. Your comments must not 
be more than 15 pages long.\1\ NHTSA established this limit to 
encourage you to write your primary comments in a concise fashion. 
However, you may attach necessary additional documents to your 
comments, and there is no limit on the length of the attachments. If 
you are submitting comments electronically as a PDF (Adobe) file, we 
ask that the documents submitted be scanned using the Optical Character 
Recognition (OCR) process, thus allowing the agencies to search and 
copy certain portions of your submissions.\2\ Please note that pursuant 
to the Data Quality Act, in order for the substantive data to be relied 
upon and used by the agency, it must meet the information quality 
standards set forth in the OMB and Department of Transportation (DOT) 
Data Quality Act guidelines. Accordingly, we encourage you to consult 
the guidelines in preparing your comments. OMB's guidelines may be 
accessed at http://www.whitehouse.gov/omb/fedreg/reproducible.html. 
DOT's guidelines may be accessed at http://www.dot.gov/dataquality.htm.
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    \1\ See 49 CFR 553.21.
    \2\ Optical character recognition (OCR) is the process of 
converting an image of text, such as a scanned paper document or 
electronic fax file, into computer-editable text.
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(2) Tips for Preparing Your Comments

    When submitting comments, please remember to:
     Identify the rulemaking by docket number and other 
identifying information (subject heading, Federal Register date and 
page number).
     Explain why you agree or disagree, suggest alternatives, 
and substitute language for your requested changes.
     Describe any assumptions and provide any technical 
information and/or data that you used.
     If you estimate potential costs or burdens, explain how 
you arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
     Provide specific examples to illustrate your concerns, and 
suggest alternatives.
     Explain your views as clearly as possible, avoiding the 
use of profanity or personal threats.
     Make sure to submit your comments by the comment period 
deadline identified in the DATES section above.

(3) How can I be sure that my comments were received?

    NHTSA: If you submit your comments by mail and wish Docket 
Management to notify you upon its receipt of your comments, enclose a 
self-addressed, stamped postcard in the envelope containing your 
comments. Upon receiving your comments, Docket Management will return 
the postcard by mail.

(4) How do I submit confidential business information?

    Any confidential business information (CBI) submitted to one of the 
agencies will also be available to the other agency. However, as with 
all public comments, any CBI information only needs to be submitted to 
either one of the agencies' dockets and it will be available to the 
other. Following are specific instructions for submitting CBI to either 
agency. If you have any questions about CBI or the procedures for 
claiming CBI, please consult the persons identified in the FOR FURTHER 
INFORMATION CONTACT section.
    EPA: Do not submit CBI to EPA through www.regulations.gov or email. 
Clearly mark the part or all of the information that you claim to be 
CBI. For CBI information in a disk or CD ROM that you mail to EPA, mark 
the outside of the disk or CD ROM as CBI and then identify 
electronically within the disk or CD ROM the specific information that 
is claimed as CBI. Information not marked as CBI will be included in 
the public docket without prior notice. In addition to one complete 
version of the comment that includes information claimed as CBI, a copy 
of the comment that does not contain the information claimed as CBI 
must be submitted for inclusion in the public docket. Information so 
marked will not be disclosed except in accordance with procedures set 
forth in 40 CFR part 2.
    NHTSA: If you wish to submit any information under a claim of 
confidentiality, you should submit three copies of your complete 
submission, including the information you claim to be confidential 
business information, to the Chief Counsel, NHTSA, at the address given 
above under FOR FURTHER INFORMATION CONTACT. When you send a comment 
containing confidential business information, you should include a 
cover letter setting forth the information specified in our 
confidential business information regulation.\3\
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    \3\ See 49 CFR part 512.
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    In addition, you should submit a copy from which you have deleted 
the claimed confidential business information to the Docket by one of 
the methods set forth above.

(5) How can I read the comments submitted by other people?

    You may read the materials placed in the docket for this document 
(e.g., the comments submitted in response to this document by other 
interested persons) at any time by going to http://www.regulations.gov. 
Follow the online instructions for accessing the dockets. You may also 
read the materials at the EPA Docket Center or NHTSA Docket Management 
Facility by going to the street addresses given above under ADDRESSES.

(6) How do I participate in the public hearings?

    EPA and NHTSA will announce the public hearing dates and locations 
for this proposal in a supplemental Federal Register document. At all 
hearings, both agencies will accept comments on the rulemaking, and 
NHTSA will also accept comments on the EIS.
    If you would like to present testimony at the public hearings, we 
ask that you notify EPA and NHTSA contact persons listed in the FOR 
FURTHER INFORMATION CONTACT section at least ten days before the 
hearing. Once EPA and NHTSA learn how many people have registered to 
speak at the public hearing, we will allocate an appropriate amount of 
time to each participant. For planning purposes, each speaker should 
anticipate speaking for approximately ten minutes, although we may need 
to adjust the time for each speaker if there is a large turnout. We 
suggest that you bring copies of your statement or other material for 
EPA and NHTSA panels. It would also be helpful if you send us a copy of 
your statement or other materials before the hearing. To accommodate as 
many speakers as possible, we prefer that speakers not use 
technological aids (e.g., audio-visuals, computer slideshows). However, 
if you plan to do so, you must notify the contact persons in the FOR 
FURTHER INFORMATION CONTACT section above. You also must make 
arrangements to provide your presentation or any other

[[Page 40141]]

aids to EPA and NHTSA in advance of the hearing in order to facilitate 
set-up. In addition, we will reserve a block of time for anyone else in 
the audience who wants to give testimony. The agencies will assume that 
comments made at the hearings are directed to the proposed rule unless 
commenters specifically reference NHTSA's EIS in oral or written 
testimony.
    The hearing will be held at a site accessible to individuals with 
disabilities. Individuals who require accommodations such as sign 
language interpreters should contact the persons listed under FOR 
FURTHER INFORMATION CONTACT section above no later than ten days before 
the date of the hearing.
    EPA and NHTSA will conduct the hearing informally, and technical 
rules of evidence will not apply. We will arrange for a written 
transcript of the hearing and keep the official record of the hearing 
open for 30 days to allow you to submit supplementary information. You 
may make arrangements for copies of the transcript directly with the 
court reporter.

C. Did EPA conduct a peer review before issuing this notice?

    This regulatory action is supported by influential scientific 
information. Therefore, EPA conducted a peer review consistent with 
OMB's Final Information Quality Bulletin for Peer Review. As described 
in Section II.C.3, a peer review of updates to the vehicle simulation 
model (GEM) for the proposed Phase 2 standards has been completed. This 
version of GEM is based on the model used for the Phase 1 rule, which 
was peer-reviewed by a panel of four independent subject matter experts 
(from academia and a national laboratory). The peer review report and 
the agency's response to the peer review comments are available in 
Docket ID No. EPA-HQ-OAR-2014-0827.

D. Executive Summary

(1) Commitment to Greenhouse Gas Emission Reductions and Vehicle Fuel 
Efficiency

    As part of the Climate Action Plan announced in June 2013,\4\ the 
President directed the Environmental Protection Agency (EPA) and the 
Department of Transportation's (DOT) National Highway Traffic Safety 
Administration (NHTSA) to set the next round of standards to reduce 
greenhouse gas (GHG) emissions and improve fuel efficiency for medium- 
and heavy-duty vehicles. More than 70 percent of the oil used in the 
United States and 28 percent of GHG emissions come from the 
transportation sector, and since 2009 EPA and NHTSA have worked with 
industry and states to develop ambitious, flexible standards for both 
the fuel economy and GHG emissions of light-duty vehicles and the fuel 
efficiency and GHG emissions of heavy-duty vehicles.5 6 The 
standards proposed here (referred to as Phase 2) would build on the 
light-duty vehicle standards spanning model years 2011 to 2025 and on 
the initial phase of standards (referred to as Phase 1) for new medium 
and heavy-duty vehicles (MDVs and HDVs) and engines in model years 2014 
to 2018. Throughout every stage of development for these programs, EPA 
and NHTSA (collectively, the agencies, or ``we'') have worked in close 
partnership not only with one another, but with the vehicle 
manufacturing industry, environmental community leaders, and the State 
of California among other entities to create a single, effective set of 
national standards.
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    \4\ The White House, The President's Climate Action Plan (June, 
2013). http://www.whitehouse.gov/share/climate-action-plan.
    \5\ The White House, Improving the Fuel Efficiency of American 
Trucks--Bolstering Energy Security, Cutting Carbon Pollution, Saving 
Money and Supporting Manufacturing Innovation (Feb. 2014), 2.
    \6\ U.S. Environmental Protection Agency. 2014. Inventory of 
U.S. Greenhouse Gas Emissions and Sinks: 1990-2012. EPA 430-R-14-
003. Mobile sources emitted 28 percent of all U.S. GHG emissions in 
2012. Available at http://www.epa.gov/climatechange/Downloads/ghgemissions/US-GHG-Inventory-2014-Main-Text.pdf.
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    Through two previous rulemakings, EPA and NHTSA have worked with 
the auto industry to develop new fuel economy and GHG emission 
standards for light-duty vehicles. Taken together, the light-duty 
vehicle standards span model years 2011 to 2025 and are the first 
significant improvement in fuel economy in approximately two decades. 
Under the final program, average new car and light truck fuel economy 
is expected to double by 2025.\7\ This is projected to save consumers 
$1.7 trillion at the pump--roughly $8,200 per vehicle for a MY2025 
vehicle--reducing oil consumption by 2.2 million barrels a day in 2025 
and slashing GHG emissions by 6 billion metric tons over the lifetime 
of the vehicles sold during this period.\8\ These fuel economy 
standards are already delivering savings for American drivers. Between 
model years 2008 and 2013, the unadjusted average test fuel economy of 
new passenger cars and light trucks sold in the United States has 
increased by about four miles per gallon. Altogether, light-duty 
vehicle fuel economy standards finalized after 2008 have already saved 
nearly one billion gallons of fuel and avoided more than 10 million 
tons of carbon dioxide emissions.\9\
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    \7\ Id.
    \8\ Id.
    \9\ Id. at 3.
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    Similarly, EPA and NHTSA have previously developed joint GHG 
emission and fuel efficiency standards for MDVs and HDVs. Prior to 
these Phase 1 standards, heavy-duty trucks and buses--from delivery 
vans to the largest tractor-trailers--were required to meet pollution 
standards for soot and smog-causing air pollutants, but no requirements 
existed for the fuel efficiency or carbon pollution from these 
vehicles.\10\ By 2010, total fuel consumption and GHG emissions from 
MDVs and HDVs had been growing, and these vehicles accounted for 23 
percent of total U.S. transportation-related GHG emissions.\11\ In 
August 2011, the agencies finalized the groundbreaking Phase 1 
standards for new MDVs and HDVs in model years 2014 through 2018. This 
program, developed with support from the trucking and engine 
industries, the State of California, Environment Canada, and leaders 
from the environmental community, set standards that are expected to 
save a projected 530 million barrels of oil and reduce carbon emissions 
by about 270 million metric tons, representing one of the most 
significant programs available to reduce domestic emissions of 
GHGs.\12\ The Phase 1 program, as well as the many additional actions 
called for in the President's 2013 Climate Action Plan \13\ including 
this Phase 2 rulemaking, not only result in meaningful decreases in GHG 
emissions, but support--indeed are critical for--United States 
leadership to encourage other countries to also achieve meaningful GHG 
reductions.
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    \10\ Id.
    \11\ Id.
    \12\ Id. at 4.
    \13\ The President's Climate Action Plan calls for GHG-cutting 
actions including, for example, reducing carbon emissions from power 
plants and curbing hydrofluorocarbon and methane emissions.
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    This proposal builds on our commitment to robust collaboration with 
stakeholders and the public. It follows an expansive and thorough 
outreach effort in which the agencies gathered input, data and views 
from many interested stakeholders, involving over 200 meetings with 
heavy-duty vehicle and engine manufacturers, technology suppliers, 
trucking fleets, truck drivers, dealerships, environmental 
organizations, and state agencies. As with the previous light-duty 
rules and the heavy-duty Phase 1 rule, the agencies have consulted

[[Page 40142]]

frequently with the California Air Resources Board staff during the 
development of this Phase 2 proposal, given California's unique ability 
among the states to adopt their own GHG standards for on-highway 
engines and vehicles. The agencies look forward to feedback and ongoing 
conversation following the release of this proposed rule from all 
stakeholders--including through planned public hearings, written 
comments, and other opportunities for input.

(2) Overview of Phase 1 Medium- and Heavy-Duty Vehicle Standards

    The President's direction to EPA and NHTSA to develop GHG emission 
and fuel efficiency standards for MDVs and HDVs resulted in the 
agencies' promulgation of the Phase 1 program in 2011, which covers new 
trucks and heavy vehicles in model years 2014 to 2018. The Phase 1 
program includes specific standards for combination tractors, heavy-
duty pickup trucks and vans, and vocational vehicles, and includes 
separate standards for both vehicles and engines. The program offers 
extensive flexibility, allowing manufacturers to reach standards 
through average fleet calculations, a mix of technologies, and the use 
of various credit and banking programs.
    The Phase 1 program was developed through close consultation with 
industry and other stakeholders, resulting in standards tailored to the 
specifics of each different class of vehicles and engines.
     Heavy-duty combination tractors. Combination tractors--
semi trucks that typically pull trailers--are regulated under nine 
subcategories based on weight class, cab type, and roof height. These 
vehicles represent approximately two-thirds of all fuel consumption and 
GHG emissions from MDVs and HDVs.
     Heavy-duty pickup trucks and vans. Heavy-duty pickup and 
van standards are based on a ``work factor'' attribute that combines a 
vehicle's payload, towing capabilities, and the presence of 4-wheel 
drive. These vehicles represent about 15 percent of the fuel 
consumption and GHG emissions from MDVs and HDVs.
     Vocational vehicles. Specialized vocational vehicles, 
which consist of a very wide variety of truck and bus types (e.g., 
delivery, refuse, utility, dump, cement, transit bus, shuttle bus, 
school bus, emergency vehicles, and recreational vehicles) are 
regulated in three subcategories based on engine classification. These 
vehicles represent approximately 20 percent of the fuel consumption and 
GHG emissions from MDVs and HDVs. The Phase 1 program includes EPA GHG 
standards for recreational vehicles, but not NHTSA fuel efficiency 
standards.\14\
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    \14\ The proposed Phase 2 program would also include NHTSA 
recreational vehicle fuel efficiency standards.
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     Heavy-duty engines. In addition to vehicle types, the 
Phase 1 rule has separate standards for heavy-duty engines, to assure 
they contribute to the overall vehicle reductions in fuel consumption 
and GHG emissions.
    The Phase 1 standards are premised on utilization of immediately 
available technologies. The Phase 1 program provides flexibilities that 
facilitate compliance. These flexibilities help provide sufficient lead 
time for manufacturers to make necessary technological improvements and 
reduce the overall cost of the program, without compromising overall 
environmental and fuel consumption objectives. The primary flexibility 
provisions are an engine averaging, banking, and trading (ABT) program 
and a vehicle ABT program. These ABT programs allow for emission and/or 
fuel consumption credits to be averaged, banked, or traded within each 
of the regulatory subcategories. However, credits are not allowed to be 
transferred across subcategories.
    The Phase 1 program is projected to save 530 million barrels of oil 
and avoid 270 million metric tons of GHG emissions.\15\ At the same 
time, the program is projected to produce $50 billion in fuel savings, 
and net societal benefits of $49 billion. Today, the Phase 1 fuel 
efficiency and GHG reduction standards are already reducing GHG 
emissions and U.S. oil consumption, and producing fuel savings for 
America's trucking industry. The market appears to be very accepting of 
the new technology, and the agencies have seen no evidence of ``pre-
buy'' effects in response to the standards.
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    \15\ The White House, Improving the Fuel Efficiency of American 
Trucks--Bolstering Energy Security, Cutting Carbon Pollution, Saving 
Money and Supporting Manufacturing Innovation (Feb. 2014), 4.
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(3) Overview of Proposed Phase 2 Medium- and Heavy-Duty Vehicle 
Standards

    The Phase 2 GHG and fuel efficiency standards for MDVs and HDVs are 
a critical next step in improving fuel efficiency and reducing GHG. The 
proposed Phase 2 standards carry forward our commitment to meaningful 
collaboration with stakeholders and the public, as they build on more 
than 200 meetings with manufacturers, suppliers, trucking fleets, 
dealerships, state air quality agencies, non-governmental organizations 
(NGOs), and other stakeholders to identify and understand the 
opportunities and challenges involved with this next level of fuel 
saving technology. These meetings have been invaluable to the agencies, 
enabling the development of a proposal that appropriately balances all 
potential impacts and effectively minimizes the possibility of 
unintended consequences.
    Phase 2 would include technology-advancing standards that would 
phase in over the long-term (through model year 2027) to result in an 
ambitious, yet achievable program that would allow manufacturers to 
meet standards through a mix of different technologies at reasonable 
cost. The Phase 2 standards would maintain the underlying regulatory 
structure developed in the Phase 1 program, such as the general 
categorization of MDVs and HDVs and the separate standards for vehicles 
and engines. However, the Phase 2 program would build on and advance 
Phase 1 in a number of important ways including: Basing standards not 
only on currently available technologies but also on utilization of 
technologies now under development or not yet widely deployed while 
providing significant lead time to assure adequate time to develop, 
test, and phase in these controls; developing standards for trailers; 
further encouraging innovation and providing flexibility; including 
vehicles produced by small business manufacturers; incorporating 
enhanced test procedures that (among other things) allow individual 
drivetrain and powertrain performance to be reflected in the vehicle 
certification process; and using an expanded and improved compliance 
simulation model.
     Strengthening standards to account for ongoing 
technological advancements. Relative to the baseline as of the end of 
Phase 1, the proposed standards (labeled Alternative 3 or the 
``preferred alternative'' throughout this proposal) would achieve 
vehicle fuel savings of up to 8 percent and 24 percent, depending on 
the vehicle category. While costs are higher than for Phase 1, benefits 
greatly exceed costs, and payback periods are short, meaning that 
consumers will see substantial net savings over the vehicle lifetime. 
Payback is estimated at about two years for tractors and trailers, 
about five years for vocational vehicles, and about three years for 
heavy-duty pickups and vans. The agencies are further proposing to 
phase in these MY 2027 standards with interim standards for model years 
2021 and 2024 (and for certain types of trailers, EPA is proposing 
model year 2018 phase-in standards as well).

[[Page 40143]]

    In addition to the proposed standards, the agencies are considering 
another alternative (Alternative 4), which would achieve the same 
performance as the proposed standards 2-3 years earlier, leading to 
overall reductions in fuel use and greenhouse gas emissions. The 
agencies believe Alternative 4 has the potential to be the maximum 
feasible and appropriate alternative; however, based on the evidence 
currently before us, EPA and NHTSA have outstanding questions regarding 
relative risks and benefits of Alternative 4 due to the timeframe 
envisioned by that alternative. The agencies are proposing Alternative 
3 based on their analyses and projections, and taking into account the 
agencies' respective statutory considerations. The comments that the 
agencies receive on this proposal will be instrumental in helping us 
determine standards that are appropriate (for EPA) and maximum feasible 
(for NHTSA), given the discretion that both agencies have under our 
respective statutes. Therefore, the agencies have presented different 
options and raised specific questions throughout the proposed rule, 
focusing in particular on better understanding the perspectives on the 
feasible adoption rates of different technologies, considering 
associated costs and necessary lead time.
     Setting standards for trailers for the first time. In 
addition to retaining the vehicle and engine categories covered in the 
Phase 1 program, which include semi tractors, heavy-duty pickup trucks 
and work vans, vocational vehicles, and separate standards for heavy-
duty engines, the Phase 2 standards propose fuel efficiency and GHG 
emission standards for trailers used in combination with tractors. 
Although the agencies are not proposing standards for all trailer 
types, the majority of new trailers would be covered.
     Encouraging technological innovation while providing 
flexibility and options for manufacturers. For each category of HDVs, 
the standards would set performance targets that allow manufacturers to 
achieve reductions through a mix of different technologies and leave 
manufacturers free to choose any means of compliance. For tractors and 
vocational vehicles, enhanced test procedures and an expanded and 
improved compliance simulation model enable the proposed vehicle 
standards to encompass more of the complete vehicle and to account for 
engine, transmission and driveline improvements than the Phase 1 
program. With the addition of the powertrain and driveline to the 
compliance model, representative drive cycles and vehicle baseline 
configurations become critically important to assure the standards 
promote technologies that improve real world fuel efficiency and GHG 
emissions. This proposal updates drive cycles and vehicle 
configurations to better reflect real world operation. For tractor 
standards, for example, different combinations of improvements like 
advanced aerodynamics, engine improvements and waste-heat recovery, 
automated transmission, and lower rolling resistance tires and 
automatic tire inflation can be used to meet standards. Additionally, 
the agencies' analyses indicate that this proposal should have no 
adverse impact on vehicle or engine safety.
     Providing flexibilities to help minimize effect on small 
businesses. All small businesses are exempt from the Phase 1 standards. 
The agencies are proposing to regulate small business entities under 
Phase 2 (notably certain trailer manufacturers), but have conducted 
extensive proceedings pursuant to Section 609 of the Regulatory 
Flexibility Act, and otherwise have engaged in extensive consultation 
with stakeholders, and developed a proposed approach to provide 
targeted flexibilities geared toward helping small businesses comply 
with the Phase 2 standards. Specifically, the agencies are proposing to 
delay all new requirements by one year and simplify certification 
requirements for small businesses, and are further proposing additional 
specific flexibilities adapted to particular types of trailers.

   Summary of the Proposed Phase 2 Medium- and Heavy-Duty Vehicle Rule
 Impacts to Fuel Consumption, GHG Emissions, Benefits and Costs Over the
  Lifetime of Model Years 2018-2029, Based on Analysis Method A \a\ \b\
                                   \c\
------------------------------------------------------------------------
                                                3%              7%
------------------------------------------------------------------------
Fuel Reductions (billion gallons).......               72-77
GHG Reductions (MMT, CO2eq).............             974-1034
------------------------------------------------------------------------
Pre-Tax Fuel Savings ($billion).........         165-175           89-94
Discounted Technology Costs ($billion)..         25-25.4      16.8 -17.1
Value of reduced emissions ($billion)...       70.1-73.7       52.9-55.6
Total Costs ($billion)..................       30.5-31.1       20.0-20.5
Total Benefits ($billion)...............         261-276         156-165
Net Benefits ($billion).................         231-245         136-144
------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section
  I.D; for an explanation of the less dynamic baseline, 1a, and more
  dynamic baseline, 1b, please see Section X.A.1.
\b\ Range reflects two reference case assumptions, one that projects
  very little improvement in new vehicle fuel efficiency absent new
  standards, and the second that projects more significant improvements
  in vehicle fuel efficiency absent new standards.
\c\ Benefits and net benefits (including those in the 7% discount rate
  column) use the 3 percent average SCC-CO2 value applied only to CO2
  emissions; GHG reductions include CO2, CH4, N2O and HFC reductions.


  Summary of the Proposed Phase 2 Medium- and Heavy-Duty Vehicle Annual
  Fuel and GHG Reductions, Program Costs, Benefits and Net Benefits in
      Calendar Years 2035 and 2050, Based on Analysis Method B \a\
------------------------------------------------------------------------
                                               2035            2050
------------------------------------------------------------------------
Fuel Reductions (Billion Gallons).......             9.3            13.4
GHG Reduction (MMT, CO2eq)..............           127.1           183.4
Vehicle Program Costs (including                   -$6.0           -$7.1
 Maintenance; Billions of 2012$)........
Fuel Savings (Pre-Tax; Billions of                 $37.2           $57.5
 2012$).................................
Benefits (Billions of 2012$)............           $20.5           $32.9

[[Page 40144]]

 
Net Benefits (Billions of 2012$)........           $51.7           $83.2
------------------------------------------------------------------------
Note:
\a\ Benefits and net benefits use the 3 percent average SCC-CO2 value
  applied only to CO2 emissions; GHG reductions include CO2, CH4, N2O
  and HFC reductions; values reflect the preferred alternative relative
  to the less dynamic baseline (a reference case that projects very
  little improvement in new vehicle fuel economy absent new standards.


  Summary of the Proposed Phase 2 Medium- and Heavy-Duty Vehicle Program Expected Per-Vehicle Fuel Savings, GHG
            Emission Reductions, and Cost for Key Vehicle Categories, Based on Analysis Method B \a\
----------------------------------------------------------------------------------------------------------------
                                            MY 2021                    MY 2024                   MY 2027
----------------------------------------------------------------------------------------------------------------
Maximum Vehicle Fuel Savings and
 Tailpipe GHG Reduction (%)
    Tractors.....................  13                         20                        24
    Trailers \b\.................  4                          6                         8
    Vocational Vehicles..........  7                          11                        16
    Pickups/Vans.................  2.5                        10                        16
Per Vehicle Cost ($) \c\ (%
 Increase in Typical Vehicle
 Price) \d\
    Tractors.....................  $6,710 (7%)                $9,940 (10%)              $11,680 (12%)
    Trailers.....................  $900 (4%)                  $1,010 (4%)               $1,170 (5%)
    Vocational Vehicles..........  $1,150 (2%)                $1,770 (3%)               $3,380 (5%)
    Pickups/Vans.................  $520 (1%)                  $950 (2%)                 $1,340 (3%)
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ Note that the proposed EPA standards for some categories of box trailers begin in model year 2018; values
  reflect the preferred alternative relative to the less dynamic baseline (a reference case that projects very
  little improvement in new vehicle fuel economy absent new standards.
\b\ All engine costs are included.
\c\ For this table, we use a minimum vehicle price today of $100,000 for tractors, $25,000 for trailers, $70,000
  for vocational vehicles and $40,000 for HD pickups/vans.



 Payback Periods for MY2027 Vehicles Under the Proposed Standards, Based
                          on Analysis Method B
        [Payback occurs in the year shown; using 7% discounting]
------------------------------------------------------------------------
                                                             Proposed
                                                             standards
------------------------------------------------------------------------
Tractors/Trailers.......................................             2nd
Vocational Vehicles.....................................             6th
Pickups/Vans............................................             3rd
------------------------------------------------------------------------

(4) Issues Addressed in This Proposed Rule

    This proposed rule contains extensive discussion of the background, 
elements, and implications of the proposed Phase 2 program. Section I 
includes information on the MDV and HDV industry, related regulatory 
and non-regulatory programs, summaries of Phase 1 and Phase 2 programs, 
costs and benefits of the proposed standards, and relevant statutory 
authority for EPA and NHTSA. Section II discusses vehicle simulation, 
engine standards, and test procedures. Sections III, IV, V, and VI 
detail the proposed standards for combination tractors, trailers, 
vocational vehicles, and heavy-duty pickup trucks and vans. Sections 
VII and VIII discuss aggregate GHG impacts, fuel consumption impacts, 
climate impacts, and impacts on non-GHG emissions. Section IX evaluates 
the economic impacts of the proposed standards. Sections X, XI, and XII 
present the alternatives analyses, consideration of natural gas 
vehicles, and the agencies' initial response to recommendations from 
the Academy of Sciences. Finally, Sections XIII and XIV discuss the 
changes that the proposed Phase 2 rules would have on Phase 1 standards 
and other regulatory provisions. In addition to this preamble, the 
agencies have also prepared a joint Draft Regulatory Impact Analysis 
(DRIA) which is available on our respective Web sites and in the public 
docket for this rulemaking which provides additional data, analysis and 
discussion of the proposed standards and the alternatives analyzed by 
the agencies. We request comment on all aspects of this proposed 
rulemaking, including the DRIA.

Table of Contents

    A. Does this action apply to me?
    B. Public Participation
    C. Did EPA conduct a peer review before issuing this notice?
    D. Executive Summary
I. Overview
    A. Background
    B. Summary of Phase 1 Program
    C. Summary of the Proposed Phase 2 Standards and Requirements
    D. Summary of the Costs and Benefits of the Proposed Rule
    E. EPA and NHTSA Statutory Authorities
    F. Other Issues
II. Vehicle Simulation, Engine Standards and Test Procedures
    A. Introduction and Summary of Phase 1 and Phase 2 Regulatory 
Structures
    B. Phase 2 Proposed Regulatory Structure
    C. Proposed Vehicle Simulation Model--Phase 2 GEM
    D. Proposed Engine Test Procedures and Engine Standards
III. Class 7 and 8 Combination Tractors
    A. Summary of the Phase 1 Tractor Program
    B. Overview of the Proposed Phase 2 Tractor Program
    C. Proposed Phase 2 Tractor Standards
    D. Feasibility of the Proposed Tractor Standards
    E. Proposed Compliance Provisions for Tractors
    F. Flexibility Provisions
IV. Trailers
    A. Summary of Trailer Consideration in Phase 1
    B. The Trailer Industry
    C. Proposed Phase 2 Trailer Standards
    D. Feasibility of the Proposed Trailer Standards
    E. Alternative Standards and Feasibility Considered
    F. Trailer Standards: Compliance and Flexibilities
V. Class 2b-8 Vocational Vehicles
    A. Summary of Phase 1 Vocational Vehicle Standards

[[Page 40145]]

    B. Proposed Phase 2 Standards for Vocational Vehicles
    C. Feasibility of the Proposed Vocational Vehicle Standards
    D. Alternative Vocational Vehicle Standards Considered
    E. Compliance Provisions for Vocational Vehicles
VI. Heavy-Duty Pickups and Vans
    A. Introduction and Summary of Phase 1 HD Pickup and Van 
Standards
    B. Proposed HD Pickup and Van Standards
    C. Feasibility of Pickup and Van Standards
    D. DOT CAFE Model Analysis of the Regulatory Alternatives for HD 
Pickups and Vans
    E. Compliance and Flexibility for HD Pickup and Van Standards
VII. Aggregate GHG, Fuel Consumption, and Climate Impacts
    A. What methodologies did the agencies use to project GHG 
emissions and fuel consumption impacts?
    B. Analysis of Fuel Consumption and GHG Emissions Impacts 
Resulting From Proposed Standards and Alternative 4
    C. What are the projected reductions in fuel consumption and GHG 
emissions?
VIII. How will this proposed action impact non-GHG emissions and 
their associated effects?
    A. Emissions Inventory Impacts
    B. Health Effects of Non-GHG Pollutants
    C. Environmental Effects of Non-GHG Pollutants
    D. Air Quality Impacts of Non-GHG Pollutants
IX. Economic and Other Impacts
    A. Conceptual Framework
    B. Vehicle-Related Costs Associated With the Program
    C. Changes in Fuel Consumption and Expenditures
    D. Maintenance Expenditures
    E. Analysis of the Rebound Effect
    F. Impact on Class Shifting, Fleet Turnover, and Sales
    G. Monetized GHG Impacts
    H. Monetized Non-GHG Health Impacts
    I. Energy Security Impacts
    J. Other Impacts
    K. Summary of Benefits and Costs
    L. Employment Impacts
    M. Cost of Ownership and Payback Analysis
    N. Safety Impacts
X. Analysis of the Alternatives
    A. What are the alternatives that the agencies considered?
    B. How do these alternatives compare in overall fuel consumption 
and GHG emissions reductions and in benefits and costs?
XI. Natural Gas Vehicles and Engines
    A. Natural Gas Engine and Vehicle Technology
    B. GHG Lifecycle Analysis for Natural Gas Vehicles
    C. Projected Use of LNG and CNG
    D. Natural Gas Emission Control Measures
    E. Dimethyl Ether
XII. Agencies' Response to Recommendations From the National Academy 
of Sciences
    A. Overview
    B. Major Findings and Recommendations of the NAS Phase 2 First 
Report
XIII. Amendments to Phase 1 Standards
    A. EPA Amendments
    B. Other Compliance Provisions for NHTSA
XIV. Other Proposed Regulatory Provisions
    A. Proposed Amendments Related to Heavy-Duty Highway Engines and 
Vehicles
    B. Amendments Affecting Gliders and Glider Kits
    C. Applying the General Compliance Provisions of 40 CFR Part 
1068 to Light-Duty Vehicles, Light-Duty Trucks, Chassis-Certified 
Class 2B and 3 Heavy-Duty Vehicles and Highway Motorcycles
    D. Amendments to General Compliance Provisions in 40 CFR Part 
1068
    E. Amendments to Light-Duty Greenhouse Gas Program Requirements
    F. Amendments to Highway and Nonroad Test Procedures and 
Certification Requirements
    G. Amendments Related to Nonroad Diesel Engines in 40 CFR Part 
1039
    H. Amendments Related to Marine Diesel Engines in 40 CFR Parts 
1042 and 1043
    I. Amendments Related to Locomotives in 40 CFR Part 1033
    J. Miscellaneous EPA Amendments
    K. Amending 49 CFR Parts 512 and 537 To Allow Electronic 
Submissions and Defining Data Formats for Light-Duty Vehicle 
Corporate Average Fuel Economy (CAFE) Reports
XV. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. National Environmental Policy Act
    C. Paperwork Reduction Act
    D. Regulatory Flexibility Act
    E. Unfunded Mandates Reform Act
    F. Executive Order 13132: Federalism
    G. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    H. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    I. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    J. National Technology Transfer and Advancement Act and 1 CFR 
Part 51
    K. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations
    L. Endangered Species Act
XVI. EPA and NHTSA Statutory Authorities
    A. EPA
    B. NHTSA
    C. List of Subjects

I. Overview

A. Background

    This background and summary of the proposed Phase 2 GHG emissions 
and fuel efficiency standards includes an overview of the heavy-duty 
truck industry and related regulatory and non-regulatory programs, a 
summary of the Phase 1 GHG emissions and fuel efficiency program, a 
summary of the proposed Phase 2 standards and requirements, a summary 
of the costs and benefits of the proposed Phase 2 standards, discussion 
of EPA and NHTSA statutory authorities, and other issues.
    For purposes of this preamble, the terms ``heavy-duty'' or ``HD'' 
are used to apply to all highway vehicles and engines that are not 
within the range of light-duty passenger cars, light-duty trucks, and 
medium-duty passenger vehicles (MDPV) covered by separate GHG and 
Corporate Average Fuel Economy (CAFE) standards.\16\ They do not 
include motorcycles. Thus, in this rulemaking, unless specified 
otherwise, the heavy-duty category incorporates all vehicles with a 
gross vehicle weight rating above 8,500 lbs, and the engines that power 
them, except for MDPVs.17 18
---------------------------------------------------------------------------

    \16\ 2017 and Later Model Year Light-Duty Vehicle Greenhouse Gas 
Emissions and Corporate Average Fuel Economy Standards; Final Rule, 
77 FR 62623, October 15, 2012.
    \17\ The CAA defines heavy-duty as a truck, bus or other motor 
vehicles with a gross vehicle weight rating exceeding 6,000 lbs (CAA 
section 202(b)(3)). The term HD as used in this action refers to a 
subset of these vehicles and engines.
    \18\ The Energy Independence and Security Act of 2007 requires 
NHTSA to set standards for commercial medium- and heavy-duty on-
highway vehicles, defined as on-highway vehicles with a GVWR of 
10,000 lbs or more, and work trucks, defined as vehicles with a GVWR 
between 8,500 and 10,000 lbs and excluding medium duty passenger 
vehicles.
---------------------------------------------------------------------------

    Consistent with the President's direction, over the past two years 
as we have developed this proposal, the agencies have met on an on-
going basis with a very large number of diverse stakeholders. This 
includes meetings, and in many cases site visits, with truck, trailer, 
and engine manufacturers; technology supplier companies and their trade 
associations (e.g., transmissions, drive lines, fuel systems, 
turbochargers, tires, catalysts, and many others); line haul and 
vocational trucking firms and trucking associations; the trucking 
industries owner-operator association; truck dealerships and dealers 
associations; trailer manufacturers and their trade association; non-
governmental organizations (NGOs, including environmental NGOs, 
national security NGOs, and consumer advocacy NGOs); state air quality 
agencies; manufacturing labor unions; and many other stakeholders. In 
particular, NHTSA and EPA have consulted on an on-going basis with the 
California Air Resources Board (CARB) over the past two years as we 
have developed the Phase 2 proposal. In addition, CARB staff and 
managers have also participated with EPA and NHTSA in meetings with

[[Page 40146]]

many external stakeholders, in particular with vehicle OEMs and 
technology suppliers.\19\
---------------------------------------------------------------------------

    \19\ Vehicle chassis manufacturers are known in this industry as 
original equipment manufacturers or OEMs.
---------------------------------------------------------------------------

    NHTSA and EPA staff also participated in a large number of 
technical and policy conferences over the past two years related to the 
technological, economic, and environmental aspects of the heavy-duty 
trucking industry. The agencies also met with regulatory counterparts 
from several other nations who either have already or are considering 
establishing fuel consumption or GHG requirements, including outreach 
with representatives from the governments of Canada, the European 
Commission, Japan, and China.
    These comprehensive outreach actions by the agencies provided us 
with information to assist in our identification of potential 
technologies that can be used to reduce heavy-duty GHG emissions and 
improve fuel efficiency. The outreach has also helped the agencies to 
identify and understand the opportunities and challenges involved with 
the proposed standards for the heavy-duty trucks, trailers, and engines 
detailed in this preamble, including time needed for implementation of 
various technologies and potential costs and fuel savings. The scope of 
this outreach effort to gather input for the proposal included well 
over 200 meetings with stakeholders. These meetings and conferences 
have been invaluable to the agencies. We believe they have enabled us 
to develop this proposal in such a way as to appropriately balance all 
of the potential impacts, to minimize the possibility of unintended 
consequences, and to ensure that we are requesting comment on a wide 
range of issues that can inform the final rule.
(1) Brief Overview of the Heavy-Duty Truck Industry
    The heavy-duty sector is diverse in several respects, including the 
types of manufacturing companies involved, the range of sizes of trucks 
and engines they produce, the types of work for which the trucks are 
designed, and the regulatory history of different subcategories of 
vehicles and engines. The current heavy-duty fleet encompasses vehicles 
from the ``18-wheeler'' combination tractors one sees on the highway to 
the largest pickup trucks and vans, as well as vocational vehicles 
covering a range between these extremes. Together, the HD sector spans 
a wide range of vehicles with often specialized form and function. A 
primary indicator of the diversity among heavy-duty trucks is the range 
of load-carrying capability across the industry. The heavy-duty truck 
sector is often subdivided by vehicle weight classifications, as 
defined by the vehicle's gross vehicle weight rating (GVWR), which is a 
measure of the combined curb (empty) weight and cargo carrying capacity 
of the truck.\20\ Table I-1 below outlines the vehicle weight 
classifications commonly used for many years for a variety of purposes 
by businesses and by several Federal agencies, including the Department 
of Transportation, the Environmental Protection Agency, the Department 
of Commerce, and the Internal Revenue Service.
---------------------------------------------------------------------------

    \20\ GVWR describes the maximum load that can be carried by a 
vehicle, including the weight of the vehicle itself. Heavy-duty 
vehicles (including those designed for primary purposes other than 
towing) also have a gross combined weight rating (GCWR), which 
describes the maximum load that the vehicle can haul, including the 
weight of a loaded trailer and the vehicle itself.

                                                        Table I-1--Vehicle Weight Classification
--------------------------------------------------------------------------------------------------------------------------------------------------------
                  Class                         2b               3               4               5               6               7               8
--------------------------------------------------------------------------------------------------------------------------------------------------------
GVWR (lb)...............................    8,501-10,000   10,001-14,000   14,001-16,000   16,001-19,500   19,501-26,000   26,001-33,000         >33,000
--------------------------------------------------------------------------------------------------------------------------------------------------------

In the framework of these vehicle weight classifications, the heavy-
duty truck sector refers to ``Class 2b'' through ``Class 8'' vehicles 
and the engines that power those vehicles.\21\
---------------------------------------------------------------------------

    \21\ Class 2b vehicles manufactured as passenger vehicles 
(Medium Duty Passenger Vehicles, MDPVs) are covered by the light-
duty GHG and fuel economy standards and therefore are not addressed 
in this rulemaking.
---------------------------------------------------------------------------

    Unlike light-duty vehicles, which are primarily used for 
transporting passengers for personal travel, heavy-duty vehicles fill 
much more diverse operator needs. Heavy-duty pickup trucks and vans 
(Classes 2b and 3) are used chiefly as work trucks and vans, and as 
shuttle vans, as well as for personal transportation, with an average 
annual mileage in the range of 15,000 miles. The rest of the heavy-duty 
sector is used for carrying cargo and/or performing specialized tasks. 
``Vocational'' vehicles, which may span Classes 2b through 8, vary 
widely in size, including smaller and larger van trucks, utility 
``bucket'' trucks, tank trucks, refuse trucks, urban and over-the-road 
buses, fire trucks, flat-bed trucks, and dump trucks, among others. The 
annual mileage of these vehicles is as varied as their uses, but for 
the most part tends to fall in between heavy-duty pickups/vans and the 
large combination tractors, typically from 15,000 to 150,000 miles per 
year.
    Class 7 and 8 combination tractor-trailers--some equipped with 
sleeper cabs and some not--are primarily used for freight 
transportation. They are sold as tractors and operate with one or more 
trailers that can carry up to 50,000 lbs or more of payload, consuming 
significant quantities of fuel and producing significant amounts of GHG 
emissions. Together, Class 7 and 8 tractors and trailers account for 
approximately two-thirds of the heavy-duty sector's total 
CO2 emissions and fuel consumption. Trailer designs vary 
significantly, reflecting the wide variety of cargo types. However, the 
most common types of trailers are box vans (dry and refrigerated), 
which are a focus of this Phase 2 rulemaking. The tractor-trailers used 
in combination applications can and frequently do travel more than 
150,000 miles per year and can operate for 20-30 years.
    EPA and NHTSA have designed our respective proposed standards in 
careful consideration of the diversity and complexity of the heavy-duty 
truck industry, as discussed in Section I.B.
(2) Related Regulatory and Non-Regulatory Programs
(a) History of EPA's Heavy-Duty Regulatory Program and Impacts of 
Greenhouse Gases on Climate Change
    This subsection provides an overview of the history of EPA's heavy-
duty regulatory program and impacts of greenhouse gases on climate 
change.
(i) History of EPA's Heavy-Duty Regulatory Program
    Since the 1980s, EPA has acted several times to address tailpipe 
emissions of criteria pollutants and air toxics from heavy-duty 
vehicles and engines. During the last two decades these programs have 
primarily

[[Page 40147]]

addressed emissions of particulate matter (PM) and the primary ozone 
precursors, hydrocarbons (HC) and oxides of nitrogen (NOX). 
These programs, which have successfully achieved significant and cost-
effective reductions in emissions and associated health and welfare 
benefits to the nation, were an important basis of the Phase 1 program. 
See e.g. 66 FR 5002, 5008, and 5011-5012 (January 18, 2001) (detailing 
substantial public health benefits of controls of criteria pollutants 
from heavy-duty diesel engines, including bringing areas into 
attainment with primary (public health) PM NAAQS, or contributing 
substantially to such attainment); National Petrochemical Refiners 
Association v. EPA, 287 F.3d 1130, 1134 (D.C. Cir. 2002) (referring to 
the ``dramatic reductions'' in criteria pollutant emissions resulting 
from those on-highway heavy-duty engine standards, and upholding all of 
the standards).
    As required by the Clean Air Act (CAA), the emission standards 
implemented by these programs include standards that apply at the time 
that the vehicle or engine is sold and continue to apply in actual use. 
EPA's overall program goal has always been to achieve emissions 
reductions from the complete vehicles that operate on our roads. The 
agency has often accomplished this goal for many heavy-duty truck 
categories by regulating heavy-duty engine emissions. A key part of 
this success has been the development over many years of a well-
established, representative, and robust set of engine test procedures 
that industry and EPA now use routinely to measure emissions and 
determine compliance with emission standards. These test procedures in 
turn serve the overall compliance program that EPA implements to help 
ensure that emissions reductions are being achieved. By isolating the 
engine from the many variables involved when the engine is installed 
and operated in a HD vehicle, EPA has been able to accurately address 
the contribution of the engine alone to overall emissions.
(ii) Impacts of Greenhouse Gases on Climate Change
    In 2009, the EPA Administrator issued the document known as the 
Endangerment Finding under CAA Section 202(a)(1).\22\ In the 
Endangerment Finding, which focused on public health and public welfare 
impacts within the United States, the Administrator found that elevated 
concentrations of GHG emissions in the atmosphere may reasonably be 
anticipated to endanger public health and welfare of current and future 
generations. See also Coalition for Responsible Regulation v. EPA, 684 
F.3d 102, 117-123 (D.C. Cir. 2012) (upholding the endangerment finding 
in all respects). The following sections summarize the key information 
included in the Endangerment Finding.
---------------------------------------------------------------------------

    \22\ ``Endangerment and Cause or Contribute Findings for 
Greenhouse Gases Under Section 202(a) of the Clean Air Act,'' 74 FR 
66496 (December 15, 2009) (``Endangerment Finding'').
---------------------------------------------------------------------------

    Climate change caused by human emissions of GHGs threatens public 
health in multiple ways. By raising average temperatures, climate 
change increases the likelihood of heat waves, which are associated 
with increased deaths and illnesses. While climate change also 
increases the likelihood of reductions in cold-related mortality, 
evidence indicates that the increases in heat mortality will be larger 
than the decreases in cold mortality in the United States. Compared to 
a future without climate change, climate change is expected to increase 
ozone pollution over broad areas of the U.S., including in the largest 
metropolitan areas with the worst ozone problems, and thereby increase 
the risk of morbidity and mortality. Other public health threats also 
stem from projected increases in intensity or frequency of extreme 
weather associated with climate change, such as increased hurricane 
intensity, increased frequency of intense storms and heavy 
precipitation. Increased coastal storms and storm surges due to rising 
sea levels are expected to cause increased drownings and other adverse 
health impacts. Children, the elderly, and the poor are among the most 
vulnerable to these climate-related health effects. See also 79 FR 
75242 (December 17, 2014) (climate change, and temperature increases in 
particular, likely to increase O3 (Ozone) pollution ``over broad areas 
of the U.S., including the largest metropolitan areas with the worst O3 
problems, increas[ing] the risk of morbidity and mortality'').
    Climate change caused by human emissions of GHGs also threatens 
public welfare in multiple ways. Climate changes are expected to place 
large areas of the country at serious risk of reduced water supplies, 
increased water pollution, and increased occurrence of extreme events 
such as floods and droughts. Coastal areas are expected to face 
increased risks from storm and flooding damage to property, as well as 
adverse impacts from rising sea level, such as land loss due to 
inundation, erosion, wetland submergence and habitat loss. Climate 
change is expected to result in an increase in peak electricity demand, 
and extreme weather from climate change threatens energy, 
transportation, and water resource infrastructure. Climate change may 
exacerbate ongoing environmental pressures in certain settlements, 
particularly in Alaskan indigenous communities. Climate change also is 
very likely to fundamentally rearrange U.S. ecosystems over the 21st 
century. Though some benefits may balance adverse effects on 
agriculture and forestry in the next few decades, the body of evidence 
points towards increasing risks of net adverse impacts on U.S. food 
production, agriculture and forest productivity as temperature 
continues to rise. These impacts are global and may exacerbate problems 
outside the U.S. that raise humanitarian, trade, and national security 
issues for the U.S. See also 79 FR 75382 (December 17, 2014) (welfare 
effects of O3 increases due to climate change, with emphasis on 
increased wildfires).
    As outlined in Section VIII.A. of the 2009 Endangerment Finding, 
EPA's approach to providing the technical and scientific information to 
inform the Administrator's judgment regarding the question of whether 
GHGs endanger public health and welfare was to rely primarily upon the 
recent, major assessments by the U.S. Global Change Research Program 
(USGCRP), the Intergovernmental Panel on Climate Change (IPCC), and the 
National Research Council (NRC) of the National Academies. These 
assessments addressed the scientific issues that EPA was required to 
examine, were comprehensive in their coverage of the GHG and climate 
change issues, and underwent rigorous and exacting peer review by the 
expert community, as well as rigorous levels of U.S. government review. 
Since the administrative record concerning the Endangerment Finding 
closed following EPA's 2010 Reconsideration Denial, a number of such 
assessments have been released. These assessments include the IPCC's 
2012 ``Special Report on Managing the Risks of Extreme Events and 
Disasters to Advance Climate Change Adaptation'' (SREX) and the 2013-
2014 Fifth Assessment Report (AR5), the USGCRP's 2014 ``Climate Change 
Impacts in the United States'' (Climate Change Impacts), and the NRC's 
2010 ``Ocean Acidification: A National Strategy to Meet the Challenges 
of a Changing Ocean'' (Ocean Acidification), 2011 ``Report on Climate 
Stabilization Targets: Emissions, Concentrations, and Impacts over 
Decades to Millennia'' (Climate Stabilization Targets), 2011 ``National 
Security Implications for U.S. Naval

[[Page 40148]]

Forces'' (National Security Implications), 2011 ``Understanding Earth's 
Deep Past: Lessons for Our Climate Future'' (Understanding Earth's Deep 
Past), 2012 ``Sea Level Rise for the Coasts of California, Oregon, and 
Washington: Past, Present, and Future'', 2012 ``Climate and Social 
Stress: Implications for Security Analysis'' (Climate and Social 
Stress), and 2013 ``Abrupt Impacts of Climate Change'' (Abrupt Impacts) 
assessments.
    EPA has reviewed these new assessments and finds that the improved 
understanding of the climate system they present strengthens the case 
that GHG emissions endanger public health and welfare.
    In addition, these assessments highlight the urgency of the 
situation as the concentration of CO2 in the atmosphere 
continues to rise. Absent a reduction in emissions, a recent National 
Research Council of the National Academies assessment projected that 
concentrations by the end of the century would increase to levels that 
the Earth has not experienced for millions of years.\23\ In fact, that 
assessment stated that ``the magnitude and rate of the present 
greenhouse gas increase place the climate system in what could be one 
of the most severe increases in radiative forcing of the global climate 
system in Earth history.'' \24\ What this means, as stated in another 
NRC assessment, is that:
---------------------------------------------------------------------------

    \23\ National Research Council, Understanding Earth's Deep Past, 
p. 1
    \24\ Id., p.138.

    Emissions of carbon dioxide from the burning of fossil fuels 
have ushered in a new epoch where human activities will largely 
determine the evolution of Earth's climate. Because carbon dioxide 
in the atmosphere is long lived, it can effectively lock Earth and 
future generations into a range of impacts, some of which could 
become very severe. Therefore, emission reductions choices made 
today matter in determining impacts experienced not just over the 
next few decades, but in the coming centuries and millennia.\25\
---------------------------------------------------------------------------

    \25\ National Research Council, Climate Stabilization Targets, 
p. 3.

    Moreover, due to the time-lags inherent in the Earth's climate, the 
Climate Stabilization Targets assessment notes that the full warming 
from any given concentration of CO2 reached will not be 
realized for several centuries.
    The recently released USGCRP ``National Climate Assessment'' \26\ 
emphasizes that climate change is already happening now and it is 
happening in the United States. The assessment documents the increases 
in some extreme weather and climate events in recent decades, the 
damage and disruption to infrastructure and agriculture, and projects 
continued increases in impacts across a wide range of peoples, sectors, 
and ecosystems.
---------------------------------------------------------------------------

    \26\ U.S. Global Change Research Program, Climate Change Impacts 
in the United States: The Third National Climate Assessment, May 
2014 Available at http://nca2014.globalchange.gov/.
---------------------------------------------------------------------------

    These assessments underscore the urgency of reducing emissions now: 
Today's emissions will otherwise lead to raised atmospheric 
concentrations for thousands of years, and raised Earth system 
temperatures for even longer. Emission reductions today will benefit 
the public health and public welfare of current and future generations.
    Finally, it should be noted that the concentration of carbon 
dioxide in the atmosphere continues to rise dramatically. In 2009, the 
year of the Endangerment Finding, the average concentration of carbon 
dioxide as measured on top of Mauna Loa was 387 parts per million.\27\ 
The average concentration in 2013 was 396 parts per million. And the 
monthly concentration in April of 2014 was 401 parts per million, the 
first time a monthly average has exceeded 400 parts per million since 
record keeping began at Mauna Loa in 1958, and for at least the past 
800,000 years according to ice core records.\28\
---------------------------------------------------------------------------

    \27\ ftp://aftp.cmdl.noaa.gov/products/trends/co2/co2_annmean_mlo.txt.
    \28\ http://www.esrl.noaa.gov/gmd/ccgg/trends/.
---------------------------------------------------------------------------

(b) The NHTSA and EPA Light-Duty National GHG and Fuel Economy Program
    On May 7, 2010, EPA and NHTSA finalized the first-ever National 
Program for light-duty cars and trucks, which set GHG emissions and 
fuel economy standards for model years 2012-2016 (see 75 FR 25324). 
More recently, the agencies adopted even stricter standards for model 
years 2017 and later (77 FR 62624, October 15, 2012). The agencies have 
used the light-duty National Program as a model for the HD National 
Program in several respects. This is most apparent in the case of 
heavy-duty pickups and vans, which are similar to the light-duty trucks 
addressed in the light-duty National Program both technologically as 
well as in terms of how they are manufactured (i.e., the same company 
often makes both the vehicle and the engine, and several light-duty 
manufacturers also manufacture HD pickups and vans).\29\ For HD pickups 
and vans, there are close parallels to the light-duty program in how 
the agencies have developed our respective heavy-duty standards and 
compliance structures. However, HD pickups and vans are true work 
vehicles that are designed for much higher towing and payload 
capabilities than are light-duty pickups and vans. The technologies 
applied to light-duty trucks are not all applicable to heavy-duty 
pickups and vans at the same adoption rates, and the technologies often 
produce a lower percent reduction in CO2 emissions and fuel 
consumption when used in heavy-duty vehicles. Another difference 
between the light-duty and the heavy-duty standards is that each agency 
adopts heavy-duty standards based on attributes other than vehicle 
footprint, as discussed below.
---------------------------------------------------------------------------

    \29\ This is more broadly true for heavy-duty pickup trucks than 
vans because every manufacturer of heavy-duty pickup trucks also 
makes light-duty pickup trucks, while only some heavy-duty van 
manufacturers also make light-duty vans.
---------------------------------------------------------------------------

    Due to the diversity of the remaining HD vehicles, there are fewer 
parallels with the structure of the light-duty program. However, the 
agencies have maintained the same collaboration and coordination that 
characterized the development of the light-duty program throughout the 
Phase 1 rulemaking and the continued efforts for Phase 2. Most notably, 
as with the light-duty program, manufacturers would continue to be able 
to design and build vehicles to meet a closely coordinated, harmonized 
national program, and to avoid unnecessarily duplicative testing and 
compliance burdens. In addition, the averaging, banking, and trading 
provisions in the HD program, although structurally different from 
those of the light-duty program, serve the same purpose, which is to 
allow manufacturers to achieve large reductions in fuel consumption and 
emissions while providing a broad mix of products to their customers. 
The agencies have also worked closely with CARB to provide harmonized 
national standards.
(c) EPA's SmartWay Program
    EPA's voluntary SmartWay Transport Partnership program encourages 
businesses to take actions that reduce fuel consumption and 
CO2 emissions while cutting costs by working with the 
shipping, logistics, and carrier communities to identify low carbon 
strategies and technologies across their transportation supply chains. 
SmartWay provides technical information, benchmarking and tracking 
tools, market incentives, and partner recognition to facilitate and 
accelerate the adoption of these strategies. Through the SmartWay 
program and its related technology assessment center, EPA has worked 
closely with truck and trailer manufacturers and truck fleets over the 
last ten years to develop test

[[Page 40149]]

procedures to evaluate vehicle and component performance in reducing 
fuel consumption and has conducted testing and has established test 
programs to verify technologies that can achieve these reductions. 
SmartWay partners have demonstrated these new and emerging technologies 
in their business operations, adding to the body of technical data and 
information that EPA can disseminate to industry, researchers and other 
stakeholders. Over the last several years, EPA has developed hands-on 
experience testing the largest heavy-duty trucks and trailers and 
evaluating improvements in tire and vehicle aerodynamic performance. In 
developing the Phase 1 program, the agencies drew from this testing and 
from the SmartWay experience. In the same way, the agencies benefitted 
from SmartWay in developing the proposed Phase 2 trailer program.
(d) The State of California
    California has established ambitious goals for reducing GHG 
emissions from heavy-duty vehicles and engines as part of an overall 
plan to reduce GHG emissions from the transportation sector in 
California.\30\ Heavy-duty vehicles are responsible for one-fifth of 
the total GHG emissions from transportation sources in California. In 
the past several years the California Air Resources Board (CARB) has 
taken a number of actions to reduce GHG emissions from heavy-duty 
vehicles and engines. For example, in 2008, the CARB adopted 
regulations to reduce GHG emissions from heavy-duty tractors that pull 
box-type trailers through improvements in tractor and trailer 
aerodynamics and the use of low rolling resistance tires.\31\ The 
tractors and trailers subject to the CARB regulation are required to 
use SmartWay certified tractors and trailers, or retrofit their 
existing fleet with SmartWay verified technologies, consistent with 
California's state authority to regulate both new and in-use vehicles. 
Recently, in December 2013, CARB adopted regulations that establish its 
own parallel Phase 1 program with standards consistent with EPA Phase 1 
standards. On December 5, 2014, California's Office of Administrative 
Law approved CARB's adoption of the Phase 1 standards, with an 
effective date of December 5, 2014.\32\ Complementary to its regulatory 
efforts, CARB and other California agencies are investing significant 
public capital through various incentive programs to accelerate fleet 
turnover and stimulate technology innovation within the heavy-duty 
vehicle market (e.g., Air Quality Improvement, Carl Moyer, Loan 
Incentives, Lower-Emission School Bus and Goods Movement Emission 
Reduction Programs).\33\ And, recently, California Governor Jerry Brown 
established a target of up to 50 percent petroleum reduction by 2030.
---------------------------------------------------------------------------

    \30\ See http://www.arb.ca.gov/cc/cc.htm for details on the 
California Air Resources Board climate change actions, including a 
discussion of Assembly Bill 32, and the Climate Change Scoping Plan 
developed by CARB, which includes details regarding CARB's future 
goals for reducing GHG emissions from heavy-duty vehicles.
    \31\ See http://www.arb.ca.gov/msprog/truckstop/trailers/trailers.htm for a summary of CARB's ``Tractor-Trailer Greenhouse 
Gas Regulation''.
    \32\ See http://www.arb.ca.gov/regact/2013/hdghg2013/hdghg2013.htm for details regarding CARB's adoption of the Phase 1 
standards.
    \33\ See http://www.arb.ca.gov/ba/fininfo.htm for detailed 
descriptions of CARB's mobile source incentive programs. Note that 
EPA works to support CARB's heavy-duty incentive programs through 
the West Coast Collaborative (http://westcoastcollaborative.org/) 
and the Clean Air Technology Initiative (http://www.epa.gov/region09/cleantech/).
---------------------------------------------------------------------------

    In addition to California's efforts to reduce GHG emissions that 
contribute to climate change, California also faces unique air quality 
challenges as compared to many other regions of the United States. Many 
areas of the state are classified as non-attainment for both the ozone 
and particulate matter National Ambient Air Quality Standards (NAAQS) 
with California having the nation's only two ``Extreme'' ozone non-
attainment airsheds (the San Joaquin Valley and South Coast Air 
Basins).\34\ By 2016, California must submit to EPA its Clean Air Act 
State Implementation Plans (SIPs) that demonstrate how the 2008 ozone 
and 2006 PM2.5 NAAQS will be met by Clean Air Act deadlines. 
Extreme ozone areas must attain the 2008 ozone NAAQS by no later than 
2032 and PM2.5 moderate areas must attain the 2006 
PM2.5 standard by 2021 or, if reclassified to serious, by 
2025.
---------------------------------------------------------------------------

    \34\ See http://www.epa.gov/airquality/greenbk/index.html for 
more information on EPA's nonattainment designations.
---------------------------------------------------------------------------

    Heavy-duty vehicles are responsible today for one-third of the 
state's oxides of nitrogen (NOX) emissions. California has 
estimated that the state's South Coast Air Basin will need nearly a 90 
percent reduction in heavy-duty vehicle NOX emissions by 
2032 from 2010 levels to attain the 2008 NAAQS for ozone. Additionally, 
on November 25, 2014, EPA issued a proposal to strengthen the ozone 
NAAQS. If a change to the ozone NAAQS is finalized, California and 
other areas of the country will need to identify and implement measures 
to reduce NOX as needed to complement Federal emission 
reduction measures. While this section is focused on California's 
regulatory programs and air quality needs, EPA recognizes that other 
states and local areas are concerned about the challenges of reducing 
NOX and attaining, as well as maintaining, the ozone NAAQS 
(further discussed in Section VIII.D.1 below).
    In order to encourage the use of lower NOX emitting new 
heavy-duty vehicles in California, in 2013 CARB adopted a voluntary low 
NOX emission standard for heavy-duty engines.\35\ In 
addition, in 2013 CARB awarded a major new research contract to 
Southwest Research Institute to investigate advanced technologies that 
could reduce heavy-duty vehicle NOX emissions well below the 
current EPA and CARB standards.
---------------------------------------------------------------------------

    \35\ See http://www.arb.ca.gov/regact/2013/hdghg2013/hdghg2013.htm for a description of the CARB optional reduced 
NOX emission standards for on-road heavy-duty engines.
---------------------------------------------------------------------------

    California has long had the unique ability among states to adopt 
its own separate new motor vehicle standards per Section 209 of the 
Clean Air Act (CAA). Although section 209(a) of the CAA expressly 
preempts states from adopting and enforcing standards relating to the 
control of emissions from new motor vehicles or new motor vehicle 
engines (such as state controls for new heavy-duty engines and 
vehicles) CAA section 209(b) directs EPA to waive this preemption under 
certain conditions. Under the waiver process set out in CAA Section 
209(b), EPA has granted CARB a waiver for its initial heavy-duty 
vehicle GHG regulation.\36\ Even with California's ability under the 
CAA to establish its own emission standards, EPA and CARB have worked 
closely together over the past several decades to largely harmonize new 
vehicle criteria pollutant standard programs for heavy-duty engines and 
heavy-duty vehicles. In the past several years EPA and NHTSA also 
consulted with CARB in the development of the Federal light-duty 
vehicle GHG and CAFE rulemakings for the 2012-2016 and 2017-2025 model 
years.
---------------------------------------------------------------------------

    \36\ See EPA's waiver of CARB's heavy-duty tractor-trailer 
greenhouse gas regulation applicable to new 2011 through 2013 model 
year Class 8 tractors equipped with integrated sleeper berths 
(sleeper-cab tractors) and 2011 and subsequent model year dry-can 
and refrigerated-van trailers that are pulled by such tractors on 
California highways at 79 FR 46256 (August 7, 2014).
---------------------------------------------------------------------------

    As discussed above, California operates under state authority to 
establish its own new heavy-duty vehicle and engine emission standards, 
including standards for CO2, methane, N2O, and 
hydrofluorocarbons. EPA recognizes this independent authority, and we 
also recognize the potential

[[Page 40150]]

benefits for the regulated industry if the Federal Phase 2 standards 
could result in a single, National Program that would meet the NHTSA 
and EPA's statutory requirements to set appropriate and maximum 
feasible standards, and also be equivalent to potential future new 
heavy-duty vehicle and engine GHG standards established by CARB 
(addressing the same model years as addressed by the final Federal 
Phase 2 program and requiring the same technologies).
    Similarly, CARB has expressed support in the past for a Federal 
heavy-duty Phase 2 program that would produce significant GHG 
reductions both at the Federal level and in California that could 
enable CARB to adopt the same standards at the state level. This is 
similar to CARB's approach for the Federal heavy-duty Phase 1 program, 
and with past EPA criteria pollutant standards for heavy-duty vehicles 
and engines. In order to further the opportunity for maintaining 
coordinated Federal and California standards in the Phase 2 timeframe 
(as well as to benefit from different technical expertise and 
perspective), NHTSA and EPA have consulted on an on-going basis with 
CARB over the past two years as we have developed the Phase 2 proposal. 
The agencies' technical staff have shared information on technology 
cost, technology effectiveness, and feasibility with the CARB staff. We 
have also received information from CARB on these same topics. EPA and 
NHTSA have also shared preliminary results from several of our modeling 
exercises with CARB as we examined different potential levels of 
stringency for the Phase 2 program. In addition, CARB staff and 
managers have also participated with EPA and NHTSA in meetings with 
many external stakeholders, in particular with vehicle OEMs and 
technology suppliers.
    In addition to information on GHG emissions, CARB has also kept EPA 
and NHTSA informed of the state's need to consider opportunities for 
additional NOX emission reductions from heavy-duty vehicles. 
CARB has asked the agencies to consider opportunities in the Heavy-Duty 
Phase 2 rulemaking to encourage or incentivize further NOX 
emission reductions, in addition to the petroleum and GHG reductions 
which would come from the Phase 2 standards. When combined with the 
Phase 1 standards, the technologies the agencies are projecting to be 
used to meet the proposed GHG emission and fuel efficiency standards 
would be expected to reduce NOX emissions by over 450,000 
tons in 2050 (see Section VIII).
    EPA and NHTSA believe that through this information sharing and 
dialog we will enhance the potential for the Phase 2 program to result 
in a National Program that can be adopted not only by the Federal 
agencies, but also by the State of California, given the strong 
interest from the regulated industry for a harmonized State and Federal 
program.
    The agencies will continue to seek input from CARB, and from all 
stakeholders, throughout this rulemaking.
(e) Environment Canada
    On March 13, 2013, Environment Canada (EPA's Canadian counterpart) 
published its own regulations to control GHG emissions from heavy-duty 
vehicles and engines, beginning with MY 2014. These regulations are 
closely aligned with EPA's Phase 1 program to achieve a common set of 
North American standards. Environment Canada has expressed its 
intention to amend these regulations to further limit emissions of 
greenhouse gases from new on-road heavy-duty vehicles and their engines 
for post-2018 MYs. As with the development of the current regulations, 
Environment Canada is committed to continuing to work closely with EPA 
to maintain a common Canada-United States approach to regulating GHG 
emissions for post-2018 MY vehicles and engines. This approach will 
build on the long history of regulatory alignment between the two 
countries on vehicle emissions pursuant to the Canada-United States Air 
Quality Agreement.\37\ Environment Canada has also been of great 
assistance during the development of this Phase 2 proposal. In 
particular, Environment Canada supported aerodynamic testing, and 
conducted chassis dynamometer emissions testing.
---------------------------------------------------------------------------

    \37\ http://www.ijc.org/en_/Air_Quality__Agreement.
---------------------------------------------------------------------------

(f) Recommendations of the National Academy of Sciences
    In April 2010 as mandated by Congress in the Energy Independence 
and Security Act of 2007 (EISA), the National Research Council (NRC) 
under the National Academy of Sciences (NAS) issued a report to NHTSA 
and to Congress evaluating medium- and heavy-duty truck fuel efficiency 
improvement opportunities, titled ``Technologies and Approaches to 
Reducing the Fuel Consumption of Medium- and Heavy-duty Vehicles.'' 
That NAS report was far reaching in its review of the technologies that 
were available and that might become available in the future to reduce 
fuel consumption from medium- and heavy-duty vehicles. In presenting 
the full range of technical opportunities, the report included 
technologies that may not be available until 2020 or even further into 
the future. The report provided not only a valuable list of off the 
shelf technologies from which the agencies drew in developing the Phase 
1 program, but also provided useful information the agencies have 
considered when developing this second phase of regulations.
    In April 2014, the NAS issued another report: ``Reducing the Fuel 
Consumption and Greenhouse Gas Emissions of Medium and Heavy-Duty 
Vehicles, Phase Two, First Report.'' This study outlines a number of 
recommendations to the U.S. Department of Transportation and NHTSA on 
technical and policy matters to consider when addressing the fuel 
efficiency of our nation's medium- and heavy-duty vehicles. In 
particular, this report provided recommendations with respect to:

 The Greenhouse Gas Emission Model (GEM) simulation tool used 
by the agencies to assess compliance with vehicle standards
 Regulation of trailers
 Natural gas-fueled engines and vehicles
 Data collection on in-use operation

    As described in Sections II, IV, and XII, the agencies are 
proposing to incorporate many of these recommendations into this 
proposed Phase 2 program, especially those recommendations relating to 
the GEM simulation tool and to trailers.

B. Summary of Phase 1 Program

(1) EPA Phase 1 GHG Emission Standards and NHTSA Phase 1 Fuel 
Consumption Standards
    The EPA Phase 1 GHG mandatory standards commenced in MY 2014 and 
include increased stringency for standards applicable to MY 2017 and 
later MY vehicles and engines. NHTSA's fuel consumption standards are 
voluntary for MYs 2014 and 2015, due to lead time requirements in EISA, 
and apply on a mandatory basis thereafter. They also increase in 
stringency for MY 2017. Both agencies have allowed voluntary early 
compliance starting in MY 2013 and encouraged manufacturers' 
participation through credit incentives.
    Given the complexity of the heavy-duty industry, the agencies 
divided the industry into three discrete categories for purposes of 
setting our respective Phase 1 standards--combination

[[Page 40151]]

tractors, heavy-duty pickups and vans, and vocational vehicles--based 
on the relative degree of homogeneity among trucks within each 
category. The Phase 1 rule also include separate standards for the 
engines that power combination tractors and vocational vehicles. For 
each regulatory category, the agencies adopted related but distinct 
program approaches reflecting the specific challenges in these 
segments. In the following paragraphs, we summarize briefly EPA's final 
GHG emission standards and NHTSA's final fuel consumption standards for 
the three regulatory categories of heavy-duty vehicles and for the 
engines powering vocational vehicles and tractors. See Sections III, V, 
and VI for additional details on the Phase 1 standards. To respect 
differences in design and typical uses that drive different technology 
solutions, the agencies segmented each regulatory class into 
subcategories. The category-specific structure enabled the agencies to 
set standards that appropriately reflect the technology available for 
each regulatory subcategory of vehicles and the engines for use in each 
type of vehicle. The Phase 1 program also provided several 
flexibilities, as summarized in Section I.B(3).
    The agencies are proposing to base the Phase 2 standards on test 
procedures that differ from those used for Phase 1, including the 
revised GEM simulation tool. Significant revisions to GEM are discussed 
in Section II and the draft RIA Chapter 4, and other test procedures 
are discussed further in the draft RIA Chapter 3. It is important to 
note that due to these test procedure changes, the Phase 1 standards 
and the proposed Phase 2 standards are not directly comparable in an 
absolute sense. In particular, the proposed revisions to the 55 mph and 
65 mph highway cruise cycles for tractors and vocational vehicles have 
the effect of making the cycles more challenging (albeit more 
representative of actual driving conditions). We are not proposing to 
apply these revisions to the Phase 1 program because doing so would 
significantly change the stringency of the Phase 1 standards, for which 
manufacturers have already developed engineering plans and are now 
producing products to meet. Moreover, the agencies intend such changes 
to address a broader range of technologies not part of the projected 
compliance path for use in Phase 1.
(a) Class 7 and 8 Combination Tractors
    Class 7 and 8 combination tractors and their engines contribute the 
largest portion of the total GHG emissions and fuel consumption of the 
heavy-duty sector, approximately two-thirds, due to their large 
payloads, their high annual miles traveled, and their major role in 
national freight transport. These vehicles consist of a cab and engine 
(tractor or combination tractor) and a detachable trailer. The primary 
manufacturers of combination tractors in the United States are Daimler 
Trucks North America, Navistar, Volvo/Mack, and PACCAR. Each of the 
tractor manufacturers and Cummins (an independent engine manufacturer) 
also produce heavy-duty engines used in tractors. The Phase 1 standards 
require manufacturers to reduce GHG emissions and fuel consumption for 
these vehicles and engines, which we expect them to do through 
improvements in aerodynamics and tires, reductions in tractor weight, 
reduction in idle operation, as well as engine-based efficiency 
improvements.\38\
---------------------------------------------------------------------------

    \38\ We note although the standards' stringency is predicated on 
use of certain technologies, and the agencies' assessed the cost of 
the rule based on the cost of use of those technologies, the 
standards can be met by any means. Put another way, the rules create 
a performance standard, and do not mandate any particular means of 
achieving that level of performance.
---------------------------------------------------------------------------

    The Phase 1 tractor standards differ depending on gross vehicle 
weight rating (GVWR) (i.e., whether the truck is Class 7 or Class 8), 
the height of the roof of the cab, and whether it is a ``day cab'' or a 
``sleeper cab.'' The agencies created nine subcategories within the 
Class 7 and 8 combination tractor category reflecting combinations of 
these attributes. The agencies set Phase 1 standards for each of these 
subcategories beginning in MY 2014, with more stringent standards 
following in MY 2017. The standards represent an overall fuel 
consumption and CO2 emissions reduction up to 23 percent 
from the tractors and the engines installed in them when compared to a 
baseline MY 2010 tractor and engine.
    For Phase 1, manufacturers demonstrate compliance with the tractor 
CO2 and fuel consumption standards using a vehicle 
simulation tool described in Section II. The tractor inputs to the 
simulation tool in Phase 1 are the aerodynamic performance, tire 
rolling resistance, vehicle speed limiter, automatic engine shutdown, 
and weight reduction. The agencies have verified, through our own 
confirmatory testing, that the values inputs into the model by 
manufacturers are generally correct. Prior to and after adopting the 
Phase 1 standards, the agencies worked with manufacturers to minimize 
impacts of this process on their normal business practices.
    In addition to the final Phase 1 tractor-based standards for 
CO2, EPA adopted a separate standard to reduce leakage of 
hydrofluorocarbon (HFC) refrigerant from cabin air conditioning (A/C) 
systems from combination tractors, to apply to the tractor 
manufacturer. This HFC leakage standard is independent of the 
CO2 tractor standard. Manufacturers can choose technologies 
from a menu of leak-reducing technologies sufficient to comply with the 
standard, as opposed to using a test to measure performance. Given that 
HFC leakage does not relate to fuel efficiency, NHTSA did not adopt 
corresponding HFC standards.
(b) Heavy-Duty Pickup Trucks and Vans (Class 2b and 3)
    Heavy-duty vehicles with a GVWR between 8,501 and 10,000 lb are 
classified as Class 2b motor vehicles. Heavy-duty vehicles with a GVWR 
between 10,001 and 14,000 lb are classified as Class 3 motor vehicles. 
Class 2b and Class 3 heavy-duty vehicles (referred to in these rules as 
``HD pickups and vans'') together emit about 15 percent of today's GHG 
emissions from the heavy-duty vehicle sector.\39\
---------------------------------------------------------------------------

    \39\ EPA MOVES Model, http://www.epa.gov/otaq/models/moves/index.htm.
---------------------------------------------------------------------------

    The majority of HD pickups and vans are \3/4\-ton and 1-ton pickup 
trucks, 12- and 15-passenger vans,\40\ and large work vans that are 
sold by vehicle manufacturers as complete vehicles, with no secondary 
manufacturer making substantial modifications prior to registration and 
use. These vehicles can also be sold as cab-complete vehicles (i.e., 
incomplete vehicles that include complete or nearly complete cabs that 
are sold to secondary manufacturers). The majority of heavy-duty 
pickups and vans are produced by companies with major light-duty 
markets in the United States. Furthermore, the technologies available 
to reduce fuel consumption and GHG emissions from this segment are 
similar to the technologies used on light-duty pickup trucks, including 
both engine efficiency improvements (for gasoline and diesel engines) 
and vehicle efficiency improvements. For these reasons, EPA and NHTSA 
concluded that it was appropriate to adopt GHG standards, expressed as 
grams per mile, and fuel consumption standards, expressed as gallons 
per 100 miles, for HD pickups and vans based on the whole vehicle 
(including the engine), consistent with the way these vehicles

[[Page 40152]]

have been regulated by EPA for criteria pollutants and also consistent 
with the way their light-duty counterpart vehicles are regulated by 
NHTSA and EPA. This complete vehicle approach adopted by both agencies 
for HD pickups and vans was consistent with the recommendations of the 
NAS Committee in its 2010 Report.
---------------------------------------------------------------------------

    \40\ Note that 12-passenger vans are subject to the light-duty 
standards as medium-duty passenger vehicles (MDPVs) and are not 
subject to this proposal.
---------------------------------------------------------------------------

    For the light-duty GHG and fuel economy standards, the agencies 
based the emissions and fuel economy targets on vehicle footprint (the 
wheelbase times the average track width). For those standards, 
passenger cars and light trucks with larger footprints are assigned 
higher GHG and lower fuel economy target levels reflecting their 
inherent tendency to consume more fuel and emit more GHGs per mile. For 
HD pickups and vans, the agencies believe that setting standards based 
on vehicle attributes is appropriate, but have found that a work-based 
metric would be a more appropriate attribute than the footprint 
attribute utilized in the light-duty vehicle rulemaking, given that 
work-based measures such as towing and payload capacities are critical 
elements of these vehicles' functionality. EPA and NHTSA therefore 
adopted standards for HD pickups and vans based on a ``work factor'' 
attribute that combines their payload and towing capabilities, with an 
added adjustment for 4-wheel drive vehicles.
    Each manufacturer's fleet average Phase 1 standard is based on 
production volume-weighting of target standards for all vehicles, which 
in turn are based on each vehicle's work factor. These target standards 
are taken from a set of curves (mathematical functions), with separate 
curves for gasoline and diesel.\41\ However, both gasoline and diesel 
vehicles in this category are included in a single averaging set. EPA 
phased in the CO2 standards gradually starting in the 2014 
MY, at 15-20-40-60-100 percent of the MY 2018 standards stringency 
level in MYs 2014-2015-2016-2017-2018, respectively. The phase-in takes 
the form of a set of target curves, with increasing stringency in each 
MY.
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    \41\ As explained in Section XII, EPA is proposing to recodify 
the Phase 1 requirements for pickups and vans from 40 CFR 1037.104 
into 40 CFR part 86, which is also the regulatory part that applies 
for light-duty vehicles.
---------------------------------------------------------------------------

    NHTSA allowed manufacturers to select one of two fuel consumption 
standard alternatives for MYs 2016 and later. The first alternative 
defined individual gasoline vehicle and diesel vehicle fuel consumption 
target curves that will not change for MYs 2016-2018, and are 
equivalent to EPA's 67-67-67-100 percent target curves in MYs 2016-
2017-2018-2019, respectively. The second alternative defined target 
curves that are equivalent to EPA's 40-60-100 percent target curves in 
MYs 2016-2017-2018, respectively. NHTSA allowed manufacturers to opt 
voluntarily into the NHTSA HD pickup and van program in MYs 2014 or 
2015 at target curves equivalent to EPA's target curves. If a 
manufacturer chose to opt in for one category, they would be required 
to opt in for all categories. In other words a manufacturer would be 
unable to opt in for Class 2b vehicles, but opt out for Class 3 
vehicles.
    EPA also adopted an alternative phase-in schedule for manufacturers 
wanting to have stable standards for model years 2016-2018. The 
standards for heavy-duty pickups and vans, like those for light-duty 
vehicles, are expressed as set of target standard curves, with 
increasing stringency in each model year. The final EPA standards for 
2018 (including a separate standard to control air conditioning system 
leakage) represent an average per-vehicle reduction in GHG emissions of 
17 percent for diesel vehicles and 12 percent for gasoline vehicles 
(relative to pre-control baseline vehicles). The NHTSA standard will 
require these vehicles to achieve up to about 15 percent reduction in 
fuel consumption and greenhouse gas emissions by MY 2018 (relative to 
pre-control baseline vehicles). Manufacturers demonstrate compliance 
based on entire vehicle chassis certification using the same duty 
cycles used to demonstrate compliance with criteria pollutant 
standards.
(c) Class 2b-8 Vocational Vehicles
    Class 2b-8 vocational vehicles include a wide variety of vehicle 
types, and serve a vast range of functions. Some examples include 
service for urban delivery, refuse hauling, utility service, dump, 
concrete mixing, transit service, shuttle service, school bus, 
emergency, motor homes, and tow trucks. In Phase 1, we defined Class 
2b-8 vocational vehicles as all heavy-duty vehicles that are not 
included in either the heavy-duty pickup and van category or the Class 
7 and 8 tractor category. EPA's and NHTSA's Phase 1 standards for this 
vocational vehicle category generally apply at the chassis manufacturer 
level. Class 2b-8 vocational vehicles and their engines emit 
approximately 20 percent of the GHG emissions and burn approximately 21 
percent of the fuel consumed by today's heavy-duty truck sector.\42\
---------------------------------------------------------------------------

    \42\ EPA MOVES model, http://www.epa.gov/otaq/models/moves/index.htm.
---------------------------------------------------------------------------

    The Phase 1 program for vocational vehicles has vehicle standards 
and separate engine standards, both of which differ based on the weight 
class of the vehicle into which the engine will be installed. The 
vehicle weight class groups mirror those used for the engine 
standards--Classes 2b-5 (light heavy-duty or LHD in EPA regulations), 
Classes 6 & 7 (medium heavy-duty or MHD in EPA regulations) and Class 8 
(heavy heavy-duty or HHD in EPA regulations). Manufacturers demonstrate 
compliance with the Phase 1 vocational vehicle CO2 and fuel 
consumption standards using a vehicle simulation tool described in 
Section II. The Phase 1 program for vocational vehicles limited the 
simulation tool inputs to tire rolling resistance. The model assumes 
the use of a typical representative, compliant engine in the 
simulation, resulting in one overall value for CO2 emissions 
and one for fuel consumption.
    Engines used in vocational vehicles are subject to separate Phase 1 
engine-based standards. Optional certification paths, for EPA and 
NHTSA, are also provided to enhance the flexibilities for vocational 
vehicles. Manufacturers producing spark-ignition (or gasoline) cab-
complete or incomplete vehicles weighing over 14,000 lbs GVWR and below 
26,001 lbs GVWR have the option to certify to the complete vehicle 
standards for heavy-duty pickup trucks and vans rather than using the 
separate engine and chassis standards for vocational vehicles.
(d) Engine Standards
    The agencies established separate Phase 1 performance standards for 
the engines manufactured for use in vocational vehicles and Class 7 and 
8 tractors.\43\ These engine standards vary depending on engine size 
linked to intended vehicle service class. EPA's engine-based 
CO2 standards and NHTSA's engine-based fuel consumption 
standards are being implemented using EPA's existing test procedures 
and regulatory structure for criteria pollutant emissions from heavy-
duty engines.
---------------------------------------------------------------------------

    \43\ See 76 FR 57114 explaining why NHTSA's authority under the 
Energy Independence and Safety Act includes authority to establish 
separate engine standards.
---------------------------------------------------------------------------

    The agencies also finalized a regulatory alternative whereby a 
manufacturer, for an interim period of the 2014-2016 MYs, would have 
the option to comply with a unique standard based on a three percent 
reduction from an individual engine model's own 2011 MY baseline 
level.\44\
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    \44\ See 76 FR 57144.

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[[Page 40153]]

(e) Manufacturers Excluded From the Phase 1 Standards
    Phase 1 temporarily deferred greenhouse gas emissions and fuel 
consumption standards for any manufacturers of heavy-duty engines, 
manufacturers of combination tractors, and chassis manufacturers for 
vocational vehicles that meet the ``small business'' size criteria set 
by the Small Business Administration (SBA). 13 CFR 121.201 defines a 
small business by the maximum number of employees; for example, this is 
currently 1,000 for heavy-duty vehicle manufacturing and 750 for engine 
manufacturing. In order to utilize this exemption, qualifying small 
businesses must submit a declaration to the agencies. See Section 
I.F.(1)(b) for a summary of how Phase 2 would apply for small 
businesses.
    The agencies stated that they would consider appropriate GHG and 
fuel consumption standards for these entities as part of a future 
regulatory action. This includes both U.S.-based and foreign small-
volume heavy-duty manufacturers.
(2) Costs and Benefits of the Phase 1 Program
    Overall, EPA and NHTSA estimated that the Phase 1 HD National 
Program will cost the affected industry about $8 billion, while saving 
vehicle owners fuel costs of nearly $50 billion over the lifetimes of 
MY 2014-2018 vehicles. The agencies also estimated that the combined 
standards will reduce CO2 emissions by about 270 million 
metric tons and save about 530 million barrels of oil over the life of 
MY 2014 to 2018 vehicles. The agencies estimated additional monetized 
benefits from CO2 reductions, improved energy security, 
reduced time spent refueling, as well as possible disbenefits from 
increased driving accidents, traffic congestion, and noise. When 
considering all these factors, we estimated that Phase 1 of the HD 
National Program will yield $49 billion in net benefits to society over 
the lifetimes of MY 2014-2018 vehicles.
    EPA estimated the benefits of reduced ambient concentrations of 
particulate matter and ozone resulting from the Phase 1 program to 
range from $1.3 to $4.2 billion in 2030.\45\
---------------------------------------------------------------------------

    \45\ Note: These calendar year benefits do not represent the 
same time frame as the model year lifetime benefits described above, 
so they are not additive.
---------------------------------------------------------------------------

    In total, we estimated the combined Phase 1 standards will reduce 
GHG emissions from the U.S. heavy-duty fleet by approximately 76 
million metric tons of CO2-equivalent annually by 2030. In 
its Environmental Impact Statement for the Phase 1 rule, NHTSA also 
quantified and/or discussed other potential impacts of the program, 
such as the health and environmental impacts associated with changes in 
ambient exposures to toxic air pollutants and the benefits associated 
with avoided non-CO2 GHGs (methane, nitrous oxide, and 
HFCs).
(3) Phase 1 Program Flexibilities
    As noted above, the agencies adopted numerous provisions designed 
to give manufacturers a degree of flexibility in complying with the 
Phase 1 standards. These provisions, which are essentially identical in 
structure and function in NHTSA's and EPA's regulations, enabled the 
agencies to consider overall standards that are more stringent and that 
will become effective sooner than we could consider with a more rigid 
program, one in which all of a manufacturer's similar vehicles or 
engines would be required to achieve the same emissions or fuel 
consumption levels, and at the same time.\46\
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    \46\ NHTSA explained that it has greater flexibility in the HD 
program to include consideration of credits and other flexibilities 
in determining appropriate and feasible levels of stringency than it 
does in the light-duty CAFE program. Cf. 49 U.S.C. 32902(h), which 
applies to light-duty CAFE but not heavy-duty fuel efficiency under 
49 U.S.C. 32902(k).
---------------------------------------------------------------------------

    Phase 1 included four primary types of flexibility: Averaging, 
banking, and trading (ABT) provisions; early credits; advanced 
technology credits (including hybrid powertrains); and innovative 
technology credit provisions. The ABT provisions were patterned on 
existing EPA and NHTSA ABT programs (including the light-duty GHG and 
fuel economy standards) and will allow a vehicle manufacturer to reduce 
CO2 emission and fuel consumption levels further than the 
level of the standard for one or more vehicles to generate ABT credits. 
The manufacturer can use those credits to offset higher emission or 
fuel consumption levels in the same averaging set, ``bank'' the credits 
for later use, or ``trade'' the credits to another manufacturer. As 
also noted above, for HD pickups and vans, we adopted a fleet averaging 
system very similar to the light-duty GHG and CAFE fleet averaging 
system. In both programs, manufacturers are allowed to carry-forward 
deficits for up to three years without penalty.
    The agencies provided in the ABT programs flexibility for 
situations in which a manufacturer is unable to avoid a negative credit 
balance at the end of the year. In such cases, manufacturers are not 
considered to be out of compliance unless they are unable to make up 
the difference in credits by the end of the third subsequent model 
year.
    In total, the Phase 1 program divides the heavy-duty sector into 19 
subcategories of vehicles. These subcategories are grouped into 9 
averaging sets to provide greater opportunities in leveraging 
compliance. For tractors and vocational vehicles, the fleet averaging 
sets are Classes 2b through 5, Classes 6 and 7, and Class 8 weight 
classes. For engines, the fleet averaging sets are gasoline engines, 
light heavy-duty diesel engines, medium heavy-duty diesel engines, and 
heavy heavy-duty diesel engines. Complete HD pickups and vans (both 
spark-ignition and compression-ignition) are the final fleet averaging 
set.
    As noted above, the agencies included a restriction on averaging, 
banking, and trading of credits between the various regulatory 
subcategories by defining three HD vehicle averaging sets: Light heavy-
duty (Classes 2b-5); medium heavy-duty (Class 6-7); and heavy heavy-
duty (Class 8). This allows the use of credits between vehicles within 
the same weight class. This means that a Class 8 day cab tractor can 
exchange credits with a Class 8 high roof sleeper tractor but not with 
a smaller Class 7 tractor. Also, a Class 8 vocational vehicle can 
exchange credits with a Class 8 tractor. However, we did not allow 
trading between engines and chassis. We similarly allowed for trading 
among engine categories only within an averaging set, of which there 
are four: Spark-ignition engines, compression-ignition light heavy-duty 
engines, compression-ignition medium heavy-duty engines, and 
compression-ignition heavy heavy-duty engines.
    In addition to ABT, the other primary flexibility provisions in the 
Phase 1 program involve opportunities to generate early credits, 
advanced technology credits (including for use of hybrid powertrains), 
and innovative technology credits.\47\ For the early credits and 
advanced technology credits, the agencies adopted a 1.5 x multiplier, 
meaning that manufacturers would get 1.5 credits for each early credit 
and each advanced technology credit. In addition, advanced technology 
credits for Phase 1 can be used anywhere within the heavy-duty sector 
(including both vehicles and engines). Put another way, as a means of 
promoting this promising technology,

[[Page 40154]]

the Phase 1 rule does not restrict averaging or trading by averaging 
set in this instance.
---------------------------------------------------------------------------

    \47\ Early credits are for engines and vehicles certified before 
EPA standards became mandatory, advanced technology credits are for 
hybrids and/or Rankine cycle engines, and innovative technology 
credits are for other technologies not in the 2010 fleet whose 
benefits are not reflected using the Phase 1 test procedures.
---------------------------------------------------------------------------

    For other vehicle or engine technologies that can reduce 
CO2 and fuel consumption, but for which there do not yet 
exist established methods for quantifying reductions, the agencies 
wanted to encourage the development of such innovative technologies, 
and therefore adopted special ``innovative technology'' credits. These 
innovative technology credits apply to technologies that are shown to 
produce emission and fuel consumption reductions that are not 
adequately recognized on the Phase 1 test procedures and that were not 
yet in widespread use in the heavy-duty sector before MY 2010. 
Manufacturers need to quantify the reductions in fuel consumption and 
CO2 emissions that the technology is expected to achieve, 
above and beyond those achieved on the existing test procedures. As 
with ABT, the use of innovative technology credits is allowed only 
among vehicles and engines of the same defined averaging set generating 
the credit, as described above. The credit multiplier likewise does not 
apply for innovative technology credits.
(4) Implementation of Phase 1
    Manufacturers have already begun complying with the Phase 1 
standards. In some cases manufacturers voluntarily chose to comply 
early, before compliance was mandatory. The Phase 1 rule allows 
manufacturers to generate credits for such early compliance. The market 
appears to be very accepting of the new technology, and the agencies 
have seen no evidence of ``pre-buy'' effects in response to the 
standards. In fact sales have been higher in recent years than they 
were before Phase 1 began. Moreover, manufacturers' compliance plans 
are taking advantage of the Phase 1 flexibilities, and we have yet to 
see significant non-compliance with the standards.
(5) Litigation on Phase 1 Rule
    The D.C. Circuit recently rejected all challenges to the agencies' 
Phase 1 regulations. The court did not reach the merits of the 
challenges, holding that none of the petitioners had standing to bring 
their actions, and that a challenge to NHTSA's denial of a rulemaking 
petition could only be brought in District Court. See Delta 
Construction Co. v. EPA, 783 F. 3d 1291 (D.C. Cir. 2015), U.S. App. 
LEXIS 6780, F.3d (D.C. Cir. April 24, 2015).

C. Summary of the Proposed Phase 2 Standards and Requirements

    The agencies are proposing new standards that build on and enhance 
existing Phase 1 standards, as well as proposing the first ever 
standards for certain trailers used in combination with heavy-duty 
tractors. Taken together, the proposed Phase 2 program would comprise a 
set of largely technology-advancing standards that would achieve 
greater GHG and fuel consumption savings than the Phase 1 program. As 
described in more detail in the following sections, the agencies are 
proposing these standards because, based on the information available 
at this time, we believe they would best match our respective statutory 
authorities when considered in the context of available technology, 
feasible reductions of emissions and fuel consumption, costs, lead 
time, safety, and other relevant factors. The agencies request comment 
on all aspects of our feasibility analysis including projections of 
feasible market adoption rates and technological effectiveness for each 
technology.
    The proposed Phase 2 standards would represent a more technology-
forcing \48\ approach than the Phase 1 approach, predicated on use of 
both off-the-shelf technologies and emerging technologies that are not 
yet in widespread use. The agencies are proposing standards for MY 2027 
that would likely require manufacturers to make extensive use of these 
technologies. For existing technologies and technologies in the final 
stages of development, we project that manufacturers would likely apply 
them to nearly all vehicles, excluding those specific vehicles with 
applications or uses that would prevent the technology from functioning 
properly. We also project as one possible compliance pathway that 
manufacturers could apply other more advanced technologies such as 
hybrids and waste engine heat recovery systems, although at lower 
application rates.
---------------------------------------------------------------------------

    \48\ In this context, the term ``technology-forcing'' is used to 
distinguish standards that will effectively require manufacturers to 
develop new technologies (or to significantly improve technologies) 
from standards that can be met using off-the-shelf technology alone. 
Technology-forcing standards do not require manufacturers to use any 
specific technologies.
---------------------------------------------------------------------------

    Under Alternative 3, the preferred alternative, the agencies 
propose to provide ten years of lead time for manufacturers to meet 
these 2027 standards, which the agencies believe is adequate to 
implement the technologies industry could use to meet the proposed 
standards. For some of the more advanced technologies production 
prototype parts are not yet available, though they are in the research 
stage with some demonstrations in actual vehicles.\49\ Additionally, 
even for the more developed technologies, phasing in more stringent 
standards over a longer timeframe may help manufacturers to ensure 
better reliability of the technology and to develop packages to work in 
a wide range of applications. Moving more quickly, however, as in 
Alternative 4, would lead to earlier and greater cumulative fuel 
savings and greenhouse gas reductions.
---------------------------------------------------------------------------

    \49\ ``Prototype'' as it is used here refers to technologies 
that have a potentially production-feasible design that is expected 
to meet all performance, functional, reliability, safety, 
manufacturing, cost and other requirements and objectives that is 
being tested in laboratories and on highways under a full range of 
operating conditions, but is not yet available in production 
vehicles already for sale in the market.
---------------------------------------------------------------------------

    As discussed later, the agencies are also proposing new standards 
in MYs 2018 (trailers only), 2021, and 2024 to ensure manufacturers 
make steady progress toward the 2027 standards, thereby achieving 
steady and feasible reductions in GHG emissions and fuel consumption in 
the years leading up to the MY 2027 standards. Moving more quickly, 
however, as in Alternative 4, would lead to earlier and greater 
cumulative fuel and greenhouse gas savings.
    Providing additional lead time can often enable manufacturers to 
resolve technological challenges or to find lower cost means of meeting 
new regulatory standards, effectively making them more feasible in 
either case. See generally NRDC v. EPA, 655 F. 2d 318, 329 (D.C. Cir. 
1981). On the other hand, manufacturers and/or operators may incur 
additional costs if regulations require them to make changes to their 
products with less lead time than manufacturers would normally have 
when bringing a new technology to the market or expanding the 
application of existing technologies. After developing a new 
technology, manufacturers typically conduct extensive field tests to 
ensure its durability and reliability in actual use. Standards that 
accelerate technology deployment can lead to manufacturers incurring 
additional costs to accelerate this development work, or can lead to 
manufacturers beginning production before such testing can be 
completed. Some industry stakeholders have informed EPA that when 
manufacturers introduced new emission control technologies (primarily 
diesel particulate filters) in response to the 2007 heavy-duty engine 
standards

[[Page 40155]]

they did not perform sufficient product development validation, which 
led to additional costs for operators when the technologies required 
repairs or other resulted in other operational issues in use. Thus, the 
issues of costs, lead time, and reliability are intertwined for the 
agencies' determination of whether standards are reasonable.
    Another important consideration is the possibility of disrupting 
the market, such as might happen if we were to adopt standards that 
manufacturers respond to by applying a new technology too suddenly. 
Several of the heavy-duty vehicle manufacturers, fleets, and commercial 
truck dealerships informed the agencies that for fleet purchases that 
are planned more than a year in advance, expectations of reduced 
reliability, increased operating costs, reduced residual value, or of 
large increases in purchase prices can lead the fleets to pull-ahead by 
several months planned future vehicle purchases by pre-buying vehicles 
without the newer technology. In the context of the Class 8 tractor 
market, where a relatively small number of large fleets typically 
purchase very large volumes of tractors, such actions by a small number 
of firms can result in large swings in sales volumes. Such market 
impacts would be followed by some period of reduced purchases that can 
lead to temporary layoffs at the factories producing the engines and 
vehicles, as well as at supplier factories, and disruptions at 
dealerships. Such market impacts also can reduce the overall 
environmental and fuel consumption benefits of the standards by 
delaying the rate at which the fleet turns over. See International 
Harvester v. EPA, 478 F. 2d 615, 634 (D.C. Cir. 1973). A number of 
industry stakeholders have informed EPA that the 2007 EPA heavy-duty 
engine criteria pollutant standard resulted in this pull-ahead 
phenomenon for the Class 8 tractor market. The agencies understand the 
potential impact that a pull-ahead can have on American manufacturing 
and labor, dealerships, truck purchasers, and on the program's 
environmental and fuel savings goals, and have taken steps in the 
design of the proposed program to avoid such disruption. These steps 
include the following:

 Providing considerable lead time, including two to three 
additional years for the preferred alternative compared to Alternative 
4
 The standards will result in significantly lower operating 
costs for vehicle owners (unlike the 2007 standard, which increased 
operating costs)
 Phasing in the standards
 Structuring the program so the industry will have a 
significant range of technology choices to be considered for 
compliance, rather than the one or two new technologies the OEMs 
pursued in 2007
 Allowing manufacturers to use emissions averaging, banking and 
trading to phase in the technology even further

    We request comment on the sufficiency of the proposed Phase 2 
structure, lead time, and stringency to avoid market disruptions. We 
note an important difference, however, between standards for criteria 
pollutants, with generally no attendant fuel savings, and the fuel 
consumption/GHG emission standards proposed today, which provide 
immediate and direct financial benefits to vehicle purchasers, who will 
begin saving money on fuel costs as soon as they begin operating the 
vehicles. It would seem logical, therefore, that vehicle purchasers 
(and manufacturers) would weigh those significant fuel savings against 
the potential for increased costs that could result from applying fuel-
saving technologies sooner than they might otherwise choose in the 
absence of the standards.
    As discussed in the Phase 1 final rule, NHTSA has certain statutory 
considerations to take into account when determining feasibility of the 
preferred alternative.\50\ The Energy Independence and Security Act 
(EISA) states that NHTSA (in consultation with EPA and the Secretary of 
Energy) shall develop a commercial medium- and heavy-duty fuel 
efficiency program designed ``to achieve the maximum feasible 
improvement.'' \51\ Although there is no definition of maximum feasible 
standards in EISA, NHTSA is directed to consider three factors when 
determining what the maximum feasible standards are. Those factors are, 
appropriateness, cost-effectiveness, and technological feasibility,\52\ 
which modify ``feasible'' beyond its plain meaning.
---------------------------------------------------------------------------

    \50\ 75 FR 57198.
    \51\ 49 U.S.C. 32902(k).
    \52\ Id.
---------------------------------------------------------------------------

    NHTSA has the broad discretion to weigh and balance the 
aforementioned factors in order to accomplish EISA's mandate of 
determining maximum feasible standards. The fact that the factors may 
often be at odds gives NHTSA significant discretion to decide what 
weight to give each of the competing factors, policies and concerns and 
then determine how to balance them--as long as NHTSA's balancing does 
not undermine the fundamental purpose of the EISA: Energy conservation, 
and as long as that balancing reasonably accommodates ``conflicting 
policies that were committed to the agency's care by the statute.'' 
\53\
---------------------------------------------------------------------------

    \53\ Center for Biological Diversity v. National Highway Traffic 
Safety Admin., 538 F.3d 1172, 1195 (9th Cir. 2008).
---------------------------------------------------------------------------

    EPA also has significant discretion in assessing, weighing, and 
balancing the relevant statutory criteria. Section 202(a)(2) of the 
Clean Air Act requires that the standards ``take effect after such 
period as the Administrator finds necessary to permit the development 
and application of the requisite technology, giving appropriate 
consideration to the cost of compliance within such period.'' This 
language affords EPA considerable discretion in how to weight the 
critical statutory factors of emission reductions, cost, and lead time 
(76 FR 57129-57130). Section 202(a) also allows (although it does not 
compel) EPA to adopt technology-forcing standards. Id. at 57130.
    Giving due consideration to the agencies' respective statutory 
criteria discussed above, the agencies are proposing these technology-
forcing standards for MY 2027. The agencies nevertheless recognize that 
there is some uncertainty in projecting costs and effectiveness, 
especially for those technologies not yet widely available, but believe 
that the thresholds proposed for consideration account for realistic 
projections of technological development discussed throughout this 
notice and in the draft RIA. The agencies are requesting comment on the 
alternatives described in Section X below. These alternatives range 
from Alternative 1 (which is a no-action alternative that serves as the 
baseline for our cost and benefit analyses) to Alternative 5 (which 
includes the most stringent of the alternative standards analyzed by 
the agencies). The assessment of these different alternatives considers 
the importance of allowing manufacturers sufficient flexibility and 
discretion while achieving meaningful fuel consumption and GHG 
emissions reductions across vehicle types. The agencies look forward to 
receiving comments on questions of feasibility and long-term 
projections of costs and effectiveness.
    As discussed throughout this document, the agencies believe 
Alternative 4 has potential to be the maximum feasible alternative, 
however, based on the evidence currently before us, the agencies have 
outstanding questions regarding relative risks and

[[Page 40156]]

benefits of that option in the timeframe envisioned. We are seeking 
comment on these relative risks and benefits. Alternative 3 is 
generally designed to achieve the vehicle levels of fuel consumption 
and GHG reduction that Alternative 4 would achieve, but with two to 
three years of additional lead-time--i.e., the Alternative 3 standards 
would end up in the same place as the Alternative 4 standards, but two 
to three years later, meaning that manufacturers could, in theory, 
apply new technology at a more gradual pace and with greater 
flexibility as discussed above. However, Alternative 4 would lead to 
earlier and greater cumulative fuel savings and greenhouse gas 
reductions.
    In the sections that follow, the agencies have closely examined the 
potential feasibility of Alternative 4 for each subcategory. The 
agencies may consider establishing final fuel efficiency and GHG 
standards in whole or in part in the Alternative 4 timeframe if we deem 
them to be maximum feasible and reasonable for NHTSA and EPA, 
respectively. The agencies seek comment on the feasibility of 
Alternative 4, whether for some or for all segments, including 
empirical data on its appropriateness, cost-effectiveness, and 
technological feasibility. The agencies also note the possibility of 
adoption in MY 2024 of a standard reflecting deployment of some, rather 
than all, of the technologies on which Alternative 4 is predicated. It 
is also possible that the agencies could adopt some or all of the 
proposal (Alternative 3) earlier than MY 2027, but later than MY 2024, 
based especially on lead time considerations. Any such choices would 
involve a considered weighing of the issues of feasibility of projected 
technology penetration rates, associated costs, and necessary lead 
time, and would consider the information on available technologies, 
their level of performance and costs set out in the administrative 
record to this proposal.
    Sections II through VI of this notice explain the consideration 
that the agencies took into account in considering options and 
proposing a preferred alternative based on balancing of the statutory 
factors under 42 U.S.C. 7521(a)(1) and (2), and under 49 U.S.C. 
32902(k).
(1) Carryover From Phase 1 Program and Proposed Compliance Changes
    Phase 2 will carry over many of the compliance approaches developed 
for Phase 1, with certain changes as described below. Readers are 
referred to the proposed regulatory text for much more detail. Note 
that some of these provisions are being carried over with revisions or 
additions (such as those needed to address trailers).
(a) Certification
    EPA and NHTSA are proposing to apply the same general certification 
procedures for Phase 2 as are currently being used for certifying to 
the Phase 1 standards. The agencies, however, are proposing changes to 
the simulation tool used for the vocational vehicle, tractor and 
trailer standards that would allow the simulation tool to more 
specifically reflect improvements to transmissions and drivetrains.\54\ 
Rather than the model using default values for transmissions and 
drivetrains, manufacturers would enter measured or tested values as 
inputs reflecting performance of their actual transmission and 
drivetrain technologies.
---------------------------------------------------------------------------

    \54\ As described in Section IV, although the proposed trailer 
standards were developed using the simulation tool, the agencies are 
proposing a compliance structure that does not require trailer 
manufacturers to actually use the compliance tool.
---------------------------------------------------------------------------

    The agencies apply essentially the same process for certifying 
tractors and vocational vehicles, and propose largely to apply it to 
trailers as well. The Phase 1 certification process for engines used in 
tractors and vocational vehicles was based on EPA's process for showing 
compliance with the heavy-duty engine criteria pollutant standards, and 
the agencies propose to continue it for Phase 2. Finally, we also 
propose to continue certifying HD pickups and vans using the Phase 1 
vehicle certification process, which is very similar to the light-duty 
vehicle certification process.
    EPA and NHTSA are also proposing to clarify provisions related to 
confirming a manufacturer's test data during certification (i.e., 
confirmatory testing) and verifying a manufacturer's vehicles are being 
produced to perform as described in the application for certification 
(i.e., selective enforcement audits or SEAs). The EPA confirmatory 
testing provisions for engines and vehicles are in 40 CFR 1036.235 and 
1037.235. The SEA provisions are in 40 CFR 1036.301 and 1037.301. The 
NHTSA provisions are in 49 CFR 535.9(a). Note that these clarifications 
would also apply for Phase 1 engines and vehicles. The agencies welcome 
suggestions for alternative approaches that would offer the same degree 
of compliance assurance for GHGs and fuel consumption as these programs 
offer with respect to EPA's criteria pollutants.
(b) Averaging, Banking and Trading (ABT)
    The Phase 1 ABT provisions were patterned on established EPA ABT 
programs that have proven to work well. In Phase 1, the agencies 
determined this flexibility would provide an opportunity for 
manufacturers to make necessary technological improvements and reduce 
the overall cost of the program without compromising overall 
environmental and fuel economy objectives. We propose to generally 
continue this Phase 1 approach with few revisions for vehicles 
regulated in Phase 1. As described in Section IV, we are proposing a 
more limited averaging program for trailers. The agencies see the ABT 
program as playing an important role in making the proposed technology-
advancing standards feasible, by helping to address many issues of 
technological challenges in the context of lead time and costs. It 
provides manufacturers flexibilities that assist the efficient 
development and implementation of new technologies and therefore enable 
new technologies to be implemented at a more aggressive pace than 
without ABT.
    ABT programs are more than just add-on provisions included to help 
reduce costs, and can be, as in EPA's Title II programs generally, an 
integral part of the standard setting itself. A well-designed ABT 
program can also provide important environmental and energy security 
benefits by increasing the speed at which new technologies can be 
implemented (which means that more benefits accrue over time than with 
later-commencing standards) and at the same time increase flexibility 
for, and reduce costs to, the regulated industry and ultimately 
consumers. Without ABT provisions (and other related flexibilities), 
standards would typically have to be numerically less stringent since 
the numerical standard would have to be adjusted to accommodate issues 
of feasibility and available lead time. See 75 FR 25412-25413. By 
offering ABT credits and additional flexibilities the agencies can 
offer progressively more stringent standards that help meet our fuel 
consumption reduction and GHG emission goals at a faster and more cost-
effective pace.\55\
---------------------------------------------------------------------------

    \55\ See NRDC v. Thomas, 805 F. 2d 410, 425 (D.C. Cir. 1986) 
(upholding averaging as a reasonable and permissible means of 
implementing a statutory provision requiring technology-forcing 
standards).
---------------------------------------------------------------------------

(i) Carryover of Phase 1 Credits and Credit Life
    The agencies propose to continue the five-year credit life 
provisions from Phase 1, and are not proposing any

[[Page 40157]]

additional restriction on the use of banked Phase 1 credits in Phase 2. 
In other words, Phase 1 credits in MY2019 could be used in Phase 1 or 
in Phase 2 in MYs 2021-2024. Although, as we have already noted, the 
numerical values of proposed Phase 2 standards are not directly 
comparable in an absolute sense to the existing Phase 1 standards (in 
other words, a given vehicle would have a different g/ton-mile emission 
rate when evaluated using Phase 1 GEM than it would when evaluated 
using Phase 2 GEM), we believe that the Phase 1 and Phase 2 credits are 
largely equivalent. Because the standards and emission levels are 
included in a relative sense (as a difference), it is not necessary for 
the Phase 1 and Phase 2 standards to be directly equivalent in an 
absolute sense in order for the credits to be equivalent.
    This is best understood by examining the way in which credits are 
calculated. For example, the credit equations in 40 CFR 1037.705 and 49 
CFR 535.7 calculate credits as the product of the difference between 
the standard and the vehicle's emission level (g/ton-mile or gallon/
1,000 ton-mile), the regulatory payload (tons), production volume, and 
regulatory useful life (miles). Phase 2 would not change payloads, 
production volumes, or useful lives for tractors, medium and heavy 
heavy-duty engines, or medium and heavy heavy-duty vocational vehicles. 
However, EPA is proposing to change the regulatory useful lives of HD 
pickups and vans, light heavy-duty vocational vehicles, spark-ignited 
engines, and light heavy-duty compression-ignition engines. Because 
useful life is a factor in determining the value of a credit, the 
agencies are proposing interim adjustment factors to ensure banked 
credits maintain their value in the transition from Phase 1 to Phase 2.
    For Phase 1, EPA aligned the useful life for GHG emissions with the 
useful life already in place for criteria pollutants. After the Phase 1 
rules were finalized, EPA updated the useful life for criteria 
pollutants as part of the Tier 3 rulemaking.\56\ The new useful life 
implemented for Tier 3 is 150,000 miles or 15 years, whichever occurs 
first. This is the same useful life proposed in Phase 2 for HD pickups 
and vans, light heavy-duty vocational vehicles, spark-ignited engines, 
and light heavy-duty compression-ignition engines.\57\ The numerical 
value of the adjustment factor for each of these regulatory categories 
depends on the Phase 1 useful life. These are described in detail below 
in this preamble in Sections II, V, and VI. Without these adjustment 
factors the proposed changes in useful life would effectively result in 
a discount of banked credits that are carried forward from Phase 1 to 
Phase 2, which is not the intent of the changes in the useful life. 
With the relatively flat deterioration generally associated with 
CO2, EPA does not believe the proposed changes in useful 
life would significantly affect the feasibility of the proposed Phase 2 
standards. EPA requests comments on the proposed changes to useful 
life. We note that the primary purpose of allowing manufacturers to 
bank credits is to provide flexibility in managing transitions to new 
standards. The five-year credit life is substantial, and would allow 
credits generated in either Phase 1 or early in Phase 2 to be used for 
the intended purpose. The agencies believe longer credit life is not 
necessary to accomplish this transition. Restrictions on credit life 
serve to reduce the likelihood that any manufacturer would be able to 
use banked credits to disrupt the heavy-duty vehicle market in any 
given year by effectively limiting the amount of credits that can be 
held. Without this limit, one manufacturer that saved enough credits 
over many years could achieve a significant cost advantage by using all 
the credits in a single year. The agencies believe, subject to 
consideration of public comment, that allowing a five year credit life 
for all credits, and as a consequence allowing use of Phase 1 credits 
in Phase 2, creates appropriate flexibility and appropriately 
facilitates a smooth transition to each new level of standards.
---------------------------------------------------------------------------

    \56\ 79 FR 23492, April 28, 2014 and 40 CFR 86.1805-17.
    \57\ NHTSA's useful life is based on mileage and years of 
duration.
---------------------------------------------------------------------------

    Although we are not proposing any additional restrictions on the 
use of Phase 1 credits, we are requesting comment on this issue. Early 
indications suggest that positive market reception to the Phase 1 
technologies could lead to manufacturers accumulating credit surpluses 
that could be quite large at the beginning of the proposed Phase 2 
program. This appears especially likely for tractors. The agencies are 
specifically requesting comment on the likelihood of this happening, 
and whether any regulatory changes would be appropriate in response. 
For example, should the agencies limit the amount of credits that could 
be carried over from Phase1 or limit them to the first year or two of 
the Phase 2 program? Also, if we determine that large surpluses are 
likely, how should that factor into our decision on the feasibility of 
more stringent standards in MY 2021?
(ii) Averaging Sets
    EPA has historically restricted averaging to some extent for its HD 
emission standards to avoid creating unfair competitive advantages or 
environmental risks due to credits being inconsistent. Under Phase 1, 
averaging, banking and trading can only occur within and between 
specified ``averaging sets'' (with the exception of credits generated 
through use of specified advanced technologies). We propose to continue 
this regime in Phase 2, to retain the existing vehicle and engine 
averaging sets, and create new trailer averaging sets. We also propose 
to continue the averaging set restrictions from Phase 1 in Phase 2. 
These averaging sets for vehicles are:

 Complete pickups and vans
 Other light heavy-duty vehicles (Classes 2b-5)
 Medium heavy-duty vehicles (Class 6-7)
 Heavy heavy-duty vehicles (Class 8)
 Long dry van trailers
 Short dry van trailers
 Long refrigerated trailers
 Short refrigerated trailers

    We also propose not to allow trading between engines and chassis, 
even within the same vehicle class. Such trading would essentially 
result in double counting of emission credits, because the same engine 
technology would likely generate credits relative to both standards. We 
similarly would limit trading among engine categories to trades within 
the designated averaging sets:

 Spark-ignition engines
 Compression-ignition light heavy-duty engines
 Compression-ignition medium heavy-duty engines
 Compression-ignition heavy heavy-duty engines

    The agencies continue to believe that restricting trading to within 
the same eight classes would provide adequate opportunities for 
manufacturers to make necessary technological improvements and to 
reduce the overall cost of the program without compromising overall 
environmental and fuel efficiency objectives, and is therefore 
appropriate and reasonable under EPA's authority and maximum feasible 
under NHTSA's authority, respectively. We do not expect emissions from 
engines and vehicles--when restricted by weight class--to be 
dissimilar. We therefore expect that the lifetime vehicle performance 
and emissions levels will be very similar across these defined

[[Page 40158]]

categories, and the estimated credit calculations will fairly ensure 
the expected fuel consumption and GHG emission reductions.
    We continue to believe, subject to consideration of public comment, 
that the Phase 1 averaging sets create the most flexibility that is 
appropriate without creating an unfair advantage for manufacturers with 
erratically integrated portfolios, including engines and vehicles. See 
76 FR 57240. The agencies committed in Phase 1 to seek public comment 
after credit trading begins with manufacturers certifying in 2014 on 
whether broader credit trading is more appropriate in developing the 
next phase of HD regulations (76 FR 57128, September 15, 2011). The 
2014 model year end of year reports will become available to the 
agencies in mid-2015. Therefore, the agencies will provide information 
at that point. We welcome comment on averaging set restrictions. The 
agencies propose to continue this carry forward provision for phase 2 
for the same reasons.
(iii) Credit Deficits
    The Phase 1 regulations allow manufacturers to carry-forward 
deficits for up to three years without penalty. This is an important 
flexibility because the program is designed to address the diversity of 
the heavy-duty industry by allowing manufacturers to sell a mix of 
engines or vehicles that have very different emission levels and fuel 
efficiencies. Under this construct, manufacturers can offset sales of 
engines or vehicles not meeting the standards by selling others (within 
the same averaging set) that are much better than required. However, in 
any given year it is possible that the actual sales mix will not 
balance out and the manufacturer may be short of credits for that model 
year. The three year provision allows for this possibility and creates 
additional compliance flexibility to accommodate it.
(iv) Advanced Technology Credits
    At this time, the agencies believe it is no longer appropriate to 
provide extra credit for the technologies identified as advanced 
technologies for Phase 1, although we are requesting comment on this 
issue. The Phase 1 advanced technology credits were adopted to promote 
the implementation of advanced technologies, such as hybrid 
powertrains, Rankine cycle engines, all-electric vehicles, and fuel 
cell vehicles (see 40 CFR 1037.150(i)). As the agencies stated in the 
Phase 1 final rule, the Phase 1 standards were not premised on the use 
of advanced technologies but we expected these advanced technologies to 
be an important part of the Phase 2 rulemaking (76 FR 57133, September 
15, 2011). The proposed Phase 2 heavy-duty engine and vehicles 
standards are premised on the use of some advanced technologies, making 
them equivalent to other fuel-saving technologies in this context. We 
believe the Phase 2 standards themselves would provide sufficient 
incentive to develop them.
    We request comment on this issue, especially with respect to 
electric vehicle, plug-in hybrid, and fuel cell technologies. Although 
the proposed standards are premised on some use of Rankine cycle 
engines and hybrid powertrains, none of the proposed standards are 
based on projected utilization of the use of the other advanced 
technologies. (Note that the most stringent alternative is based on 
some use of these technologies). Commenters are encouraged to consider 
the recently adopted light-duty program, which includes temporary 
incentives for these technologies.
(c) Innovative Technology and Off-Cycle Credits
    The agencies propose to largely continue the Phase 1 innovative 
technology program but to redesignate it as an off-cycle program for 
Phase 2. In other words, beginning in MY 2021 technologies that are not 
fully accounted for in the GEM simulation tool, or by compliance 
dynamometer testing would be considered ``off-cycle'', including those 
technologies that may no longer be considered innovative technologies. 
However, we are not proposing to apply this flexibility to trailers 
(which were not part of Phase 1) in order to simplify the program for 
trailer manufacturers.
    The agencies propose to maintain that, in order for a manufacturer 
to receive credits for Phase 2, the off-cycle technology would still 
need to meet the requirement that it was not in common use prior to MY 
2010. Although, we have not identified specific off-cycle technologies 
at this time that should be excluded, we believe it may be prudent to 
continue this requirement to avoid the potential for manufacturers to 
receive windfall credits for technologies that they were already using 
before MY 2010. Nevertheless, the agencies seek comment on whether off-
cycle technologies in the Phase 2 program should be limited in this 
way. In particular, the agencies are concerned that because the 
proposed Phase 2 program would be implemented MY 2021 and may extend 
beyond 2027, the agencies and manufacturers may have difficulty in the 
future determining whether an off-cycle technology was in common use 
prior to MY 2010. Moreover, because we have not identified a single 
off-cycle technology that should be excluded by this provision at this 
time, we are concerned that this approach may create an unnecessary 
hindrance to the off-cycle program.
    Manufacturers would be able to carry over an innovative technology 
credits from Phase 1 into Phase 2, subject to the same restrictions as 
other credits. Manufacturers would also be able to carry over the 
improvement factor (not the credit value) of a technology, if certain 
criteria were met. The agencies would require documentation for all 
off-cycle requests similar to those required by EPA for its light-duty 
GHG program.
    Additionally, NHTSA would not grant any off-cycle credits for crash 
avoidance technologies. NHTSA would also require manufacturers to 
consider the safety of off-cycle technologies and would request a 
safety assessment from the manufacturer for all off-cycle technologies.
    The agencies seek comment on these proposed changes, as well as the 
possibility of adopting aspects of the light-duty off-cycle program.
(d) Alternative Fuels
    The agencies are proposing to largely continue the Phase 1 approach 
for engines and vehicles fueled by fuels other than gasoline and 
diesel.\58\ Phase 1 engine emission standards applied uniquely for 
gasoline-fueled and diesel-fueled engines. The regulations in 40 CFR 
part 86 implement these distinctions for alternative fuels by dividing 
engines into Otto-cycle and Diesel-cycle technologies based on the 
combustion cycle of the engine. The agencies are, however, proposing a 
small change that is described in Section II. Under the proposed 
change, we would require manufacturers to divide their natural gas 
engines into primary intended service classes, like the current 
requirement for compression-ignition engines. Any alternative fuel-
engine qualifying as a medium heavy-duty engine or a heavy heavy-duty 
engine would be subject to all the emission standards and other 
requirements that apply to compression-ignition engines. Note that this 
small change in approach would also apply with respect to EPA's 
criteria pollutant program.
---------------------------------------------------------------------------

    \58\ See Section I. F. (1) (a) for a summary of certain specific 
changes we are proposing or considering for natural gas-fueled 
engines and vehicles.
---------------------------------------------------------------------------

    We are also proposing that the Phase 2 standards apply exclusively 
at the

[[Page 40159]]

vehicle tailpipe. That is, compliance is based on vehicle fuel 
consumption and GHG emission reductions, and does not reflect any so-
called lifecycle emission properties. The agencies have explained why 
it is reasonable that the heavy duty standards be fuel neutral in this 
manner. See 76 FR 57123; see also 77 FR 51705 (August 24, 2012) and 77 
FR 51500 (August 27, 2012). In particular, EPA notes that there is a 
separate, statutorily-mandated program under the Clean Air Act which 
encourages use of renewable fuels in transportation fuels, including 
renewable fuel used in heavy-duty diesel engines. This program 
considers lifecycle greenhouse gas emissions compared to petroleum 
fuel. NHTSA notes that the fuel efficiency standards are necessarily 
tailpipe-based, and that a lifecycle approach would likely render it 
impossible to harmonize the fuel efficiency and GHG emission standards, 
to the great detriment of our goal of achieving a coordinated program. 
77 FR 51500-51501; see also 77 FR 51705 (similar finding by EPA); see 
also section I.F. (1) (a) below.
    One consequence of the tailpipe-based approach is that the agencies 
are proposing to treat vehicles powered by electricity the same as in 
Phase 1. In Phase 1, EPA treated all electric vehicles as having zero 
emissions of CO2, CH4, and N2O (see 40 
CFR 1037.150(f)). Similarly, NHTSA adopted regulations in Phase 1 that 
set the fuel consumption standards based on the fuel consumed by the 
vehicle. The agencies also did not require emission testing for 
electric vehicles in Phase 1. The agencies considered the potential 
unintended consequence of not accounting for upstream emissions from 
the charging of heavy-duty electric vehicles. In our reassessment for 
Phase 2, we have not found any all-electric heavy-duty vehicles that 
have certified by 2014. As we look to the future, we project very 
limited adoption of all-electric vehicles into the market. Therefore, 
we believe that this provision is still appropriate. Unlike the 2017-
2025 light-duty rule, which included a cap whereby upstream emissions 
would be counted after a certain volume of sales (see 77 FR 62816-
62822), we believe there is no need to propose a cap for heavy-duty 
vehicles because of the small likelihood of significant production of 
EV technologies in the Phase 2 timeframe. We welcome comments on this 
approach.\59\ Note that we also request comment on upstream emissions 
for natural gas in Section XI.
---------------------------------------------------------------------------

    \59\ See also Section I. C. (1) (b)(iv) above (soliciting 
comment on need for advanced technology incentive credits for heavy 
duty EVs).
---------------------------------------------------------------------------

(e) Phase 1 Interim Provisions
    EPA adopted several flexibilities for the Phase 1 program (40 CFR 
1036.150 and 1037.150) as interim provisions. Because the existing 
regulations do not have an end date for Phase 1, most of these 
provisions did not have an explicit end date. NHTSA adopted similar 
provisions. With few exceptions, the agencies are proposing not to 
apply these provisions to Phase 2. These will generally remain in 
effect for the Phase 1 program. In particular, the agencies note that 
we do not propose to continue the blanket exemption for small 
manufacturers. Instead, the agencies propose to adopt narrower and more 
targeted relief.
(f) In-Use Standards
    Section 202(a)(1) of the CAA specifies that EPA is to adopt 
emissions standards that are applicable for the useful life of the 
vehicle and for the engine. EPA finalized in-use standards for the 
Phase 1 program whereas NHTSA adopted an approach which does not 
include these standards. For the Phase 2 program, EPA will carry-over 
its in-use provisions and NHTSA proposes to adopt EPA's useful life 
requirements for its vehicle and engine fuel consumption standards to 
ensure manufacturers consider in the design process the need for fuel 
efficiency standards to apply for the same duration and mileage as EPA 
standards. If EPA determines a manufacturer fails to meet its in-use 
standards, civil penalties may be assessed. NHTSA seeks comment on the 
appropriateness of seeking civil penalties for failure to comply with 
its fuel efficiency standards in these instances. NHTSA would limit 
such penalties to situations in which it determined that the vehicle or 
engine manufacturer failed to comply with the standards.
(2) Proposed Phase 2 Standards
    This section briefly summarizes the proposed Phase 2 standards for 
each category and identifies the technologies that the agencies project 
would be needed to meet the standards. Given the large number of 
different regulatory categories and model years for which separate 
standards are being proposed, the actual numerical standards are not 
listed. Readers are referred to Sections II through IV for the tables 
of proposed standards.
(a) Summary of the Proposed Engine Standards
    The agencies are proposing to continue the basic Phase 1 structure 
for the Phase 2 engine standards. There would be separate standards and 
test cycles for tractor engines, vocational diesel engines, and 
vocational gasoline engines. However, as described in Section II, we 
are proposing a revised test cycle for tractor engines to better 
reflect actual in-use operation.
    For diesel engines, the agencies are proposing standards for MY 
2027 requiring reduction in CO2 emissions and fuel 
consumption of 4.2 percent better than the 2017 baseline.\60\ We are 
also proposing standards for MY 2021 and MY 2024, requiring reductions 
in CO2 emissions and fuel consumption of 1.5 to 3.7 percent 
better than the 2017 baseline. The agencies project that these 
reductions would be feasible based on technological changes that would 
improve combustion and reduce energy losses. For most of these 
improvements, the agencies project manufacturers will begin applying 
them to about 50 percent of their heavy-duty engines by 2021, and 
ultimately apply them to about 90 percent of their heavy-duty engines 
by 2024. However, for some of these improvements we project more 
limited application rates. In particular, we project a more limited use 
of waste exhaust heat recovery systems in 2027, projecting that about 
10 percent of tractor engines will have turbo-compounding systems, and 
an additional 15 percent of tractor engines would employ Rankine-cycle 
waste heat recovery. We do not project that turbo-compounding or 
Rankine-cycle waste heat recovery technology will be utilized in 
vocational engines. Although we see great potential for waste heat 
recovery systems to achieve significant fuel savings and CO2 
emission reductions, we are not projecting that the technology could be 
available for more wide-spread use in this time frame.
---------------------------------------------------------------------------

    \60\ Phase 1 standards for diesel engines will be fully phased-
in by MY 2017.
---------------------------------------------------------------------------

    For gasoline vocational engines, we are not proposing new more 
stringent engine standards. Gasoline engines used in vocational 
vehicles are generally the same engines as are used in the complete HD 
pickups and vans in the Class 2b and 3 weight categories. Given the 
relatively small sales volumes for gasoline-fueled vocational vehicles, 
manufacturers typically cannot afford to invest significantly in 
developing separate technology for these vocational vehicle engines. 
Thus, we project that vocational gasoline engines would

[[Page 40160]]

include the same technology as would be used to meet the pickup and van 
chassis standards, and this would result in some real world reductions 
in CO2 emissions and fuel consumption. Although it is 
difficult at this time to project how much improvement would be 
observed during certification testing, it seems likely that these 
improvements would reduce measured CO2 emissions and fuel 
consumption by about one percent. Therefore, we are requesting comment 
on finalizing a Phase 2 standard of 621 g/hp-hr for gasoline engines 
(i.e., one percent more stringent than the 2016 Phase 1 standard of 627 
g/hp-hr) in MY 2027. We note that the proposed MY 2027 vehicle 
standards for gasoline-fueled vocational vehicles are predicated in 
part on the use of advanced friction reduction technology with 
effectiveness over the GEM cycles of about one percent. We also request 
comment on whether not proposing more stringent standards for gasoline 
engines would create an incentive for purchasers who would have 
otherwise chosen a diesel vehicle to instead choose a gasoline vehicle.

     Table I-2--Summary of Phase 1 and Proposed Phase 2 Requirements for Engines in Combination Tractors and
                                               Vocational Vehicles
----------------------------------------------------------------------------------------------------------------
                                                                 Alternative 3-2027     Alternative 4-2024 (also
                                        Phase 1 program          (proposed standard)      under consideration)
----------------------------------------------------------------------------------------------------------------
Covered in this category.........  Engines installed in tractors and vocational chassis.
----------------------------------------------------------------------------------------------------------------
Share of HDV fuel consumption and  Combination tractors and vocational vehicles account for approximately 85
 GHG emissions.                     percent of fuel use and GHG emissions in the medium and heavy duty truck
                                    sector.
----------------------------------------------------------------------------------------------------------------
Per vehicle fuel consumption and   5%-9% improvement over MY    4% improvement over MY 2017 for diesel engines.
 CO2 improvement.                   2010 baseline, depending    Note that improvements are captured in complete
                                    vehicle application.       vehicle tractor and vocational vehicle standards,
                                    Improvements are in           so that engine improvements and the vehicle
                                    addition to improvements       improvement shown below are not additive.
                                    from tractor and
                                    vocational vehicle
                                    standards.
----------------------------------------------------------------------------------------------------------------
Form of the standard.............  EPA: CO2 grams/horsepower-hour and NHTSA: Gallons of fuel/horsepower-hour.
----------------------------------------------------------------------------------------------------------------
Example technology options         Combustion, air handling,   Further technology improvements and increased use
 available to help manufacturers    friction and emissions        of all Phase 1 technologies, plus waste heat
 meet standards.                    after-treatment            recovery systems for tractor engines (e.g., turbo-
                                    technology improvements.              compound and Rankine-cycle).
----------------------------------------------------------------------------------------------------------------
Flexibilities....................  ABT program which allows   Same as Phase 1, except no advanced technology
                                    emissions and fuel         incentives.
                                    consumption credits to    Adjustment factor of 1.36 proposed for credits
                                    be averaged, banked, or    carried forward from Phase 1 to Phase 2 for SI
                                    traded (five year credit   and LHD CI engines due to proposed change in
                                    life). Manufacturers       useful life.
                                    allowed to carry-forward
                                    credit deficits for up
                                    to three model years.
                                    Interim incentives for
                                    advanced technologies,
                                    recognition of
                                    innovative (off-cycle)
                                    technologies not
                                    accounted for by the HD
                                    Phase 1 test procedures,
                                    and credits for
                                    certifying early.
----------------------------------------------------------------------------------------------------------------

(b) Summary of the Proposed Tractor Standards
    As explained in Section III, the agencies are proposing to largely 
continue the Phase 1 tractor program but to propose new standards. The 
tractor standards proposed for MY 2027 would achieve up to 24 percent 
lower CO2 emissions and fuel consumption than a 2017 model 
year Phase 1 tractor. The agencies project that the proposed 2027 
tractor standards could be met through improvements in the:
     Engine \61\ (including some use of waste heat recovery 
systems)
---------------------------------------------------------------------------

    \61\ Although the agencies are proposing separate engine 
standards and separate engine certification, engine improvements 
would also be reflected in the vehicle certification process. Thus, 
it is appropriate to also consider engine improvements in the 
context of the vehicle standards.
---------------------------------------------------------------------------

     Transmission
     Driveline
     Aerodynamic design
     Tire rolling resistance
     Idle performance
     Other accessories of the tractor.
    The agencies' evaluation shows that some of these technologies are 
available today, but have very low adoption rates on current vehicles, 
while others will require some lead time for development. The agencies 
are proposing to enhance the GEM vehicle simulation tool to recognize 
these technologies, as described in Section II.C.
    We have also determined that there is sufficient lead time to 
introduce many of these tractor and engine technologies into the fleet 
at a reasonable cost starting in the 2021 model year. The proposed 2021 
model year standards for combination tractors and engines would achieve 
up to 13 percent lower CO2 emissions and fuel consumption 
than a 2017 model year Phase 1 tractor, and the 2024 model year 
standards would achieve up to 20 percent lower CO2 emissions 
and fuel consumption.

[[Page 40161]]



  Table I-3--Summary of Phase 1 and Proposed Phase 2 Requirements for Class 7 and Class 8 Combination Tractors
----------------------------------------------------------------------------------------------------------------
                                                                                           Alternative 4--2024
                                        Phase 1 program          Alternative 3--2027           (also under
                                                                 (proposed standard)         consideration)
----------------------------------------------------------------------------------------------------------------
Covered in this category.........          Tractors that are designed to pull trailers and move freight.
----------------------------------------------------------------------------------------------------------------
Share of HDV fuel consumption and   Combination tractors and their engines account for approximately two thirds
 GHG emissions.                       of fuel use and GHG emissions in the medium and heavy duty truck sector.
----------------------------------------------------------------------------------------------------------------
Per vehicle fuel consumption and   10%-23% improvement over       18%-24% improvement over MY 2017 standards.
 CO2 improvement.                   MY 2010 baseline,
                                    depending on tractor
                                    category. Improvements
                                    are in addition to
                                    improvements from engine
                                    standards.
----------------------------------------------------------------------------------------------------------------
Form of the standard.............   EPA: CO2 grams/ton payload mile and NHTSA: Gallons of fuel/1,000 ton payload
                                                                        mile.
----------------------------------------------------------------------------------------------------------------
Example technology options         Aerodynamic drag            Further technology improvements and increased use
 available to help manufacturers    improvements; low               of all Phase 1 technologies, plus engine
 meet standards.                    rolling resistance                improvements, improved and automated
                                    tires; high strength       transmissions and axles, powertrain optimization,
                                    steel and aluminum           tire inflation systems, and predictive cruise
                                    weight reduction;                 control (depending on tractor type).
                                    extended idle reduction;
                                    and speed limiters.
----------------------------------------------------------------------------------------------------------------
Flexibilities....................  ABT program which allows      Same as Phase 1, except no extra credits for
                                    emissions and fuel           advanced technologies or early certification.
                                    consumption credits to
                                    be averaged, banked, or
                                    traded (five year credit
                                    life). Manufacturers
                                    allowed to carry-forward
                                    credit deficits for up
                                    to three model years.
                                    Interim incentives for
                                    advanced technologies,
                                    recognition of
                                    innovative (off-cycle)
                                    technologies not
                                    accounted for by the HD
                                    Phase 1 test procedures,
                                    and credits for
                                    certifying early.
----------------------------------------------------------------------------------------------------------------

(c) Summary of the Proposed Trailer Standards
    This proposed rule is a set of GHG emission and fuel consumption 
standards for manufacturers of new trailers that are used in 
combination with tractors that would significantly reduce 
CO2 and fuel consumption from combination tractor-trailers 
nationwide over a period of several years. As described in Section IV, 
there are numerous aerodynamic and tire technologies available to 
manufacturers to accomplish these proposed standards. For the most 
part, these technologies have already been introduced into the market 
to some extent through EPA's voluntary SmartWay program. However, 
adoption is still somewhat limited.
    The agencies are proposing incremental levels of Phase 2 standards 
that would apply beginning in MY 2018 and be fully phased-in by 2027. 
These standards are predicated on use of aerodynamic and tire 
improvements, with trailer OEMs making incrementally greater 
improvements in MYs 2021 and 2024 as standard stringency increases in 
each of those model years. EPA's GHG emission standards would be 
mandatory beginning in MY 2018, while NHTSA's fuel consumption 
standards would be voluntary beginning in MY 2018, and be mandatory 
beginning in MY 2021.
    As described in Section XV.D and Chapter 12 of the draft RIA, the 
agencies are proposing special provisions to minimize the impacts on 
small trailer manufacturers. These provisions have been informed by and 
are largely consistent with recommendations coming from the SBAR Panel 
that EPA conducted pursuant to Section 609(b) of the Regulatory 
Flexibility Act (RFA). Broadly, these provisions provide additional 
lead time for small manufacturers, as well as simplified testing and 
compliance requirements. The agencies are also requesting comment on 
whether there is a need for additional provisions to address small 
business issues.

                        Table I-4--Summary of Proposed Phase 2 Requirements for Trailers
----------------------------------------------------------------------------------------------------------------
                                                                                           Alternative 4--2024
                                        Phase 1 program          Alternative 3--2027           (also under
                                                                 (proposed standard)         consideration)
----------------------------------------------------------------------------------------------------------------
Covered in this category.........     Trailers hauled by low, mid, and high roof day and sleeper cab tractors,
                                        except those qualified as logging, mining, stationary or heavy-haul.
----------------------------------------------------------------------------------------------------------------
Share of HDV fuel consumption and    Trailers are modeled together with combination tractors and their engines.
 GHG emissions.                        Together, they account for approximately two thirds of fuel use and GHG
                                                emissions in the medium and heavy duty truck sector.
----------------------------------------------------------------------------------------------------------------
Per vehicle fuel consumption and   N/A......................      Between 3% and 8% improvement over MY 2017
 CO2 improvement.                                                   baseline, depending on the trailer type.
----------------------------------------------------------------------------------------------------------------

[[Page 40162]]

 
Form of the standard.............  N/A......................  EPA: CO2 grams/ton payload mile and NHTSA: Gallons/
                                                                            1,000 ton payload mile.
----------------------------------------------------------------------------------------------------------------
Example technology options         N/A......................     Low rolling resistance tires, automatic tire
 available to help manufacturers                                  inflation systems, weight reduction for most
 meet standards.                                                trailers, aerodynamic improvements such as side
                                                                  and rear fairings, gap closing devices, and
                                                                 undercarriage treatment for box-type trailers
                                                                       (e.g., dry and refrigerated vans).
----------------------------------------------------------------------------------------------------------------
Flexibilities....................  N/A......................      One year delay in implementation for small
                                                                 businesses, trailer manufacturers may use pre-
                                                                  approved devices to avoid testing, averaging
                                                               program for manufacturers of dry and refrigerated
                                                                                 box trailers.
----------------------------------------------------------------------------------------------------------------

(d) Summary of the Proposed Vocational Vehicle Standards
    As explained in Section V, the agencies are proposing to revise the 
Phase 1 vocational vehicle program and to propose new standards. These 
proposed standards also reflect further sub-categorization from Phase 
1, with separate proposed standards based on mode of operation: Urban, 
regional, and multi-purpose. The agencies are also proposing 
alternative standards for emergency vehicles.
    The agencies project that the proposed vocational vehicle standards 
could be met through improvements in the engine, transmission, 
driveline, lower rolling resistance tires, workday idle reduction 
technologies, and weight reduction, plus some application of hybrid 
technology. These are described in Section V of this preamble and in 
Chapter 2.9 of the draft RIA. These MY 2027 standards would achieve up 
to 16 percent lower CO2 emissions and fuel consumption than 
MY 2017 Phase 1 standards. The agencies are also proposing revisions to 
the compliance regime for vocational vehicles. These include: The 
addition of an idle cycle that would be weighted along with the other 
drive cycles; and revisions to the vehicle simulation tool to reflect 
specific improvements to the engine, transmission, and driveline.
    Similar to the tractor program, we have determined that there is 
sufficient lead time to introduce many of these new technologies into 
the fleet starting in MY 2021. Therefore, we are proposing new 
standards for MY 2021 and 2024. Based on our analysis, the MY 2021 
standards for vocational vehicles would achieve up to 7 percent lower 
CO2 emissions and fuel consumption than a MY 2017 Phase 1 
vehicle, on average, and the MY 2024 standards would achieve up to 11 
percent lower CO2 emissions and fuel consumption.
    In Phase 1, EPA adopted air conditioning (A/C) refrigerant leakage 
standards for tractors, as well as for heavy-duty pickups and vans, but 
not for vocational vehicles. For Phase 2, EPA believes that it would be 
feasible to apply similar A/C refrigerant leakage standards for 
vocational vehicles, beginning with the 2021 model year. The process 
for certifying that low leakage components are used would follow the 
system currently in place for comparable systems in tractors.

         Table I-5--Summary of Phase 1 and Proposed Phase 2 Requirements for Vocational Vehicle Chassis
----------------------------------------------------------------------------------------------------------------
                                                                                           Alternative 4--2024
                                        Phase 1 program          Alternative 3--2027           (also under
                                                                 (proposed standard)         consideration)
----------------------------------------------------------------------------------------------------------------
Covered in this category.........  Class 2b-8 chassis that are intended for vocational services such as delivery
                                     vehicles, emergency vehicles, dump truck, tow trucks, cement mixer, refuse
                                            trucks, etc., except those qualified as off-highway vehicles.
----------------------------------------------------------------------------------------------------------------
                                     Because of sector diversity, vocational vehicle chassis are segmented into
                                       Light, Medium and Heavy Duty vehicle categories and for Phase 2 each of
                                      these segments are further subdivided using three duty cycles: Regional,
                                                              Multi-purpose, and Urban.
----------------------------------------------------------------------------------------------------------------
Share of HDV fuel consumption and   Vocational vehicles account for approximately 20 percent of fuel use and GHG
 GHG emissions.                            emissions in the medium and heavy duty truck sector categories.
----------------------------------------------------------------------------------------------------------------
Per vehicle fuel consumption and   2% improvement over MY        Up to 16% improvement over MY 2017 standards.
 CO2 improvement.                   2010 baseline.
                                   Improvements are in
                                    addition to improvements
                                    from engine standards.
----------------------------------------------------------------------------------------------------------------
Form of the standard.............   EPA: CO2 grams/ton payload mile and NHTSA: Gallons of fuel/1,000 ton payload
                                                                        mile.
----------------------------------------------------------------------------------------------------------------
Example technology options         Low rolling resistance      Further technology improvements and increased use
 available to help manufacturers    tires.                      of Phase 1 technologies, plus improved engines,
 meet standards.                                               transmissions and axles, powertrain optimization,
                                                                  weight reduction, hybrids, and workday idle
                                                                               reduction systems.
----------------------------------------------------------------------------------------------------------------

[[Page 40163]]

 
Flexibilities....................  ABT program which allows     Same as Phase 1, except no advanced technology
                                    emissions and fuel                            incentives.
                                    consumption credits to
                                    be averaged, banked, or
                                    traded (five year credit
                                    life). Manufacturers
                                    allowed to carry-forward
                                    credit deficits for up
                                    to three model years.
                                    Interim incentives for
                                    advanced technologies,
                                    recognition of
                                    innovative (off-cycle)
                                    technologies not
                                    accounted for by the HD
                                    Phase 1 test procedures,
                                    and credits for
                                    certifying early.
                                   .........................     Chassis intended for emergency vehicles have
                                                                proposed Phase 2 standards based only on Phase 1
                                                               technologies, and may continue to certify using a
                                                                 simplified Phase 1-style GEM tool. Adjustment
                                                                  factor of 1.36 proposed for credits carried
                                                                forward from Phase 1 to Phase 2 due to proposed
                                                                             change in useful life.
----------------------------------------------------------------------------------------------------------------

(e) Summary of the Proposed Heavy-Duty Pickup and Van Standards
    The agencies are proposing to adopt new Phase 2 GHG emission and 
fuel consumption standards for heavy-duty pickups and vans that would 
be applied in largely the same manner as the Phase 1 standards. These 
standards are based on the extensive use of most known and proven 
technologies, and could result in some use of strong hybrid powertrain 
technology. These proposed standards would commence in MY 2021. 
Overall, the proposed standards are 16 percent more stringent by 2027.

             Table I-6--Summary of Phase 1 and Proposed Phase 2 Requirements for HD Pickups and Vans
----------------------------------------------------------------------------------------------------------------
                                                                                           Alternative 4--2025
                                        Phase 1 program          Alternative 3--2027           (also under
                                                                 (proposed standard)         consideration)
----------------------------------------------------------------------------------------------------------------
Covered in this category.........   Class 2b and 3 complete pickup trucks and vans, including all work vans and
                                    15-passenger vans but excluding 12-passenger vans which are subject to light-
                                                                   duty standards.
----------------------------------------------------------------------------------------------------------------
Share of HDV fuel consumption and      HD pickups and vans account for approximately 15% of fuel use and GHG
 GHG emissions.                                 emissions in the medium and heavy duty truck sector.
----------------------------------------------------------------------------------------------------------------
Per vehicle fuel consumption and   15% improvement over MY       16% improvement over MY 2018-2020 standards.
 CO2 improvement.                   2010 baseline for diesel
                                    vehicles, and 10%
                                    improvement for gasoline
                                    vehicles.
----------------------------------------------------------------------------------------------------------------
Form of the standard.............    Phase 1 standards are based upon a ``work factor'' attribute that combines
                                     truck payload and towing capabilities, with an added adjustment for 4-wheel
                                       drive vehicles. There are separate target curves for diesel-powered and
                                    gasoline-powered vehicles. As proposed, the Phase 2 standards would be based
                                                                on the same approach.
----------------------------------------------------------------------------------------------------------------
Example technology options         Engine improvements,        Further technology improvements and increased use
 available to help manufacturers    transmission                 of all Phase 1 technologies, plus engine stop-
 meet standards.                    improvements,                start, and powertrain hybridization (mild and
                                    aerodynamic drag                                strong).
                                    improvements, low
                                    rolling resistance
                                    tires, weight reduction,
                                    and improved accessories.
----------------------------------------------------------------------------------------------------------------

[[Page 40164]]

 
Flexibilities....................  Two optional phase-in         Proposed to be same as Phase 1, with phase-in
                                    schedules; ABT program        schedule based on year-over-year increase in
                                    which allows emissions       stringency. Adjustment factor of 1.25 proposed
                                    and fuel consumption       for credits carried forward from Phase 1 to Phase
                                    credits to be averaged,    2 due to proposed change in useful life. Proposed
                                    banked, or traded (five      cessation of advanced technology incentives in
                                    year credit life).            2021 and continuation of off-cycle credits.
                                    Manufacturers allowed to
                                    carry-forward credit
                                    deficits for up to three
                                    model years. Interim
                                    incentives for advanced
                                    technologies,
                                    recognition of
                                    innovative (off-cycle)
                                    technologies not
                                    accounted for by the HD
                                    Phase 1 test procedures,
                                    and credits for
                                    certifying early.
----------------------------------------------------------------------------------------------------------------

(f) Summary of the Proposed Final Numeric Standards by Regulatory 
Subcategory
    Table I-7 lists the proposed final (i.e., MY 2027) numeric 
standards by regulatory subcategory for tractors, trailers, vocational 
vehicles and engines. Note that these are the same final numeric 
standards for Alternative 4, but for Alternative 4 these would be 
implemented in MY 2024 instead of MY 2027.

                 Table I-7--Proposed Final (MY 2027) Numeric Standards by Regulatory Subcategory
----------------------------------------------------------------------------------------------------------------
                                                                CO2 grams per  ton-mile  Fuel consumption gallon
                                                                 (for engines CO2 grams  per 1,000 ton-mile (for
                    Regulatory subcategory                       per brake horsepower-   engines gallons per 100
                                                                         hour)            brake horsepower-hour)
----------------------------------------------------------------------------------------------------------------
Tractors:.....................................................
    Class 7 Low Roof Day Cab..................................                       87                   8.5462
    Class 7 Mid Roof Day Cab..................................                       96                   9.4303
    Class 7 High Roof Day Cab.................................                       96                   9.4303
    Class 8 Low Roof Day Cab..................................                       70                   6.8762
    Class 8 Mid Roof Day Cab..................................                       76                   7.4656
    Class 8 High Roof Day Cab.................................                       76                   7.4656
    Class 8 Low Roof Sleeper Cab..............................                       62                   6.0904
    Class 8 Mid Roof Sleeper Cab..............................                       69                   6.7780
    Class 8 High Roof Sleeper Cab.............................                       67                   6.5815
Trailers:
    Long Dry Box Trailer......................................                       77                   7.5639
    Short Dry Box Trailer.....................................                      140                  13.7525
    Long Refrigerated Box Trailer.............................                       80                   7.8585
    Short Refrigerated Box Trailer............................                      144                  14.1454
Vocational Diesel:
    LHD Urban.................................................                      272                  26.7191
    LHD Multi-Purpose.........................................                      280                  27.5049
    LHD Regional..............................................                      292                  28.6837
    MHD Urban.................................................                      172                  16.8959
    MHD Multi-Purpose.........................................                      174                  17.0923
    MHD Regional..............................................                      170                  16.6994
    HHD Urban.................................................                      182                  17.8782
    HHD Multi-Purpose.........................................                      183                  17.9764
    HHD Regional..............................................                      174                  17.0923
Vocational Gasoline:
    LHD Urban.................................................                      299                  33.6446
    LHD Multi-Purpose.........................................                      308                  34.6574
    LHD Regional..............................................                      321                  36.1202
    MHD Urban.................................................                      189                  21.2670
    MHD Multi-Purpose.........................................                      191                  21.4921
    MHD Regional..............................................                      187                  21.0420
    HHD Urban.................................................                      196                  22.0547
    HHD Multi-Purpose.........................................                      198                  22.2797
    HHD Regional..............................................                      188                  21.1545
Diesel Engines:
    LHD Vocational............................................                      553                   5.4322
    MHD Vocational............................................                      553                   5.4322
    HHD Vocational............................................                      533                   5.2358
    MHD Tractor...............................................                      466                   4.5776

[[Page 40165]]

 
    HHD Tractor...............................................                      441                   4.3320
----------------------------------------------------------------------------------------------------------------

    Similar to Phase 1 the agencies are proposing for Phase 2 a set of 
continuous equation-based standards for HD pickups and vans. Please 
refer to Section 6, subsection B.1, for a description of these 
standards, including associated tables and figures.

D. Summary of the Costs and Benefits of the Proposed Rule

    This section summarizes the projected costs and benefits of the 
proposed NHTSA fuel consumption and EPA GHG emission standards, along 
with those of Alternative 4. These projections helped to inform the 
agencies' choices among the alternatives considered, along with other 
relevant factors, and NHTSA's Draft Environmental Impact Statement 
(DEIS). See Sections VII through IX and the Draft RIA for additional 
details about these projections.
    For this rule, the agencies conducted coordinated and complementary 
analyses using two analytical methods for the heavy-duty pickup and van 
segment by employing both DOT's CAFE model and EPA's MOVES model. The 
agencies used EPA's MOVES model to estimate fuel consumption and 
emissions impacts for tractor-trailers (including the engine that 
powers the tractor), and vocational vehicles (including the engine that 
powers the vehicle). Additional calculations were performed to 
determine corresponding monetized program costs and benefits. For 
heavy-duty pickups and vans, the agencies performed complementary 
analyses, which we refer to as ``Method A'' and ``Method B.'' In Method 
A, the CAFE model was used to project a pathway the industry could use 
to comply with each regulatory alternative and the estimated effects on 
fuel consumption, emissions, benefits and costs. In Method B, the CAFE 
model was used to project a pathway the industry could use to comply 
with each regulatory alternative, along with resultant impacts on per 
vehicle costs, and the MOVES model was used to calculate corresponding 
changes in total fuel consumption and annual emissions. Additional 
calculations were performed to determine corresponding monetized 
program costs and benefits. NHTSA considered Method A as its central 
analysis and Method B as a supplemental analysis. EPA considered the 
results of both methods. The agencies concluded that both methods led 
the agencies to the same conclusions and the same selection of the 
proposed standards. See Section VII for additional discussion of these 
two methods.
(1) Reference Case Against Which Costs and Benefits Are Calculated
    The No Action Alternative for today's analysis, alternatively 
referred to as the ``baseline'' or ``reference case,'' assumes that the 
agencies would not issue new rules regarding MD/HD fuel efficiency and 
GHG emissions. This is the baseline against which costs and benefits 
for the proposed standards are calculated. The reference case assumes 
that model year 2018 standards would be extended indefinitely and 
without change.
    The agencies recognize that if the proposed rule is not adopted, 
manufacturers will continue to introduce new heavy-duty vehicles in a 
competitive market that responds to a range of factors. Thus 
manufacturers might have continued to improve technologies to reduce 
heavy-duty vehicle fuel consumption. Thus, as described in Section VII, 
both agencies fully analyzed the proposed standards and the regulatory 
alternatives against two reference cases. The first case uses a 
baseline that projects very little improvement in new vehicles in the 
absence of new Phase 2 standards, and the second uses a more dynamic 
baseline that projects more significant improvements in vehicle fuel 
efficiency. NHTSA considered its primary analysis to be based on the 
more dynamic baseline, where certain cost-effective technologies are 
assumed to be applied by manufacturers to improve fuel efficiency 
beyond the Phase 1 requirements in the absence of new Phase 2 
standards. EPA considered both reference cases. The results for all of 
the regulatory alternatives relative to both reference cases, derived 
via the same methodologies discussed in this section, are presented in 
Section X of the preamble.
    The agencies chose to analyze these two different baselines because 
the agencies recognize that there are a number of factors that create 
uncertainty in projecting a baseline against which to compare the 
future effects of the proposed action and the remaining alternatives. 
The composition of the future fleet--such as the relative position of 
individual manufacturers and the mix of products they each offer--
cannot be predicted with certainty at this time. Additionally, the 
heavy-duty vehicle market is diverse, as is the range of vehicle 
purchasers. Heavy-duty vehicle manufacturers have reported that their 
customers' purchasing decisions are influenced by their customers' own 
determinations of minimum total cost of ownership, which can be unique 
to a particular customer's circumstances. For example, some customers 
(e.g., less-than-truckload or package delivery operators) operate their 
vehicles within a limited geographic region and typically own their own 
vehicle maintenance and repair centers within that region. These 
operators tend to own their vehicles for long time periods, and 
sometimes for the entire service life of the vehicle. Their total cost 
of ownership is influenced by their ability to better control their own 
maintenance costs, and thus they can afford to consider fuel efficiency 
technologies that have longer payback periods, outside of the vehicle 
manufacturer's warranty period. Other customers (e.g. truckload or 
long-haul operators) tend to operate cross-country, and thus must 
depend upon truck dealer service centers for repair and maintenance. 
Some of these customers tend to own their vehicles for about four to 
seven years, so that they typically do not have to pay for repair and 
maintenance costs outside of either the manufacturer's warranty period 
or some other extended warranty period. Many of these customers tend to 
require seeing evidence of fuel efficiency technology payback periods 
on the order of 18 to 24 months before seriously considering evaluating 
a new technology for potential adoption within their fleet (NAS 2010, 
Roeth et al. 2013, Klemick et al. 2014). Purchasers of HD pickups and 
vans wanting better fuel efficiency tend to demand that fuel 
consumption improvements pay back within approximately one to three 
years, but some HD pickup and van owners accrue

[[Page 40166]]

relatively few vehicle miles traveled per year, such that they may be 
less likely to adopt new fuel efficiency technologies, while other 
owners who use their vehicle(s) with greater intensity may be even more 
willing to pay for fuel efficiency improvements. Regardless of the type 
of customer, their determination of minimum total cost of ownership 
involves the customer balancing their own unique circumstances with a 
heavy-duty vehicle's initial purchase price, availability of credit and 
lease options, expectations of vehicle reliability, resale value and 
fuel efficiency technology payback periods. The degree of the incentive 
to adopt additional fuel efficiency technologies also depends on 
customer expectations of future fuel prices, which directly impacts 
customer payback periods. Purchasing decisions are not based 
exclusively on payback period, but also include the considerations 
discussed above and in Section X.A.1. For the baseline analysis, the 
agencies use payback period as a proxy for all of these considerations, 
and therefore the payback period for the baseline analysis is shorter 
than the payback period industry uses as a threshold for the further 
consideration of a technology. The agencies request comment on which 
alternative baseline scenarios would be most appropriate for analysis 
in the final rule. Specifically, the agencies request empirical 
evidence to support whether the agencies should use for the final rule 
the central cases used in this proposal, alternative sensitivity cases 
such as those mentioned below, or some other scenarios. See Section 
X.A.1of this Preamble and Chapter 11 of the draft RIA for a more 
detailed discussion of baselines.
    As part of a sensitivity analysis, additional baseline scenarios 
were also evaluated for HD pickups and vans, including baseline payback 
periods of 12, 18 and 24 months. See Section VI of this Preamble and 
Chapter 10 of the draft RIA for a detailed discussion of these 
additional scenarios.
(2) Costs and Benefits Projected for the Standards Being Proposed and 
Alternative 4
    The tables below summarize the benefits and costs for the program 
in two ways: First, from the perspective of a program designed to 
improve the Nation's energy security and to conserve energy by 
improving fuel efficiency and then from the perspective of a program 
designed to reduce GHG emissions. The individual categories of benefits 
and costs presented in the tables below are defined more fully and 
presented in more detail in Chapter 8 of the draft RIA.
    Table I-8 shows benefits and costs for the proposed standards and 
Alternative 4 from the perspective of a program designed to improve the 
Nation's energy security and conserve energy by improving fuel 
efficiency. From this viewpoint, technology costs occur when the 
vehicle is purchased. Fuel savings are counted as benefits that occur 
over the lifetimes of the vehicles produced during the model years 
subject to the Phase 2 standards as they consume less fuel.

  Table I-8--Lifetime Fuel Savings, GHG Reductions, Benefits, Costs and Net Benefits for Model Years 2018-2029
                                        Vehicles Using Analysis Method A
                                           [Billions of 2012$] \a\ \b\
----------------------------------------------------------------------------------------------------------------
                                                                        Alternative
                                         -----------------------------------------------------------------------
                Category                              3 Preferred                              4
                                         -----------------------------------------------------------------------
                                          7% Discount rate  3% Discount rate  7% Discount rate  3% Discount rate
----------------------------------------------------------------------------------------------------------------
Fuel Reductions (Billion Gallons).......               72.2-76.7
                                                       81.9-86.7
GHG reductions (MMT CO2 eq).............               974-1,034
                                                      1,102-1,166
                                         -----------------------------------------------------------------------
Vehicle Program: Technology and Indirect         25.0-25.4         16.8-17.1         32.9-34.3         22.5-23.5
 Costs, Normal Profit on Additional
 Investments............................
Additional Routine Maintenance..........           1.0-1.1           0.6-0.6           1.0-1.1           0.6-0.7
Congestion, Accidents, and Noise from              4.5-4.7           2.6-2.8           4.7-4.9           2.7-2.8
 Increased Vehicle Use..................
                                         -----------------------------------------------------------------------
    Total Costs.........................         30.5-31.1         20.0-20.5         38.7-40.8         25.8-27.0
Fuel Savings (valued at pre-tax prices).       165.1-175.1         89.2-94.2       187.4-198.3       102.0-107.5
Savings from Less Frequent Refueling....           2.9-3.1           1.5-1.6           3.4-3.6           1.8-2.0
Economic Benefits from Additional                14.7-15.1           8.2-8.4         15.0-15.4           8.4-8.6
 Vehicle Use............................
Reduced Climate Damages from GHG                 32.9-34.9         32.9-34.9         37.3-39.4         37.3-39.4
 Emissions \c\..........................
Reduced Health Damages from Non-GHG              37.2-38.8           20-20.7         40.9-42.5         22.1-22.8
 Emissions..............................
Increased U.S. Energy Security..........           8.1-8.9           4.3-4.7          9.3-10.2           5.0-5.5
                                         -----------------------------------------------------------------------
    Total Benefits......................           261-276           156-165           293-309           177-186
                                         -----------------------------------------------------------------------
        Net Benefits....................           231-245           136-144           255-269           151-159
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.
\b\ Range reflects two reference case assumptions 1a and 1b.
\c\ Benefits and net benefits use the 3 percent global average SCC value applied only to CO2 emissions; GHG
  reductions include CO2, CH4, N2O and HFC reductions, and include benefits to other nations as well as the U.S.
  See Draft RIA Chapter 8.5 and Preamble Section IX.G for further discussion.

    Table I-9 shows benefits and cost from the perspective of reducing 
GHG.

[[Page 40167]]



  Table I-9--Lifetime Fuel Savings, GHG Reductions, Benefits, Costs and Net Benefits for Model Years 2018-2029
                                        Vehicles Using Analysis Method B
                                           [Billions of 2012$] \a\ \b\
----------------------------------------------------------------------------------------------------------------
                                                                  Alternative
                              ----------------------------------------------------------------------------------
           Category                           3 Preferred                                   4
                              ----------------------------------------------------------------------------------
                                 7% Discount rate     3% Discount rate     7% Discount rate    3% Discount rate
----------------------------------------------------------------------------------------------------------------
Fuel Reductions (Billion                     70.2 to 75.8
 Gallons).
                                             79.7 to 85.4
GHG reductions (MMT CO2eq)...                960 to 1,040
                                            1,090 to 1,160
                              ----------------------------------------------------------------------------------
Vehicle Program (e.g.,         -$24.6 to -$25.1     -$16.3 to -$16.6     -$33.1 to -$33.5     -$22.2 to -$22.5
 technology and indirect
 costs, normal profit on
 additional investments).
Additional Routine             -$1.1 to -$1.1       -$0.6 to -$0.6       -$1.1 to -$1.1       -$0.6 to -$0.6
 Maintenance.
Fuel Savings (valued at pre-   $159 to $171         $84.2 to $90.1       $181 to $193         $96.5 to $103
 tax prices).
Energy Security..............  $8.5 to $9.3         $4.4 to $4.8         $9.8 to $10.6        $5.2 to $5.6
Congestion, Accidents, and     -$4.2 to -$4.3       -$2.4 to -$2.4       -$4.2 to -$4.3       -$2.4 to -$2.4
 Noise from Increased Vehicle
 Use.
Savings from Less Frequent     $2.8 to $3.1         $1.4 to $1.6         $3.3 to $3.6         $1.7 to $1.9
 Refueling.
Economic Benefits from         $14.8 to $14.9       $8.2 to $8.2         $14.7 to $14.8       $8.1 to $8.1
 Additional Vehicle Use.
Benefits from Reduced Non-GHG  $37.4 to $39.7       $17.7 to $18.8       $41.2 to $43.5       $19.7 to $20.7
 Emissions \c\.
                              ----------------------------------------------------------------------------------
Reduced Climate Damages from                $31.6 to $34.0
 GHG Emissions \d\.
                                            $35.9 to $38.3
                              ----------------------------------------------------------------------------------
    Net Benefits.............  $224 to $242         $128 to $138         $248 to $265         $142 to $152
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.
\b\ Range reflects two baseline assumptions 1a and 1b.
\c\ Range reflects both the two baseline assumptions 1a and 1b using the mid-point of the low and high $/ton
  estimates for calculating benefits.
\d\ Benefits and net benefits use the 3 percent average SCCO2 value applied only to CO2 emissions; GHG
  reductions include CO2, CH4 and N2O reductions.

    Table I-10 breaks down by vehicle category the benefits and costs 
for the proposed standards and Alternative 4 using the Method A 
analytical approach. For additional detail on per-vehicle break-downs 
of costs and benefits, please see Chapter 10.

  Table I-10--Per Vehicle Category Lifetime Fuel Savings, GHG Reductions, Benefits, Costs and Net Benefits for
     Model Years 2018-2029 Vehicles Using Analysis Method A (Billions of 2012$), Relative to Baseline 1b \a\
----------------------------------------------------------------------------------------------------------------
                                                                        Alternative
                                         -----------------------------------------------------------------------
    Key costs and benefits by vehicle                 3 Preferred                              4
                category                 -----------------------------------------------------------------------
                                          7% Discount rate  3% Discount rate  7% Discount rate  3% Discount rate
----------------------------------------------------------------------------------------------------------------
Tractors, Including Engines, and
 Trailers:..............................
    Fuel Reductions (Billion Gallons)...                 56.1
                                                         61.6
    GHG Reductions (MMT CO2 eq).........                 731.1
                                                         803.1
                                         -----------------------------------------------------------------------
        Total Costs.....................              15.2              10.0              17.7              11.9
        Total Benefits..................             177.8             105.4             194.2             115.7
        Net Benefits....................             162.6              95.4             176.5             103.9
Vocational Vehicles, Including Engines:
                                         -----------------------------------------------------------------------
    Fuel Reductions (Billion Gallons)...                  8.3
                                                         10.9
    GHG Reductions (MMT CO2 eq).........                 107.0
                                                         139.8
                                         -----------------------------------------------------------------------
        Total Costs.....................               9.5               6.1              12.8               8.4
        Total Benefits..................              27.7              16.0              35.0              20.6
        Net Benefits....................              18.1               9.9              22.1              12.1
HD Pickups and Vans:
                                         -----------------------------------------------------------------------
    Fuel Reductions (Billion Gallons)...                  7.8
                                                          9.3
    GHG Reductions (MMT CO2 eq).........                 94.1
                                                         112.8
                                         -----------------------------------------------------------------------
        Total Costs.....................               5.5               3.7               7.8               5.3

[[Page 40168]]

 
        Total Benefits..................              23.5              14.1              28.3              17.1
        Net Benefits....................              18.0              10.5              20.4              11.9
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ For an explanation of analytical Methods A and B, please see Section I.D; for an explanation of the less
  dynamic baseline, 1a, and more dynamic baseline, 1b, please see Section X.A.1.


                              Table I-11--Per Vehicle Costs Relative to Baseline 1a
----------------------------------------------------------------------------------------------------------------
                                               3 Proposed standards                              4
                                 -------------------------------------------------------------------------------
                                      MY 2021         MY 2024         MY 2027         MY 2021         MY 2024
----------------------------------------------------------------------------------------------------------------
Per Vehicle Cost ($) \a\
    Tractors....................          $6,710          $9,940         $11,700         $10,200         $12,400
    Trailers....................             900           1,010           1,170           1,080           1,230
    Vocational Vehicles.........           1,150           1,770           3,380           1,990           3,590
    Pickups/Vans................             520             950           1,340           1,050           1,730
----------------------------------------------------------------------------------------------------------------
Note:
\a\ Per vehicle costs include new engine and vehicle technology only; costs associated with increased insurance,
  taxes and maintenance are included in the payback period values.

    An important metric to vehicle purchasers is the payback period 
that can be expected on any new purchase. In other words, there is 
greater willingness to pay for new technology if that new technology 
``pays back'' within an acceptable period of time. The agencies make no 
effort to define the acceptable period of time, but seek to estimate 
the payback period for others to make the decision themselves. The 
payback period is the point at which reduced fuel expenditures outpace 
increased vehicle costs, including increased maintenance, insurance 
premiums and taxes. The payback periods for vehicles meeting the 
standards considered for the final year of implementation (MY2024 for 
alternative 4 and MY2027 for the proposed standards) are shown in Table 
I-12, and are similar for both Method A and Method B.

   Table I-12--Payback Periods for MY2027 Vehicles Under the Proposed
    Standards and for MY2024 Vehicles Under Alternative 4 Relative to
                               Baseline 1a
        [Payback occurs in the year shown; using 7% discounting]
------------------------------------------------------------------------
                                             Proposed
                                             standards     Alternative 4
------------------------------------------------------------------------
Tractors/Trailers.......................             2nd             2nd
Vocational Vehicles.....................             6th             6th
Pickups/Vans............................             3rd             4th
------------------------------------------------------------------------

(3) Cost Effectiveness
    These proposed regulations implement Section 32902(k) of EISA and 
Section 202(a)(1) and (2) of the Clean Air Act. Through the 2007 EISA, 
Congress directed NHTSA to create a medium- and heavy-duty vehicle fuel 
efficiency program designed to achieve the maximum feasible improvement 
by considering appropriateness, cost-effectiveness, and technological 
feasibility to determine maximum feasible standards.\62\ The Clean Air 
Act requires that any air pollutant emission standards for heavy-duty 
vehicles and engines take into account the costs of any requisite 
technology and the lead time necessary to implement such technology. 
Both agencies considered overall costs, overall benefits and cost 
effectiveness in developing the Phase 1 standards. Although there are 
different ways to evaluate cost effectiveness, the essence is to 
consider some measure of costs relative to some measure of impacts.
---------------------------------------------------------------------------

    \62\ This EISA requirement applies to regulation of medium- and 
heavy-duty vehicles. For many years, and as reaffirmed by Congress 
in 2007, ``economic practicability'' has been among the factors EPCA 
requires NHTSA to consider when setting light-duty fuel economy 
standards at the (required) maximum feasible levels. NHTSA 
interprets ``economic practicability'' as a factor involving 
considerations broader than those likely to be involved in ``cost 
effectiveness''.
---------------------------------------------------------------------------

    Considering that Congress enacted EPCA and EISA to, among other 
things, address the need to conserve energy, the agencies have 
evaluated the proposed standards in terms of costs per gallon of fuel 
conserved. As described in the draft RIA, the agencies also evaluated 
the

[[Page 40169]]

proposed standards using the same approaches employed in HD Phase 1. 
Together, the agencies have considered the following three ratios of 
cost effectiveness:
    1. Total costs per gallon of fuel conserved.
    2. Technology costs per ton of GHG emissions reduced.
    3. Technology costs minus fuel savings per ton of GHG emissions 
reduced.
    By all three of these measures, the proposed standards would be 
highly cost effective.
    As discussed below, the agencies estimate that over the lifetime of 
heavy-duty vehicles produced for sale in the U.S. during model years 
2018-2029, the proposed standards would cost about $30 billion and 
conserve about 75 billion gallons of fuel, such that the first measure 
of cost effectiveness would be about 40 cents per gallon. Relative to 
fuel prices underlying the agencies' analysis, the agencies have 
concluded that today's proposed standards would be cost effective.
    With respect to the second measure, which is useful for comparisons 
to other GHG rules, the proposed standards would have overall $/ton 
costs similar to the HD Phase 1 rule. As Chapter 7 of the draft RIA 
shows, technology costs by themselves would amount to less than $50 per 
metric ton of GHG (CO2 eq) for the entire HD Phase 2 
program. This compares well to both the HD Phase 1 rule, which was 
estimated to cost about $30 per metric ton of GHG (without fuel 
savings), and to the agencies' estimates of the social cost of carbon. 
Thus, even without accounting for fuel savings, the proposed standards 
would be cost-effective.
    The third measure deducts fuel savings from technology costs, which 
also is useful for comparisons to other GHG rules. On this basis, net 
costs per ton of GHG emissions reduced would be negative under the 
proposed standards. This means that the value of the fuel savings would 
be greater than the technology costs, and there would be a net cost 
saving for vehicle owners. In other words, the technologies would pay 
for themselves (indeed, more than pay for themselves) in fuel savings.
    In addition, while the net economic benefits (i.e., total benefits 
minus total costs) of the proposed standards is not a traditional 
measure of their cost-effectiveness, the agencies have concluded that 
the total costs of the proposed standards are justified in part by 
their significant economic benefits. As discussed in the previous 
subsection and in Section IX, this rule would provide benefits beyond 
the fuel conserved and GHG emissions avoided. The rule's net benefits 
is a measure that quantifies each of its various benefits in economic 
terms, including the economic value of the fuel it saves and the 
climate-related damages it avoids, and compares their sum to the rule's 
estimated costs. The agencies estimate that the proposed standards 
would result in net economic benefits exceeding $100 billion, making 
this a highly beneficial rule.
    Our current analysis of Alternative 4 also shows that, if 
technologically feasible, it would have similar cost-effectiveness but 
with greater net benefits (see Chapter 11 of the draft RIA). For 
example, the agencies estimate costs under Alternative 4 could be about 
$40 billion and about 85 billion gallons of fuel could be conserved, 
such that the first measure of cost effectiveness would be about 47 
cents per gallon. However, the agencies considered all of the relevant 
factors, not just relative cost-effectiveness, when selecting the 
proposed standards from among the alternatives considered. Relative 
cost-effectiveness was not a limiting factor for the agencies in 
selecting the proposed standards. It is also worth noting that the 
proposed standards and the Alternative 4 standards appear very cost 
effective, regardless of which reference case is used for the baseline, 
such that all of the analyses reinforced the agencies' findings.

E. EPA and NHTSA Statutory Authorities

    This section briefly summarizes the respective statutory authority 
for EPA and NHTSA to promulgate the Phase 1 and proposed Phase 2 
programs. For additional details of the agencies' authority, see 
Section XV of this notice as well as the Phase 1 rule.\63\
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    \63\ 76 FR 57106--57129, September 15, 2011.
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(1) EPA Authority
    Statutory authority for the vehicle controls in this proposal is 
found in CAA section 202(a)(1) and (2) (which requires EPA to establish 
standards for emissions of pollutants from new motor vehicles and 
engines which emissions cause or contribute to air pollution which may 
reasonably be anticipated to endanger public health or welfare), and in 
CAA sections 202(d), 203-209, 216, and 301 (42 U.S.C. 7521 (a)(1) and 
(2), 7521(d), 7522-7543, 7550, and 7601).
    Title II of the CAA provides for comprehensive regulation of mobile 
sources, authorizing EPA to regulate emissions of air pollutants from 
all mobile source categories. When acting under Title II of the CAA, 
EPA considers such issues as technology effectiveness, its cost (both 
per vehicle, per manufacturer, and per consumer), the lead time 
necessary to implement the technology, and based on this the 
feasibility and practicability of potential standards; the impacts of 
potential standards on emissions reductions of both GHGs and non-GHG 
emissions; the impacts of standards on oil conservation and energy 
security; the impacts of standards on fuel savings by customers; the 
impacts of standards on the truck industry; other energy impacts; as 
well as other relevant factors such as impacts on safety.
    This proposed action implements a specific provision from Title II, 
Section 202(a). Section 202(a)(1) of the CAA states that ``the 
Administrator shall by regulation prescribe (and from time to time 
revise) . . . standards applicable to the emission of any air pollutant 
from any class or classes of new motor vehicles . . ., which in his 
judgment cause, or contribute to, air pollution which may reasonably be 
anticipated to endanger public health or welfare.'' With EPA's December 
2009 final findings that certain greenhouse gases may reasonably be 
anticipated to endanger public health and welfare and that emissions of 
GHGs from Section 202(a) sources cause or contribute to that 
endangerment, Section 202(a) requires EPA to issue standards applicable 
to emissions of those pollutants from new motor vehicles. See Coalition 
for Responsible Regulation v. EPA, 684 F. 3d at 116-125, 126-27 cert. 
granted by, in part Util. Air Regulatory Group v. EPA, 134 S. Ct. 418, 
187 L. Ed. 2d 278, 2013 U.S. LEXIS 7380 (U.S., 2013), affirmed in part 
and reversed in part on unrelated grounds by Util. Air Regulatory Group 
v. EPA, 134 S. Ct. 2427, 189 L. Ed. 2d 372, 2014 U.S. LEXIS 4377 (U.S., 
2014) (upholding EPA's endangerment and cause and contribute findings, 
and further affirming EPA's conclusion that it is legally compelled to 
issue standards under Section 202 (a) to address emission of the 
pollutant which endangers after making the endangerment and cause of 
contribute findings); see also id. at 127-29 (upholding EPA's light-
duty GHG emission standards for MYs 2012-2016 in their entirety).
    Other aspects of EPA's legal authority, including it authority 
under Section 202(a), its testing authority under Section 203 of the 
Act, and its enforcement authorities under Section 207 of the Act are 
discussed fully in the Phase 1 rule, and need not be repeated here. See 
76 FR 57129-57130.

[[Page 40170]]

    The proposed rule includes GHG emission and fuel efficiency 
standards applicable to trailers--an essential part of the tractor-
trailer motor vehicle. Class 7/8 heavy-duty vehicles are composed of 
three major components:--The engine, the cab-chassis (i.e. the 
tractor), and the trailer. The fact that the vehicle consists of two 
detachable parts does not mean that either of the parts is not a motor 
vehicle. The trailer's sole purpose is to serve as the cargo-hauling 
part of the vehicle. Without the tractor, the trailer cannot transport 
property. The tractor is likewise incomplete without the trailer. The 
motor vehicle needs both parts, plus the engine, to accomplish its 
intended use. Connected together, a tractor and trailer constitute ``a 
self-propelled vehicle designed for transporting . . . property on a 
street or highway,'' and thus meet the definition of ``motor vehicle'' 
under Section 216(2) of the CAA. Thus, as EPA has previously explained, 
we interpret our authority to regulate motor vehicles to include 
authority to regulate such trailers. See 79 FR 46259 (August 7, 
2014).\64\
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    \64\ Indeed, an argument that a trailer is not a motor vehicle 
because, considered (artificially) as a separate piece of equipment 
it is not self-propelled, applies equally to the cab-chassis--the 
tractor. No entity has suggested that tractors are not motor 
vehicles; nor is such an argument plausible.
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    This analysis is consistent with definitions in the Federal 
regulations issued under the CAA at 40 CFR 86.1803-01, where a heavy-
duty vehicle ``that has the primary load carrying device or container 
attached'' is referred to as a ``[c]omplete heavy-duty vehicle,'' while 
a heavy-duty vehicle or truck ``which does not have the primary load 
carrying device or container attached'' is referred to as an 
``[i]ncomplete heavy- duty vehicle'' or ``[i]ncomplete truck.'' The 
trailers that would be covered by this proposal are properly considered 
``the primary load carrying device or container'' for the heavy-duty 
vehicles to which they become attached for use. Therefore, under these 
definitions, such trailers are implicitly part of a ``complete heavy-
duty vehicle,'' and thus part of a ``motor vehicle.'' 
65 66 67
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    \65\ We note further, however, that certain hauled items, for 
example a boat, would not be considered to be a trailer under the 
proposal. See proposed section 1037.801, proposing to define 
``trailer' as being ``designed for cargo and for being drawn by a 
tractor.''
    \66\ This concept is likewise reflected in the definition of 
``tractor'' in the parallel Department of Transportation 
regulations: ``a truck designed primarily for drawing other motor 
vehicles and not so constructed as to carry a load other than a part 
of the weight of the vehicle and the load so drawn.'' See 49 CFR 
571.3.
    \67\ EPA's proposed definition of ``vehicle'' in 40 CFR 1037.801 
makes clear that an incomplete trailer becomes a vehicle (and thus 
subject to the prohibition against introduction into commerce 
without a certificate) when it has a frame with axles attached. 
Complete trailers are also vehicles.
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    The argument that trailers do not themselves emit pollutants and so 
are not subject to emission standards is also unfounded. First, the 
argument lacks a factual predicate. Trailers indisputably contribute to 
the motor vehicle's CO2 emissions by increasing engine load, 
and these emissions can be reduced through various means such as 
trailer aerodynamic and tire rolling resistance improvements. See 
Section IV below. The argument also lacks a legal predicate. Section 
202(a)(1) authorizes standards applicable to emissions of air 
pollutants ``from'' either the motor vehicle or the engine. There is no 
requirement that pollutants be emitted from a specified part of the 
motor vehicle or engine. And indeed, the argument proves too much, 
since tractors and vocational vehicle chassis likewise contribute to 
emissions (including contributing by the same mechanisms that trailers 
do) but do not themselves directly emit pollutants. The fact that 
Section 202(a)(1) applies explicitly to both motor vehicles and engines 
likewise indicates that EPA has unquestionable authority to interpret 
pollutant emission caused by the vehicle component to be ``from'' the 
motor vehicle and so within its regulatory authority under Section 
202(a)(1).\68\
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    \68\ This argument applies equally to emissions of criteria 
pollutants, whose rate of emission is likewise affected by vehicle 
characteristics. It is for this reason that EPA's implementing rules 
for criteria pollutants from heavy duty vehicles and engines specify 
a test weight for certification testing, since that weight 
influences the amount of pollution emission.
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(2) NHTSA Authority
    The Energy Policy and Conservation Act (EPCA) of 1975 mandates a 
regulatory program for motor vehicle fuel economy to meet the various 
facets of the need to conserve energy. In December 2007, Congress 
enacted the Energy Independence and Security Act (EISA), amending EPCA 
to require, among other things, the creation of a medium- and heavy-
duty fuel efficiency program for the first time.
    Statutory authority for the fuel consumption standards in this 
proposed rule is found in EISA section 103, 49 U.S.C. 32902(k). This 
section authorizes a fuel efficiency improvement program, designed to 
achieve the maximum feasible improvement to be created for commercial 
medium- and heavy-duty on-highway vehicles and work trucks, to include 
appropriate test methods, measurement metrics, standards, and 
compliance and enforcement protocols that are appropriate, cost-
effective and technologically feasible.
    NHTSA has responsibility for fuel economy and consumption 
standards, and assures compliance with EISA through rulemaking, 
including standard-setting; technical reviews, audits and studies; 
investigations; and enforcement of implementing regulations including 
penalty actions. This proposed rule would continue to fulfill the 
requirements of Section 103 of EISA, which instructs NHTSA to create a 
fuel efficiency improvement program for ``commercial medium- and heavy-
duty on-highway vehicles and work trucks'' by rulemaking, which is to 
include standards, test methods, measurement metrics, and enforcement 
protocols. See 49 U.S.C. 32902(k)(2).
    Congress directed that the standards, test methods, measurement 
metrics, and compliance and enforcement protocols be ``appropriate, 
cost-effective, and technologically feasible'' for the vehicles to be 
regulated, while achieving the ``maximum feasible improvement'' in fuel 
efficiency. NHTSA has broad discretion to balance the statutory factors 
in Section 103 in developing fuel consumption standards to achieve the 
maximum feasible improvement.
    As discussed in the Phase 1 final rule notice, NHTSA has determined 
that the five year statutory limit on average fuel economy standards 
that applies to passengers and light trucks is not applicable to the HD 
vehicle and engine standards. As a result, the Phase 1 HD engine and 
vehicle standards remain in effect indefinitely at their 2018 or 2019 
MY levels until amended by a future rulemaking action. As was 
contemplated in that notice, NHTSA is currently engaging in this Phase 
2 rulemaking action. Therefore, the Phase 1 standards would not remain 
in effect at their 2018 or 2019 MY levels indefinitely; they would 
remain in effect until the MY Phase 2 standards apply. In accordance 
with Section 103 of EISA, NHTSA will ensure that not less than four 
full MYs of regulatory lead-time and three full MYs of regulatory 
stability are provided for in the Phase 2 standards.
(a) Authority To Regulate Trailers
    As contemplated in the Phase 1 proposed and final rules, the 
agencies are proposing standards for trailers in this rulemaking. 
Because Phase 1 did not include standards for trailers, NHTSA did not 
discuss its authority for regulating them in the proposed or final 
rules; that authority is described here.

[[Page 40171]]

    EISA directs NHTSA to ``determine in a rulemaking proceeding how to 
implement a commercial medium- and heavy-duty on-highway vehicle and 
work truck fuel efficiency improvement program designed to achieve the 
maximum feasible improvement. . . .'' EISA defines a commercial medium- 
and heavy-duty on-highway vehicle to mean ``an on-highway vehicle with 
a GVWR of 10,000 lbs or more.'' A ``work truck'' is defined as a 
vehicle between 8,500 and 10,000 lbs GVWR that is not an MDPV. These 
definitions do not explicitly exclude trailers, in contrast to MDPVs. 
Because Congress did not act to exclude trailers when defining GVWRs, 
despite demonstrating the ability to exclude MDPVs, it is reasonable to 
interpret the provision to include them.
    Both commercial medium- and heavy-duty on-highway vehicles and work 
trucks, though, must be vehicles in order to be regulated under this 
program. Although EISA does not define the term ``vehicle,'' NHTSA's 
authority to regulate motor vehicles under its organic statute, the 
Motor Vehicle Safety Act (``Safety Act''), does. The Safety Act defines 
a motor vehicle as ``a vehicle driven or drawn by mechanical power and 
manufactured primarily for use on public streets, roads, and highways. 
. . .'' NHTSA clearly has authority to regulate trailers under this Act 
as vehicles that are drawn and has exercised that authority numerous 
times. Given the absence of any apparent contrary intent on the part of 
Congress in EISA, NHTSA believes it is reasonable to interpret the term 
``vehicle'' as used in the EISA definitions to have a similar meaning 
that includes trailers.
    Furthermore, the general definition of a vehicle is something used 
to transport goods or persons from one location to another. A tractor-
trailer is designed for the purpose of transporting goods. Therefore it 
is reasonable to consider all of its parts--the engine, the cab-
chassis, and the trailer--as parts of a whole. As such they are all 
parts of a vehicle, and are captured within the definition of vehicle. 
As EPA describes above, the tractor and trailer are both incomplete 
without the other. Neither can fulfill the function of the vehicle 
without the other. For this reason, and the other reasons stated above, 
NHTSA interprets its authority to regulate commercial medium- and 
heavy-duty on-highway vehicles, including tractor-trailers, as 
encompassing both tractors and trailers.
(b) Authority To Regulate Recreational Vehicles
    NHTSA did not regulate recreational vehicles as part of the Phase 1 
medium- and heavy-duty fuel consumption standards, although EPA did 
regulate them as vocational vehicles for GHG emissions.\69\ In the 
Phase 1 proposed rule, NHTSA interpreted ``commercial medium- and heavy 
duty'' to mean that recreational vehicles, such as motor homes, were 
not to be included within the program because recreational vehicles are 
not commercial. Oshkosh Corporation submitted a comment on the agency's 
interpretation stating that it did not match the statutory definition 
of ``commercial medium- and heavy-duty on-highway vehicle,'' which 
defines the phrase by GVWR and on-highway use. In the Phase 1 final 
rule NHTSA agreed with Oshkosh Corporation that the agency had 
effectively read words into the statutory definition. However, because 
recreational vehicles were not proposed in the Phase 1 proposed rule, 
they were not within the scope of the rulemaking and were excluded from 
NHTSA's standards.\70\ NHTSA expressed that it would address 
recreational vehicles in its next rulemaking.
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    \69\ EPA did not give special consideration to recreational 
vehicles because the CAA applies to heavy-duty motor vehicle 
generally.
    \70\ Motor homes are still subject to EPA's Phase 1 
CO2 standards for vocational vehicles.
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    NHTSA is proposing that recreational vehicles be included in the 
Phase 2 fuel consumption standards. As discussed above, EISA prescribes 
that NHTSA shall set average fuel economy standards for work trucks and 
commercial medium-duty or heavy-duty on-highway vehicles. ``Work 
truck'' means a vehicle that is rated between 8,500 and 10,000 lbs GVWR 
and is not an MDPV. ``Commercial medium- and heavy-duty on-road highway 
vehicle'' means an on-highway vehicle with a gross vehicle weight 
rating of 10,000 lbs or more.\71\ Based on the definitions in EISA, 
recreational vehicles would be regulated as class 2b-8 vocational 
vehicles. Excluding recreational vehicles from the NHTSA standards in 
Phase 2 could create illogical results, including treating similar 
vehicles differently. Moreover, including recreational vehicles under 
NHTSA regulations furthers the agencies' goal of one national program, 
as EPA regulations already cover recreational vehicles.
---------------------------------------------------------------------------

    \71\ 49 U.S.C. 32901(a)(7).
---------------------------------------------------------------------------

    NHTSA is proposing that recreational vehicles be included in the 
Phase 2 fuel consumption standards and that early compliance be allowed 
for manufacturers who want to certify during the Phase 1 period.\72\
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    \72\ NHTSA did not allow early compliance for one RV 
manufacturer in MY 2014 that is currently complying EPA's GHG 
standards.
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F. Other Issues

    In addition to the standards being proposed, this notice discusses 
several other issues related to those standards. It also proposes some 
regulatory provisions related to the Phase 1 program, as well as 
amendments related to other EPA and NHTSA regulations. These other 
issues are summarized briefly here and discussed in greater detail in 
later sections.
(1) Issues Related to Phase 2
(a) Natural Gas Engines and Vehicles
    This combined rulemaking by EPA and NHTSA is designed to regulate 
two separate characteristics of heavy duty vehicles: GHGs and fuel 
consumption. In the case of diesel or gasoline powered vehicles, there 
is a one-to-one relationship between these two characteristics. For 
alternatively fueled vehicles, which use no petroleum, the situation is 
different. For example, a natural gas vehicle that achieves 
approximately the same fuel efficiency as a diesel powered vehicle 
would emit 20 percent less CO2; and a natural gas vehicle 
with the same fuel efficiency as a gasoline vehicle would emit 30 
percent less CO2. Yet natural gas vehicles consume no 
petroleum. In Phase 1, the agencies balanced these facts by applying 
the gasoline and diesel CO2 standards to natural gas engines 
based on the engine type of the natural gas engine. Fuel consumption 
for these vehicles is then calculated according to their tailpipe 
CO2 emissions. In essence, this applies a one-to-one 
relationship between fuel efficiency and tailpipe CO2 
emissions for all vehicles, including natural gas vehicles. The 
agencies determined that this approach would likely create a small 
balanced incentive for natural gas use. In other words, it created a 
small incentive for the use of natural gas engines that appropriately 
balanced concerns about the climate impact methane emissions against 
other factors such as the energy security benefits of using domestic 
natural gas. See 76 FR 57123. We propose to maintain this approach for 
Phase 2. Note that EPA is also considering natural gas in a broader 
context of life cycle emissions, as described in Section XI.
(b) Alternative Refrigerants
    In addition to use of leak-tight components in air conditioning 
system

[[Page 40172]]

design, manufacturers could also decrease the global warming impact of 
refrigerant leakage emissions by adopting systems that use alternative, 
lower global warming potential (GWP) refrigerants, to replace the 
refrigerant most commonly used today, HFC-134a (R-134a). HFC-134a is a 
potent greenhouse gas with a GWP 1,430 times greater than that of 
CO2.
    Under EPA's Significant New Alternatives Policy (SNAP) Program,\73\ 
EPA has found acceptable, subject to use conditions, three alternative 
refrigerants that have significantly lower GWPs than HFC-134a for use 
in A/C systems in newly manufactured light-duty vehicles: HFC-152a, 
CO2 (R-744), and HFO-1234yf.\74\ HFC-152a has a GWP of 124, 
HFO-1234yf has a GWP of 4, and CO2 (by definition) has a GWP 
of 1, as compared to HFC-134a which has a GWP of 1,430.\75\ 
CO2 is nonflammable, while HFO-1234yf and HFC-152a are 
flammable. All three are subject to use conditions requiring labeling 
and the use of unique fittings, and where appropriate, mitigating 
flammability and toxicity. Currently, the SNAP listing for HFO-1234yf 
is limited to newly manufactured A/C systems in LD vehicles, whereas 
HFC-152a and CO2 have been found acceptable for all motor 
vehicle air conditioning applications, including heavy-duty vehicles.
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    \73\ Section 612(c) of the Clean Air Act requires EPA to review 
substitutes for class I and class II ozone-depleting substances and 
to determine whether such substitutes pose lower risk than other 
available alternatives. EPA is also required to publish lists of 
substitutes that it determines are acceptable and those it 
determines are unacceptable. See http://www.epa.gov/ozone/snap/refrigerants/lists/index.html, last accessed on March 5, 2015.
    \74\ Listed at 40 CFR part 82, subpart G.
    \75\ GWP values cited in this proposal are from the IPCC Fourth 
Assessment Report (AR4) unless stated otherwise. Where no GWP is 
listed in AR4, GWP values shall be determined consistent with the 
calculations and analysis presented in AR4 and referenced materials.
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    None of these alternative refrigerants can simply be ``dropped'' 
into existing HFC-134a air conditioning systems. In order to account 
for the unique properties of each refrigerant and address use 
conditions required under SNAP, changes to the systems will be 
necessary. Typically these changes will need to occur during a vehicle 
redesign cycle but could also occur during a refresh. For example, 
because CO2, when used as a refrigerant, is physically and 
thermodynamically very different from HFC-134a and operates at much 
higher pressures, a transition to this refrigerant would require 
significant hardware changes. A transition to A/C systems designed for 
HFO-1234yf, which is more thermodynamically similar to HFC-134a than is 
CO2, requires less significant hardware changes that 
typically include installation of a thermal expansion valve and could 
potentially require resized condensers and evaporators, as well as 
changes in other components. In addition, vehicle assembly plants 
require re-tooling in order to handle new refrigerants safely. Thus a 
change in A/C refrigerants requires significant engineering, planning, 
and manufacturing investments.
    EPA is not aware of any significant development of A/C systems 
designed to use alternative refrigerants in heavy-duty vehicles; \76\ 
however, all three lower GWP alternatives are in use or under various 
stages of development for use in LD vehicles. Of these three 
refrigerants, most manufacturers of LD vehicles have identified HFO-
1234yf as the most likely refrigerant to be used in that application. 
For that reason, EPA would anticipate that HFO-1234yf could be a 
primary candidate for refrigerant substitution in the HD market in the 
future if it is listed as an acceptable substitute under SNAP for HD A/
C applications. EPA has begun, but has not yet completed, our 
evaluation of the use of HFO-1234yf in HD vehicles. After EPA has 
conducted a full evaluation based on the SNAP program's comparative 
risk framework, EPA will list this alternative as either a) acceptable 
subject to use conditions or b) unacceptable if the risk of use in HD 
A/C systems is determined to be greater than that of the other 
currently or potentially available alternatives. EPA is also 
considering and evaluating additional refrigerant substitutes for use 
in motor vehicle A/C systems under the SNAP program. EPA welcomes 
comments related to industry development of HD A/C systems using lower-
GWP refrigerants.
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    \76\ To the extent that some manufacturers produce HD pickups 
and vans on the same production lines or in the same facilities as 
LD vehicles, some A/C system technology commonality between the two 
vehicle classes may be developing.
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    LD vehicle manufacturers are currently making investments in 
systems designed for lower-GWP refrigerants, both domestically and on a 
global basis. In support of the LD GHG rule, EPA projected a full 
transition of LD vehicles to lower-GWP alternatives in the United 
States by MY 2021. We expect the investment required to transition to 
ease over time as alternative refrigerants are adopted across all LD 
vehicles and trucks. This may occur in part due to increased 
availability of components and the continuing increases in refrigerant 
production capacity, as well as knowledge gained through experience. As 
lower-GWP alternatives become widely used in LD vehicles, some 
manufacturers may wish to also transition their HD vehicles. 
Transitioning could be advantageous for a variety of reasons including 
platform standardization and company environmental stewardship 
policies.
    Although manufacturers of HD vehicles may begin to transition to 
alternative refrigerants in the future, there is great uncertainty 
about when significant adoption of alternative refrigerants for HD 
vehicles might begin, on what timeline adoption might become 
widespread, and which refrigerants might be involved. Another factor is 
that the most likely candidate, HFO-1234yf, remains under evaluation 
and has not yet been listed under SNAP. For these reasons, EPA has not 
attempted to project any specific hypothetical scenarios of transition 
for analytical purposes in this proposed rule.
    Because future introduction of and transition to lower-GWP 
alternative refrigerants for HD vehicles may occur, EPA is proposing 
regulatory provisions that would be in place if and when such 
alternatives become available and manufacturers of HD vehicles choose 
to use them. These proposed provisions would also have the effect of 
easing the burden associated with complying with the lower-leakage 
requirements when a lower-GWP refrigerant is used instead of HFC-134a. 
These provisions would recognize that leakage of refrigerants would be 
relatively less damaging from a climate perspective if one of the 
lower-GWP alternatives is used. Specifically, EPA is proposing to allow 
a manufacturer to be ``deemed to comply'' with the leakage standard by 
using a lower-GWP alternative refrigerant. In order to be ``deemed to 
comply'' the vehicle manufacturer would need to use a refrigerant other 
than HFC-134a that is listed as an acceptable substitute refrigerant 
for heavy-duty A/C systems under SNAP, and defined under the LD GHG 
regulations at 40 CFR 86.1867-12(e). The refrigerants currently defined 
at 40 CFR 86.1867-12(e), besides HFC-134a, are HFC-152a, HFO-1234yf, 
and CO2. If a manufacturer chooses to use a lower-GWP 
refrigerant that is listed in the future as acceptable in 40 CFR part 
82, subpart G, but that is not identified in 40 CFR 86.1867-12(e), then 
the manufacturer could contact EPA about how to appropriately determine 
compliance with the leakage standard.
    EPA encourages comment on all aspects of our proposed approach to 
HD

[[Page 40173]]

vehicle refrigerant leakage and the potential future use of alternative 
refrigerants for HD applications. We specifically request comment on 
whether there should be additional provisions that could prevent or 
discourage manufacturers that transition to an alternative refrigerant 
from discontinuing existing, low-leak A/C system components and instead 
reverting to higher-leakage components.
    Recently, EPA proposed to change the SNAP listing for the 
refrigerant HFC-134a from acceptable (subject to use conditions) to 
unacceptable for use in A/C systems in new LD vehicles.\77\ EPA expects 
to take final action on this proposed change in listing status for HFC-
134a for use in new, light-duty vehicles in 2015. If the final action 
changes the status of HFC-134a to unacceptable, it would establish a 
future compliance date by which HFC-134a could no longer be used in A/C 
systems in newly manufactured LD vehicles; instead, all A/C systems in 
new LD vehicles would be required to use HFC-152a, HFO-1234yf, 
CO2, or any other alternative listed as acceptable for this 
use in the future. The current proposed rule does not address the use 
of HFC-134a in heavy-duty vehicles; however, EPA could consider a 
change of listing status for HFC-134a use in HD vehicles in the future 
if EPA determines that other alternatives are currently or potentially 
available that pose lower overall risk to human health and the 
environment.
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    \77\ See 79 FR 46126, August 6, 2014.
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(c) Small Business Issues
    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
rule will not have a significant economic impact on a substantial 
number of small entities. See generally 5 U.S.C. Sections 601-612. The 
RFA analysis is discussed in Section XIV.
    Pursuant to Section 609(b) of the RFA, as amended by the Small 
Business Regulatory Enforcement Fairness Act (SBREFA), EPA also 
conducted outreach to small entities and convened a Small Business 
Advocacy Review Panel to obtain advice and recommendations of 
representatives of the small entities that potentially would be subject 
to the rule's requirements. Consistent with the RFA/SBREFA 
requirements, the Panel evaluated the assembled materials and small-
entity comments on issues related to elements of the IRFA. A copy of 
the Panel Report is included in the docket for this proposed rule.
    The agencies determined that the proposed Phase 2 regulations could 
have a significant economic impact on small entities. Specifically, the 
agencies identified four categories of directly regulated small 
businesses that could be impacted:

 Trailer Manufacturers
 Alternative Fuel Converters
 Vocational Chassis Manufacturers
 Glider Vehicle \78\ Assemblers

    \78\ Vehicles produced by installing a used engine into a new 
chassis are commonly referred to as ``gliders,'' ``glider kits,'' or 
``glider vehicles,''
---------------------------------------------------------------------------

    To minimize these impacts the agencies are proposing certain 
regulatory flexibilities--both general and category-specific. In 
general, we are proposing to delay new requirements for EPA GHG 
emission standards by one year and simplify certification requirements 
for small businesses. For the proposed trailers standards, small 
businesses would be required to comply with EPA's standards before 
NHTSA's fuel efficiency standards would begin. NHTSA does not believe 
that providing small businesses trailer manufacturers with an 
additional year of delay to comply with those fuel efficiency standards 
would provide beneficial flexibility. The agencies are also proposing 
the following specific relief:
     Trailers: Proposing simpler requirements for non-box 
trailers, which are more likely to be manufactured by small businesses; 
and making third-party testing easier for certification.
     Alternative Fuel Converters: Omitting recertification of a 
converted vehicle when the engine is converted and certified; reduced 
N2O testing; and simplified onboard diagnostics and delaying 
required compliance with each new standard by one model year.
     Vocational Chassis: Less stringent standards for certain 
vehicle categories.
     Glider Vehicle Assemblers: \79\ Exempt existing small 
businesses, but limit the small business exemption to a capped level of 
annual production (production in excess of the capped amount would be 
allowed, but subject to all otherwise applicable requirements including 
the Phase 2 standards).

    \79\ EPA is proposing to amend its rules applicable to engines 
installed in glider kits, a proposal which would affect emission 
standards not only for GHGs but for criteria pollutants as well. EPA 
is also proposing to clarify its requirements for certification and 
revise its definitions for glider manufacturers. NHTSA is also 
considering including gliders under its Phase 2 standards.
---------------------------------------------------------------------------

These flexibilities are described in more detail in Section XIV and in 
the Panel Report. The agencies look forward to comments and to feedback 
from the small business community before finalizing the rule and 
associated flexibilities to protect small businesses.
(d) Confidentiality of Test Results and GEM Inputs
    In accordance with Federal statutes, EPA does not release 
information from certification applications (or other compliance 
reports) that we determine to be confidential business information 
(CBI) under 40 CFR part 2. Consistent with the CAA, EPA does not 
consider emission test results to be CBI after introduction into 
commerce of the certified engine or vehicle. (However, we have 
generally treated test results as protected before the introduction 
into commerce date). For Phase 2, we expect to continue this policy and 
thus would not treat any test results or other GEM inputs as CBI after 
the introduction into commerce date as identified by the manufacturer. 
We request comment on this approach.
    We consider this issue to be especially relevant for tire rolling 
resistance measurements. Our understanding is that tire manufacturers 
typically consider such results as proprietary. However, under EPA's 
policy, tire rolling resistance measurements are not considered to be 
CBI and can be released to the public after the introduction into 
commerce date identified by the manufacturer. We request comment on 
whether EPA should release such data on a regular basis to make it 
easier for operators to find proper replacement tires for their 
vehicles.
    With regard to NHTSA's treatment of confidential business 
information, manufacturers must submit a request for confidentiality 
with each electronic submission specifying any part of the information 
or data in a report that it believes should be withheld from public 
disclosure as trade secret or other confidential business information. 
A form will be available through the NHTSA Web site to request 
confidentiality. NHTSA does not consider manufacturers to continue to 
have a business case for protecting pre-model report data after the 
vehicles contained within that report have been introduced into 
commerce.
(e) Delegated Assembly
    In EPA's existing regulations (40 CFR 1068.261), we allow engine 
manufacturers to sell or ship engines that are missing certain 
emission-related components if those components will be installed by 
the vehicle manufacturer. EPA has found this provision to work well for 
engine manufacturers and is proposing a new provision in 40 CFR

[[Page 40174]]

1037.621 that would provide a similar allowance for vehicle 
manufacturers to sell or ship vehicles that are missing certain 
emission-related components if those components will be installed by a 
secondary vehicle manufacturer. As conditions of this allowance 
manufacturers would be required to:
     Have a contractual obligation with the secondary 
manufacturer to complete the assembly properly and provide instructions 
about how to do so.
     Keep records to demonstrate compliance.
     Apply a temporary label to the incomplete vehicles.
     Take other reasonable steps to ensure the assembly is 
completed properly.
     Describe in its application for certification how it will 
use this allowance.
    We request comment on this allowance.
(2) Proposed Amendments to Phase 1 Program
    The agencies are proposing revisions to test procedures and 
compliance provisions used for Phase 1. These changes are described in 
Section XII. As a drafting matter, EPA notes that we are proposing to 
migrate the GHG standards for Class 2b and 3 pickups and vans from 40 
CFR 1037.104 to 40 CFR 86.1819-14. NHTSA is also proposing to amend 49 
CFR part 535 to make technical corrections to its Phase 1 program to 
better align with EPA's compliance approach, standards and 
CO2 performance results. In general, these changes are 
intended to improve the regulatory experience for regulated parties and 
also reduce agency administrative burden. More specifically, NHTSA 
proposes to change the rounding of its standards and performance values 
to have more significant digits. Increasing the number of significant 
digits for values used for compliance with NHTSA standards reduces 
differences in credits generated and overall credit balances for the 
NHTSA and EPA programs. NHTSA is also proposing to remove the 
petitioning process for off-road vehicles, clarify requirements for the 
documentation needed for submitting innovative technology requests in 
accordance with 40 CFR 1037.610 and 49 CFR 535.7, and add further 
detail to requirements for submitting credit allocation plans as 
specified in 49 CFR 535.9. Finally, NHTSA is adding the same record 
requirements that EPA currently requires to facilitate in-use 
compliance inspections. These changes are intended to improve the 
regulatory experience for regulated parties and also reduce agency 
administrative burden.
(3) Other Proposed Amendments to EPA Regulations
    EPA is proposing several amendments to regulations not directly 
related to the HD Phase 1 or Phase 2 programs, as detailed in Section 
XIII. For these amendments, there would not be corresponding changes in 
NHTSA regulations (since there are no such regulations relevant to 
those programs). Some of these relate directly to heavy-duty highway 
engines, but not to the GHG programs. Others relate to nonroad engines. 
This latter category reflects the regulatory structure EPA uses for its 
mobile source regulations, in which regulatory provisions applying 
broadly to different types of mobile sources are codified in common 
regulatory parts such as 40 CFR part 1068. This approach creates a 
broad regulatory structure that regulates highway and nonroad engines, 
vehicles, and equipment collectively in a common program. Thus, it is 
appropriate to include some proposed amendments to nonroad regulations 
in addition to the changes proposed only for highway engines and 
vehicles.
(a) Standards for Engines Used In Glider Kits
    EPA regulations currently allow used pre-2013 engines to be 
installed into new glider kits without meeting currently applicable 
standards. As described in Section XIV, EPA is proposing to amend our 
regulations to allow only engines that have been certified to meet 
current standards to be installed in new glider kits, with two 
exceptions. First, engines certified to earlier MY standards that were 
identical to the current model year standards may be used. Second, the 
small manufacturer allowance described in Section I.F.(1)(c) for glider 
vehicles would also apply for the engines used in the exempted glider 
kits.
(b) Re-Proposal of Nonconformance Penalty Process Changes
    Nonconformance penalties (NCPs) are monetary penalties established 
by regulation that allow a vehicle or engine manufacturer to sell 
engines that do not meet the emission standards. Manufacturers unable 
to comply with the applicable standard pay penalties, which are 
assessed on a per-engine basis.
    On September 5, 2012, EPA adopted final NCPs for heavy heavy-duty 
diesel engines that could be used by manufacturers of heavy-duty diesel 
engines unable to meet the current oxides of nitrogen (NOX) 
emission standard. On December 11, 2013 the U.S. Court of Appeals for 
the District of Columbia Circuit issued an opinion vacating that Final 
Rule. It issued its mandate for this decision on April 16, 2014, ending 
the availability of the NCPs for the current NOX standard, 
as well as vacating certain amendments to the NCP regulations due to 
concerns about inadequate notice. In particular, the amendments revise 
the text explaining how EPA determines when NCP should be made 
available. In this action, EPA is re-proposing most of these amendments 
to provide fuller notice and additional opportunity for public comment. 
They are discussed in Section XIV.
(c) Updates to Heavy-Duty Engine Manufacturer In-Use Testing 
Requirements
    EPA and manufacturers have gained substantial experience with in-
use testing over the last four or five years. This has led to important 
insights in ways that the test protocol can be adjusted to be more 
effective. We are accordingly proposing to make changes to the 
regulations in 40 CFR part 86, subparts N and T.
(d) Extension of Certain 40 CFR Part 1068 Provisions to Highway 
Vehicles and Engines
    As part of the Phase 1 GHG standards, we applied the exemption and 
importation provisions from 40 CFR part 1068, subparts C and D, to 
heavy-duty highway engines and vehicles. We also specified that the 
defect reporting provisions of 40 CFR 1068.501 were optional. In an 
earlier rulemaking, we applied the selective enforcement auditing under 
40 CFR part 1068, subpart E (75 FR 22896, April 30, 2010). We are 
proposing in this rule to adopt the rest of 40 CFR part 1068 for heavy-
duty highway engines and vehicles, with certain exceptions and special 
provisions.
    As described above, we are proposing to apply all the general 
compliance provisions of 40 CFR part 1068 to heavy-duty engines and 
vehicles. We propose to also apply the recall provisions and the 
hearing procedures from 40 CFR part 1068 for highway motorcycles and 
for all vehicles subject to standards under 40 CFR part 86, subpart S. 
We also request comment on applying the rest of the provisions from 40 
CFR part 1068 to highway motorcycles and to all vehicles subject to 
standards under 40 CFR part 86, subpart S.
    EPA is proposing to update and consolidate the regulations related 
to

[[Page 40175]]

formal and informal hearings in 40 CFR part 1068, subpart G. This would 
allow us to rely on a single set of regulations for all the different 
categories of vehicles, engines, and equipment that are subject to 
emission standards. We also made an effort to write these regulations 
for improved readability.
    We are also proposing to make a number of changes to part 1068 to 
correct errors, to add clarification, and to make adjustments based on 
lessons learned from implementing these regulatory provisions.
(e) Amendments to Engine and Vehicle Test Procedures in 40 CFR Parts 
1065 and 1066
    EPA is proposing several changes to our engine testing procedures 
specified in 40 CFR part 1065. None of these changes would 
significantly impact the stringency of any standards.
(f) Amendments Related to Marine Diesel Engines in 40 CFR Parts 1042 
and 1043
    EPA's emission standards and certification requirements for marine 
diesel engines under the Clean Air Act and the act to Prevent Pollution 
from Ships are identified in 40 CFR parts 1042 and 1043, respectively. 
EPA is proposing to amend these regulations with respect to continuous 
NOX monitoring and auxiliary engines, as well as making 
several other minor revisions.
(g) Amendments Related to Locomotives in 40 CFR Part 1033
    EPA's emission standards and certification requirements for 
locomotives under the Clean Air Act are identified in 40 CFR part 1033. 
EPA is proposing to make several minor revisions to these regulations.
(4) Other Proposed Amendments to NHTSA Regulations
    NHTSA is proposing to amend 49 CFR parts 512 and 537 to allow 
manufacturers to submit required compliance data for the Corporate 
Average Fuel Economy program electronically, rather than submitting 
some reports to NHTSA via paper and CDs and some reports to EPA through 
its VERIFY database system. The agencies are coordinating on an 
information technology project which will allow manufacturers to submit 
pre-model, mid-model and final model year reports through a single 
electronic entry point. The agencies anticipate that this would reduce 
the reporting burden on manufacturers by up to fifty percent. The 
amendments to 49 CFR part 537 would allow reporting to an electronic 
database (i.e. EPA's VERIFY system), and the amendments to 49 CFR part 
512 would ensure that manufacturer's confidential business information 
would be protected through that process. This proposal is discussed 
further in Section XIII.

II. Vehicle Simulation, Engine Standards and Test Procedures

A. Introduction and Summary of Phase 1 and Phase 2 Regulatory 
Structures

    This Section II. A. gives an overview of our vehicle simulation 
approach in Phase 1 and our proposed approach for Phase 2; our separate 
engine standards for tractor and vocational chassis in Phase 1 and our 
proposed separate engine standards in Phase 2; and it describes our 
engine and vehicle test procedures that are common among the tractor 
and vocational chassis standards. Section II. B. discusses in more 
detail how the Phase 2 proposed regulatory structure would approach 
vehicle simulation, separate engine standards, and test procedures. 
Section II. C. discusses the proposed vehicle simulation computer 
program, GEM, in further detail and Section II. D. discusses the 
proposed separate engine standards and engine test procedure. See 
Sections III through VI for discussions of the proposed test procedures 
that are unique for tractors, trailers, vocational chassis, and HD 
pickup trucks and vans.
    In Phase 1 the agencies adopted a regulatory structure that 
included a vehicle simulation procedure for certifying tractors and the 
chassis of vocational vehicles. In contrast, the agencies adopted a 
full vehicle chassis dynamometer test procedure for certifying complete 
heavy-duty pickups and vans. The Phase 1 vehicle simulation procedure 
for tractors and vocational chassis requires regulated entities to use 
GEM to simulate and certify tractors and vocational vehicle chassis. 
This program is provided free of charge for unlimited use and may be 
downloaded by anyone from EPA's Web site: http://www.epa.gov/otaq/climate/gem.htm. This computer program mathematically combines vehicle 
component test results with other pre-determined vehicle attributes to 
determine a vehicle's levels of fuel consumption and CO2 
emissions for certification purposes. For Phase 1, the required inputs 
to this computer program include, for tractors, vehicle aerodynamics 
information, tire rolling resistance, and whether or not a vehicle is 
equipped with certain lightweight high-strength steel or aluminum 
components, a tamper-proof speed limiter, or tamper-proof idle 
reduction technologies. The sole input for vocational vehicles, was 
tire rolling resistance. For Phase 1 the computer program's inputs did 
not include engine test results or attributes related to a vehicle's 
powertrain, namely, its transmission, drive axle(s), or tire 
revolutions per mile. Instead, for Phase 1 the agencies specified a 
generic engine and powertrain within the computer program, and for 
Phase 1 these cannot be changed by a program user.\80\
---------------------------------------------------------------------------

    \80\ These attributes are recognized in Phase 1 innovative 
technology provisions at 40 CFR 1037.610.
---------------------------------------------------------------------------

    The full vehicle chassis dynamometer test procedure for heavy-duty 
pickups and vans substantially mirrors EPA's existing light-duty 
vehicle test procedure. EPA also set separate engine so-called cap 
standards for methane (CH4) and nitrous oxide 
(N2O) (essentially capping current emission levels). 
Compliance with the CH4 and N2O standards is 
measured by an engine dynamometer test procedure, which EPA based on 
our existing heavy-duty engine emissions test procedure with small 
adaptations. EPA also set hydro-fluorocarbon refrigerant leakage design 
standards for cabin air conditioning systems in tractors, pickups, and 
vans, which are evaluated by design rather than a test procedure.
    In this action the agencies are proposing a similar regulatory 
structure for Phase 2, along with a number of revisions that are 
intended to more accurately evaluate vehicle and engine technologies' 
impact on real-world fuel efficiency and GHG emissions. Thus, we are 
proposing to continue the same certification test regime for heavy duty 
pickups and vans, and for the CH4 and N2O) 
standards, as well as tractor and pickup and van air conditioning 
leakage standards. EPA is also proposing to control vocational vehicle 
air conditioning leakage and to use that same certification procedure.
    We are proposing to continue the vehicle simulation procedure for 
certifying tractors and vocational chassis, and we are proposing a new 
regulatory program to regulate some of the trailers hauled by tractors. 
The agencies are proposing the use of an equation based on the vehicle 
simulation procedure for trailer certification. In addition, we are 
proposing a simplified option for trailer certification that would not 
require testing to be undertaken by manufacturers to generate inputs 
for the equation. We are also proposing to continue separate fuel 
consumption and CO2 standards for the engines installed

[[Page 40176]]

in tractors and vocational chassis, and we are proposing to continue to 
require a full vehicle chassis dynamometer test procedure for 
certifying complete heavy-duty pickups and vans. As described in 
Section II.B.(2)(b), the agencies see important advantages to 
maintaining separate engines standards, such as improved compliance 
assurance and better control during transient engine operation.
    The vehicle simulation procedure necessitates some testing of 
engines and vehicle components to generate the inputs for the 
simulation tool; that is, to generate the inputs to the model which is 
used to certify tractors and vocational chassis. For trailers, some 
testing may be performed in order to generate values that are input 
into the simulation-based compliance equations. In addition to the 
testing needed for this purpose for the inputs used in the Phase 1 
standards, the agencies are proposing in Phase 2 that manufacturers 
conduct additional required and optional engine and vehicle component 
tests, and proposing the additional procedures for conducting these 
input tests. These include a new required engine test procedure that 
provides steady-state engine fuel consumption and CO2 inputs 
to represent the actual engine in a vehicle. In addition, we are 
seeking comment on a newly developed engine test procedure that 
captures transient engine performance for use in the vehicle simulation 
computer program. As described in detail in the draft RIA Chapter 4, we 
are proposing to require entering attributes that describe the 
vehicle's transmission type, and its number of gears and gear ratios. 
We are proposing an optional powertrain test procedure that would 
provide inputs to override the agencies' simulated engine and 
transmission in the vehicle simulation computer program. We are 
proposing to require entering attributes that describe the vehicle's 
drive axle(s) type and axle ratio. We are also seeking comment on an 
optional axle efficiency test procedure that would override the 
agencies' simulated axle in the vehicle simulation computer program. To 
improve the measurement of aerodynamic components performance, we are 
proposing a number of improvements to the aerodynamic coast-down test 
procedure and data analysis, and we are seeking comment on a newly 
developed constant speed aerodynamic test procedure. We are proposing 
that the aerodynamic test procedures for tractors be applicable to 
trailers when a regulated entity opts to use the GEM-based compliance 
equation. Additional details about all these test procedures are found 
in the draft RIA Chapter 3.
    We are further proposing to significantly expand the number of 
technologies that are recognized in the vehicle simulation computer 
program. These include recognizing lightweight thermoplastic materials, 
automatic tire inflation systems, advanced cruise control systems, 
workday idle reduction systems, and axle configurations that decrease 
the number of drive axles. We are seeking comment on recognizing 
additional technologies such as high efficiency glass and low global 
warming potential air conditioning refrigerants as post-process 
adjustments to the simulation results.
    To better reflect real-world operation, we are also proposing to 
revise the vehicle simulation computer program's urban (55 mph) and 
rural (65 mph) highway duty cycles to include changes in road grade. We 
are seeking comment on whether or not these duty cycles should also 
simulate driver behavior in response to varying traffic patterns. We 
are proposing a new duty cycle to capture the performance of 
technologies that reduce the amount of time a vehicle's engine is at 
idle during a workday when the vehicle is not moving. And to better 
recognize that vocational vehicle powertrains are configured for 
particular applications, we are proposing to further subdivide the 
vocational chassis category into three different vehicle speed 
categories. This is in addition to the Phase 1 subdivision by three 
weight categories. The result is nine proposed vocational vehicle 
subcategories for Phase 2. The agencies are also proposing to subdivide 
the highest weight class of tractors into two separate categories to 
recognize the unique configurations and technology applicability to 
``heavy-haul'' tractors.
    Even though we are proposing to include engine test results as 
inputs into the vehicle simulation computer model, we are also 
proposing to continue the Phase 1 separate engine standard regulatory 
structure by proposing separate engine fuel consumption and 
CO2 standards for engines installed in tractors and 
vocational chassis. For these separate engine standards, we are 
proposing to continue to use the Phase 1 engine dynamometer test 
procedure, which was adapted substantially from EPA's existing heavy-
duty engine emissions test procedure. However, we are proposing to 
modify the weighting factors of the tractor engine's 13-point steady-
state duty cycle to better reflect real-world engine operation and to 
reflect the trend toward operating engines at lower engine speeds 
during tractor cruise speed operation. Further details on the proposed 
Phase 2 separate engine standards are provided below in Section II. D. 
In today's action EPA is proposing to continue the separate engine cap 
standards for methane (CH4) and nitrous oxide 
(N2O) emissions.
(1) Phase 1 Vehicle Simulation Computer Program (GEM)
    For Phase 1 EPA developed a vehicle simulation computer program 
called, ``Greenhouse gas Emissions Model'' or ``GEM.'' GEM was created 
for Phase 1 for the exclusive purpose of certifying tractors and 
vocational vehicle chassis. GEM is similar in concept to a number of 
other commercially available vehicle simulation computer programs. See 
76 FR 57116, 57146, and 57156-57157. However, GEM is also unique in a 
number of ways.
    Similar to other vehicle simulation computer programs, GEM combines 
various vehicle inputs with known physical laws and justified 
assumptions to predict vehicle performance for a given period of 
vehicle operation. For Phase 1 GEM's vehicle inputs include vehicle 
aerodynamics information (for tractors), tire rolling resistance, and 
whether or not a vehicle is equipped with lightweight materials, a 
tamper-proof speed limiter, or tamper-proof idle reduction 
technologies. Other vehicle and engine characteristics were fixed as 
defaults that cannot be altered by the user. These defaults included 
tabulated data of engine fuel rate as a function of engine speed and 
torque (i.e. ``engine fuel maps''), transmissions, axle ratios, and 
vehicle payloads. For tractors, Phase 1 GEM models the vehicle pulling 
a standard trailer. For vocational vehicles, Phase 1 GEM includes a 
fixed aerodynamic drag coefficient and vehicle frontal area.
    GEM uses the same physical principles as many other existing 
vehicle simulation models to derive governing equations which describe 
driveline components, engine, and vehicle. These equations are then 
integrated in time to calculate transient speed and torque. Some of the 
justified assumptions in GEM include average energy losses due to 
friction between moving parts of a vehicle's powertrain; the logical 
behavior of an average driver shifting from one transmission gear to 
the next; ad speed limit assumptions such as 55 miles per hour for 
urban highway driving and 65 miles per hour for rural interstate 
highway driving. The sequence of the GEM vehicle simulation can be 
visualized by imagining a human driver initially sitting in a parked 
running tractor or vocational vehicle. The driver then proceeds to 
drive the vehicle over a prescribed route that

[[Page 40177]]

includes three distinct patterns of driving: Stop-and-go city driving, 
urban highway driving, and rural interstate highway driving. The driver 
then exits the highway and brings the vehicle to a stop. This concludes 
the vehicle simulation.
    Over each of the three driving patterns or ``duty cycles,'' GEM 
simulates the driver's behavior of pressing the accelerator, coasting, 
or applying the brakes. GEM also simulates how the engine operates as 
the gears in the vehicle's transmission are shifted and how the 
vehicle's weight, aerodynamics, and tires resist the forward motion of 
the vehicle. GEM combines the driver behavior over the duty cycles with 
the various vehicle inputs and other assumptions to determine how much 
fuel must be consumed to move the vehicle forward at each point during 
the simulation. For each of the three duty cycles, GEM totals the 
amount of fuel consumed and then divides that amount by the product of 
the miles travelled and tons of payload carried. The tons of payload 
carried are specified by the agencies for each vehicle type and weight 
class. For each regulatory subcategory of tractor and vocational 
vehicle (e.g., sleeper cab tractor, day cab tractor, small vocational 
vehicle, large vocational vehicle, etc.), GEM applies prescribed 
weighting factors to each of the three duty cycles to represent the 
fraction of city, urban highway, and rural highway driving that would 
be typical of each subcategory. After completing all the cycles, GEM 
outputs a single composite result for the vehicle, expressed as both 
fuel consumed in gallon per 1,000 ton-miles (for NHTSA standards) and 
an equivalent amount of CO2 emitted in grams per ton-mile 
(for EPA standards). These are the vehicle's GEM results that are used 
along with other information to demonstrate the vehicle complies with 
the applicable standards. This other information includes the annual 
sales volume of the vehicle (family) simulated in GEM, plus information 
on emissions credits that may be generated or used as part of that 
vehicle family's certification.
    While GEM is similar to other vehicle simulation computer programs, 
GEM is also unique in a number of ways. First, GEM was designed 
exclusively for regulated entities to certify tractor and vocational 
vehicle chassis to the agencies' respective fuel consumption and 
CO2 emissions standards. For GEM to be effective for this 
purpose, the inputs to GEM include only information related to vehicle 
components and attributes that significantly impact vehicle fuel 
efficiency and CO2 emissions. For example, these include 
vehicle aerodynamics, tire rolling resistance, and whether or not a 
vehicle is equipped with lightweight materials, a tamper-proof speed 
limiter, or tamper-proof idle reduction technologies. On the other 
hand, other attributes such as those related to a vehicle's suspension, 
frame strength, or interior features are not included, where these 
might be included in other commercially available vehicle simulation 
programs for other purposes. Furthermore, the simulated driver behavior 
and the duty cycles cannot be changed in the GEM executable program. 
This helps to ensure that all vehicles are simulated and certified in 
the same way, but this does preclude GEM from being of much use as a 
research tool for exploring the effects of driver behavior and of 
different duty cycles.
    To allow for public comment, GEM is available free of charge for 
unlimited use, and the GEM source code is open source. That is, the 
programming source code of GEM is freely available upon request for 
anyone to examine, manipulate, and generally use without restriction. 
In contrast commercially available vehicle simulation programs are 
generally not free and open source. Additional details of GEM are 
included in Chapter 4 of the RIA.
    As part of Phase 1, the agencies conducted a peer review of GEM 
version 1.0, which was the version released for the Phase 1 
proposal.81 82 In response to this peer review and comments 
from stakeholders, EPA has made changes to GEM. The current version of 
GEM is v2.0.1, which is the version applicable for the Phase 1 
standards.\83\
---------------------------------------------------------------------------

    \81\ See 76 FR 57146-57147.
    \82\ U.S. Environmental Protection Agency. ``Peer Review of the 
Greenhouse Gas Emissions Model (GEM) and EPA's Response to 
Comments.'' EPA-420-R-11-007. Last access on November 24, 2014 at 
http://www.epa.gov/otaq/climate/documents/420r11007.pdf.
    \83\ See EPA's Web site at http://www.epa.gov/otaq/climate/gem.htm for the Phase 1 GEM revision dated May 2013, made to 
accommodate a revision to 49 CFR 535.6(b)(3).
---------------------------------------------------------------------------

(2) Phase 1 Engine Standards and Engine Test Procedure
    For Phase 1 the agencies set separate engine fuel consumption and 
CO2 standards for engines installed in tractors and 
vocational vehicle chassis. EPA also set separate engine cap standards 
for methane (CH4) and nitrous oxide (N2O) 
emissions. These Phase 1 engine standards are specified in terms of 
brake-specific (g/hp-hr) fuel, CO2, CH4 and 
N2O emissions limits. For these separate engine standards, 
the agencies adopted an engine dynamometer test procedure, which was 
built substantially from EPA's existing heavy-duty engine emissions 
test procedure. Since the test procedure already specified how to 
measure fuel consumption, CO2 and CH4, few 
changes were needed to employ the test procedure for purposes of the 
Phase 1 standards. For Phase 1 the test procedure was modified to 
specify how to measure N2O.
    The duty cycles from EPA's existing heavy-duty emissions test 
procedure were used in a somewhat unique way for Phase 1. In EPA's non-
GHG engine emissions standards, heavy-duty engines must meet brake-
specific standards for emissions of total oxides of nitrogen 
(NOX), particulate mass (PM), non-methane hydrocarbon 
(NMHC), and carbon monoxide (CO). These standards must be met by all 
engines both over a 13-mode steady-state duty cycle called the 
``Supplemental Emissions Test'' (SET) and over a composite of a cold-
start and a hot-start transient duty cycle called the ``Federal Test 
Procedure'' (FTP). In contrast, for Phase 1 the agencies require that 
engines specifically installed in tractors meet fuel efficiency and 
CO2 standards over only the SET but not the FTP. This 
requirement was intended to reflect that tractor engines typically 
operate near steady-state conditions versus transient conditions. See 
76 FR 57159. The agencies adopted the converse for engines installed in 
vocational vehicles. That is, these engines must meet fuel efficiency 
and CO2 standards over only the hot-start FTP but not the 
SET. This requirement was intended to reflect that vocational vehicle 
engines typically operate under transient conditions versus steady-
state conditions (76 FR 57178). For both tractor and vocational vehicle 
engines in Phase 1, EPA set CH4 and N2O emissions 
cap standards over the cold-start and hot-start FTP only and not over 
the SET duty cycle. See Section II. D. for details on how we propose to 
modify the engine test procedure for Phase 2.

B. Phase 2 Proposed Regulatory Structure

    For Phase 2, the agencies are proposing to modify the regulatory 
structure used for Phase 1. Note that we are not proposing to apply the 
new Phase 2 regulatory structure for compliance with the Phase 1 
standards. The structure used to demonstrate compliance with the Phase 
1 standards will remain as finalized in the Phase 1 regulation. The 
modifications we are proposing are consistent with the agencies' Phase 
1 commitments to consider a range of regulatory approaches during the 
development of

[[Page 40178]]

future regulatory efforts (76 FR 57133), especially for vehicles not 
already subject to full vehicle chassis dynamometer testing. For 
example, we committed to consider a more sophisticated approach to 
vehicle testing to more completely capture the complex interactions 
within the total vehicle, including the engine and powertrain 
performance. We also intended to consider the potential for full 
vehicle certification of complete tractors and vocational chassis using 
a chassis dynamometer test procedure. We also considered chassis 
dynamometer testing of complete tractors and vocational chassis as a 
complementary approach for validating a more complex vehicle simulation 
approach. We also committed to consider the potential for a regulatory 
program for some of the trailers hauled by tractors. After considering 
these various approaches, the agencies are proposing a structure in 
which regulated tractor and vocational chassis manufacturers would 
additionally enter engine and powertrain-related inputs into GEM, which 
was not allowed in Phase 1.
    For trailer manufacturers, which would be subject to first-time 
standards under the proposal, we are also proposing GEM-based 
certification. However, we are proposing a simplified structure that 
would allow certification without the manufacturers actually running 
GEM. More specifically, the agencies have developed a simple equation 
that uses the same trailer inputs as GEM to represent the emission 
impacts of aerodynamic improvements, tire improvements, and weight 
reduction. As described in Chapter 2.10.6 of the draft RIA, these 
equations have nearly perfect correlation with GEM so that they can be 
used instead of GEM without impacting stringency.
    We are proposing both required and optional test procedures to 
provide these additional GEM inputs. We are also proposing to 
significantly expand the number of technologies recognized in GEM. 
Further, we are proposing to modify the GEM duty cycles and to further 
subdivide the vocational vehicle subcategory to better represent real-
world vehicle operation. In contrast to these changes, we are proposing 
to maintain essentially the same chassis dynamometer test procedure for 
certifying complete heavy-duty pickups and vans.
(1) Other Structures Considered
    To follow-up on the commitment to consider other approaches, the 
agencies spent significant time and resources in evaluating six 
different options for demonstrating compliance with the proposed Phase 
2 standards. These six options include full vehicle chassis dynamometer 
testing, full vehicle simulation, and vehicle simulation in combination 
with powertrain testing, engine testing, engine electronic controller 
and/or transmission electronic controller testing. The agencies 
evaluated these options in terms of the capital investment required of 
regulated manufacturers to conduct the testing and/or simulation, the 
cost per test, the accuracy of the simulation, and the challenges of 
validating the results. Other considerations included the 
representativeness to the real world behavior, maintaining existing 
Phase 1 certification approaches that are known to work well, enhancing 
the Phase 1 approaches that could use improvements, the alignment of 
test procedures for determining GHG and non-GHG emissions compliance, 
and the potential to circumvent the intent of the test procedures.
    Chassis dynamometer testing is used extensively in the development 
and certification of light-duty vehicles. It also is used in Phase 1 
for complete Class 2b/3 pickups and vans, as well as for certain 
incomplete vehicles (at the manufacturer's option). The agencies 
considered chassis dynamometer testing more broadly as a heavy-duty 
fuel efficiency and GHG certification option because chassis 
dynamometer testing has the ability to evaluate a vehicle's performance 
in a manner that most closely resembles the vehicle's in-use 
performance. Nearly all of the fuel efficiency technologies can be 
evaluated on a chassis dynamometer, including the vehicle systems' 
interactions that depend on the behavior of the engine, transmission, 
and other vehicle electronic controllers. One challenge associated with 
application of wide-spread heavy-duty chassis testing is the small 
number of heavy-duty chassis test sites that are available in North 
America. As discussed in draft RIA Chapter 3, the agencies were only 
able to locate 11 heavy-duty chassis test sites. However, we have seen 
an increased interest in building new sites since issuing the Phase 1 
Final Rule. For example, EPA is currently building a heavy-duty chassis 
dynamometer with the ability to test up to 80,000 pound vehicles at the 
National Vehicle and Fuel Emissions Laboratory in Ann Arbor, Michigan.
    Nevertheless, the agencies continue to be concerned about proposing 
a chassis test procedure for certifying tractors or vocational chassis 
due to the initial cost of a new test facility and the large number of 
heavy duty tractor and vocational chassis variants that could require 
testing. We have also concluded that for heavy-duty tractors and 
vocational chassis, there can be increased test-to-test variability 
under chassis dynamometer test conditions. First, the agencies 
recognize that such testing requires expensive, specialized equipment 
that is not widely available. The agencies estimate that it would vary 
from about $1.3 to $4.0 million per new test site depending on existing 
facilities.\84\ In addition, the large number of heavy-duty vehicle 
configurations would require significant amounts of testing to cover 
the sector. For example, for Phase 1 tractor manufacturers typically 
certified several thousand variants of one single tractor model. 
Finally, EPA's evaluation of heavy-duty chassis dynamometer testing has 
shown that the variation of chassis test results is greater than light-
duty testing, up to 3 percent worse, based on our sponsored testing at 
Southwest Research Institute.\85\ Although the agencies are not 
proposing chassis dynamometer certification of tractors and vocational 
chassis, we believe such an approach could be appropriate in the future 
for some heavy duty vehicles if more test facilities become available 
and if the agencies are able to address the large number of vehicle 
variants that might require testing. We request comment on whether or 
not a chassis dynamometer test procedure should be required in lieu of 
the vehicle simulation approach we are proposing. Note, as discussed in 
Section II. C. (4) (b) that we are also proposing a modest complete 
tractor heavy-duty chassis dynamometer test program only for monitoring 
complete tractor fuel efficiency trends over the implementation 
timeframe of the Phase 1 and proposed Phase 2 standards.
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    \84\ 03-19034 TASK 2 Report-Paper 03-Class8_hil_DRAFT, September 
30, 2013.
    \85\ GEM Validation, Technical Research Workshop, San Antonio, 
December 10-11, 2014.
---------------------------------------------------------------------------

    Another option considered for certification involves testing a 
vehicle's powertrain in a modified engine dynamometer test facility. In 
this case the engine and transmission are installed in a laboratory 
test facility and a dynamometer is connected to the output shaft of the 
transmission. GEM or an equivalent vehicle simulation computer program 
is then used to control the dynamometer to simulate vehicle speeds and 
loads. The step-by-step test procedure considered for this option was 
initially developed as an option for hybrid powertrain testing for 
Phase 1. A key advantage of the powertrain test approach is that it

[[Page 40179]]

directly measures the effectiveness of the engine, the transmission, 
and the integration of the two. Engines and transmissions are 
particularly challenging to simulate within a computer program like GEM 
because engines and transmissions installed in vehicles today are 
actively and interactively controlled by their own sophisticated 
electronic controls. These controls already contain essentially their 
own vehicle simulation programs that GEM would then have to otherwise 
simulate.
    We believe that the capital investment impact for powertrain 
testing on manufacturers could be manageable for those that already 
have heavy-duty engine dynamometer test cells. We have found that in 
general medium-duty powertrains can be tested in heavy-duty engine test 
cells. EPA has successfully completed such a test facility conversion 
at the National Vehicle and Fuel Emissions Laboratory in Ann Arbor, 
Michigan. Southwest Research Institute (SwRI) in San Antonio, Texas has 
completed a similar test cell conversion. Oak Ridge National Laboratory 
in Oak Ridge, Tennessee recently completed construction of a new and 
specialized heavy heavy-duty powertrain dynamometer facility. EPA also 
contracted SwRI to evaluate North America's current capabilities for 
powertrain testing in the heavy-duty sector and the cost of installing 
a new powertrain cell that would meet agency requirements.\86\ Results 
indicated that one supplier currently has this capability. We estimate 
that the upgrade costs to an existing engine test facility are on the 
order of $1.2 million, and a new test facility in an existing building 
are on the order of $1.9 million. We also estimate that current 
powertrain test cells that could be upgraded to measure CO2 
emissions would cost approximately $600,000. For manufacturers or 
suppliers wishing to contract out such testing, SwRI estimated that a 
cost of $150,000 would provide about one month of powertrain testing 
services. Once a powertrain test cell is fully operational, we estimate 
that for a nominal powertrain family (i.e. one engine family tested 
with one transmission family), the cost for powertrain installation, 
testing, and data analysis would be $68,972.
---------------------------------------------------------------------------

    \86\ 03-19034 TASK 2 Report-Paper 03-Class8_hil_DRAFT, September 
30, 2013.
---------------------------------------------------------------------------

    Since the Phase 1 Final Rule, the agencies and other stakeholders 
have completed significant new work toward refining the powertrain test 
procedure itself. The proposed regulations provide details of the 
refined powertrain test procedure. See 40 CFR 1037.550.
    Furthermore, the agencies have worked with key transmission 
suppliers to develop an approach to define transmission families. 
Coupled with the agencies existing definitions of engine families (40 
CFR 1036.230 and 1037.230), we are proposing an approach to define a 
powertrain family in 40 CFR 1037.231. We request comment on what key 
attributes should be considered when defining a transmission family.
    We believe that a combination of a robust powertrain family 
definition, a refined powertrain test procedure and a refined GEM could 
become an optimal certification path that leverages the accuracy of 
powertrain testing along with the versatility of GEM, which alleviates 
the need to test a large number of vehicle or powertrain variants. To 
balance the potential advantages of this approach with the fact that it 
has never been used for vehicle certification in the past, we are 
proposing to allow this approach as an optional certification path, as 
described in Section II.B.(2)(b). To be clear, we are not proposing to 
require powertrain testing at this time, but because this testing would 
recognize additional technologies that are not recognized directly in 
GEM (even as proposed to be amended), we are factoring its use into our 
stringency considerations for vocational chassis. We request comment on 
whether the agencies should consider requiring powertrain testing more 
broadly.
    Another regulatory structure option considered was engine-only 
testing over the GEM duty cycles over a range of simulated vehicle 
configurations. This approach would use GEM to generate engine duty 
cycles by simulating a range of transmissions and other vehicle 
variations. These engine duty cycles then would be programmed into a 
separate controller of a dynamometer connected to an engine's output 
shaft. Unlike the chassis dynamometer or powertrain dynamometer 
approaches, which could have significant test facility construction or 
modification costs, this approach has little capital investment impact 
on manufacturers because the majority already have engine test 
facilities to both develop engines and to certify engines to meet both 
the non-GHG standards and the Phase 1 fuel efficiency and GHG 
standards. The agencies also have been investigating this approach as 
an alternative way to generate data that could be used to represent an 
engine in GEM. Because this approach captures engine performance under 
transient conditions, this approach could be an improvement over our 
proposed Phase 2 approach of representing an engine in GEM with only 
steady-state operating data. Details of this alternative are described 
in draft RIA. Because this approach is new and has never been used for 
vehicle development or certification, we are not proposing requiring 
its use as part of the Phase 2 certification process. However, we 
encourage others to investigate this new approach in detail, and we 
request comment on whether or not the agencies should replace our 
proposed steady-state operation representation of the engine in GEM 
with this alternative approach.
    Additional certification options considered included simulating the 
engine, transmission, and vehicle using a computer program while having 
the actual transmission electronic controller connected to the computer 
running the vehicle simulation program. The output of the simulation 
would be an engine cycle that would be used to test the engine in an 
engine test facility. Just as in the engine-only test procedure, this 
procedure would not require significant capital investment in new test 
facilities. An additional benefit of this approach would be that the 
actual transmission controller would be determining the transmission 
gear shift points during the test, without a transmission manufacturer 
having to reveal their proprietary transmission control logic. This 
approach comes with some technical challenges, however. The model would 
have to become more complex and tailored to each transmission and 
controller to make sure that the controller would operate properly when 
it is connected to a computer instead of a transmission. Some examples 
of the transmission specific requirements would be simulating all the 
Controller Area Network (CAN) communication to and from the 
transmission controller and the specific sensor responses both through 
simulation and hardware. The vehicle manufacturer would have to be 
responsible for connecting the transmission controller to the computer, 
which would require a detailed verification process to ensure it is 
operating properly. Determining full compliance with this test 
procedure would be a significant challenge for the regulatory agencies 
because the agencies would have to be able to replicate each of the 
manufacturer's unique interfaces between the transmission controller 
and computer running GEM.
    Finally, the agencies considered full vehicle simulation plus 
separate engine standards, which is the proposed

[[Page 40180]]

approach for Phase 2. These are discussed in more detail in the 
following sections.
(2) Proposed Regulatory Structure
    Under the proposed structure, tractor and vocational chassis 
manufacturers would be required to provide engine, transmission, drive 
axle(s) and tire radius inputs into GEM. For Phase 1, GEM used default 
values for all of these, which limited the types of technologies that 
could be recognized by GEM to show compliance with the standards. We 
are proposing to significantly expand GEM to account for a wider range 
of technological improvements that would otherwise need to be 
recognized through some off-cycle crediting approach. These include 
improvements to the driver controller (i.e., the simulation of the 
driver), engines, transmissions, and axles. Additional technologies 
that would now be recognized in GEM also include lightweight 
thermoplastic materials, automatic tire inflation systems, advanced 
cruise control systems, engine stop-start idle reduction systems, and 
axle configurations that decrease the number of drive axles. The 
agencies are also proposing to maintain separate engine standards. As 
described below, we see advantages to having both engine-based and 
vehicle-based standards. Moreover, the advantages described here for 
full vehicle simulation do not necessarily correspond to disadvantages 
for engine testing or vice versa.
(a) Advantages of Full Vehicle Simulation
    The agencies' primary purpose in developing fuel efficiency and GHG 
emissions standards is to increase the use of vehicle technologies that 
improve fuel efficiency and decrease GHG emissions. Under the Phase 1 
tractor and vocational chassis standards, there is no regulatory 
incentive for manufacturers to adopt new engine, transmission or axle 
technologies because GEM was not configured to recognize these 
technologies uniquely. By recognizing such technologies in GEM under 
Phase 2, the agencies would be creating a regulatory incentive to 
improve engine, transmission, and axle technologies to improve fuel 
efficiency and decrease GHG emissions. In its 2014 report, NAS also 
recognized the benefits of full vehicle simulation and recommended that 
Phase 2 incorporate such an approach.
    We anticipate that the proposed Phase 2 approach would create three 
new specific regulatory incentives. First, vehicle manufacturers would 
have an incentive to use the most efficient engines. Since GEM would no 
longer use the agency default engine in simulation manufacturers would 
have their own more efficient engines recognized in GEM. Under Phase 1, 
engine manufacturers have a regulatory incentive to design efficient 
engines, but vehicle manufacturers do not have a similar regulatory 
incentive to use efficient engines in their vehicles. Second, the 
proposed approach would create incentives for both engine and vehicle 
manufacturers to design engines and vehicles to work together to ensure 
that engines actually operate as much as possible near their most 
efficient points. This is because Phase 2 GEM would allow the vehicle 
manufactures to use specific transmission, axle, and tire 
characteristics as inputs, thus having the ability to directly 
recognize many powertrain integration benefits, such as downspeeding, 
and different transmission architectures and technologies, such as 
automated manual transmissions, automatic transmissions,, and different 
numbers of transmission gears, transmission gear ratios, axle ratios 
and tire revolutions per mile. No matter how well designed, all engines 
have speed and load operation points with differing fuel efficiency and 
GHG emissions. The speed and load point with the best fuel efficiency 
(i.e., peak thermal efficiency) is commonly known as the engine's 
``sweet spot''. The more frequently an engine operates near its sweet 
spot, the better the vehicle's fuel efficiency will be. In Phase 1, a 
vehicle manufacturer receives no regulatory credit for designing its 
vehicle to operate closer to the sweet spot because Phase 1 GEM does 
not model the actual engine, transmission, axle, or tire revolutions 
per mile. Third, the proposed approach would recognize improvements to 
the overall efficiency of the drivetrain including the axle. The 
proposed version of GEM would recognize the benefits of different axle 
technologies including axle lubricants, and reducing axle losses such 
as by enabling three-axle vehicles to deliver power to only one rear 
axle through the proposed post-simulation adjustment approach (see 
Chapter 4.5 of the Draft RIA).
    In addition to providing regulatory incentives to use more fuel 
efficient technologies, expanding GEM to recognize engine and other 
powertrain component improvements would also provide important 
flexibility to vehicle manufacturers. The flexibility to effectively 
trade engine and other component improvements against other vehicle 
improvements would allow vehicle manufacturers to better optimize their 
vehicles to achieve the lowest cost for specific customers. Vehicle 
manufacturers could use this flexibility to reduce overall compliance 
costs and/or address special applications where certain vehicle 
technologies are not practical. The agencies considered in Phase 1 
allowing the exchange of emission certification credits generated 
relative to the separate brake-specific (g/hp-hr) engine standards and 
credits generated relative to the vehicle standards (g/ton-mile). 
However, we did not allow this in Phase 1 due in part to concerns about 
the equivalency of credits generated relative to different standards, 
with different units of measure and different test procedures. The 
proposed approach for Phase 2 would eliminate these concerns because 
engine and other vehicle component improvements would be evaluated 
relative to the same vehicle standard in GEM. This also means that 
under the proposed Phase 2 approach there is no need to consider 
allowing emissions credit trading between engine-generated and vehicle-
generated credits because vehicle manufacturers are directly credited 
by the combination of engine and vehicle technologies they choose to 
install in each vehicle. Therefore, this approach eliminates one of the 
concerns about continuing separate engine standards, which was that a 
separate engine standard and a full vehicle standard were somehow 
mutually exclusive. That is not the case. In fact, in the next section 
we describe how we propose to continue the separate engine standard 
along with recognizing engine performance at the vehicle level. The 
agencies acknowledge that maintaining a separate engine standard would 
limit flexibility in cases where a vehicle manufacturer wanted to use 
less efficient engines and make up for them using more efficient 
vehicle technologies. However, as described below, we see important 
advantages to maintaining a separate engine standard, and we believe 
they more than justify the reduced flexibility.
    There could be disadvantages to the proposed approach, however. As 
is discussed in Section II.B.(2)(b), some of the disadvantages can be 
addressed by maintaining separate engine standards, which we are 
proposing to do. We request comment on other disadvantages such as 
those discussed below.
    One disadvantage of the proposed approach is that it would increase 
complexity for the vehicle standards. For example, vehicle 
manufacturers would be required to conduct additional engine tests and 
track additional GEM

[[Page 40181]]

inputs for compliance purposes. However, we believe that most of the 
burden associated with this increased complexity would be an infrequent 
burden of engine testing and updating information systems to track 
these inputs.
    Because GEM measures performance over specific duty cycles intended 
to represent average operation of vehicles in-use, the proposed 
approach might also create an incentive to optimize powertrains and 
drivetrains for the best GEM performance rather than the best in-use 
performance for a particular application. This is always a concern when 
selecting duty cycles for certification. There will always be 
instances, however infrequent, where specific vehicle applications will 
operate differently than the duty cycles used for certification. The 
question is would these differences force manufacturers to optimize 
vehicles to the certification duty cycles in a way that decreases fuel 
efficiency and increases GHG emissions in-use? We believe that the 
certification duty cycles would not prevent manufacturers from properly 
optimizing vehicles for customer fuel efficiency. First, the impact of 
the certification duty cycles would be relatively small because they 
affect only a small fraction of all vehicle technologies. Second, the 
emission averaging and fleet average provisions mean that the proposed 
regulations would not require all vehicles to meet the standards. 
Vehicles exceeding a standard over the duty cycles because they are 
optimized for different in-use operation can be offset by other 
vehicles that perform better over the certification duty cycles. Third, 
vehicle manufacturers would also have the ability to lower such a 
vehicle's measured GHG emissions by adding technology that would 
improve fuel efficiency both over the certification duty cycles and in-
use. The proposed standards are not intended to be at a stringency 
where manufacturers would be expected to apply all technologies to all 
vehicles. Thus, there should be technologies available to add to 
vehicle configurations that initially fail to meet the Phase 2 proposed 
standards. Fourth, we are proposing further sub-categorization of the 
vocational vehicle segment, tripling the number of subcategories within 
this segment from 3 to 9. These 9 subcategories would divide each of 
the 3 Phase 1 weight categories into 3 additional vehicle speed 
categories. Each of the 3 speed categories would have unique duty cycle 
weighting factors to recognize that different vocational chassis are 
configured for different vehicle speed applications. Furthermore, we 
are proposing 9 unique standards for each of the subcategories. This 
further subdivision better recognizes technologies' performance under 
the conditions for which the vocational chassis was configured to 
operate. This further decreases the potential of the certification duty 
cycles to encourage manufacturers to configure vocational chassis 
differently than the optimum configuration for specific customers' 
applications. Finally, as required by Section 202 (a) (1) and 202 (d) 
of the CAA, EPA is proposing specific GHG standards which would have to 
be met in-use.
    One disadvantage of our proposed full vehicle simulation approach 
is the potential requirement for engine manufacturers to disclose 
otherwise proprietary information to vehicle manufacturers who install 
their engines. Under the proposed approach, vehicle manufacturers would 
need to know details about engine performance long before production, 
both for compliance planning purposes, as well as for the actual 
submission of applications for certification. Moreover, vehicle 
manufacturers would need to know details about the engine's performance 
that are generally not publicly available--specifically the detailed 
fuel consumption of an engine over many steady-state operating points. 
We request comment on whether or not such information could be used to 
``reverse engineer'' intellectual property related to the proprietary 
design of engines, and what steps the agencies could take to address 
this.
    The agencies also generally request comment on the advantages and 
disadvantages of the proposed structure that would require vehicle 
manufacturers to provide additional inputs into GEM to represent the 
engine, transmission, drive axle(s), and loaded tire radius.
(b) Advantages of Separate Engine Standards
    For engines installed in tractors and vocational vehicle chassis, 
we are proposing to maintain separate engine standards for fuel 
consumption and GHG emissions in Phase 2 for both SI and CI engines. 
Moreover, we are proposing new more stringent engine standards for CI 
engines. While the vehicle standards alone are intended to provide 
sufficient incentive for improvements in engine efficiency, we continue 
to see important advantages to maintaining separate engine standards 
for both SI and CI engines. The agencies believe the advantages 
described below are critical to fully achieve the goals of the NHTSA 
and EPA standards.
    First, EPA has a robust compliance program based on engine testing. 
For the Phase 1 standards, we applied the existing criteria pollutant 
compliance program to ensure that engine efficiency in actual use 
reflected the improvements manufacturers claimed during certification. 
With engine-based standards, it is straightforward to hold engine 
manufacturers accountable by testing in-use engines. If the engines 
exceed the standards, they can be required to correct the problem or 
perform other remedial actions. Without separate engine standards in 
Phase 2, addressing in-use compliance becomes more subjective. Having 
clearly defined compliance responsibilities is important to both the 
agencies and to the market.
    Second, engine standards for CO2 and fuel efficiency 
force engine manufacturers to optimize engines for both fuel efficiency 
and control of non-CO2 emissions at the same engine 
operating points. This is of special concern for NOX 
emissions, given the strong counter-dependency between engine-out 
NOX emissions and fuel consumption. By requiring engine 
manufacturers to comply with both NOX and CO2 
standards using the same test procedures, the agencies ensure that 
manufacturers include technologies that can be optimized for both 
rather than alternate calibrations that would trade NOX 
emissions against fuel consumption depending how the engine or vehicle 
is tested. In the past, when there was no CO2 engine 
standard and no steady-state NOX standard, some 
manufacturers chose this dual calibration approach instead of investing 
in technology that would allow them to simultaneously reduce both 
CO2 and NOX.
    Third, engine fuel consumption can vary significantly between 
transient operation and steady-state operation, and we are proposing 
only steady-state engine operating data as the required engine input 
into GEM for both tractor and vocational chassis certification. Because 
vocational vehicles can spend significant operation under transient 
engine operation, the separate engine standard for engines installed in 
vocational vehicles is a transient test. Therefore, the separate engine 
standard for vocational engines provides the only measure of engine 
fuel consumption and CO2 emissions under transient 
conditions. Without a transient engine test we would not be able to 
ensure control of fuel consumption and CO2 emissions under 
transient engine conditions.

[[Page 40182]]

    It is worth noting that these first three advantages are also 
beneficial for the marketplace. In these respects, the separate engine 
standards allow each manufacturer to be confident that its competitors 
are playing by the same rules. The agencies believe that the absence of 
a separate engine standard would leave open the possibility that a 
manufacturer might choose to cut corners with respect to in-use 
compliance margins, the NOX-CO2 tradeoff, or 
transient controls. Concerns that competitors might take advantage of 
this can put a manufacturer in a difficult situation. On the other hand 
knowing that the agencies are ensuring all manufacturers are complying 
fully can eliminate these concerns.
    Finally, the existence of meaningful separate engine standards 
allows the agencies to exempt certain vehicles from some or all of the 
vehicle standards and requirements without forgoing the engine 
improvements. A good example of this is the off-road vehicle exemption 
in 40 CFR 1037.631 and 49 CFR 535.3, which exempts vehicles ``intended 
to be used extensively in off-road environments'' from the vehicle 
requirements. The engines used in such vehicles must still meet the 
engine standards of 40 CFR 1036.108 and 49 CFR 535.5(d). The agencies 
see no reason why efficient engines cannot be used in such vehicles. 
However, without separate engine standards, there would be no way to 
require them to be efficient.
    In the past there has been some confusion about the Phase 1 
separate engine standards somehow preventing the recognition of engine-
vehicle optimization that vehicle manufacturers perform to minimize a 
vehicle's overall fuel consumption. It was not the existence of 
separate engine standards that prevented recognition of this 
optimization. Rather it was that the agencies did not allow 
manufacturers to enter inputs into GEM that characterized unique engine 
performance. For Phase 2 we are proposing to require that manufacturers 
input such data because we intend for GEM to recognize this engine-
vehicle optimization. The continuation of separate engine standards in 
Phase 2 does not undermine in any way the recognition of this 
optimization in GEM.
    The agencies request comment on the advantages and disadvantages of 
the proposal to maintain separate engine standards and to increase the 
stringency of the CI engine standards. We would also welcome suggested 
alternative approaches that would achieve the same goals. It is 
important to emphasize that the agencies see the advantages of separate 
engine standards as fundamental to the success of the program and do 
not expect to adopt alternative approaches that fall short of these 
goals.
    Note that commenters opposing separate engine standards should also 
be careful distinguish between concerns related to the stringency of 
the proposed engine standards, from concerns inherent to any separate 
engine standards whatsoever. When meeting with manufacturers prior to 
this proposal, the agencies heard many concerns about the potential 
problems with separate engines standards that were actually concerns 
about separate engine standards that are too stringent. However, we see 
these as two different issues. The agencies do recognize that setting 
engine standards at a high stringency could increase the cost to comply 
with the vehicle standard, if lower-cost vehicle technologies are 
available. Additionally, the agencies recognize that setting engine 
standards at a high stringency may promote the use of large-
displacement engines, which have inherent heat transfer and efficiency 
advantages over smaller displacement engines over the engine test 
cycles, though a smaller engine may be more efficient for a given 
vehicle application. Thus we encourage commenters supporting the 
separate engine standards to address the possibility of unintended 
consequences such as these.

C. Proposed Vehicle Simulation Model--Phase 2 GEM 87
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    \87\ The specific version of GEM used to develop the proposed 
standards, and which we propose to use for compliance purposes is 
also known as GEM 3.0.
---------------------------------------------------------------------------

    For tractors and vocational vehicle chassis, the agencies propose 
that manufacturers would be required to meet vehicle-based standards, 
and certification to these standards would be facilitated by the 
required use of the vehicle simulation computer program called, 
``Greenhouse gas Emissions Model'' or ``GEM.'' GEM was created for 
Phase 1 for the exclusive purpose of certifying tractors and vocational 
chassis. The agencies are proposing to modify GEM and to require 
vehicle manufacturers to provide additional inputs into GEM to 
represent the engine, transmission, drive axle(s), and loaded tire 
radius. For Phase 1, GEM used agency default values for all of these 
parameters. Under the proposed approach for Phase 2, vehicle 
manufacturers would be able to use these technologies, plus additional 
technologies to demonstrate compliance with the applicable standards. 
The additional technologies include lightweight thermoplastic 
materials, automatic tire inflation systems, advanced cruise control 
systems, engine stop-start idle reduction systems, and axle 
configurations that decrease the number of drive axles to comply with 
the standards.
(1) Description of the Proposed Modifications to GEM
    As explained above, GEM is a computer program that was originally 
developed by EPA specifically for manufacturers to use to certify to 
the Phase 1 tractor and vocational chassis standards. GEM 
mathematically combines the results of vehicle component test 
procedures with other vehicle attributes to determine a vehicle's 
certified levels of fuel consumption and CO2 emissions. For 
Phase 1 the required inputs to GEM include vehicle aerodynamics 
information, tire rolling resistance, and whether or not a vehicle is 
equipped with certain lightweight high-strength steel or aluminum 
components, a tamper-proof speed limiter, or tamper-proof idle 
reduction technologies for tractors. The vocational vehicle inputs to 
GEM for Phase 1 only included tire rolling resistance. For Phase 1 the 
GEM's inputs did not include engine test results or attributes related 
to a vehicle's powertrain; namely, its transmission, drive axle(s), or 
loaded tire radius. Instead, for Phase 1 the agencies specified a 
generic engine and powertrain within GEM, and for Phase 1 these cannot 
be changed in GEM.
    For this proposal GEM has been modified and validated against a set 
of experimental data that represents over 130 unique vehicle variants. 
EPA believes this new version of GEM is an accurate and cost-effective 
alternative to measuring fuel consumption and CO2 over a 
chassis dynamometer test procedure. Some of the key proposed 
modifications would necessitate required and optional vehicle component 
test procedures to generate additional GEM inputs. The results of which 
would provide additional inputs into GEM. These include a new required 
engine test procedure to provide steady-state engine fuel consumption 
and CO2 inputs into GEM. We are also seeking comment on a 
newly developed engine test procedure that also captures transient 
engine performance for use in GEM. We are proposing to require inputs 
that describe the vehicle's transmission type, and its number of gears 
and gear ratios. We are proposing an optional powertrain test procedure 
that would provide inputs to override

[[Page 40183]]

the agencies' simulated engine and transmission in GEM. We are 
proposing to require inputs that describe the vehicle's drive axle(s) 
type (e.g., 6x4 or 6x2) and axle ratio. We are also seeking comment on 
an optional axle efficiency test procedure to override the agencies' 
simulated axle in GEM. We are proposing to significantly expand the 
number of technologies that are recognized in GEM. These include 
recognizing lightweight thermoplastic materials, automatic tire 
inflation systems, advanced cruise control systems, engine stop-start 
idle reduction systems, and axle configurations that decrease the 
number of drive axles. We are seeking comment on recognizing (outside 
of the GEM simulation) additional technologies such as high efficiency 
glass and low global warming potential air conditioning refrigerants. 
To better reflect real-world operation, we are also proposing to revise 
the vehicle simulation computer program's urban and rural highway duty 
cycles to include changes in road grade. We are seeking comment on 
whether or not these duty cycles should also simulate driver behavior 
in response to varying traffic patterns. We are proposing a new duty 
cycle to capture the performance of technologies that reduce the amount 
of time a vehicle's engine is at idle during a workday when the vehicle 
is not moving. And to better recognize that vocational vehicle 
powertrains are configured for particular applications, we are 
proposing to further subdivide the vocational chassis category into 
three different vehicle speed categories, where GEM weights the 
individual duty cycles' results of each of the speed categories 
differently. Section 4.2 of the RIA details all these modifications. 
This section briefly describes some of the key proposed modifications 
to GEM.
(a) Simulating Engines for Vehicle Certification
    Before describing the proposed approach for Phase 2, this section 
first reviews how engines are simulated for vehicle certification in 
Phase 1. GEM for Phase 1 simulates the same generic engine for any 
vehicle in a given regulatory subcategory with a data table of steady-
state engine fuel consumption mass rates (g/s) versus a series of 
steady-state engine output shaft speeds (revolutions per minute, rpm) 
and loads (torque, N-m). This data table is also sometimes called a 
``fuel map'' or an ``engine map'', although the term ``engine map'' can 
mean other kinds of data in different contexts. The engine speeds in 
this map range from idle to maximum governed speed and the loads range 
from engine motoring (negative load) to the maximum load of an engine. 
When GEM runs over a vehicle duty cycle, this data table is linearly 
interpolated to find a corresponding fuel consumption mass rate at each 
engine speed and load that is demanded by the simulated vehicle 
operating over the duty cycle. The fuel consumption mass rate of the 
engine is then integrated over each duty cycle in GEM to arrive at the 
total mass of fuel consumed for the specific vehicle and duty cycle. 
Under Phase 1, manufacturers were not allowed to input their own engine 
fuel maps to represent their specific engines in the vehicle being 
simulated in GEM. Because GEM was programmed with fixed engine fuel 
maps for Phase 1 that all manufacturers had to use, interpolation of 
the tables themselves over each of the three different GEM duty cycles 
did not have to closely represent how an actual engine might operate 
over these three different duty cycles.
    In contrast, for Phase 2 we are proposing a new and required 
steady-state engine dynamometer test procedure for manufacturers to use 
to generate their own engine fuel maps to represent each of their 
engine families in GEM. The proposed Phase 2 approach is consistent 
with the 2014 NAS Phase 2 First Report recommendation.\88\ To validate 
this approach we compared the results from 28 individual engine 
dynamometer tests. Three different engines were used to generate this 
data, and these engines were produced by two different engine 
manufacturers. One engine was tested at three different power ratings 
(13 liters at 410, 450 & 475 hp) and one engine was tested at two 
ratings (6.7 liters at 240 and 300 hp), and other engine with one 
rating (15 liters 455 hp) service classes. For each engine and rating 
our proposed steady-state engine dynamometer test procedure was 
conducted to generate an engine fuel map to represent that particular 
engine in GEM. Next, with GEM we simulated various vehicles in which 
the engine could be installed. For each of the GEM duty cycles we are 
proposing, namely the urban local (ARB Transient), urban highway with 
road grade (55 mph), and rural highway with road grade (65 mph) duty 
cycles, we determined the GEM result for each vehicle configuration, 
and we saved the engine output shaft speed and torque information that 
GEM created to interpolate the steady-state engine map for each vehicle 
configuration. We then had this same engine output shaft speed and 
torque information programmed into an engine dynamometer controller, 
and we had each engine perform the same duty cycles that GEM demanded 
of the simulated version of the engine. We then compared the GEM 
results based on GEM's linear interpolation of the engine maps to the 
measured engine dynamometer results. We concluded that for the 55 mph 
and 65 mph duty cycles, GEM's interpolation of the steady-state data 
tables was sufficiently accurate versus the measured results. This is 
an outcome one would reasonably expect because even with changes in 
road grade, the 55 mph and 65 mph duty cycles do not demand rapid 
changes in engine speed or load. The 55 mph and 65 mph duty cycles are 
nearly steady-state, as far as engine operation is concerned, just like 
the engine maps themselves. However, for the ARB Transient cycle, we 
observed a consistent bias, where GEM consistently under-predicted fuel 
consumption and CO2 emissions. This low bias over the 28 
engine tests ranged from 4.2 percent low to 7.8 percent low. The mean 
was 5.9 percent low and the 90th percentile value was 7.1 percent low. 
These observations are consistent with the fact that engines generally 
operate less efficiently under transient conditions than under steady-
state conditions.
---------------------------------------------------------------------------

    \88\ National Academy of Science. ``Reducing the Fuel 
Consumption and GHG Emissions of Medium- and Heavy-Duty Vehicles, 
Phase Two, First Report.'' 2014. Recommendation 3.8.
---------------------------------------------------------------------------

    A number of reasons explain this consistent trend. For example, 
under rapidly changing engine conditions, it is generally more 
challenging to program an engine electronic controller to respond with 
optimum fuel injection rate and timing, exhaust gas recirculation valve 
position, variable nozzle turbo-charger vane position and other set 
points than it is to do so under steady-state conditions. Transient 
heat and mass transfer within the intake, exhaust, and combustion 
chambers also tend to increase turbulence and enhance energy loss to 
engine coolant during transient operation. Furthermore, because exhaust 
emissions control is more challenging under transient engine operation, 
engineering tradeoffs sometimes need to be made between fuel efficiency 
and transient emissions control. Special calibrations are typically 
also required to control smoke and manage exhaust temperatures during 
transient operation for a transient cycle. We are confident that this 
low bias in GEM would continue to exist well into the future if we were 
to test additional engines. However, with the range of the results that 
we have generated so far we are somewhat less confident in proposing a 
single numerical value to correct for this effect

[[Page 40184]]

over the ARB Transient duty cycle. Based on the data we have collected 
so far, we are conservatively proposing to apply a 5.0 percent 
correction factor to GEM's ARB Transient results. Note that adjustment 
would be applied internal to GEM, and no manufacturer input or action 
would be needed. This means that for GEM fuel consumption and 
CO2 emissions results that were generated using the steady-
state engine map representation of an engine in GEM, a 1.05 multiplier 
would be applied to only the ARB Transient result. If a manufacturer 
chooses to perform the optional powertrain test procedure we are 
proposing, then this 1.05 multiplier to the ARB Transient would not 
apply (since we know of no bias in that optional powertrain test). For 
the same reason, if we were to replace the proposed steady-state engine 
map in GEM with the alternative approach detailed in draft RIA, then 
this 1.05 multiplier would not apply. We request comment on whether or 
not this single value multiplier is an appropriate way to correct 
between steady-state and transient engine fuel consumption and 
CO2 emissions, specifically over the ARB Transient duty 
cycle. We also request comment on the magnitude of the multiplier 
itself. For example, for the proposal we have chosen a 1.05 multiplier 
correction value because it is conservative but still near the mean 
bias we observed. However, for the tests we have conducted on current 
technology engines, a 1.05 multiplier would mean that about one half of 
these engines would be penalized by powertrain testing (or if we 
utilized the alternative engine approach) because the actual measured 
transient impact would be slightly higher than 5 percent. While these 
tests were performed on current technology powertrains rather than the 
kind of optimized powertrains we project for Phase 2, these results 
raise still some concerns for us. Because we intend to incentivize 
powertrain testing and not penalize it, and because we also encourage 
constructive comments on the alternative approach, we also request 
comment on increasing the magnitude of this ARB Transient multiplier 
toward the higher end of the biases we observed. For example, we 
request comment on increasing the proposed multiplier from 1.05 to 
1.07, which is close to the 90th percentile of the results we have 
collected so far. Using this higher multiplier would imply that only 
about 10 percent of engines powertrain tested or tested under the 
alternative approach would show worse fuel consumption over the ARB 
Transient than its respective representation in a steady-state data 
table in GEM. This would mean that the remaining 90 percent of engines 
powertrain tested would receive additional credit in GEM. Using 1.07 
would essentially guarantee that any powertrain that was significantly 
more efficient than current powertrains would receive meaningful credit 
for the improvement. However, this value would also provide credits for 
many current powertrain designs.
    We also request comment as to whether or not there might be certain 
vehicle sub-categories or certain small volume vocational chassis, 
where using the Phase 1 approach of using a generic engine table might 
be more appropriate. We also request comment as to whether or not the 
agencies should provide default generic engine maps in GEM for Phase 2 
and allow manufacturers to optionally override these generic maps with 
their own maps, which would be generated according to our proposed 
engine dynamometer steady-state test procedure.
(b) Simulating Human Driver Behavior and Transmissions for Vehicle 
Certification
    GEM for Phase 1 simulates the same generic human driver behavior 
and manual transmission for all vehicles. The simulated driver responds 
to changes in the target vehicle speed of the duty cycles by changing 
the simulated positions of the vehicle's accelerator pedal, brake 
pedal, clutch pedal, and gear shift lever. For simplicity in Phase 1 
the GEM driver shifted at ideal points for maximum fuel efficiency and 
the manual transmission was simulated as an ideal transmission that did 
not have any delay time (i.e., torque interruption) between gear shifts 
and did not have any energy losses associated with clutch slip during 
gear shifts.
    In GEM for Phase 2 we are proposing to allow manufacturers to 
select one of three types of transmissions to represent the 
transmission in the vehicle they are certifying: manual transmission, 
automated manual transmission, and automatic transmission. We are 
currently in the process of developing a dual-clutch transmission type 
in GEM, but we are not proposing to allow its use in Phase 2 at this 
time. Because production of heavy-duty dual clutch transmissions has 
only begun in the past few months, we do not yet have any experimental 
data to validate our GEM simulation of this transmission type. 
Therefore, we are requesting comment on whether or not there is 
additional data available for such validation. Should such data be 
provided in comments, we may finalize GEM for Phase 2 with a fourth 
transmission types for dual clutch transmissions. We are also 
considering an option to address dual clutch transmissions through a 
post-simulation adjustment as discussed in Chapter 4 of the draft RIA.
    In the proposed modifications to GEM, the driver behavior and the 
three different transmission types are simulated in the same basic 
manner as in Phase 1, but each transmission type features a unique 
combination of driver behavior and transmission responses that match 
both the driver behavior and the transmission responses we measured 
during vehicle testing of these three transmission types. In general 
the transmission gear shifting strategy for all of the transmissions is 
designed to shift the transmission so that it is always in the most 
efficient gear for the current vehicle demand, while staying within 
certain limits to prevent unrealistically high frequency shifting. Some 
examples of these limits are torque reserve limits (which vary as 
function of engine speed), minimum time-in-gear and minimum fuel 
efficiency benefit to shift to the next gear. Some of the differences 
between the three transmission types include a driver ``double-
clutching'' during gear shifts of the manual transmission only, and 
``power shifts'' and torque converter torque multiplication, slip, and 
lock-up in automatic transmissions only. Refer to Chapter 4 of the 
draft RIA for a more detailed description of these different simulated 
driver behaviors and transmission types.
    We considered an alternative approach where transmission 
manufacturers would provide vehicle manufacturers with detailed 
information about their automated transmissions' proprietary shift 
strategies for representation in GEM. NAS also recommended this 
approach.\89\ The advantages of this approach include a more realistic 
representation of a transmission in GEM and potentially the recognition 
of additional fuel efficiency improving strategies to achieve 
additional fuel consumption and CO2 emissions reductions. 
However, there are a number of technical and policy disadvantages of 
this approach. One disadvantage is that it would require the

[[Page 40185]]

disclosure of proprietary information between competing companies 
because some vehicle manufacturers produce their own transmissions and 
also use other suppliers' transmissions. There are technical challenges 
too. For example, some transmission manufacturers have upwards of 40 
different shift strategies programmed into their transmission 
controllers. Depending on in-use driving conditions, some of which are 
not simulated in GEM (e.g., changing payloads, changing tire traction) 
a transmission controller can change its shift strategy. Representing 
dynamic switching between multiple proprietary shift strategies would 
be extremely complex to simulate in GEM. Furthermore, if the agencies 
were to propose requiring transmission manufacturers to provide shift 
strategy inputs for use in GEM, then the agencies would have to devise 
a compliance strategy to monitor in-use shift strategies, including a 
driver behavior model that could be implemented as part of an in-use 
shift strategy test. This too would be very complex. If manufacturers 
were subject to in-use compliance requirements of their transmission 
shift strategies, this could lead to restricting the use of certain 
shift strategies in the heavy-duty sector, which would in turn 
potentially lead to sub-optimal vehicle configurations that do not 
improve fuel efficiency or adequately serve the wide range of customer 
needs; especially in the vocational vehicle segment. For example, if 
the agencies were to restrict the use of more aggressive and less fuel 
efficient in-use shift strategies that are used only under heavy loads 
and steep grades, then certain vehicle applications would need to 
compensate for this loss of capability through the installation of 
over-sized and over-powered engines that are subsequently poorly 
matched and less efficient under lighter load conditions. Therefore, as 
a policy consideration to preserve vehicle configuration choice and to 
preserve the full capability of heavy-duty vehicles today, the agencies 
are intentionally not requiring transmission manufacturers to submit 
detailed proprietary shift strategy information to vehicle 
manufacturers to input into GEM. This is not unlike Phase 1, where 
unique transmission and axle attributes were not recognized at all in 
GEM. Instead, the agencies are proposing that vehicle manufacturers 
choose from among the three transmission types that the agencies have 
already developed, validated, and programmed into GEM. The vehicle 
manufacturers would then enter into GEM their particular transmission's 
number of gears and gear ratios. The agencies recognize that designing 
GEM like this would exclude a potentially significant reduction from 
the GEM simulation. However, if a manufacturer chooses to use the 
optional powertrain test procedure, then the agencies' transmission 
types in GEM would be overridden by the actual data collected during 
the powertrain test, which would recognize the actual benefit of the 
transmission. Note that the optional powertrain test procedure is only 
advantageous to a vehicle manufacturer if an actual transmission is 
more efficient and has a superior shift strategy compared to its 
respective transmission type simulated in GEM.
---------------------------------------------------------------------------

    \89\ Transportation Research Board 2014. ``Reducing the Fuel 
Consumption and Greenhouse Gas Emissions of Medium- and Heavy-Duty 
Vehicles, Phase Two.'' (``Phase 2 First Report'') Washington, DC, 
The National Academies Press. Cooperative Agreement DTNH22-12-00389. 
Available electronically from the National Academy Press Web site at 
http://www.nap.edu/catalog.php?record_id=12845 (last accessed 
December 2, 2014). Recommendation 3.7.
---------------------------------------------------------------------------

(c) Simulating Axles for Vehicle Certification
    In GEM for Phase 1 the axle ratio of the primary drive axle and the 
energy losses assumed in the simulated axle itself were the same for 
all vehicles. For Phase 2 we are proposing that the vehicle 
manufacturer input into GEM the axle ratio of the primary drive axle. 
This input would recognize the intent to operate the engine at a 
particular engine speed when the transmission is operating in its 
highest transmission gear; especially for the 55 mph and 65 mph duty 
cycles in GEM. This input facilitates GEM's recognition of vehicle 
designs that take advantage of operating the engine at the lowest 
possible engine speeds. This is commonly known as ``engine down-
speeding'', and the general rule-of-thumb for heavy-duty engines is 
that for every 100 rpm decrease in engine speed, there can be about a 1 
percent decrease in fuel consumption and CO2 emissions. 
Therefore, it is important that GEM allow this value to be input by the 
vehicle manufacturer. Axle ratio is also straightforward to verify 
during any in-use compliance audit.
    We are proposing a fixed axle ratio energy efficiency of 95.5 
percent at all speeds and loads, but are requesting comment on whether 
this pre-specified efficiency is reasonable. However, we know that this 
efficiency actually varies as a function of axle speed and axle input 
torque. Therefore, as an exploratory test we have created a modified 
version of GEM that has as an input a data table of axle efficiency as 
a function of axle speed and axle torque. The modified version of GEM 
subsequently interpolates this table over each of the duty cycles to 
represent a more realistic axle efficiency at each point of each duty 
cycle. We have also created a draft axle ratio efficiency test 
procedure that requires the use of a dynamometer test facility. This 
procedure includes the use of a baseline fuel-efficient synthetic gear 
lubricant manufactured by BASF.\90\ This baseline will be used to gauge 
improvements in axle design and lubricants. The draft test procedure 
includes initial feedback that we have received from axle manufacturers 
and our own engineering judgment. Refer to 40 CFR 1037.560 of the Phase 
2 proposed regulations, which contain this draft test procedure. This 
test procedure could be used to generate the results needed to create 
the axle efficiency data table for input into GEM. However, the 
agencies have not yet conducted experimental tests of axles using this 
draft test procedure so we are reluctant to propose this test procedure 
as either mandatory or even optional at this time. Rather we request 
comment as to whether or not we should finalize this test procedure and 
either require its use or allow its use optionally to determine an axle 
efficiency data table as an input to GEM, which would override the 
fixed axle efficiency we are proposing at this time. We also request 
comment on improving or otherwise refining the test procedure itself. 
Note that the agencies believe that allowing the GEM default axle 
efficiency to be replaced by manufacturer inputs only makes sense if 
the manufacturer inputs is are the results of a specified test 
procedure that we could verify by our own independent testing of the 
axle.
---------------------------------------------------------------------------

    \90\ BASF TI/EVO 0137 e, Emgard[supreg] FE 75W-90 Fuel Efficient 
Synthetic Gear Lubricant.
---------------------------------------------------------------------------

    In addition to proposing to require the primary drive axle ratio 
input into GEM (and potentially an option to input an actual axle 
efficiency data table), we are also proposing that the vehicle 
manufacturer input into GEM whether or not one or two drive axles are 
driven by the engine. When a heavy-duty vehicle is equipped with two 
rear axles where both are driven by the engine, this is called a 
``6x4'' configuration. ``6'' refers to the total number of wheel hubs 
on the vehicle. In the 6x4 configuration there are two front wheel hubs 
for the two steer wheels and tires plus four rear wheel hubs for the 
four rear wheels and tires (or more commonly four sets of rear dual 
wheels and tires). ``4'' refers to the number of wheel hubs driven by 
the engine. These are the two rear axles that have two wheel hubs each. 
Compared to a 6x4 configuration a 6x2 configuration decreases axle 
energy loss due to friction and oil pumping in two driven axles, by 
driving only one axle. The decrease in fuel consumption and 
CO2 emissions associated with a 6x2 versus 6x4 axle 
configuration is estimated to be

[[Page 40186]]

2.5 percent.\91\ Therefore, in the proposed Phase 2 version of GEM, if 
a manufacturer simulates a 6x2 axle configuration, GEM decreases the 
overall GEM result by 2.5 percent. Note that GEM will similarly 
decrease the overall GEM result by 2.5 percent for a 4x2 tractor or 
Class 8 vocational chassis configuration if it has only two wheel hubs 
driven. Note that we are not proposing that GEM have an option to 
increase the overall GEM result by some percentage by selecting, say, a 
6x6 or 8x8 option if the front axle(s) are driven. Because these 
configurations are only manufactured for specialized vehicles that 
require extra traction for off-road applications, they are very low 
volume sales and their increased fuel consumption and CO2 
emissions are not significant in comparison to the overall reductions 
of the proposed Phase 2 program. Note that 40 CFR 1037.631 (for off-
road vocational vehicles), which is being continued from the Phase 1 
program, would likely exempt many of these vehicles from the vehicle 
standards.
---------------------------------------------------------------------------

    \91\ NACFE. Executive Report--6x2 (Dead Axle) Tractors. November 
2010. See Docket EPA-HQ-OAR-2014-0827.
---------------------------------------------------------------------------

    Instead of directly modeling 6x4 or 6x2 axle configuration, we are 
proposing use of a post-simulation adjustment approach discussed in 
Chapter 4 of the drat RIA to model benefits of different axle 
configuration.
(d) Simulating Accessories for Vehicle Certification
    Phase 1 GEM uses a fixed power consumption value to simulate the 
fuel consumed for powering accessories such as power steering pumps and 
alternators. While the agencies are not proposing any changes to this 
approach for Phase 2, we are requesting comment on whether or not we 
should allow some manufacturer input to reflect the installation of 
accessory components that result in lower accessory loads. For example, 
we could consider an accessory load reduction GEM input based on 
installing a number of qualifying advanced accessory components that 
could be in production during Phase 2. We request comment on 
identifying such advanced accessory components, and we request comment 
on defining these components in such a way that they can be 
unambiguously distinguished from other similar components that do not 
decrease accessory loads. We also request comment on how much of a 
decrease in accessory load should be programmed into GEM if qualifying 
advanced accessory components are installed.
(e) Aerodynamics for Tractor, Vocational Vehicle, and Trailer 
Certification
    For GEM in Phase 2 the agencies propose to simulate aerodynamic 
drag in largely the same manner as in Phase 1. For vocational chassis 
we propose to continue to use the same prescribed products of drag 
coefficient times vehicle frontal area (Cd*A) that were predefined for 
each of the vocational subcategories in Phase 1. For tractors we 
propose to continue to use an aerodynamic bin approach similar to the 
one that exists in Phase 1 today. This approach requires tractor 
manufacturers to conduct a certain amount of coast-down vehicle 
testing, although manufacturers have the option to conduct scaled wind 
tunnel testing and/or computational fluid dynamics modeling. The 
results of these tests determine into which bin a vehicle is assigned. 
Then in GEM the aerodynamic drag coefficient for each vehicle in the 
same bin is the same. This approach helps to account for limits in the 
repeatability of aerodynamic testing and it creates a compliance margin 
since any test result which keeps the vehicle in the same aerodynamic 
bin is considered compliant. However, for Phase 2 we are proposing new 
boundary values for the bins themselves and we are adding two 
additional bins in order to recognize further advances in aerodynamic 
drag reduction beyond what was recognized in Phase 1. Furthermore, 
while Phase 1 GEM used predefined frontal areas for tractors while the 
manufacturers input a Cd value, the agencies propose that manufacturers 
would use a measured drag area (CdA) value for each tractor 
configuration for Phase 2. See 40 CFR 1037.525.
    In addition to these proposed changes we are proposing a number of 
aerodynamic drag test procedure improvements. One proposed improvement 
is to update the so-called standard trailer that is prescribed for use 
during aerodynamic drag testing of a tractor--that is, the hypothetical 
trailer modeled in GEM to represent a trailer paired with the tractor 
in actual use. In Phase 1 a non-aerodynamic 53-foot long box-shaped dry 
van trailer was specified as the standard trailer for tractor 
aerodynamic testing (see 40 CFR 1037.501(g)). For Phase 2 we are 
proposing to modify this standard trailer for tractor testing to make 
it more similar to the trailers we would require to be produced during 
the Phase 2 timeframe. More specifically, we would prescribe the 
installation of aerodynamic trailer skirts (and low rolling resistance 
tires as applied in Phase 1) on the reference trailer, as discussed in 
further in Section III.E.2. As explained more fully in Sections III and 
IV below, the agencies believe that tractor-trailer pairings will be 
optimized aerodynamically to a significant extent in-use (such as using 
high-roof cabs when pulling box trailers), and that this real-world 
optimization should be reflected in the certification testing. We also 
request comment on whether or not the Phase 2 standard trailer should 
include the installation of other aerodynamic devices such as a nose 
fairing, an under tray, or a boat tail or trailer tail. Would a 
standard trailer including these additional components make the tractor 
program better?
    Another proposed aerodynamic test procedure improvement is intended 
to better account for average wind yaw angle to better reflect the true 
impact of aerodynamic features on the in-use fuel consumption and 
CO2 emissions of tractors. Refer to the proposed test 
procedures in 40 CFR 1037.525 for further details of these aerodynamic 
test procedures.
    For trailer certification, the agencies are proposing to use GEM in 
a different way than GEM is used for tractor certification in Phase 1 
and Phase 2. As described in Section IV, the proposed trailer standards 
are based on GEM simulation, but trailer manufacturers would not run 
GEM for certification. Instead, manufacturers would use a simple 
equation to replicate GEM performance from the inputs. As with GEM, the 
only technologies recognized by this GEM-based equation for trailer 
certification are aerodynamic technologies, tire technologies 
(including tire rolling resistance and automatic tire inflation 
systems), and some weight reduction technologies. Note that since the 
purpose of this equation is to measure GEM performance, it can be 
considered as simply another form of the model using a different input 
interface. Thus, for simplicity, the remainder of this Section II. C. 
sometimes discusses GEM as being used for trailers, without regard to 
how manufacturers will actually input GEM variables.
    Similar to tractor certification, we propose that trailer 
manufacturers may at their option conduct some amount of aerodynamic 
testing (e.g., coast-down testing, scale wind tunnel testing, 
computational fluid dynamics modeling, or possibly aerodynamic 
component testing) and use this information with the equation.\92\ In 
this

[[Page 40187]]

case the agencies propose the configuration of a reference tractor for 
conducting trailer testing. Refer to Section IV of this preamble and to 
40 CFR 1037.501 of the proposed regulations for details on the proposed 
reference tractor configuration for trailer test procedures.
---------------------------------------------------------------------------

    \92\ The agencies project that more than enough aerodynamic 
component vendors would take advantage of proposed optional pre-
approval process to make trailer manufacturer testing optional.
---------------------------------------------------------------------------

(f) Tires and Tire Inflation Systems for Truck and Trailer 
Certification
    For GEM in Phase 1 vehicle manufacturers input the tire rolling 
resistance of steer and drive tires directly into GEM. The agencies 
prescribed an internationally recognized tire rolling resistance test 
procedure, ISO 28580, for determining the tire rolling resistance value 
that is input into GEM, as described in 40 CFR 1037.520(c). For Phase 2 
we are proposing to continue this same approach and the use of ISO 
28580, and we propose to expand these requirements to trailer tires as 
well. We request comment on whether specific modifications to this test 
procedure would improve its accuracy, repeatability or its test lab to 
test lab variability.
    In addition to tire rolling resistance, we are proposing that for 
Phase 2 vehicle manufacturers enter into GEM the tire manufacturer's 
specified tire loaded radius for the vehicle's drive tires. This value 
is commonly reported by tire manufacturers already so that vehicle 
speedometers can be adjusted appropriately. This input value is needed 
so that GEM can accurately convert simulated vehicle speed into axle 
speed, transmission speed, and ultimately engine speed. We request 
comment on whether the proposed test procedure should be modified to 
measure the tire's revolutions per distance directly, as opposed to 
using the loaded radius to calculate the drive axle rotational speed 
from vehicle speed.
    For tractors and trailers, we propose to allow manufacturers to 
specify whether or not an automatic tire inflation system is installed. 
If one is installed, GEM, or in the case of trailers, the equations 
based on GEM, would assign a 1 percent decrease in the overall fuel 
consumption and CO2 emissions simulation results for 
tractors, and a 1.5 percent decrease for trailers. This would be done 
through post-simulation adjustments discussed in Chapter 4 of the draft 
RIA. In contrast, we are not proposing to assign any decrease in fuel 
consumption and CO2 emissions for tire pressure monitoring 
systems. We do recognize that some drivers would respond to a warning 
indication from a tire pressure monitoring system, but we are unsure 
how to assign a fixed decrease in fuel consumption and CO2 
emissions for tire pressure monitoring systems. We would estimate that 
the value would be less than any value we would assign for an automatic 
tire inflation system. We request comment on whether or not we should 
assign a fixed decrease in fuel consumption and CO2 
emissions for tire pressure monitoring systems, and if so, we request 
comment on what would be an appropriate assigned fixed value.
(g) Weight Reduction for Tractor, Vocational Chassis and Trailer 
Certification
    We propose for Phase 2 that GEM continues the weight reduction 
recognition approach in Phase 1, where the agencies prescribe fixed 
weight reductions, or ``deltas'', for using certain lightweight 
materials for certain vehicle components. In Phase 1 the agencies 
published a list of weight reductions for using high-strength steel and 
aluminum materials on a part by part basis. For Phase 2 we propose to 
use these same values for high-strength steel and aluminum parts for 
tractors and for trailers and we have scaled these values for use in 
certifying the different weight classes of vocational chassis. In 
addition we are proposing a similar part by part weight reduction list 
for tractor parts made from thermoplastic material. We are also 
proposing to assign a fixed weight increase to natural gas fueled 
vehicles to reflect the weight increase of natural gas fuel tanks 
versus gasoline or diesel tanks. This increase would be allocated 
partly to the chassis and from the payload using the same allocation as 
weight reductions for the given vehicle type. For tractors we are 
proposing to continue the same mathematical approach in GEM to assign 
1/3 of a total weight decrease to a payload increase and 2/3 of the 
total weight decrease to a vehicle mass decrease. For Phase 1 these 
ratios were based on the average frequency that a tractor operates at 
its gross combined weight rating. Therefore, we propose to use these 
ratios for trailers in Phase 2. However, as with the other fuel 
consumption and GHG reducing technologies manufacturers use for 
compliance, reductions associated with weight reduction would be 
calculated using the trailer compliance equation rather than GEM. For 
vocational chassis, for which Phase 1 did not address weight reduction, 
we propose a 50/50 ratio. In other words, for vocational chassis in GEM 
we propose to assign 1/2 of a total weight decrease to a payload 
increase and 1/2 of the total weight decrease to a vehicle mass 
decrease. We request comment on all aspects of applying weight 
reductions in GEM, including proposed weight increases for alternate 
fuel vehicles and whether a 50/50 ratio is appropriate for vocational 
chassis.
(h) GEM Duty Cycles for Tractor, Vocational Chassis and Trailer 
Certification
---------------------------------------------------------------------------

    \93\ SwRI road grade testing and GEM validation report, 2014.
---------------------------------------------------------------------------

    In Phase 1, there are three GEM vehicle duty cycles that 
represented stop-and-go city driving (ARB Transient), urban highway 
driving (55 mph), and rural interstate highway driving (65 mph). In 
Phase 1 these cycles were time-based. That is, they were specified as a 
function of simulated time and the duty cycles ended once the specified 
time elapsed in simulation. The agencies propose to use these three 
drive cycles in Phase 2, but with some revisions. First the agencies 
propose that GEM would simulate these cycles on a distance-based 
specification, rather than on a time-based specification. A distance-
based specification ensures that even if a vehicle in simulation does 
not always achieve the target vehicle speed, the vehicle will have to 
continue in simulation for a longer period of time to complete the duty 
cycle. This ensures that vehicles are evaluated over the complete 
distance of the duty cycle and not just the portion of the duty cycle 
that a vehicle completes in a given time period. A distance-based duty 
cycle specification also facilitates a straightforward specification of 
road grade as a function of distance along the duty cycle. For Phase 2 
the agencies are proposing to enhance the 55 mph and 65 mph duty cycles 
by adding representative road grade to exercise the simulated vehicle's 
engine, transmission, axle, and tires in a more realistic way. A flat 
road grade profile over a constant speed test does not present many 
opportunities for a transmission to shift gears, and may have the 
unintended consequence of enabling underpowered vehicles or excessively 
downsped drivetrains to generate credits. The road grade profile 
proposed is the same for both the 55 mph and 65 mph duty cycles, and 
the profile was based on real over-the-road testing the agencies 
directed under an agency-funded contract with Southwest Research 
Institute.\93\ See Section III.E for more details on development of the 
proposed road grade profile. The agencies are continuing to evaluate

[[Page 40188]]

alternate road grade profiles including actual sections of restricted 
access highway with road grades that are statistically similar to the 
national road grade profile as well as purely synthetic road grade 
profiles.\94\ We request comments on the proposed road grade profile, 
and would welcome additional statistical evaluations of this road grade 
profile and other road grade profiles for comparison. We believe that 
the enhancement of the 55 mph and 65 mph duty cycles with road grade is 
consistent with the NAS recommendation regarding road grade.\95\
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    \94\ See National Renewable Energy Laboratory report ``EPA GHG 
Certification of Medium- and Heavy-Duty Vehicles: Development of 
Road Grade Profiles Representative of US Controlled Access 
Highways'' dated May 2015 and EPA memorandum ``Development of an 
Alternative, Nationally Representative, Activity Weighted Road Grade 
Profile for Use in EPA GHG Certification of Medium- and Heavy-Duty 
Vehicles'' dated May 13, 2015, both available in Docket EPA-HQ-OAR-
2014-0827. This docket also includes file 
NREL_SyntheticAndLocalGradeProfiles.xlsx which contains numerical 
representations of all road grade profiles described in the NREL 
report.
    \95\ NAS 2010 Report. Page 189. ``A fundamental concern raised 
by the committee and those who testified during our public sessions 
was the tension between the need to set a uniform test cycle for 
regulatory purposes, and existing industry practices of seeking to 
minimize the fuel consumption of medium and heavy-duty vehicles 
designed for specific routes that may include grades, loads, work 
tasks or speeds inconsistent with the regulatory test cycle. This 
highlights the critical importance of achieving fidelity between 
certification values and real-world results to avoid decisions that 
hurt rather than help real-world fuel consumption.''
---------------------------------------------------------------------------

    We recognize that even with the proposed road grade profile, GEM 
may continue to under predict the number of transmission shifts of 
vehicles on restricted access highways if the model simulates constant 
speeds. We request comment on other ways in which the proposed 55 mph 
and 65 mph duty cycles could be enhanced. For example, we request 
comment on whether a more aggressive road grade profile would induce a 
more realistic and representative number of transmission gear shifts. 
We also request comment on whether we should consider varying the 
vehicle target speed over the 55 mph and/or 65 mph duty cycles to 
simulate human driver behavior reacting to traffic congestion. This 
would increase the number of shifts during the 55 mph and 65 mph duty 
cycles, though it may be possible for an equivalent effect to be 
achieved by assigning a greater weighting to the transient cycle in the 
GEM composite test score.
(i) Workday Idle Operation for Vocational Vehicle Certification
    In the Phase 1 program, reduction in idle emissions was recognized 
only for sleeper cab tractors, and only with respect to hotelling idle, 
where a driver needs power to operate heating, ventilation, air 
conditioning and other electrical equipment in order to use the sleeper 
cab to eat, rest, or conduct other business. As described in Section V, 
the agencies are now proposing to recognize in GEM technologies that 
reduce workday idle emissions, such as automatic stop-start systems and 
automatic transmissions that shift to neutral at idle. Many vocational 
vehicle applications operate on patterns implicating workday idle 
cycles, and the agencies are proposing test procedures in GEM to 
account specifically for these cycles and potential controls. GEM would 
recognize these idle controls in two ways. For technologies like 
neutral-idle that address idle that occurs during the transient cycle 
(representing the type of operation that would occur when the vehicle 
is stopped at a stop light), GEM would interpolate lower fuel rates 
from the engine map. For technologies like start-stop and auto-shutdown 
that eliminate some of the idle that occurs when a vehicle is stopped 
or parked, GEM would assign a value of zero fuel rate for what we are 
proposing as an ``idle cycle''. This idle cycle would be weighted along 
with the 65 mph, 55 mph, and ARB Transient duty cycles according to the 
vocational chassis duty cycle weighting factors that we are proposing 
for Phase 2. These weighting factors are different for each of the 
three vocational chassis speed categories that we are proposing for 
Phase 2. While we are not proposing to apply this idle cycle for 
tractors, we do request comment on whether or not we should consider a 
applying this idle cycle to certain tractor types, like day cabs that 
could experience more significant amounts of time stopped or parked as 
part of an urban delivery route. We also request comment on whether or 
not start-stop or auto-shutdown technologies are being developed for 
tractors; especially for Class 7 and 8 day cabs that could experience 
more frequent stops and more time parked for deliveries.
(2) Validation of the Proposed GEM
    After making the proposed changes to GEM, the agencies validated 
the model in comparison to over 130 vehicle variants, consistent with 
the recommendation made by the NAS in their Phase 2-First Report.\96\ 
As is described in Chapter 4 of the Draft RIA, good agreement was 
observed between GEM simulations and test data over a wide range of 
vehicles. In general, the model simulations agreed with the test 
results within 5 percent on an absolute basis. As pointed 
out in Chapter 4.3.2 of the RIA, relative accuracy is more relevant to 
this rulemaking. This is because all of the numeric standards proposed 
for tractors, trailers and vocational chassis are derived from running 
GEM first with Phase 1 ``baseline'' technology packages and then with 
various candidate Phase 2 technology packages. The differences between 
these GEM results are examined to select stringencies. In other words, 
the agencies used the same version of GEM to establish the standards as 
was used to evaluate baseline performance for this rulemaking. 
Therefore, it is most important that GEM accurately reflects relative 
changes in emissions for each added technology. For vehicle 
certification purposes it is less important that GEM's absolute value 
of the fuel consumption or CO2 emissions are accurate 
compared to laboratory testing of the same vehicle. The ultimate 
purpose of this new version of GEM will be to evaluate changes or 
additions in technology, and compliance is demonstrated on a relative 
basis to the numerically standards that were also derived from GEM. 
Nevertheless, the agencies concluded that the absolute accuracy of GEM 
is generally within 5 percent, as shown in Figure II-1. 
Chapter 4.3.2 of the draft RIA shows that relative accuracy is even 
better, 2-3 percent.
---------------------------------------------------------------------------

    \96\ National Academy of Science. ``Reducing the Fuel 
Consumption and GHG Emissions of Medium- and Heavy-Duty Vehicles, 
Phase Two, First Report.'' 2014. Recommendation1.2.

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[[Page 40189]]

[GRAPHIC] [TIFF OMITTED] TP13JY15.000

    In addition to this successful validation against experimental 
results, the agencies have also initiated a peer review of the proposed 
GEM source code. This peer review has been submitted to Docket # EPA-
HQ-OAR-2014-0827.
(3) Supplements to GEM Simulation
    As in Phase 1, for most tractors and vocational vehicles, 
compliance with the Phase 2 g/ton-mile vehicle standards could be 
evaluated by directly comparing the GEM result to the standard. 
However, in Phase 1, manufacturers incorporating innovative or advanced 
technologies could apply improvement factors to lower the GEM result 
slightly before comparing to the standard.\97\ For example, a 
manufacturer incorporating a launch-assist mild hybrid that was 
approved for a 5 percent benefit would apply a 0.95 improvement factor 
to its GEM results for such vehicles. In this example, a GEM result of 
300 g/ton-mile would be reduced to 285 g/ton-mile.
---------------------------------------------------------------------------

    \97\ 40 CFR 1036.610, 1036.615, 1037.610, and 1037.615
---------------------------------------------------------------------------

    For Phase 2, the agencies are proposing to largely continue the 
existing Phase 1 innovative technology approach. We are also proposing 
to create a parallel option specifically related to innovative 
powertrain designs. These proposals are discussed below.
(a) Innovative/Off-Cycle Technology Procedures
    In Phase 1 the agencies adopted an emissions credit generating 
opportunity that applied to new and innovative technologies that reduce 
fuel consumption and CO2 emissions, that were not in common 
use with heavy-duty vehicles before model year 2010 and are not 
reflected over the test procedures or GEM (i.e., the benefits are 
``off-cycle''). See 76 FR 57253. As was the case in the development of 
Phase 1, the agencies are proposing to continue this approach for 
technologies and concepts with CO2 emissions and fuel 
consumption reduction potential that might not be adequately captured 
over the proposed Phase 2 duty cycles or are not proposed inputs to 
GEM. Note, however, that the agencies are proposing to refer to these 
technologies as off-cycle rather than innovative. See Section I for 
more discussion of innovative and off-cycle technologies.
    We recognize that the Phase 1 testing burden associated with the 
innovative technology credit provisions discouraged some manufacturers 
from applying. To streamline recognition of many technologies, default 
values have been integrated directly into GEM. For example, automatic 
tire inflation systems and 6x2 axles both have fixed default values, 
recognized through a post-simulation adjustment approach discussed in 
Chapter 4 of the draft RIA. This is similar to the technology ``pick 
list'' from our light-duty programs. See 77 FR 62833-62835 (October 15, 
2012). If manufacturers wish to receive additional credit beyond these 
fixed values, then the innovative/off-cycle technology credit 
provisions would provide the regulatory path toward that additional 
recognition.
    Beyond the additional technologies that the agencies have added to 
GEM, the agencies also believe there are several emerging technologies 
that are being developed today, but would not be accounted for in GEM 
as we are proposing it because we do not have enough information about 
these technologies to assign fixed values to them in GEM. Any credits 
for these technologies would need to be based on the off-cycle 
technology credit generation provisions. These require the assessment 
of real-world fuel consumption and GHG reductions that can be measured 
with verifiable test methods using representative operating conditions 
typical of the engine or vehicle application.
    As in Phase 1, the agencies are proposing to continue to provide 
two

[[Page 40190]]

paths for approval of the test procedure to measure the CO2 
emissions and fuel consumption reductions of an off-cycle technology 
used in the HD tractor. See 40 CFR 1037.610 and 49 CFR 535.7. The first 
path would not require a public approval process of the test method. A 
manufacturer can use ``pre-approved'' test methods for HD vehicles 
including the A-to-B chassis testing, powerpack testing or on-road 
testing. A manufacturer may also use any developed test procedure which 
has known quantifiable benefits. A test plan detailing the testing 
methodology is required to be approved prior to collecting any test 
data. The agencies are also proposing to continue the second path which 
includes a public approval process of any testing method which could 
have questionable benefits (i.e., an unknown usage rate for a 
technology). Furthermore, the agencies are proposing to modify its 
provisions to better clarify the documentation required to be submitted 
for approval aligning them with provisions in 40 CFR 86.1869-12, and 
NHTSA is separately proposing to prohibit credits from technologies 
addressed by any of its crash avoidance safety rulemakings (i.e., 
congestion management systems). We welcome recommendations on how to 
improve or streamline the off-cycle technology approval process.
    Sections III and V describe tractor and vocational vehicle 
technologies, respectively, that the agencies anticipate may qualify 
for these off-cycle credit provisions.
(b) Powertrain Testing
    The agencies are proposing a powertrain test option to allow for a 
robust way to quantify the benefits of CO2 reducing 
technologies that are a part of the powertrain (conventional or hybrid) 
that are not captured in the GEM simulation. Powertrain testing and 
certification was included as one of the NAS recommendations in the 
Phase 2 -First Report.\98\ Some of these improvements are transient 
fuel control, engine and transmission control integration and hybrid 
systems. To limit the amount of testing, the powertrain would be 
divided into families and powertrains would be tested in a limited 
number of simulated vehicles that cover the range of vehicles in which 
the powertrain would be installed. The powertrain test results would 
then be used to override the engine and transmission simulation portion 
of GEM.
---------------------------------------------------------------------------

    \98\ National Academy of Science. ``Reducing the Fuel 
Consumption and GHG Emissions of Medium- and Heavy-Duty Vehicles, 
Phase Two, First Report.'' 2014. Recommendation 1.6. However, the 
agencies are not proposing to allow for the use of manufacturer 
derived and verified models of the powertrain within GEM.
---------------------------------------------------------------------------

    The largest proposed change from the Phase 1 powertrain procedure 
is that only the advanced powertrain would need to be tested (as 
opposed to the Phase 1 requirement where both the advanced powertrain 
and the conventional powertrain had to be tested). This change is 
possible because the proposed GEM simulation uses the engine fuel map 
and torque curve from the actual engine in the vehicle to be certified. 
For the powertrain results to be used broadly across all the vehicles 
that the powertrain would go into, a matrix of 8 to 9 tests would be 
needed per vehicle cycle. These tests would cover the range of 
coefficient of drag, coefficient of rolling resistance, vehicle mass 
and axle ratio of the vehicles that the powertrain will be installed 
in. The main output of this matrix of tests would be fuel mass as a 
function of positive work and average transmission output speed over 
average vehicle speed. This matrix of test results would then be used 
to calculate the vehicle's CO2 emissions by taking the work 
per ton-mile from the GEM simulation and multiplying it by the 
interpolated work specific fuel mass from the powertrain test and mass 
of CO2 to mass of fuel ratio.
    Along with proposing changes to how the powertrain results are 
used, the agencies are also proposing changes to the procedures that 
describe how to carry out a powertrain test. The changes are to give 
additional guidance on controlling the temperature of the powertrains 
intake-air, oil, coolant, block, head, transmission, battery, and power 
electronics so that they are within their expected ranges for normal 
operation. The equations that describe the vehicle model are proposed 
to be changed to allow for input of the axle's efficiency, driveline 
rotational inertia, as well as the mechanical and electrical accessory 
loads.
    The determine the positive work and average transmission output 
speed over average vehicle speed in GEM for the vehicle that will be 
certified, the agencies have defined a generic powertrain for each 
vehicle category. The agencies are requesting comment on if the generic 
powertrains should be modified according to specific aspects of the 
actual powertrain. For example using the engine's rated power to scale 
the generic engine's torque curve. Similarly, the transmission gear 
ratios could be scaled by the axle ratio of the drive axle, to make 
sure the generic engine is operated in GEM at the correct engine speed.
(4) Production Vehicle Testing for Comparison to GEM
    The agencies are is proposing to require tractor and vocational 
vehicle manufacturers to annually chassis test 5 production vehicles 
over the GEM cycles to verify that relative reductions simulated in GEM 
are being achieved in actual production. See 40 CFR 1037.665. We would 
not expect absolute correlation between GEM results and chassis 
testing. GEM makes many simplifying assumptions that do not compromise 
its usefulness for certification, but do cause it to produce emission 
rates different from what would be measured during a chassis 
dynamometer test. Given the limits of correlation possible between GEM 
and chassis testing, we would not expect such testing to accurately 
reflect whether a vehicle was compliant with the GEM standards. 
Therefore, we are proposing to not apply compliance liability to such 
testing. Rather, this testing would be for informational purposes only. 
However, we do expect there to be correlation in a relative sense. 
Vehicle to vehicle differences showing a 10 percent improvement in GEM 
should show a similar percent improvement with chassis dynamometer 
testing. Nevertheless, manufacturers would not be subject to recall or 
other compliance actions if chassis testing did not agree with the GEM 
results on a relative basis. Rather, the agencies would continue 
evaluate in-use compliance by verifying GEM inputs and testing in-use 
engines.
    EPA believes this chassis test program is necessary because of our 
experience implementing regulations for heavy-duty engines. In the 
past, manufacturers have designed engines that have much lower 
emissions on the duty cycles than occur during actual use. By proposing 
this simple test program, we hope to be able to identify such issues 
earlier and to dissuade any attempts to design solely to the 
certification test. We also expect the results of this testing to help 
inform the need for any further changes to GEM.
    As already noted in Section II.B.(1), it can be expensive to build 
chassis test cells for certification. However, EPA is proposing to 
structure this pilot-scale program to minimize the costs. First, we are 
proposing that this chassis testing would not need to comply with the 
same requirements as would apply for official certification testing. 
This would allow testing to be performed in developmental test cells 
with simple portable analyzers. Second, since the proposed program 
would require only 5 tests per year, manufacturers without

[[Page 40191]]

their own chassis testing facility would be able to contract with a 
third party to perform the testing. Finally, EPA proposes to apply this 
testing to only those manufacturers with annual production in excess of 
20,000 vehicles.
    We request comment on this proposed testing requirement. Commenters 
are encouraged to suggest alternate approaches that could achieve the 
assurance that the projected emissions reductions would occur in actual 
use.
(5) Use of GEM in Establishing Proposed Numerical Standards
    Just like in Phase 1, the agencies are proposing specific numerical 
standards against which tractors and vocational vehicles would be 
evaluated using GEM (We propose that trailers use a simplified 
equation-based approach that was derived from GEM). Although the 
proposed standards are performance-based standards, which do not 
specifically require the use of any particular technologies, the 
agencies established the proposed standards by evaluating specific 
vehicle technology packages using a prepublication version of the Phase 
2 GEM. This prepublication version was an intermediate version of the 
GEM source code, rather than the executable file version of GEM, which 
is being docketed for this proposal and is available on EPA's GEM Web 
page. Both the GEM source code and the GEM executable file are 
generally functionally equivalent.
    The agencies determined the proposed numerical standards 
essentially by evaluating certain specific technology packages 
representing the packages we are projecting to be feasible in the Phase 
2 time frame. For each technology package, GEM was used determine a 
cycle-weighted g/ton-mile emission rate and a gal/1,000 ton-mile fuel 
consumption rate. These GEM results were then essentially averaged 
together, weighted by the adoption rates the agencies are projecting 
for each technology package and for each model year of standards. 
Consider as an oversimplified example of two technology packages for 
Class 8 low-roof sleepers cabs: one package that resulted in 60 g/ton-
mile and a second that resulted in 80 g/ton-mile. If we project that 
the first package could be applied to 50 percent of the Class 8 low-
roof sleeper cab fleet in MY 2027, and that the rest of the fleet could 
do no better than the second technology package, then we would set the 
fleet average standard at 70 g/ton-mile (0.5 [middot] 60 + 0.5 [middot] 
80 = 70).
    Formal external peer review and expert external user review was 
then conducted on the version of the GEM source code that was used to 
calculate the numerical values of the proposed standards. It was 
discovered via these external review processes that the GEM source code 
contained some minor software ``bugs.'' These bugs were then corrected 
by EPA and the Phase 2 proposed GEM executable file was derived from 
this corrected version of the GEM source code. Moreover, we expect to 
also receive technical comments during the comment period that could 
potentially identify additional GEM software bugs, which would lead EPA 
to make additional changes to GEM before the Final Rule. Nevertheless, 
EPA has repeated the analysis described above using the corrected 
version of the GEM source code that was used to create the proposed GEM 
executable file. The results of this analysis are available in the 
docket to this proposal.\99\
---------------------------------------------------------------------------

    \99\ See Memorandum to the Docket ``Numerical Standards for 
Tractors, Trailers, and Vocational Vehicles Based on the June 2015 
GEM Executable Code.
---------------------------------------------------------------------------

    Thus, even without the agencies making any changes in our 
projections of technology effectiveness or market adoption rates, it is 
likely that further revisions to GEM could result in us finalizing 
different numerical values for the standards. It is important to note 
that the agencies would not necessarily consider such GEM-based 
numerical changes by themselves to be changes in the stringency of the 
standards. Rather, we believe that stringency is more appropriately 
evaluated in technological terms; namely, by evaluating technology 
effectiveness and the market adoption rates of technologies. 
Nevertheless, the agencies will docket any updates and supporting 
information in a timely manner.

D. Proposed Engine Test Procedures and Engine Standards

    For the most part, the proposed Phase 2 engine standards are a 
continuation of the Phase 1 program, but with more stringent standards 
for compression-ignition engines. Nevertheless, the agencies are 
proposing important changes related to the test procedures and 
compliance provisions. These changes are described below.
    As already discussed in Section II.B. the agencies are proposing a 
regulatory structure in which engine technologies are evaluated using 
engine-specific test procedures as well using GEM, which is vehicle-
based. We are proposing separate standards for each procedure. The 
proposed engine standards described in Section II.D.(2) and the 
proposed vehicle standards described in Sections III and V are based on 
the same engine technology, which is described in Section II.D.(2). We 
request comment on whether the engine and vehicle standards should be 
based on the same projected technology. As described below, while the 
agencies projected the same engine technology for engine standards and 
for vehicle standards, we separately projected the technology that 
would be appropriate for:

 Gasoline vocational engines and vehicles
 Diesel vocational engines and vehicles
 Tractor engines and vehicles

    Before addressing the engine standards and engine technology in 
Section II.D.(2), the agencies describe the test procedures that would 
be used to evaluate these technologies in Section II.D.(1) below. We 
believe that without first understanding the test procedures, the 
numerical engine standards would not have the proper context.
(1) Engine Test Procedures
    The Phase 1 engine standards relied on the engine test procedures 
specified in 40 CFR part 1065. These procedures were previously used by 
EPA to regulate criteria pollutants such as NOX and PM, and 
few changes were needed to employ them for purposes of the Phase 1 
standards. The agencies are proposing significant changes to two areas 
for Phase 2: (1) cycle weighting; and (2) GEM inputs. (Note that EPA is 
also proposing some minor changes to the basic part 1065 test 
procedures, as described in Section XIII).
    The diesel (i.e., compression-ignition) engine test procedure 
relies on two separate engine test cycles. The first is the Heavy-duty 
Federal Test Procedure (Heavy-duty FTP) that includes transient 
operation typified by frequent accelerations and decelerations, similar 
to urban or suburban driving. The second is the Supplemental Engine 
Test (SET) which includes 13 steady-state test points. The SET was 
adopted by EPA to address highway cruise operation and other nominally 
steady-state operation. However, it is important to note that it was 
intended as a supplemental test cycle and not necessarily to replicate 
precisely any specific in-use operation.
    The gasoline (i.e., spark-ignition) engine test procedure relies on 
a single engine test cycle: a gasoline version of Heavy-duty FTP. The 
agencies are not proposing changes to the gasoline engine test 
procedures.
    It is worth noting that EPA sees great value in using the same test 
procedures for measuring GHG emissions as is used

[[Page 40192]]

for measuring criteria pollutants. From the manufacturers' perspective, 
using the same procedures minimizes their test burden. However, EPA 
sees additional benefits. First, as already noted in Section(b), 
requiring engine manufacturers to comply with both NOX and 
CO2 standards using the same test procedures discourages 
alternate calibrations that would trade NOX emissions 
against fuel consumption depending how the engine or vehicle is tested. 
Second, this approach leverages the work that went into developing the 
criteria pollutant cycles. Taken together, these factors support our 
decision to continue to rely on the 40 CFR part 1065 test procedures 
with only minor adjustments, such as those described in Section 
II.D.(1)(a). Nevertheless, EPA would consider more substantial changes 
if they were necessary to incentivize meaningful technology changes, 
similar to the changes being made to GEM for Phase 2 to address 
additional technologies.
(a) SET Cycle Weighting
    The SET cycle was adopted by EPA in 2000 and modified in 2005 from 
a discrete-mode test to a ramped-modal cycle to broadly cover the most 
significant part of the speed and torque map for heavy-duty engines, 
defined by three non-idle speeds and three relative torques. The low 
speed is often called the ``A speed'', the intermediate speed is often 
called the ``B speed'', and the high speed is often called the ``C 
speed.'' As is shown in Table II-1, the SET weights these three speeds 
at 23 percent, 39 percent, and 23 percent.

            Table II-1--SET Modes Weighting Factor in Phase 1
------------------------------------------------------------------------
                                                             Weighting
                      Speed, % load                          factor in
                                                           Phase 1  (%)
------------------------------------------------------------------------
Idle....................................................              15
A, 100..................................................               8
B, 50...................................................              10
B, 75...................................................              10
A, 50...................................................               5
A, 75...................................................               5
A, 25...................................................               5
B, 100..................................................               9
B, 25...................................................              10
C, 100..................................................               8
C, 25...................................................               5
C, 75...................................................               5
C, 50...................................................               5
Total...................................................             100
Total A Speed...........................................              23
Total B Speed...........................................              39
Total C Speed...........................................              23
------------------------------------------------------------------------

    The C speed is typically in the range of 1800 rpm for current HHD 
engine designs. However, it is becoming less common for engines to 
operate often in such a high speed in real world driving condition, and 
especially not during cruise vehicle speed between 55 and 65 mph. The 
agencies receive confidential business information from a few vehicle 
manufacturers that support this observation. Thus, although the current 
SET represents highway operation better than the FTP cycle, it is not 
an ideal cycle to represent future highway operation. Furthermore, 
given the recent trend configure drivetrains to operate engines at 
speeds down to a range of 1150-1200 rpm at vehicle speed of 65mph. This 
trend would make the typical highway engine speeds even further away 
from C speed.
    To address this issue, the agencies are proposing new weighting 
factors for the Phase 2 GHG and fuel consumption standards. The 
proposed new SET mode weightings move most of C weighting to ``A'' 
speed, as shown in Table II-2. It would also slightly reduce the 
weighting factor on the idle speed.
    The agencies request comment on the proposed reweighting.

       Table II-2--Proposed SET Modes Weighting Factor in Phase 2
------------------------------------------------------------------------
                                                             Proposed
                                                             weighting
                      Speed, % load                          factor in
                                                           Phase 2  (%)
------------------------------------------------------------------------
Idle....................................................              12
A, 100..................................................               9
B, 50...................................................              10
B, 75...................................................              10
A, 50...................................................              12
A, 75...................................................              12
A, 25...................................................              12
B, 100..................................................               9
B, 25...................................................               9
C, 100..................................................               2
C, 25...................................................               1
C, 75...................................................               1
C, 50...................................................               1
Total...................................................             100
Total A Speed...........................................              45
Total B Speed...........................................              38
Total C Speed...........................................               5
------------------------------------------------------------------------

(b) Measuring GEM Engine Inputs
    Although GEM does not apply directly to engine certification, 
implementing the Phase 2 GEM would impact engine manufacturers. To 
recognize the contribution of the engine in GEM the engine fuel map, 
full load torque curve and motoring torque curve have to be input into 
GEM. To insure the robustness of each of those inputs, a standard 
procedure has to be followed. Both the full load and motoring torque 
curve procedures are already defined in 40 CFR part 1065 for engine 
testing. However, the fuel mapping procedure being proposed would be 
new. The agencies have compared the proposed procedure against other 
accepted engine mapping procedures with a number of engines at various 
labs including EPA's NVFEL, Southwest Research Institute sponsored by 
the agencies, and Environment Canada's laboratory.\100\ The proposed 
procedure was selected because it proved to be accurate and repeatable, 
while limiting the test burden to create the fuel map. This proposed 
provision is consistent with NAS's recommendation (3.8).
---------------------------------------------------------------------------

    \100\ US EPA, ``Technical Research Workshop supporting EPA and 
NHTSA Phase 2 Standards for MD/HD Greenhouse Gas and Fuel 
Efficiency-- December 10 and 11, 2014,'' http://www.epa.gov/otaq/climate/regs-heavy-duty.htm.
---------------------------------------------------------------------------

    One important consideration is the need to correct measured fuel 
consumption rates for the carbon and energy content of the test fuel. 
For engine tests, we propose to continue the Phase 1 approach, which is 
specified in 40 CFR 1036.530. We propose a similar approach to GEM fuel 
maps in Phase 2.
    The agencies are proposing that engine manufacturers must certify 
fuel maps as part of their certification to the engine standards, and 
that they be required to provide those maps to vehicle manufacturers 
beginning with MY 2020.\101\ The one exception to this requirement 
would be for cases in which the engine manufacturer certifies based on 
powertrain testing, as described in Section (c). In such cases, engine 
manufacturers would not be required to also certify the otherwise 
applicable fuel maps. We are not proposing that vehicle manufacturers 
be allowed to develop their own fuel maps for engines they do not 
manufacture.
---------------------------------------------------------------------------

    \101\ Current normal vehicle manufacturing processes generally 
result in many vehicles being produced with prior model year 
engines. For example, we expect that some MY 2021 vehicles will be 
produced with MY 2020 engines. Thus, we are proposing to require 
engine manufacturers to begin providing fuel maps in 2020 so that 
vehicle manufacturers could run GEM to certify MY 2021 vehicles with 
MY 2020 engines.
---------------------------------------------------------------------------

    The current engine test procedures also require the development of 
regeneration emission rate and frequency factors to account for the 
emission changes for criteria pollutants during a regeneration event. 
In Phase 1, the agencies adopted provisions to exclude CO2 
emissions and fuel consumption due to regeneration. However, for Phase 
2, we propose to include CO2 emissions and fuel consumption 
due to regeneration over the FTP and RMC cycles as determined using the 
infrequently regenerating aftertreatment devices (IRAF) provisions in 
40 CFR 1065.680. We do not believe this would significantly impact the 
stringency of the proposed standards

[[Page 40193]]

because manufacturers have already made great progress in reducing the 
impact of regeneration emissions since 2007. Nevertheless, we believe 
it would be prudent to begin accounting for regeneration emissions to 
discourage manufacturers from adopting compliance strategies that would 
reverse this trend. We request comment on this requirement.
    We are not proposing, however, to include fuel consumption due to 
regeneration in the creation of the fuel map used in GEM for vehicle 
compliance. We believe that the proposed requirements for the duty-
cycle standards, along with market forces that already exist, would 
create sufficient incentives to reduce fuel consumption during 
regeneration over the entire fuel map.
(c) Engine Test Procedures for Replicating Powertrain Tests
    As described in Section II.B.(2)(b), the agencies are proposing a 
powertrain test option to quantify the benefits of CO2 
reducing powertrain technologies. These powertrain test results would 
then be used to override the engine and transmission simulation portion 
of GEM. The agencies are proposing to require that any manufacturer 
choosing to use this option also measure engine speed and engine torque 
during the powertrain test so that the engine's performance during the 
powertrain test could be replicated in a non-powertrain engine test 
cell. Subsequent engine testing would be conducted using the normal 
part 1065 engine test procedures, and g/hp-hr CO2 results 
would be compared to the levels the manufacturer reported during 
certification. Such testing would apply for both confirmatory and 
selective enforcement audit testing.
    Under the proposed regulations, engine manufacturers certifying 
powertrain performance (instead of or in addition to the multi-point 
fuel maps) would be held responsible for powertrain test results. If 
the engine manufacturer does not certify powertrain performance and 
instead certifies only the multi-point fuel maps, it would held 
responsible for fuel map performance rather than the powertrain test 
results. Engine manufacturers certifying both would be responsible for 
both.
(d) CO2 From Urea SCR Systems
    For diesel engines utilizing urea SCR emission control systems for 
NOX reduction, the agencies are proposing to allow 
correction of the final engine fuel map and powertrain duty cycle 
CO2 emission results to account for the contribution of 
CO2 from the urea injected into the exhaust. This urea could 
contribute up to 1 percent of the total CO2 emissions from 
the engine. Since current urea production methods use gaseous 
CO2 captured from the atmosphere (along with 
NH3), CO2 from urea consumption does not 
represent a net carbon emission. This adjustment is necessary so that 
fuel maps developed from CO2 measurements would be 
consistent with fuel maps from direct measurements of fuel flow rates. 
Thus, we are only proposing to allow this correction for emission tests 
where CO2 emissions are determined from direct measurement 
of CO2 and not from fuel flow measurement, which would not 
be impacted by CO2 from urea.
    We note that this correction would be voluntary for manufacturers, 
and expect that some manufacturers may determine that the correction is 
too small to be of concern. The agencies will use this correction with 
any engines for which the engine manufacturer applied the correction 
for its fuel maps during certification.
    We are not proposing this correction for engine test results with 
respect to the engine CO2 standards. Both the Phase 1 
standards and the proposed standards for CO2 from diesel 
engines are based on test results that included CO2 from 
urea. In other words, these standards are consistent with using a test 
procedure that does not correct for CO2 from urea. We 
request comment on whether it would be appropriate to allow this 
correction for the Phase 2 engine CO2 standards, but also 
adjust the standards to reflect the correction. At this time, we 
believe that reducing the numerical value of the CO2 
standards by 1 g/hp-hr would make the standards consistent with 
measurement that are corrected for CO2 from urea. However, 
we also request comment on the appropriateness of applying a 2 g/hp-hr 
adjustment should we determine it would better reflect the urea 
contribution for current engines.
(e) Potential Alternative Certification Approach
    In Section II.B.(2)(b), we explained that although GEM does not 
apply directly to engine certification, implementing the Phase 2 GEM 
would impact engine manufacturers by requiring that they measure engine 
fuel maps. In Section II.B.(2), the agencies noted that some 
stakeholders may have concerns about the proposed regulatory structure 
that would require engine manufacturers to provide detailed fuel 
consumption maps for GEM. Given such concerns, the agencies are 
requesting comment on an approach that could mitigate the concerns by 
allowing both vehicle and engine to use the same driving cycles for 
certification. The detailed description of this alternative 
certification approach can be seen in the draft RIA. We are requesting 
comment on allowing this approach as an option, or as a replacement to 
the proposed approach. Commenters supporting this approach should 
address possible impacts on the stringency of the proposed standards.
    This approach utilizes GEM with a default engine fuel map pre-
defined by the agency to run a number of pre-defined vehicle 
configurations over three certification cycles. Engine torque and speed 
profile would be obtained from the simulations, and would be used to 
specify engine dynamometer commands for engine testing. The results of 
this testing would be a CO2 map as function of the 
integrated work and the ratio of averaged engine speed (N) to averaged 
vehicle speed (V) defined as (N/V) over each certification cycle. In 
vehicle certification, vehicle manufacturers would run GEM with the to-
be-certified vehicle configuration and the agency default engine fuel 
map separately for each GEM cycle. Applying the total work and N/V 
resulted from the GEM simulations to the CO2 map obtained 
from engine tests would determine CO2 consumption for 
vehicle certification. For engine certification, we are considering 
allowing the engine to be certified based on one of the points 
conducted during engine alternative CO2 map tests mentioned 
above rather than based on the FTP and SET cycle testing.
(2) Proposed Engine Standards for CO2 and Fuel Consumption
    We are proposing to maintain the existing Phase 1 regulatory 
structure for engine standards, which had separate standards for spark-
ignition engines (such as gasoline engines) and compression-ignition 
engines (such as diesel engines), but we are proposing changes to how 
these standards would apply to natural gas fueled engines. As discussed 
in Section II.B.(2)(b), the agencies see important advantages to 
maintaining separate engines standards, such as improved compliance 
assurance and better control during transient engine operation.
    Phase 1 also applied different test cycles depending on whether the 
engine is used for tractors, vocational vehicles, or both, and we 
propose to continue this as well.\102\ We assume that CO2 at 
the

[[Page 40194]]

end of Phase 1 is the baseline of Phase 2. Table II-3 shows the Phase 1 
CO2 standards for diesel engines, which serve as the 
baseline for our analysis of the proposed Phase 2 standards.
---------------------------------------------------------------------------

    \102\ Engine classification is set forth in 40 CFR 1036.801. 
Spark-ignition means relating to a gasoline-fueled engine or any 
other type of engine with a spark plug (or other sparking device) 
and with operating characteristics similar to the Otto combustion 
cycle. However, engines that meet the definition of spark-ignition 
per 1036.801, but are regulated as diesel engines under 40 CFR part 
86 (for criteria pollutants) are treated as compression-ignition 
engines for GHG standards. Compression-ignition means relating to a 
type of reciprocating, internal-combustion engine that is not a 
spark-ignition engine, however, engines that meet the definition of 
compression-ignition per 1036.801, but are regulated as Otto-cycle 
engines under 40 CFR part 86 are treated as spark-ignition engines 
for GHG standards.

                                  Table II-3--Phase 2 Baseline CO2 Performance
                                                   (g/bhp-hr)
----------------------------------------------------------------------------------------------------------------
       LHDD-FTP               MHDD-FTP               HHDD-FTP               MHDD-SET              HHDD-SET
----------------------------------------------------------------------------------------------------------------
              576                    576                    555                    487                    460
----------------------------------------------------------------------------------------------------------------

    The gasoline engine baseline CO2 is 627 (g/bhp-hr). The 
agencies used the baseline engine to assess the potential of the 
technologies described in the following sections. As described below, 
the agencies are proposing new compression-ignition engine standards 
for Phase 2 that would require additional reductions in CO2 
emissions and fuel consumption beyond the baseline. However, as also 
described below in Section II.B.(2)(b), we are not proposing more 
stringent CO2 or fuel consumption standards for new heavy-
duty gasoline engines. Note, however, that we are projecting some small 
improvement in gasoline engine performance that would be recognized 
over the vehicle cycles.
    For heavy-heavy-duty diesel engines to be installed in Class 7 and 
8 combination tractors, the agencies are proposing the standards shown 
in Table II-4.\103\ The proposed MY 2027 standards for engines 
installed in tractors would require engine manufacturers to achieve, on 
average, a 4.2 percent reduction in fuel consumption and CO2 
emissions beyond the Phase 1 standard. We propose to adopt interim 
engine standards in MY 2021 and MY 2024 that would require diesel 
engine manufacturers to achieve, on average, 1.5 percent and 3.7 
percent reductions in fuel consumption and CO2 emissions, 
respectively.
---------------------------------------------------------------------------

    \103\ The agencies note that the CO2 and fuel 
consumption standards for Class 7 and 8 combination tractors do not 
cover gasoline or LHDD engines, as those are not used in Class 7 and 
8 combination tractors.

      Table II-4--Proposed Phase 2 Heavy-Duty Tractor Engine Standards for Engines\104\ Over the SET Cycle
----------------------------------------------------------------------------------------------------------------
                                                                                   Medium heavy-   Heavy heavy-
                 Model year                                Standard                 duty diesel     duty diesel
----------------------------------------------------------------------------------------------------------------
2021-2023..................................  CO2 (g/bhp-hr).....................        479             453
                                             Fuel Consumption (gallon/100 bhp-            4.7053          4.4499
                                              hr).
2024-2026..................................  CO2 (g/bhp-hr).....................        469             443
                                             Fuel Consumption (gallon/100 bhp-            4.6071          4.3517
                                              hr).
2027 and Later.............................  CO2 (g/bhp-hr).....................        466             441
                                             Fuel Consumption (gallon/100 bhp-            4.5776          4.3320
                                              hr).
----------------------------------------------------------------------------------------------------------------

    Forcompression-ignition engines fitted into vocational vehicles, 
the agencies are proposing MY 2027 standards that would require engine 
manufacturers to achieve, on average, a 4.0 percent reduction in fuel 
consumption and CO2 emissions beyond the Phase 1 standard. 
We propose to adopt interim engine standards in MY 2021 and MY 2024 
that would require diesel engine manufacturers to achieve, on average, 
2.0 percent and 3.5 percent reductions in fuel consumption and 
CO2 emissions, respectively.
---------------------------------------------------------------------------

    \104\ Tractor engine standards apply to all engines, without 
regard to the engine-cycle classification.
---------------------------------------------------------------------------

    Table II-5 presents the CO2 and fuel consumption 
standards the agencies propose for compression-ignition engines to be 
installed in vocational vehicles. The first set of standards would take 
effect with MY 2021, and the second set would take effect with MY 2024.

              Table II-5--Proposed Vocational Diesel Engine Standards Over the Heavy-Duty FTP Cycle
----------------------------------------------------------------------------------------------------------------
                                                                   Light heavy-    Medium heavy-   Heavy heavy-
             Model year                        Standard             duty diesel     duty diesel     duty diesel
----------------------------------------------------------------------------------------------------------------
2021-2023..........................  CO2 Standard (g/bhp-hr)....        565             565             544
                                     Fuel Consumption Standard            5.5501          5.5501          5.3438
                                      (gallon/100 bhp-hr).
2024-2026..........................  CO2 Standard (g/bhp-hr)....        556             556             536
                                     Fuel Consumption (gallon/            5.4617          5.4617          5.2652
                                      100 bhp-hr).
2027 and Later.....................  CO2 Standard (g/bhp-hr)....        553             553             533
                                     Fuel Consumption (gallon/            5.4322          5.4322          5.2358
                                      100 bhp-hr).
----------------------------------------------------------------------------------------------------------------

    Although both EPA and NHTSA are proposing to begin the Phase 2 
engine standards, EPA considered proposing Phase 2 standards that would 
begin before MY 2021--that is with less lead time. NHTSA is required by 
statute to

[[Page 40195]]

provide four models years of lead time, while EPA is required only to 
provide lead time ``necessary to permit the development and application 
of the requisite technology'' (CAA Section 202(a)(2)). However, as 
noted in Section I, lead time cannot be separated for other relevant 
factors such as costs, reliability, and stringency. Proposing these 
standards before 2021 could increase the risk of reliability issues in 
the early years. Given the limited number of engine models that each 
manufacturer produces, managing that many new standards would be 
problematic (i.e., new Phase 1 standards in 2017, new Phase 2 EPA 
standards in 2018, 2019, or 2020, new standards in 2021, 2024, and 
again in 2027). Considering these challenges, EPA determined that 
earlier model year standards would not be appropriate, especially given 
the value of harmonizing the NHTSA and EPA standards.
(a) Feasibility of the Diesel (Compression-Ignition) Engine Standards
    In this section, the agencies discuss our assessment of the 
feasibility of the proposed engine standards and the extent to which 
they would conform to our respective statutory authority and 
responsibilities. More details on the technologies discussed here can 
be found in the Draft RIA Chapter 2.3. The feasibility of these 
technologies is further discussed in draft RIA Chapter 2.7 for tractor 
and vocational vehicle engines. Note also, that the agencies are 
considering adopting engine standards with less lead time, and may do 
so in the Final Rules. These standards are discussed in Section (e).
    Based on the technology analysis described below, the agencies can 
project a technology path exists to allow manufacturers to meet the 
proposed final Phase 2 standards by 2027, as well as meeting the 
intermediate 2021 and 2024 standards. The agencies also project that 
manufacturers would be able to meet these standards at a reasonable 
cost and without adverse impacts on in-use reliability. Note that the 
agencies are still evaluating whether these same standards could be met 
sooner, as was analyzed in Alternative 4.
    In general, engine performance for CO2 emissions and 
fuel consumption can be improved by improving combustion and reducing 
energy losses. More specifically, the agencies have identified the 
following key areas where fuel efficiency can be improved:

 Combustion optimization
 Turbocharging system
 Engine friction and other parasitic losses
 Exhaust aftertreatment
 Engine breathing system
 Engine downsizing
 Waste heat recovery
 Transient control for vocational engines only

    The agencies are proposing to phase-in the standards from 2021 
through 2027 so that manufacturers could gradually introduce these 
technologies. For most of these improvements, the agencies project 
manufacturers could begin applying them to about 45-50 percent of their 
heavy-duty engines by 2021, 90-95 percent by 2024, and ultimately apply 
them to 100 percent of their heavy-duty engines by 2027. However, for 
some of these improvements (such as waste heat recovery and engine 
downsizing) we project lower application rates in the Phase 2 time 
frame. This phase-in structure is consistent with the normal manner in 
which manufacturers introduce new technology to manage limited R&D 
budgets and well as to allow them to work with fleets to fully evaluate 
in-use reliability before a technology is applied fleet-wide. The 
agencies believe the proposed phase-in schedule would allow 
manufacturers to complete these normal processes. As described in 
Section (e), the agencies are also requesting comment on whether 
manufacturers could complete these development steps more quickly so 
that they could meet these standards sooner.
    Based on our technology assessment described below, the proposed 
engine standards appear to be consistent with the agencies' respective 
statutory authorities. All of the technologies with high penetration 
rates above 50 percent have already been demonstrated to some extent in 
the field or in research laboratories, although some development work 
remains to be completed. We note that our feasibility analysis for 
these engine standards is not based on projecting 100 percent 
application for any technology until 2027. We believe that projecting 
less than 100 percent application is appropriate and gives us 
additional confidence that the interim standards would be feasible.
    Because this analysis considers reductions from engines meeting the 
Phase 1 standards, it assumes manufacturers would continue to include 
the same compliance margins as Phase 1. In other words, a manufacturer 
currently declaring FCLs 10 g/hp-hr above its measured emission rates 
(in order to account for production and test-to-test variability) would 
continue to do the same in Phase 2. We request comment on this 
assumption.
    The agencies have carefully considered the costs of applying these 
technologies, which are summarized in Section II.D.(2) (d). These costs 
appear to be reasonable on both a per engine basis, and when 
considering payback periods.\105\ The engine technologies are discussed 
in more detail below. Readers are encouraged to see the draft RIA 
Chapter 2 for additional details (and underlying references) about our 
feasibility analysis.
---------------------------------------------------------------------------

    \105\ See Section IX.M for additional information about payback 
periods.
---------------------------------------------------------------------------

(i) Combustion Optimization
    Although manufacturers are making significant improvements in 
combustion to meet the Phase 1 engine standards, the agencies project 
that even more improvement would be possible after 2018. For example, 
improvements to fuel injection systems would allow more flexible fuel 
injection capability with higher injection pressure, which can provide 
more opportunities to improve engine fuel efficiency. Further 
optimization of piston bowls and injector tips would also improve 
engine performance and fuel efficiency. We project that a reduction of 
up to 1.0 percent is feasible in the 2024 model year through the use of 
these technologies, although it would likely apply to only 95 percent 
of engines until 2027.
    Another important area of potential improvement is advanced engine 
control incorporating model based calibration to reduce losses of 
control during transient operation. Improvements in computing power and 
speed would make it possible to use much more sophisticated algorithms 
that are more predictive than today's controls. Because such controls 
are only beneficial during transient operation, they would reduce 
emission over the FTP cycle, and during in-use operation, they would 
not reduce emissions over the SET cycle. Thus the agencies are 
projecting model based control reductions only for vocational engines. 
Although this control concept is not currently available, we project 
model based controls achieving a 2 percent improvement in transient 
emissions could be in production for some engine models by 2021. By 
2027, we project over one-third of all vocational diesel engines would 
incorporate model-based controls.
(ii) Turbocharging System
    Many advanced turbocharger technologies can be potentially added

[[Page 40196]]

into production in the time frame between 2021 and 2027, and some of 
them are already in production, such as mechanical or electric turbo-
compound, more efficient variable geometry turbine, and Detroit 
Diesel's patented asymmetric turbocharger. A turbo compound system 
extracts energy from the exhaust to provide additional power. 
Mechanical turbo-compounding includes a power turbine located 
downstream of the turbine which in turn is connected to the crankshaft 
to supply additional power. On-highway demonstrations of this 
technology began in the early 1980s. It was used first in heavy duty 
production by Detroit Diesel for their DD15 and DD16 engines and 
reportedly provided a 3 to 5 percent fuel consumption reduction. 
Results are duty cycle dependent, and require significant time at high 
load to see a fuel efficiency improvement. Light load factor vehicles 
can expect little or no benefit. Volvo reports two to four percent fuel 
consumption improvement in line haul applications, which could be in 
production even by 2020.
(iii) Engine Friction and Parasitic Losses
    The friction associated with each moving part in an engine results 
in a small loss of engine power. For example, frictional losses occur 
at bearings, in the valvetrain, and at the piston-cylinder interface. 
Taken together such losses represent a large fraction of all energy 
lost in an engine. For Phase 1, the agencies projected a 1-2 percent 
reduction in fuel consumption due to friction reduction. However, new 
information leads us to project that an additional 1.4 percent 
reduction would be possible for some engines by 2021 and all engines by 
2027. These reductions would be possible due to improvements in bearing 
materials, lubricants, and new accessory designs such as variable-speed 
pumps.
(iv) Aftertreatment Optimization
    All diesel engines manufacturers are already using diesel 
particulate filter (DPF) to reduce particulate matter (PM) and 
selective catalytic reduction (SCR) to reduce NOX emissions. 
The agencies see two areas in which improved aftertreatment systems can 
also result in lower fuel consumption. First, increased SCR efficiency 
could allow re-optimization of combustion for better fuel consumption 
because the SCR would be capable of reducing higher engine-out 
NOX emissions. Second, improved designs could reduce 
backpressure on the engine to lower pumping losses. The agencies 
project the combined impact of such improvements could be 0.6 percent 
or more.
(v) Engine Breathing System
    Various high efficiency air handling (for both intake air and 
exhaust) processes could be produced in the 2020 and 2024 time frame. 
To maximize the efficiency of such processes, induction systems may be 
improved by manufacturing more efficiently designed flow paths 
(including those associated with air cleaners, chambers, conduit, mass 
air flow sensors and intake manifolds) and by designing such systems 
for improved thermal control. Improved turbocharging and air handling 
systems would likely include higher efficiency EGR systems and 
intercoolers that reduce frictional pressure loss while maximizing the 
ability to thermally control induction air and EGR. EGR systems that 
often rely upon an adverse pressure gradient (exhaust manifold 
pressures greater than intake manifold pressures) must be reconsidered 
and their adverse pressure gradients minimized. Other components that 
offer opportunities for improved flow efficiency include cylinder 
heads, ports and exhaust manifolds to further reduce pumping losses by 
about 1 percent.
(vi) Engine Downsizing
    Proper sizing of an engine is an important component of optimizing 
a vehicle for best fuel consumption. This Phase 2 rule would improve 
overall vehicle efficiency, which would result in a drop in the vehicle 
power demand for most operation. This drop moves the vehicle operating 
points down to a lower load zone, which can move the engine away from 
the sweet spot. Engine downsizing combined with engine downspeeding can 
allow the engine to move back to higher loads and lower speed zone, 
thus achieving slightly better fuel economy in the real world. However, 
because of the way engines are tested, little of the benefit of engine 
downsizing would be detected during engine testing (if power density 
remains the same) because the engine test cycles are normalized based 
on the full torque curve. Thus the current engine test is not the best 
way to measure the true effectiveness of engine downsizing. 
Nevertheless, we project that some small benefit would be measured over 
the engine test cycles--perhaps up to a one-quarter percent improvement 
in fuel consumption. Note that a bigger benefit would be observed 
during GEM simulation, better reflecting real world improvements. This 
is factored into the vehicle standards. Thus, the agencies see no 
reason to fundamentally revise the engine test procedure at this time.
(vii) Waste Heat Recovery
    More than 40 percent of all energy loss in an engine is lost as 
heat to the exhaust and engine coolant. For many years, manufacturers 
have been using turbochargers to convert some of the waste heat in the 
exhaust into usable mechanical power than is used to compress the 
intake air. Manufacturers have also been working to use a Rankine 
cycle-based system to extract additional heat energy from the engine. 
Such systems are often called waste heat recovery (WHR) systems. The 
possible sources of energy include the exhaust, recirculated exhaust 
gases, compressed charge air, and engine coolant. The basic approach 
with WHR is to use waste heat from one or more of these sources to 
evaporate a working fluid, which is passed through a turbine or 
equivalent expander to create mechanical or electrical power, then re-
condensed.
    Prior to the Phase 1 Final Rule, the NAS estimated the potential 
for WHR to reduce fuel consumption by up to 10 percent.\106\ However, 
the agencies do not believe such levels would be achievable within the 
Phase 2 time frame. There currently are no commercially available WHR 
systems for diesel engines, although research prototype systems are 
being tested by some manufacturers. The agencies believe it is likely a 
commercially-viable WHR capable of reducing fuel consumption by over 
three percent would be available in the 2021 to 2024 time frame. Cost 
and complexity may remain high enough to limit the use of such systems 
in this time frame. Moreover, packaging constraints and transient 
response challenges would limit the application of WHR systems to line-
haul tractors. Refer to RIA Chapter 2 for a detailed description of 
these systems and their applicability. The agencies project that WHR 
recovery could be used on 1 percent of all tractor engines by 2021, on 
5 percent by 2024, and 15 percent by 2027.
---------------------------------------------------------------------------

    \106\ See 2010 NAS Report, page 57.
---------------------------------------------------------------------------

    The net cost and effectiveness of future WHR systems would depend 
on the sources of waste heat. Systems that extract heat from EGR gases 
may provide the side benefit of reducing the size of EGR coolers or 
eliminating them altogether. To the extent that WHR systems use exhaust 
heat, they would increase the overall cooling system heat rejection 
requirement and likely require larger radiators. This could have 
negative impacts on cooling fan power

[[Page 40197]]

needs and vehicle aerodynamics. Limited engine compartment space under 
hood could leave insufficient room for additional radiator size 
increasing. On the other hand, WHR systems that extract heat from the 
engine coolant, could actually improve overall cooling.
(viii) Technology Packages for Diesel Engines Installed in Tractors
    Typical technology packaged for diesel engines installed in 
tractors basically includes most technologies mentioned above, which 
includes combustion optimization, turbocharging system, engine friction 
and other parasitic losses, exhaust aftertreatment, engine breathing 
system, and engine downsizing. Depending on the technology maturity of 
WHR and market demands, a small number of tractors could install waste 
heat recovery device with Rankine cycle technology. During the 
stringency development, the agencies received strong support from 
various stakeholders, where they graciously provided many confidential 
business information (CBI) including both technology reduction 
potentials and estimated market penetrations. Combining those CBI data 
with the agencies' engineering judgment, Table II-4 lists those 
potential technologies together with the agencies' estimated market 
penetration for tractor engine. Those reduction values shown as ``SET 
reduction'' are relative to Phase 1 engine, which is shown in Table II-
6. It should be pointed out that the stringency in Table II-6 are 
developed based on the proposed SET reweighting factors l shown in 
Table II-2. The agencies welcome comment on the market penetration 
rates listed below.

                         Table II-6--Projected Tractor Engine Technologies and Reduction
----------------------------------------------------------------------------------------------------------------
                                                   SET weighted       Market          Market          Market
                    SET mode                       reduction (%)    penetration     penetration     penetration
                                                     2020-2027       (2021) %        (2024) %        (2027) %
----------------------------------------------------------------------------------------------------------------
Turbo compound with clutch......................             1.8               5              10              10
WHR (Rankine cycle).............................             3.6               1               5              15
Parasitic/Friction (Cyl Kits, pumps, FIE),                   1.4              45              95             100
 lubrication....................................
Aftertreatment (lower dP).......................             0.6              45              95             100
EGR/Intake & exhaust manifolds/Turbo/VVT/Ports..             1.1              45              95             100
Combustion/FI/Control...........................             1.1              45              95             100
Downsizing......................................             0.3              10              20              30
Weighted reduction (%)..........................  ..............             1.5             3.7             4.2
----------------------------------------------------------------------------------------------------------------

(ix) Technology Packages for Diesel Engines Installed in Vocational 
Vehicles
    For compression-ignition engines fitted into vocational vehicles, 
the agencies are proposing MY 2021 standards that would require engine 
manufacturers to achieve, on average, a 2.0 percent reduction in fuel 
consumption and CO2 emissions beyond the baseline that is 
the Phase 1 standard. Beginning in MY 2024, the agencies are proposing 
engine standards that would require diesel engine manufacturers to 
achieve, on average, a 3.5 percent reduction in fuel consumption and 
CO2 emissions beyond the Phase 1 baseline standards for all 
diesel engines including LHD, MHD, and HHD. The agencies are proposing 
these standards based on the performance of reduced parasitics and 
friction, improved aftertreatment, combustion optimization, 
superchargers with VGT and bypass, model-based controls, improved EGR 
cooling/transport, and variable valve timing (only in LHD and MHD 
engines). The percent reduction for the MY2021, MY2024, and MY2027 
standards is based on the combination of technology effectiveness and 
market adoption rate projected.
    Most of the potential engine related technologies discussed 
previously can be applied here. However, neither the waste heat 
technologies with the Rankine cycle concept nor turbo-compound would be 
applied into vocational sector due to the inefficient use of waste heat 
energy with duty cycles and applications with more transient operation 
than highway operation. Given the projected cost and complexity of such 
systems, we believe that for the Phase 2 time frame manufacturers will 
focus their development work on tractor applications (which would have 
better payback for operators) rather than vocational applications. In 
addition, the benefits due to engine downsizing, which can be seen in 
tractor engines, may not be clearly seen in vocational sector, again 
because this control technology produces few benefits in transient 
operation.
    One of the most effective technologies for vocational engines is 
the optimization of transient control. It would be expected that more 
advanced transient control including different levels of model based 
control and neural network control package could provide substantial 
benefits in vocational engines due to the extensive transient operation 
of these vehicles. For this technology, the use of the FTP cycle would 
drive engine manufacturers to invest more in transient control to 
improve engine efficiency. Other effective technologies would be 
parasitic/friction reduction, as well as improvements to combustion, 
air handling systems, turbochargers, and aftertreatment systems. Table 
II-7 below lists those potential technologies together with the 
agencies' projected market penetration for vocational engines. Again, 
similar to tractor engine, the technology reduction and market 
penetration are estimated by combining the CBI data together with the 
agencies' engineering judgment. Those reduction values shown as ``FTP 
reduction'' are relative to a Phase 2 baseline engine, which is shown 
in Table II-3. The weighted reductions combine the emission reduction 
values weighted by the market penetration of each technology).

[[Page 40198]]



                       Table II-7--Projected Vocational Engine Technologies and Reduction
----------------------------------------------------------------------------------------------------------------
                                                   GHG emissions      Market          Market          Market
                   Technology                     reduction 2020-   penetration     penetration     penetration
                                                      2027 %          2021 %          2024 %          2027 %
----------------------------------------------------------------------------------------------------------------
Model based control.............................             2.0              25              30              40
Parasitic/Friction..............................             1.5              60              90             100
EGR/Air/VVT/Turbo...............................             1.0              50              90             100
Improved AT.....................................             0.5              50              90             100
Combustion Optimization.........................             1.0              50              90             100
Weighted reduction (%)-L/M/HHD..................  ..............             2.0             3.5             4.0
----------------------------------------------------------------------------------------------------------------

(x) Summary of the Agencies' Analysis of the Feasibility of the 
Proposed Diesel Engine Standards
    The proposed HD Phase 2 standards are based on adoption rates for 
technologies that the agencies regard, subject to consideration of 
public comment, as the maximum feasible for purposes of EISA Section 
32902(k) and appropriate under CAA Section 202(a) for the reasons given 
above. The agencies believe these technologies can be adopted at the 
estimated rates for these standards within the lead time provided, as 
discussed in draft RIA Chapter 2. The 2021 and 2024 MY standards are 
phase-in standards on the path to the 2027 MY standards and were 
developed using less aggressive application rates and therefore have 
lower technology package costs than the 2027 MY standards.
    As described in Section II.D.(2)(d) below, the cost of the proposed 
standards is estimated to range from $270 to $1,698 per engine. This is 
slightly higher than the costs for Phase 1, which were estimated to be 
$234 to $1,091 per engine. Although the agencies did not separately 
determine fuel savings or emission reductions due to the engine 
standards apart from the vehicle program, it is expected that the fuel 
savings would be significantly larger than these costs, and the 
emission reductions would be roughly proportional to the technology 
costs when compared to the corresponding vehicle program reductions and 
costs. Thus, we regard these standards as cost-effective. This is true 
even without considering payback period. The proposed phase-in 2021 and 
2024 MY standards are less stringent and less costly than the proposed 
2027 MY standards. Given that the agencies believe the proposed 
standards are technologically feasible, are highly cost effective, and 
highly cost effective when accounting for the fuel savings, and have no 
apparent adverse potential impacts (e.g., there are no projected 
negative impacts on safety or vehicle utility), the proposed standards 
appear to represent a reasonable choice under Section 202(a) of the CAA 
and the maximum feasible under NHTSA's EISA authority at 49 U.S.C. 
32902(k)(2).
(b) Basis for Continuing the Phase 1 Spark-Ignited Engine Standard
    Today most SI-powered vocational vehicles are sold as incomplete 
vehicles by a vertically integrated chassis manufacturer, where the 
incomplete chassis shares most of the same technology as equivalent 
complete pickups or vans, including the powertrain. The number of such 
incomplete SI-powered vehicles is small compared to the number of 
completes. Another, even less common way that SI-powered vocational 
vehicles are built is by a non-integrated chassis manufacturer 
purchasing an engine from a company that also produces complete and/or 
incomplete HD pickup trucks and vans. The resulting market structure 
leads manufacturers of heavy-duty SI engines to have little market 
incentive to develop separate technology for vocational engines that 
are engine-certified. Moreover, the agencies have not identified a 
single SI engine technology that we believe belongs on engine-certified 
vocational engines that we do not also project to be used on complete 
heavy-duty pickups and vans.
    In light of this market structure, when the agencies considered the 
feasibility of more stringent Phase 2 standards for SI vocational 
engines, we identified the following key questions:
    1. Will there be technologies available that could reduce in-use 
emissions from vocational SI engines?
    2. Would these technologies be applied to complete vehicles and 
carried-over to engine certified engines without a new standard?
    3. Would these technologies be applied to meet the vehicle-based 
standards described in Section V?
    4. What are the drawbacks associated with setting a technology-
forcing Phase 2 standard for SI engines?
    With respect to the first and second questions, as noted in Chapter 
2.6 of the draft RIA, the agencies have identified improved lubricants, 
friction reduction, and cylinder deactivation as technologies that 
could potentially reduce in-use emissions from vocational engines; and 
the agencies have further determined that to the extent these 
technologies would be viable for complete vehicles, they would also be 
applied to engine-certified engines. Nevertheless, significant 
uncertainty remains about how much benefit would be provided by these 
technologies. It is possible that the combined impact of these 
technologies would be one percent or less. With respect to the third 
question, we believe that to the extent these technologies are viable 
and effective, they would be applied to meet the vehicle-based 
standards for vocational vehicles.
    At this time, it appears the fourth question regarding drawbacks is 
the most important. The agencies could propose a technology forcing 
standard for vocational SI engines based on a projection of each of 
these technologies being effective for these engines. However, as 
already noted in Section I, the agencies see value in setting the 
standards at levels that would not require every projected technology 
to work as projected. Effectively requiring technologies to match our 
current projections would create the risk that the standards would not 
be feasible if even a single one of technologies failed to match our 
projections. This risk is amplified for SI engines because of the very 
limited product offerings, which provide far fewer opportunities for 
averaging than exist for CI engines. Given the relatively small 
improvement projected, and the likelihood that most or all of this 
improvement would result anyway from the complete pickup and van 
standards and the vocational vehicle-based standards, we do not believe 
such risk is justified or needed. The approach the agencies are 
proposing accomplishes the same objective without the attendant

[[Page 40199]]

potential risk. With this approach, the Phase 1 SI engine standard for 
these engines would remain in place, and engine improvements would be 
reflected in the stringency of the vehicle standard for the vehicle in 
which the engine would be installed. Nevertheless, we request comment 
on the merits of adopting a more stringent SI engine standard in the 
2024 to 2027 time frame, including comment on technologies, adoption 
rates, and effectiveness over the engine cycle that could support 
adoption of a more stringent standard. Please see Section V.C of this 
preamble for a description of the SI engine technologies that have been 
considered in developing the proposed vocational vehicle standards. 
Please see Section VI.C of this preamble for a description of the SI 
engine technologies that have been considered in developing the 
proposed HD pickup truck and van standards.
(c) Engine Improvements Projected for Vehicles over the GEM Duty Cycles
    Because we are proposing that tractor and vocational vehicle 
manufacturers represent their vehicles' actual engines in GEM for 
vehicle certification, the agencies aligned our engine technology 
effectiveness assessments for both the separate engine standards and 
the tractor and vocational vehicle standards for each of the regulatory 
alternatives considered. This was an important step because we are 
proposing to recognize the same engine technologies in both the 
separate engine standards and the vehicle standards, which each have 
different test procedures for demonstrating compliance. As explained 
earlier in Section II. D. (1), compliance with the tractor separate 
engine standards is determined from a composite of the Supplemental 
Engine Test (SET) procedure's 13 steady-state operating points. 
Compliance with the vocational vehicle separate engine standards is 
determined over the Federal Test Procedure's (FTP) transient engine 
duty cycle. In contrast, compliance with the vehicle standards is 
determined using GEM, which calculates composite results over a 
combination of 55 mph and 65 mph steady-state vehicle cycles and the 
ARB Transient vehicle cycle. Note that we are also proposing a new 
workday idle cycle for vocational vehicles. Each of these duty cycles 
emphasizes different engine operating points; therefore, they can each 
recognize certain technologies differently.
    Our first step in aligning our engine technology assessment at both 
the engine and vehicle levels was to start with an analysis of how we 
project each technology to impact performance at each of the 13 
individual test points of the SET steady-state engine duty cycle. For 
example, engine friction reduction technology would be expected to have 
the greatest impact at the highest engine speeds, where frictional 
energy losses are the greatest. As another example, turbocharger 
technology is generally optimized for best efficiency at steady-state 
cruise vehicle speed. For an engine this is near its lower peak-torque 
speed and at a moderately high load that still offers sufficient torque 
reserve to climb modest road grades without frequent transmission gear 
shifting. The agencies also considered the combination of certain 
technologies causing synergies and dis-synergies with respect to engine 
efficiency at each of these test points. See RIA Chapter 2 for further 
details.
    Next we estimated unique brake-specific fuel consumption values for 
each of the 13 SET test points for two hypothetical MY2018 tractor 
engines that would be compliant with the Phase 1 standards. These were 
a 15 liter displacement 455 horsepower engine and an 11 liter 350 
horsepower engine. We then added technologies to these engines that we 
determined were feasible for MY2021, MY2024, and MY 2027, and we 
determined unique improvements at each of the 13 SET points. We then 
calculated composite SET values for these hypothetical engines and 
determined the SET improvements that we could use to propose more 
stringent separate tractor engine standards for MY2021, MY2024, and MY 
2027.
    To align our engine technology analysis for vehicles to the SET 
engine analysis described above, we then fit a surface equation through 
each engine's SET points versus engine speed and load to approximate 
their analogous fuel maps that would represent these same engines in 
GEM. Because the 13 SET test points do not fully cover an engine's wide 
range of possible operation, we also determined improvements for an 
additional 6 points of engine operation to improve the creation of GEM 
fuel maps for these engines. Then for each of these 8 tractor engines 
(two each for MY2018, MY2021, MY2024, and MY2027) we ran GEM 
simulations to represent low-, mid-, and high-roof sleeper cabs and 
low-, mid-, and high-roof day cabs. Class 8 tractors were assumed for 
the 455 horsepower engine and Class 7 tractors (day cabs only) were 
assumed for the 350 horsepower engine. Each GEM simulation calculated 
results for the 55 mph, 65 mph, and ARB Transient cycles, as well as 
the composite GEM value associated with each of the tractor types. 
After factoring in our Alternative 3 projected market penetrations of 
the engine technologies, we then compared the percent improvements that 
the same sets of engine technology caused over the separate engines' 
SET composites and the various vehicles' GEM composites. Compared to 
their respective MY2018 baseline engines, the two engines of different 
horsepower showed the same percent improvements. All of the tractor cab 
types showed nearly the same relative improvements too. For example, 
for the MY2021 Alternative 3 engine technology package in a high roof 
sleeper tractor, the SET engine composites showed a 1.5 percent 
improvement and the GEM composites a 1.6 percent improvement. For the 
MY2024 Alternative 3 engine technology packages, the SET engine 
composites showed a 3.7 percent improvement and the GEM composites a 
3.7 percent improvement. For MY2027 Alternative 3 engine technology 
packages, the SET engine composites showed a 4.2 percent improvement 
and the GEM composites a 4.2 percent improvement. We therefore 
concluded that tractor engine technologies will improve engines and 
tractors proportionally, even though the separate engine and vehicle 
certification test procedures have different duty cycles.
    We then repeated this same process for the FTP engine transient 
cycle and the GEM vocational vehicle types. For the vocational engine 
analysis we investigated four engines: 15 liter displacement engine at 
455 horsepower rating, 11 liter displacement engine at 345 horsepower 
rating, a 7 liter displacement engine at a 200 horsepower rating and a 
270 horsepower rating. These engines were then used in GEM over the 
light-heavy, medium-heavy, and heavy-heavy vocational vehicle 
configurations. Because the technologies were assumed to impact each 
point of the FTP in the same way, the results for all engines and 
vehicles were 2.0 percent improvement in MY2021, 3.5 percent 
improvement in MY2024, and 4.0 percent improvement in MY2027. 
Therefore, we arrived at the same conclusion that vocational vehicle 
engine technologies are recognized at the same percent improvement over 
the FTP as the GEM cycles. We request comment on our approach to arrive 
at this conclusion.
(d) Engine Technology Package Costs for Tractor and Vocational Engines 
(and Vehicles)
    As described in Chapters 2 and 7 of the draft RIA, the agencies 
estimated costs for each of the engines technologies discussed here. 
All costs

[[Page 40200]]

are presented relative to engines projected to comply with the model 
year 2017 standards--i.e., relative to our baseline engines. Note that 
we are not presenting any costs for gasoline engines (SI engines) 
because we are not proposing to change the standards.
    Our engine cost estimates include a separate analysis of the 
incremental part costs, research and development activities, and 
additional equipment. Our general approach used elsewhere in this 
action (for HD pickup trucks, gasoline engines, Class 7 and 8 tractors, 
and Class 2b-8 vocational vehicles) estimates a direct manufacturing 
cost for a part and marks it up based on a factor to account for 
indirect costs. See also 75 FR 25376. We believe that approach is 
appropriate when compliance with proposed standards is achieved 
generally by installing new parts and systems purchased from a 
supplier. In such a case, the supplier is conducting the bulk of the 
research and development on the new parts and systems and including 
those costs in the purchase price paid by the original equipment 
manufacturer. The indirect costs incurred by the original equipment 
manufacturer need not include much cost to cover research and 
development since the bulk of that effort is already done. For the MHD 
and HHD diesel engine segment, however, the agencies believe that OEMs 
will incur costs not associated with the purchase of parts or systems 
from suppliers or even the production of the parts and systems, but 
rather the development of the new technology by the original equipment 
manufacturer itself. Therefore, the agencies have directly estimated 
additional indirect costs to account for these development costs. The 
agencies used the same approach in the Phase 1 HD rule. EPA commonly 
uses this approach in cases where significant investments in research 
and development can lead to an emission control approach that requires 
no new hardware. For example, combustion optimization may significantly 
reduce emissions and cost a manufacturer millions of dollars to develop 
but would lead to an engine that is no more expensive to produce. Using 
a bill of materials approach would suggest that the cost of the 
emissions control was zero reflecting no new hardware and ignoring the 
millions of dollars spent to develop the improved combustion system. 
Details of the cost analysis are included in the draft RIA Chapter 2. 
To reiterate, we have used this different approach because the MHD and 
HHD diesel engines are expected to comply in part via technology 
changes that are not reflected in new hardware but rather reflect 
knowledge gained through laboratory and real world testing that allows 
for improvements in control system calibrations--changes that are more 
difficult to reflect through direct costs with indirect cost 
multipliers. Note that these engines are also expected to incur new 
hardware costs as shown in Table II-8 through Table II-11. EPA also 
developed the incremental piece cost for the components to meet each of 
the 2021 and 2024 standards. The costs shown in Table II-12 include a 
low complexity ICM of 1.15 and assume the flat-portion of the learning 
curve is applicable to each technology.
(i) Tractor Engine Package Costs

    Table II-8--Proposed MY2021 Tractor Diesel Engine Component Costs
      Inclusive of Indirect Cost Markups and Adoption Rates (2012$)
------------------------------------------------------------------------
                                             Medium HD       Heavy HD
------------------------------------------------------------------------
Aftertreatment system (improved                       $7              $7
 effectiveness SCR, dosing, DPF)........
Valve Actuation.........................              82              82
Cylinder Head (flow optimized, increased               3               3
 firing pressure, improved thermal
 management)............................
Turbocharger (improved efficiency)......               9               9
Turbo Compounding.......................              50              50
EGR Cooler (improved efficiency)........               2               2
Water Pump (optimized, variable vane,                 43              43
 variable speed)........................
Oil Pump (optimized)....................               2               2
Fuel Pump (higher working pressure,                    2               2
 increased efficiency, improved pressure
 regulation)............................
Fuel Rail (higher working pressure).....               5               5
Fuel Injector (optimized, improved                     5               5
 multiple event control, higher working
 pressure)..............................
Piston (reduced friction skirt, ring and               1               1
 pin)...................................
Valvetrain (reduced friction, roller                  39              39
 tappet)................................
Waste Heat Recovery.....................             105             105
``Right sized'' engine..................             -40             -40
                                         -------------------------------
    Total...............................             314             314
------------------------------------------------------------------------
Note: ``Right sized'' diesel engine is a smaller, less costly engine
  than the engine it replaces.


    Table II-9--Proposed MY2024 Tractor Diesel Engine Component Costs
      Inclusive of Indirect Cost Markups and Adoption Rates (2012$)
------------------------------------------------------------------------
                                             Medium HD       Heavy HD
------------------------------------------------------------------------
Aftertreatment system (improved                      $14             $14
 effectiveness SCR, dosing, DPF)........
Valve Actuation.........................             166             166
Cylinder Head (flow optimized, increased               6               6
 firing pressure, improved thermal
 management)............................
Turbocharger (improved efficiency)......              17              17
Turbo Compounding.......................              92              92
EGR Cooler (improved efficiency)........               3               3
Water Pump (optimized, variable vane,                 84              84
 variable speed)........................
Oil Pump (optimized)....................               4               4
Fuel Pump (higher working pressure,                    4               4
 increased efficiency, improved pressure
 regulation)............................
Fuel Rail (higher working pressure).....               9               9
Fuel Injector (optimized, improved                    10              10
 multiple event control, higher working
 pressure)..............................
Piston (reduced friction skirt, ring and               3               3
 pin)...................................
Valvetrain (reduced friction, roller                  75              75
 tappet)................................

[[Page 40201]]

 
Waste Heat Recovery.....................             502             502
``Right sized'' engine..................             -85             -85
                                         -------------------------------
    Total...............................             904             904
------------------------------------------------------------------------
Note: ``Right sized'' diesel engine is a smaller, less costly engine
  than the engine it replaces.


   Table II-10--Proposed MY2027 Tractor Diesel Engine Component Costs
      Inclusive of Indirect Cost Markups and Adoption Rates (2012$)
------------------------------------------------------------------------
                                             Medium HD       Heavy HD
------------------------------------------------------------------------
Aftertreatment system (improved                      $14             $14
 effectiveness SCR, dosing, DPF)........
Valve Actuation.........................             169             169
Cylinder Head (flow optimized, increased               6               6
 firing pressure, improved thermal
 management)............................
Turbocharger (improved efficiency)......              17              17
Turbo Compounding.......................              87              87
EGR Cooler (improved efficiency)........               3               3
Water Pump (optimized, variable vane,                 84              84
 variable speed)........................
Oil Pump (optimized)....................               4               4
Fuel Pump (higher working pressure,                    4               4
 increased efficiency, improved pressure
 regulation)............................
Fuel Rail (higher working pressure).....               9               9
Fuel Injector (optimized, improved                    10              10
 multiple event control, higher working
 pressure)..............................
Piston (reduced friction skirt, ring and               3               3
 pin)...................................
Valvetrain (reduced friction, roller                  75              75
 tappet)................................
Waste Heat Recovery.....................           1,340           1,340
``Right sized'' engine..................            -127            -127
                                         -------------------------------
Total...................................           1,698           1,698
------------------------------------------------------------------------
Note: ``Right sized'' diesel engine is a smaller, less costly engine
  than the engine it replaces.

(ii) Vocational Diesel Engine Package Costs

  Table II-11--Proposed MY2021 Vocational Diesel Engine Component Costs Inclusive of Indirect Cost Markups and
                                             Adoption Rates (2012$)
----------------------------------------------------------------------------------------------------------------
                                                                     Light HD        Medium HD       Heavy HD
----------------------------------------------------------------------------------------------------------------
Aftertreatment system (improved effectiveness SCR, dosing, DPF).              $8              $8              $8
Valve Actuation.................................................              91              91              91
Cylinder Head (flow optimized, increased firing pressure,                      6               3               3
 improved thermal management)...................................
Turbocharger (improved efficiency)..............................              10              10              10
EGR Cooler (improved efficiency)................................               2               2               2
Water Pump (optimized, variable vane, variable speed)...........              57              57              57
Oil Pump (optimized)............................................               3               3               3
Fuel Pump (higher working pressure, increased efficiency,                      3               3               3
 improved pressure regulation)..................................
Fuel Rail (higher working pressure).............................               7               6               6
Fuel Injector (optimized, improved multiple event control,                     8               6               6
 higher working pressure).......................................
Piston (reduced friction skirt, ring and pin)...................               1               1               1
Valvetrain (reduced friction, roller tappet)....................              69              52              52
Model Based Controls............................................              28              28              28
                                                                 -----------------------------------------------
    Total.......................................................             293             270             270
----------------------------------------------------------------------------------------------------------------


  Table II-12--Proposed MY2024 Vocational Diesel Engine Component Costs Inclusive of Indirect Cost Markups and
                                             Adoption Rates (2012$)
----------------------------------------------------------------------------------------------------------------
                                                                     Light HD        Medium HD       Heavy HD
----------------------------------------------------------------------------------------------------------------
Aftertreatment system (improved effectiveness SCR, dosing, DPF).             $13             $13             $13
Valve Actuation.................................................             157             157             157
Cylinder Head (flow optimized, increased firing pressure,                     10               6               6
 improved thermal management)...................................
Turbocharger (improved efficiency)..............................              16              16              16
EGR Cooler (improved efficiency)................................               3               3               3
Water Pump (optimized, variable vane, variable speed)...........              79              79              79
Oil Pump (optimized)............................................               4               4               4

[[Page 40202]]

 
Fuel Pump (higher working pressure, increased efficiency,                      4               4               4
 improved pressure regulation)..................................
Fuel Rail (higher working pressure).............................              10               9               9
Fuel Injector (optimized, improved multiple event control,                    13              10              10
 higher working pressure).......................................
Piston (reduced friction skirt, ring and pin)...................               2               2               2
Valvetrain (reduced friction, roller tappet)....................              95              71              71
Model Based Controls............................................              31              31              31
                                                                 -----------------------------------------------
    Total.......................................................             437             405             405
----------------------------------------------------------------------------------------------------------------


  Table II-13--Proposed MY2027 Vocational Diesel Engine Component Costs Inclusive of Indirect Cost Markups and
                                             Adoption Rates (2012$)
----------------------------------------------------------------------------------------------------------------
                                                                     Light HD        Medium HD       Heavy HD
----------------------------------------------------------------------------------------------------------------
Aftertreatment system (improved effectiveness SCR, dosing, DPF).             $14             $14             $14
Valve Actuation.................................................             169             169             169
Cylinder Head (flow optimized, increased firing pressure,                     10               6               6
 improved thermal management)...................................
Turbocharger (improved efficiency)..............................              17              17              17
EGR Cooler (improved efficiency)................................               3               3               3
Water Pump (optimized, variable vane, variable speed)...........              84              84              84
Oil Pump (optimized)............................................               4               4               4
Fuel Pump (higher working pressure, increased efficiency,                      4               4               4
 improved pressure regulation)..................................
Fuel Rail (higher working pressure).............................              11               9               9
Fuel Injector (optimized, improved multiple event control,                    13              10              10
 higher working pressure).......................................
Piston (reduced friction skirt, ring and pin)...................               3               3               3
Valvetrain (reduced friction, roller tappet)....................             100              75              75
Model Based Controls............................................              39              39              39
                                                                 -----------------------------------------------
    Total.......................................................             471             437             437
----------------------------------------------------------------------------------------------------------------

(e) Feasibility of Phasing In the CO2 and Fuel Consumption 
Standards Sooner
    The agencies are requesting comment on accelerated standards for 
diesel engines that would achieve the same reductions as the proposed 
standards, but with less lead time. Table II-14 and Table II-15 below 
show a technology path that the agencies project could be used to 
achieve the reductions that would be required within the lead time 
allowed by the alternative standards. As discussed in Sections I and X, 
the agencies are proposing to fully phase in these standards through 
2027. The agencies believe that standards that fully phase in through 
2024 have the potential to be the maximum feasible and appropriate 
option. However, based on the evidence currently before the agencies, 
we have outstanding questions (for which we are seeking comment) 
regarding relative risks and benefits of that option in the timeframe 
envisioned. Commenters are encouraged to address how technologies could 
develop if a shorter lead time is selected. In particular, we request 
comment on the likelihood that WHR systems would be available for 
tractor engines in this time frame, and that WHR systems would achieve 
the projected level of reduction and the necessary reliability. We also 
request comment on whether it would be possible to apply the model 
based controls described in Section II.D.(2) (a)(i) to this many 
vocational engines in this time frame.

          Table II-14--Projected Tractor Engine Technologies and Reduction for Alternative 4 Standards
----------------------------------------------------------------------------------------------------------------
                                                                                      Market          Market
     %-Improvements beyond Phase 1, 2018 engine as baseline        SET reduction  penetration MY  penetration MY
                                                                        (%)          2021 (%)        2024 (%)
----------------------------------------------------------------------------------------------------------------
Turbo compound..................................................            1.82               5              10
WHR (Rankine cycle).............................................            3.58               4              15
Parasitics/Friction (Cyl Kits, pumps, FIE), lubrication.........            1.41              60             100
Aftertreatment..................................................            0.61              60             100
Exhaust Manifold Turbo Efficiency EGR Cooler VVT................            1.14              60             100
Combustion/FI/Control...........................................            1.11              60             100
Downsizing......................................................            0.29              20              30
                                                                                 -------------------------------
Market Penetration Weighted Package.............................................             2.1             4.2
----------------------------------------------------------------------------------------------------------------


[[Page 40203]]


  Table II-15--Projected Vocational Engine Technologies and Reduction for More Stringent Alternative Standards
----------------------------------------------------------------------------------------------------------------
                                                                                      Market          Market
     %-Improvements beyond Phase 1, 2018 engine as baseline        FTP reduction  penetration MY  penetration MY
                                                                        (%)          2021 (%)        2024 (%)
----------------------------------------------------------------------------------------------------------------
Model based control.............................................               2              30              40
Parasitics/Friction.............................................             1.5              70             100
EGR/Air/VVT/Turbo...............................................               1              70             100
Improved AT.....................................................             0.5              70             100
Combustion Optimization.........................................               1              70             100
Weighted reduction (%)-L/MHD/HHD................................  ..............             2.5             4.0
----------------------------------------------------------------------------------------------------------------

    The projected HDD engine package costs for both tractors and 
vocational engines in MYs 2021 and 2024 under Alternative 4 are shown 
in Table II-16. Note that, while the technology application rates in 
MY2024 under Alternative 4 are essentially identical to those for 
MY2027 under the proposal, the costs are about 5 to 11 percent higher 
under Alternative 4 due to learning effects and markup changes that are 
estimated to have occurred by MY2027 under Alternative 3. Note also 
that the agencies did not include any additional costs for accelerating 
technology development or to address potential in-use durability 
issues. We request comment on whether such costs would occur if we 
finalized this alternative. We also request comment on what steps could 
be taken to mitigate such costs.

            Table II-16--Expected Package Costs for HD Diesel Engines under Alternative 4 (2012$) \a\
----------------------------------------------------------------------------------------------------------------
                                                                       LHDD            MHDD            HHDD
           Model year              MHDD tractor    HHDD tractor     vocational      vocational      vocational
----------------------------------------------------------------------------------------------------------------
2021............................            $656            $656            $372            $345            $345
2024............................           1,885           1,885             493             457             457
----------------------------------------------------------------------------------------------------------------
Note:
\a\ Costs presented here include application rates.

    The agencies' analysis shows that, in the absence of additional 
costs for accelerating technology development or to address potential 
in-use durability issues, the costs associated with Alternative 4 would 
be very similar to those we project for the proposed standards. 
Alternative 4 would also have similar payback times and cost-
effectiveness. In other words, Alternative 4 would achieve some 
additional reductions for model years 2021 through 2026, with roughly 
proportional additional costs unless there were additional costs for 
accelerating development or for in-use durability issues. (Note that 
reductions and costs for MY 2027 and later would be equivalent for 
Alternative 4 and the proposed standards). In order to help make this 
assessment, we request comment on the following issues: whether 
manufacturers could meet these standards with three years less lead 
time, what additional expenses would be incurred to meet these 
standards with less lead time, and how reliable would the engines be if 
the manufacturers had to bring them to market three years earlier.
(3) Proposed EPA Engine Standards for N2O
    EPA is proposing to adopt the MY 2021 N2O engine 
standards that were originally proposed for Phase 1. The proposed level 
for Phase 2 would be 0.05 g/hp-hr with a default deterioration factor 
of 0.01 g/hp-hr, which we believe is technologically feasible because a 
number of engines meet this level today. This level of stringency is 
consistent with the agency's Phase 1 approach to set ``cap'' standards 
for N2O. EPA finalized Phase 1 standards for N2O 
as engine-based standards at 0.10 g/hp-hr and a 0.02 g/hp-hr default 
deterioration factor because the agency believes that emissions of this 
GHG are technologically related solely to the engine, fuel, and 
emissions aftertreatment systems, and the agency is not aware of any 
influence of vehicle-based technologies on these emissions. We continue 
to believe this approach is appropriate, but we believe that more 
stringent standards are appropriate to ensure that N2O 
emissions do not increase in the future. Note that NHTSA did not adopt 
standards for N2O because these emissions do not impact fuel 
consumption in a significant way, and is not proposing such standards 
for Phase 2 for the same reason.
    We are proposing this change at no additional cost and no 
additional benefit because manufacturers are generally meeting the 
proposed standard today. The purpose of this standard is to prevent 
increases in N2O emissions absent this proposed increase in 
stringency. We request comment on whether or not we should be 
considering additional costs for compliance. Similarly, we request 
comment on whether or not we should assume N2O increases in 
our ``No Action'' regulatory Alternatives 1a and 1b described in 
Section X.
    Although N2O is emitted in very small amounts, it can 
have a very significant impact on the climate. The global warming 
potential (GWP) of one molecule of N2O is 298 times that of 
one molecule CO2. Because N2O and CO2 
coincidentally have the same molar mass, this means that one gram of 
N2O would have the same impact on the climate as 298 grams 
of CO2. To further put this into perspective, the difference 
between the proposed N2O standard (and deterioration factor) 
and the current Phase 1 standard is 0.40 g/hp-hr of N2O 
emissions. This is equivalent to 11.92 g/hp-hr CO2. Over the 
same certification test cycle (i.e. EPA's HD FTP) the Phase 1 engine 
CO2 emissions standard ranges from 460 to 576 g/hp-hr, 
depending on the service class of the engine. Therefore, absent today's 
proposed action, engine N2O increases equivalent to 2.1 to 
2.6 percent of the Phase 1 CO2 standard could occur.
    We are proposing this lower cap because we have determined that

[[Page 40204]]

manufacturers generally are meeting this level today but in the future 
could increase N2O emissions up to the current Phase 1 cap 
standard. Because we do not believe any manufacturer would need to do 
anything more than recalibrate their SCR systems to comply, the lead 
time being provided would be sufficient. This section later describes 
why manufacturers may increase N2O emissions from SCR-
equipped compression-ignition engines in the absence of a lower 
N2O cap standard. We request comment on this. We also note 
that, as described in Section XI, EPA does not believe there is a 
similar opportunity to lower the pickup and van N2O standard 
because it was set at a more stringent level in Phase 1.
(a) N2O Formation
    N2O formation in modern diesel engines is a by-product 
of the SCR process. It is dependent on the SCR catalyst type, the 
NO2 to NOX ratio, the level of NOX 
reduction required, and the concentration of the reactants in the 
system (NH3 to NOX ratio).
    Two current engine/aftertreatment designs are driving 
N2O emission higher. The first is an increase in engine out 
NOX, which puts a higher NOX reduction burden on 
the SCR NOX emission control system. The second is an 
increase in NO2 formation from the diesel oxidation catalyst 
(DOC) located upstream of the passive catalyzed diesel particulate 
filter (CDPF). This increase in NO2 serves two functions: 
Improving passive CDPF regeneration and optimization of faster SCR 
reaction.\107\
---------------------------------------------------------------------------

    \107\ Hallstrom, K., Voss, K., and Shah, S., ``The Formation of 
N2O on the SCR Catalyst in a Heavy Duty US 2010 Emission 
Control System'', SAE Technical Paper 2013-01-2463.
---------------------------------------------------------------------------

    There are multiple mechanisms through which N2O can form 
in an SCR system:
    1. Low temperature formation of N2O over the DOC prior 
to the SCR catalyst.
    2. Low temperature formation of NH4NO3 with 
subsequent decomposition as exhaust temperatures increase, leading to 
conversion to N2O over the SCR catalyst.
    3. Formation of N2O from NO2 over the SCR 
catalyst at NO2 to NO ratios greater than 1:1. 
N2O formation increases significantly at 300 to 350 [deg]C.
    4. Formation of N2O from NH3 via partial 
oxidation over the ammonia slip catalyst.
    5. High-temperature N2O formation over the SCR catalyst 
due to NH3 oxidation facilitated by high SCR catalyst 
surface coverage of NH3.
    Thus, as discussed below, control of N2O formation 
requires precise optimization of SCR controls including thermal 
management and dosing rates, as well as catalyst composition.
(b) N2O Emission Reduction
    Through on-engine and reactor bench experiments, this same work 
showed that the key to reducing N2O emissions lies in 
intelligent emission control system design and operation, namely:
    1. Selecting the appropriate DOC and/or CDPF catalyst loadings to 
maintain NO2 to NO ratios at or below 1:1.
    2. Avoiding high catalyst surface coverage of NH3 though 
urea dosing management when the system is in the ideal N2O 
formation window.
    3. Utilizing thermal management to push the SCR inlet temperature 
outside of the N2O low-temperature formation window.
    EPA believes that reducing the standard from 0.1 g/hp-hr to 0.05 g/
hp-hr is feasible because most engines have emission rates that would 
meet this standard today and the others could meet it with minor 
calibration changes at no additional cost. Numerous studies have shown 
that diesel engine technologies can be fine-tuned to meet the current 
NOX and proposed N2O standards while still 
providing passive CDPF regeneration even with earlier generations of 
SCR systems. Currently model year 2014 systems have already moved on to 
newer generation systems in which the combined CDPF and SCR functions 
have been further optimized. The result of this is 18 of 24 engines in 
the EPA 2014 certification database emitting N2O at less 
than half of the 2014 standard, and thus below the proposed 
standard.\108\ Given the discussions in the literature, there are still 
additional calibration steps that can be taken to further reduce 
N2O emissions for the higher emitters to afford an adequate 
compliance margin and room to account for deterioration, without having 
an adverse effect on criteria pollutant emissions.
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    \108\ http://www.epa.gov/otaq/crttst.htm.

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[[Page 40205]]

[GRAPHIC] [TIFF OMITTED] TP13JY15.001

    It is important to note, however, that there is a trade off when 
trying to optimize SCR systems to achieve peak NOX reduction 
efficiencies. When transitioning from a <93 percent efficient MY 2011 
system to a 98 percent efficient system of the future, lowering the 
N2O cap to 0.05 g/hp-hr would put constraints on the 
techniques that can be applied to improve efficiency. If system 
designers push the NH3 to NOX ratio higher to try 
and achieve the maximum possible NOX reduction, it could 
increase N2O emissions. If EPA were to adopt a very low 
NOX standard (e.g., 0.02 g/hp-hr) over existing test cycles, 
some reductions would be needed throughout the hot portion of the cycle 
(although most of the reductions would have to come from the cold start 
portion of the test cycle). Thermal management would need to play a key 
role, and reducing catalyst light-off time would move the SCR catalyst 
through the ammonium nitrate formation and decomposition thermal range 
quicker, thus lowering N2O emissions. An increase in the 
NH3 to NOX ratio could also further reduce 
NOX emissions; however this would also adversely affect 
NH3 slip and N2O formation. The inability of 
NH3 slip catalysts to handle the increased NH3 
load and the EPA NH3 slip limit of 10 ppm would guard 
against this NH3 to NOX ratio increase, and thus 
subsequent N2O increase.
    In summary, EPA believes that engine manufacturers would be able to 
respond with highly efficient NOX reducing systems that can 
meet the proposed lower N2O cap of 0.05 g/hp-hr with no 
additional cost or lead time. When optimizing SCR systems for better 
NOX reduction efficiency, that optimization includes 
lowering the emissions of undesirable side reactions, including those 
that form N2O.
(4) EPA Engine Standards for Methane
    EPA is proposing to apply the Phase 1 methane engine standards to 
the Phase 2 program. EPA adopted the cap standards for CH4 
(along with N2O standards) as engine-based standards because 
the agency believes that emissions of this GHG are technologically 
related solely to the engine, fuel, and emissions aftertreatment 
systems, and the agency is not aware of any influence of vehicle-based 
technologies on these emissions. Note that NHTSA did not adopt 
standards for CH4 (or N2O) because these 
emissions do not impact fuel consumption in a significant way, and is 
not proposing CH4 standards for Phase 2 either.
    EPA continues to believe that manufacturers of most engine 
technologies will be able to comply with the Phase 1 CH4 
standard with no technological improvements. We note that we are not 
aware of any new technologies that would allow us to adopt more 
stringent standards at this time. We request comment on this.
(5) Compliance Provisions and Flexibilities for Engine Standards
    The agencies are proposing to continue most of the Phase 1 
compliance provisions and flexibilities for the Phase 2 engine 
standards.
(a) Averaging, Banking, and Trading
    The agencies' general approach to averaging is discussed in Section 
I. We are not proposing to offer any special credits to engine 
manufacturers. Except for early credits and advanced technology 
credits, the agencies propose to retain all Phase 1 credit 
flexibilities and limitations to continue for use in the Phase 2 
program.
    As discussed below, EPA is proposing to change the useful life for 
LHD

[[Page 40206]]

engines for GHG emissions from the current 10 years/110,000 miles to 15 
years/150,000 miles to be consistent with the useful life of criteria 
pollutants recently updated in EPA's Tier 3 rule. In order to ensure 
that banked credits would maintain their value in the transition from 
Phase 1 to Phase 2, NHTSA and EPA propose an adjustment factor of 1.36 
(i.e., 150,000 mile / 110,000 miles) for credits that are carried 
forward from Phase 1 to the MY 2021 and later Phase 2 standards. 
Without this adjustment factor the proposed change in useful life would 
effectively result in a discount of banked credits that are carried 
forward from Phase 1 to Phase 2, which is not the intent of the change 
in the useful life. See Sections V and VI for additional discussion of 
similar adjustments of vehicle-based credits.
(b) Request for Comment on Changing Global Warming Potential Values in 
the Credit Program for CH4 and N2O
    The Phase 1 rule included a compliance alternative allowing heavy-
duty manufacturers and conversion companies to comply with the 
respective methane or nitrous oxide standards by means of over-
complying with CO2 standards (40 CFR 1036.705(d)). The 
heavy-duty rules allow averaging only between vehicles or engines of 
the same designated type (referred to as an ``averaging set'' in the 
rules). Specifically, the phase 1 heavy-duty rulemaking added a 
CO2 credits program which allowed heavy-duty manufacturers 
to average and bank pollutant emissions to comply with the methane and 
nitrous oxide requirements after adjusting the CO2 emission 
credits based on the relative GHG equivalents. To establish the GHG 
equivalents used by the CO2 credits program, the Phase 1 
rule incorporated the IPCC Fourth Assessment Report global warming 
potential (GWP) values of 25 for CH4 and 298 for 
N2O, which are assessed over a 100 year lifetime.
    Since the Phase 1 rule was finalized, a new IPCC report has been 
released (the Fifth Assessment Report), with new GWP estimates. This is 
prompting us to look again at the relative CO2 equivalency 
of methane and nitrous oxide and to seek comment on whether the methane 
and nitrous oxide GWPs used to establish the GHG equivalency value for 
the CO2 Credit program should be updated to those 
established by IPCC in its Fifth Assessment Report. The Fifth 
Assessment Report provides four 100 year GWPs for methane ranging from 
28 to 36 and two 100 year GWPs for nitrous oxide, either 265 or 298. 
Therefore, we not only request comment on whether to update the GWP for 
methane and nitrous oxide to that of the Fifth Assessment Report, but 
also on which value to use from this report.
(c) In-Use Compliance and Useful Life
    Consistent with Section 202(a)(1) and 202 (d) of the CAA, for Phase 
1, EPA established in-use standards for heavy-duty engines. Based on 
our assessment of testing variability and other relevant factors, we 
established in-use standards by adding a 3 percent adjustment factor to 
the full useful life emissions and fuel consumption results measured in 
the EPA certification process to address measurement variability 
inherent in comparing results among different laboratories and 
different engines. See 40 CFR part 1036. The agencies are not proposing 
to change this for Phase 2, but request comment on whether this 
allowance is still necessary.
    We note that in Phase 1, we applied these standards to only certain 
engine configurations in each engine family (often called the parent 
rating). We welcome comment on whether the agencies should set Phase 2 
CO2 and fuel consumption standards for the other ratings 
(often called the child ratings) within an engine family. We are not 
proposing specific engine standards for child ratings in Phase 2 
because we are proposing to include the actual engine's fuel map in the 
vehicle certification. We believe this approach appropriately addresses 
our concern that manufacturers control CO2 emissions and 
fuel consumption from all in-use engine configurations within an engine 
family.
    In Phase 1, EPA set the useful life for engines and vehicles with 
respect to GHG emissions equal to the respective useful life periods 
for criteria pollutants. In April 2014, as part of the Tier 3 light-
duty vehicle final rule, EPA extended the regulatory useful life period 
for criteria pollutants to 150,000 miles or 15 years, whichever comes 
first, for Class 2b and 3 pickup trucks and vans and some light-duty 
trucks (79 FR 23414, April 28, 2014). As described in Section V, EPA is 
proposing that the Phase 2 GHG standards for vocational vehicles at or 
below 19,500 lbs GVWR apply over the same useful life of 150,000 miles 
or 15 years. To be consistent with that proposed change, we are also 
proposing that the Phase 2 GHG standards for engines used in vocational 
vehicles at or below 19,500 lbs GVWR apply over the same useful life of 
150,000 miles or 15 years. NHTSA proposes to use the same useful life 
values as EPA for all vocational vehicles.
    We are proposing to continue regulatory allowance in 40 CFR 
1036.150(g) that allows engine manufacturers to use assigned 
deterioration factors (DFs) for most engines without performing their 
own durability emission tests or engineering analysis. However, the 
engines would still be required to meet the standards in actual use 
without regard to whether the manufacturer used the assigned DFs. This 
allowance is being continued as an interim provision and may be 
discontinued for later phases of standards as more information becomes 
known. Manufacturers are allowed to use an assigned additive DF of 0.0 
g/bhp-hr for CO2 emissions from any conventional engine 
(i.e., an engine not including advance or off-cycle technologies). Upon 
request, we could allow the assigned DF for CO2 emissions 
from engines including advance or off-cycle technologies, but only if 
we determine that it would be consistent with good engineering 
judgment. We believe that we have enough information about in-use 
CO2 emissions from conventional engines to conclude that 
they will not increase as the engines age. However, we lack such 
information about the more advanced technologies.
    We are also requesting comment on how to apply DFs to low level 
measurements where test-to-test variability may be larger than the 
actual deterioration rates being measured, such as might occur with 
N2O. Should we allow statistical analysis to be used to 
identifying trends rather than basing the DF on the highest measured 
value? How would we allow this where emission deterioration is not 
linear, such as saw-tooth deterioration related to maintenance or other 
offsetting emission effects causing emissions to peak before the end of 
the useful life? Finally, EPA requests comment on whether a similar 
allowance would be appropriate for criteria pollutants as well.
(d) Alternate CO2 Standards
    In the Phase 1 rulemaking, the agencies proposed provisions to 
allow certification to alternate CO2 engine standards in 
model years 2014 through 2016. This flexibility was intended to address 
the special case of needed lead time to implement new standards for a 
previously unregulated pollutant. Since that special case does not 
apply for Phase 2, we are not proposing a similar flexibility in this 
rulemaking. We also request comment on whether this allowance should be 
eliminated for Phase 1 engines.

[[Page 40207]]

(e) Proposed Approach to Standards and Compliance Provisions for 
Natural Gas Engines
    EPA is also proposing certain clarifying changes to its rules 
regarding classification of natural gas engines. This proposal relates 
to standards for all emissions, both greenhouse gases and criteria 
pollutants. These clarifying changes are intended to reflect the status 
quo, and therefore should not have any associated costs.
    EPA emission standards have always applied differently for 
gasoline-fueled and diesel-fueled engines. The regulations in 40 CFR 
part 86 implement these distinctions by dividing engines into Otto-
cycle and Diesel-cycle technologies. This approach led EPA to 
categorize natural gas engines according to their design history. A 
diesel engine converted to run on natural gas was classified as a 
diesel-cycle engine; a gasoline engine converted to run on natural gas 
was classified as an Otto-cycle engine.
    The Phase 1 rule described our plan to transition to a different 
approach, consistent with our nonroad programs, in which we divide 
engines into compression-ignition and spark-ignition technologies based 
only on the operating characteristics of the engines.\109\ However, the 
Phase 1 rule included a provision allowing us to continue with the 
historic approach on an interim basis.
---------------------------------------------------------------------------

    \109\ See 40 CFR 1036.108.
---------------------------------------------------------------------------

    Under the existing EPA regulatory definitions of ``compression-
ignition'' and ``spark-ignition'', a natural gas engine would generally 
be considered compression-ignition if it operates with lean air-fuel 
mixtures and uses a pilot injection of diesel fuel to initiate 
combustion, and would generally be considered spark-ignition if it 
operates with stoichiometric air-fuel mixtures and uses a spark plug to 
initiate combustion.
    EPA's basic premise here is that natural gas engines performing 
similar in-use functions should be subject to similar regulatory 
requirements. The compression-ignition emission standards and testing 
requirements reflect the operating characteristics for the full range 
of heavy-duty vehicles, including substantial operation in long-haul 
service characteristic of tractors. The spark-ignition emission 
standards and testing requirements do not include some of those 
provisions related to use in long-haul service or other applications 
where diesel engines predominate, such as steady-state testing, Not-to-
Exceed standards, and extended useful life. We believe it would be 
inappropriate to apply the spark-ignition standards and requirements to 
natural gas engines that would be used in applications mostly served by 
diesel engines today. We are therefore proposing to replace the interim 
provision described above with a differentiated approach to 
certification of natural gas engines across all of the EPA standards--
for both GHGs and criteria pollutants. Under the proposed clarifying 
amendment, we would require manufacturers to divide all their natural 
gas engines into primary intended service classes, as we already 
require for compression-ignition engines, whether or not the engine has 
features that otherwise could (in theory) result in classification as 
SI under the current rules. Any natural gas engine qualifying as a 
medium heavy-duty engine (19,500 to 33,000 lbs GVWR) or a heavy heavy-
duty engine (over 33,000 lbs GVWR) would be subject to all the emission 
standards and other requirements that apply to compression-ignition 
engines.
    Table II-17 describes the provisions that would apply differently 
for compression-ignition and spark-ignition engines:

 Table II-17--Regulatory Provisions That Are Different for Compression-
                   Ignition and Spark-Ignition Engines
------------------------------------------------------------------------
           Provision             Compression-ignition    Spark-ignition
------------------------------------------------------------------------
Transient duty cycle..........  40 CFR part 86,         40 CFR part 86,
                                 Appendix I, paragraph   Appendix I,
                                 (f)(2) cycle; divide    paragraph
                                 by 1.12 to de-          (f)(1) cycle.
                                 normalize.
Ramped-modal test (SET).......  yes...................  no.
NTE standards.................  yes...................  no.
Smoke standard................  yes...................  no.
Manufacturer-run in-use         yes...................  no.
 testing.
ABT--pollutants...............  NOX, PM...............  NOX, NMHC.
ABT-- transient conversion      6.5...................  6.3.
 factor.
ABT--averaging set............  Separate averaging      One averaging
                                 sets for light,         set for all SI
                                 medium, and heavy       engines.
                                 HDDE.
Useful life...................  110,000 miles for       110,000 miles
                                 light HDDE.
                                185,000 miles for
                                 medium HDDE..
                                435,000 miles for
                                 heavy HDDE..
Warranty......................  50,000 miles for light  50,000 miles.
                                 HDDE.
                                100,000 miles for
                                 medium HDDE..
                                100,000 miles for
                                 heavy HDDE..
Detailed AECD description.....  yes...................  no.
Test engine selection.........  highest injected fuel   most likely to
                                 volume.                 exceed emission
                                                         standards.
------------------------------------------------------------------------

    The onboard diagnostic requirements already differentiate 
requirements by fuel type, so there is no need for those provisions to 
change based on the considerations of this section.
    We are not aware of any currently certified engines that would 
change from compression-ignition to spark-ignition under the proposed 
clarified approach. Nonetheless, because these proposed standards 
implicate rules for criteria pollutants (as well as GHGs), the 
provisions of CAA section 202(a)(3)(C) apply (for the criteria 
pollutants), notably the requirement of four years lead time. We are 
therefore proposing to continue to apply the existing interim provision 
through model year 2020.\110\

[[Page 40208]]

Starting in model year 2021, all the provisions would apply as 
described above. Manufacturers would not be permitted to certify any 
engine families using carryover emission data if a particular engine 
model switched from compression-ignition to spark-ignition, or vice 
versa. However, as noted above, in practice these vehicles are already 
being certified as CI engines, so we view these changes as 
clarifications ratifying the current status quo.
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    \110\ Section 202(a)(2), applicable to emissions of greenhouse 
gases, does not mandate a specific period of lead time, but EPA sees 
no reason for a different compliance date here for GHGs and criteria 
pollutants. This is also true with respect to the closed crankcase 
emission discussed in the following subsection.
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    We are also proposing that these provisions would apply equally to 
engines fueled by any fuel other than gasoline or ethanol, should such 
engines be produced in the future. Given the current and historic 
market for vehicles above 19,500 lbs GVWR, EPA believes any 
alternative-fueled vehicles in this weight range would be competing 
primarily with diesel vehicles and should be subject to the same 
requirements as them. We request comment on all aspects of classifying 
natural-gas and other engines for purposes of applying emission 
standards. See Sections XI and XII for additional discussion of natural 
gas fueled engines.
(f) Crankcase Emissions From Natural Gas Engines
    EPA is proposing one fuel-specific provision for natural gas 
engines, likewise applicable to all pollutant emissions, both GHGs and 
criteria pollutant emissions. Note that we are also proposing other 
vehicle-level emissions controls for the natural gas storage tanks and 
refueling connections. These are presented in Section XIII.
    EPA is proposing to require that all natural gas-fueled engines 
have closed crankcases, rather than continuing the provision that 
allows venting to the atmosphere all crankcase emissions from all 
compression-ignition engines. This has been allowed as long as these 
vented crankcase emissions are measured and accounted for as part of an 
engine's tailpipe emissions. This allowance has historically been in 
place to address the technical limitations related to recirculating 
diesel-fueled engines' crankcase emissions, which have high PM 
emissions, back into the engine's air intake. High PM emissions vented 
into the intake of an engine can foul turbocharger compressors and 
aftercooler heat exchangers. In contrast, historically EPA has mandated 
closed crankcase technology on all gasoline fueled engines and all 
natural gas spark-ignition engines.\111\ The inherently low PM 
emissions from these engines posed no technical barrier to a closed 
crankcase mandate. Because natural gas-fueled compression ignition 
engines also have inherently low PM emissions, there is no 
technological limitation that would prevent manufacturers from closing 
the crankcase and recirculating all crankcase gases into a natural gas-
fueled compression ignition engine's air intake. We are requesting 
comment on the costs and effectiveness of technologies that we have 
identified to comply with these provisions. In addition, EPA is 
proposing that this revised standard not take effect until the 2021 
model year, consistent with the requirement of section 202(a)(3)(C) to 
provide four years lead time.


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    \111\ See 40 CFR 86.008-10(c).
---------------------------------------------------------------------------

III. Class 7 and 8 Combination Tractors

    Class 7 and 8 combination tractors-trailers contribute the largest 
portion of the total GHG emissions and fuel consumption of the heavy-
duty sector, approximately two-thirds, due to their large payloads, 
their high annual miles traveled, and their major role in national 
freight transport.\112\ These vehicles consist of a cab and engine 
(tractor or combination tractor) and a trailer.\113\ In general, 
reducing GHG emissions and fuel consumption for these vehicles would 
involve improvements to all aspects of the vehicle.
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    \112\ The on-highway Class 7 and 8 combination tractor-trailers 
constitute the vast majority of this regulatory category. A small 
fraction of combination tractors are used in off-road applications 
and are regulated differently, as described in Section III.C.
    \113\ ``Tractor'' is defined in 49 CFR 571.3 to mean ``a truck 
designed primarily for drawing other motor vehicles and not so 
constructed as to carry a load other than a part of the weight of 
the vehicle and the load so drawn.''
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    As we found during the development in Phase 1 and as continues to 
be true in the industry today, the heavy-duty combination tractor-
trailer industry consists of separate tractor manufacturers and trailer 
manufacturers. We are not aware of any manufacturer that typically 
assembles both the finished truck and the trailer and introduces the 
combination into commerce for sale to a buyer. There are also large 
differences in the kinds of manufacturers involved with producing 
tractors and trailers. For HD highway tractors and their engines, a 
relatively limited number of manufacturers produce the vast majority of 
these products. The trailer manufacturing industry is quite different, 
and includes a large number of companies, many of which are relatively 
small in size and production volume. Setting standards for the products 
involved--tractors and trailers--requires recognition of the large 
differences between these manufacturing industries, which can then 
warrant consideration of different regulatory approaches. Thus, 
although tractor-trailers operate essentially as a unit from both a 
commercial standpoint and for purposes of fuel efficiency and 
CO2 emissions, the agencies have developed separate proposed 
standards for each.
    Based on these industry characteristics, EPA and NHTSA believe that 
the most appropriate regulatory approach for combination tractors and 
trailers is to establish standards for tractors separately from 
trailers. As discussed below in Section IV, the agencies are also 
proposing standards for certain types of trailers.

A. Summary of the Phase 1 Tractor Program

    The design of each tractor's cab and drivetrain determines the 
amount of power that the engine must produce in moving the truck and 
its payload down the road. As illustrated in Figure III-1, the loads 
that require additional power from the engine include air resistance 
(aerodynamics), tire rolling resistance, and parasitic losses 
(including accessory loads and friction in the drivetrain). The 
importance of the engine design is that it determines the basic GHG 
emissions and fuel consumption performance for the variety of demands 
placed on the vehicle, regardless of the characteristics of the cab in 
which it is installed.

[[Page 40209]]

[GRAPHIC] [TIFF OMITTED] TP13JY15.002

    Accordingly, for Class 7 and 8 combination tractors, the agencies 
adopted two sets of Phase 1 tractor standards for fuel consumption and 
CO2 emissions. The CO2 emission and fuel 
consumption reductions related to engine technologies are recognized in 
the engine standards. For vehicle-related emissions and fuel 
consumption, tractor manufacturers are required to meet vehicle-based 
standards. Compliance with the vehicle standard must be determined 
using the GEM vehicle simulation tool.
---------------------------------------------------------------------------

    \114\ Adapted from Figure 4.1. Class 8 Truck Energy Audit, 
Technology Roadmap for the 21st Century Truck Program: A Government-
Industry Research Partnership, 21CT-001, December 2000.
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    The Phase 1 tractor standards were based on several key attributes 
related to GHG emissions and fuel consumption that reasonably represent 
the many differences in utility and performance among these vehicles. 
Attribute-based standards in general recognize the variety of functions 
performed by vehicles and engines, which in turn can affect the kind of 
technology that is available to control emissions and reduce fuel 
consumption, or its effectiveness. Attributes that characterize 
differences in the design of vehicles, as well as differences in how 
the vehicles will be employed in-use, can be key factors in evaluating 
technological improvements for reducing CO2 emissions and 
fuel consumption. Developing an appropriate attribute-based standard 
can also avoid interfering with the ability of the market to offer a 
variety of products to meet the customer's demand. The Phase 1 tractor 
standards differ depending on GVWR (i.e., whether the truck is Class 7 
or Class 8), the height of the roof of the cab, and whether it is a 
``day cab'' or a ``sleeper cab.'' These later two attributes are 
important because the height of the roof, designed to correspond to the 
height of the trailer, significantly affects air resistance, and a 
sleeper cab generally corresponds to the opportunity for extended 
duration idle emission and fuel consumption improvements. Based on 
these attributes, the agencies created nine subcategories within the 
Class 7 and 8 combination tractor category. The Phase 1 rules set 
standards for each of them. Phase 1 standards began with the 2014 model 
year and were followed with more stringent standards following in model 
year 2017.\115\ The standards represent an overall fuel consumption and 
CO2 emissions reduction up to 23 percent from the tractors 
and the engines installed in them when compared to a baseline 2010 
model year tractor and engine without idle shutdown technology. 
Although the EPA and NHTSA standards are expressed differently (grams 
of CO2 per ton-mile and gallons per 1,000 ton-mile 
respectively), the standards are equivalent.
---------------------------------------------------------------------------

    \115\ Manufacturers may voluntarily opt-in to the NHTSA fuel 
consumption standards in model years 2014 or 2015. Once a 
manufacturer opts into the NHTSA program it must stay in the program 
for all optional MYs.
---------------------------------------------------------------------------

    In Phase 1, the agencies allowed manufacturers to certify certain 
types of combination tractors as vocational vehicles. These are 
tractors that do not typically operate at highway speeds, or would 
otherwise not benefit from efficiency improvements designed for line-
haul tractors (although standards would still apply to the engines 
installed in these vehicles). The agencies created a subcategory of 
``vocational tractors,'' or referred to as ``special purpose tractors'' 
in 40 CFR part 1037, because real world operation of these tractors is 
better represented by our Phase 1 vocational vehicle duty cycle than 
the tractor duty cycles. Vocational tractors are subject to the 
standards for vocational vehicles rather than the combination tractor 
standards. In addition, specific vocational tractors and heavy-duty 
vocational vehicles primarily designed to perform work off-road or 
having tires installed with a maximum speed rating at or below 55 mph 
are exempted from the Phase 1 standards.
    In Phase 1, the agencies also established separate performance 
standards for the engines manufactured for use in these tractors. EPA's 
engine-based CO2 standards and NHTSA's engine-based fuel 
consumption standards are being implemented using EPA's existing test 
procedures and regulatory structure for criteria pollutant emissions 
from medium- and heavy-duty engines. These engine standards vary 
depending on engine size linked to intended vehicle service class 
(which are the same service classes used for many years for EPA's 
criteria pollutant standards).
    Manufacturers demonstrate compliance with the Phase 1 tractor 
standards using the GEM simulation tool. As explained in Section II 
above, GEM is a customized vehicle simulation model which is the 
preferred approach to demonstrating compliance testing for combination 
tractors rather than chassis dynamometer testing used in light-duty 
vehicle compliance. As discussed in the development of HD Phase 1 and 
recommended by the NAS 2010 study,

[[Page 40210]]

a simulation tool is the preferred approach for HD tractor compliance 
because of the extremely large number of vehicle configurations.\116\ 
The GEM compliance tool was developed by EPA and is an accurate and 
cost-effective alternative to measuring emissions and fuel consumption 
while operating the vehicle on a chassis dynamometer. Instead of using 
a chassis dynamometer as an indirect way to evaluate real world 
operation and performance, various characteristics of the vehicle are 
measured and these measurements are used as inputs to the model. For HD 
Phase 1, these characteristics relate to key technologies appropriate 
for this category of truck including aerodynamic features, weight 
reductions, tire rolling resistance, the presence of idle-reducing 
technology, and vehicle speed limiters. The model also assumes the use 
of a representative typical engine in compliance with the separate, 
applicable Phase 1 engine standard. Using these inputs, the model is 
used to quantify the overall performance of the vehicle in terms of 
CO2 emissions and fuel consumption. CO2 emission 
reduction and fuel consumption technologies not measured by the model 
must be evaluated separately, and the HD Phase 1 rules establish 
mechanisms allowing credit for such ``off-cycle'' technologies.
---------------------------------------------------------------------------

    \116\ National Academy of Science. ``Technologies and Approaches 
to Reducing the Fuel Consumption of Medium- and Heavy-Duty 
Vehicles.'' 2010. Recommendation 8-4 stated ``Simulation modeling 
should be used with component test data and additional tested inputs 
from powertrain tests, which could lower the cost and administrative 
burden yet achieve the needed accuracy of results.''
---------------------------------------------------------------------------

    In addition to the final Phase 1 tractor-based standards for 
CO2, EPA adopted a separate standard to reduce leakage of 
HFC refrigerant from cabin air conditioning (A/C) systems from 
combination tractors, to apply to the tractor manufacturer. This HFC 
leakage standard is independent of the CO2 tractor standard. 
Manufacturers can choose technologies from a menu of leak-reducing 
technologies sufficient to comply with the standard, as opposed to 
using a test to measure performance.
    The Phase 1 program also provided several flexibilities to advance 
the goals of the overall program while providing alternative pathways 
to achieve compliance. The primary flexibility is the averaging, 
banking, and trading program which allows emissions and fuel 
consumption credits to be averaged within an averaging set, banked for 
up to five years, or traded among manufacturers. Manufacturers with 
credit deficits were allowed to carry-forward credit deficits for up to 
three model years, similar to the LD GHG and CAFE carry-back credits. 
Phase 1 also included several interim provisions, such as incentives 
for advanced technologies and provisions to obtain credits for 
innovative technologies (called off-cycle in the Phase 2 program) not 
accounted for by the HD Phase 1 version of GEM or for certifying early.

B. Overview of the Proposed Phase 2 Tractor Program

    The proposed HD Phase 2 program is similar in many respects to the 
Phase 1 approach. The agencies are proposing to maintain the Phase 1 
attribute-based regulatory structure in terms of dividing the tractor 
category into the same nine subcategories based on the tractor's GVWR, 
cab configuration, and roof height. This structure is working well in 
the implementation of Phase 1. The one area where the agencies are 
proposing to change the regulatory structure is related to heavy-haul 
tractors. As noted above, the Phase 1 regulations include a set of 
provisions that allow vocational tractors to be treated as vocational 
vehicles. However, because the agencies propose to include the 
powertrain as part of the technology basis for the tractor and 
vocational vehicle standards in Phase 2, we are proposing to classify a 
certain set of these vocational tractors as heavy-haul tractors and 
subject them to a separate tractor standard that reflects their unique 
powertrain requirements and limitations in application of technologies 
to reduce fuel consumption and CO2 emissions.\117\
---------------------------------------------------------------------------

    \117\ See 76 FR 57138 for Phase 1 discussion. See 40 CFR 
1037.801 for proposed Phase 2 heavy-haul tractor regulatory 
definition.
---------------------------------------------------------------------------

    The agencies propose to also retain much of the certification and 
compliance structure developed in Phase 1 but to simplify end of the 
year reporting. The agencies propose that the Phase 2 tractor 
CO2 emissions and fuel consumption standards, as in Phase 1, 
be aligned.\118\ The agencies also propose to continue to have separate 
engine and vehicle standards to drive technology improvements in both 
areas. The reasoning behind the proposal to maintain separate standards 
is discussed above in Section II.B.2. As in Phase 1, the agencies 
propose to certify tractors using the GEM simulation tool and to 
require manufacturers to evaluate the performance of subsystems through 
testing (the results of this testing to be used as inputs to the GEM 
simulation tool). Other aspects of the proposed HD Phase 2 
certification and compliance program also mirror the Phase 1 program, 
such as maintaining a single reporting structure to satisfy both 
agencies, requiring limited data at the beginning of the model year for 
certification, and determining compliance based on end of year reports. 
In the Phase 1 program, manufacturers participating in the ABT program 
provided 90 day and 270 day reports after the end of the model year. 
The agencies required two reports for the initial program to help 
manufacturers become familiar with the reporting process. For the Phase 
2 program, the agencies propose that manufacturers would only be 
required to submit one end of the year report, which would simplify 
reporting.
---------------------------------------------------------------------------

    \118\ Fuel consumption is calculated from CO2 using 
the conversion factor of 10,180 grams of CO2 per gallon 
for diesel fuel.
---------------------------------------------------------------------------

    Even though many aspects of the proposed HD Phase 2 program are 
similar to Phase 1, there are some key differences. While Phase 1 
focused on reducing CO2 emissions and fuel consumption in 
tractors through the application of existing (``off-the-shelf'') 
technologies, the proposed HD Phase 2 standards seek additional 
reductions through increased use of existing technologies and the 
development and deployment of more advanced technologies. To evaluate 
the effectiveness of a more comprehensive set of technologies, the 
agencies propose several additional inputs to GEM. The proposed set of 
inputs includes the Phase 1 inputs plus parameters to assess the 
performance of the engine, transmission, and driveline. Specific inputs 
for, among others, predictive cruise control, automatic tire inflation 
systems, and 6x2 axles would now be required. Manufacturers would 
conduct component testing to obtain the values for these technologies 
(should they choose to use them), which testing values would then be 
input into the GEM simulation tool. See Section III.D.2 below. To 
effectively assess performance of the technologies, the agencies also 
propose to change some aspects of the drive cycle used in certification 
through the addition of road grade. To reflect the existing trailer 
market, the agencies are proposing to refine the aerodynamic test 
procedure for high roof cabs by adding some aerodynamic improving 
devices to the reference trailer (used for determining the relative 
aerodynamic performance of the tractor). The agencies also propose to 
change the aerodynamic certification test procedure to capture 
aerodynamic improvement of trailers and the impact of wind on tractor 
aerodynamic performance. The agencies are also proposing to change some 
of the interim provisions developed in Phase 1 to reflect the maturity 
of the program and

[[Page 40211]]

reduced need and justification for some of the Phase 1 flexibilities. 
Further discussions on all of these matters are covered in the 
following sections.

C. Proposed Phase 2 Tractor Standards

    EPA is proposing CO2 standards and NHTSA is proposing 
fuel consumption standards for new Class 7 and 8 combination tractors. 
In addition, EPA is proposing to maintain the HFC standards for the air 
conditioning systems that were adopted in Phase 1. EPA is also seeking 
comment on new standards to further control emissions of particulate 
matter (PM) from auxiliary power units (APU) installed in tractors that 
would prevent an unintended consequence of increasing PM emissions from 
tractors during long duration idling.
    This section describes in detail the proposed standards. In 
addition to describing the proposed alternative (``Alternative 3''), in 
Section III.D.2.f we also detail another alternative (``Alternative 
4''). Alternative 4 provides less lead time than the proposed set of 
standards but may provide more net benefits in the form of greater 
emission and fuel consumption reductions (with somewhat higher costs) 
in the early years of the program. The agencies believe Alternative 4 
has the potential to be maximum feasible and appropriate as discussed 
later in this section.
    The agencies welcome comment on all aspects of the proposed 
standards and the alternative standards described in Section III.D.2.f. 
Commenters are encouraged to address all aspects of feasibility 
analysis, including costs, the likelihood of developing the technology 
to achieve sufficient relaibility within the proposed and alternative 
lead-times, and the extent to which the market could utilize the 
technology. It would be helpful if comments addressed these issues 
separately for each type of technology.
(1) Proposed Fuel Consumption and CO2 Standards
    The proposed fuel consumption and CO2 standards for the 
tractor cab are shown below in Table III-1. These proposed standards 
would achieve reductions of up to 24 percent compared to the 2017 model 
year baseline level when fully phased in beginning in the 2027 MY.\119\ 
The proposed standards for Class 7 are described as ``Day Cabs'' 
because we are not aware of any Class 7 sleeper cabs in the market 
today; however, the agencies propose to require any Class 7 tractor, 
regardless of cab configuration, meet the standards described as 
``Class 7 Day Cab.'' We welcome comment on this proposed approach.
---------------------------------------------------------------------------

    \119\ Since the HD Phase 1 tractor standards fully phase-in by 
the MY 2017, this is the logical baseline year.
---------------------------------------------------------------------------

    The agencies' analyses, as discussed briefly below and in more 
detail later in this preamble and in the draft RIA Chapter 2, indicate 
that these proposed standards, if finalized, would be maximum feasible 
(within the meaning of 49 U.S.C. Section 32902 (k)) and would be 
appropriate under each agency's respective statutory authorities. The 
agencies solicit comment on all aspects of these analyses.

 Table III-1--Proposed Phase 2 Heavy-Duty Combination Tractor EPA Emissions Standards (g CO2/ton-mile) and NHTSA
                                 Fuel Consumption Standards (gal/1,000 ton-mile)
----------------------------------------------------------------------------------------------------------------
                                                                              Day cab               Sleeper cab
                                                                 -----------------------------------------------
                                                                      Class 7         Class 8         Class 8
----------------------------------------------------------------------------------------------------------------
2021 Model Year CO2 Grams per Ton-Mile..........................................................................
----------------------------------------------------------------------------------------------------------------
Low Roof........................................................              97              78              70
Mid Roof........................................................             107              84              78
High Roof.......................................................             109              86              77
----------------------------------------------------------------------------------------------------------------
2021 Model Year Gallons of Fuel per 1,000 Ton-Mile..............................................................
----------------------------------------------------------------------------------------------------------------
Low Roof........................................................          9.5285          7.6621          6.8762
Mid Roof........................................................         10.5108          8.2515          7.6621
High Roof.......................................................         10.7073          8.4479          7.5639
----------------------------------------------------------------------------------------------------------------
2024 Model Year CO2 Grams per Ton-Mile..........................................................................
----------------------------------------------------------------------------------------------------------------
Low Roof........................................................              90              72              64
Mid Roof........................................................             100              78              71
High Roof.......................................................             101              79              70
----------------------------------------------------------------------------------------------------------------
2024 Model Year and Later Gallons of Fuel per 1,000 Ton-Mile....................................................
----------------------------------------------------------------------------------------------------------------
Low Roof........................................................          8.8409          7.0727          6.2868
Mid Roof........................................................          9.8232          7.6621          6.9745
High Roof.......................................................          9.9214          7.7603          6.8762
----------------------------------------------------------------------------------------------------------------
2027 Model Year CO2 Grams per Ton-Mile..........................................................................
----------------------------------------------------------------------------------------------------------------
Low Roof........................................................              87              70              62
Mid Roof........................................................              96              76              69
High Roof.......................................................              96              76              67
----------------------------------------------------------------------------------------------------------------
2027 Model Year and Later Gallons of Fuel per 1,000 Ton-Mile....................................................
----------------------------------------------------------------------------------------------------------------
Low Roof........................................................          8.5462          6.8762          6.0904
Mid Roof........................................................          9.4303          7.4656          6.7780

[[Page 40212]]

 
High Roof.......................................................          9.4303          7.4656          6.5815
----------------------------------------------------------------------------------------------------------------

    It should be noted that the proposed HD Phase 2 CO2 and 
fuel consumptions standards are not directly comparable to the Phase 1 
standards. This is because the agencies are proposing several test 
procedure changes to more accurately reflect real world operation of 
tractors. These changes will result in the following differences. 
First, the same vehicle evaluated using the proposed HD Phase 2 version 
of GEM will obtain higher (i.e. less favorable) CO2 and fuel 
consumption values because the Phase 2 drive cycles include road grade. 
Road grade, which (of course) exists in the real-world, requires the 
engine to operate at higher horsepower levels to maintain speed while 
climbing a hill. Even though the engine saves fuel on a downhill 
section, the overall impact increases CO2 emissions and fuel 
consumption. The second of the key differences between the 
CO2 and fuel consumption values in Phase 1 and Phase 2 is 
due to proposed changes in the evaluation of aerodynamics. In the real 
world, vehicles are exposed to wind which increases the drag of the 
vehicle and in turn increases the power required to move the vehicle 
down the road. To more appropriately reflect the in-use aerodynamic 
performance of tractor-trailers, the agencies are proposing to input 
into Phase 2 GEM the wind averaged coefficient of drag instead of the 
no-wind (zero yaw) value used in Phase 1. The final key difference 
between Phase 1 and the proposed Phase 2 program includes a more 
realistic and improved simulation of the transmission in GEM, which 
could increase CO2 and fuel consumption relative to Phase 1.
    The agencies are proposing Phase 2 CO2 emissions and 
fuel consumption standards for the combination tractors that reflect 
reductions that can be achieved through improvements in the tractor's 
powertrain, aerodynamics, tires, and other vehicle systems. The 
agencies have analyzed the feasibility of achieving the proposed 
CO2 and fuel consumption standards, and have identified 
means of achieving the proposed standards that are technically feasible 
in the lead time afforded, economically practicable and cost-effective. 
EPA and NHTSA present the estimated costs and benefits of the proposed 
standards in Section III.D.2. In developing the proposed standards for 
Class 7 and 8 tractors, the agencies have evaluated the following:

 the current levels of emissions and fuel consumption
 the kinds of technologies that could be utilized by tractor 
and engine manufacturers to reduce emissions and fuel consumption from 
tractors and associated engines
 the necessary lead time
 the associated costs for the industry
 fuel savings for the consumer
 the magnitude of the CO2 and fuel savings that may 
be achieved

    The technologies on whose performance the proposed tractor 
standards are predicated include: Improvements in the engine, 
transmission, driveline, aerodynamic design, tire rolling resistance, 
other accessories of the tractor, and extended idle reduction 
technologies. These technologies, and other accessories of the tractor, 
are described in draft RIA Chapter 2.4. The agencies' evaluation shows 
that some of these technologies are available today, but have very low 
adoption rates on current vehicles, while others will require some lead 
time for development. EPA and NHTSA also present the estimated costs 
and benefits of the proposed Class 7 and 8 combination tractor 
standards in draft RIA Chapter 2.8 and 2.12, explaining as well the 
basis for the agencies' proposed stringency level.
    As explained below in Section III.D, EPA and NHTSA have determined 
that there would be sufficient lead time to introduce various tractor 
and engine technologies into the fleet starting in the 2021 model year 
and fully phasing in by the 2027 model year. This is consistent with 
NHTSA's statutory requirement to provide four full model years of 
regulatory lead time for standards. As was adopted in Phase 1, the 
agencies are proposing for Phase 2 that manufacturers may generate and 
use credits from Class 7 and 8 combination tractors to show compliance 
with the standards. This is discussed further in Section III.F.
    Based on our analysis, the 2027 model year standards for 
combination tractors and engines represent up to a 24 percent reduction 
in CO2 emissions and fuel consumption over a 2017 model year 
baseline tractor, as detailed in Section III.D.2. In considering the 
feasibility of vehicles to comply with the proposed standards over 
their useful lives, EPA also considered the potential for 
CO2 emissions to increase during the regulatory useful life 
of the product. As we discuss in Phase 1 and separately in the context 
of deterioration factor (DF) testing, we have concluded that 
CO2 emissions are likely to stay the same or actually 
decrease in-use compared to new certified configurations. In general, 
engine and vehicle friction decreases as products wear, leading to 
reduced parasitic losses and consequent lower CO2 emissions. 
Similarly, tire rolling resistance falls as tires wear due to the 
reduction in tread height. In the case of aerodynamic components, we 
project no change in performance through the regulatory life of the 
vehicle since there is essentially no change in their physical form as 
vehicles age. Similarly, weight reduction elements such as aluminum 
wheels are (evidently) not projected to increase in mass through time, 
and hence, we can conclude will not deteriorate with regard to 
CO2 performance in-use. Given all of these considerations, 
the agencies are confident in projecting that the tractor standards 
being proposed today would be technically feasible throughout the 
regulatory useful life of the program.
(2) Proposed Non-CO2 GHG Standards for Tractors
    EPA is also proposing standards to control non-CO2 GHG 
emissions from Class 7 and 8 combination tractors.
(a) N2O and CH4 Emissions
    The proposed heavy-duty engine standards for both N2O 
and CH4 as well as details of the proposed standards are 
included in the discussion in Section II.D.3 and II.D.4. No additional 
controls for N2O or CH4 emissions beyond those in 
the proposed HD Phase 2 engine standards are being considered for the 
tractor category.
(b) HFC Emissions
    Manufacturers can reduce hydrofluorocarbon (HFC) emissions from air 
conditioning (A/C) leakage emissions in two ways. First, they can

[[Page 40213]]

utilize leak-tight A/C system components. Second, manufacturers can 
largely eliminate the global warming impact of leakage emissions by 
adopting systems that use an alternative, low-Global Warming Potential 
(GWP) refrigerant, to replace the commonly used R-134a refrigerant. EPA 
proposes to address HFC emissions by maintaining the A/C leakage 
standards adopted in HD Phase 1 (see 40 CFR 1037.115). EPA believes the 
Phase 1 use of leak-tight components is at an appropriate level of 
stringency while maintaining the flexibility to produce the wide 
variety of A/C system configurations required in the tractor category. 
In addition, there currently are not any low GWP refrigerants approved 
for the heavy-duty vehicle sector. Without an alternative refrigerant 
approved for this sector, it is challenging to demonstrate feasibility 
to reduce the amount of leakage allowed under the HFC leakage standard. 
Please see Section I.F(1)(b) for a discussion related to alternative 
refrigerants.
(3) PM Emissions From APUs
    Auxiliary power units (APUs) can be used in lieu of operating the 
main engine during extended idle operations to provide climate control 
and power to the driver. APUs can reduce fuel consumption, 
NOX, HC, CH4, and CO2 emissions when 
compared to main engine idling.\120\ However, a potential unintended 
consequence of reducing CO2 emissions from combination 
tractors through the use of APUs during extended idle operation is an 
increase in PM emissions. Therefore, EPA is seeking comment on the need 
and appropriateness to further reduce PM emissions from APUs.
---------------------------------------------------------------------------

    \120\ U.S. EPA. Development of Emission Rates for Heavy-Duty 
Vehicles in the Motor Vehicle Emissions Simulator MOVES 2010. EPA-
420-B-12-049. August 2012.
---------------------------------------------------------------------------

    EPA conducted an analysis evaluating the potential impact on PM 
emissions due to an increase in APU adoption rates using MOVES. In this 
analysis, EPA assumed that these APUs emit criteria pollutants at the 
level of the EPA standard for this type of non-road diesel engines. 
Under this assumption, an APU would emit 1.8 grams PM per hour, 
assuming an extended idle load demand of 4.5 kW (6 hp).\121\ However, a 
2010 model year or newer tractor that uses its main engine to idle 
emits approximately 0.35 grams PM per hour.\122\ The results from these 
MOVES runs are shown below in Table III-2. These results show that an 
increase in use of APUs could lead to an overall increase in PM 
emissions if left uncontrolled. Column three labeled ``Proposed Program 
PM2.5 Emission Impact without Further PM Control (tons)'' 
shows the incremental increase in PM2.5 without further 
regulation of APU PM2.5 emissions.
---------------------------------------------------------------------------

    \121\ Tier 4, less-than-8 kW nonroad compression-ignition engine 
exhaust emissions standards assumed for APUs: http://www.epa.gov/otaq/standards/nonroad/nonroadci.htm.
    \122\ U.S. EPA. MOVES2014 Reports. Last accessed on May 1, 2015 
at http://www.epa.gov/otaq/models/moves/moves-reports.htm.

     Table III-2--Projected Impact of Increased Adoption of APUs in
                                 Phase 2
------------------------------------------------------------------------
                                                       Proposed program
                                Baseline HD vehicle   PM2.5\a\ emission
              CY                  PM2.5 emissions       impact without
                                       (tons)         further PM control
                                                            (tons)
------------------------------------------------------------------------
2035..........................               21,452                1,631
2050..........................               24,675                2,257
------------------------------------------------------------------------
Note:
\a\ Positive numbers mean emissions would increase from baseline to
  control case. PM2.5 from tire wear and brake wear are included.

    Since January 1, 2008, California ARB has prohibited the idling of 
sleeper cab tractors during periods of sleep and rest.\123\ The 
regulations apply additional requirements to diesel-fueled APUs on 
tractors equipped with 2007 model year or newer engines. Truck owners 
in California must either: (1) Fit the APU with an ARB verified Level 3 
particulate control device that achieves 85 percent reduction in 
particulate matter; or (2) have the APU exhaust plumbed into the 
vehicle's exhaust system upstream of the particulate matter 
aftertreatment device.\124\ Currently ARB includes four control devices 
that have been verified to meet the Level 3 p.m. requirements. These 
devices include HUSS Umwelttechnik GmbH's FS-MK Series Diesel 
Particulate filters, Impco Ecotrans Technologies' ClearSky Diesel 
Particulate Filter, Thermo King's Electric Regenerative Diesel 
Particulate Filter, and Proventia's Electronically Heated Diesel 
Particulate Filter. In addition, ARB has approved a Cummins integrated 
diesel-fueled APU and several fuel-fired heaters produced by Espar and 
Webasto.
---------------------------------------------------------------------------

    \123\ California Air Resources Board. Idle Reduction 
Technologies for Sleeper Berth Trucks. Last viewed on September 19, 
2014 at http://www.arb.ca.gov/msprog/cabcomfort/cabcomfort.htm.
    \124\ California Air Resources Board. Sec.  2485(c)(3)(A)(1).
---------------------------------------------------------------------------

    EPA conducted an evaluation of the impact of potentially requiring 
further PM control from APUs nationwide. As shown in Table III-2, EPA 
projects that the HD Phase 2 program as proposed (without additional PM 
controls) would increase PM2.5 emissions by 1,631 tons in 
2035 and 2,257 tons in 2050. The annual impact of a program to further 
control PM could lead to a reduction of PM2.5 emissions 
nationwide by 3,084 tons in 2035 and by 4,344 tons in 2050, as shown in 
Table III-3 the column labeled ``Net Impact on National 
PM2.5 Emission with Further PM Control of APUs (tons).''

[[Page 40214]]



                     Table III-3--Projected Impact of Further Control on PM2.5 Emissions \a\
----------------------------------------------------------------------------------------------------------------
                                                   Proposed HD phase 2  Proposed HD Phase 2     Net impact on
                               Baseline national     program national     Program National      national PM2.5
             CY                heavy-duty vehicle    PM2.5 Emissions      PM2.5 emissions       emission with
                                PM2.5 emissions     without Further PM    with further pm     further PM control
                                     (tons)           Control (tons)       control (tons)       of APUs (tons)
----------------------------------------------------------------------------------------------------------------
2035........................               21,452               23,083               19,999               -3,084
2050........................               24,675               26,932               22,588               -4,344
----------------------------------------------------------------------------------------------------------------
Note:
\a\ PM2.5 from tire wear and brake wear are included.

    EPA developed long-term cost projections for catalyzed diesel 
particulate filters (DPF) as part of the Nonroad Diesel Tier 4 
rulemaking. In that rulemaking, EPA estimated the DPF costs would add 
$580 to the cost of 150 horsepower engines (69 FR 39126, June 29, 
2004). On the other hand, ARB estimated the cost of retrofitting a 
diesel powered APU with a PM trap to be $2,000 in 2005.\125\ The costs 
of a DPF for an APU that provides less than 25 horsepower would be less 
than the projected cost of a 150 HP engine because the filter volume is 
in general proportional to the engine-out emissions and exhaust flow 
rate. Proventia is charging customers $2,240 for electronically heated 
DPF.\126\ EPA welcomes comments on cost estimates associated with DPF 
systems for APUs.
---------------------------------------------------------------------------

    \125\ California Air Resources Board. Staff Report: Initial 
Statement of Reasons; Notice of Public Hearing to Consider 
Requirements to Reduce Idling Emissions From New and In-Use Trucks, 
Beginning in 2008. September 1, 2005. Page 38. Last viewed on 
October 20, 2014 at http://www.arb.ca.gov/regact/hdvidle/isor.pdf.
    \126\ Proventia. Tripac Filter Kits. Last accessed on October 
21, 2014 at http://www.proventiafilters.com/purchase.html.
---------------------------------------------------------------------------

    EPA requests comments on the technical feasibility of diesel 
particulate filters ability to reduce PM emissions by 85 percent from 
non-road engines used to power APUs. EPA also requests comments on 
whether the technology costs outlined above are accurate, and if so, if 
projected reductions are appropriate taking into account cost, noise, 
safety, and energy factors. See CAA section 213(a)(4).
(4) Proposed Exclusions From the Phase 2 Tractor Standards
    As noted above, in Phase 1, the agencies adopted provisions to 
allow tractor manufacturers to reclassify certain tractors as 
vocational vehicles.\127\ The agencies propose in Phase 2 to continue 
to allow manufacturers to exclude certain vocational-types of tractors 
from the combination tractor standards and instead be subject to the 
vocational vehicle standards. However, the agencies propose to set 
unique standards for tractors used in heavy haul applications in Phase 
2. Details regarding the proposed heavy-haul standards are included 
below in Section II.D.3.
---------------------------------------------------------------------------

    \127\ See 40 CFR 1037.630.
---------------------------------------------------------------------------

    During the development of Phase 1, the agencies received multiple 
comments from several stakeholders supporting an approach for an 
alternative treatment of a subset of tractors because they were 
designed to operate at lower speeds, in stop and go traffic, and 
sometimes operate at higher weights than the typical line-haul tractor. 
These types of applications have limited potential for improvements in 
aerodynamic performance to reduce CO2 emissions and fuel 
consumption. Consistent with the agencies' approach in Phase 1, the 
agencies agree that these vocational tractors are operated differently 
than line-haul tractors and therefore fit more appropriately into the 
vocational vehicle category. However, we need to continue to ensure 
that only tractors that are truly vocational tractors are classified as 
such.\128\ A vehicle determined by the manufacturer to be a HHD 
vocational tractor would fall into one of the HHD vocational vehicle 
subcategories and be regulated as a vocational vehicle. Similarly, MHD 
tractors which the manufacturer chooses to reclassify as vocational 
tractors would be regulated as a MHD vocational vehicle. Specifically, 
the agencies are proposing to change the provisions in EPA's 40 CFR 
1037.630 and NHTSA's regulation at 49 CFR 523.2 and only allow the 
following two types of vocational tractors to be eligible for 
reclassification by the manufacturer:
---------------------------------------------------------------------------

    \128\ As a part of the end of the year compliance process, EPA 
and NHTSA verify manufacturer's production reports to avoid any 
abuse of the vocational tractor allowance.
---------------------------------------------------------------------------

    (1) Low-roof tractors intended for intra-city pickup and delivery, 
such as those that deliver bottled beverages to retail stores.
    (2) Tractors intended for off-road operation (including mixed 
service operation), such as those with reinforced frames and increased 
ground clearance.\129\
---------------------------------------------------------------------------

    \129\ See existing 40 CFR 1037.630(a)(1)(i) through (iii).
---------------------------------------------------------------------------

    Because the difference between some vocational tractors and line-
haul tractors is potentially somewhat subjective, we are also proposing 
to continue to limit the use of this provision to a rolling three year 
sales limit of 21,000 vocational tractors per manufacturer consistent 
with past production volumes of such vehicles. We propose to carry-over 
the existing three year sales limit with the recognition that heavy-
haul tractors would no longer be permitted to be treated as vocational 
vehicles (suggesting a lower volumetric cap could be appropriate) but 
that the heavy-duty market has improved since the development of the HD 
Phase 1 rule (suggesting the need for a higher sales cap). The agencies 
welcome comment on whether the proposed sales volume limit is set at an 
appropriate level looking into the future.
    Also in Phase 1, EPA determined that manufacturers that met the 
small business criteria specified in 13 CFR 121.201 for ``Heavy Duty 
Truck Manufacturing'' were not subject to the greenhouse gas emissions 
standards of 40 CFR 1037.106.\130\ The regulations required that 
qualifying manufacturers must notify the Designated Compliance Officer 
each model year before introducing the vehicles into commerce. The 
manufacturers are also required to label the vehicles to identify them 
as excluded vehicles. EPA and NHTSA are seeking comments on eliminating 
this provision for tractor manufacturers in the Phase 2 program. The 
agencies are aware of two second stage manufacturers building custom 
sleeper cab tractors. We could treat these vehicles in one of two ways. 
First, the vehicles may be considered as dromedary vehicles and 
therefore treated as vocational vehicles.\131\ Or the

[[Page 40215]]

agencies could provide provisions that stated if a manufacturer changed 
the cab, but not the frontal area of the vehicle, then it could retain 
the aerodynamic bin of the original tractor. We welcome comments on 
these considerations.
---------------------------------------------------------------------------

    \130\ See 40 CFR 1037.150(c).
    \131\ A dromedary is a box, deck, or plate mounted behind the 
tractor cab and forward of the fifth wheel on the frame of the power 
unit of a tractor-trailer combination to carry freight.
---------------------------------------------------------------------------

    EPA is proposing to not exempt glider kits from the Phase 2 GHG 
emission standards.\132\ Gliders and glider kits are exempt from 
NHTSA's Phase 1 fuel consumption standards. For EPA purposes, the 
CO2 provisions of Phase 1 exempted gliders and glider kits 
produced by small businesses but did not include such a blanket 
exemption for other glider kits.\133\ Thus, some gliders and glider 
kits are already subject to the requirement to obtain a vehicle 
certificate prior to introduction into commerce as a new vehicle. 
However, the agencies believe glider manufacturers may not understand 
how these regulations apply to them, resulting in a number of 
uncertified vehicles.
---------------------------------------------------------------------------

    \132\ Glider vehicles are new vehicles produced to accept 
rebuilt engines (or other used engines) along with used axles and/or 
transmissions. The common commercial term ``glider kit'' is used 
here primarily to refer to an assemblage of parts into which the 
used/rebuilt engine is installed.
    \133\ Rebuilt engines used in glider vehicles are subject to EPA 
criteria pollutant emission standards applicable for the model year 
of the engine. See 40 CFR 86.004-40 for requirements that apply for 
engine rebuilding. Under existing regulations, engines that remain 
in their certified configuration after rebuilding may continue to be 
used.
---------------------------------------------------------------------------

    EPA is concerned about adverse economic impacts on small businesses 
that assemble glider kits and glider vehicles. Therefore, EPA is 
proposing an option that would grandfather existing small businesses, 
but cap annual production based on their recent sales. EPA requests 
comment on whether any special provisions would be needed to 
accommodate glider kits. See Section XIV for additional discussion of 
the proposed requirements for glider vehicles.
    Similarly, NHTSA is considering including glider vehicles under its 
Phase 2 program. The agencies request comment on their respective 
considerations.
    We believe that the agencies potentially having different policies 
for glider kits and glider vehicles under the Phase 2 program would not 
result in problematic disharmony between the NHTSA and EPA programs, 
because of the small number of vehicles that would be involved. EPA 
believes that its proposed changes would result in the glider market 
returning to the pre-2007 levels, in which fewer than 1,000 glider 
vehicles would be produced in most years. Only non-exempt glider 
vehicles would be subject to different requirements under the NHTSA and 
EPA regulations. However, we believe that this is unlikely to exceed a 
few hundred vehicles in any year, which would be few enough not to 
result in any meaningful disharmony between the two agencies.
    With regard to NHTSA's safety authority over gliders, the agency 
notes that it has become increasingly aware of potential noncompliance 
with its regulations applicable to gliders. NHTSA has learned of 
manufacturers who are creating glider vehicles that are new vehicles 
under 49 CFR 571.7(e); however, the manufacturers are not certifying 
them and obtaining a new VIN as required. NHTSA plans to pursue 
enforcement actions as applicable against noncompliant manufacturers. 
In addition to enforcement actions, NHTSA may consider amending 49 CFR 
571.7(e) and related regulations as necessary. NHTSA believes 
manufacturers may not be using this regulation as originally intended.
(5) In-Use Standards
    Section 202(a)(1) of the CAA specifies that EPA is to propose 
emissions standards that are applicable for the useful life of the 
vehicle. The in-use Phase 2 standards that EPA is proposing would apply 
to individual vehicles and engines, just as EPA adopted for Phase 1. 
NHTSA is also proposing to use the same useful life mileage and years 
as EPA for Phase 2.
    EPA is also not proposing any changes to provisions requiring that 
the useful life for tractors with respect to CO2 emissions 
be equal to the respective useful life periods for criteria pollutants, 
as shown below in Table III-4. See 40 CFR 1037.106(e). EPA does not 
expect degradation of the technologies evaluated for Phase 2 in terms 
of CO2 emissions, therefore we propose no changes to the 
regulations describing compliance with GHG pollutants with regards to 
deterioration. See 40 CFR 1037.241. We welcome comments that highlight 
a need to change this approach.

                Table III-4--Tractor Useful Life Periods
------------------------------------------------------------------------
                                                      Years      Miles
------------------------------------------------------------------------
Class 7 Tractors..................................         10    185,000
Class 8 Tractors..................................         10    435,000
------------------------------------------------------------------------

D. Feasibility of the Proposed Tractor Standards

    This section describes the agencies' technical feasibility and cost 
analysis in greater detail. Further detail on all of these technologies 
can be found in the draft RIA Chapter 2.
    Class 7 and 8 tractors are used in combination with trailers to 
transport freight. The variation in the design of these tractors and 
their typical uses drive different technology solutions for each 
regulatory subcategory. As noted above, the agencies are proposing to 
continue the Phase 1 provisions that treat vocational tractors as 
vocational vehicles instead of as combination tractors, as noted in 
Section III.C. The focus of this section is on the feasibility of the 
proposed standards for combination tractors including the heavy-haul 
tractors, but not the vocational tractors.
    EPA and NHTSA collected information on the cost and effectiveness 
of fuel consumption and CO2 emission reducing technologies 
from several sources. The primary sources of information were the 
Southwest Research Institute evaluation of heavy-duty vehicle fuel 
efficiency and costs for NHTSA,\134\ the Department of Energy's 
SuperTruck Program,\135\ 2010 National Academy of Sciences report of 
Technologies and Approaches to Reducing the Fuel Consumption of Medium- 
and Heavy-Duty Vehicles,\136\ TIAX's assessment of technologies to 
support the NAS panel report,\137\ the analysis conducted by the 
Northeast States Center for a Clean Air Future, International Council 
on Clean Transportation, Southwest Research Institute and TIAX for 
reducing fuel consumption of heavy-duty long haul combination tractors 
(the NESCCAF/ICCT study),\138\ and the technology cost analysis 
conducted by ICF for EPA.\139\

[[Page 40216]]


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    \134\ Reinhart, T.E. (June 2015). Commercial Medium- and Heavy-
Duty Truck Fuel Efficiency Technology Study--Report #1. (Report No. 
DOT HS 812 146). Washington, DC: National Highway Traffic Safety 
Administration.
    \135\ U.S. Department of Energy. SuperTruck Initiative. 
Information available at http://energy.gov/eere/vehicles/vehicle-technologies-office.
    \136\ Committee to Assess Fuel Economy Technologies for Medium- 
and Heavy-Duty Vehicles; National Research Council; Transportation 
Research Board (2010). Technologies and Approaches to Reducing the 
Fuel Consumption of Medium- and Heavy-Duty Vehicles. (``The 2010 NAS 
Report'') Washington, DC, The National Academies Press.
    \137\ TIAX, LLC. ``Assessment of Fuel Economy Technologies for 
Medium- and Heavy-Duty Vehicles,'' Final Report to National Academy 
of Sciences, November 19, 2009.
    \138\ NESCCAF, ICCT, Southwest Research Institute, and TIAX. 
Reducing Heavy-Duty Long Haul Combination Truck Fuel Consumption and 
CO2 Emissions. October 2009.
    \139\ ICF International. ``Investigation of Costs for Strategies 
to Reduce Greenhouse Gas Emissions for Heavy-Duty On-Road 
Vehicles.'' July 2010. Docket Number EPA-HQ-OAR-2010-0162-0283.
---------------------------------------------------------------------------

(1) What technologies did the agencies consider to reduce the 
CO2 emissions and fuel consumption of combination tractors?
    Manufacturers can reduce CO2 emissions and fuel 
consumption of combination tractors through use of many technologies, 
including engine, drivetrain, aerodynamic, tire, extended idle, and 
weight reduction technologies. The agencies' determination of the 
feasibility of the proposed HD Phase 2 standards is based on our 
projection of the use of these technologies and an assessment of their 
effectiveness. We will also discuss other technologies that could 
potentially be used, such as vehicle speed limiters, although we are 
not basing the proposed standards on their use for the model years 
covered by this proposal, for various reasons discussed below.
    In this section we discuss generally the tractor and engine 
technologies that the agencies considered to improve performance of 
heavy-duty tractors, while Section III.D.2 discusses the baseline 
tractor definition and technology packages the agencies used to 
determine the proposed standard levels.
    Engine technologies: As discussed in Section II.D above, there are 
several engine technologies that can reduce fuel consumption of heavy-
duty tractors. These technologies include friction reduction, 
combustion system optimization, and Rankine cycle. These engine 
technologies would impact the Phase 2 vehicle results because the 
agencies propose that the manufacturers enter a fuel map into GEM.
    Aerodynamic technologies: There are opportunities to reduce 
aerodynamic drag from the tractor, but it is sometimes difficult to 
assess the benefit of individual aerodynamic features. Therefore, 
reducing aerodynamic drag requires optimizing of the entire system. The 
potential areas to reduce drag include all sides of the truck--front, 
sides, top, rear and bottom. The grill, bumper, and hood can be 
designed to minimize the pressure created by the front of the truck. 
Technologies such as aerodynamic mirrors and fuel tank fairings can 
reduce the surface area perpendicular to the wind and provide a smooth 
surface to minimize disruptions of the air flow. Roof fairings provide 
a transition to move the air smoothly over the tractor and trailer. 
Side extenders can minimize the air entrapped in the gap between the 
tractor and trailer. Lastly, underbelly treatments can manage the flow 
of air underneath the tractor. DOE has partnered with the heavy-duty 
industry to demonstrate vehicles that achieve a 50 percent improvement 
in freight efficiency. This SuperTruck program has led to significant 
advancements in the aerodynamics of combination tractor-trailers. The 
manufacturers' SuperTruck demonstration vehicles are achieving 
approximately 7 percent freight efficiency improvements over a 2010 MY 
baseline vehicle due to improvements in tractor aerodynamics.\140\ The 
2010 NAS Report on heavy-duty trucks found that aerodynamic 
improvements which yield 3 to 4 percent fuel consumption reduction or 6 
to 8 percent reduction in Cd values, beyond technologies used in 
today's SmartWay trucks are achievable.\141\
---------------------------------------------------------------------------

    \140\ Daimler Truck North America. SuperTruck Program Vehicle 
Project Review. June 19, 2014.
    \141\ See TIAX, Note 137, Page 4-40.
---------------------------------------------------------------------------

    Lower Rolling Resistance Tires: A tire's rolling resistance results 
from the tread compound material, the architecture and materials of the 
casing, tread design, the tire manufacturing process, and its operating 
conditions (surface, inflation pressure, speed, temperature, etc.). 
Differences in rolling resistance of up to 50 percent have been 
identified for tires designed to equip the same vehicle. Since 2007, 
SmartWay designated tractors have had steer tires with rolling 
resistance coefficients of less than 6.6 kg/metric ton for the steer 
tire and less than 7.0 kg/metric ton for the drive tire.\142\ Low 
rolling resistance (LRR) drive tires are currently offered in both dual 
assembly and wide-based single configurations. Wide based single tires 
can offer rolling resistance reduction along with improved aerodynamics 
and weight reduction. The lowest rolling resistance value submitted for 
2014MY GHG and fuel efficiency certification was 4.3 and 5.0 kg/metric 
ton for the steer and drive tires respectively.\143\
---------------------------------------------------------------------------

    \142\ Ibid.
    \143\ Memo to Docket. Coefficient of Rolling Resistance 
Certification Data. See Docket EPA-HQ-OAR-2014-0827.
---------------------------------------------------------------------------

    Weight Reduction: Reductions in vehicle mass lower fuel consumption 
and GHG emissions by decreasing the overall vehicle mass that is moved 
down the road. Weight reductions also increase vehicle payload 
capability which can allow additional tons to be carried by fewer 
trucks consuming less fuel and producing lower emissions on a ton-mile 
basis. We treated such weight reduction in two ways in Phase 1 to 
account for the fact that combination tractor-trailers weigh-out 
approximately one-third of the time and cube-out approximately two-
thirds of the time. Therefore in Phase 1 and also as proposed for Phase 
2, one-third of the weight reduction would be added payload in the 
denominator while two-thirds of the weight reduction is subtracted from 
the overall weight of the vehicle in GEM. See 76 FR 57153.
    In Phase 1, we reflected mass reductions for specific technology 
substitutions (e.g., installing aluminum wheels instead of steel 
wheels). These substitutions were included where we could with 
confidence verify the mass reduction information provided by the 
manufacturer. The agencies propose to expand the list of weight 
reduction components which can be input into GEM in order to provide 
the manufacturers with additional means to comply via GEM with the 
combination tractor standards and to further encourage reductions in 
vehicle weight. As in Phase 1, we recognize that there may be 
additional potential for weight reduction in new high strength steel 
components which combine the reduction due to the material substitution 
along with improvements in redesign, as evidenced by the studies done 
for light-duty vehicles.\144\ In the development of the high strength 
steel component weights, we are only assuming a reduction from material 
substitution and no weight reduction from redesign, since we do not 
have any data specific to redesign of heavy-duty components nor do we 
have a regulatory mechanism to differentiate between material 
substitution and improved design. Additional weight reduction would be 
evaluated as a potential off-cycle credit.
---------------------------------------------------------------------------

    \144\ American Iron and Steel Institute. ``A Cost Benefit 
Analysis Report to the North American Steel Industry on Improved 
Material and Powertrain Architectures for 21st Century Trucks.''
---------------------------------------------------------------------------

    Extended Idle Reduction: Auxiliary power units (APU), fuel operated 
heaters, battery supplied air conditioning, and thermal storage systems 
are among the technologies available today to reduce main engine 
extended idling from sleeper cabs. Each of these technologies reduces 
fuel consumption during idling from a truck without this equipment (the 
baseline) from approximately 0.8 gallons per hour (main engine idling 
fuel consumption rate) to approximately 0.2 gallons per hour for an 
APU.\145\ EPA and NHTSA agree with the TIAX assessment that a 5 percent 
reduction in overall fuel consumption reduction is achievable.\146\
---------------------------------------------------------------------------

    \145\ See the draft RIA Chapter 2.4.8 for details.
    \146\ See the 2010 NAS Report, Note 136, above, at 128.

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[[Page 40217]]

    Idle Reduction: Day cab tractors often idle while cargo is loaded 
or unloaded, as well as during the frequent stops that are inherent 
with driving in urban traffic conditions near cargo destinations. To 
recognize idle reduction technologies that reduce workday idling, the 
agencies have developed a new idle-only duty cycle that is proposed to 
be used in GEM. As discussed above in Section II.D, this new proposed 
certification test cycle would measure the amount of fuel saved and 
CO2 emissions reduced by two primary types of technologies: 
Neutral idle and stop-start. The proposed rules apply this test cycle 
only to vocational vehicles because these types of vehicles spend more 
time at idle than tractors. However, the agencies request comment on 
whether we should extend this vocational vehicle idle reduction 
approach to day cab tractors. Neutral idle would only be available for 
tractors using torque-converter automatic transmissions, and stop-start 
would be available for any tractor. Unlike the fixed numerical value in 
GEM for automatic engine shutdown systems to reduce overnight idling of 
combination tractors, this new idle reduction approach would result in 
different numerical values depending on user inputs. The required 
inputs and other details about this cycle, as it would apply to 
vocational vehicles, are described in the draft RIA Chapter 3. If we 
extended this approach to day cab tractors, we could set a fixed GEM 
composite cycle weighting factor at a value representative of the time 
spent at idle for a typical day cab tractor, possibly five percent. 
Under this approach, tractor manufacturers would be able to select GEM 
inputs that identify the presence of workday idle reduction 
technologies, and GEM would calculate the associated benefit due to 
these technologies, using this new idle-only cycle as described in the 
draft RIA Chapter 3.
    The agencies have also received a letter from the California Air 
Resources Board requesting consideration of credits for reducing solar 
loads. Solar reflective paints and solar control glazing technologies 
are briefly discussed in draft RIA Chapter 2.4.9.3. The agencies 
request comment on the Air Resources Board's letter and 
recommendations.\147\
---------------------------------------------------------------------------

    \147\ California Air Resources Board. Letter from Michael Carter 
to Matthew Spears dated December 3, 2014. Solar Control: Heavy-Duty 
Vehicles White Paper. Docket EPA-HA-OAR-2014-0827.
---------------------------------------------------------------------------

    Vehicle Speed Limiters: Fuel consumption and GHG emissions increase 
proportional to the square of vehicle speed. Therefore, lowering 
vehicle speeds can significantly reduce fuel consumption and GHG 
emissions. A vehicle speed limiter (VSL), which limits the vehicle's 
maximum speed, is another technology option for compliance that is 
already utilized today by some fleets (though the typical maximum speed 
setting is often higher than 65 mph).
    Downsized Engines and Downspeeding: As tractor manufacturers 
continue to reduce the losses due to vehicle loads, such as aerodynamic 
drag and rolling resistance, the amount of power required to move the 
vehicle decreases. In addition, engine manufacturers continue to 
improve the power density of heavy-duty engines through means such as 
reducing the engine friction due to smaller surface area. These two 
changes lead to the ability for truck purchasers to select lower 
displacement engines while maintaining the previous level of 
performance. Engine downsizing could be more effective if it is 
combined with the downspeeding assuming increased BMEP does not affect 
durability. The increased efficiency of the vehicle moves the operating 
points down to a lower load zone on a fuel map, which often moves the 
engine away from its sweet spot to a less efficient zone. In order to 
compensate for this loss, downspeeding allows the engine to run at a 
lower engine speed and move back to higher load zones, thus can 
slightly improve fuel efficiency. Reducing the engine size allows the 
vehicle operating points to move back to the sweet spot, thus further 
improving fuel efficiency. Engine downsizing can be accounted for as a 
vehicle technology through the use of the engine's fuel map in GEM.
    Transmission: As discussed in the 2010 NAS report, automatic (AT) 
and automated manual transmissions (AMT) may offer the ability to 
improve vehicle fuel consumption by optimizing gear selection compared 
to an average driver.\148\ However, as also noted in the report and in 
the supporting TIAX report, the improvement is very dependent on the 
driver of the truck, such that reductions ranged from 0 to 8 
percent.\149\ Well-trained drivers would be expected to perform as well 
or even better than an automatic transmission since the driver can see 
the road ahead and anticipate a changing stoplight or other road 
condition that neither an automatic nor automated manual transmission 
can anticipate. However, poorly-trained drivers that shift too 
frequently or not frequently enough to maintain optimum engine 
operating conditions could be expected to realize improved in-use fuel 
consumption by switching from a manual transmission to an automatic or 
automated manual transmission. As transmissions continue to evolve, we 
are now seeing in the European heavy-duty vehicle market the addition 
of dual clutch transmissions (DCT). DCTs operate similar to AMTs, but 
with two clutches so that the transmission can maintain engine speed 
during a shift which improves fuel efficiency. We believe there may be 
real benefits in reduced fuel consumption and GHG emissions through the 
adoption of dual clutch, automatic or automated manual transmission 
technology.
---------------------------------------------------------------------------

    \148\ Manual transmissions require the driver to shift the gears 
and manually engage and disengage the clutch. Automatic 
transmissions shift gears through computer controls and typically 
include a torque converter. An AMT operates similar to a manual 
transmission, except that an automated clutch actuator disengages 
and engages the drivetrain instead of a human driver. An AMT does 
not include a clutch pedal controllable by the driver or a torque 
converter.
    \149\ See TIAX, Note 137, above at 4-70.
---------------------------------------------------------------------------

    Low Friction Transmission, Axle, and Wheel Bearing Lubricants: The 
2010 NAS report assessed low friction lubricants for the drivetrain as 
providing a 1 percent improvement in fuel consumption based on fleet 
testing.\150\ A field trial of European medium-duty trucks found an 
average fuel consumption improvement of 1.8 percent using SAE 5W-30 
engine oil, SAE 75W90 axle oil and SAE 75W80 transmission oil when 
compared to SAE 15W40 engine oil and SAE 90W axle oil, and SAE 80W 
transmission oil.\151\ The light-duty 2012-16 MY vehicle rule and the 
pickup truck portion of this program estimate that low friction 
lubricants can have an effectiveness value between 0 and 1 percent 
compared to traditional lubricants.
---------------------------------------------------------------------------

    \150\ See the 2010 NAS Report, Note 136, page 67.
    \151\ Green, D.A., et al. ``The Effect of Engine, Axle, and 
Transmission Lubricant, and Operating Conditions on Heavy Duty 
Diesel Fuel Economy. Part 1: Measurements.'' SAE 2011-01-2129. SAE 
International Journal of Fuels and Lubricants. January 2012.
---------------------------------------------------------------------------

    Drivetrain: Most tractors today have three axles--a steer axle and 
two rear drive axles, and are commonly referred to as 6x4 tractors. 
Manufacturers offer 6x2 tractors that include one rear drive axle and 
one rear non-driving axle. The 6x2 tractors offer three distinct 
benefits. First, the non-driving rear axle does not have internal 
friction and therefore reduces the overall parasitic losses in the 
drivetrain. In addition, the 6x2 configuration typically weighs 
approximately 300 to 400 lbs less than

[[Page 40218]]

a 6x4 configuration.\152\ Finally, the 6x2 typically costs less or is 
cost neutral when compared to a 6x4 tractor. Sources cite the 
effectiveness of 6x2 axles at between 1 and 3 percent.\153\ Similarly, 
with the increased use of double and triple trailers, which reduce the 
weight on the tractor axles when compared to a single trailer, 
manufacturers offer 4x2 axle configurations. The 4x2 axle configuration 
would have as good as or better fuel efficiency performance than a 6x2.
---------------------------------------------------------------------------

    \152\ North American Council for Freight Efficiency. 
''Confidence Findings on the Potential of 6x2 Axles.'' 2014. Page 
16.
    \153\ Reinhart, T.E. (June 2015). Commercial Medium- and Heavy-
Duty Truck Fuel Efficiency Technology Study--Report #1. (Report No. 
DOT HS 812 146). Washington, DC: National Highway Traffic Safety 
Administration.
---------------------------------------------------------------------------

    Accessory Improvements: Parasitic losses from the engine come from 
many systems, including the water pump, oil pump, and power steering 
pump. Reductions in parasitic losses are one of the areas being 
developed under the DOE SuperTruck program. As presented in the DOE 
Merit reviews, Navistar stated that they demonstrated a 0.45 percent 
reduction in fuel consumption through water pump improvements and 0.3 
percent through oil pump improvements compared to a current engine. In 
addition, Navistar showed a 0.9 percent benefit for a variable speed 
water pump and variable displacement oil pump. Detroit Diesel reports a 
0.5 percent coming from improved water pump efficiency.\154\ It should 
be noted that water pump improvements include both pump efficiency 
improvement and variable speed or on/off controls. Lube pump 
improvements are primarily achieved using variable displacement pumps 
and may also include efficiency improvement. All of these results shown 
in this paragraph are demonstrated through the DOE SuperTruck program 
at single operating point on the engine map, and therefore the overall 
expected reduction of these technologies is less than the single point 
result.
---------------------------------------------------------------------------

    \154\ See the draft RIA Chapter 2.4 for details.
---------------------------------------------------------------------------

    Intelligent Controls: Skilled drivers know how to control a vehicle 
to obtain maximum fuel efficiency by, among other things, considering 
road terrain. For example, the driver may allow the vehicle to slow 
down below the target speed on an uphill and allow it to go over the 
target speed when going downhill, to essentially smooth out the engine 
demand. Electronic controls can be developed to essentially mimic this 
activity. The agencies propose to provide a 2 percent reduction in fuel 
consumption and CO2 emissions for vehicles configured with 
intelligent controls, such as predictive cruise control.
    Automatic Tire Inflation Systems: Proper tire inflation is critical 
to maintaining proper stress distribution in the tire, which reduces 
heat loss and rolling resistance. Tires with reduced inflation pressure 
exhibit a larger footprint on the road, more sidewall flexing and tread 
shearing, and therefore, have greater rolling resistance than a tire 
operating at its optimal inflation pressure. Bridgestone tested the 
effect of inflation pressure and found a 2 percent variation in fuel 
consumption over a 40 psi range.\155\ Generally, a 10 psi reduction in 
overall tire inflation results in about a 1 percent reduction in fuel 
economy.\156\ To achieve the intended fuel efficiency benefits of low 
rolling resistance tires, it is critical that tires are maintained at 
the proper inflation pressure.
---------------------------------------------------------------------------

    \155\ Bridgestone Tires. Real Questions, Real Answers. http://www.bridgestonetrucktires.com/us_eng/real/magazines/ra_special-edit_4/ra_special4_fuel-tires.asp.
    \156\ ``Factors Affecting Truck Fuel Economy,'' Goodyear, Radial 
Truck and Retread Service Manual. Accessed February 16, 2010 at 
http://www.goodyear.com/truck/pdf/radialretserv/Retread_S9_V.pdf.
---------------------------------------------------------------------------

    Proper tire inflation pressure can be maintained with a rigorous 
tire inspection and maintenance program or with the use of tire 
pressure and inflation systems. According to a study conducted by FMCSA 
in 2003, about 1 in 5 tractors/trucks is operating with 1 or more tires 
underinflated by at least 20 psi.\157\ A 2011 FMCSA study estimated 
underinflation accounts for one service call per year and increases 
tire procurement costs 10 to 13 percent. The study found that total 
operating costs can increase by $600 to $800 per year due to 
underinflation.\158\ A recent study by The North American Council on 
Freight Efficiency, found that adoption of tire pressure monitoring 
systems is increasing. It also found that reliability and durability of 
commercially available tire pressure systems are good and early issues 
with the systems have been addressed.\159\ These automatic tire 
inflation systems monitor tire pressure and also automatically keep 
tires inflated to a specific level. The agencies propose to provide a 1 
percent CO2 and fuel consumption reduction value for 
tractors with automatic tire inflation systems installed.
---------------------------------------------------------------------------

    \157\ American Trucking Association. Tire Pressure Monitoring 
and Inflation Maintenance. June 2010. Page 3. Last accessed on 
December 15, 2014 at http://www.trucking.org/ATA%20Docs/About/Organization/TMC/Documents/Position%20Papers/Study%20Group%20Information%20Reports/Tire%20Pressure%20Monitoring%20and%20Inflation%20Maintenance%E2%80%94TMC%20I.R.%202010-2.pdf.
    \158\ TMC Future Truck Committee Presentation ``FMCSA Tire 
Pressure Monitoring Field Operational Test Results,'' February 8, 
2011.
    \159\ North American Council for Freight Efficiency, ``Tire 
Pressure Systems,'' 2013.
---------------------------------------------------------------------------

    Tire pressure monitoring systems notify the operator of tire 
pressure, but require the operator to manually inflate the tires to the 
optimum pressure. Because of the dependence on the operator's action, 
the agencies are not proposing to provide a reduction value for tire 
pressure monitoring systems. We request comment on this approach and 
seek data from those that support a reduction value be assigned to tire 
pressure monitoring systems.
    Hybrid: Hybrid powertrain development in Class 7 and 8 tractors has 
been limited to a few manufacturer demonstration vehicles to date. One 
of the key benefit opportunities for fuel consumption reduction with 
hybrids is less fuel consumption when a vehicle is idling, but the 
standard is already premised on use of extended idle reduction so use 
of hybrid technology would duplicate many of the same emission 
reductions attributable to extended idle reduction. NAS estimated that 
hybrid systems would cost approximately $25,000 per tractor in the 2015 
through the 2020 time frame and provide a potential fuel consumption 
reduction of 10 percent, of which 6 percent is idle reduction which can 
be achieved (less expensively) through the use of other idle reduction 
technologies.\160\ The limited reduction potential outside of idle 
reduction for Class 8 sleeper cab tractors is due to the mostly highway 
operation and limited start-stop operation. Due to the high cost and 
limited benefit during the model years at issue in this action (as well 
as issues regarding sufficiency of lead time (see Section III.D.2 
below), the agencies are not including hybrids in assessing standard 
stringency (or as an input to GEM).
---------------------------------------------------------------------------

    \160\ See the 2010 NAS Report, Note 136, page 128.
---------------------------------------------------------------------------

    Management: The 2010 NAS report noted many operational 
opportunities to reduce fuel consumption, such as driver training and 
route optimization. The agencies have included discussion of several of 
these strategies in draft RIA Chapter 2, but are not using these 
approaches or technologies in the standard setting process. The 
agencies are looking to other resources, such as EPA's SmartWay 
Transport Partnership and regulations that could potentially be 
promulgated by the Federal Highway Administration and the Federal Motor 
Carrier Safety Administration, to continue to encourage the development 
and utilization of these approaches.

[[Page 40219]]

(2) Projected Technology Effectiveness and Cost
    EPA and NHTSA project that CO2 emissions and fuel 
consumption reductions can be feasibly and cost-effectively met through 
technological improvements in several areas. The agencies evaluated 
each technology and estimated the most appropriate adoption rate of 
technology into each tractor subcategory. The next sections describe 
the baseline vehicle configuration, the effectiveness of the individual 
technologies, the costs of the technologies, the projected adoption 
rates of the technologies into the regulatory subcategories, and 
finally the derivation of the proposed standards.
    The agencies propose Phase 2 standards that project by 2027, all 
high-roof tractors would have aerodynamic performance equal to or 
better today's SmartWay performance--which represents the best of 
today's technology. This would equate to having 40 percent of new high 
roof sleeper cabs in 2027 complying with the current best practices and 
60 percent of the new high-roof sleeper cab tractors sold in 2027 
having better aerodynamic performance than the best tractors available 
today. For tire rolling resistance, we premised the proposed standards 
on the assumption that nearly all tires in 2027 would have rolling 
resistance equal to or superior to tires meeting today's SmartWay 
designation. As discussed in Section II.D, the agencies assume the 
proposed 2027 MY engines would achieve an additional 4 percent 
improvement over Phase 1 engines and we project would include 15 
percent of waste heat recovery (WHR) and many other advanced engine 
technologies. In addition, we are proposing standards that project 
improvements to nearly all of today's transmissions, incorporation of 
extended idle reduction technologies on 90 percent of sleeper cabs, and 
significant adoption of other types of technologies such as predictive 
cruise control and automatic tire inflation systems.
    In addition to the high cost and limited utility of hybrids for 
many tractor drive cycles noted above, the agencies believe that hybrid 
powertrains systems for tractors may not be sufficiently developed and 
the necessary manufacturing capacity put in place to base a standard on 
any significant volume of hybrid tractors. Unlike hybrids for 
vocational vehicles and light-duty vehicles, the agencies are not aware 
of any full hybrid systems currently developed for long haul tractor 
applications. To date, hybrid systems for tractors have been primarily 
focused on idle shutdown technologies and not on the broader energy 
storage and recovery systems necessary to achieve reductions over 
typical vehicle drive cycles. The proposed standards reflect the 
potential for idle shutdown technologies through GEM. Further as 
highlighted by the 2010 NAS report, the agencies do believe that full 
hybrid powertrains may have the potential in the longer term to provide 
significant improvements in tractor fuel efficiency and to greenhouse 
gas emission reductions. However, due to the high cost, limited benefit 
during highway driving, and lacking any existing systems or 
manufacturing base, we cannot conclude with certainty, absent 
additional information, that such technology would be available for 
tractors in the 2021-2027 timeframe. However the agencies welcome 
comment from industry and others on their projected timeline for 
deployment of hybrid powertrains for tractor applications.
(a) Tractor Baselines for Costs and Effectiveness
    The fuel efficiency and CO2 emissions of combination 
tractors vary depending on the configuration of the tractor. Many 
aspects of the tractor impact its performance, including the engine, 
transmission, drive axle, aerodynamics, and rolling resistance. For 
each subcategory, the agencies selected a theoretical tractor to 
represent the average 2017 model year tractor that meets the Phase 1 
standards (see 76 FR 57212, September 15, 2011). These tractors are 
used as baselines from which to evaluate costs and effectiveness of 
additional technologies and standards. The specific attributes of each 
tractor subcategory are listed below in Table III-5. Using these 
values, the agencies assessed the CO2 emissions and fuel 
consumption performance of the proposed baseline tractors using the 
proposed version of Phase 2 GEM. The results of these simulations are 
shown below in Table III-6.
    As noted earlier, the Phase 1 2017 model year tractor standards and 
the baseline 2017 model year tractor results are not directly 
comparable. The same set of aerodynamic and tire rolling resistance 
technologies were used in both setting the Phase 1 standards and 
determining the baseline of the Phase 2 tractors. However, there are 
several aspects that differ. First, a new version of GEM was developed 
and validated to provide additional capabilities, including more 
refined modeling of transmissions and engines. Second, the 
determination of the proposed HD Phase 2 CdA value takes into account a 
revised test procedure, a new standard reference trailer, and wind 
averaged drag as discussed below in Section III.E. In addition, the 
proposed HD Phase 2 version of GEM includes road grade in the 55 mph 
and 65 mph highway cycles, as discussed below in Section III.E. 
Finally, the agencies assessed the current level of automatic engine 
shutdown and idle reduction technologies used by the tractor 
manufacturers to comply with the 2014 model year CO2 and 
fuel consumption standards. To date, the manufacturers are meeting the 
2014 model year standards without the use of this technology. 
Therefore, in this proposal the agencies reverted back to the baseline 
APU adoption rate of 30 percent, the value used in the Phase 1 
baseline.

[[Page 40220]]



                         Table III-5--GEM Inputs for the Baseline Class 7 and 8 Tractor
----------------------------------------------------------------------------------------------------------------
               Class 7                                                  Class 8
----------------------------------------------------------------------------------------------------------------
               Day cab                                Day cab                             Sleeper cab
----------------------------------------------------------------------------------------------------------------
  Low roof     Mid roof    High roof     Low roof     Mid roof    High roof    Low roof    Mid roof    High roof
----------------------------------------------------------------------------------------------------------------
                                                     Engine
----------------------------------------------------------------------------------------------------------------
2017 MY 11L  2017 MY 11L  2017 MY 11L  2017 MY 15L  2017 MY 15L  2017 MY 15L    2017 MY     2017 MY     2017 MY
 Engine 350  Engine 350   Engine 350   Engine 455   Engine 455   Engine 455   15L Engine  15L Engine  15L Engine
     HP              HP           HP           HP           HP           HP      455 HP      455 HP      455 HP
----------------------------------------------------------------------------------------------------------------
                                           Aerodynamics (CdA in m\2\)
----------------------------------------------------------------------------------------------------------------
      5.00         6.40         6.42         5.00         6.40         6.42        4.95        6.35        6.22
----------------------------------------------------------------------------------------------------------------
                                       Steer Tires (CRR in kg/metric ton)
----------------------------------------------------------------------------------------------------------------
      6.99         6.99         6.87         6.99         6.99         6.87        6.87        6.87        6.54
----------------------------------------------------------------------------------------------------------------
                                       Drive Tires (CRR in kg/metric ton)
----------------------------------------------------------------------------------------------------------------
      7.38         7.38         7.26         7.38         7.38         7.26        7.26        7.26        6.92
----------------------------------------------------------------------------------------------------------------
                                      Extended Idle Reduction Adoption Rate
----------------------------------------------------------------------------------------------------------------
       N/A          N/A          N/A          N/A          N/A          N/A         30%         30%         30%
----------------------------------------------------------------------------------------------------------------
                                   Transmission = 10 Speed Manual Transmission
----------------------------------------------------------------------------------------------------------------
                    Gear Ratios = 12.8, 9.25, 6.76, 4.90, 3.58, 2.61, 1.89, 1.38, 1.00, 0.73
----------------------------------------------------------------------------------------------------------------
                                             Drive Axle Ratio = 3.70
----------------------------------------------------------------------------------------------------------------


                                     Table III-6--Class 7 and 8 Tractor Baseline CO2 Emissions and Fuel Consumption
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Class 7                                           Class 8
                                                      --------------------------------------------------------------------------------------------------
                                                                   Day cab                          Day cab                        Sleeper cab
                                                      --------------------------------------------------------------------------------------------------
                                                        Low roof   Mid roof  High roof   Low roof   Mid roof  High roof   Low roof   Mid roof  High roof
--------------------------------------------------------------------------------------------------------------------------------------------------------
CO2 (grams CO2/ton-mile).............................     107        118        121         86         93         95         79         87         88
Fuel Consumption (gal/1,000 ton-mile)................      10.5       11.6       11.9        8.4        9.1        9.3        7.8        8.5        8.6
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The fuel consumption and CO2 emissions in the baseline 
described above remains the same over time with no assumed improvements 
after 2017, absent a Phase 2 regulation. An alternative baseline was 
also evaluated by the agencies in which there is a continuing uptake of 
technologies in the tractor market that reduce fuel consumption and 
CO2 emissions absent a Phase 2 regulation. This alternative 
baseline, referred to as the more dynamic baseline, was developed to 
estimate the effect of market pressures and non-regulatory government 
initiatives to improve tractor fuel consumption. The more dynamic 
baseline assumes that the significant level of research funded and 
conducted by the Federal government, industry, academia and other 
organizations will, in the future, result the adoption of some 
technologies beyond the levels required to comply with Phase 1 
standards. One example of such research is the Department of Energy 
Super Truck program \161\ which has a goal of demonstrating cost-
effective measures to improve the efficiency of Class 8 long-haul 
freight trucks by 50 percent by 2015. The more dynamic baseline also 
assumes that manufacturers will not cease offering fuel efficiency 
improving technologies that currently have significant market 
penetration, such as automated manual transmissions. The baselines (one 
for each of the nine tractor types) are characterized by fuel 
consumption and CO2 emissions that gradually decrease 
between 2019 and 2028. In 2028, the fuel consumption for the 
alternative tractor baselines is approximately 4.0 percent lower than 
those shown in Table III-6. This results from the assumed introduction 
of aerodynamic technologies such as down exhaust, underbody airflow 
treatment in addition to tires with lower rolling resistance. The 
assumed introduction of these technologies reduces the CdA of the 
baseline tractors and CRR of the tractor tires. To take one example, 
the CdA for baseline high roof sleeper cabs in Table III-5 is 6.22 
(m\2\) in 2018. In 2028, the CdA of a high roof sleeper cab would be 
assumed to still be 6.22 m\2\ in the baseline case outlined above. 
Alternatively, in the dynamic baseline, the CdA for high roof sleeper 
cabs is 5.61 (m\2\) in 2028 due to assumed market penetration of 
technologies absent the Phase 2 regulation. The dynamic baseline 
analysis is discussed in more detail in draft RIA Chapter 11.
---------------------------------------------------------------------------

    \161\ U.S. Department of Energy. ``SuperTruck Making Leaps in 
Fuel Efficiency.'' 2014. Last accessed on May 10, 2015 at http://energy.gov/eere/articles/supertruck-making-leaps-fuel-efficiency.

---------------------------------------------------------------------------

[[Page 40221]]

(b) Tractor Technology Packages
    The agencies' assessment of the proposed technology effectiveness 
was developed through the use of the GEM in coordination with modeling 
conducted by Southwest Research Institute. The agencies developed the 
proposed standards through a three-step process, similar to the 
approach used in Phase 1. First, the agencies developed technology 
performance characteristics for each technology, as described below. 
Each technology is associated with an input parameter which in turn 
would be used as an input to the Phase 2 GEM simulation tool and its 
effectiveness thereby modeled. The performance levels for the range of 
Class 7 and 8 tractor aerodynamic packages and vehicle technologies are 
described below in Table III-7. Second, the agencies combined the 
technology performance levels with a projected technology adoption rate 
to determine the GEM inputs used to set the stringency of the proposed 
standards. Third, the agencies input these parameters into Phase 2 GEM 
and used the output to determine the proposed CO2 emissions 
and fuel consumption levels. All percentage improvements noted below 
are over the 2017 baseline tractor.
(i) Engine Improvements
    There are several technologies that could be used to improve the 
efficiency of diesel engines used in tractors. Details of the engine 
technologies, adoption rates, and overall fuel consumption and 
CO2 emission reductions are included in Section II.D. The 
proposed heavy-duty tractor engine standards would lead to a 1.5 
percent reduction in 2021MY, a 3.5 percent reduction in 2024MY, and a 4 
percent reduction in 2027MY. These reductions would show up in the fuel 
map used in GEM.
(ii) Aerodynamics
    The aerodynamic packages are categorized as Bin I, Bin II, Bin III, 
Bin IV, Bin V, Bin VI, or Bin VII based on the wind averaged drag 
aerodynamic performance determined through testing conducted by the 
manufacturer. A more complete description of these aerodynamic packages 
is included in Chapter 2 of the draft RIA. In general, the proposed CdA 
values for each package and tractor subcategory were developed through 
EPA's coastdown testing of tractor-trailer combinations, the 2010 NAS 
report, and SAE papers.
(iii) Tire Rolling Resistance
    The proposed rolling resistance coefficient target for Phase 2 was 
developed from SmartWay's tire testing to develop the SmartWay 
certification, testing a selection of tractor tires as part of the 
Phase 1 and Phase 2 programs, and from 2014 MY certification data. Even 
though the coefficient of tire rolling resistance comes in a range of 
values, to analyze this range, the tire performance was evaluated at 
four levels for both steer and drive tires, as determined by the 
agencies. The four levels are the baseline (average) from 2010, Level I 
and Level 2 from Phase 1, and Level 3 that achieves an additional 25 
percent improvement over Level 2. The Level 1 rolling resistance 
performance represents the threshold used to develop SmartWay 
designated tires for long haul tractors. The Level 2 threshold 
represents an incremental step for improvements beyond today's SmartWay 
level and represents the best in class rolling resistance of the tires 
we tested. The Level 3 values represent the long-term rolling 
resistance value that the agencies predicts could be achieved in the 
2025 timeframe. Given the multiple year phase-in of the standards, the 
agencies expect that tire manufacturers will continue to respond to 
demand for more efficient tires and will offer increasing numbers of 
tire models with rolling resistance values significantly better than 
today's typical low rolling resistance tires. The tire rolling 
resistance level assumed to meet the 2017 MY Phase 1 standard high roof 
sleeper cab is considered to be a weighted average of 10 percent 
baseline rolling resistance, 70 percent Level 1, and 20 percent Level 
2. The tire rolling resistance to meet the 2017MY Phase 1 standards for 
the high roof day cab, low roof sleeper cab, and mid roof sleeper cab 
includes 30 percent baseline, 60 percent Level 1 and 10 percent Level 
2. Finally, the low roof day cab 2017MY standard can be met with a 
weighted average rolling resistance consisting of 40 percent baseline, 
50 percent Level 1, and 10 percent Level 2.
(iv) Idle Reduction
    The benefits for the extended idle reductions were developed from 
literature, SmartWay work, and the 2010 NAS report. Additional details 
regarding the comments and calculations are included in draft RIA 
Section 2.4.
(v) Transmission
    The benefits for automated manual, automatic, and dual clutch 
transmissions were developed from literature and from simulation 
modeling conducted by Southwest Research Institute. The benefit of 
these transmissions is proposed to be set to a two percent improvement 
over a manual transmission due to the automation of the gear shifting.
(vi) Drivetrain
    The reduction in friction due to low viscosity axle lubricants is 
set to 0.5 percent. 6x4 and 4x2 axle configurations lead to a 2.5 
percent improvement in vehicle efficiency. Downspeeding would be as 
demonstrated through the Phase 2 GEM inputs of transmission gear ratio, 
drive axle ratio, and tire diameter. Downspeeding is projected to 
improve the fuel consumption by 1.8 percent.
(vii) Accessories and Other Technologies
    Compared to 2017MY air conditioners, air conditioners with improved 
efficiency compressors will reduce CO2 emissions by 0.5 
percent. Improvements in accessories, such as power steering, can lead 
to an efficiency improvement of 1 percent over the 2017MY baseline. 
Based on literature information, intelligent controls such as 
predictive cruise control will reduce CO2 emissions by 2 
percent while automatic tire inflation systems improve fuel consumption 
by 1 percent by keeping tire rolling resistance to its optimum based on 
inflation pressure.
(viii) Weight Reduction
    The weight reductions were developed from tire manufacturer 
information, the Aluminum Association, the Department of Energy, SABIC 
and TIAX, as discussed above in Section II.B.3.e.
(ix) Vehicle Speed Limiter
    The agencies did not consider the availability of vehicle speed 
limiter technology in setting the Phase 1 stringency levels, and again 
did not consider the availability of the technology in developing 
regulatory alternatives for Phase 2. However, as described in more 
detail above, speed limiters could be an effective means for achieving 
compliance, if employed on a voluntary basis.
(x) Summary of Technology Performance
    Table III-7 describes the performance levels for the range of Class 
7 and 8 tractor vehicle technologies.

[[Page 40222]]



                                                     Table III-7--Proposed Phase 2 Technology Inputs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Class 7                                           Class 8
                                                      --------------------------------------------------------------------------------------------------
                                                                   Day cab                          Day cab                        Sleeper cab
                                                      --------------------------------------------------------------------------------------------------
                                                        Low roof   Mid roof  High roof   Low roof   Mid roof  High roof   Low roof   Mid roof  High roof
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Engine
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         2021MY     2021MY     2021MY     2021MY     2021MY     2021MY     2021MY     2021MY     2021MY
                                                          11L        11L        11L        15L        15L        15L        15L        15L        15L
                                                         Engine     Engine     Engine     Engine     Engine     Engine     Engine     Engine     Engine
                                                         350 HP     350 HP     350 HP     455 HP     455 HP     455 HP     455 HP     455 HP     455 HP
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Aerodynamics (CdA in m\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bin I................................................        5.3        6.7        7.6        5.3        6.7        7.6        5.3        6.7        7.4
Bin II...............................................        4.8        6.2        7.1        4.8        6.2        7.1        4.8        6.2        6.9
Bin III..............................................        4.3        5.7        6.5        4.3        5.7        6.5        4.3        5.7        6.3
Bin IV...............................................        4.0        5.4        5.8        4.0        5.4        5.8        4.0        5.4        5.6
Bin V................................................        N/A        N/A        5.3        N/A        N/A        5.3        N/A        N/A        5.1
Bin VI...............................................        N/A        N/A        4.9        N/A        N/A        4.9        N/A        N/A        4.7
Bin VII..............................................        N/A        N/A        4.5        N/A        N/A        4.5        N/A        N/A        4.3
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           Steer Tires (CRR in kg/metric ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Base.................................................        7.8        7.8        7.8        7.8        7.8        7.8        7.8        7.8        7.8
Level 1..............................................        6.6        6.6        6.6        6.6        6.6        6.6        6.6        6.6        6.6
Level 2..............................................        5.7        5.7        5.7        5.7        5.7        5.7        5.7        5.7        5.7
Level 3..............................................        4.3        4.3        4.3        4.3        4.3        4.3        4.3        4.3        4.3
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           Drive Tires (CRR in kg/metric ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Base.................................................        8.2        8.2        8.2        8.2        8.2        8.2        8.2        8.2        8.2
Level 1..............................................        7.0        7.0        7.0        7.0        7.0        7.0        7.0        7.0        7.0
Level 2..............................................        6.0        6.0        6.0        6.0        6.0        6.0        6.0        6.0        6.0
Level 3..............................................        4.5        4.5        4.5        4.5        4.5        4.5        4.5        4.5        4.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Idle Reduction (% reduction)
--------------------------------------------------------------------------------------------------------------------------------------------------------
APU..................................................        N/A        N/A        N/A        N/A        N/A        N/A         5%         5%         5%
Other................................................        N/A        N/A        N/A        N/A        N/A        N/A         7%         7%         7%
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Transmission Type (% reduction)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Manual...............................................         0%         0%         0%         0%         0%         0%         0%         0%         0%
AMT..................................................          2          2          2          2          2          2          2          2          2
Auto.................................................          2          2          2          2          2          2          2          2          2
Dual Clutch..........................................          2          2          2          2          2          2          2          2          2
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Driveline (% reduction)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Axle Lubricant.......................................       0.5%       0.5%       0.5%       0.5%       0.5%       0.5%       0.5%       0.5%       0.5%
6x2 or 4x2 Axle......................................        2.5        2.5        2.5        2.5        2.5        2.5        2.5        2.5        2.5
Downspeed............................................        1.8        1.8        1.8        1.8        1.8        1.8        1.8        1.8        1.8
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          Accessory Improvements (% reduction)
--------------------------------------------------------------------------------------------------------------------------------------------------------
A/C..................................................       0.5%       0.5%       0.5%       0.5%       0.5%       0.5%       0.5%       0.5%       0.5%
Electric Access......................................          1          1          1          1          1          1          1          1          1
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Other Technologies (% reduction)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Predictive Cruise Control............................         2%         2%         2%         2%         2%         2%         2%         2%         2%
Automated Tire Inflation System......................          1          1          1          1          1          1          1          1          1
--------------------------------------------------------------------------------------------------------------------------------------------------------

(c) Tractor Technology Adoption Rates
    As explained above, tractor manufacturers often introduce major 
product changes together, as a package. In this manner the 
manufacturers can optimize their available resources, including 
engineering, development, manufacturing and marketing activities to 
create a product with multiple new features. In addition, manufacturers 
recognize that a truck design will need to remain competitive over the 
intended life of the design and meet future regulatory requirements. In 
some limited cases, manufacturers may implement an individual 
technology outside of a vehicle's redesign cycle.
    With respect to the levels of technology adoption used to develop 
the proposed HD Phase 2 standards, NHTSA and EPA established technology

[[Page 40223]]

adoption constraints. The first type of constraint was established 
based on the application of fuel consumption and CO2 
emission reduction technologies into the different types of tractors. 
For example, extended idle reduction technologies are limited to Class 
8 sleeper cabs using the reasonable assumption that day cabs are not 
used for overnight hoteling. A second type of constraint was applied to 
most other technologies and limited their adoption based on factors 
reflecting the real world operating conditions that some combination 
tractors encounter. This second type of constraint was applied to the 
aerodynamic, tire, powertrain, and vehicle speed limiter technologies.
    Table III-8 and Table III-10, specify the adoption rates that EPA 
and NHTSA used to develop the proposed standards. The agencies welcome 
comments on these adoption rates.
    NHTSA and EPA believe that within each of these individual vehicle 
categories there are particular applications where the use of the 
identified technologies would be either ineffective or not technically 
feasible. For example, the agencies are not predicating the proposed 
standards on the use of full aerodynamic vehicle treatments on 100 
percent of tractors because we know that in many applications (for 
example gravel truck engaged in local aggregate delivery) the added 
weight of the aerodynamic technologies will increase fuel consumption 
and hence CO2 emissions to a greater degree than the 
reduction that would be accomplished from the more aerodynamic nature 
of the tractor.
(i) Aerodynamics Adoption Rate
    The impact of aerodynamics on a tractor-trailer's efficiency 
increases with vehicle speed. Therefore, the usage pattern of the 
vehicle will determine the benefit of various aerodynamic technologies. 
Sleeper cabs are often used in line haul applications and drive the 
majority of their miles on the highway travelling at speeds greater 
than 55 mph. The industry has focused aerodynamic technology 
development, including SmartWay tractors, on these types of trucks. 
Therefore the agencies are proposing the most aggressive aerodynamic 
technology application to this regulatory subcategory. All of the major 
manufacturers today offer at least one SmartWay sleeper cab tractor 
model, which is represented as Bin III aerodynamic performance. The 
proposed aerodynamic adoption rate for Class 8 high roof sleeper cabs 
in 2027 (i.e., the degree of technology adoption on which the 
stringency of the proposed standard is premised) consists of 20 percent 
of Bin IV, 35 percent Bin V, 20 percent Bin VI, and 5 percent Bin VII 
reflecting our assessment of the fraction of tractors in this segment 
that could successfully apply these aerodynamic packages with this 
amount of lead time. We believe that there is sufficient lead time to 
develop aerodynamic tractors that can move the entire high roof sleeper 
cab aerodynamic performance to be as good as or better than today's 
SmartWay designated tractors. The changes required for Bin IV and 
better performance reflect the kinds of improvements projected in the 
Department of Energy's SuperTruck program. That program assumes that 
such systems can be demonstrated on vehicles by 2017. In this case, the 
agencies are projecting that truck manufacturers would be able to begin 
implementing these aerodynamic technologies as early as 2021 MY on a 
limited scale. Importantly, our averaging, banking and trading 
provisions provide manufacturers with the flexibility (and incentive) 
to implement these technologies over time even though the standard 
changes in a single step.
    The aerodynamic adoption rates used to develop the proposed 
standards for the other tractor regulatory categories are less 
aggressive than for the Class 8 sleeper cab high roof. Aerodynamic 
improvements through new tractor designs and the development of new 
aerodynamic components is an inherently slow and iterative process. The 
agencies recognize that there are tractor applications which require 
on/off-road capability and other truck functions which restrict the 
type of aerodynamic equipment applicable. We also recognize that these 
types of trucks spend less time at highway speeds where aerodynamic 
technologies have the greatest benefit. The 2002 VIUS data ranks trucks 
by major use.\162\ The heavy trucks usage indicates that up to 35 
percent of the trucks may be used in on/off-road applications or 
heavier applications. The uses include construction (16 percent), 
agriculture (12 percent), waste management (5 percent), and mining (2 
percent). Therefore, the agencies analyzed the technologies to evaluate 
the potential restrictions that would prevent 100 percent adoption of 
more advanced aerodynamic technologies for all of the tractor 
regulatory subcategories.
---------------------------------------------------------------------------

    \162\ U.S. Department of Energy. Transportation Energy Data 
Book, Edition 28-2009. Table 5.7.
---------------------------------------------------------------------------

    As discussed in Section III.C.2, the agencies propose to increase 
the number of aerodynamic bins for low and mid roof tractors from the 
two levels adopted in Phase 1 to four levels in Phase 2. The agencies 
propose to increase the number of bins for these tractors to reflect 
the actual range of aerodynamic technologies effective in low and mid 
roof tractor applications. The aerodynamic improvements to the bumper, 
hood, windshield, mirrors, and doors are developed for the high roof 
tractor application and then carried over into the low and mid roof 
applications.
(ii) Low Rolling Resistance Tire Adoption Rate
    For the tire manufacturers to further reduce tire rolling 
resistance, the manufacturers must consider several performance 
criteria that affect tire selection. The characteristics of a tire also 
influence durability, traction control, vehicle handling, comfort, and 
retreadability. A single performance parameter can easily be enhanced, 
but an optimal balance of all the criteria will require improvements in 
materials and tread design at a higher cost, as estimated by the 
agencies. Tire design requires balancing performance, since changes in 
design may change different performance characteristics in opposing 
directions. Similar to the discussion regarding lesser aerodynamic 
technology application in tractor segments other than sleeper cab high 
roof, the agencies believe that the proposed standards should not be 
premised on 100 percent application of Level 3 tires in all tractor 
segments given the potential interference with vehicle utility that 
could result.
(iii) Weight Reduction Technology Adoption Rate
    Unlike in HD Phase 1, the agencies propose setting the 2021 through 
2027 model year tractor standards without using weight reduction as a 
technology to demonstrate the feasibility. However, as described in 
Section III.C.2 below, the agencies are proposing an expanded list of 
weight reduction options which could be input into the GEM by the 
manufacturers to reduce their certified CO2 emission and 
fuel consumption levels. The agencies view weight reduction as a 
technology with a high cost that offers a small benefit in the tractor 
sector. For example, our estimate of a 400 pound weight reduction would 
cost $2,050 (2012$) in 2021MY, but offers a 0.3 percent reduction in 
fuel consumption and CO2 emissions.
(iv) Idle Reduction Technology Adoption Rate
    Idle reduction technologies provide significant reductions in fuel 
consumption and CO2 emissions for Class 8 sleeper cabs and 
are available on

[[Page 40224]]

the market today. There are several different technologies available to 
reduce idling. These include APUs, diesel fired heaters, and battery 
powered units. Our discussions with manufacturers indicate that idle 
technologies are sometimes installed in the factory, but it is also a 
common practice to have the units installed after the sale of the 
truck. We would like to continue to incentivize this practice and to do 
so in a manner that the emission reductions associated with idle 
reduction technology occur in use. Therefore, as adopted in Phase 1, we 
are allowing only idle emission reduction technologies which include an 
automatic engine shutoff (AES) with some override provisions.\163\ 
However, we welcome comment on other approaches that would 
appropriately quantify the reductions that would be experienced in the 
real world.
---------------------------------------------------------------------------

    \163\ The agencies are proposing to continue the HD Phase 1 AES 
override provisions included in 40 CFR 1037.660(b) for driver 
safety.
---------------------------------------------------------------------------

    We propose an overall 90 percent adoption rate for this technology 
for Class 8 sleeper cabs. The agencies are unaware of reasons why AES 
with extended idle reduction technologies could not be applied to this 
high fraction of tractors with a sleeper cab, except those deemed a 
vocational tractor, in the available lead time.
    The agencies are interested in extending the idle reduction 
benefits beyond Class 8 sleepers, to day cabs. The agencies reviewed 
literature to quantify the amount of idling which is conducted outside 
of hoteling operations. One study, conducted by Argonne National 
Laboratory, identified several different types of trucks which might 
idle for extended amounts of time during the work day.\164\ Idling may 
occur during the delivery process, queuing at loading docks or border 
crossings, during power take off operations, or to provide comfort 
during the work day. However, the study provided only ``rough 
estimates'' of the idle time and energy use for these vehicles. The 
agencies are not able to appropriately develop a baseline of workday 
idling for day cabs and identify the percent of this idling which could 
be reduced through the use of AES. We welcome comment and data on 
quantifying the effectiveness of AES on day cabs.
---------------------------------------------------------------------------

    \164\ Gaines, L., A. Vyas, J. Anderson. Estimation of Fuel Use 
by Idling Commercial Trucks. January 2006.
---------------------------------------------------------------------------

(v) Vehicle Speed Limiter Adoption Rate
    As adopted in Phase 1, we propose to continue the approach where 
vehicle speed limiters may be used as a technology to meet the proposed 
standard. In setting the proposed standard, however, we assumed a zero 
percent adoption rate of vehicle speed limiters. Although we believe 
vehicle speed limiters are a simple, easy to implement, and inexpensive 
technology, we want to leave the use of vehicles speed limiters to the 
truck purchaser. Since truck fleets purchase tractors today with owner-
set vehicle speed limiters, we considered not including VSLs in our 
compliance model. However, we have concluded that we should allow the 
use of VSLs that cannot be overridden by the operator as a means of 
compliance for vehicle manufacturers that wish to offer it and truck 
purchasers that wish to purchase the technology. In doing so, we are 
providing another means of meeting that standard that can lower 
compliance cost and provide a more optimal vehicle solution for some 
truck fleets or owners. For example, a local beverage distributor may 
operate trucks in a distribution network of primarily local roads. 
Under those conditions, aerodynamic fairings used to reduce aerodynamic 
drag provide little benefit due to the low vehicle speed while adding 
additional mass to the vehicle. A vehicle manufacturer could choose to 
install a VSL set at 55 mph for this vehicle at the request of the 
customer. The resulting tractor would be optimized for its intended 
application and would be fully compliant with our program all at a 
lower cost to the ultimate tractor purchaser.\165\
---------------------------------------------------------------------------

    \165\ Ibid.
    The agencies note that because a VSL value can be input into 
GEM, its benefits can be directly assessed with the model and off 
cycle credit applications therefore are not necessary even though 
the proposed standard is not based on performance of VSLs (i.e. VSL 
is an on-cycle technology).
---------------------------------------------------------------------------

    As in Phase 1, we have chosen not to base the proposed standards on 
performance of VSLs because of concerns about how to set a realistic 
adoption rate that avoids unintended adverse impacts. Although we 
expect there would be some use of VSL, currently it is used when the 
fleet involved decides it is feasible and practicable and increases the 
overall efficiency of the freight system for that fleet operator. To 
date, the compliance data provided by manufacturers indicate that none 
of the tractor configurations include a tamper-proof VSL setting less 
than 65 mph. At this point the agencies are not in a position to 
determine in how many additional situations use of a VSL would result 
in similar benefits to overall efficiency or how many customers would 
be willing to accept a tamper-proof VSL setting. As discussed in 
Section III.E.2.f below, we welcome comment on suggestions to modify 
the tamper-proof requirement while maintaining assurance that the speed 
limiter is used in-use throughout the life of the vehicle. We are not 
able at this time to quantify the potential loss in utility due to the 
use of VSLs, but we welcome comment on whether the use of a VSL would 
require a fleet to deploy additional tractors. Absent this information, 
we cannot make a determination regarding the reasonableness of setting 
a standard based on a particular VSL level. Therefore, the agencies are 
not premising the proposed standards on use of VSL, and instead would 
continue to rely on the industry to select VSL when circumstances are 
appropriate for its use. The agencies have not included either the cost 
or benefit due to VSLs in analysis of the proposed program's costs and 
benefits, therefore it remains a significant flexibility for 
manufacturers to choose.
(vi) Summary of the Adoption Rates Used To Determine the Proposed 
Standards
    Table III-8 through Table III-10 provide the adoption rates of each 
technology broken down by weight class, cab configuration, and roof 
height.

[[Page 40225]]



                    Table III-8--Technology Adoption Rates for Class 7 and 8 Tractors for Determining the Proposed 2021 MY Standards
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Class 7                                           Class 8
                                                      --------------------------------------------------------------------------------------------------
                                                                   Day cab                          Day Cab                        Sleeper Cab
                                                      --------------------------------------------------------------------------------------------------
                                                        Low roof   Mid roof  High roof   Low roof   Mid roof  High roof   Low roof   Mid roof  High roof
                                                           %          %           %         %          %           %         %          %           %
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            2021 MY Engine Technology Package
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             100        100        100        100        100        100        100        100        100
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Aerodynamics
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bin I................................................          0          0          0          0          0          0          0          0          0
Bin II...............................................         75         75          0         75         75          0         75         75          0
Bin III..............................................         25         25         40         25         25         40         25         25         40
Bin IV...............................................          0          0         35          0          0         35          0          0         35
Bin V................................................        N/A        N/A         20        N/A        N/A         20        N/A        N/A         20
Bin VI...............................................        N/A        N/A          5        N/A        N/A          5        N/A        N/A          5
Bin VII..............................................        N/A        N/A          0        N/A        N/A          0        N/A        N/A          0
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Steer Tires
--------------------------------------------------------------------------------------------------------------------------------------------------------
Base.................................................          5          5          5          5          5          5          5          5          5
Level 1..............................................         60         60         60         60         60         60         60         60         60
Level 2..............................................         25         25         25         25         25         25         25         25         25
Level 3..............................................         10         10         10         10         10         10         10         10         10
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Drive Tires
--------------------------------------------------------------------------------------------------------------------------------------------------------
Base.................................................          5          5          5          5          5          5          5          5          5
Level 1..............................................         60         60         60         60         60         60         60         60         60
Level 2..............................................         25         25         25         25         25         25         25         25         25
Level 3..............................................         10         10         10         10         10         10         10         10         10
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Extended Idle Reduction
--------------------------------------------------------------------------------------------------------------------------------------------------------
APU..................................................        N/A        N/A        N/A        N/A        N/A        N/A         80         80         80
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Transmission Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
Manual...............................................         45         45         45         45         45         45         45         45         45
AMT..................................................         40         40         40         40         40         40         40         40         40
Auto.................................................         10         10         10         10         10         10         10         10         10
Dual Clutch..........................................          5          5          5          5          5          5          5          5          5
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Driveline
--------------------------------------------------------------------------------------------------------------------------------------------------------
Axle Lubricant.......................................         20         20         20         20         20         20         20         20         20
6x2 or 4x2 Axle......................................  .........  .........  .........         10         10         20         10         10         20
Downspeed............................................         20         20         20         20         20         20         20         20         20
                                                                 Accessory Improvements
--------------------------------------------------------------------------------------------------------------------------------------------------------
A/C..................................................         10         10         10         10         10         10         10         10         10
Electric Access......................................         10         10         10         10         10         10         10         10         10
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Other Technologies
--------------------------------------------------------------------------------------------------------------------------------------------------------
Predictive Cruise Control............................         20         20         20         20         20         20         20         20         20
Automated Tire Inflation System......................         20         20         20         20         20         20         20         20         20
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 40226]]


                    Table III-9--Technology Adoption Rates for Class 7 and 8 Tractors for Determining the Proposed 2024 MY Standards
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Class 7                                           Class 8
                                                      --------------------------------------------------------------------------------------------------
                                                                   Day cab                          Day cab                        Sleeper cab
                                                      --------------------------------------------------------------------------------------------------
                                                        Low roof   Mid roof  High roof   Low roof   Mid roof  High roof   Low roof   Mid roof  High roof
                                                           %          %           %         %          %           %         %          %           %
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            2024 MY Engine Technology Package
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             100        100        100        100        100        100        100        100        100
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Aerodynamics
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bin I................................................          0          0          0          0          0          0          0          0          0
Bin II...............................................         60         60          0         60         60          0         60         60          0
Bin III..............................................         38         38         30         38         38         30         38         38         30
Bin IV...............................................          2          2         30          2          2         30          2          2         30
Bin V................................................        N/A        N/A         25        N/A        N/A         25        N/A        N/A         25
Bin VI...............................................        N/A        N/A         13        N/A        N/A         13        N/A        N/A         13
Bin VII..............................................        N/A        N/A          2        N/A        N/A          2        N/A        N/A          2
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Steer Tires
--------------------------------------------------------------------------------------------------------------------------------------------------------
Base.................................................          5          5          5          5          5          5          5          5          5
Level 1..............................................         50         50         50         50         50         50         50         50         50
Level 2..............................................         30         30         30         30         30         30         30         30         30
Level 3..............................................         15         15         15         15         15         15         15         15         15
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Drive Tires
--------------------------------------------------------------------------------------------------------------------------------------------------------
Base.................................................          5          5          5          5          5          5          5          5          5
Level 1..............................................         50         50         50         50         50         50         50         50         50
Level 2..............................................         30         30         30         30         30         30         30         30         30
Level 3..............................................         15         15         15         15         15         15         15         15         15
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Extended Idle Reduction
--------------------------------------------------------------------------------------------------------------------------------------------------------
APU..................................................        N/A        N/A        N/A        N/A        N/A        N/A         90         90         90
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Transmission Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
Manual...............................................         20         20         20         20         20         20         20         20         20
AMT..................................................         50         50         50         50         50         50         50         50         50
Auto.................................................         20         20         20         20         20         20         20         20         20
Dual Clutch..........................................         10         10         10         10         10         10         10         10         10
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Driveline
--------------------------------------------------------------------------------------------------------------------------------------------------------
Axle Lubricant.......................................         40         40         40         40         40         40         40         40         40
6x2 or 4x2 Axle......................................  .........  .........  .........         20         20         60         20         20         60
Downspeed............................................         40         40         40         40         40         40         40         40         40
Direct Drive.........................................         50         50         50         50         50         50         50         50         50
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Accessory Improvements
--------------------------------------------------------------------------------------------------------------------------------------------------------
A/C..................................................         20         20         20         20         20         20         20         20         20
Electric Access......................................         20         20         20         20         20         20         20         20         20
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Other Technologies
--------------------------------------------------------------------------------------------------------------------------------------------------------
Predictive Cruise Control............................         40         40         40         40         40         40         40         40         40
Automated Tire Inflation System......................         40         40         40         40         40         40         40         40         40
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 40227]]


                    Table III-10--Technology Adoption Rates for Class 7 and 8 Tractors for Determining the Proposed 2027 MY Standards
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Class 7                                           Class 8
                                                      --------------------------------------------------------------------------------------------------
                                                                   Day cab                          Day cab                        Sleeper cab
                                                      --------------------------------------------------------------------------------------------------
                                                        Low roof   Mid roof  High roof   Low roof   Mid roof  High roof   Low roof   Mid roof  High roof
                                                           %          %           %         %          %           %         %          %           %
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            2027 MY Engine Technology Package
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             100        100        100        100        100        100        100        100        100
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Aerodynamics
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bin I................................................          0          0          0          0          0          0          0          0          0
Bin II...............................................         50         50          0         50         50          0         50         50          0
Bin III..............................................         40         40         20         40         40         20         40         40         20
Bin IV...............................................         10         10         20         10         10         20         10         10         20
Bin V................................................        N/A        N/A         35        N/A        N/A         35        N/A        N/A         35
Bin VI...............................................        N/A        N/A         20        N/A        N/A         20        N/A        N/A         20
Bin VII..............................................        N/A        N/A          5        N/A        N/A          5        N/A        N/A          5
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Steer Tires
--------------------------------------------------------------------------------------------------------------------------------------------------------
Base.................................................          5          5          5          5          5          5          5          5          5
Level 1..............................................         20         20         20         20         20         20         20         20         20
Level 2..............................................         50         50         50         50         50         50         50         50         50
Level 3..............................................         25         25         25         25         25         25         25         25         25
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Drive Tires
--------------------------------------------------------------------------------------------------------------------------------------------------------
Base.................................................          5          5          5          5          5          5          5          5          5
Level 1..............................................         20         20         20         20         20         20         20         20         20
Level 2..............................................         50         50         50         50         50         50         50         50         50
Level 3..............................................         25         25         25         25         25         25         25         25         25
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Extended Idle Reduction
--------------------------------------------------------------------------------------------------------------------------------------------------------
APU..................................................        N/A        N/A        N/A        N/A        N/A        N/A         90         90         90
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Transmission Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
Manual...............................................         10         10         10         10         10         10         10         10         10
AMT..................................................         50         50         50         50         50         50         50         50         50
Auto.................................................         30         30         30         30         30         30         30         30         30
Dual Clutch..........................................         10         10         10         10         10         10         10         10         10
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Driveline
--------------------------------------------------------------------------------------------------------------------------------------------------------
Axle Lubricant.......................................         40         40         40         40         40         40         40         40         40
6x2 Axle.............................................  .........  .........  .........         20         20         60         20         20         60
Downspeed............................................         60         60         60         60         60         60         60         60         60
Direct Drive.........................................         50         50         50         50         50         50         50         50         50
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Accessory Improvements
--------------------------------------------------------------------------------------------------------------------------------------------------------
A/C..................................................         30         30         30         30         30         30         30         30         30
Electric Access......................................         30         30         30         30         30         30         30         30         30
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Other Technologies
--------------------------------------------------------------------------------------------------------------------------------------------------------
Predictive Cruise Control............................         40         40         40         40         40         40         40         40         40
Automated Tire Inflation System......................         40         40         40         40         40         40         40         40         40
--------------------------------------------------------------------------------------------------------------------------------------------------------

(d) Derivation of the Proposed Tractor Standards
    The agencies used the technology effectiveness inputs and 
technology adoption rates to develop GEM inputs to derive the proposed 
HD Phase 2 fuel consumption and CO2 emissions standards for 
each subcategory of Class 7 and 8 combination tractors. Note that we 
have analyzed one technology pathway for each proposed level of 
stringency, but manufacturers would be free to use any combination of 
technology to meet the standards, and with the flexibility of 
averaging, banking and trading, to meet the standard on average. The 
agencies derived a scenario tractor for each subcategory by weighting 
the individual GEM input parameters included in Table III-7 with the 
adoption rates in Table III-8 through Table III-10. For example, the 
proposed CdA value for a 2021MY Class 8 Sleeper Cab High Roof scenario 
case was

[[Page 40228]]

derived as 40 percent times 6.3 plus 35 percent times 5.6 plus 20 
percent times 5.1 plus 5 percent times 4.7, which is equal to a CdA of 
5.74 m\2\. Similar calculations were made for tire rolling resistance, 
transmission types, idle reduction, and other technologies. To account 
for the proposed engine standards and engine technologies, the agencies 
assumed a compliant engine fuel map in GEM.\166\ The agencies then ran 
GEM with a single set of vehicle inputs, as shown in Table III-11, to 
derive the proposed standards for each subcategory. Additional detail 
is provided in the draft RIA Chapter 2.
---------------------------------------------------------------------------

    \166\ See Section II.D above explaining the derivation of the 
proposed engine standards.

             Table III-11--GEM Inputs for the Proposed 2021MY Class 7 and 8 Tractor Standard Setting
----------------------------------------------------------------------------------------------------------------
               Class 7                                                  Class 8
----------------------------------------------------------------------------------------------------------------
               Day cab                                Day cab                             Sleeper cab
----------------------------------------------------------------------------------------------------------------
  Low roof     Mid roof    High roof     Low roof     Mid roof    High roof    Low roof    Mid roof    High roof
----------------------------------------------------------------------------------------------------------------
                                                     Engine
----------------------------------------------------------------------------------------------------------------
2021MY 11L   2021MY 11L   2021MY 11L   2021MY 15L   2021MY 15L   2021MY 15L   2021MY 15L  2021MY 15L  2021MY 15L
 Engine 350  Engine 350   Engine 350   Engine 455   Engine 455   Engine 455   Engine 455  Engine 455  Engine 455
         HP          HP           HP           HP           HP           HP          HP          HP          HP
----------------------------------------------------------------------------------------------------------------
                                           Aerodynamics (CdA in m\2\)
----------------------------------------------------------------------------------------------------------------
      4.68         6.08         5.94         4.68         6.08         5.94        4.68        6.08        5.74
----------------------------------------------------------------------------------------------------------------
                                       Steer Tires (CRR in kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       6.2          6.2          6.2          6.2          6.2          6.2         6.2         6.2         6.2
----------------------------------------------------------------------------------------------------------------
                                       Drive Tires (CRR in kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       6.6          6.6          6.6          6.6          6.6          6.6         6.6         6.6         6.6
----------------------------------------------------------------------------------------------------------------
                                 Extended Idle Reduction Weighted Effectiveness
----------------------------------------------------------------------------------------------------------------
       N/A          N/A          N/A          N/A          N/A          N/A        2.5%        2.5%        2.5%
----------------------------------------------------------------------------------------------------------------
                              Transmission = 10 speed Automated Manual Transmission
----------------------------------------------------------------------------------------------------------------
                    Gear Ratios = 12.8, 9.25, 6.76, 4.90, 3.58, 2.61, 1.89, 1.38, 1.00, 0.73
----------------------------------------------------------------------------------------------------------------
                                             Drive axle Ratio = 3.55
----------------------------------------------------------------------------------------------------------------
                                         6x2 Axle Weighted Effectiveness
----------------------------------------------------------------------------------------------------------------
       N/A          N/A          N/A         0.3%         0.3%         0.5%        0.3%        0.3%        0.5%
----------------------------------------------------------------------------------------------------------------
                        Low Friction Axle Lubrication = 0.1%
----------------------------------------------------------------------------------------------------------------
                                           Transmission benefit = 1.1%
----------------------------------------------------------------------------------------------------------------
                                        Predictive Cruise Control = 0.4%
----------------------------------------------------------------------------------------------------------------
                                          Accessory Improvements = 0.1%
----------------------------------------------------------------------------------------------------------------
                                 Air Conditioner Efficiency Improvements = 0.1%
----------------------------------------------------------------------------------------------------------------
                                     Automatic Tire Inflation Systems = 0.2%
----------------------------------------------------------------------------------------------------------------
                                            Weight Reduction = 0 lbs
----------------------------------------------------------------------------------------------------------------


[[Page 40229]]


             Table III-12--GEM Inputs for the Proposed 2024MY Class 7 and 8 Tractor Standard Setting
----------------------------------------------------------------------------------------------------------------
               Class 7                                                  Class 8
----------------------------------------------------------------------------------------------------------------
               Day cab                                Day cab                             Sleeper cab
----------------------------------------------------------------------------------------------------------------
  Low roof     Mid roof    High roof     Low roof     Mid roof    High roof    Low roof    Mid roof    High roof
----------------------------------------------------------------------------------------------------------------
                                                     Engine
----------------------------------------------------------------------------------------------------------------
2024MY 11L   2024MY 11L   2024MY 11L   2024MY 15L   2024MY 15L   2024MY 15L   2024MY 15L  2024MY 15L  2024MY 15L
 Engine 350  Engine 350   Engine 350   Engine 455   Engine 455   Engine 455   Engine 455  Engine 455  Engine 455
         HP          HP           HP           HP           HP           HP          HP          HP          HP
----------------------------------------------------------------------------------------------------------------
                                           Aerodynamics (CdA in m\2\)
----------------------------------------------------------------------------------------------------------------
      4.59         5.99         5.74         4.59         5.99         5.74        4.59        5.99        5.54
----------------------------------------------------------------------------------------------------------------
                                       Steer Tires (CRR in kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       5.9          5.9          5.9          5.9          5.9          5.9         5.9         5.9         5.9
                                       Drive Tires (CRR in kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       6.2          6.2          6.2          6.2          6.2          6.2         6.2         6.2         6.2
----------------------------------------------------------------------------------------------------------------
                                 Extended Idle Reduction Weighted Effectiveness
----------------------------------------------------------------------------------------------------------------
       N/A          N/A          N/A          N/A          N/A          N/A          3%          3%          3%
----------------------------------------------------------------------------------------------------------------
                              Transmission = 10 speed Automated Manual Transmission
----------------------------------------------------------------------------------------------------------------
                    Gear Ratios = 12.8, 9.25, 6.76, 4.90, 3.58, 2.61, 1.89, 1.38, 1.00, 0.73
----------------------------------------------------------------------------------------------------------------
                                             Drive axle Ratio = 3.36
----------------------------------------------------------------------------------------------------------------
                                         6x2 Axle Weighted Effectiveness
----------------------------------------------------------------------------------------------------------------
       N/A          N/A          N/A         0.5%         0.5%         1.5%        0.5%        0.5%        1.5%
----------------------------------------------------------------------------------------------------------------
                                      Low Friction Axle Lubrication = 0.2%
----------------------------------------------------------------------------------------------------------------
                                           Transmission benefit = 1.6%
----------------------------------------------------------------------------------------------------------------
                                        Predictive Cruise Control = 0.8%
----------------------------------------------------------------------------------------------------------------
                                          Accessory Improvements = 0.2%
----------------------------------------------------------------------------------------------------------------
                                 Air Conditioner Efficiency Improvements = 0.1%
----------------------------------------------------------------------------------------------------------------
                                     Automatic Tire Inflation Systems = 0.4%
----------------------------------------------------------------------------------------------------------------
                                            Weight Reduction = 0 lbs
----------------------------------------------------------------------------------------------------------------
                    Direct Drive Weighted Efficiency = 1% for sleeper cabs; 0.8% for day cabs
----------------------------------------------------------------------------------------------------------------


             Table III-13--GEM Inputs for the Proposed 2027MY Class 7 and 8 Tractor Standard Setting
----------------------------------------------------------------------------------------------------------------
               Class 7                                                  Class 8
----------------------------------------------------------------------------------------------------------------
               Day cab                                Day cab                             Sleeper cab
----------------------------------------------------------------------------------------------------------------
  Low roof     Mid roof    High roof     Low roof     Mid roof    High roof    Low roof    Mid roof    High roof
----------------------------------------------------------------------------------------------------------------
                                                     Engine
----------------------------------------------------------------------------------------------------------------
2027MY 11L   2027MY 11L   2027MY 11L   2027MY 15L   2027MY 15L   2027MY 15L   2027MY 15L  2027MY 15L  2027MY 15L
 Engine 350  Engine 350   Engine 350   Engine 455   Engine 455   Engine 455   Engine 455  Engine 455  Engine 455
         HP          HP           HP           HP           HP           HP          HP          HP          HP
----------------------------------------------------------------------------------------------------------------
                                           Aerodynamics (CdA in m\2\)
----------------------------------------------------------------------------------------------------------------
      4.52         5.92         5.52         4.52         5.92         5.52        4.52        5.92        5.32
----------------------------------------------------------------------------------------------------------------
                                       Steer Tires (CRR in kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       5.6          5.6          5.6          5.6          5.6          5.6         5.6         5.6         5.6
----------------------------------------------------------------------------------------------------------------

[[Page 40230]]

 
                                       Drive Tires (CRR in kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       5.9          5.9          5.9          5.9          5.9          5.9         5.9         5.9         5.9
----------------------------------------------------------------------------------------------------------------
                                 Extended Idle Reduction Weighted Effectiveness
----------------------------------------------------------------------------------------------------------------
       N/A          N/A          N/A          N/A          N/A          N/A          3%          3%          3%
----------------------------------------------------------------------------------------------------------------
                              Transmission = 10 speed Automated Manual Transmission
----------------------------------------------------------------------------------------------------------------
                    Gear Ratios = 12.8, 9.25, 6.76, 4.90, 3.58, 2.61, 1.89, 1.38, 1.00, 0.73
----------------------------------------------------------------------------------------------------------------
                                             Drive axle Ratio = 3.2
----------------------------------------------------------------------------------------------------------------
                                         6x2 Axle Weighted Effectiveness
----------------------------------------------------------------------------------------------------------------
       N/A          N/A          N/A         0.5%         0.5%         1.5%        0.5%        0.5%        1.5%
----------------------------------------------------------------------------------------------------------------
                                      Low Friction Axle Lubrication = 0.2%
----------------------------------------------------------------------------------------------------------------
                                           Transmission benefit = 1.8%
----------------------------------------------------------------------------------------------------------------
                                        Predictive Cruise Control = 0.8%
----------------------------------------------------------------------------------------------------------------
                                          Accessory Improvements = 0.3%
----------------------------------------------------------------------------------------------------------------
                                 Air Conditioner Efficiency Improvements = 0.2%
----------------------------------------------------------------------------------------------------------------
                                     Automatic Tire Inflation Systems = 0.4%
----------------------------------------------------------------------------------------------------------------
                                            Weight Reduction = 0 lbs
----------------------------------------------------------------------------------------------------------------
                    Direct Drive Weighted Efficiency = 1% for sleeper cabs; 0.8% for day cabs
----------------------------------------------------------------------------------------------------------------

    The proposed level of the 2027 model year standards, in addition to 
the phase-in standards in model years 2021 and 2024 for each 
subcategory is included in Table III-14.

                    Table III-14--Proposed 2021, 2024, and 2027 Model Year Tractor Standards
----------------------------------------------------------------------------------------------------------------
                                                                              Day cab               Sleeper Cab
                                                                 -----------------------------------------------
                                                                      Class 7         Class 8         Class 8
----------------------------------------------------------------------------------------------------------------
                                     2021 Model Year CO2 Grams per Ton-Mile
----------------------------------------------------------------------------------------------------------------
Low Roof........................................................              97              78              70
Mid Roof........................................................             107              84              78
High Roof.......................................................             109              86              77
----------------------------------------------------------------------------------------------------------------
                               2021 Model Year Gallons of Fuel per 1,000 Ton-Mile
----------------------------------------------------------------------------------------------------------------
Low Roof........................................................          9.5285          7.6621          6.8762
Mid Roof........................................................         10.5108          8.2515          7.6621
High Roof.......................................................         10.7073          8.4479          7.5639
----------------------------------------------------------------------------------------------------------------
                                     2024 Model Year CO2 Grams per Ton-Mile
----------------------------------------------------------------------------------------------------------------
Low Roof........................................................              90              72              64
Mid Roof........................................................             100              78              71
High Roof.......................................................             101              79              70
----------------------------------------------------------------------------------------------------------------
                          2024 Model Year and Later Gallons of Fuel per 1,000 Ton-Mile
----------------------------------------------------------------------------------------------------------------
Low Roof........................................................          8.8409          7.0727          6.2868
Mid Roof........................................................          9.8232          7.6621          6.9745
High Roof.......................................................          9.9214          7.7603          6.8762
----------------------------------------------------------------------------------------------------------------

[[Page 40231]]

 
                                     2027 Model Year CO2 Grams per Ton-Mile
----------------------------------------------------------------------------------------------------------------
Low Roof........................................................              87              70              62
Mid Roof........................................................              96              76              69
High Roof.......................................................              96              76              67
----------------------------------------------------------------------------------------------------------------
                          2027 Model Year and Later Gallons of Fuel per 1,000 Ton-Mile
----------------------------------------------------------------------------------------------------------------
Low Roof........................................................          8.5462          6.8762          6.0904
Mid Roof........................................................          9.4303          7.4656          6.7780
High Roof.......................................................          9.4303          7.4656          6.5815
----------------------------------------------------------------------------------------------------------------

    A summary of the draft technology package costs is included in 
Table III-15 through Table III-17 for MYs 2021, 2024, and 2027, 
respectively, with additional details available in the draft RIA 
Chapter 2.12. We welcome comments on the technology costs.

    Table III-15--Class 7 and 8 Tractor Technology Incremental Costs in the 2021 Model Year \a\ \b\ Preferred
                                    Alternative vs. the Less Dynamic Baseline
                                               [2012$ per vehicle]
----------------------------------------------------------------------------------------------------------------
                                            Class 7                               Class 8
                                    ----------------------------------------------------------------------------
                                            Day cab               Day cab                  Sleeper cab
                                    ----------------------------------------------------------------------------
                                      Low/mid               Low/mid
                                        roof    High roof     roof    High roof   Low roof   Mid roof  High roof
----------------------------------------------------------------------------------------------------------------
Engine \c\.........................       $314       $314       $314       $314       $314       $314       $314
Aerodynamics.......................        687        511        687        511        656        656        535
Tires..............................         49          9         81         15         59         59         15
Tire inflation system..............        180        180        180        180        180        180        180
Transmission.......................      3,969      3,969      3,969      3,969      3,969      3,969      3,969
Axle & axle lubes..................         50         50         70         90         70         70         90
Idle reduction with APU............          0          0          0          0      2,449      2,449      2,449
Air conditioning...................         45         45         45         45         45         45         45
Other vehicle technologies.........        174        174        174        174        174        174        174
                                    ----------------------------------------------------------------------------
    Total..........................      5,468      5,252      5,520      5,298      7,916      7,916      7,771
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ Costs shown are for the 2021 model year and are incremental to the costs of a tractor meeting the Phase 1
  standards. These costs include indirect costs via markups along with learning impacts. For a description of
  the markups and learning impacts considered in this analysis and how it impacts technology costs for other
  years, refer to Chapter 2 of the draft RIA (see draft RIA 2.12).
\b\ Note that values in this table include adoption rates. Therefore, the technology costs shown reflect the
  average cost expected for each of the indicated tractor classes. To see the actual estimated technology costs
  exclusive of adoption rates, refer to Chapter 2 of the draft RIA (see draft RIA 2.12 in particular).
\c\ Engine costs are for a heavy HD diesel engine meant for a combination tractor. The engine costs in this
  table are equal to the engine costs associated with the separate engine standard because both include the same
  set of engine technologies (see Section II.D.2.d.i).


    Table III-16--Class 7 and 8 Tractor Technology Incremental Costs in the 2024 Model Year \a\ \b\ Preferred
                                    Alternative vs. the Less Dynamic Baseline
                                               [2012$ per vehicle]
----------------------------------------------------------------------------------------------------------------
                                            Class 7                               Class 8
                                    ----------------------------------------------------------------------------
                                            Day cab               Day cab                  Sleeper cab
                                    ----------------------------------------------------------------------------
                                      Low/mid               Low/mid
                                        roof    High roof     roof    High roof   Low roof   Mid roof  High roof
----------------------------------------------------------------------------------------------------------------
Engine \c\.........................       $904       $904       $904       $904       $904       $904       $904
Aerodynamics.......................        744        684        744        684        712        712        723
Tires..............................         47         11         78         18         58         58         18
Tire inflation system..............        330        330        330        330        330        330        330
Transmission.......................      5,883      5,883      5,883      5,883      5,883      5,883      5,883
Axle & axle lubes..................         92         92        128        200        128        128        200
Idle reduction with APU............          0          0          0          0      2,687      2,687      2,687
Air conditioning...................         82         82         82         82         82         82         82

[[Page 40232]]

 
Other vehicle technologies.........        318        318        318        318        318        318        318
                                    ----------------------------------------------------------------------------
    Total..........................      8,400      8,304      8,467      8,419     11,102     11,102     11,145
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ Costs shown are for the 2024 model year and are incremental to the costs of a tractor meeting the Phase 1
  standards. These costs include indirect costs via markups along with learning impacts. For a description of
  the markups and learning impacts considered in this analysis and how it impacts technology costs for other
  years, refer to Chapter 2 of the draft RIA (see draft RIA 2.12).
\b\ Note that values in this table include adoption rates. Therefore, the technology costs shown reflect the
  average cost expected for each of the indicated tractor classes. To see the actual estimated technology costs
  exclusive of adoption rates, refer to Chapter 2 of the draft RIA (see draft RIA 2.12).
\c\ Engine costs are for a heavy HD diesel engine meant for a combination tractor. The engine costs in this
  table are equal to the engine costs associated with the separate engine standard because both include the same
  set of engine technologies (see Section II.D.2.d.i).


    Table III-17--Class 7 and 8 Tractor Technology Incremental Costs in the 2027 Model Year \a\ \b\ Preferred
                                    Alternative vs. the Less Dynamic Baseline
                                               [2012$ per vehicle]
----------------------------------------------------------------------------------------------------------------
                                            Class 7                               Class 8
                                    ----------------------------------------------------------------------------
                                            Day cab               Day cab                  Sleeper cab
                                    ----------------------------------------------------------------------------
                                      Low/mid               Low/mid
                                        roof    High roof     roof    High roof   Low roof   Mid roof  High roof
----------------------------------------------------------------------------------------------------------------
Engine \c\.........................     $1,698     $1,698     $1,698     $1,698     $1,698     $1,698     $1,698
Aerodynamics.......................        771        765        771        765        733        733        802
Tires..............................         45         10         75         17         56         56         17
Tire inflation system..............        314        314        314        314        314        314        314
Transmission.......................      6,797      6,797      6,797      6,797      6,797      6,797      6,797
Axle & axle lubes..................         97         97        131        200        131        131        200
Idle reduction with APU............          0          0          0          0      2,596      2,596      2,596
Air conditioning...................        117        117        117        117        117        117        117
Other vehicle technologies.........        302        302        302        302        302        302        302
                                    ----------------------------------------------------------------------------
    Total..........................     10,140     10,099     10,204     10,209     12,744     12,744     12,842
----------------------------------------------------------------------------------------------------------------
Notes:
\a\ Costs shown are for the 2027 model year and are incremental to the costs of a tractor meeting the Phase 1
  standards. These costs include indirect costs via markups along with learning impacts. For a description of
  the markups and learning impacts considered in this analysis and how it impacts technology costs for other
  years, refer to Chapter 2 of the draft RIA (see draft RIA 2.12).
\b\ Note that values in this table include adoption rates. Therefore, the technology costs shown reflect the
  average cost expected for each of the indicated tractor classes. To see the actual estimated technology costs
  exclusive of adoption rates, refer to Chapter 2 of the draft RIA (see draft RIA 2.12 in particular).
\c\ Engine costs are for a heavy HD diesel engine meant for a combination tractor. The engine costs in this
  table are equal to the engine costs associated with the separate engine standard because both include the same
  set of engine technologies (see Section II.D.2.d.i).

(i) Proposed Heavy-Haul Tractor Standards
    For Phase 2, the agencies propose to add a tenth subcategory to the 
tractor category for heavy-haul tractors. The agencies recognize the 
need for manufacturers to build these types of vehicles for specific 
applications and believe the appropriate way to prevent penalizing 
these vehicles is to set separate standards recognizing a heavy-haul 
vehicle's unique needs, such as requiring a higher horsepower engine or 
different transmissions. The agencies are proposing this change in 
Phase 2 because unlike in Phase 1 the engine, transmission, and 
drivetrain technologies are included in the technology packages used to 
determine the stringency of the proposed tractor standards and are 
included as manufacturer inputs in GEM. This means that the agencies 
can adopt a standard reflecting individualized performance of these 
technologies in particular applications, in this case, heavy-haul 
tractors, and further, have a means of reliably assessing 
individualized performance of these technology at certification.
    The typical tractor is designed with a Gross Combined Weight Rating 
(GCWR) of approximately 80,000 lbs due to the effective weight limit on 
the federal highway system, except in states with preexisting higher 
weight limits. The agencies propose to consider tractors with a GCWR 
over 120,000 lbs as heavy-haul tractors. Based on comments received 
during the development of HD Phase 1 (76 FR 57136-57138) and because we 
are not proposing a sales limit for heavy-haul like we have for the 
vocational tractors, the agencies also believe it would be appropriate 
to further define the heavy-haul vehicle characteristics to 
differentiate these vehicles from the vehicles in the other nine 
tractor subcategories. The two additional requirements would include

[[Page 40233]]

a total gear reduction greater than or equal to 57:1 and a frame 
Resisting Bending Moment (RBM) greater than or equal to 2,000,000 in-
lbs per rail or rail and liner combination. Heavy-haul tractors 
typically require the large gear reduction to provide the torque 
necessary to start the vehicle moving. These vehicles also typically 
require frame rails with extra strength to ensure the ability to haul 
heavy loads. We welcome comment on the proposed heavy-haul tractor 
specifications, including whether Gross Vehicle Weight Rating (GVWR) or 
Gross Axle Weight Rating (GAWR) would be a more appropriate metric to 
differentiate between a heavy-haul tractor and a typical tractor.
    The agencies propose that heavy-haul tractors demonstrate 
compliance with the proposed standards using the day cab drive cycle 
weightings of 19 percent transient cycle, 17 percent 55 mph cycle, and 
64 percent 65 mph cycle. We also propose that GEM simulates the heavy-
haul tractors with a payload of 43 tons and a total tractor, trailer, 
and payload weight of 118,500 lbs. In addition, we propose that the 
engines installed in heavy-haul tractors meet the proposed tractor 
engine standards included in 40 CFR 1036.108. We welcome comments on 
these proposed specifications.
    The agencies recognize that certain technologies used to determine 
the stringency of the proposed Phase 2 tractor standards are less 
applicable to heavy-haul tractors. Heavy-haul tractors are not 
typically used in the same manner as long-haul tractors with extended 
highway driving, and therefore would experience less benefit from 
aerodynamics. Aerodynamic technologies are very effective at reducing 
the fuel consumption and GHG emissions of tractors, but only when 
traveling at highway speeds. At lower speeds, the aerodynamic 
technologies may have a detrimental impact due to the potential of 
added weight. The agencies therefore are not considering the use of 
aerodynamic technologies in the development of the proposed Phase 2 
heavy-haul tractor standards. Moreover, because aerodynamics would not 
play a role in the heavy-haul standards, the agencies propose to 
combine all of the heavy-haul tractor cab configurations (day and 
sleeper) and roof heights (low, mid, and high) into a single heavy-haul 
tractor subcategory.\167\ We welcome comment on this approach.
---------------------------------------------------------------------------

    \167\ Since aerodynamic improvements are not part of the 
technology package, the agencies likewise are not proposing any bin 
structure for the heavy-haul tractor subcategory.
---------------------------------------------------------------------------

    Certain powertrain and drivetrain components are also impacted 
during the design of a heavy-haul tractor, including the transmission, 
axles, and the engine. Heavy-haul tractors typically require 
transmissions with 13 or 18 speeds to provide the ratio spread to 
ensure that the tractor is able to start pulling the load from a stop. 
Downsped powertrains are typically not an option for heavy-haul 
operations because these vehicles require more torque to move the 
vehicle because of the heavier load. Finally, due to the loading 
requirements of the vehicle, it is not likely that a 6x2 axle 
configuration can be used in heavy-haul applications.
    The agencies used the following heavy-haul tractor inputs for 
developing the proposed 2021, 2024, and 2027 MY standards, as shown in 
Table III-18 and Table III-19.

     Table III-18--Application Rates for Proposed Heavy-Haul Tractor
                                Standards
------------------------------------------------------------------------
                  Heavy-Haul Tractor Application Rates
-------------------------------------------------------------------------
                                      2021MY       2024MY       2027MY
                                  --------------------------------------
              Engine               2021 MY 15L  2024 MY 15L  2027 MY 15L
                                   Engine with  Engine with  Engine with
                                    600 HP (%)   600 HP (%)   600 HP (%)
------------------------------------------------------------------------
                            Aerodynamics--0%
------------------------------------------------------------------------
                               Steer Tires
------------------------------------------------------------------------
Phase 1 Baseline.................            5            5            5
Level I..........................           60           50           20
Level 2..........................           25           30           50
Level 3..........................           10           15           25
------------------------------------------------------------------------
                               Drive Tires
------------------------------------------------------------------------
Phase 1 Baseline.................            5            5            5
Level I..........................           60           50           20
Level 2..........................           25           30           50
Level 3..........................           10           15           25
------------------------------------------------------------------------
                              Transmission
------------------------------------------------------------------------
AMT..............................           40           50           50
Automatic........................           10           20           30
DCT..............................            5           10           10
------------------------------------------------------------------------
                           Other Technologies
------------------------------------------------------------------------
6x2 Axle.........................            0            0            0
Low Friction Axle Lubrication....           20           40           40
Predictive Cruise Control........           20           40           40
Accessory Improvements...........           10           20           30
Air Conditioner Efficiency                  10           20           30
 Improvements....................
Automatic Tire Inflation Systems.           20           40           40

[[Page 40234]]

 
Weight Reduction.................            0            0            0
------------------------------------------------------------------------


            Table III-19--GEM Inputs for Proposed 2021, 2024 and 2027 MY Heavy-Haul Tractor Standards
----------------------------------------------------------------------------------------------------------------
                                               Heavy-haul tractor
-----------------------------------------------------------------------------------------------------------------
               Baseline                         2021MY                   2024MY                   2027MY
----------------------------------------------------------------------------------------------------------------
Engine = 2017 MY 15L Engine with 600   Engine = 2021 MY 15L     Engine = 2024 MY 15L     Engine = 2027 MY 15L
 HP.                                    Engine with 600 HP.      Engine with 600 HP.      Engine with 600 HP
----------------------------------------------------------------------------------------------------------------
                                        Aerodynamics (CdA in m\2\) = 5.00
----------------------------------------------------------------------------------------------------------------
Steer Tires (CRR in kg/metric ton) =   Steer Tires (CRR in kg/  Steer Tires (CRR in kg/  Steer Tires (CRR in kg/
 7.0.                                   metric ton) = 6.2.       metric ton) = 6.0.       metric ton) = 5.8.
Drive Tires (CRR in kg/metric ton) =   Drive Tires (CRR in kg/  Drive Tires (CRR in kg/  Drive Tires (CRR in kg/
 7.4.                                   metric ton) = 6.6.       metric ton) = 6.4.       metric ton) = 6.2.
Transmission = 13 speed Manual         Transmission = 13 speed  Transmission = 13 speed  Transmission = 13 speed
 Transmission, Gear Ratios = 12.29,     Automated Manual         Automated Manual         Automated Manual
 8.51, 6.05, 4.38, 3.20, 2.29, 1.95,    Transmission, Gear       Transmission, Gear       Transmission, Gear
 1.62, 1.38, 1.17, 1.00, 0.86, 0.73.    Ratios = 12.29, 8.51,    Ratios = 12.29, 8.51,    Ratios = 12.29, 8.51,
                                        6.05, 4.38, 3.20,        6.05, 4.38, 3.20,        6.05, 4.38, 3.20,
                                        2.29, 1.95, 1.62,        2.29, 1.95, 1.62,        2.29, 1.95, 1.62,
                                        1.38, 1.17, 1.00,        1.38, 1.17, 1.00,        1.38, 1.17, 1.00,
                                        0.86, 0.73.              0.86, 0.73.              0.86, 0.73.
Drive axle Ratio = 3.55..............  Drive axle Ratio = 3.55  Drive axle Ratio = 3.55  Drive axle Ratio =
                                                                                          3.55.
N/A..................................  6x2 Axle Weighted        6x2 Axle Weighted        6x2 Axle Weighted
                                        Effectiveness = 0%.      Effectiveness = 0%.      Effectiveness = 0%.
N/A..................................  Low Friction Axle        Low Friction Axle        Low Friction Axle
                                        Lubrication = 0.1%.      Lubrication = 0.2%.      Lubrication = 0.2%.
N/A..................................  AMT benefit = 1.1%.....  AMT benefit = 1.8%.....  AMT benefit = 1.8%.
N/A..................................  Predictive Cruise        Predictive Cruise        Predictive Cruise
                                        Control = 0.4%.          Control = 0.8%.          Control = 0.8%.
N/A..................................  Accessory Improvements   Accessory Improvements   Accessory Improvements
                                        = 0.1%.                  = 0.2%.                  = 0.3%.
N/A..................................  Air Conditioner          Air Conditioner          Air Conditioner
                                        Efficiency               Efficiency               Efficiency
                                        Improvements = 0.1%.     Improvements = 0.1%.     Improvements = 0.2%.
N/A..................................  Automatic Tire           Automatic Tire           Automatic Tire
                                        Inflation Systems =      Inflation Systems =      Inflation Systems =
                                        0.2%.                    0.4%.                    0.4%.
N/A..................................  Weight Reduction = 0     Weight Reduction = 0     Weight Reduction = 0
                                        lbs.                     lbs.                     lbs.
----------------------------------------------------------------------------------------------------------------

    The baseline 2017 MY heavy-haul tractor would emit 57 grams of 
CO2 per ton-mile and consume 5.6 gallons of fuel per 1,000 
ton-mile. The agencies propose the heavy-haul standards shown in Table 
III-20. We welcome comment on the heavy-haul tractor technology path 
and standards proposed by the agencies.

           Table III-20--Proposed Heavy-Haul Tractor Standards
------------------------------------------------------------------------
                                             Heavy-haul tractor
                                  --------------------------------------
                                     2021 MY      2024 MY      2027 MY
------------------------------------------------------------------------
Grams of CO2 per Ton-Mile                   54           52           51
 Standard........................
Gallons of Fuel per 1,000 Ton-          5.3045       5.1081        5.010
 Mile............................
------------------------------------------------------------------------

    The technology costs associated with the proposed heavy-haul 
tractor standards are shown below in Table III-21. We welcome comment 
on the technology costs.

[[Page 40235]]



  Table III-21--Heavy-Haul Tractor Technology Incremental Costs in the
  2021, 2024, and 2027 Model Year \a\ \b\ Preferred Alternative vs. the
                          Less Dynamic Baseline
                           [2012$ per vehicle]
------------------------------------------------------------------------
                                     2021 MY      2024 MY      2027 MY
------------------------------------------------------------------------
Engine \c\.......................         $314         $904       $1,698
Tires............................           81           78           75
Tire inflation system............          180          330          314
Transmission.....................        3,969        5,883        6,797
Axle & axle lubes................           70          128          200
Air conditioning.................           45           82          117
Other vehicle technologies.......          174          318          302
    Total........................        4,833        7,723        9,503
------------------------------------------------------------------------
Notes:
\a\ Costs shown are for the specified model year and are incremental to
  the costs of a tractor meeting the phase 1 standards. These costs
  include indirect costs via markups along with learning impacts. For a
  description of the markups and learning impacts considered in this
  analysis and how it impacts technology costs for other years, refer to
  Chapter 2 of the draft RIA (see draft RIA 2.12).
\b\ Note that values in this table include adoption rates. Therefore,
  the technology costs shown reflect the average cost expected for each
  of the indicated tractor classes. To see the actual estimated
  technology costs exclusive of adoption rates, refer to Chapter 2 of
  the draft RIA (see draft RIA 2.12 in particular).
\c\ Engine costs are for a heavy HD diesel engine meant for a
  combination tractor.

(e) Consistency of the Proposed Tractor Standards With the Agencies' 
Legal Authority
    The proposed HD Phase 2 standards are based on adoption rates for 
technologies that the agencies regard, subject to consideration of 
public comment, as the maximum feasible for purposes of EISA Section 
32902 (k) and appropriate under CAA Section 202 (a) for the reasons 
given in Section III.D.2(b) through (d) above; see also draft RIA 
Chapter 2.4. The agencies believe these technologies can be adopted at 
the estimated rates for these standards within the lead time provided, 
as discussed in draft RIA Chapter 2. The 2021 and 2024 MY standards are 
phase-in standards on the path to the 2027 MY standards and were 
developed using less aggressive application rates and therefore have 
lower technology package costs than the 2027 MY standards. Moreover, we 
project the cost of these technologies would be rapidly recovered by 
operators due to the associated fuel savings, as shown in the payback 
analysis included in Section IX below. The cost per tractor to meet the 
proposed 2027 MY standards is projected to range between $10,000 and 
$13,000 (much or all of this would be mitigated by the fuel savings 
during the first two years of ownership). The agencies note that while 
the projected costs are significantly greater than the costs projected 
for Phase 1, we still consider that cost to be reasonable, especially 
given the relatively short payback period. In this regard the agencies 
note that the estimated payback period for tractors of less than two 
years \168\ is itself shorter than the estimated payback period for 
light duty trucks in the 2017-2025 light duty greenhouse gas standards. 
That period was slightly over three years, see 77 FR 62926-62927, which 
EPA found to be a highly reasonable given the usual period of ownership 
of light trucks is typically five years.\169\ The same is true here. 
Ownership of new tractors is customarily four to six years, meaning 
that the greenhouse gas and fuel consumption technologies pay for 
themselves early on and the purchaser sees overall savings in 
succeeding years--while still owning the vehicle.\170\ The agencies 
note further that the costs for each subcategory are relatively 
proportionate; that is, costs of any single tractor subcategory are not 
disproportionately higher (or lower) than any other. Although the 
proposal is technology-forcing (especially with respect to aerodynamic 
and tire rolling resistance improvements), the agencies believe that 
manufacturers retain leeway to develop alternative compliance paths, 
increasing the likelihood of the standards' successful implementation. 
The agencies also regard these reductions as cost-effective, even 
without considering payback period. The agencies estimate the cost per 
metric ton of CO2eq reduction without considering fuel 
savings to be $20 in 2030, and we estimate the cost per gallon of 
avoided fuel consumption to be about $0.25 per gallon, which compares 
favorably with the levels of cost effectiveness the agencies found to 
be reasonable for light duty trucks.171 172 See 77 FR 62922. 
The proposed phase-in 2021 and 2024 MY standards are less stringent and 
less costly than the proposed 2027 MY standards. For these reasons, and 
because the agencies have carefully considered lead time, EPA believes 
they are also reasonable under Section 202(a) of the CAA. Given that 
the agencies believe the proposed standards are technically feasible, 
are highly cost effective, and highly cost effective when accounting 
for the fuel savings, and have no apparent adverse potential impacts 
(e.g., there are no projected negative impacts on safety or vehicle 
utility), the proposed standards appear to represent a reasonable 
choice under Section 202(a) of the CAA and the maximum feasible under 
NHTSA's EISA authority at 49 U.S.C. 32902(k)(2).
---------------------------------------------------------------------------

    \168\ See Draft RIA Chapter 7.1.3.
    \169\ Auto Remarketing. Length of Ownership Returning to More 
Normal Levels; New Registrations Continue Slow Climb. April 1, 2013. 
Last accessed on February 26, 2015 at http://www.autoremarketing.com/trends/length-ownership-returning-more-normal-levels-new-registrations-continue-slow-climb.
    \170\ North American Council for Freight Efficiency. Barriers to 
Increased Adoption of Fuel Efficiency Technologies in Freight 
Trucking. July 2013. Page 24.
    \171\ See Draft RIA Chapter 7.1.4.
    \172\ If using a cost effectiveness metric that treats fuel 
savings as a negative cost, net costs per ton of GHG emissions 
reduced or per gallon of avoided fuel consumption would be negative 
under the proposed standards.
---------------------------------------------------------------------------

    Based on the information before the agencies, we currently believe 
that Alternative 3 would be maximum feasible and reasonable for the 
tractor segment for the model years in question. The agencies believe 
Alternative 4 has potential to be the maximum feasible and reasonable 
alternative; however, based on the evidence currently before us, EPA 
and NHTSA have outstanding questions regarding relative risks and 
benefits of Alternative 4 due to the timeframe envisioned by the 
alternative. Alternative 3 is generally designed to achieve the levels 
of fuel consumption and GHG reduction that Alternative 4 would achieve, 
but with several years of

[[Page 40236]]

additional lead-time--i.e., the Alternative 3 standards would end up in 
the same place as the Alternative 4 standards, but several years later, 
meaning that manufacturers could, in theory, apply new technology at a 
more gradual pace and with greater flexibility. However, Alternative 4 
would provide earlier GHG benefits compared to Alternative 3.
(f) Alternative Tractor Standards Considered
    The agencies developed and considered other alternative levels of 
stringency for the Phase 2 program. The results of the analysis of 
these alternatives are discussed below in Section X of the preamble. 
For tractors, the agencies developed the following alternatives as 
shown in Table III-22.

    Table III-22--Summary of Alternatives Considered for the Proposed
                               Rulemaking
------------------------------------------------------------------------
 
------------------------------------------------------------------------
Alternative 1.....................  No action alternative
Alternative 2.....................  Less Stringent than the Proposed
                                     Alternative applying off-the-shelf
                                     technologies.
Alternative 3 (Proposed             Proposed Alternative fully phased-in
 Alternative).                       by 2027 MY.
Alternative 4.....................  Alternative that pulls ahead the
                                     proposed 2027 MY standards to 2024
                                     MY.
Alternative 5.....................  Alternative based on very high
                                     market adoption of advanced
                                     technologies.
------------------------------------------------------------------------

    When evaluating the alternatives, it is necessary to evaluate the 
impact of a proposed regulation in terms of CO2 emission 
reductions, fuel consumption reductions, and technology costs. However, 
it is also necessary to consider other aspects, such as manufacturers' 
research and development resources, the impact on purchase price, and 
the impact on purchasers. Manufacturers are limited in their ability to 
develop and implement new technologies due to their human resources and 
budget constraints. This has a direct impact on the amount of lead time 
that is required to meet any new standards. From the owner/operator 
perspective, heavy-duty vehicles are a capital investment for firms and 
individuals so large increases in the upfront cost could impact buying 
patterns. Though the dollar value of the lifetime fuel savings will far 
exceed the upfront technology costs, purchasers often discount future 
fuel savings for a number of reasons. The purchaser often has 
uncertainty in the amount of fuel savings that can be expected for 
their specific operation due to the diversity of the heavy-duty tractor 
market. Although a nationwide perspective that averages out this 
uncertainty is appropriate for rulemaking analysis, individual 
operators must consider their potentially narrow operation. In 
addition, purchasers often put a premium on reliability (because 
downtime is costly in terms of towing, repair, late deliveries, and 
lost revenue) and may perceive any new technology as a potential risk 
with respect to reliability. Another factor that purchasers consider is 
the impact of a new technology on the resale market, which can also be 
impacted by uncertainty.
    The agencies selected the proposed standards over the more 
stringent alternatives based on considering the relevant statutory 
factors. In 2027, the proposed standards achieve up to a 24 percent 
reduction in CO2 emissions and fuel consumption compared to 
a Phase 1 tractor at a per vehicle cost of approximately $13,000. 
Alternative 4 achieves the same percent reduction in CO2 
emissions and fuel consumption compared to a Phase 1 tractor, but three 
years earlier, at a per vehicle cost of approximately $14,000. The 
alternative standards are projected to result in more emission and fuel 
consumption reductions from the heavy-duty tractors built in model 
years 2021 through 2026.\173\ We project the proposed standards to be 
achievable within known design cycles, and we believe these standards 
would allow different paths to compliance in addition to the one we 
outline and cost here.
---------------------------------------------------------------------------

    \173\ See Tables III-14 and III-27.
---------------------------------------------------------------------------

    The agencies solicit comment on all of these issues and again note 
the possibility of adopting, in a final action, standards that are more 
accelerated than those proposed in Alternative 3. The agencies are also 
assuming that both the proposed standards and Alternative 4 could be 
accomplished with all changes being made during manufacturers' normal 
product design cycles. However, we note that doing so would be more 
challenging for Alternative 4 and may require accelerated research and 
development outside of design cycles with attendant increased costs.
    The agencies are especially interested in seeking detailed comments 
on Alternative 4. Therefore, we are including the details of the 
Alternative 4 analysis below. The adoption rates considered for the 
2021 and 2024 MY standards developed for Alternative 4 are shown below 
in Table III-23 and Table III-24. The inputs to GEM used to develop the 
Alternative 4 CO2 and fuel consumption standards are shown 
below in Table III-25 and Table III-26. The standards associated with 
Alternative 4 are shown below in Table III-27. Commenters are 
encouraged to address all aspects of feasibility analysis, including 
costs, the likelihood of developing the technology to achieve 
sufficient relaibility within the proposed lead time, and the extent to 
which the market could utilize the technology.
(g) Derivation of Alternative 4 Tractor Standards
    The adoption rates considered for the 2021 and 2024 MY standards 
developed for Alternative 4 are shown below in Table III-23 and Table 
III-24. The inputs to GEM used to develop the Alternative 4 
CO2 and fuel consumption standards are shown below in Table 
III-25 and Table III-26. The standards associated with Alternative 4 
are shown below in Table III-27. Commenters are encouraged to address 
all aspects of feasibility analysis, including costs, the likelihood of 
developing the technology to achieve sufficient relaibility within the 
lead time.

[[Page 40237]]



                                                 Table III-23--Alternative 4 Adoption Rates for 2021 MY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    Class 7                                                    Class 8
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    Day cab                                Day cab                              Sleeper cab
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                       Low roof     Mid roof    High roof     Low roof     Mid roof    High roof     Low roof     Mid roof    High roof
                                         (%)          (%)          (%)          (%)          (%)          (%)          (%)          (%)          (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Alternative 4 2021MY Engine Technology Package
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                             100          100          100          100          100          100          100          100          100
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Aerodynamics
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bin I..............................            0            0            0            0            0            0            0            0            0
Bin II.............................           65           65            0           65           65            0           65           65            0
Bin III............................           30           30           35           30           30           35           30           30           35
Bin IV.............................            5            5           30            5            5           30            5            5           30
Bin V..............................          N/A          N/A           25          N/A          N/A           25          N/A          N/A           25
Bin VI.............................          N/A          N/A           10          N/A          N/A           10          N/A          N/A           10
Bin VII............................          N/A          N/A            0          N/A          N/A            0          N/A          N/A            0
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Steer Tires
--------------------------------------------------------------------------------------------------------------------------------------------------------
Base...............................            5            5            5            5            5            5            5            5            5
Level 1............................           35           35           35           35           35           35           35           35           35
Level 2............................           45           45           45           45           45           45           45           45           45
Level 3............................           15           15           15           15           15           15           15           15           15
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Drive Tires
--------------------------------------------------------------------------------------------------------------------------------------------------------
Base...............................            5            5            5            5            5            5            5            5            5
Level 1............................           35           35           35           35           35           35           35           35           35
Level 2............................           45           45           45           45           45           45           45           45           45
Level 3............................           15           15           15           15           15           15           15           15           15
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Extended Idle Reduction
--------------------------------------------------------------------------------------------------------------------------------------------------------
APU................................          N/A          N/A          N/A          N/A          N/A          N/A           80           80           80
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Transmission Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
Manual.............................           25           25           25           25           25           25           25           25           25
AMT................................           40           40           40           40           40           40           40           40           40
Auto...............................           30           30           30           30           30           30           30           30           30
Dual Clutch........................            5            5            5            5            5            5            5            5            5
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Driveline
--------------------------------------------------------------------------------------------------------------------------------------------------------
Axle Lubricant.....................           20           20           20           20           20           20           20           20           20
6x2 Axle...........................  ...........  ...........  ...........           10           10           20           10           10           30
Downspeed..........................           30           30           30           30           30           30           30           30           30
Direct Drive.......................           50           50           50           50           50           50           50           50           50
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Accessory Improvements
--------------------------------------------------------------------------------------------------------------------------------------------------------
A/C................................           20           20           20           20           20           20           20           20           20
Electric Access....................           20           20           20           20           20           20           20           20           20
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Other Technologies
--------------------------------------------------------------------------------------------------------------------------------------------------------
Predictive Cruise Control..........           30           30           30           30           30           30           30           30           30
--------------------------------------------------------------------------------------------------------------------------------------------------------
Automated Tire Inflation System....           30           30           30           30           30           30           30           30           30
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 40238]]


                                                 Table III-24--Alternative 4 Adoption Rates for 2024 MY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    Class 7                                                    Class 8
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    Day cab                                Day cab                              Sleeper cab
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                       Low roof     Mid roof    High roof     Low roof     Mid roof    High roof     Low roof     Mid roof    High roof
                                         (%)          (%)          (%)          (%)          (%)          (%)          (%)          (%)          (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Alternative 4 2024MY Engine Technology Package
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                             100          100          100          100          100          100          100          100          100
                                                                      Aerodynamics
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bin I..............................            0            0            0            0            0            0            0            0            0
Bin II.............................           50           50            0           50           50            0           50           50            0
Bin III............................           40           40           20           40           40           20           40           40           20
Bin IV.............................           10           10           20           10           10           20           10           10           20
Bin V..............................          N/A          N/A           35          N/A          N/A           35          N/A          N/A           35
Bin VI.............................          N/A          N/A           20          N/A          N/A           20          N/A          N/A           20
Bin VII............................          N/A          N/A            5          N/A          N/A            5          N/A          N/A            5
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Steer Tires
--------------------------------------------------------------------------------------------------------------------------------------------------------
Base...............................            5            5            5            5            5            5            5            5            5
Level 1............................           20           20           20           20           20           20           20           20           20
Level 2............................           50           50           50           50           50           50           50           50           50
Level 3............................           25           25           25           25           25           25           25           25           25
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Drive Tires
--------------------------------------------------------------------------------------------------------------------------------------------------------
Base...............................            5            5            5            5            5            5            5            5            5
Level 1............................           20           20           20           20           20           20           20           20           20
Level 2............................           50           50           50           50           50           50           50           50           50
Level 3............................           25           25           25           25           25           25           25           25           25
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Extended Idle Reduction
--------------------------------------------------------------------------------------------------------------------------------------------------------
APU................................          N/A          N/A          N/A          N/A          N/A          N/A           90           90           90
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Transmission Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
Manual.............................           10           10           10           10           10           10           10           10           10
AMT................................           50           50           50           50           50           50           50           50           50
Auto...............................           30           30           30           30           30           30           30           30           30
Dual Clutch........................           10           10           10           10           10           10           10           10           10
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Driveline
--------------------------------------------------------------------------------------------------------------------------------------------------------
Axle Lubricant.....................           40           40           40           40           40           40           40           40           40
6x2 Axle...........................  ...........  ...........  ...........           20           20           60           20           20           60
Downspeed..........................           60           60           60           60           60           60           60           60           60
Direct Drive.......................           50           50           50           50           50           50           50           50           50
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Accessory Improvements
--------------------------------------------------------------------------------------------------------------------------------------------------------
A/C................................           30           30           30           30           30           30           30           30           30
Electric Access....................           30           30           30           30           30           30           30           30           30
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Other Technologies
--------------------------------------------------------------------------------------------------------------------------------------------------------
Predictive Cruise Control..........           40           40           40           40           40           40           40           40           40
Automated Tire Inflation System....           40           40           40           40           40           40           40           40           40
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 40239]]


                                Table III-25--Alternative 4 GEM Inputs for 2021MY
----------------------------------------------------------------------------------------------------------------
               Class 7                                                  Class 8
----------------------------------------------------------------------------------------------------------------
               Day cab                                Day cab                             Sleeper cab
----------------------------------------------------------------------------------------------------------------
  Low roof     Mid roof    High roof     Low roof     Mid roof    High roof    Low roof    Mid roof    High roof
----------------------------------------------------------------------------------------------------------------
                                                     Engine
----------------------------------------------------------------------------------------------------------------
2021MY 11L   2021MY 11L   2021MY 11L   2021MY 15L   2021MY 15L   2021MY 15L   2021MY 15L  2021MY 15L  2021MY 15L
 Engine 350  Engine 350   Engine 350   Engine 455   Engine 455   Engine 455   Engine 455  Engine 455  Engine 455
     HP--2%      HP--2%       HP--2%       HP--2%       HP--2%       HP--2%      HP--2%      HP--2%      HP--2%
  reduction   reduction    reduction    reduction    reduction    reduction   reduction   reduction   reduction
----------------------------------------------------------------------------------------------------------------
                                           Aerodynamics (CdA in m\2\)
----------------------------------------------------------------------------------------------------------------
      4.61         6.01         5.83         4.61         6.01         5.83        4.61        6.01        5.63
----------------------------------------------------------------------------------------------------------------
                                       Steer Tires (CRR in kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       5.9          5.9          5.9          5.9          5.9          5.9         5.9         5.9         5.9
----------------------------------------------------------------------------------------------------------------
                                       Drive Tires (CRR in kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       6.2          6.2          6.2          6.2          6.2          6.2         6.2         6.2         6.2
----------------------------------------------------------------------------------------------------------------
                                 Extended Idle Reduction Weighted Effectiveness
----------------------------------------------------------------------------------------------------------------
       N/A          N/A          N/A          N/A          N/A          N/A        2.5%        2.5%        2.5%
----------------------------------------------------------------------------------------------------------------
                              Transmission = 10 speed Automated Manual Transmission
                    Gear Ratios = 12.8, 9.25, 6.76, 4.90, 3.58, 2.61, 1.89, 1.38, 1.00, 0.73
----------------------------------------------------------------------------------------------------------------
                                             Drive axle Ratio = 3.45
----------------------------------------------------------------------------------------------------------------
                                         6x2 Axle Weighted Effectiveness
----------------------------------------------------------------------------------------------------------------
       N/A          N/A          N/A         0.3%         0.3%         0.8%        0.3%        0.3%        0.8%
----------------------------------------------------------------------------------------------------------------
                                      Low Friction Axle Lubrication = 0.1%
----------------------------------------------------------------------------------------------------------------
                                           Transmission benefit = 1.5%
----------------------------------------------------------------------------------------------------------------
                                        Predictive Cruise Control = 0.6%
----------------------------------------------------------------------------------------------------------------
                                          Accessory Improvements = 0.2%
----------------------------------------------------------------------------------------------------------------
                                 Air Conditioner Efficiency Improvements = 0.1%
----------------------------------------------------------------------------------------------------------------
                                     Automatic Tire Inflation Systems = 0.3%
----------------------------------------------------------------------------------------------------------------
                                            Weight Reduction = 0 lbs
----------------------------------------------------------------------------------------------------------------
                    Direct Drive Weighted Efficiency = 1% for sleeper cabs; 0.8% for day cabs
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------


                                Table III-26--Alternative 4 GEM Inputs for 2024MY
----------------------------------------------------------------------------------------------------------------
               Class 7                                                  Class 8
----------------------------------------------------------------------------------------------------------------
               Day cab                                Day cab                             Sleeper cab
----------------------------------------------------------------------------------------------------------------
  Low roof     Mid roof    High roof     Low roof     Mid roof    High roof    Low roof    Mid roof    High roof
----------------------------------------------------------------------------------------------------------------
                                                     Engine
----------------------------------------------------------------------------------------------------------------
2021MY 11L   2021MY 11L   2021MY 11L   2021MY 15L   2021MY 15L   2021MY 15L   2021MY 15L  2021MY 15L  2021MY 15L
 Engine 350  Engine 350   Engine 350   Engine 455   Engine 455   Engine 455   Engine 455  Engine 455  Engine 455
     HP--4%      HP--4%       HP--4%       HP--4%       HP--4%       HP--4%      HP--4%      HP--4%      HP--4%
  reduction   reduction    reduction    reduction    reduction    reduction   reduction   reduction   reduction
----------------------------------------------------------------------------------------------------------------
                                           Aerodynamics (CdA in m\2\)
----------------------------------------------------------------------------------------------------------------
      4.52         5.92         5.52         4.52         5.92         5.52        4.52        5.92        5.32
----------------------------------------------------------------------------------------------------------------

[[Page 40240]]

 
                                       Steer Tires (CRR in kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       5.6          5.6          5.6          5.6          5.6          5.6         5.6         5.6         5.6
----------------------------------------------------------------------------------------------------------------
                                       Drive Tires (CRR in kg/metric ton)
----------------------------------------------------------------------------------------------------------------
       5.9          5.9          5.9          5.9          5.9          5.9         5.9         5.9         5.9
----------------------------------------------------------------------------------------------------------------
                                 Extended Idle Reduction Weighted Effectiveness
----------------------------------------------------------------------------------------------------------------
       N/A          N/A          N/A          N/A          N/A          N/A          3%          3%          3%
----------------------------------------------------------------------------------------------------------------
                              Transmission = 10 speed Automated Manual Transmission
                    Gear Ratios = 12.8, 9.25, 6.76, 4.90, 3.58, 2.61, 1.89, 1.38, 1.00, 0.73
----------------------------------------------------------------------------------------------------------------
                                             Drive axle Ratio = 3.2
----------------------------------------------------------------------------------------------------------------
                                         6x2 Axle Weighted Effectiveness
----------------------------------------------------------------------------------------------------------------
       N/A          N/A          N/A         0.5%         0.5%         1.5%        0.5%        0.5%        1.5%
----------------------------------------------------------------------------------------------------------------
                                      Low Friction Axle Lubrication = 0.2%
----------------------------------------------------------------------------------------------------------------
                                           Transmission benefit = 1.8%
----------------------------------------------------------------------------------------------------------------
                                        Predictive Cruise Control = 0.8%
----------------------------------------------------------------------------------------------------------------
                                          Accessory Improvements = 0.3%
----------------------------------------------------------------------------------------------------------------
                                 Air Conditioner Efficiency Improvements = 0.2%
----------------------------------------------------------------------------------------------------------------
                                     Automatic Tire Inflation Systems = 0.4%
----------------------------------------------------------------------------------------------------------------
                                            Weight Reduction = 0 lbs
----------------------------------------------------------------------------------------------------------------
                    Direct Drive Weighted Efficiency = 1% for sleeper cabs; 0.8% for day cabs
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------


      Table III-27--Tractor Standards Associated with Alternative 4
------------------------------------------------------------------------
                                            Day cab          Sleeper cab
------------------------------------------------------------------------
                                     Class 7      Class 8      Class 8
------------------------------------------------------------------------
                 2021 Model Year CO2 Grams per Ton-Mile
------------------------------------------------------------------------
Low Roof.........................           92           74           66
Mid Roof.........................          102           81           74
High Roof........................          104           82           73
------------------------------------------------------------------------
           2021 Model Year Gallons of Fuel per 1,000 Ton-Mile
------------------------------------------------------------------------
Low Roof.........................       9.0373       7.2692       6.4833
Mid Roof.........................      10.0196       7.9568       7.2692
High Roof........................      10.2161       8.0550       7.1709
------------------------------------------------------------------------
                 2024 Model Year CO2 Grams per Ton-Mile
------------------------------------------------------------------------
Low Roof.........................           87           70           62
Mid Roof.........................           96           76           69
High Roof........................           96           76           67
------------------------------------------------------------------------
      2024 Model Year and Later Gallons of Fuel per 1,000 Ton-Mile
------------------------------------------------------------------------
Low Roof.........................       8.5462       6.8762       6.0904
Mid Roof.........................       9.4303       7.4656       6.7780
High Roof........................       9.4303       7.4656       6.5815
------------------------------------------------------------------------


[[Page 40241]]

    The technology costs of achieving the reductions projected in 
Alternative 4 are included below in Table III-28 and Table III-29.

       Table III-28-Class 7 and 8 Tractor Technology Incremental Costs in the 2021 Model Year Alternative 4 vs. the Less Dynamic Baseline \a\ \b\
                                                                   (2012$ per vehicle)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Class 7                                      Class 8
                                                              ------------------------------------------------------------------------------------------
                                                                        Day cab                   Day cab                       Sleeper cab
                                                              ------------------------------------------------------------------------------------------
                                                                 Low/mid                   Low/mid
                                                                   roof      High roof       roof      High roof     Low roof     Mid roof    High roof
--------------------------------------------------------------------------------------------------------------------------------------------------------
Engine \c\...................................................         $656         $656         $656         $656         $656         $656         $656
Aerodynamics.................................................          769          632          769          632          740          740          665
Tires........................................................           50           11           83           18           61           61           18
Tire inflation system........................................          271          271          271          271          271          271          271
Transmission.................................................        6,794        6,794        6,794        6,794        6,794        6,794        6,794
Axle & axle lubes............................................           56           56           75           95           75           75          115
Idle reduction with APU......................................            0            0            0            0        2,449        2,449        2,449
Air conditioning.............................................           90           90           90           90           90           90           90
Other vehicle technologies...................................          261          261          261          261          261          261          261
                                                              ------------------------------------------------------------------------------------------
    Total....................................................        8,946        8,769        8,999        8,816       11,397       11,397       11,318
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\a\ Costs shown are for the 2021 model year and are incremental to the costs of a tractor meeting the Phase 1 standards. These costs include indirect
  costs via markups along with learning impacts. For a description of the markups and learning impacts considered in this analysis and how it impacts
  technology costs for other years, refer to Chapter 2 of the draft RIA (see draft RIA 2.12).
\b\ Note that values in this table include adoption rates. Therefore, the technology costs shown reflect the average cost expected for each of the
  indicated tractor classes. To see the actual estimated technology costs exclusive of adoption rates, refer to Chapter 2 of the draft RIA (see draft
  RIA 2.12 in particular).
\c\ Engine costs are for a heavy HD diesel engine meant for a combination tractor. The engine costs in this table are equal to the engine costs
  associated with the separate engine standard because both include the same set of engine technologies (see Section II.D.2.e).


       Table III-29-Class 7 and 8 Tractor Technology Incremental Costs in the 2024 Model Year Alternative 4 vs. the Less Dynamic Baseline \a\ \b\
                                                                   (2012$ per vehicle)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Class 7                                      Class 8
                                                              ------------------------------------------------------------------------------------------
                                                                        Day cab                   Day cab                       Sleeper cab
                                                              ------------------------------------------------------------------------------------------
                                                                 Low/mid                   Low/mid
                                                                   roof      High roof       roof      High roof     Low roof     Mid roof    High roof
--------------------------------------------------------------------------------------------------------------------------------------------------------
Engine \c\...................................................       $1,885       $1,885       $1,885       $1,885       $1,885       $1,885       $1,885
Aerodynamics.................................................          805          935          805          935          773          773          997
Tires........................................................           50           14           83           23           63           63           23
Tire inflation system........................................          330          330          330          330          330          330          330
Transmission.................................................        7,143        7,143        7,143        7,143        7,143        7,143        7,143
Axle & axle lubes............................................          102          102          138          210          138          138          210
Idle reduction with APU......................................            0            0            0            0        2,687        2,687        2,687
Air conditioning.............................................          123          123          123          123          123          123          123
Other vehicle technologies...................................          318          318          318          318          318          318          318
                                                              ------------------------------------------------------------------------------------------
    Total....................................................       10,757       10,851       10,826       10,968       13,461       13,461       13,717
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\a\ Costs shown are for the 2024 model year and are incremental to the costs of a tractor meeting the Phase 1 standards. These costs include indirect
  costs via markups along with learning impacts. For a description of the markups and learning impacts considered in this analysis and how it impacts
  technology costs for other years, refer to Chapter 2 of the draft RIA (see draft RIA 2.12).
\b\ Note that values in this table include adoption rates. Therefore, the technology costs shown reflect the average cost expected for each of the
  indicated tractor classes. To see the actual estimated technology costs exclusive of adoption rates, refer to Chapter 2 of the draft RIA (see draft
  RIA 2.12 in particular).
\c\ Engine costs are for a heavy HD diesel engine meant for a combination tractor. The engine costs in this table are equal to the engine costs
  associated with the separate engine standard because both include the same set of engine technologies (see Section II.D.2.e).

E. Proposed Compliance Provisions for Tractors

    In HD Phase 1, the agencies developed an entirely new program to 
assess the CO2 emissions and fuel consumption of tractors. 
The agencies propose to carry over many aspects of the Phase 1 
compliance approach, but are proposing to enhance several aspects of 
the compliance program. The sections below highlight the key areas that 
are the same and those that are different.
(1) HD Phase 2 Compliance Provisions That Remain the Same
    The regulatory structure considerations for Phase 2 are discussed 
in more detail above in Section II. We welcome comment on all aspects 
of the

[[Page 40242]]

compliance program including where we are not proposing any changes.
(a) Application and Certification Process
    For the Phase 2 proposed rule, the agencies are proposing to keep 
many aspects of the HD Phase 1 tractor compliance program. For example, 
the agencies propose to continue to use GEM (as revised for Phase 2), 
in coordination with additional component testing by manufacturers to 
determine the inputs, to determine compliance with the proposed fuel 
efficiency and CO2 standards. Another aspect that we propose 
to carry over is the overall compliance approach.
    In Phase 1 and as proposed in Phase 2, the general compliance 
process in terms of the pre-model year, during the model year, and post 
model year activities remain unchanged. The manufacturers would 
continue to be required to apply for certification through a single 
source, EPA, with limited sets of data and GEM results (see 40 CFR 
1037.205). EPA would issue certificates upon approval based on 
information submitted through the VERIFY database (see 40 CFR 
1037.255). In Phase 1, EPA and NHTSA jointly review and approve 
innovative technology requests, i.e. performance of any technology 
whose performance is not measured by the GEM simulation tool and is not 
in widespread use in the 2010 MY. For Phase 2, the agencies are 
proposing a similar process for allowing credits for off-cycle 
technologies that are not measured by the GEM simulation tool (see 
Section I.B.v. for a more detailed discussion of off-cycle requests). 
During the model year, the manufacturers would continue to generate 
certification data and conduct GEM runs on each of the vehicle 
configurations it builds. After the model year ends, the manufacturers 
would submit end of year reports to EPA that include the GEM results 
for all of the configurations it builds, along with credit/deficit 
balances if applicable (see 40 CFR 1037.250 and 1037.730). EPA and 
NHTSA would jointly coordinate on any enforcement action required.
(b) Compliance Requirements
    The agencies are also proposing not to change the following 
provisions:

 Useful life of tractors (40 CFR 1037.105(e) and 1037.106(e)) 
although added for NHTSA in Phase 2 (40 CFR 535.5)
 Emission-related warranty requirements (40 CFR 1037.120)
 Maintenance instructions, allowable maintenance, and amending 
maintenance instructions (40 CFR 1037.125 and 137.220)
 Deterioration factors (40 CFR 1037.205(l) and 1037.241(c))
 Vehicle family, subfamily, and configurations (40 CFR 
1037.230)
(c) Drive Cycles and Weightings
    In Phase 1, the agencies adopted three drive cycles used in GEM to 
evaluate the fuel consumption and CO2 emissions from various 
vehicle configurations. One of the cycles is the Transient mode of the 
California ARB Heavy Heavy-Duty Truck 5 Mode cycle. It is intended to 
broadly cover urban driving. The other two cycles represent highway 
driving at 55 mph and 65 mph.
    The agencies propose to maintain the existing drive cycles and 
weighting. For sleeper cabs, the weightings would remain 5 percent of 
the Transient cycle, 9 percent of the 55 mph cycle, and 86 percent of 
the 65 mph cycle. The day cab results would be weighted based on 19 
percent of the transient cycle, 17 percent of the 55 mph cycle, and 64 
percent of the 65 mph cycle (see 40 CFR 1037.510(c)). One key 
difference in the proposed drive cycles is the addition of grade, 
discussed below in Section III.E.2.
    The 55 mph and 65 mph drive cycles used in GEM assume constant 
speed operation at nominal vehicle speeds with downshifting occurring 
if road incline causes a predetermined drop in vehicle speed. In real-
world vehicle operation, traffic conditions and other factors may cause 
periodic operation at lower (e.g. creep) or variable vehicle speeds. 
The agencies therefore request comment on the need to include segments 
of lower or variable speed operation in the nominally 55 mph and 65 mph 
drive cycles used in GEM and how this may or may not impact the 
strategies manufacturers would develop. We also request data from fleet 
operators or others that may track vehicle speed operation of heavy-
duty tractors.
(d) Empty Weight and Payload
    The total weight of the tractor-trailer combination is the sum of 
the tractor curb weight, the trailer curb weight, and the payload. The 
total weight of a vehicle is important because it in part determines 
the impact of technologies, such as rolling resistance, on GHG 
emissions and fuel consumption. In Phase 2, we are proposing to carry 
over the total weight of the tractor-trailer combination used in GEM 
for Phase 1. The agencies developed the proposed tractor curb weight 
inputs for Phase 2 from actual tractor weights measured in two of EPA's 
Phase 1 test programs. The proposed trailer curb weight inputs were 
derived from actual trailer weight measurements conducted by EPA and 
from weight data provided to ICF International by the trailer 
manufacturers.\174\
---------------------------------------------------------------------------

    \174\ ICF International. Investigation of Costs for Strategies 
to Reduce Greenhouse Gas Emissions for Heavy-Duty On-road Vehicles. 
July 2010. Pages 4-15. Docket Number EPA-HQ-OAR-2010-0162-0044.
---------------------------------------------------------------------------

    There is a further issue of what payload weight to assign during 
compliance testing. In use, trucks operate at different weights at 
different times during their operations. The greatest freight transport 
efficiency (the amount of fuel required to move a ton of payload) would 
be achieved by operating trucks at the maximum load for which they are 
designed all of the time. However, this may not always be practicable. 
Delivery logistics may dictate partial loading. Some payloads, such as 
potato chips, may fill the trailer before it reaches the vehicle's 
maximum weight limit. Or full loads simply may not be available 
commercially. M.J. Bradley analyzed the Truck Inventory and Use Survey 
and found that approximately 9 percent of combination tractor miles 
travelled empty, 61 percent are ``cubed-out'' (the trailer is full 
before the weight limit is reached), and 30 percent are ``weighed out'' 
(operating weight equal 80,000 lbs which is the gross vehicle weight 
limit on the Federal Interstate Highway System or greater than 80,000 
lbs for vehicles traveling on roads outside of the interstate 
system).\175\
---------------------------------------------------------------------------

    \175\ M.J. Bradley & Associates. Setting the Stage for 
Regulation of Heavy-Duty Vehicle Fuel Economy and GHG Emissions: 
Issues and Opportunities. February 2009. Page 35. Analysis based on 
1992 Truck Inventory and Use Survey data, where the survey data 
allowed developing the distribution of loads instead of merely the 
average loads.
---------------------------------------------------------------------------

    The amount of payload that a tractor can carry depends on the 
category (or GVWR and GCWR) of the vehicle. For example, a typical 
Class 7 tractor can carry less payload than a Class 8 tractor. For 
Phase 1, the agencies used the Federal Highway Administration Truck 
Payload Equivalent Factors using Vehicle Inventory and Use Survey 
(VIUS) and Vehicle Travel Information System data to determine the 
payloads. FHWA's results indicated that the average payload of a Class 
8 vehicle ranged from 36,247 to 40,089 lbs, depending on the average 
distance travelled per day.\176\ The same study shows that Class 7 
vehicles carried between 18,674 and 34,210 lbs of payload also 
depending on average distance travelled per day. Based on

[[Page 40243]]

these data, the agencies are proposing to continue to prescribe a fixed 
payload of 25,000 lbs for Class 7 tractors and 38,000 lbs for Class 8 
tractors for certification testing. The agencies propose to continue to 
use a common payload for Class 8 day cabs and sleeper cabs as a 
predefined GEM input because the data available do not distinguish 
among Class 8 tractor types. These proposed payload values represent a 
heavily loaded trailer, but not maximum GVWR, since as described above 
the majority of tractors ``cube-out'' rather than ``weigh-out.''
---------------------------------------------------------------------------

    \176\ The U.S. Federal Highway Administration. Development of 
Truck Payload Equivalent Factor. Table 11. Last viewed on March 9, 
2010 at http://ops.fhwa.dot.gov/freight/freight_analysis/faf/faf2_reports/reports9/s510_11_12_tables.htm.
---------------------------------------------------------------------------

    Details of the proposed individual weight inputs by regulatory 
category, as shown in Table III-30, are included in draft RIA Chapter 
3. We welcome comment or new data to support changes to the tractor 
weights, or refinements to the heavy-haul tractor, trailer, and payload 
weights.

                            Table III-30--Proposed Combination Tractor Weight Inputs
----------------------------------------------------------------------------------------------------------------
                                  Regulatory     Tractor tare    Trailer weight                    Total weight
          Model type             subcategory     weight  (lbs)        (lbs)       Payload  (lbs)       (lbs)
----------------------------------------------------------------------------------------------------------------
Class 8......................  Sleeper Cab              19,000            13,500          38,000          70,500
                                High Roof.
Class 8......................  Sleeper Cab Mid          18,750            10,000          38,000          66,750
                                Roof.
Class 8......................  Sleeper Cab Low          18,500            10,500          38,000          67,000
                                Roof.
Class 8......................  Day Cab High             17,500            13,500          38,000          69,000
                                Roof.
Class 8......................  Day Cab Mid              17,100            10,000          38,000          65,100
                                Roof.
Class 8......................  Day Cab Low              17,000            10,500          38,000          65,500
                                Roof.
Class 7......................  Day Cab High             11,500            13,500          25,000          50,000
                                Roof.
Class 7......................  Day Cab Mid              11,100            10,000          25,000          46,100
                                Roof.
Class 7......................  Day Cab Low              11,000            10,500          25,000          46,500
                                Roof.
Class 8......................  Heavy-Haul.....          19,000            13,500          86,000         118,500
----------------------------------------------------------------------------------------------------------------

(e) Tire Testing
    In Phase 1, the manufacturers are required to input their tire 
rolling resistance coefficient into GEM. Also in Phase 1, the agencies 
adopted the provisions in ISO 28580 to determine the rolling resistance 
of tires. As described in 40 CFR 1037.520(c), the agencies require that 
at least three tires for each tire design are to be tested at least one 
time. Our assessment of the Phase 1 program to date indicates that 
these requirements reasonably balance the need for precision, 
repeatability, and testing burden. Therefore we propose to carry over 
the Phase 1 testing provisions for tire rolling resistance into Phase 
2. We welcome comments regarding the proposed tire testing provisions.
    In Phase 1, the agencies received comments from stakeholders 
highlighting a need to develop a reference lab and alignment tires for 
the HD sector. The agencies discussed the lab-to-lab comparison 
conducted in the Phase 1 EPA tire test program (76 FR 57184). The 
agencies reviewed the rolling resistance data from the tires that were 
tested at both the STL and Smithers laboratories to assess inter-
laboratory and test machine variability. The agencies conducted 
statistical analysis of the data to gain better understanding of lab-
to-lab correlation and developed an adjustment factor for data measured 
at each of the test labs. Based on these results, the agencies believe 
the lab-to-lab variation for the STL and Smithers laboratories would 
have very small effect on measured rolling resistance values. Based on 
the test data, the agencies judge for the HD Phase 2 program to 
continue to use the current levels of variability, and the agencies 
therefore propose to allow the use of either Smithers or STL 
laboratories for determining the tire rolling resistance value. 
However, we welcome comment on the need to establish a reference 
machine for the HD sector and whether tire testing facilities are 
interested in and willing to commit to developing a reference machine.
(2) Key Differences in HD Phase 2 Compliance Provisions
    We welcome comment on all aspects of the compliance program for 
which we are proposing changes.
(a) Aerodynamic Assessment
    In Phase 1, the manufacturers conduct aerodynamic testing to 
establish the appropriate bin and GEM input for determining compliance 
with the CO2 and fuel consumption standards. The agencies 
propose to continue this general approach in HD Phase 2, but make 
several enhancements to the aerodynamic assessment of tractors. As 
discussed below in this section, we propose some modifications to the 
aerodynamic test procedures--the addition of wind averaged yaw in the 
aerodynamic assessment, the addition of trailer skirts to the standard 
trailer used to determine aerodynamic performance of tractors and 
revisions to the aerodynamic bins.
(i) Aerodynamic Test Procedures
    The aerodynamic drag of a vehicle is determined by the vehicle's 
coefficient of drag (Cd), frontal area, air density and speed. 
Quantifying tractor aerodynamics as an input to the GEM presents 
technical challenges because of the proliferation of tractor 
configurations, and subtle variations in measured aerodynamic values 
among various test procedures. In Phase 1, Class 7 and 8 tractor 
aerodynamic results are developed by manufacturers using a range of 
techniques, including wind tunnel testing, computational fluid 
dynamics, and constant speed tests.
    We continue to believe a broad approach allowing manufacturers to 
use these multiple test procedures to demonstrate aerodynamic 
performance of its tractor fleet is appropriate given that no single 
test procedure is superior in all aspects to other approaches. However, 
we also recognize the need for consistency and a level playing field in 
evaluating aerodynamic performance. To address the consistency and 
level playing field concerns, NHTSA and EPA adopted in Phase 1, while 
working with industry, an approach that identified a reference 
aerodynamic test method and a procedure to align results from other 
aerodynamic test procedures with the reference method.
    The agencies adopted in Phase 1 an enhanced coastdown procedure as 
the reference method (see 40 CFR 1066.310) and defined a process for 
manufacturers to align drag results from each of their own test methods 
to the reference method results using Falt-aero (see 40 CFR 1037.525). 
Manufacturers are able to use any aerodynamic evaluation method in 
demonstrating a vehicle's aerodynamic performance as long as the method 
is aligned to the reference method. The agencies propose to continue to 
use this alignment method

[[Page 40244]]

approach to maintain the testing flexibility that manufacturers have 
today. However, the agencies propose to increase the rigor in 
determining the Falt-aero for Phase 2. Beginning in 2021 MY, we propose 
that the manufacturers would be required to determine a new Falt-aero 
for each of their tractor models for each aerodynamic test method. In 
Phase 1, manufacturers are required to determine their Falt-aero using 
only a high roof sleeper cab with a full aerodynamics package (see 40 
CFR 1037.521(a)(2) and proposed 40 CFR 1037.525(b)(2)). In Phase 2, we 
propose that manufacturers would be required to determine a unique 
Falt-aero value for each major model of their high roof day cabs and 
high roof sleeper cabs. In Phase 2, we propose that manufacturers may 
carry over the Falt-aero value until a model changeover or based on the 
agencies' discretion to require up to six new Falt-aero determinations 
each year. We welcome comment on the burden associated with this 
proposed change to conduct up to six coastdown tests per year per 
manufacturer.
    Based on feedback received during the development of Phase 1, we 
understand that there is interest from some manufacturers to change the 
reference method in Phase 2 from coastdown to constant speed testing. 
EPA has conducted an aerodynamic test program at Southwest Research 
Institute to evaluate both methods in terms of cost of testing, testing 
time, testing facility requirements, and repeatability of results. 
Details of the analysis and results are included in draft RIA Chapter 
3.2. The results showed that the enhanced coastdown test procedures and 
analysis produced results with acceptable repeatability and at a lower 
cost than the constant speed testing. Based on the results of this 
testing, the agencies propose to continue to use the enhanced coastdown 
procedure for the reference method in Phase 2.\177\ However, we welcome 
comment on the need to change the reference method for the Phase 2 
final rule to constant speed testing, including comparisons of 
aerodynamic test results using both the coastdown and constant speed 
test procedures. In addition, we welcome comments on and suggested 
revisions to the constant speed test procedure specifications set forth 
in Chapter 3.2.2.2 of the draft RIA and 40 CFR 1037.533. If we 
determine that it is appropriate to make the change, then the 
aerodynamic bins in the final rule would be adjusted to take into 
account the difference in absolute CdA values due to the change in 
method.
---------------------------------------------------------------------------

    \177\ Southwest Research Institute. ``Heavy Duty Class 8 Truck 
Coastdown and Constant Speed Testing.'' April 2015.
---------------------------------------------------------------------------

    The agencies are also considering refinements to the computational 
fluid dynamics modeling method to determine the aerodynamic performance 
of tractors. Specifically, we are considering whether the conditions 
for performing the analysis require greater specificity (e.g., wind 
speed and direction inclusion, turbulence intensity criteria value) or 
if turbulence model and mesh deformation should be required, rather 
than ``if applicable,'' for all CFD analysis.\178\ The agencies welcome 
comment on the proposed revisions.
---------------------------------------------------------------------------

    \178\ 40 CFR 1037.531 ``Computational fluid dynamics (CFD)''.
---------------------------------------------------------------------------

    In Phase 1, we adopted interim provisions in 40 CFR 1037.150(k) 
that accounted for coastdown measurement variability by allowing a 
compliance demonstration based on in-use test results if the drag area 
was at or below the maximum drag area allowed for the bin above the bin 
to which the vehicle was certified. Since adoption of Phase 1, EPA has 
conducted in-use aerodynamic testing and found that uncertainty 
associated with coastdown testing is less than anticipated.\179\ In 
addition, we are proposing additional enhancements in the Phase 2 
coastdown procedures to continue to reduce the variability of coastdown 
results, including the impact of environmental conditions. Therefore, 
we are proposing to sunset the provision in 40 CFR 1037.150(k) at the 
end of the Phase 1 program (after the 2020 model year). We request 
comment on whether or not we should factor in a test variability 
compliance margin into the aerodynamic test procedure, and therefore 
request data on aerodynamic test variability.
---------------------------------------------------------------------------

    \179\ Southwest Research Institute. ``Heavy Duty Class 8 Truck 
Coastdown and Constant Speed Testing.'' April 2015.
---------------------------------------------------------------------------

(ii) Wind Averaged Drag
    In Phase 1, EPA and NHTSA recognized that wind conditions, most 
notably wind direction, have a greater impact on real world 
CO2 emissions and fuel consumption of heavy-duty trucks than 
of light-duty vehicles.\180\ As noted in the NAS report, the wind 
average drag coefficient is about 15 percent higher than the zero 
degree coefficient of drag.\181\ In addition, the agencies received 
comments in Phase 1 that supported the use of wind averaged drag 
results for the aerodynamic determination. The agencies considered 
adopting the use of a wind averaged drag coefficient in the Phase 1 
regulatory program, but ultimately decided to finalize drag values 
which represent zero yaw (i.e., representing wind from directly in 
front of the vehicle, not from the side) instead. We took this approach 
recognizing that the reference method is coastdown testing and it is 
not capable of determining wind averaged yaw.\182\ Wind tunnels and CFD 
are currently the only tools to accurately assess the influence of wind 
speed and direction on a truck's aerodynamic performance. The agencies 
recognized, as NAS did, that the results of using the zero yaw approach 
may result in fuel consumption predictions that are offset slightly 
from real world performance levels, not unlike the offset we see today 
between fuel economy test results in the CAFE program and actual fuel 
economy performance observed in-use.
---------------------------------------------------------------------------

    \180\ See 2010 NAS Report, page 95
    \181\ See 2010 NAS Report, Finding 2-4 on page 39. Also see 2014 
NAS Report, Recommendation 3.5.
    \182\ See 2010 NAS Report. Page 95.
---------------------------------------------------------------------------

    As the tractor manufacturers continue to refine the aerodynamics of 
tractors, we believe that continuing the zero yaw approach into Phase 2 
could potentially impact the overall technology effectiveness or change 
the kinds of technology decisions made by the tractor manufacturers in 
developing equipment to meet our proposed HD Phase 2 standards. 
Therefore, we are proposing aerodynamic test procedures that take into 
account the wind averaged drag performance of tractors. The agencies 
propose to account for this change in aerodynamic test procedure by 
appropriately adjusting the aerodynamic bins to reflect a wind averaged 
drag result instead of a zero yaw result.
    The agencies propose that beginning in 2021 MY, the manufacturers 
would be required to adjust their CdA values to represent a zero yaw 
value from coastdown and add the CdA impact of the wind averaged drag. 
The impact of wind averaged drag relative to a zero yaw condition can 
only be measured in a wind tunnel or with CFD. We welcome data 
evaluating the consistency of wind averaged drag measurements between 
wind tunnel, CFD, and other potential methods such as constant speed or 
coastdown. The agencies propose that manufacturers would use the 
following equation to make the necessary adjustments to a coastdown 
result to obtain the CdAwad value:

CdAwad = CdAzero,coastdown + 
(CdAwad,wind tunnel-CdAzero,wind tunnel) * 
Falt-aero

    If the manufacturer has a wind averaged CdA value from either a 
wind tunnel or CFD, then we propose they

[[Page 40245]]

would use the following equation to obtain the CdAwad value:

CdAwad = CdAwad,wind tunnel or CFD * 
Falt-aero

    We welcome comment on whether the wind averaged drag should be 
determined using a full yaw sweep as specified in Appendix A of the 
Society of Automotive Engineers (SAE) recommended practice number J1252 
``SAE Wind Tunnel Test Procedure for Trucks and Buses'' (e.g., zero 
degree yaw and a six other yaw angles at increments of 3 degrees or 
greater) or a subset of specific angles as currently allowed in the 
Phase 1 regulations.\183\
---------------------------------------------------------------------------

    \183\ Proposed 40 CFR 1037.525(d)(2); ``Yaw Sweep Corrections''.
---------------------------------------------------------------------------

    To reduce the testing burden the agencies propose that 
manufacturers have the option of determining the offset between zero 
yaw and wind averaged yaw either through testing or by using the EPA-
defined default offset. Details regarding the determination of the 
offset are included in the draft RIA Chapter 3.2. We propose the 
manufacturers would use the following equation if they had a zero yaw 
coastdown value and choose not to conduct wind averaged measurements.

CdAwad = CdAzero,coastdown + 0.80

    In addition, we propose the manufacturers would use the following 
equation if they had a zero yaw wind tunnel or CFD value and choose not 
to conduct wind averaged measurements.

CdAwad = (CdAzero,wind tunnel or CFD * 
Falt-aero)+0.80
    We welcome comments on all aspects of the proposed wind averaged 
drag provisions.
(iii) Standard Trailer Definition
    Similar to the approach the agencies adopted in Phase 1, NHTSA and 
EPA are proposing provisions such that the tractor performance in GEM 
is judged assuming the tractor is pulling a standardized trailer.\184\ 
The agencies believe that an assessment of the tractor fuel consumption 
and CO2 emissions should be conducted using a tractor-
trailer combination, as tractors are invariably used in combination 
with trailers and this is their essential commercial purpose. Trailers, 
of course, also influence the extent of carbon emissions from the 
tractor (and vice-versa). We believe that using a standardized trailer 
best reflects the impact of the overall weight of the tractor-trailer 
and the aerodynamic technologies in actual use, and consequent real-
world performance, where tractors are designed and used with a trailer. 
EPA research confirms what one would intuit: tractor-trailer pairings 
are almost always optimized. EPA conducted an evaluation of over 4,000 
tractor-trailer combinations using live traffic cameras in 2010.\185\ 
The results showed that approximately 95 percent of the tractors were 
matched with the standard trailer specified (high roof tractor with box 
trailer, mid roof tractor with tanker trailer, and low roof with 
flatbed trailer). Therefore, the agencies propose that Phase 2 GEM 
continue to use a predefined typical trailer defined in Phase 1 in 
assessing overall performance for test purposes. As such, the high roof 
tractors would be paired with a standard box trailer; the mid roof 
tractors would be paired with a tanker trailer; and the low roof 
tractors would be paired with a flatbed trailer.
---------------------------------------------------------------------------

    \184\ See 40 CFR 1037.501(g).
    \185\ See Memo to Docket, Amy Kopin. ``Truck and Trailer Roof 
Match Analysis.'' August 2010.
---------------------------------------------------------------------------

    However, the agencies are proposing to change the definition of the 
standard box trailer used by tractor manufacturers to determine the 
aerodynamic performance of high roof tractors in Phase 2. We believe 
this is necessary to reflect the aerodynamic improvements experienced 
by the trailer fleet over the last several years due to influences from 
the California Air Resources Board mandate \186\ and EPA's SmartWay 
Transport Partnership. The standard box trailer used in Phase 1 to 
assess the aerodynamic performance of high roof tractors is a 53 foot 
box trailer without any aerodynamic devices. In the development of 
Phase 2, the agencies evaluated the increase in adoption rates of 
trailer side skirts and boat tails in the market over the last several 
years and have seen a marked increase. We estimate that approximately 
50 percent of the new trailers sold in 2018 will have trailer side 
skirts.187 188 As the agencies look towards the proposed 
standards in the 2021 and beyond timeframe, we believe that it is 
appropriate to update the standard box trailer definition. In 2021-
2027, we believe the trailer fleet will be a mix of trailers with no 
aerodynamics, trailers with skirts, and trailers with advanced aero; 
with the advanced aero being a very limited subset of the new trailers 
sold each year. Consequently, overall, we believe a trailer with a 
skirt will be the most representative of the trailer fleet for the 
duration of the regulation timeframe, and plausibly beyond. Therefore, 
we are proposing that the standard box trailer in Phase 2--the trailer 
assumed during the certification process to be paired with a high roof 
tractor--be updated to include a trailer skirt starting in 2021 model 
year. Even though the agencies are proposing new box trailer standards 
beginning in 2018 MY, we are not proposing to update the standard 
trailer in the tractor certification process until 2021 MY, to align 
with the new tractor standards. If we were to revise the standardized 
trailer definition for Phase 1, then we would need to revise the Phase 
1 tractor standards. The details of the trailer skirt definition are 
included in 40 CFR 1037.501(g)(1).
---------------------------------------------------------------------------

    \186\ California Air Resources Board. Tractor-Trailer Greenhouse 
Gas regulation. Last viewed on September 4, 2014 at http://www.arb.ca.gov/msprog/truckstop/trailers/trailers.htm.
    \187\ Ben Sharpe (ICCT) and Mike Roeth (North American Council 
for Freight Efficiency), ``Costs and Adoption Rates of Fuel-Saving 
Technologies for Trailer in the North American On-Road Freight 
Sector'', Feb 2014.
    \188\ Frost & Sullivan, ``Strategic Analysis of North American 
Semi-trailer Advanced Technology Market'', Feb 2013.
---------------------------------------------------------------------------

    EPA has conducted extensive aerodynamic testing to quantify the 
impact on the coefficient of drag of a high roof tractor due to the 
addition of a trailer skirt. Details of the test program and the 
results can be found in the draft RIA Chapter 3.2. The results of the 
test program indicate that on average, the impact of a trailer skirt 
matching the definition of the skirt specified in 40 CFR 1037.501(g)(1) 
is approximately 8 percent improvement in coefficient of drag area. 
This off-set was used during the development of the Phase 2 aerodynamic 
bins.
    We seek comment on our proposed HD Phase 2 standard trailer 
configuration. We also welcome comments on suggestions on alternative 
ways to define the standard trailer, such as developing a certified 
computer aided drawing (CAD) model.
(iv) Aerodynamic Bins
    The agencies are proposing to continue the approach where the 
manufacturer would determine a tractor's aerodynamic drag force through 
testing, determine the appropriate predefined aerodynamic bin, and then 
input the predefined CdA value for that bin into the GEM. The agencies 
proposed Phase 2 aerodynamic bins reflect three changes to the Phase 1 
bins--the incorporation of wind averaged drag, the addition of trailer 
skirts to the standard box trailer used to determine the aerodynamic 
performance of high roof tractors, and the addition of bins to reflect 
the continued improvement of tractor aerodynamics in the future. 
Because of each of these changes, the aerodynamic bins proposed for 
Phase 2 are not directly comparable to the Phase 1 bins.
    HD Phase 1 included five aerodynamic bins to cover the spectrum of 
aerodynamic performance of high

[[Page 40246]]

roof tractors. Since the development of the Phase 1 rules, the 
manufacturers have continued to invest in aerodynamic improvements for 
tractors. This continued evolution of aerodynamic performance, both in 
production and in the research stage as part of the SuperTruck program, 
has consequently led the agencies to propose two additional aerodynamic 
technology bins (Bins VI and VII) for high roof tractors. These two new 
bins would further segment the Phase 1 aerodynamic Bin V to recognize 
the difference in advanced aerodynamic technologies and designs.
    In both HD Phase 1 and as proposed by the agencies in Phase 2, 
aerodynamic Bin I through Bin V represent tractors sharing similar 
levels of technology. The first high roof aerodynamic category, Bin I, 
is designed to represent tractor bodies which prioritize appearance or 
special duty capabilities over aerodynamics. These Bin I tractors 
incorporate few, if any, aerodynamic features and may have several 
features that detract from aerodynamics, such as bug deflectors, custom 
sunshades, B-pillar exhaust stacks, and others. The second high roof 
aerodynamics category is Bin II which roughly represents the 
aerodynamic performance of the average new tractor sold in 2010. The 
agencies developed this bin to incorporate conventional tractors which 
capitalize on a generally aerodynamic shape and avoid classic features 
which increase drag. High roof tractors within Bin III build on the 
basic aerodynamics of Bin II tractors with added components to reduce 
drag in the most significant areas on the tractor, such as integral 
roof fairings, side extending gap reducers, fuel tank fairings, and 
streamlined grill/hood/mirrors/bumpers, similar to 2013 model year 
SmartWay tractors. The Bin IV aerodynamic category for high roof 
tractors builds upon the Bin III tractor body with additional 
aerodynamic treatments such as underbody airflow treatment, down 
exhaust, and lowered ride height, among other technologies. HD Phase 1 
Bin V tractors incorporate advanced technologies which are currently in 
the prototype stage of development, such as advanced gap reduction, 
rearview cameras to replace mirrors, wheel system streamlining, and 
advanced body designs. For HD Phase 2, the agencies propose to segment 
the aerodynamic performance of these advanced technologies into Bins V 
through VII.
    In Phase 1, the agencies adopted only two aerodynamic bins for low 
and mid roof tractors. The agencies limited the number of bins to 
reflect the actual range of aerodynamic technologies effective in low 
and mid roof tractor applications. High roof tractors are consistently 
paired with box trailer designs, and therefore manufacturers can design 
the tractor aerodynamics as a tractor-trailer unit and target specific 
areas like the gap between the tractor and trailer. In addition, the 
high roof tractors tend to spend more time at high speed operation 
which increases the impact of aerodynamics on fuel consumption and GHG 
emissions. On the other hand, low and mid roof tractors are designed to 
pull variable trailer loads and shapes. They may pull trailers such as 
flat bed, low boy, tankers, or bulk carriers. The loads on flat bed 
trailers can range from rectangular cartons with tarps, to a single 
roll of steel, to a front loader. Due to these variables, manufacturers 
do not design unique low and mid roof tractor aerodynamics but instead 
use derivatives from their high roof tractor designs. The aerodynamic 
improvements to the bumper, hood, windshield, mirrors, and doors are 
developed for the high roof tractor application and then carried over 
into the low and mid roof applications. As mentioned above, the types 
of designs that would move high roof tractors from a Bin III to Bins IV 
through VII include features such as gap reducers and integral roof 
fairings which would not be appropriate on low and mid roof tractors.
    As Phase 2 looks to further improve the aerodynamics for high roof 
sleeper cabs, we believe it is also appropriate to expand the number of 
bins for low and mid roof tractors too. For Phase 2, the agencies are 
proposing to differentiate the aerodynamic performance for low and mid 
roof applications with four bins, instead of two, in response to 
feedback received from manufacturers of low and mid roof tractors 
related to the limited opportunity to incorporate aerodynamic 
technologies in their compliance plan. We propose that low and mid roof 
tractors may determine the aerodynamic bin based on the aerodynamic bin 
of an equivalent high roof tractor, as shown below in Table III-31.

    Table III-31--Proposed Phase 2 Revisions to 40 CFR 1037.520(b)(3)
------------------------------------------------------------------------
            High roof bin                    Low and mid roof bin
------------------------------------------------------------------------
Bin I                                 Bin I
Bin II                                Bin I
Bin III                               Bin II
Bin IV                                Bin II
Bin V                                 Bin III
Bin VI                                Bin III
Bin VII                               Bin IV
------------------------------------------------------------------------

    The agencies developed new high roof tractor aerodynamic bins for 
Phase 2 that reflect the change from zero yaw to wind averaged drag, 
the more aerodynamic reference trailer, and the addition of two bins. 
Details regarding the derivation of the proposed high roof bins are 
included in Draft RIA Chapter 3.2.8. The proposed high roof tractor 
bins are defined in Table III-32. The proposed revisions to the low and 
mid roof tractor bins reflect the addition of two new aerodynamic bins 
and are listed in Table III-33.

 Table III-32--Proposed Phase 2 Aerodynamic Input Definitions to GEM for
                           High Roof Tractors
------------------------------------------------------------------------
                                     Class 7             Class 8
                                  --------------------------------------
                                     Day cab      Day cab    Sleeper cab
                                  --------------------------------------
                                    High roof    High roof    High roof
------------------------------------------------------------------------
                Aerodynamic Test Results (CdAwad in m\2\)
------------------------------------------------------------------------
Bin I............................        >=7.5        >=7.5        >=7.3
Bin II...........................      6.8-7.4      6.8-7.4      6.6-7.2
Bin III..........................      6.2-6.7      6.2-6.7      6.0-6.5
Bin IV...........................      5.6-6.1      5.6-6.1      5.4-5.9
Bin V............................      5.1-5.5      5.1-5.5      4.9-5.3
Bin VI...........................      4.7-5.0      4.7-5.0      4.5-4.8
Bin VII..........................        <=4.6        <=4.6        <=4.4
------------------------------------------------------------------------

[[Page 40247]]

 
                Aerodynamic Input to GEM (CdAwad in m\2\)
------------------------------------------------------------------------
Bin I............................          7.6          7.6          7.4
Bin II...........................          7.1          7.1          6.9
Bin III..........................          6.5          6.5          6.3
Bin IV...........................          5.8          5.8          5.6
Bin V............................          5.3          5.3          5.1
Bin VI...........................          4.9          4.9          4.7
Bin VII..........................          4.5          4.5          4.3
------------------------------------------------------------------------


        Table III-33--Proposed Phase 2 Aerodynamic Input Definitions to GEM for Low and Mid Roof Tractors
----------------------------------------------------------------------------------------------------------------
                                             Class 7                                Class 8
                                   -----------------------------------------------------------------------------
                                             Day cab                   Day cab                 Sleeper cab
                                   -----------------------------------------------------------------------------
                                      Low roof     Mid roof     Low roof     Mid roof     Low roof     Mid roof
----------------------------------------------------------------------------------------------------------------
                                     Aerodynamic Test Results (CdA in m\2\)
----------------------------------------------------------------------------------------------------------------
Bin I.............................        >=5.1        >=6.5        >=5.1        >=6.5        >=5.1        >=6.5
Bin II............................      4.6-5.0      6.0-6.4      4.6-5.0      6.0-6.4      4.6-5.0      6.0-6.4
Bin III...........................      4.2-4.5      5.6-5.9      4.2-4.5      5.6-5.9      4.2-4.5      5.6-5.9
Bin IV............................        <=4.1        <=5.5        <=4.1        <=5.5        <=4.1        <=5.5
----------------------------------------------------------------------------------------------------------------
                                     Aerodynamic Input to GEM (CdA in m\2\)
----------------------------------------------------------------------------------------------------------------
Bin I.............................          5.3          6.7          5.3          6.7          5.3          6.7
Bin II............................          4.8          6.2          4.8          6.2          4.8          6.2
Bin III...........................          4.3          5.7          4.3          5.7          4.3          5.7
Bin IV............................          4.0          5.4          4.0          5.4          4.0          5.4
----------------------------------------------------------------------------------------------------------------

(b) Road Grade in the Drive Cycles
    Road grade can have a significant impact on the overall fuel 
economy of a heavy-duty vehicle. Table III-34 shows the results from a 
real world evaluation of heavy-duty tractor-trailers conducted by Oak 
Ridge National Lab.\189\ The study found that the impact of a mild 
upslope of one to four percent led to a decrease in average fuel 
economy from 7.33 mpg to 4.35 mpg. These results are as expected 
because vehicles consume more fuel while driving on an upslope than 
driving on a flat road because the vehicle needs to exert additional 
power to overcome the grade resistance force.\190\ The amount of extra 
fuel increases with increases in road gradient. On downgrades, vehicles 
consume less fuel than on a flat road. However, as shown in the fuel 
consumption results in Table III-34, the amount of increase in fuel 
consumption on an upslope is greater than the amount of decrease in 
fuel consumption on a downslope which leads to a net increase in fuel 
consumption. As an example, the data shows that a vehicle would use 0.3 
gallons per mile more fuel in a severe upslope than on flat terrain, 
but only save 0.1 gallons of fuel per mile on a severe downslope. In 
another study, Southwest Research Institute modeling found that the 
addition of road grade to a drive cycle has an 8 to 10 percent negative 
impact on fuel economy.\191\
---------------------------------------------------------------------------

    \189\ Oakridge National Laboratory. Transportation Energy Book, 
Edition 33. Table 5.10 Effect of Terrain on Class 8 Truck Fuel 
Economy. 2014. Last accessed on September 19, 2014 at http://cta.ornl.gov/data/Chapter5.shtml.
    \190\ Ibid.
    \191\ Reinhart, T. (2015). Commercial Medium- and Heavy-Duty 
(MD/HD) Truck Fuel Efficiency Technology Study--Report #2. 
Washington, DC: National Highway Traffic Safety Administration.

          Table III-34--Fuel Consumption Relative to Road Grade
------------------------------------------------------------------------
                                  Average fuel          Average fuel
       Type of terrain         economy  (miles per       consumption
                                     gallon)         (gallons per mile)
------------------------------------------------------------------------
Severe upslope (>4%)........                  2.90                  0.34
Mild upslope (1% to 4%).....                  4.35                  0.23
Flat terrain (1% to 1%).....                  7.33                  0.14
Mild downslope (-4% to -1%).                 15.11                  0.07
Severe downslope (<-4%).....                 23.50                  0.04
------------------------------------------------------------------------


[[Page 40248]]

    In Phase 1, the agencies did not include road grade. However, we 
believe it is important to propose including road grade in Phase 2 to 
properly assess the value of technologies, such as downspeeding and the 
integration of the engine and transmission, which were not technologies 
included in the technology basis for Phase 1 and are not directly 
assessed by GEM in its Phase 1 iteration. The addition of road grade to 
the drive cycles would be consistent with the NAS recommendation in the 
2014 Phase 2 First Report.\192\
---------------------------------------------------------------------------

    \192\ National Academy of Science. ``Reducing the Fuel 
Consumption and GHG Emissions of Medium- and Heavy-Duty Vehicles, 
Phase Two, First Report.'' 2014. Recommendation S.3 (3.6).
---------------------------------------------------------------------------

    The U.S. Department of Energy and EPA have partnered to support a 
project aimed at evaluating, refining and/or developing the appropriate 
road grade profiles for the 55 mph and 65 mph highway cruise duty 
cycles that would be used in the certification of heavy-duty vehicles 
to the Phase 2 GHG emission and fuel efficiency standards. The National 
Renewable Energy Laboratory (NREL) was contracted to do this work and 
has since developed two pairs of candidate, activity-weighted road 
grade profiles representative of U.S. limited-access highways. To this 
end, NREL used high-accuracy road grade data and county-specific 
vehicle miles traveled data. One pair of the profiles is representative 
of the nation's limited-access highways with 55 and 60 mph speed 
limits, and another is representative of such highways with speed 
limits of 65 to 75 mph. The profiles are distance-based and cover a 
maximum distance of 12 and 15 miles, respectively. A report documenting 
this NREL work is in the public docket for these proposed rules, and 
comments are requested on the recommendations therein.\193\ In addition 
to NREL work, the agencies have independently developed yet another 
candidate road grade profile for use in the 55 mph and 65 mph highway 
cruise duty cycles. While based on the same road grade database 
generated by NREL for U.S. restricted-access highways, its design is 
predicated on a different approach. The development of this profile is 
documented in the memorandum to the docket.\194\ The agencies have 
evaluated all of the candidate road grade profiles and have prepared 
possible alternative tractor standards based on these profiles. The 
agencies request comment on this analysis, which is available in a 
memorandum to the docket.\195\
---------------------------------------------------------------------------

    \193\ See NREL Report ``EPA Road Grade profiles'' for DOE-EPA 
Interagency Agreement to Refine Drive Cycles for GHG Certification 
of Medium- and Heavy-Duty Vehicles, IA Number DW-89-92402501.
    \194\ Memorandum dated April 2015 on Possible Tractor, Trailer, 
and Vocational Vehicle Standards Derived from Alternative Road Grade 
Profiles.
    \195\ Ibid.
---------------------------------------------------------------------------

    For the proposal, the agencies developed an interim road grade 
profile for development of the proposed standards. The agencies are 
proposing the inclusion of an interim road grade profile, as shown 
below in Figure III-2, in both the 55 mph and 65 mph cycles. The grade 
profile was developed by Southwest Research Institute on a 12.5 mile 
stretch of restricted-access highway during on-road tests conducted for 
EPA's validation of the Phase 2 version of GEM.\196\ The minimum grade 
in the interim cycle is -2.1 percent and the maximum grade is 2.4 
percent. The cycle spends 30 percent of the distance in grades of +/- 
0.5 percent. Overall, the cycle spends approximately 50 percent of the 
time in relatively flat terrain with road gradients of less than 1 
percent.
---------------------------------------------------------------------------

    \196\ Southwest Research Institute. ``GEM Validation'', 
Technical Research Workshop supporting EPA and NHTSA Phase 2 
Standards for MD/HD Greenhouse Gas and Fuel Efficiency--December 10 
and 11, 2014. Can be accessed at http://www.epa.gov/otaq/climate/regs-heavy-duty.htm.
---------------------------------------------------------------------------

    The agencies believe the interim cycle has sufficient 
representativeness based on a comparison to data from the Department of 
Transportation used in the development of the light-duty Federal Test 
Procedure cycle (FTP), which found approximately 55 percent of the 
vehicle miles traveled were on road gradients of less than 1 
percent.\197\ Consequently, we expect that road grade profiles 
developed by NREL and by the agencies will not differ significantly 
from the interim profile proposed here. The agencies request data from 
fleet operators or others that have real world grade profile data.
---------------------------------------------------------------------------

    \197\ U.S. EPA. FTP Preliminary Report. May 14, 1993. Table 5-1, 
page 76. EPA-420-R-93-007.
[GRAPHIC] [TIFF OMITTED] TP13JY15.003

(c) Weight Reduction
    In Phase 1, the agencies adopted regulations that provided 
manufacturers with the ability to use GEM to measure emission reduction 
and reductions in fuel consumption resulting from use of high strength 
steel and aluminum components for weight reduction,, and to do so 
without the burden of entering the curb weight of every tractor 
produced. We treated such weight reduction in two ways in Phase 1 to 
account for the fact that combination tractor-trailers weigh-out 
approximately one-third of the time and cube-out approximately two-
thirds of the time. Therefore, one-third of the weight reduction is 
added payload in the denominator while two-thirds of the weight 
reduction is subtracted from the overall weight of the vehicle in GEM. 
See 76 FR 57153. The agencies also allowed manufacturers to petition 
for off-cycle credits for components not measured in GEM.
    NHTSA and EPA propose carrying the Phase 1 treatment of weight 
reduction into Phase 2. That is, these types of weight reduction, 
although not part of the agencies' technology packages for

[[Page 40249]]

the proposed (or alternative) standards, can still be recognized in GEM 
up to a point. In addition, the agencies propose to add additional 
thermoplastic components to the weight reduction table, as shown below 
in Table III-35. The thermoplastic component weight reduction values 
were developed in coordination with SABIC, a thermoplastic component 
supplier. Also, in Phase 2, we are proposing to recognize the potential 
weight reduction opportunities in the powertrain and drivetrain systems 
as part of the vehicle inputs into GEM. Therefore, we believe it is 
appropriate to also recognize the weight reduction associated with both 
smaller engines and 6x2 axles.\198\ We propose including the values 
listed in Table III-36 and make them available upon promulgation of the 
final Phase 2 rules (i.e., available even under Phase 1). We welcome 
comments on all aspects of weight reduction.
---------------------------------------------------------------------------

    \198\ North American Council for Freight Efficiency. 
``Confidence Findings on the Potential of 6x2 Axles.'' 2014. Page 
16.

                    Table III-35--Proposed Phase 2 Weight Reduction Technologies for Tractors
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
                               Weight reduction technology                                    Weight reduction
                                                                                             (lb per tire/wheel)
----------------------------------------------------------------------------------------------------------------
Single Wide Drive Tire with.....................  Steel Wheel............................                     84
                                                  Aluminum Wheel.........................                    139
                                                  Light Weight Aluminum Wheel............                    147
Steer Tire or Dual Wide Drive Tire with.........  High Strength Steel Wheel..............                      8
                                                  Aluminum Wheel.........................                     21
                                                  Light Weight Aluminum Wheel............                     30
----------------------------------------------------------------------------------------------------------------


 
                                                                   Aluminum      High strength    Thermoplastic
                                                                    weight        steel weight        weight
                Weight reduction technologies                     reduction        reduction        reduction
                                                                    (lb.)            (lb.)            (lb.)
----------------------------------------------------------------------------------------------------------------
Door (per door)..............................................               20                6  ...............
Roof (per vehicle)...........................................               60               18  ...............
Cab rear wall (per vehicle)..................................               49               16  ...............
Cab floor (per vehicle)......................................               56               18  ...............
Hood (per vehicle)...........................................               55               17  ...............
Hood Support Structure (per vehicle).........................               15                3  ...............
Hood and Front Fender (per vehicle)..........................  ...............  ...............               65
Day Cab Roof Fairing (per vehicle)...........................  ...............  ...............               18
Sleeper Cab Roof Fairing (per vehicle).......................               75               20               40
Aerodynamic Side Extender (per vehicle)......................  ...............  ...............               10
Fairing Support Structure (per vehicle)......................               35                6  ...............
Instrument Panel Support Structure (per vehicle).............                5                1  ...............
Brake Drums--Drive (per 4)...................................              140               11  ...............
Brake Drums--Non Drive (per 2)...............................               60                8  ...............
Frame Rails (per vehicle)....................................              440               87  ...............
Crossmember--Cab (per vehicle)...............................               15                5  ...............
Crossmember--Suspension (per vehicle)........................               25                6  ...............
Crossmember--Non Suspension ( per 3).........................               15                5  ...............
Fifth Wheel (per vehicle)....................................              100               25  ...............
Radiator Support (per vehicle)...............................               20                6  ...............
Fuel Tank Support Structure (per vehicle)....................               40               12  ...............
Steps (per vehicle)..........................................               35                6  ...............
Bumper (per vehicle).........................................               33               10  ...............
Shackles (per vehicle).......................................               10                3  ...............
Front Axle (per vehicle).....................................               60               15  ...............
Suspension Brackets, Hangers (per vehicle)...................              100               30  ...............
Transmission Case (per vehicle)..............................               50               12  ...............
Clutch Housing (per vehicle).................................               40               10  ...............
Drive Axle Hubs (per 4)......................................               80               20  ...............
Non Drive Front Hubs (per 2).................................               40                5  ...............
Driveshaft (per vehicle).....................................               20                5  ...............
Transmission/Clutch Shift Levers (per vehicle)...............               20                4  ...............
----------------------------------------------------------------------------------------------------------------


    Table III-36--Proposed Phase 2 Weight Reduction Values for Other
                               Components
------------------------------------------------------------------------
                                                      Weight reduction
            Weight reduction technology                     (lb)
------------------------------------------------------------------------
6x2 axle configuration in tractors................                   300
4x2 axle configuration in Class 8 tractors........                   300
Tractor engine with displacement less than 14.0L..              \199\300
CI Liquified Natural Gas tractor..................       \200\ \201\-600
SI Compressed Natural Gas tractor.................                  -525

[[Page 40250]]

 
CI Compressed Natural Gas tractor.................                  -900
------------------------------------------------------------------------

(d) GEM Inputs
---------------------------------------------------------------------------

    \199\ Kenworth. ``Kenworth T680 with PACCAR MX-13 Engine Lowers 
Costs for Oregon Open-Deck Carrier.'' Last viewed on December 16, 
2014 at http://www.kenworth.com/news/news-releases/2013/december/t680-cotc.aspx.
    \200\ National Energy Policy Institute. ``What Set of Conditions 
Would Make the Business Case to Convert Heavy Trucks to Natural 
Gas?--A Case Study.'' May 1, 2012. Last accessed on December 15, 
2014 at http://www.tagnaturalgasinfo.com/uploads/1/2/2/3/12232668/natural_gas_for_heavy_trucks.pdf.
    \201\ Westport presentation (2013). Last accessed on December 
15, 2014 at http://www.westport.com/file_library/files/webinar/2013-06-19_CNGandLNG.pdf.
---------------------------------------------------------------------------

    The agencies propose to continue to require the Phase 1 GEM inputs 
for tractors in Phase 2. These inputs include the following:
     Steer tire rolling resistance,
     Drive tire rolling resistance,
     Coefficient of Drag Area,
     Idle Reduction, and
     Vehicle Speed Limiter.
    As discussed above in Section II.C and III.D, there are several 
additional inputs that are proposed for Phase 2. The new GEM inputs 
proposed for Phase 2 include the following:
     Engine information including manufacturer, model, 
combustion type, fuel type, family name, and calibration identification
     Engine fuel map,
     Engine full-load torque curve,
     Engine motoring curve,
     Transmission information including manufacturer and model
     Transmission type,
     Transmission gear ratios,
     Drive axle ratio,
     Loaded tire radius for drive tires, and
     Other technology inputs.
    The agencies welcome comments on the inclusion of these proposed 
technologies into GEM in Phase 2.
(e) Vehicle Speed Limiters and Extended Idle Provisions
    The agencies received comments during the development of Phase 1 
that the Clean Air Act provisions to prevent tampering (CAA section 
203(a)(3)(A); 42 U.S.C. 7522(a)(3)(A)) of vehicle speed limiters and 
extended idle reduction technologies would prohibit their use for 
demonstrating compliance with the Phase 1 standards. In Phase 1, the 
agencies adopted provisions to allow for discounted credits for idle 
reduction technologies that allowed for override conditions and 
expiring engine shutdown systems (see 40 CFR 1037.660). Similarly, the 
agencies adopted provisions to allow for ``soft top'' speeds and 
expiring vehicle speed limiters, and we are not proposing to change 
those provisions (see 40 CFR 1037.640). However, as we develop Phase 2, 
we understand that the concerns still exist that the ability for a 
tractor manufacturer to reflect the use of a VSL in its compliance 
determination may be constrained by the demand for flexibility in the 
use of VSLs by the customers. . The agencies welcome suggestions on how 
to close the gap between the provisions that would be acceptable to the 
industry while maintaining our need to ensure that modifications do not 
violate 42 U.S.C. 7522(a)(3)(A). We request comment on potential 
approaches which would enable feedback mechanism between the vehicle 
owner/fleet that would provide the agencies the assurance that the 
benefits of the VSLs will be seen in use but which also provides the 
vehicle owner/fleet the flexibility they many need during in-use 
operation. More generally in our discussions with several trucking 
fleets and with the American Trucking Associations an interest was 
expressed by the fleets if there was a means by which they could 
participate in the emissions credit transactions which is currently 
limited to the directly regulated truck manufacturers. VSLs and 
extended idle systems were two example technologies that fleets and 
individual owners can order for a new build truck, and that from the 
fleet's perspective the truck manufacturers receive emission credits 
for. The agencies do not have a specific proposal or a position on the 
request from the American Trucking Association and its members, but we 
request comment on whether or not it is appropriate to allow owners to 
participate in the overall compliance process for the directly 
regulated parties, if such a thing is allowed under the two agencies' 
respective statutes, and what regulatory provisions would be needed to 
incorporate such an approach.
(f) Emission Control Labels
    The agencies consider it crucial that authorized compliance 
inspectors are able to identify whether a vehicle is certified, and if 
so whether it is in its certified condition. To facilitate this 
identification in Phase 1, EPA adopted labeling provisions for tractors 
that included several items. The Phase 1 tractor label must include the 
manufacturer, vehicle identifier such as the Vehicle Identification 
Number (VIN), vehicle family, regulatory subcategory, date of 
manufacture, compliance statements, and emission control system 
identifiers (see 40 CFR 1037.135). In Phase 1, the emission control 
system identifiers are limited to vehicle speed limiters, idle 
reduction technology, tire rolling resistance, some aerodynamic 
components, and other innovative and advanced technologies.
    The number of proposed emission control systems for greenhouse gas 
emissions in Phase 2 has increased significantly. For example, the 
engine, transmission, drive axle ratio, accessories, tire radius, wind 
averaged drag, predictive cruise control, and automatic tire inflation 
system are controls which can be evaluated on-cycle in Phase 2 (i.e. 
these technologies' performance can now be input to GEM), but could not 
be in Phase 1. Due to the complexity in determining greenhouse gas 
emissions as proposed in Phase 2, the agencies do not believe that we 
can unambiguously determine whether or not a vehicle is in a certified 
condition through simply comparing information that could be made 
available on an emission control label with the components installed on 
a vehicle. Therefore, EPA proposes to remove the requirement to include 
the emission control system identifiers required in 40 CFR 
1037.135(c)(6) and in Appendix III to 40 CFR part 1037 from the 
emission control labels for vehicles certified to the Phase 2 
standards. However, the agencies may finalize requirements to maintain 
some label content to facilitate a limited visual inspection of key 
vehicle parameters that can be readily observed. Such requirements may 
be very similar to the labeling requirements from the Phase 1 
rulemaking, though we would want to more carefully consider the list of 
technologies that would allow for the most effective inspection. We 
request comment on an appropriate list of candidate technologies that 
would properly balance the need to limit label content with the 
interest in providing the most useful information for inspectors to 
confirm that vehicles have been properly built. We are not proposing to 
modify the existing emission control labels for tractors certified for 
MYs 2014-2020 (Phase 1) CO2 standards.
    Under the agencies' existing authorities, manufacturers must 
provide detailed build information for a specific vehicle upon our 
request. Our expectation is that this information should be available 
to us via email or other similar electronic communication

[[Page 40251]]

on a same-day basis, or within 24 hours of a request at most. We 
request comment on any practical limitations in promptly providing this 
information. We also request comment on approaches that would minimize 
burden for manufacturers to respond to requests for vehicle build 
information and would expedite an authorized compliance inspector's 
visual inspection. For example, the agencies have started to explore 
ideas that would provide inspectors with an electronic method to 
identify vehicles and access on-line databases that would list all of 
the engine-specific and vehicle-specific emissions control system 
information. We believe that electronic and Internet technology exists 
today for using scan tools to read a bar code or radio frequency 
identification tag affixed to a vehicle that would then lead to secure 
on-line access to a database of manufacturers' detailed vehicle and 
engine build information. Our exploratory work on these ideas has 
raised questions about the level of effort that would be required to 
develop, implement and maintain an information technology system to 
provide inspectors real-time access to this information. We have also 
considered questions about privacy and data security. We request 
comment on the concept of electronic labels and database access, 
including any available information on similar systems that exist today 
and on burden estimates and approaches that could address concerns 
about privacy and data security. Based on new information that we 
receive, we may consider initiating a separate rulemaking effort to 
propose and request comment on implementing such an approach.
(g) End of Year Reports
    In the Phase 1 program, manufacturers participating in the ABT 
program provided 90 day and 270 day reports to EPA and NHTSA after the 
end of the model year. The agencies adopted two reports for the initial 
program to help manufacturers become familiar with the reporting 
process. For the HD Phase 2 program, the agencies propose to simplify 
reporting such that manufacturers would only be required to submit the 
final report 90 days after the end of the model year with the potential 
to obtain approval for a delay up to 30 days. We are accordingly 
proposing to eliminate the end of year report, which represents a 
preliminary set of ABT figures for the preceding year. We welcome 
comment on this proposed revision.
(h) Special Compliance Provisions
    In Phase 2, the agencies propose to consider the performance of the 
engine, transmission, and drivetrain in determining compliance with the 
Phase 2 tractor standards. With the inclusion of the engine's 
performance in the vehicle compliance, EPA proposes to modify the 
prohibition to introducing into U.S. commerce a tractor containing an 
engine not certified for use in tractor (see proposed 40 CFR 
1037.601(a)(1)). In Phase 2, we no longer see the need to prohibit the 
use of vocational engines in tractors because the performance of the 
engine would be appropriately reflected in GEM. We welcome comment on 
removing this prohibition.
    The agencies also propose to change the compliance process for 
manufacturers seeking to use the off-road exclusion. During the Phase 1 
program, manufacturers realized that contacting the agencies in advance 
of the model year was necessary to determine whether vehicles would 
qualify for exemption and need approved certificates of conformity. The 
agencies found that the petition process allowed at the end of the 
model year was not necessary and that an informal approval during the 
precertification period was more effective. Therefore, NHTSA is 
proposing to remove its off-road petitioning process in 49 CFR 535.8 
and EPA is proposing to add requirements for informal approvals in 40 
CFR 1037.610.
(i) Chassis Dynamometer Testing Requirement
    The agencies foresee the need to continue to track the progress of 
the Phase 2 program throughout its implementation. As discussed in 
Section II, the agencies expect to evaluate the overall performance of 
tractors with the GEM results provided by manufacturers through the end 
of year reports. However, we also need to continue to have confidence 
in our simulation tool, GEM, as the vehicle technologies continue to 
evolve. Therefore, EPA proposes that the manufacturers conduct annual 
chassis dynamometer testing of three sleeper cabs tractor and two day 
cab tractor and provide the data and the GEM result from each of these 
two tractor configurations to EPA (see 40 CFR 1037.665). We request 
comment on the costs and efficacy of this data submission requirement. 
We emphasize that this program would not be used for compliance or 
enforcement purposes.

F. Flexibility Provisions

    EPA and NHTSA are proposing two flexibility provisions specifically 
for heavy-duty tractor manufacturers in Phase 2. These are an 
averaging, banking and trading program for CO2 emissions and 
fuel consumption credits, as well as provisions for credits for off-
cycle technologies which are not included as inputs to the GEM. Credits 
generated under these provisions can only be used within the same 
averaging set which generated the credit.
    The agencies are also proposing to remove or modify several Phase 1 
interim provisions, as described below.
(1) Averaging, Banking, and Trading (ABT) Program
    Averaging, banking, and trading of emission credits have been an 
important part of many EPA mobile source programs under CAA Title II, 
and the NHTSA light-duty CAFE program. The agencies also included this 
flexibility in the HD Phase 1 program. ABT provisions are useful 
because they can help to address many potential issues of technological 
feasibility and lead-time, as well as considerations of cost. They 
provide manufacturers flexibilities that assist in the efficient 
development and implementation of new technologies and therefore enable 
new technologies to be implemented at a more aggressive pace than 
without ABT. A well-designed ABT program can also provide important 
environmental and energy security benefits by increasing the speed at 
which new technologies can be implemented. Between MYs 2013 and 2014 
all four tractor manufacturers are taking advantage of the ABT 
provisions in the Phase 1 program. NHTSA and EPA propose to carry-over 
the Phase 1 ABT provisions for tractors into Phase 2.
    The agencies propose to continue the five year credit life and 
three year deficit carry-over provisions from Phase 1 (40 CFR 
1037.740(c) and 1037.745). Please see additional discussion in Section 
I.C.1.b. Although we are not proposing any additional restrictions on 
the use of Phase 1 credits, we are requesting comment on this issue. 
Early indications suggest that positive market reception to the Phase 1 
technologies could lead to manufacturers accumulating credits surpluses 
that could be quite large at the beginning of the proposed Phase 2 
program. This appears especially likely for tractors. The agencies are 
specifically requesting comment on the likelihood of this happening, 
and whether any regulatory changes would be appropriate. For example, 
should the agencies limit the amount of credits than could be carried

[[Page 40252]]

over from Phase 1 or limit them to the first year or two of the Phase 2 
program? Also, if we determine that large surpluses are likely, how 
should that factor into our decision on the feasibility of more 
stringent standards in MY 2021?
    We welcome comments on these proposed flexibilities and are 
interested in information that may indicate doing as proposed could 
distort the heavy-duty vehicle market.
(2) Off-Cycle Technology Credits
    In Phase 1, the agencies adopted an emissions and fuel consumption 
credit generating opportunity that applied to innovative technologies 
that reduce fuel consumption and CO2 emissions. These 
technologies were required to not be in common use with heavy-duty 
vehicles before the 2010MY and not reflected in the GEM simulation tool 
(i.e., the benefits are ``off-cycle''). See 76 FR 57253. The agencies 
propose to largely continue, but redesignate the Phase 1 innovative 
technology program as part of the off-cycle program for Phase 2. In 
other words, beginning in 2021 MY all technologies that are not fully 
accounted for in the GEM simulation tool, or by compliance dynamometer 
testing could be considered off-cycle, including those technologies 
that may have been considered innovative technologies in Phase 1 of the 
program. The agencies propose to maintain the requirement that, in 
order for a manufacturer to receive credits for Phase 2, the off-cycle 
technology would still need to meet the requirement that it was not in 
common use prior to MY 2010. For additional information on the 
treatment of off-cycle technologies see Section I.C.1.c.
    The agencies are proposing a split process for handling off-cycle 
technologies in Phase 2. First, there is a set of predefined off-cycle 
technologies that are entering the market today, but could be fully-
recognized in our proposed HD Phase 2 certification procedures. 
Examples of such technologies include predictive cruise control, 6x2 
axles, axle lubricants, automated tire inflation systems, and air 
conditioning efficiency improvements. For these technologies, the 
agencies propose to define the effectiveness value of these 
technologies similar to the approach taken in the MY2017-2025 light-
duty rule (see 77 FR 62832-62840 (October 15, 2012)). These default 
effectiveness values could be used as valid inputs to Phase 2 GEM. The 
proposed effectiveness value of each technology is discussed above in 
Section III.D.2.
    The agencies also recognize that there are emerging technologies 
today that are being developed, but would not be accounted for in the 
GEM inputs, therefore would be considered off-cycle. These technologies 
could include systems such as efficient steering systems, cooling fan 
optimization, and further tractor-trailer integration. These off-cycle 
technologies could include known, commercialized technologies if they 
are not yet widely utilized in a particular heavy-duty sector 
subcategory. Any credits for these technologies would need to be based 
on real-world fuel consumption and GHG reductions that can be measured 
with verifiable test methods using representative driving conditions 
typical of the engine or vehicle application.
    The agencies propose that the approval for Phase 1 innovative 
technology credits (approved prior to 2021 MY) would be carried into 
the Phase 2 program on a limited basis for those technologies where the 
benefit is not accounted for in the Phase 2 test procedure. Therefore, 
the manufacturers would not be required to request new approval for any 
innovative credits carried into the off-cycle program, but would have 
to demonstrate the new cycle does not account for these improvements 
beginning in the 2021 MY. The agencies believe this is appropriate 
because technologies, such as those related to the transmission or 
driveline, may no longer be ``off-cycle'' because of the addition of 
these technologies into the Phase 2 version of GEM. The agencies also 
seek comments on whether off-cycle technologies in the Phase 2 program 
should be limited by infrequent common use and by what model years, if 
any. We also seek comments on an appropriate penetration rate for a 
technology not to be considered in common use.
    As in Phase 1, the agencies are proposing to continue to provide 
two paths for approval of the test procedure to measure the 
CO2 emissions and fuel consumption reductions of an off-
cycle technology used in the HD tractor. See proposed 40 CFR 1037.610 
and 49 CFR 535.7. The first path would not require a public approval 
process of the test method. A manufacturer could use ``pre-approved'' 
test methods for HD vehicles including the A-to-B chassis testing, 
powerpack testing or on-road testing. A manufacturer may also use any 
developed test procedure that has known quantifiable benefits. A test 
plan detailing the testing methodology would be required to be approved 
prior to collecting any test data. The agencies are also proposing to 
continue the second path, which includes a public approval process of 
any testing method that could have questionable benefits (i.e., an 
unknown usage rate for a technology). Furthermore, the agencies are 
proposing to modify their provisions to clarify what documentation must 
be submitted for approval, which would align them with provisions in 40 
CFR 86.1869-12. NHTSA and EPA are also proposing to prohibit credits 
from technologies addressed by any of NHTSA's crash avoidance safety 
rulemakings (i.e., congestion management systems). See 77 FR 62733 
(discussing similar issues in the context of the light-duty fuel 
economy and greenhouse gas reduction standards). We welcome 
recommendations on how to improve or streamline the off-cycle 
technology approval process.
(3) Post Useful Life Modifications
    Under 40 CFR part 1037, it is generally prohibited for any person 
to remove or render inoperative any emission control device installed 
to comply with the requirements of part 1037. However, in 40 CFR 
1037.655 EPA clarifies that certain vehicle modifications are allowed 
after a vehicle reaches the end of its regulatory useful life. This 
section applies for all vehicles subject to 40 CFR part 1037 and would 
thus apply for trailers regulated in Phase 2. EPA is proposing to 
continue this provision and requests comment on it.
    This section states (as examples) that it is generally allowable to 
remove tractor roof fairings after the end of the vehicle's useful life 
if the vehicle will no longer be used primarily to pull box trailers, 
or to remove other fairings if the vehicle will no longer be used 
significantly on highways with vehicle speed of 55 miles per hour or 
higher. More generally, this section clarifies that owners may modify a 
vehicle for the purpose of reducing emissions, provided they have a 
reasonable technical basis for knowing that such modification will not 
increase emissions of any other pollutant. This essentially requires 
the owner to have information that would lead an engineer or other 
person familiar with engine and vehicle design and function to 
reasonably believe that the modifications will not increase emissions 
of any regulated pollutant. Thus, this provision does not provide a 
blanket allowance for modifications after the useful life.
    This section also makes clear that no person may ever disable a 
vehicle speed limiter prior to its expiration point, or remove 
aerodynamic fairings from tractors that are used primarily to pull box 
trailers on highways. It is also clear that this allowance does not 
apply with

[[Page 40253]]

respect to engine modifications or recalibrations.
    This section does not apply with respect to modifications that 
occur within the useful life period, other than to note that many such 
modifications to the vehicle during the useful life and to the engine 
at any time are presumed to violate 42 U.S.C. 7522(a)(3)(A). EPA notes, 
however, that this is merely a presumption, and would not prohibit 
modifications during the useful life where the owner clearly has a 
reasonable technical basis for knowing that the modifications would not 
cause the vehicle to exceed any applicable standard.
(4) Other Interim Provisions
    In HD Phase 1, EPA adopted provisions to delay the onboard 
diagnostics (OBD) requirements for heavy-duty hybrid powertrains (see 
40 CFR 86.010-18(q)). This provision delayed full OBD requirements for 
hybrids until 2016 and 2017 model years. In discussion with 
manufacturers during the development of Phase 2, the agencies have 
learned that meeting the on-board diagnostic requirements for criteria 
pollutant engine certification continues to be a potential impediment 
to adoption of hybrid systems. See Section XIV.A.1 for a discussion of 
regulatory changes proposed to reduce the non-GHG certification burden 
for engines paired with hybrid powertrain systems.
(5) Phase 1 Flexibilities Not Proposed for Phase 2
    The Phase 1 advanced technology credits were adopted to promote the 
implementation of advanced technologies, such as hybrid powertrains, 
Rankine cycle engines, all-electric vehicles, and fuel cell vehicles 
(see 40 CFR 1037.150(i)). As the agencies stated in the Phase 1 final 
rule, the Phase 1 standards were not premised on the use of advanced 
technologies but we expected these advanced technologies to be an 
important part of the Phase 2 rulemaking (76 FR 57133, September 15, 
2011). The proposed HD Phase 2 heavy-duty engine and tractor standards 
are premised on the use of Rankine-cycle engines, therefore the 
agencies believe it is no longer appropriate to provide extra credit 
for this technology. While the agencies have not premised the proposed 
HD Phase 2 tractor standards on hybrid powertrains, fuel cells, or 
electric vehicles, we also foresee some limited use of these 
technologies in 2021 and beyond. Therefore, we propose to not provide 
advanced technology credits in Phase 2 for any technology, but we 
welcome comments on the need for such incentive.
    Also in Phase 1, the agencies adopted early credits to create 
incentives for manufacturers to introduce more efficient engines and 
vehicles earlier than they otherwise would have planned to do (see 40 
CFR 1037.150(a)). The agencies are not proposing to extend this 
flexibility to Phase 2 because the ABT program from Phase 1 will be 
available to manufacturers in 2020 model year and this would displace 
the need for early credits.

IV. Trailers

    As mentioned in Section III, trailers pulled by Class 7 and 8 
tractors (together considered ``tractor-trailers'') account for 
approximately two-thirds of the heavy-duty sector's total 
CO2 emissions and fuel consumption. Because neither trailers 
nor the tractors that pull them are useful by themselves, it is the 
combination of the tractor and the trailer that forms the useful 
vehicle. Although trailers do not directly generate exhaust emissions 
or consume fuels (except for the refrigeration units on refrigerated 
trailers), their designs and operation nevertheless contribute 
substantially to the CO2 emissions and diesel fuel 
consumption of the tractors pulling them. See also Section I.E (1) and 
(2) above.
    The agencies are proposing standards for trailers specifically 
designed to be drawn by Class 7 and 8 tractors when coupled to the 
tractor's fifth wheel. The agencies are not proposing standards for 
trailers designed to be drawn by vehicles other than tractors, and 
those that are coupled to vehicles with pintle hooks or hitches instead 
of a fifth wheel. These proposed standards are expressed as 
CO2 and fuel consumption standards, and would apply to each 
trailer with respect to the emissions and fuel consumption that would 
be expected for a specific standard type of tractor pulling such a 
trailer. Note that this approach is discussed in more detail later. 
Nevertheless, EPA and NHTSA believe it is appropriate to establish 
standards for trailers separately from tractors because they are 
separately manufactured by distinct companies; the agencies are not 
aware of any manufacturers that currently assemble both the finished 
tractor and the trailer.

A. Summary of Trailer Consideration in Phase 1

    In the Phase 1 program, the agencies did not regulate trailers, but 
discussed how we might do so in the future (see 76 FR 57362). We chose 
not to regulate trailers at that time, primarily because of the lack of 
a proposed test procedure, as well as the technical and policy issues 
at that time. The agencies also noted the large number of small 
businesses in this industry, the possibility that regulations would 
substantially impact these small businesses, and the agencies' 
consequent obligations under the Small Business Regulatory Enforcement 
Fairness Act.\202\ However, the agencies did indicate the potential 
CO2 and fuel consumption benefits of including trailers in 
the program and we committed to consider establishing standards for 
trailers in future rulemakings.
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    \202\ The Regulatory Flexibility Act (RFA), as amended by the 
Small Business Regulatory Enforcement Fairness Act (SBREFA), 
requires agencies to account for economic impacts of all rules that 
may have a significant impact on a substantial number of small 
businesses and in addition contains provisions specially applicable 
to EPA requiring a multi-agency pre-proposal process involving 
outreach and consultation with representatives of potentially 
affected small businesses. See http://www.epa.gov/rfa/ for more 
information. Note that for this Phase 2 proposal, EPA has completed 
a Small Business Advocacy Review panel process that included small 
trailer manufacturers, as discussed in XIV.C below.
---------------------------------------------------------------------------

    In the Phase 1 proposal, the agencies solicited general comments on 
controlling CO2 emissions and fuel consumption through 
future trailer regulations (see 75 FR 74345-74351). Although we neither 
proposed nor finalized trailer regulations at that time, the agencies 
have considered those comments in developing this proposal. This notice 
proposes the first EPA regulations covering trailer manufacturers for 
CO2 emissions (or any other emissions), and the first fuel 
consumption regulations by NHTSA for these manufacturers. The agencies 
intend for this program to be a unified national program so that when a 
trailer model complies with EPA's standards it will also comply with 
NHTSA's standards.

B. The Trailer Industry

(1) Industry Characterization
    The trailer industry encompasses a wide variety of trailer 
applications and designs. Among these are box trailers (dry vans and 
refrigerated vans of all sizes) and ``non-box'' trailers, including 
platform (sometimes called ``flatbed''), tanker, container chassis, 
bulk, dump, grain, and many specialized types of trailers, such as car 
carriers, pole trailers, and logging trailers. Most trailers are 
designed for predominant use on paved streets, roads, and highways 
(called ``highway trailers'' for purposes of this proposed rule). A 
relatively small number of trailers are designed for dedicated use in 
logging and mining operations or for use in

[[Page 40254]]

applications that we expect would involve little or no time on paved 
roadways. A more detailed description of the characteristics that 
distinguish these trailers is included in Section IV.C.(5).
    The trailer manufacturing industry is very competitive, and 
manufacturers are highly responsive to their customers' diverse 
demands. The wide range of trailer designs and features reflects the 
broad variety of customer needs, chief among them typically being the 
ability to maximize the amount of freight the trailer can transport. 
Other design goals reflect the numerous, more specialized customer 
needs.
    Box trailers are the most common type of trailer and are made in 
many different lengths, generally ranging from 28 feet to 53 feet. 
While all have a rectangular shape, they can vary widely in basic 
construction design (internal volume and weight), materials (steel, 
fiberglass composites, aluminum, and wood) and the number and 
configuration of axles (usually two axles closely spaced, but number 
and spacing of axles can be greater). Box trailer designs may also 
include additional features, such as one or more side doors, out-
swinging or roll-up rear doors, side or rear lift gates, and numerous 
types of undercarriage accessories.
    Non-box trailers are uniquely designed to transport a specific type 
of freight. Platform trailers carry cargo that may not be easily 
contained within or loaded and unloaded into a box trailer, such as 
large, nonuniform equipment or machine components. Tank trailers are 
often pressure-tight enclosures designed to carry liquids, gases or 
bulk, dry solids and semi-solids. There are also a number of other 
specialized trailers such as grain, dump, automobile hauler, livestock 
trailers, construction and heavy-hauling trailers.
    Chapter 1 of the Draft RIA includes a more thorough 
characterization of the trailer industry. The agencies have considered 
the variety of trailer designs and applications in developing the 
proposed CO2 emissions and fuel consumption standards for 
trailers.
(2) Historical Context for Proposed Trailer Provisions
(a) SmartWay Program
    EPA's voluntary SmartWay Transport Partnership program encourages 
businesses to take actions that reduce fuel consumption and 
CO2 emissions while cutting costs. See Section I.A.2.f 
above. SmartWay staff work with the shipping, logistics, and carrier 
communities to identify low carbon strategies and technologies across 
their transportation supply chains. It is a voluntary, fleet-targeted 
program that provides an objective ranking of a fleet's freight 
efficiency relative to its competitors. SmartWay Partners commit to 
adopting fuel-saving practices and technologies relative to a baseline 
year as well as tracking their progress.
    EPA's SmartWay program has accelerated the availability and market 
penetration of advanced, fuel efficient technologies and operational 
practices. In conjunction with the SmartWay Partners Program, EPA 
established a testing, verification, and designation program, the 
SmartWay Technology Program, to help freight companies identify the 
equipment, technologies, and strategies that save fuel and lower 
emissions. SmartWay verifies the performance of aerodynamic equipment 
and low rolling resistance tires and maintains a list of verified 
technologies on its Web site. The trailer aerodynamic technologies 
verified are grouped in bins that represent one percent, four percent, 
or five percent fuel savings relative to a typical long-haul tractor-
trailer at 65-mph cruise conditions. Historically, use of verified 
aerodynamic devices totaling at least five percent fuel savings, along 
with verified tires, qualifies a 53-foot dry van trailer for the 
``SmartWay Trailer'' designation. In 2014, EPA expanded the program to 
qualify trailers as ``SmartWay Elite'' if they use verified tires and 
aerodynamic equipment providing nine percent or greater fuel savings. 
The 2014 updates also expanded the SmartWay-designated trailer 
eligibility to include 53-foot refrigerated van trailers in addition to 
53-foot dry van trailers.
    The SmartWay Technology Program continues to improve the technical 
quality of data that EPA and stakeholders need for verification. EPA 
bases its SmartWay verifications on common industry test methods using 
SmartWay-specified testing protocols. Historically, SmartWay's 
aerodynamic equipment verification was performed using the SAE J1321 
test procedure, which measures fuel consumption as the test vehicle 
drives laps around a test track. Under SmartWay's 2014 updates, EPA 
expanded its trailer designation and equipment verification programs to 
allow additional testing options. The updates included a new, more 
stringent 2014 track test protocol based on SAE's 2012 update to its 
SAE J1321 test method,\203\ as well as protocols for wind tunnel, 
coastdown, and possibly computational fluid dynamics (CFD) approaches. 
These new protocols are based on stakeholder input, the latest industry 
standards (i.e., 2012 versions of the SAE fuel consumption and wind 
tunnel test \204\ methods), EPA's own testing and research, and lessons 
learned from years of implementing technology verification programs. 
Wind tunnel, coastdown, and CFD testing produce values for aerodynamic 
drag improvements in terms of coefficient of drag (CD), 
which is then related to projected fuel savings using a mathematical 
curve.\205\
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    \203\ SAE International, Fuel Consumption Test Procedure--Type 
II. SAE Standard J1321. Revised 2012-02-06. Available at: http://standards.sae.org/j1321_201202/.
    \204\ SAE International. Wind Tunnel Test Procedure for Trucks 
and Buses. SAE Standard J1252. Revised 2012-07-16. Available at: 
http://standards.sae.org/j1252_201207/.
    \205\ McCallen, R., et al. Progress in Reducing Aerodynamic Drag 
for Higher Efficiency of Heavy Duty Trucks (Class 7-8). SAE 
Technical Paper. 1999-01-2238.
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    SmartWay verifies tires based on test data submitted by tire 
manufacturers demonstrating the coefficient of rolling resistance 
(CRR) of their tires using either the SAE J1269 or ISO 28580 
test methods. These verified tires have rolling resistance targets for 
each axle position on the tractor-trailer. SmartWay-verified trailer 
tires achieve a CRR of 5.1 kg/metric ton or less on the 
ISO28580 test method. An operator who replaces the trailer tires with 
SmartWay-verified tires can expect fuel consumption savings of one 
percent or more at a 65-mph cruise. Operators who apply SmartWay-
verified tires on both the trailer and tractor can achieve three 
percent fuel consumption savings at 65-mph.
    Over the last decade, SmartWay partners have demonstrated 
measureable fuel consumption benefits by adding aerodynamic features 
and low rolling resistance tires to their 53-foot dry van trailers. To 
date, SmartWay has verified over 70 technologies, including nine 
packages from five manufacturers that have received the Elite 
designation. The SmartWay Transport program has worked with over 3,000 
partners, the majority of which are trucking fleets, and broadly 
throughout the supply-chain industry, since 2004. These relationships, 
combined with the Technology Program's extensive involvement in the HD 
vehicle technology industry, have provided EPA with significant 
experience in freight fuel efficiency. Furthermore, the more than 10-
year duration of the voluntary SmartWay Transport Partnership has 
resulted in significant fleet and manufacturer experience with 
innovating and deploying technologies

[[Page 40255]]

that reduce CO2 emissions and fuel consumption.
(b) California Tractor-Trailer Greenhouse Gas Regulation
    The state of California passed the Global Warming Solutions Act of 
2006 (Assembly Bill 32, or AB32), enacting the state's 2020 greenhouse 
gas emissions reduction goal into law. Pursuant to this Act, the 
California Air Resource Board (CARB) was required to begin developing 
early actions to reduce GHG emissions. As a part of a larger effort to 
comply with AB32, the California Air Resource Board issued a regulation 
entitled ``Heavy-Duty Greenhouse Gas Emission Reduction Regulation'' in 
December 2008.
    This regulation reduces GHG emissions by requiring improvement in 
the efficiency of heavy-duty tractors and 53 foot or longer dry and 
refrigerated box trailers that operate in California.\206\ The program 
is being phased in between 2010 and 2020. Small fleets have been 
allowed special compliance opportunities to phase in the retrofits of 
their existing trailer fleets through 2017. The regulation requires 
affected trailer fleet owners to either use SmartWay-verified trailers 
or to retrofit trailers with SmartWay-verified technologies. The 
efficiency improvements are achieved through the use of aerodynamic 
equipment and low rolling resistance tires on both the tractor and 
trailer. EPA has granted a waiver for this California program.\207\
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    \206\ Recently, in December 2013, ARB adopted regulations that 
establish its own parallel Phase 1 program with standards consistent 
with the EPA Phase 1 tractor standards. On December 5, 2014 
California's Office of Administrative Law approved ARB's adoption of 
the Phase 1 standards, with an effective date of December 5, 2014.
    \207\ See EPA's waiver of CARB's heavy-duty tractor-trailer 
greenhouse gas regulation applicable to new 2011 through 2013 model 
year Class 8 tractors equipped with integrated sleeper berths 
(sleeper-cab tractors) and 2011 and subsequent model year dry-can 
and refrigerated-van trailers that are pulled by such tractors on 
California highways at 79 FR 46256 (August 7, 2014).
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(c) NHTSA Safety-Related Regulations for Trailers and Tires
    NHTSA regulates new trailer safety through regulations. Table IV-1 
lists the current regulations in place related to trailers. Trailer 
manufacturers will continue to be required to meet current safety 
regulations for the trailers they produce. We welcome any comments on 
additional regulations that are not included and particularly those 
that may be incompatible with the regulations outlined in this 
proposal.
    FMVSS Nos. 223 and 224 \208\ require installation of rear guard 
protection on trailers. The definition of rear extremity of the trailer 
in 223 limits installation of rear fairings to a specified zone behind 
the trailer. The agencies request comment on any issues associated with 
installing potential boat tails or other rear aerodynamic fairings that 
would be more effective than current designs, given the current 
definition of trailer rear extremity in FMVSS 223.
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    \208\ 49 CFR 571.223, 224.

 Table IV--1 Current NHTSA Statutes and Regulations Related to Trailers
------------------------------------------------------------------------
               Reference                              Title
------------------------------------------------------------------------
49 CFR 565.............................  Vehicle Identification Number
                                          (VIN) Requirements.
49 CFR 566.............................  Manufacturer Identification.
49 CFR 567.............................  Certification.
49 CFR 568.............................  Vehicles Manufactured in Two or
                                          More Stages.
49 CFR 569.............................  Regrooved Tires.
49 CFR 571.............................  Federal Motor Vehicle Safety
                                          Standards.
49 CFR 573.............................  Defect and Noncompliance
                                          Responsibility and Reports.
49 CFR 574.............................  Tire Identification and
                                          Recordkeeping.
49 CFR 575.............................  Consumer Information.
49 CFR 576.............................  Record Retention.
------------------------------------------------------------------------

(d) Additional DOT Regulations Related to Trailers
    In addition to NHTSA's regulations, DOT's Federal Highway 
Administration (FHWA) regulates the weight and dimensions of motor 
vehicles on the National Network.\209\ FHWA's regulations limit states 
from setting truck size and weight limits beyond certain ranges for 
vehicles used on the National Network. Specifically, vehicle weight and 
truck tractor-semitrailer length and width are limited by FHWA.\210\ 
EPA and NHTSA do not anticipate any conflicts between FHWA's 
regulations and those proposed in this rulemaking.
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    \209\ 23 CFR 658.9.
    \210\ 23 CFR part 658.
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(3) Agencies' Outreach in Developing This Proposal
    In developing this proposed rule, EPA and NHTSA staff met and 
consulted with a wide range of organizations that have an interest in 
trailer regulations. Staff from both agencies met representatives of 
the Truck Trailer Manufacturers Association, the National Trailer 
Dealers Association, and the American Trucking Association, including 
their Fuel Efficiency Advisory Committee and their Technology and 
Maintenance Council. We also met with and visited the facilities of 
several individual trailer manufacturers, trailer aerodynamic device 
manufacturing companies, and trailer tire manufacturers, as well as 
visited an aerodynamic wind tunnel test facility and two independent 
tire testing facilities. The agencies consulted with representatives 
from California Air Resources Board, the International Council on Clean 
Transportation, the North American Council for Freight Efficiency, and 
several environmental NGOs.
    In addition to these informal meetings, and as noted above, EPA 
also conducted several outreach meetings with representatives from 
small business trailer manufacturers as required under section 609(b) 
of the Regulatory Flexibility Act (RFA) and amended by the Small 
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA). EPA 
convened a Small Business Advocacy Review (SBAR) Panel, and additional 
information regarding the findings and recommendations of the Panel are 
available in Section XIV below and in the Panel's final report.\211\ 
EPA worked with NHTSA to propose flexibilities in response to EPA's 
SBAR Panel (as outlined in Section IV. F(6)(f) with more detail 
provided in Chapter 12 of the draft RIA). We welcome comments from all 
entities and the public to all aspects of this proposal.
---------------------------------------------------------------------------

    \211\ Final Report of the Small Business Advocacy Review Panel 
on EPA's Planned Proposed Rule: Greenhouse Gas Emissions and Fuel 
Efficiency Standards for Medium- and Heavy-Duty Engines and 
Vehicles: Phase 2, January 15, 2015.
---------------------------------------------------------------------------

C. Proposed Phase 2 Trailer Standards

    This proposed rule proposes, for the first time, a set of 
CO2 emission and fuel consumption standards for 
manufacturers of new trailers that would phase in over a period of nine 
years and continue to reduce CO2 emissions and fuel 
consumption in the years to follow. The proposed standards are 
expressed as overall CO2 emissions and fuel consumption 
performance standards considering the trailer as an integral part of 
the tractor-trailer vehicle.
    The agencies are proposing trailer standards that we believe well 
implement our respective statutory obligations. The agencies believe 
that a proposed set of standards with similar stringencies, but less 
lead-time (referred to as ``Alternative 4'' and discussed in more 
detail later) has the potential to be the maximum feasible alternative 
within the meaning of section 32902 (k) of EISA, and appropriate under 
EPA's CAA authority (sections 202 (a)(1) and (2)). However, based on 
the evidence

[[Page 40256]]

currently before us, EPA and NHTSA have outstanding questions regarding 
relative risks and benefits of Alternative 4 due to the timeframe 
envisioned by that alternative. The proposed alternative (referred to 
as ``Alternative 3'' and discussed in more detail later) is generally 
designed to achieve the levels of fuel consumption and GHG reduction 
that Alternative 4 would achieve, but with several years of additional 
lead-time. Put another way, the Alternative 3 standards would result in 
the same stringency as the Alternative 4 standards, but several years 
later, meaning that manufacturers could, in theory apply new technology 
at a more gradual pace and with greater flexibility. Additional lead-
time will also provide for a more gradual implementation of full 
compliance program, which could be especially helpful for this newly-
regulated trailer industry. It is possible that the agencies could 
adopt, in full or in part, stringencies from Alternative 4 in the final 
rule. The agencies seek comment on the lead-time and market penetration 
in these alternatives.
    The agencies are not proposing standards for CO2 
emissions and fuel consumption from the transport refrigeration units 
(TRUs) used on refrigerated box trailers. Additionally, EPA is not 
proposing standards for hydrofluorocarbon (HFC) emissions from TRUs. 
See Section IV.C.(4)
    It is worth noting that the proposed standards for box trailers are 
based in part on the expectation that the proposed program would allow 
emissions averaging. However, as discussed in Section IV.F. below, 
given the specific structure and competitive nature of the trailer 
industry, we request comment on the advantages and disadvantages of 
implementing the proposed standards without an averaging program. 
Commenters addressing the stringency of the proposed standards are 
encouraged to address stringency in the context of compliance programs 
with and without averaging.
(1) Trailer Designs Covered by This Proposed Rule
    As described previously, the trailer industry produces many 
different trailer designs for many different applications. The agencies 
are proposing standards for a majority of these trailers. Note that 
these proposed regulations apply to trailers designed for being drawn 
by a tractor when coupled to the tractor's fifth wheel. As described in 
detail in Section IV.C below, the agencies are proposing standards that 
would phase in between MY 2018 and 2027; the NHTSA standards would be 
voluntary until MY 2021. The proposed standards would apply to most 
types of trailers. For most box trailers, these standards would be 
based on the use of various technologies to improve aerodynamic 
performance, and on improved tire efficiency through low rolling 
resistance tires and use of automatic tire inflation (ATI) systems. As 
discussed below, the agencies have identified some trailers with 
characteristics that limit the aerodynamics that can be applied, and 
are proposing reduced the stringencies for those trailer types. As 
described in Sections IV.D.(1)(d) and (2)(d) below, although 
manufacturers can reduce trailer weight to reduce fuel costs by 
reducing trailer weight, these standards are not predicated on weight 
reduction for the industry.
    The most comprehensive set of proposed requirements would apply to 
long box trailers, which include refrigerated and non-refrigerated 
(dry) vans. Long box trailers are the largest trailer category and are 
typically paired with high roof cab tractors that have high annual 
vehicle miles traveled (VMT) and high average speeds, and therefore 
offer the greatest potential for CO2 and fuel consumption 
reductions. Many of the aerodynamic and tire technologies considered 
for long box trailers in this proposal are similar to those used in 
EPA's SmartWay program and required by California's Heavy-Duty 
Greenhouse Gas Emission Reduction Regulation. Many manufacturers and 
operators of box trailers have experience with these CO2- 
and fuel consumption-reducing technologies. In addition to SmartWay 
partners and those fleets affected by the California regulation, many 
operators also seek such technologies in response to high fuel prices 
and the prospect of improved fuel efficiency. As a result, more data 
about the performance of these technologies exist for long box trailers 
than for other trailer types. Short box vans do not have the benefit of 
programs such as SmartWay to provide an incentive for development of 
and a reliable evaluation and promotion of CO2- and fuel 
consumption-reducing technologies for their trailers. In addition, 
short box trailers are more frequently used in short-haul and urban 
operations, which may limit the potential effectiveness of these 
technologies. As such, EPA is proposing less stringent requirements for 
manufacturers of short box trailers.
    Some trailer designs include features that can affect the 
practicality or the effectiveness of devices that manufacturers may 
consider to lower their CO2 emissions and fuel consumption. 
We are proposing to recognize box trailers that are restricted from 
using aerodynamic devices in one location on the trailer as ``partial-
aero'' box trailers.\212\ The proposed standards for these trailers are 
based on the proposed standards for full-aero box-trailers, but would 
be less stringent than when the program is fully phased in.
---------------------------------------------------------------------------

    \212\ Examples of types of work-performing components, 
equipment, or designs that the agencies might consider as warranting 
recognition as partial-aero or non-aero trailers include side or end 
lift gates, belly boxes, pull-out platforms or steps for side door 
access, and drop-deck designs. See 40 CFR 1037.107 and 49 CFR 
535.5(e).
---------------------------------------------------------------------------

    We propose that box trailers that have work-performing devices in 
two locations such that they inhibit the use of all practical 
aerodynamic devices be considered ``non-aero'' box trailers in this 
proposal. The proposed standards for non-aero box trailers are 
predicated on the use of tire technologies--lower rolling resistance 
tires and ATI. We are proposing similar standards for non-box trailers 
(including applications such as dump trailers and agricultural trailers 
that are designed to be used both on and off the highway).
    We are proposing to completely exclude several types of trailers 
from this trailer program. These excluded trailers would include those 
designed for dedicated in-field operations related to logging and 
mining. In addition, we are proposing to exclude heavy-haul trailers 
and trailers the primary function of which is performed while they are 
stationary. For all of these excluded trailers, manufacturers would not 
have any regulatory requirements under this program, and would not be 
subject to the proposed trailer compliance requirements. We seek 
comment on the appropriateness of excluding these types of trailers 
from the proposed trailer program and whether other trailer designs 
should be excluded. Section IV. C. (5) discusses these trailer types we 
propose to exclude and the physical characteristics that would define 
these trailers.
    In summary, the agencies are proposing separate standards for ten 
trailer subcategories:

--Long box (longer than 50 feet \213\) dry vans
---------------------------------------------------------------------------

    \213\ Most long trailers are 53 feet in length; we are proposing 
a cut-point of 50 feet to avoid an unintended incentive for an OEM 
to slightly shorten a trailer design in order to avoid the new 
regulatory requirements.
---------------------------------------------------------------------------

--Long box (longer than 50 feet) refrigerated vans
--Short box (50 feet and shorter) dry vans
--Short box (50 feet and shorter) refrigerated vans
--Partial-aero long box dry vans
--Partial-aero long box refrigerated vans
--Partial-aero short box dry vans

[[Page 40257]]

--Partial-aero short box refrigerated vans
--Non-aero box vans (all lengths of dry and refrigerated vans)
--Non-box trailers (tanker, platform, container chassis, and all other 
types of highway trailers that are not box trailers)

    As discussed in the next section, partial-aero box trailers would 
have the same standards as their corresponding full-aero trailers in 
the early phase-in years, and would have separate, less stringent 
standards as the program is fully implemented. Section IV. C. (5) 
introduces these proposed partial-aero trailer standards and Section 
IV. D. describes the technologies that could be applied to meet these 
proposed standards.
(2) Proposed Fuel Consumption and CO2 Standards
    As described in previously, it is the combination of the tractor 
and the trailer that form the useful vehicle, and trailer designs 
substantially affect the CO2 emissions and diesel fuel 
consumption of the tractors pulling them. Note that although the 
agencies are proposing new CO2 and fuel consumption 
standards for trailers separately from tractors, we set the numerical 
level of the trailer standards (see Section IV.D below) in relation to 
``standard'' reference tractors in recognition of their 
interrelatedness. In other words, the regulatory standards refer to the 
simulated emissions and fuel consumption of a standard tractor pulling 
the trailer being certified.
    The agencies project that these proposed standards, when fully 
implemented in MY (model year) 2027, would achieve fuel consumption and 
CO2 emissions reductions of three to eight percent, 
depending on trailer subcategory. These projected reductions assume a 
degree of technology adoption into the future absent the proposed 
program and are evaluated on a weighted drive cycle (see Section IV. D. 
(3) . We expect that the MY 2027 standards would be met with high-
performing aerodynamic and tire technologies largely available in the 
marketplace today. With a lead-time of more than 10 years, the agencies 
believe that both trailer construction and bolt-on CO2- and 
fuel consumption-reducing technologies will advance well beyond the 
performance of their current counterparts that exist today. A 
description of technologies that the agencies considered for this 
proposal is provided in Section IV. D.
    The agencies designed this proposed trailer program to ensure a 
gradual progression of both stringency and compliance requirements in 
order to limit the impact on this newly-regulated industry. The 
agencies are proposing progressively more stringent standards in three-
year stages leading up to the MY 2027.\214\ The agencies are proposing 
several options to reduce compliance burden (see Section IV. F.) in the 
early years as the industry gains experience with the program. EPA is 
proposing to initiate its program in 2018 with modest standards for 
long box dry and refrigerated vans that can be met with common 
SmartWay-verified aerodynamic and tire technologies. In this early 
stage, we expect that manufacturers of the other trailer subcategories 
would meet those standards by using tire technologies only. Standards 
that we propose for the next stages, which we propose to begin in MY 
2021, MY 2024, and MY 2027, would gradually increase in stringency for 
each subcategory, including the introduction of standards for shorter 
box vans that we expect would be met by applying both aerodynamic and 
tire technologies. NHTSA's regulations would be voluntary until MY 2021 
as described in Section IV. C. (3).
---------------------------------------------------------------------------

    \214\ These stages are consistent with NHTSA's stability 
requirements under EISA.
---------------------------------------------------------------------------

    Table IV-2 below presents the CO2 and fuel consumption 
phase-in standards, beginning in MY 2018 that the agencies are 
proposing for trailers. The standards are expressed in grams of 
CO2 per ton-mile and gallons of fuel per 1,000 ton-miles to 
reflect the load-carrying capacity of the trailers. Partial-aero 
trailers would be subject to the same standards as their corresponding 
``full aero'' trailers for MY 2018 through MY 2026. In MY 2027 and the 
years to follow, partial-aero trailers would continue to meet the 
standards for MY 2024.
    The agencies are not proposing CO2 or fuel consumption 
standards predicated on aerodynamic improvements for non-box trailers 
or non-aero box vans at any stage of this proposed program. Instead, we 
are proposing design standards that would require manufacturers of 
these trailers to adopt specific tire technologies and thus to comply 
without aerodynamic devices. We believe that this approach would 
significantly limit the compliance burden for these manufacturers and 
request comment on this provision.\215\
---------------------------------------------------------------------------

    \215\ The agencies are not proposing provisions to allow 
averaging for non-box trailers, non-aero box trailers, or partial-
aero box trailers, and this reduced flexibility would likely have 
the effect of requiring compliant tire technologies to be used.

                Table IV-2--Proposed Trailer CO2 and Fuel Consumption Standards for Box Trailers
----------------------------------------------------------------------------------------------------------------
                                   Subcategory                Dry van                    Refrigerated van
          Model year           ---------------------------------------------------------------------------------
                                     Length            Long            Short           Long            Short
----------------------------------------------------------------------------------------------------------------
2018-2020.....................  EPA Standard....              83             144              84             147
                                (CO2 Grams per
                                 Ton-Mile).
                                Voluntary NHTSA           8.1532         14.1454          8.2515         14.4401
                                 Standard.
                                (Gallons per
                                 1,000 Ton-Mile).
2021-2023.....................  EPA Standard....              81             142              82             146
                                (CO2 Grams per
                                 Ton-Mile).
                                NHTSA Standard..          7.9568         13.9489          8.0550         14.3418
                                (Gallons per
                                 1,000 Ton-Mile).
2024-2026.....................  EPA Standard....              79             141              81             144
                                (CO2 Grams per
                                 Ton-Mile).
                                NHTSA Standard..          7.7603         13.8507          7.9568         14.1454
                                (Gallons per
                                 1,000 Ton-Mile).
2027 +........................  EPA Standard....              77             140              80             144
                                (CO2 Grams per
                                 Ton-Mile).
                                NHTSA Standard..          7.5639         13.7525          7.8585         14.1454
                                (Gallons per
                                 1,000 Ton-Mile).
----------------------------------------------------------------------------------------------------------------


[[Page 40258]]

    Differences in the numerical values of these standards among 
trailer subcategories are due to differences in the tractor-trailer 
characteristics, as well as differences in the default payloads, in the 
vehicle simulation model we used to develop the proposed standards (as 
described in Section IV. D. (3) (a) below). Lower numerical values in 
Table IV-2 do not necessarily indicate more stringent standards. For 
instance, the proposed standards for dry and refrigerated vans of the 
same length have the same stringency through MY 2026, but the standards 
recognize differences in trailer weight and aerodynamic performance due 
to the TRU on refrigerated vans. Trailers of the same type but 
different length differ in weight as well as in the number of axles 
(and tires), tractor type, payload and aerodynamic performance. Section 
IV. D. and Chapter 2.10 of the draft RIA provide more details on the 
characteristics of the tractor-trailer vehicles, with various 
technologies, that are the basis for these standards.
    In developing the proposed standards for trailers, the agencies 
evaluated the current level of CO2 emissions and fuel 
consumption, the types and availability of technologies that could be 
applied to reduce CO2 and fuel consumption, and the current 
adoption rates of these technologies. Additionally, we considered the 
necessary lead-time and associated costs to the industry to meet these 
standards, as well as the fuel savings to the consumer and magnitude of 
CO2 and fuel savings that we project would be achieved as a 
result of these proposed standards. As discussed in more detail later 
in this preamble and in Chapter 2.10 of the draft RIA, the analyses of 
trailer aerodynamic and tire technologies that the agencies have 
conducted appear to show that these proposed standards would be the 
maximum feasible and appropriate in the lead-time provided under each 
agency's respective statutory authorities. We ask that any comments 
related to stringency include data whenever possible indicating the 
potential effectiveness and cost of adding such devices to these 
vehicles.
    The agencies request comment on all aspects of these proposed 
standards, including trailers to be covered and the proposed 50-foot 
demarcation between ``long'' and ``short'' box vans, the proposed 
phase-in schedule, and the stringency of the standards in relation to 
their cost, CO2 and fuel consumption reductions, and on the 
proposed compliance provisions, as discussed in Section IV. F.
    In addition to these proposed trailer standards, the agencies 
considered standards both less stringent and more stringent than the 
proposed standards. We specifically request comment on a set of 
accelerated standards that we considered, as presented in Section IV. 
E. This set of standards is predicated on performance and penetration 
rates of the same technologies as the proposed standards, but would 
reach full implementation three years sooner.
(3) Lead-Time Considerations
    As mentioned earlier, although the agencies did not include 
standards for trailers in Phase 1, box trailer manufacturers have been 
gaining experience with CO2- and fuel consumption-reducing 
technologies over the past several years, and the agencies expect that 
trend to continue, due in part to EPA's SmartWay program and 
California's Tractor-Trailer Greenhouse Gas Regulation. Most 
manufacturers of long box trailers have some experience installing 
these aerodynamic and tire technologies for customers. This experience 
impacts how much lead-time is necessary from a technological 
perspective. EPA is proposing CO2 emission standards for 
long box trailers for MY 2018 that represent stringency levels similar 
to those used for SmartWay verification and required for the California 
regulation, and thus could be met by adopting off-the-shelf aerodynamic 
and tire technologies available today. The NHTSA program from 2018 
through 2020 would be voluntary.
    Manufacturers of trailers other than 53-foot box vans do not have 
the benefit of programs such as SmartWay to provide a reliable 
evaluation and promotion of these technologies for their trailers and 
therefore have less experience with these technologies. As such, EPA is 
proposing less stringent requirements for manufacturers of other 
highway trailer subcategories beginning in MY 2018. We expect these 
manufacturers of short box trailers would adopt some aerodynamic and 
tire technologies, and manufacturers of other trailers would adopt tire 
technologies only, as a means of achieving the proposed standards. Some 
manufacturers of trailers other than long boxes may not yet have direct 
experience with these technologies, but the technologies they would 
need are fairly simple and can be incorporated into trailer production 
lines without significant process changes. Also, the NHTSA program for 
these trailers would be voluntary until MY 2021.
    The agencies believe that the burdens of installing and marketing 
these technologies would not be limiting factors in determining 
necessary lead-time for manufacturers of these trailers. Instead, we 
expect that the proposed first-time compliance and, in some cases, 
performance testing requirements, would be the more challenging 
obstacles for this newly regulated industry. For these reasons, we are 
proposing that these standards phase in over a period of nine years, 
with flexibilities that would minimize the compliance and testing 
burdens in the early years of the proposed program (see Section IV. 
F.).
    As mentioned previously, EPA is proposing modest standards and 
several compliance options that would allow it to begin its program for 
MY 2018. However, EISA requires four model years of lead-time for fuel 
consumption standards, regardless of the stringency level or 
availability of flexibilities. Therefore, NHTSA's proposed fuel 
consumption requirements would not become mandatory until MY 2021. 
Prior to MY 2021, trailer manufacturers could voluntarily participate 
in NHTSA's program, noting that once they made such a choice, they 
would need to stay in the program for all succeeding model years.\216\
---------------------------------------------------------------------------

    \216\ NHTSA adopted a similar voluntary approach in the first 
years of Phase 1 (see 76 FR 57106).
---------------------------------------------------------------------------

    The agencies believe that the expected period of seven years or 
more between the issuing of the final rules and full implementation of 
the program would provide sufficient lead-time for all affected trailer 
manufacturers to adopt CO2- and fuel consumption-reducing 
technologies or design trailers to meet the proposed standards.
(4) Non-CO2 GHG Emissions from Trailers
    In addition to the impact of trailer design on the CO2 
emissions of tractor-trailer vehicles, the agencies recognize that 
refrigerated trailers can also be a source of emissions of HFCs. 
Specifically, HFC refrigerants that are used in transport refrigeration 
units (TRUs) have the potential to leak into the atmosphere. We do not 
currently believe that HFC leakage is likely to become a major problem 
in the near future, and we are not proposing provisions addressing 
refrigerant leakage of trailer-related HFCs in this proposed 
rulemaking. TRUs differ from the other source categories where EPA has 
adopted (or proposed) to apply HFC leakage requirements (i.e., air 
conditioning). We believe trailer owners have a strong incentive to 
limit refrigerant leakage in order to maintain the operability of the 
trailer's refrigeration unit and avoid financial liability for damage 
to perishable freight due to a failure to maintain the agreed-

[[Page 40259]]

upon temperature and humidity conditions. In addition, refrigerated van 
units represent a relatively small fraction of new trailers. 
Nevertheless, we request comment on this issue, including any data on 
typical TRU charge capacity, the frequency of HFC refrigerant leakage 
from these units across the fleet, the magnitude of unaddressed leakage 
from individual units, and how potential EPA regulations might address 
this leakage issue.
(5) Exclusions and Less-Stringent Standards
    All trailers built before January 1, 2018 are excluded from the 
Phase 2 trailer program, and from 40 CFR part 1037 and 49 CFR part 535 
in general (see 40 CFR 1037.5(g) and 49 CFR 535.3(e)). Furthermore, the 
proposed regulations do not apply to trailers designed to be drawn by 
vehicles other than tractors, and those that are coupled to vehicles 
with pintle hooks or hitches instead of a fifth wheel. As stated 
previously, we are proposing that non-box trailers that are designed 
for dedicated use with in-field operations related to logging and 
mining be completely excluded from this Phase 2 trailer program. The 
agencies believe that the operational capabilities of trailers designed 
for these purposes could be compromised by the use of aerodynamic 
devices or tires with lower rolling resistance. Additionally, the 
agencies are proposing to exclude trailers designed for heavy-haul 
applications and those that are not intended for highway use, as 
follows:

--Trailers shorter than 35 feet in length with three axles, and all 
trailers with four or more axles (including any lift axles)
--Trailers designed to operate at low speeds such that they are 
unsuitable for normal highway operation
--Trailers designed to perform their primary function while stationary
--Trailers intended for temporary or permanent residence, office space, 
or other work space, such as campers, mobile homes, and carnival 
trailers
--Trailers designed to transport livestock
--Incomplete trailers that are sold to a secondary manufacturer for 
modification to serve a purpose other than transporting freight, such 
as for offices or storage \217\
---------------------------------------------------------------------------

    \217\ Secondary manufacturers who purchase incomplete trailers 
and complete their construction to serve as trailers are subject to 
the requirements of 40 CFR 1037.620.

    Where the criteria for exclusion identified above may be unclear 
for specific trailer models, manufacturers would be encouraged to ask 
the agencies to make a determination before production begins. The 
agencies seek comments on these and any other trailer characteristics 
that might make the trailers incompatible with highway use or would 
restrict their typical operating speeds.
    Because the agencies are proposing that these trailers be excluded 
from the program, we are not proposing to require manufacturers to 
report to the agencies about these excluded trailers. We seek comments 
on whether, in lieu of the exclusion of trailers from the program, the 
agencies should instead exempt these trailers from the standards, but 
still require reporting to the agencies in order to verify that a 
manufacturer qualifies for an exemption. In that case, exempt trailers 
would have some regulatory requirements (e.g., reporting); again, 
excluded trailers would have no regulatory requirements under this 
proposal. All other trailers would remain covered by the proposed 
standards.
    As described earlier, the proposed program is based on the 
expectation that manufacturers would be able to apply aerodynamic 
devices and tire technologies to the vast majority of box trailers, and 
these standards would be relatively stringent. We propose to categorize 
trailers with functional components or work-performing equipment, and 
trailers with certain design elements, that could partially interfere 
with the installation or the effectiveness of some aerodynamic 
technologies, as ``partial-aero'' box trailers. For example, some 
trailer equipment by their placement or their need for operator access 
might not be compatible with current designs of trailer skirts, but a 
boat tail could be effective on that trailer in the early years of the 
program. Similarly, a rear lift gate or roll-up rear door might not be 
compatible with a current boat tail design, but skirts could be 
effective. The proposed requirements for these trailers would the same 
as their full-aero counterparts until MY 2027, at which time they would 
continue to be subject to the MY 2024 standards. See 40 CFR 1037.107.
    For trailers for which no aerodynamic devices are practical, the 
agencies are proposing design standards requiring LRR tires and ATI 
systems. Trailers for which neither skirt/under-body devices nor rear-
end devices would be likely to be feasible fall into two categories: 
non-box trailers and non-aero box trailers. We believe that there is 
limited availability of aerodynamic technologies for non-box trailers 
(for example, platform (flatbed) trailers, tank trailers, and container 
chassis trailers). Also, for container chassis trailers, operational 
considerations, such as stacking of the chassis trailers, impede 
introduction of aerodynamic technologies. In addition, manufacturers of 
these trailer types have little or no experience with aerodynamic 
technologies designed for their products. Non-aero box trailers, 
defined as those with equipment or design features that would preclude 
both skirt/under-body and rear-end aerodynamic technologies (e.g., a 
trailer with both a pull-out platform for side access and a rear lift 
gate), would be subject to the same tire-only design standards as would 
non-box trailers, based exclusively on the performance of tire and ATI 
technologies.\218\
---------------------------------------------------------------------------

    \218\ The agencies are not aware of work-performing equipment 
that would prevent the use of gap-reducing trailer devices on dry 
vans of any length; thus dry vans with side and rear equipment could 
qualify as ``non-aero'' trailers, even if the manufacturer could 
install a gap-reducing device.
---------------------------------------------------------------------------

    We recognize that the shortest short box vans (i.e., less than 35 
feet) are often pulled in tandem. Since these trailers make up the 
majority of trailers in the short box van subcategories, we are not 
proposing standards for short box dry and refrigerated vans based on 
the use of rear devices. Thus, work-performing features on the rear of 
the trailer (e.g., lift gates) would not impact a trailer's ability to 
meet the full-aero short-box trailer standards. As a result, we are 
proposing that all short box vans only be categorized as partial-aero 
vans if they have work-performing side features (e.g., belly boxes). We 
expect that partial-aero short dry van trailers would be able to adopt 
front-side devices that would achieve the reduced standards. 
Furthermore, some short box trailers that are not operated in tandem, 
such as 40- or 48-foot trailers, could also be able to adopt rear-side 
devices and achieve even greater reductions.
    Refrigerated short box vans are a special case in that they have 
TRUs that limit the ability to apply aerodynamic technologies to the 
front side of the trailers. Because of this, we are proposing to 
classify the shortest refrigerated box vans (shorter than 35 feet) as 
non-aero trailers if they are designed with work-performing side 
features. Since these trailers may be pulled in tandem and since they 
cannot adopt front-side aerodynamic devices, we propose that they meet 
standards predicated on tire technologies only. Short box refrigerated 
trailers 35 feet and longer would only qualify for non-aero standards 
if they have work-

[[Page 40260]]

performing devices on both the side and rear of the trailer. See 40 CFR 
1037.107.
    We request comment on these proposed provisions for excluding some 
trailers from the program, including speed restrictions and physical 
characteristics that would generally make them incompatible for highway 
use. We also request comment on the proposed approach of applying less-
stringent standards to non-box, non-aero box, and partial-aero box 
trailers.
(6) In-Use Standards
    Consistent with Section 202(a)(1) of the CAA, EPA is proposing that 
the emissions standards apply for the useful life of the trailers. 
NHTSA also proposes to adopt EPA's useful life requirements for 
trailers to ensure manufacturers consider in the design process the 
need for fuel efficiency standards to apply for the same duration and 
mileage as EPA standards. Aerodynamic devices available today, 
including trailer skirts, rear fairings, under-body devices, and gap-
reducing fairings, are designed to maintain their physical integrity 
for the life of the trailer. In the absence of failures like 
detachment, breakage, or misalignment, we expect that the aerodynamic 
performance of the devices will not degrade appreciably over time and 
that the projected CO2 and fuel consumption reductions will 
continue for the life of the vehicle with no special maintenance 
requirements. Because of this, EPA does not see a benefit to 
establishing separate standards that would apply in-use for trailers. 
EPA and NHTSA are proposing a regulatory useful life value for trailers 
of 10 years, and thus the certification standards would apply in-use 
for that period of time.\219\ See Section IV. F. (5) (a) for a 
discussion of other factors related to trailer useful life.
---------------------------------------------------------------------------

    \219\ EPA may perform in-use testing of any vehicle subject to 
the standards of this part, including trailers. For example, we may 
test trailers to verify drag areas or other GEM inputs.
---------------------------------------------------------------------------

D. Feasibility of the Proposed Trailer Standards

    As discussed below, the agencies' initial determination, subject to 
consideration of public comment, is that the standards presented in the 
Section IV.C.2, are the maximum feasible and appropriate under the 
agencies' respective authorities, considering lead time, cost, and 
other factors. We summarize our analyses in this section, and describe 
them in more detail in the Draft RIA (Chapter 2.10).
    Our analysis of the feasibility of the proposed CO2 and 
fuel consumption standards is based on technology cost and 
effectiveness values collected from several sources. Our assessment of 
the proposed trailer program is based on information from:

--Southwest Research Institute evaluation of heavy-duty vehicle fuel 
efficiency and costs for NHTSA,\220\
---------------------------------------------------------------------------

    \220\ Reinhart, T.E. (June 2015). Commercial Medium- and Heavy-
Duty Truck Fuel Efficiency Technology Study--Report #1. (Report No. 
DOT HS 812 146). Washington, DC: National Highway Traffic Safety 
Administration.
---------------------------------------------------------------------------

--2010 National Academy of Sciences report of Technologies and 
Approaches to Reducing the Fuel Consumption of Medium- and Heavy-Duty 
Vehicles,\221\
---------------------------------------------------------------------------

    \221\ Committee to Assess Fuel Economy Technologies for Medium- 
and Heavy-Duty Vehicles; National Research Council; Transportation 
Research Board (2010). Technologies and Approaches to Reducing the 
Fuel Consumption of Medium- and Heavy-Duty Vehicles. (``The NAS 
Report'') Washington, DC, The National Academies Press. Available 
electronically from the National Academy Press Web site at http://www.nap.edu/catalog.php?record_id=12845.
---------------------------------------------------------------------------

--TIAX's assessment of technologies to support the NAS panel 
report,\222\
---------------------------------------------------------------------------

    \222\ TIAX, LLC. ``Assessment of Fuel Economy Technologies for 
Medium- and Heavy-Duty Vehicles,'' Final Report to National Academy 
of Sciences, November 19, 2009.
---------------------------------------------------------------------------

--The analysis conducted by the Northeast States Center for a Clean Air 
Future, International Council on Clean Transportation, Southwest 
Research Institute and TIAX for reducing fuel consumption of heavy-duty 
long haul combination tractors (the NESCCAF/ICCT study),\223\
---------------------------------------------------------------------------

    \223\ NESCCAF, ICCT, Southwest Research Institute, and TIAX. 
Reducing Heavy-Duty Long Haul Combination Truck Fuel Consumption and 
CO2 Emissions. October 2009.
---------------------------------------------------------------------------

--The technology cost analysis conducted by ICF for EPA,\224\ and
---------------------------------------------------------------------------

    \224\ ICF International. ``Investigation of Costs for Strategies 
to Reduce Greenhouse Gas Emissions for Heavy-Duty On-Road 
Vehicles.'' July 2010. Docket Number EPA-HQ-OAR-2010-0162-0283.
---------------------------------------------------------------------------

--Testing conducted by EPA.

    As an initial step in our analysis, we identified the extent to 
which fuel consumption- and CO2-reducing technologies are in 
use today.
    The technologies include those that reduce aerodynamic drag at the 
front, back, and underside of trailers, tires with lower rolling 
resistance, tire inflation technologies, and weight reduction through 
component substitution. It should be noted that the agencies need not 
and did not attempt to predict the exact future pathway of the 
industry's response to the new standards, but rather demonstrated one 
example of how compliance could reasonably occur, taking into account 
cost of the standards (including costs of compliance testing and 
certification), and needed lead time. We are proposing that full-aero 
box trailer manufacturers have additional flexibility in meeting the 
standards through averaging. The less complex standards proposed for 
partial- and non-aero box and non-box trailers would still provide a 
degree of technology choices that would meet their standards.
    For our feasibility analysis, we identified a set of technologies 
to represent the range of those likely to be used in the time frame of 
the rule. We then combined these technologies into packages of 
increasing effectiveness in reducing CO2 and fuel 
consumption and projected reasonable rates at which the evaluated 
technologies and packages could be adopted across the trailer industry. 
More details regarding our analysis can be found in Chapter 2.10.4.1 of 
the draft RIA.
    The agencies developed the proposed CO2 and fuel 
consumption standards for each stage of the program by combining the 
projected effectiveness of trailer technologies and the projected 
adoption rates for each trailer type. We evaluated these standards with 
respect to the cost of these technologies, the emission reductions and 
fuel consumption improvements achieved, and the lead-time needed to 
deploy the technology at a given adoption rate.
    Unlike the other sectors covered by this Phase 2 rulemaking, 
trailer manufacturers do not have experience certifying under the Phase 
1 program. Moreover, a large fraction of the trailer industry is 
composed of small businesses and very few of the largest trailer 
manufacturers have the same resources available as manufacturers in the 
other heavy-duty sectors. The standards have been developed with this 
in mind, and we are confident the proposed standards can be achieved by 
manufacturers who lack prior experience implementing such standards.
(1) Available Technologies
    Trailer manufacturers can design a trailer to reduce fuel 
consumption and CO2 emissions by addressing the trailer's 
aerodynamic drag, tire rolling resistance and weight. In this section 
we outline the general trailer technologies that the agencies 
considered in evaluating the feasibility of the proposed standards.
(a) Aerodynamic Drag Reduction
    Historically, the primary goal when designing the shape of box 
trailers has been to maximize usable internal cargo volume, while 
complying with regulatory size limits and minimizing construction 
costs. This led to standard box trailers being rectangular. This basic 
shape creates significant aerodynamic

[[Page 40261]]

drag and makes box trailers strong candidates for aerodynamic 
improvements. Current bolt-on aerodynamic technologies for box trailers 
are designed to create a smooth transition of airflow from the tractor, 
around the trailer, and beyond the trailer.
    Table IV-3 lists general aerodynamic technologies that the EPA 
SmartWay program has evaluated for use on box trailers and a 
description of their intended impact. Several versions of each of these 
technologies are commercially available and have seen increased 
adoption over the past decade. Performance of these devices varies 
based on their design, their location and orientation on the trailer, 
and the vehicle speed. More information regarding the agencies' initial 
assessment of these devices, including incremental costs is discussed 
in Chapter 2.10 of the draft RIA.

          Table IV-3--Aerodynamic Technologies for Box Trailers
------------------------------------------------------------------------
                                        Example       Intended impact on
       Location on trailer           technologies        aerodynamics
------------------------------------------------------------------------
Front...........................  Front fairings and  Reduce cross-flow
                                   gap-reducing        through gap and
                                   fairings.           smoothly
                                                       transition
                                                       airflow from
                                                       tractor to the
                                                       trailer.
Rear............................  Rear fairings,      Reduce pressure
                                   boat tails and      drag induced by
                                   flow diffusers.     the trailer wake.
Underside.......................  Side fairings and   Manage flow of air
                                   skirts, and         under the trailer
                                   underbody devices.  to reduce
                                                       turbulence,
                                                       eddies and wake.
------------------------------------------------------------------------

    As mentioned previously, SmartWay-verified technologies are 
evaluated on 53-foot dry vans. However, the CO2- and fuel 
consumption-reducing potential of some aerodynamic technologies 
demonstrated on 53-foot dry vans can be translated to refrigerated vans 
and box trailers in lengths different than 53 feet and some fleets have 
opted to add trailer skirts to their refrigerated vans and 28-foot 
trailers (often called ``pups''). In addition, some side skirts have 
been adapted for non-box trailers (e.g., tankers, platforms, and 
container chassis), and have shown potential for large reductions in 
drag. At this time, however, non-box trailer aerodynamic devices are 
not widely available, with many still at the prototype stage. The 
agencies encourage commenters to provide more information and data 
related to the effectiveness of technologies applied to trailers other 
than 53-foot dry and refrigerated vans.
    ``Boat tail'' devices, applied to the rear of a trailer, are 
typically designed to collapse flat as the trailer rear doors are 
opened. If the tail structure can remain in the collapsed configuration 
when the doors are closed, the benefit of the device is lost. The 
agencies request comment on whether we should require that trailer 
manufacturers using such devices for compliance with the proposed 
standards only use designs that automatically deploy when the vehicle 
is in motion.
    The agencies are aware that physical characteristics of some box 
trailers influence the technologies that can be applied. For instance, 
the TRUs on refrigerated vans are located at the front of the trailer, 
which prohibits the use of current gap-reducers. Similarly, drop deck 
dry vans have lowered floors between the landing gear and the trailer 
axles that limit the ability to use side skirts. The agencies 
considered the availability and limitations of aerodynamic technologies 
for each trailer type evaluated in our feasibility analysis of the 
proposed and alternative standards.
(b) Tire Rolling Resistance
    On a typical Class 8 long-haul tractor-trailer, over 40 percent of 
the total energy loss from tires is attributed to rolling resistance 
from the trailer tires.\225\ Trailer tire rolling resistance values 
collected by the agencies for Phase 1 indicate that the average 
coefficient of rolling resistance (CRR) for new trailer 
tires was 6.0 kg/ton. This value was applied for the standard trailer 
used for tractor compliance in the Phase 1 tractor program. For Phase 
2, the agencies consider all trailer tires with CRR values 
below 6.0 kg/ton to be ``lower rolling resistance'' (LRR) tires. For 
reference, a trailer tire that qualifies as a SmartWay-verified tire 
must meet a CRR value of 5.1 kg/ton, a 15 percent 
CRR reduction from the trailer tire identified in Phase 1. 
Our research of rolling resistance indicates an additional 
CRR reduction of 15 percent or more from the SmartWay 
verification threshold is possible with tires that are available in the 
commercial market today.
---------------------------------------------------------------------------

    \225\ ``Tires & Truck Fuel Economy: A New Perspective'', The 
Tire Topic Magazine, Special Edition Four, 2008, Bridgestone 
Firestone, North American Tire, LLC. Available online: http://www.trucktires.com/bridgestone/us_eng/brochures/pdf/08-Tires_and_Truck_Fuel_Economy.pdf.
---------------------------------------------------------------------------

    For this proposal, the agencies are proposing to use the same 
rolling resistance baseline value of 6.0 kg/ton for all trailer 
subcategories. We request comment on the appropriateness of 6.0 kg/ton 
as the proposed CRR threshold for all regulated trailers. 
Specifically, the agencies would like more information on current 
adoption rates of and CRR values for models of LRR tires 
currently in use on short box trailers and the various non-box 
trailers.
    Similar to the case of tractor tires, LRR tires are available as 
either dual or as single wide-based tires for trailers. Single wide-
based tires achieve CRR values that are similar to their 
dual counterparts, but have an added benefit of weight reduction, which 
can be an attractive option for trailers that frequently maximize cargo 
weight. See Section IV.D.1.d below.
(c) Tire Pressure Systems
    The inflation pressure of tires also impacts the rolling 
resistance. Tractor-trailers operating with all tires under-inflated by 
10 psi have been shown to increase fuel consumed by up to 1 
percent.\226\ Tires can gradually lose pressure from small punctures, 
leaky valves or simply diffusion through the tire casing. Changes in 
ambient temperature can also have an effect on tire pressure. Trailers 
that remain unused for long periods of time between hauls may 
experience any of these conditions. A 2003 FMCSA report found that 
nearly 1 in 5 trailers had at least 1 tire under-inflated by 20 psi or 
more. If drivers or fleets are not diligent about checking and 
attending to under-inflated tires, the trailer may have much higher 
rolling resistance and much higher CO2 emissions and fuel 
consumption.
---------------------------------------------------------------------------

    \226\ ``Tire Pressure Systems--Confidence Report''. North 
American Council for Freight Efficiency. 2013. Available online: 
http://nacfe.org/wp-content/uploads/2014/01/TPS-Detailed-Confidence-Report1.pdf.
---------------------------------------------------------------------------

    Tire pressure monitoring (TPM) and automatic tire inflation (ATI) 
systems are designed to address under-inflated tires. Both systems 
alert drivers if a tire's pressure drops below its set point. TPM 
systems are simpler and merely monitor tire pressure. Thus, they 
require user-interaction to re inflate to the appropriate pressure. 
Today's ATI systems, on the other hand, typically

[[Page 40262]]

take advantage of trailers' air brake systems to supply air back into 
the tires (continuously or on demand) until a selected pressure is 
achieved. In the event of a slow leak, ATI systems have the added 
benefit of maintaining enough pressure to allow the driver to get to a 
safe stopping area. The agencies believe TPM systems cannot 
sufficiently guarantee the proper inflation of tires due to the 
inherent user-interaction required. Therefore, ATI systems are the only 
pressure systems the agencies are proposing to recognize in Phase 2.
    Benefits of ATI systems in individual trailers vary depending on 
the base level of maintenance already performed by the driver or fleet, 
as well as the number of miles the trailer travels. Trailers that are 
well maintained or that travel fewer miles will experience less 
benefits from ATI systems compared to trailers that often drive with 
poorly inflated tires or log many miles. The agencies believe ATI 
systems can provide a CO2 and fuel consumption benefit to 
most trailers. With ATI use, trailers that have lower annual vehicle 
miles traveled (VMT) due to long periods between uses would be less 
susceptible to low tire pressures when they resume activity. Trailers 
with high annual VMT would experience the fuel savings associated with 
consistent tire pressures. Automatic tire inflation systems could 
provide a CO2 and fuel consumption savings of 0.5-2.0 
percent, depending on the degree of under-inflation in the trailer 
system. See Section IV.D.3.d below for discussion of our estimates of 
these factors, as well as estimates of the degree of adoption of ATI 
systems prior to and at various points in the phase-in of the proposed 
program.
    The use of ATI systems can result in cost savings beyond reducing 
fuel costs. For example, drivers and fleets that diligently maintain 
their tires would spend less time and money to inspect each tire. A 
2011 FMCSA estimated under-inflation accounts for one service call per 
year and increases tire procurement costs 10 to 13 percent. The study 
found that total operating costs can increase by $600 to $800 per year 
due to under-inflation.\227\
---------------------------------------------------------------------------

    \227\ TMC Future Truck Committee Presentation ``FMCSA Tire 
Pressure Monitoring Field Operational Test Results,'' February 8, 
2011.
---------------------------------------------------------------------------

(d) Weight Reduction
    Reduction in trailer tare (i.e., empty) weight can lead to fuel 
efficiency reductions in two ways. For applications where payload is 
not limited by weight restrictions, the overall weight of the tractor 
and trailer would be reduced and would lead to improved fuel 
efficiency. For applications where payload is limited by weight 
restrictions, the lower trailer weight would allow additional payload 
to be transported during the truck's trip, so emissions and fuel 
consumption on a ton-mile basis would decrease. There are weight 
reduction opportunities for trailers in both the structural components 
and in the wheels/tires. Material substitution (e.g., replacing steel 
with aluminum or lighter-weight composites) is feasible for components 
such as roof bows, side and corner posts, cross members, floor joists, 
floors, and van sidewalls. Similar material substitution is feasible 
for wheels (e.g., substituting aluminum for steel). Weight can also be 
reduced through the use of single wide-based tires replacing two dual 
tires.
    Lower weight is a desired trailer attribute for many customers, and 
most trailer manufacturers offer options that reduce weight to some 
degree. Some of these manufacturers, especially box van makers, market 
trailers with lower-weight major components, such as light-weight 
composite van sidewalls or aluminum floors, especially to customers 
that expect to frequently reach regulatory weight limits (i.e., ``weigh 
out'') and are willing to pay a premium for the ability to increase 
cargo weight without exceeding overall vehicle weight. Alternatively, 
manufacturers that primarily design trailers for customers that do not 
have weight limit concerns (i.e., their payloads frequently fill the 
available trailer cargo space before the weight limit is reached, or 
``cube out''), or for customers that have smaller budgets, may continue 
to design trailers based on traditional, heavier materials, such as 
wood and steel.
    There is no clear ``baseline'' for current trailer weight against 
which lower-weight designs could be compared for regulatory purposes. 
For this reason, the agencies do not believe it would be appropriate or 
fair across the industry to apply overall weight reductions toward 
compliance. However, the agencies do believe it would be appropriate to 
allow a manufacturer to account for weight reductions that involve 
substituting very specific, traditionally heavier components with 
lower-weight options that are not currently widely adopted in the 
industry. We discuss how we apply weight reduction in developing the 
standards in Section IV. D. (2)(d) below.
(2) Technological Basis of the Standards
    The analysis below presents one possible set of technology designs 
by which trailer manufacturers could reasonably achieve the goals of 
the program on average. However, in practice, trailer manufacturers 
could choose different technologies, versions of technologies, and 
combinations of technologies that meet the business needs of their 
customers while complying with this proposed program.
    Much of our analysis is performed for box trailers, which have the 
most stringent proposed standards. As mentioned previously, we have 
separate standards for short and long box vans, and a trailer length of 
50 feet is proposed as the cut-point to distinguish the two length 
categories. For the purpose of this analysis, long trailers are 
represented by 53-foot vans and short trailers are represented by 
single, 28-foot (``pup'') vans. These trailer lengths make up the 
largest fraction of the vans in the two categories. The agencies 
recognize that many 28-foot short vans are operated in tandem. However, 
these trailers are sold individually, and require a ``dolly'', often 
sold by a separate manufacturer, to connect the trailers for tandem 
operation.
    In addition, the other trailer types considered short vans in this 
proposal (e.g., 40-foot and 48-foot) typically operate as single 
trailers. To minimize complexity, we are proposing that 28-foot 
trailers represent all short refrigerated and dry vans for both 
compliance and for this feasibility analysis. This means that 
manufacturers would not need to perform tests (or report device 
manufacturers' test data) of the performance of devices for each 
trailer length in the short van category. Although this approach would 
provide a conservative estimate of actual CO2 emissions and 
fuel consumption reductions for the short van category, the agencies 
believe that the need to avoid an overly complex compliance program 
justifies this approach. We request comment on this approach to 
evaluating short box trailers.
(a) Aerodynamic Packages
    In order to evaluate performance and cost of the aerodynamic 
technologies discussed in the previous section, the agencies identified 
``packages'' of individual or combined technologies that are being sold 
today on box trailers. The agencies also identified distinct 
performance levels (i.e., bins) for these technologies based on EPA's 
aerodynamic testing. The agencies recognize that there are other 
technology options that have similar performance. We chose the 
technologies presented here based on their current adoption rates and 
effectiveness in reducing CO2 and fuel consumption.

[[Page 40263]]

    Bin I represents a base trailer with no aerodynamic technologies 
added. There is no cost associated with this bin. Bin II achieves small 
reductions in CO2 and fuel consumption. This bin includes a 
gap reducing fairing added to a long dry van or a skirt added to a solo 
short dry van.\228\ Bin III includes devices that would achieve 
SmartWay's verification threshold of four percent at cruise speeds. 
Some basic skirts and boat tails would achieve these levels of 
reductions for long box trailers. A gap reducer and a basic skirt on a 
short dry van would meet this level of performance. Bin IV technologies 
are more effective, single aerodynamic devices for long box trailers, 
including advanced skirts or boat tails, that achieve larger reductions 
in drag than the technologies in Bin III. The combination of an 
advanced skirt and gap reducer on a short dry van are also expected to 
achieve this bin.
---------------------------------------------------------------------------

    \228\ The agencies recognize that many 28-foot pup trailers are 
often operated in tandem. However, we are regulating and evaluating 
short dry vans as solo trailers since they are sold individually and 
the short box regulatory subcategories also include trailer sizes 
not often operated in tandem (e.g., 40-foot and 48-foot trailers).
---------------------------------------------------------------------------

    Bin V levels of performance were not observed in EPA's aerodynamic 
testing for short box trailers. It is possible that a gap reducer, 
skirt, and boat tail could achieve this performance, but boat tails are 
not feasible for 28-foot trailers operated in tandem unless the trailer 
is located in the rear position. For this analysis, the agencies only 
evaluated solo pup trailers and, therefore, did not evaluate any 
technologies for short box trailers beyond Bin IV. For this proposed 
rulemaking, we believe a Bin V level of performance can be achieved for 
long box trailers by either highly effective single devices or by 
applying a combination of basic boat tails and skirts. We do not 
currently have data for a single aerodynamic device that fits this bin 
and we evaluated it as a combination of a basic tail and skirt. Bin VI 
combines advanced skirts and boat tail technologies on long box 
trailers. This bin is expected to include many technologies that 
qualify for SmartWay's ``Elite'' designation.
    Bin VII represents an optimized system of technologies that work 
together to synergistically address each of the main areas of drag and 
achieves aerodynamic improvements greater than SmartWay's ``Elite'' 
designation. We are representing Bin VII with a gap reducer, and 
advanced tail and skirt. Bin VIII is designed to represent aerodynamic 
technologies that may become available in the future, including 
aerodynamic devices yet to be designed or approaches that would 
incorporate changes to the construction of trailer bodies. We have not 
analyzed this final bin in terms of effectiveness or cost, but are 
including it to account for future advancements in trailer 
aerodynamics.
    For this proposal, aerodynamic performance is evaluated using a 
vehicle's aerodynamic drag area, CDA. EPA collected 
aerodynamic test data for several tractor-trailer configurations, 
including 53-foot dry vans and 28-foot dry van trailers with many of 
these technology packages. The agencies developed bins, somewhat 
similar to the aerodynamic bins in the Phase 1 and proposed Phase 2 
tractor programs, based on results from our test program. However, 
unlike the tractor program, we grouped the technologies by changes in 
CDA (or ``delta CDA'') rather than by absolute 
values. In other words, each bin would comprise aerodynamic 
technologies that provide similar improvements in drag. This delta 
CDA classification methodology, which measures improvement 
in performance relative to a baseline, is similar to the SmartWay 
technology verification program with which most trailer manufacturers 
are familiar.
    Table IV-4 illustrates the bin structure that the agencies are 
proposing as the basis for compliance. The table shows example 
technology packages that might be included in each bin based on EPA's 
testing of 53-foot dry vans and solo 28-foot dry vans. The agencies 
believe these bins apply to other box trailers (refrigerated vans and 
lengths other than 28 and 53 feet), which will be described in more 
detail in Section IV.D.3.b. These bins cover a wide enough range of 
delta CDAs to account for the uncertainty seen in EPA's 
aerodynamic testing program due to procedure variability, the use of 
different test methods, or different models of tractors, trailers and 
devices. A more detailed description of the development of these bins 
can be found in the draft RIA, Chapter 2.10. We welcome comments and 
additional data that may support or suggest changes to these bins.

                     Table IV-4--Technology Bins Used To Evaluate Trailer Benefits and Costs
----------------------------------------------------------------------------------------------------------------
                                                                                Example technologies
                Bin                    Delta CdA     Average delta ---------------------------------------------
                                                          CDA          53-foot dry van        28-foot dry van
----------------------------------------------------------------------------------------------------------------
Bin I.............................          < 0.09             0.0  No Aero Devices......  No Aero Devices.
Bin II............................       0.10-0.19             0.1  Gap Reducer..........  Skirt.
Bin III...........................       0.20-0.39             0.3  Basic Skirt or Basic   Skirt + Gap Reducer.
                                                                     Tail.
Bin IV............................       0.40-0.59             0.5  Advanced Skirt or      Adv. Skirt + Gap
                                                                     Tail.                  Reducer.
Bin V.............................       0.60-0.79             0.7  Basic Combinations...
Bin VI............................       0.80-1.19             1.0  Advanced Combinations  .....................
                                                                     (including SmartWay
                                                                     Elite).
Bin VII...........................       1.20-1.59             1.4  Optimized              .....................
                                                                     Combinations.
Bin VIII..........................           > 1.6             1.8  Changes to Trailer     .....................
                                                                     Construction.
----------------------------------------------------------------------------------------------------------------
Note: A blank cell indicates a zero or NA value in this table.

    The agencies used EPA's Greenhouse gas Emissions Model (GEM) 
vehicle simulation tool to conduct this analysis. See Section F.1 below 
for more about GEM. Within GEM, the aerodynamic performance of each 
trailer subcategory is evaluated by subtracting the delta 
CDA shown in Table IV-4 from the CDA value 
representing a specific standard tractor pulling a zero-technology 
trailer. The agencies chose to model the zero-technology long box dry 
van using a CDA value of 6.2 m\2\ (the average 
CDA from EPA's coastdown testing). For long box refrigerated 
vans, a two percent reduction in CDA was assumed to account 
for the aerodynamic benefit of the TRU at the front of the trailer. 
Short box dry vans also received a two percent lower CDA 
value compared to its 53-foot counterpart, consistent with the 
reduction observed in EPA's wind tunnel testing. The CDA 
value assigned to the refrigerated short box vans was an

[[Page 40264]]

additional two percent lower than the short box dry van. Non-aero box 
trailers are modeled as short box dry vans. The trailer subcategories 
that have design standards (i.e., non-box and non-aero box trailers) do 
not have numerical standards to meet, but they were evaluated in this 
feasibility analysis in order to quantify the benefits of including 
them in the program. Non-aero box trailers are modeled as short dry 
vans. Non-box trailers, which are modeled as flatbed trailers, were 
assigned a drag area of 4.9 m\2\, as was done in the Phase 1 tractor 
program for low roof day cabs. Table IV-5 illustrates the Bin I drag 
areas (CDA) associated with each trailer subcategory.

    Table IV-5--Baseline CDA Values Associated With Aerodynamic Bin I
                       [Zero trailer technologies]
------------------------------------------------------------------------
                   Trailer subcategory                        Dry van
------------------------------------------------------------------------
Long Dry Van............................................             6.2
Short Dry Van...........................................             6.1
Long Ref. Van...........................................             6.1
Short Ref. Van..........................................             6.0
Non-Aero Box............................................             6.1
Non-Box.................................................             4.9
------------------------------------------------------------------------

(b) Tire Rolling Resistance
    Similar to the proposed Phase 2 tractor and vocational vehicle 
programs, the agencies are proposing a tire program based on adoption 
of lower rolling resistance tires. Feedback from several box trailer 
manufacturers indicates that the standard tires offered on their new 
trailers are SmartWay-verified tires (i.e., CRR of 5.1 kg/
ton or better). An informal survey of members from the Truck Trailer 
Manufacturers Association (TTMA) indicates about 35 percent of box 
trailers sold today have SmartWay tires.\229\ While some trailers 
continue to be sold with tires of higher rolling resistances, the 
agencies believe most box trailer tires currently achieve the Phase 1 
trailer tire CRR of 6.0 kg/ton or better.
---------------------------------------------------------------------------

    \229\ Truck Trailer Manufacturers Association letter to EPA. 
Received on October 16, 2014. Docket EPA-HQ-OAR-2014-0827.
---------------------------------------------------------------------------

    The agencies evaluated two levels of tire performance for this 
proposal beyond the baseline trailer tire rolling resistance level 
(TRRL) of 6.0 kg/ton. The first performance level was set at the 
criteria for SmartWay-verification for trailer tires, 5.1 kg/ton, which 
is a 15 percent reduction in CRR from the baseline. As 
mentioned previously, several tire models available today achieve 
rolling resistance values well below the present SmartWay threshold. 
Given the multiple year phase-in of the standards, the agencies expect 
that tire manufacturers will continue to respond to demand for more 
efficient tires and will offer increasing numbers of tire models with 
rolling resistance values significantly better than today's typical LRR 
tires. In this context, we believe it is reasonable to expect a large 
fraction of the trailer industry could adopt tires with rolling 
resistances at a second performance level that would achieve an 
additional eight percent reduction in rolling resistance (a 22 percent 
reduction from the baseline tire), especially in the later stages of 
the program. The agencies project the CRR for this second 
level of performance to be a value of 4.7 kg/ton.
    The agencies evaluated these three tire rolling resistance levels, 
summarized in Table IV-6, in the feasibility analysis of the following 
sections. GEM simulations that apply Level 1 and 2 tires result in 
CO2 and fuel consumption reductions of two and three percent 
from the baseline tire, respectively. It should be noted that these 
levels are for the feasibility analysis only. For compliance, 
manufacturers would have the option to use tires with any rolling 
resistance and would not be limited to these TRRLs.

 Table IV-6--Summary of Trailer Tire Rolling Resistance Levels Evaluated
------------------------------------------------------------------------
                                                                CRR (kg/
                Tire rolling resistance level                     ton)
------------------------------------------------------------------------
Baseline.....................................................        6.0
Level 1......................................................        5.1
Level 2......................................................        4.7
------------------------------------------------------------------------

(c) Automatic Tire Inflation Systems
    NHTSA and EPA recognize the role of proper tire inflation in 
maintaining optimum tire rolling resistance during normal trailer 
operation. For this proposal, rather than require performance testing 
of ATI systems, the agencies are proposing to recognize the benefits of 
ATI systems with a single default reduction for manufacturers that 
incorporate ATI systems into their trailer designs. Based on 
information available today, we believe that there is a narrow range of 
performance among technologies available and among systems in typical 
use. We propose to assign a 1.5 percent reduction in CO2 and 
fuel consumption for all trailers that implement ATI systems, based on 
information available today.\230\ We believe the use of these systems 
can consistently ensure that tire pressure and tire rolling resistance 
are maintained. We selected the levels of the proposed trailer 
standards with the expectation that a high rate of adoption of ATI 
systems would occur across all on-highway trailers and during all years 
of the phase-in of the program. See Section IV.D.3.d below for 
discussion of our estimates of these factors, as well as estimates of 
the degree of adoption of ATI systems prior to and at various points in 
the phase-in of the proposed program. The informal survey of members 
from the Truck Trailer Manufacturers Association (TTMA) indicates about 
40 percent of box trailers sold today have ATI systems.\231\
---------------------------------------------------------------------------

    \230\ See the Chapter 2.10.2.3 of the draft RIA.
    \231\ Truck Trailer Manufacturers Association letter to EPA. 
Received on October 16, 2014. Docket EPA-HQ-OAR-2014-0827
---------------------------------------------------------------------------

(d) Weight Reduction
    The agencies are proposing compliance provisions that would limit 
the weight-reduction options to the substitution of specified 
components that can be clearly isolated from the trailer as a whole. 
For this proposal, the agencies have identified several conventional 
components with available lighter-weight substitutes (e.g., 
substituting conventional dual tires mounted on steel wheels with wide-
based single tires mounted on aluminum wheels). We are proposing values 
for the associated weight-related savings that would be applied with 
these substitutions for compliance. The proposed component 
substitutions and their associated weight savings are presented in the 
draft RIA, Chapter 2.10.2.4 and in proposed 40 CFR 1037.515. We believe 
that the initial cost of these component substitutions is currently 
substantial enough that only a relatively small segment of the industry 
has adopted these technologies today.
    The agencies recognize that when weight reduction is applied to a 
trailer, some operators will replace that saved weight with additional 
payload. To account for this in EPA's GEM vehicle simulation tool, it 
is assumed that one-third of the weight reduction will be applied to 
the payload. For tractor-trailers simulated in GEM, it takes a weight 
reduction of nearly 1,000 lbs before a one percent fuel savings is 
achieved. The component substitutions identified by the agencies result 
in weight reductions of less than 500 lbs, yet can cost over $1,000. 
The agencies believe that few trailer manufacturers would apply weight 
reduction solely as a means of achieving reduced fuel consumption and 
CO2 emissions. Therefore, we are proposing standards that 
could be met without reducing weight--that is, the compliance path set

[[Page 40265]]

out by the agencies for the proposed standards does not include weight 
reduction. However, we are proposing to offer weight reduction as an 
option for box trailer manufacturers who wish to apply it to some of 
their trailers as part of their compliance strategy.
    The agencies have identified 11 common trailer components that have 
lighter weight options available (see 40 CFR 1037.515) 
232 233 234 235 Manufacturers that adopt these technologies 
would sum the associated weight reductions and apply those values in 
GEM. As mentioned previously, we are restricting the weight reduction 
options to those listed in 40 CFR 1037.515. We are requesting comment 
on the appropriateness of the specified weight reductions from 
component substitution. In addition, we seek weight and cost data 
regarding additional components that could be offered as specific 
weight reduction options. The agencies request that any such components 
be applicable to most box trailers, and that the reduced weight option 
not currently be in common use.
---------------------------------------------------------------------------

    \232\ Scarcelli, Jamie. ``Fuel Efficiency for Trailers'' 
Presented at ACEEE/ICCT Workshop: Emerging Technologies for Heavy-
Duty Vehicle Fuel Efficiency, Wabash National Corporation. July 22, 
2014.
    \233\ ``Weight Reduction: A Glance at Clean Freight 
Strategies'', EPA SmartWay. EPA420F09-043. Available at: http://permanent.access.gpo.gov/gpo38937/EPA420F09-043.pdf.
    \234\ Memorandum dated June 2015 regarding confidential weight 
reduction information obtained during SBREFA Panel. Docket EPA-HQ-
OAR-2014-0827.
    \235\ Randall Scheps, Aluminum Association, ``The Aluminum 
Advantage: Exploring Commercial Vehicles Applications,'' presented 
in Ann Arbor, Michigan, June 18, 2009.
---------------------------------------------------------------------------

(3) Effectiveness, Adoption Rates, and Costs of Technologies for the 
Proposed Standards
    The agencies evaluated the technologies above as they apply to each 
of the trailer subcategories. The next sections describe the 
effectiveness, adoption rates and costs associated with these 
technologies. The effectiveness and adoption rates are then used to 
derive the proposed standards.
(a) Zero-Technology Baseline Tractor-Trailer Vehicles
    The regulatory purpose of EPA's heavy-duty vehicle compliance tool, 
GEM, is to combine the effects of trailer technologies through 
simulation so that they can be expressed as g/ton-mile and gal/1000 
ton-mile and thus avoid the need for direct testing of each trailer 
model being certified. The proposed trailer program has separate 
standards for each trailer subcategory, and a unique tractor-trailer 
vehicle was chosen to represent each subcategory for compliance. In the 
Phase 2 update to GEM, each trailer subcategory is modeled as a 
particular trailer being pulled by a standard tractor depending on the 
physical characteristics and use pattern of the trailer. Table IV-7 
highlights the relevant vehicle characteristics for the zero-technology 
baseline of each subcategory. Baseline trailer tires are used, and the 
drag area, which is a function of the aerodynamic characteristics of 
both the tractor and trailer, is set to the Bin I values shown 
previously in Table IV-5. Weight reduction and ATI systems are not 
applied in these baselines. Chapter 2.10 of the draft RIA provides a 
detailed description of the development of these baseline tractor-
trailers.
    The agencies chose to consistently model a Class 8 tractor across 
all trailer subcategories. We recognize that Class 7 tractors are 
sometimes used in certain applications. However, we believe Class 8 
tractors are more widely available, which will make it easier for 
trailer manufacturers to obtain a qualified tractor if they choose to 
perform trailer testing. We request comment on the use of Class 8 
tractors as part of the tractor-trailer vehicles used in the compliance 
simulation as well as performance testing. We ask that commenters 
include data, where available, related to the current use and 
availability of Class 7 and 8 tractors with respect to the trailer 
types in each trailer subcategory.

                                  Table IV--7 Characteristics of the Zero-Technology Baseline Tractor-Trailer Vehicles
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                  Dry van
                                             Refrigerated van                Non-aero box           Non-box
                                 -----------------------------------------------------------------------------------------------------------------------
Trailer Length..................  Long..............  Short.............  Long..............  Short.............  All Lengths.......  All Lengths
Tractor Class...................  Class 8...........  Class 8...........  Class 8...........  Class 8...........  Class 8...........  Class 8
Tractor Cab Type................  Sleeper...........  Day...............  Sleeper...........  Day...............  Day...............  Day
Tractor Roof Height.............  High..............  High..............  High..............  High..............  High..............  Low
Engine..........................  2018 MY 15L,......  2018 MY 15L,......  2018 MY 15L,......  2018 MY 15L,......  2018 MY 15L,......  2018 MY 15L,
                                  455 HP............  455 HP............  455 HP............  455 HP............  455 HP............  455 HP
Frontal Area (m\2\).............  10.4..............  10.4..............  10.4..............  10.4..............  10.4..............  6.9
Drag Area, CDA (m\2\)...........  6.2...............  6.1...............  6.1...............  6.0...............  6.1...............  4.9
Steer Tire RR (kg/ton)..........  6.54..............  6.54..............  6.54..............  6.54..............  6.54..............  6.54
Drive Tire RR (kg/ton)..........  6.92..............  6.92..............  6.92..............  6.92..............  6.92..............  6.92
Trailer Tire RR (kg/ton)........  6.00..............  6.00..............  6.00..............  6.00..............  6.00..............  6.00
Total Weight (kg)...............  31,978............  21,028............  33,778............  22,828............  21,028............  29,710
Payload (tons)..................  19................  10................  19................  10................  10................  19
ATI System Use..................  0.................  0.................  0.................  0.................  0.................  0
Weight Reduction (lb)...........  0.................  0.................  0.................  0.................  0.................  0
Drive Cycle Weightings..........  ..................  ..................  ..................  ..................  ..................  ..................
65-MPH Cruise...................  86%...............  64%...............  86%...............  64%...............  64%...............  64%
55-MPH Cruise...................  9%................  17%...............  9%................  17%...............  17%...............  17%
Transient Driving...............  5%................  19%...............  5%................  19%...............  19%...............  19%
--------------------------------------------------------------------------------------------------------------------------------------------------------

(b) Effectiveness of Technologies
    The agencies are proposing to recognize trailer improvements via 
four performance parameters: aerodynamic drag reduction, tire rolling 
resistance reduction, the adoption of ATI systems, and by substituting 
specific weight-reducing components. Table IV-8 summarizes the 
performance levels for each of these parameters based on the technology 
characteristics outlined in Section IV. D. (2) .

[[Page 40266]]



   Table IV--8 Performance Parameters for the Proposed Trailer Program
------------------------------------------------------------------------
 
------------------------------------------------------------------------
Aerodynamics (Delta CDA, m\2\):
  Bin I...................................  0.0.
  Bin II..................................  0.1.
  Bin III.................................  0.3.
  Bin IV..................................  0.5.
  Bin V...................................  0.7.
  Bin VI..................................  1.0.
  Bin VII.................................  1.4.
  Bin VIII................................  1.8.
Tire Rolling Resistance (CRR, kg/ton):
  Tire Baseline...........................  6.0.
  Tire Level 1............................  5.1.
  Tire Level 2............................  4.7.
Tire Inflation System (% reduction):
  ATI System..............................  1.5.
Weight Reduction (lbs):
  Weight..................................  1/3 added to payload,
                                             remaining reduces overall
                                             vehicle weight.
------------------------------------------------------------------------

    These performance parameters have different effects on each trailer 
subcategory due to differences in the simulated trailer 
characteristics. Table IV-9 shows the agencies' estimates of the 
effectiveness of each parameter for the four box trailer subcategories. 
Each technology was evaluated using the baseline parameter values for 
the other technology categories. For example, each aerodynamic bin was 
evaluated using the baseline tire (6.0 kg/ton) and the baseline weight 
reduction option (zero lbs). The table shows that aerodynamic 
improvements offer the largest potential for CO2 emissions 
and fuel consumption reductions, making them relatively effective 
technologies.

 Table IV-9--Effectiveness (Percent CO2 and Fuel Savings From Baseline) of Technologies for the Proposed Trailer
                                                     Program
----------------------------------------------------------------------------------------------------------------
                                                              Dry van                    Refrigerated van
         Aerodynamics           Delta CDA (m\2\) ---------------------------------------------------------------
                                                       Long            Short           Long            Short
----------------------------------------------------------------------------------------------------------------
Bin I.........................  0.0.............              0%              0%              0%              0%
Bin II........................  0.1.............              -1              -1              -1              -1
Bin III.......................  0.3.............              -2              -2              -2              -2
Bin IV........................  0.5.............              -3              -4              -3              -3
Bin V.........................  0.7.............              -5              -5              -5              -5
Bin VI........................  1.0.............              -7              -7              -7              -7
Bin VII.......................  1.4.............             -10             -10              -9             -10
Bin VIII......................  1.8.............             -13             -13             -12             -12
----------------------------------------------------------------------------------------------------------------
Tire Rolling Resistance         CRR (kg/ton)....              Dry van
                                        Refrigerated van
                                                 ---------------------------------------------------------------
                                                            Long           Short            Long           Short
----------------------------------------------------------------------------------------------------------------
Baseline......................  6.0.............               0               0               0               0
Level 1.......................  5.1.............              -2              -1              -2              -1
Level 2.......................  4.7.............              -3              -2              -3              -2
----------------------------------------------------------------------------------------------------------------
Weight Reduction                Weight (lb).....              Dry van
                                        Refrigerated van
                                                 ---------------------------------------------------------------
                                                            Long           Short            Long           Short
----------------------------------------------------------------------------------------------------------------
Baseline......................  0.0.............             0.0             0.0             0.0             0.0
Al. Dual Wheels...............  168.............            -0.2            -0.3            -0.2            -0.3
Upper Coupler.................  280.............            -0.3              -1            -0.3              -1
Suspension....................  430.............            -0.5              -1            -0.5              -1
Al. Single Wide...............  556.............              -1              -1              -1              -1
----------------------------------------------------------------------------------------------------------------

(c) Reference Tractor-Trailer To Evaluate Benefits and Costs
    In order to evaluate the benefits and costs of the proposed 
standards, it is necessary to establish a reference point for 
comparison. As mentioned previously, the technologies described in 
Section IV. D. (2) exist in the market today, and their adoption is 
driven by available fuel savings as well as by the voluntary SmartWay 
Partnership and California's tractor-trailer requirements. For this 
proposal, the agencies identified reference case tractor-trailers for 
each trailer subcategory based on the technology adoption rates we 
project would exist if this proposed trailer program was not 
implemented.
    We project that by 2018, absent further California regulation, 
EPA's SmartWay program and these research programs will result in about 
20 percent of 53-foot dry and refrigerated vans adopting basic 
SmartWay-level aerodynamic technologies (meeting SmartWay's four 
percent verification level and Bin III from Table IV-5), 30 percent 
adopting more advanced aerodynamic technologies at the five percent 
SmartWay-verification level (Bin IV from Table IV-5) and five percent 
adding combinations of technologies (Bin V).236 237 238 In 
addition, we project half of these 53' box trailers will be equipped 
with SmartWay-verified tires (i.e., 5.1 kg/ton or better) and ATI 
systems as well. The agencies project that market forces will drive an 
additional one percent increase in adoption of the advanced SmartWay 
and tire technologies each year through 2027. For analytical purposes, 
the agencies assumed manufacturers of the shorter box trailers and 
other trailer

[[Page 40267]]

subcategories would not adopt these technologies in the timeframe 
considered and a zero-technology baseline is assumed. We are not 
assuming weight reduction for any of the trailer subcategories in the 
reference cases. Table IV-10 summarizes the reference case trailers for 
each trailer subcategory.
---------------------------------------------------------------------------

    \236\ Truck Trailer Manufacturers Association letter to EPA. 
Received on October 16, 2014. Docket EPA-HQ-OAR-2014-0827.
    \237\ Ben Sharpe (ICCT) and Mike Roeth (North American Council 
for Freight Efficiency), ``Costs and Adoption Rates of Fuel-Saving 
Technologies for Trailer in the North American On-Road Freight 
Sector'', Feb 2014.
    \238\ Frost & Sullivan, ``Strategic Analysis of North American 
Semi-trailer Advanced Technology Market'', Feb 2013.

  Table IV-10--Projected Adoption Rates and Average Performance Parameters for the Less Dynamic Reference Case
                                                    Trailers
----------------------------------------------------------------------------------------------------------------
           Technology                            Long box  dry & refrigerated vans                Short box, non-
-------------------------------------------------------------------------------------------------   aero box, &
                                                                                                      non-box
                                                                                                     trailers
           Model Year                  2018            2021            2024            2027      ---------------
                                                                                                     2018-2027
----------------------------------------------------------------------------------------------------------------
Aerodynamics:
    Bin I.......................             45%             41%             38%             35%            100%
    Bin II......................  ..............  ..............  ..............  ..............  ..............
    Bin III.....................              20              20              20              20  ..............
    Bin IV......................              30              34              37              40  ..............
    Bin V.......................               5               5               5               5  ..............
    Bin VI......................  ..............  ..............  ..............  ..............  ..............
    Bin VII.....................  ..............  ..............  ..............  ..............  ..............
    Bin VIII....................  ..............  ..............  ..............  ..............  ..............
        Average Delta CDA (m\2\)             0.2             0.3             0.3             0.3             0.0
         \a\....................
Tire Rolling Resistance:
    Baseline tires..............              50              47              43              40             100
    Level 1 tires...............              50              53              57              60  ..............
    Level 2 tires...............  ..............  ..............  ..............  ..............  ..............
        Average CRR (kg/ton) \a\            5.55            5.52            5.49            5.46             6.0
Tire Inflation:
    ATI.........................              50              53              57              60               0
        Average % Reduction \a\.             0.8             0.8             0.9             0.9             0.0
Weight Reduction (lbs):
    Weight \b\..................  ..............  ..............  ..............  ..............  ..............
----------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
\a\ Combines adoption rates with performance levels shown in Table IV-8.
\b\ Weight reduction was not projected for the reference case trailers.

    Also shown in Table IV-10 are average aerodynamic performance 
(delta CDA), average tire rolling resistance 
(CRR), and average reductions due to use of ATI and weight 
reduction for each stage of the proposed program. These values indicate 
the performance of theoretical average tractor-trailers that the 
agencies project will be in use if no federal regulations were in place 
for trailer CO2 and fuel consumption. The average tractor-
trailer vehicles serve as reference cases for each trailer subcategory. 
The agencies provide a detailed description of the development of these 
reference case vehicles in Chapter 2.10 in the draft RIA.
    Because the agencies cannot be certain about future trends, we also 
considered a second reference case. This more dynamic reference case 
reflects the possibility that absent a Phase 2 regulation, there will 
be continuing adoption of technologies in the trailer market after 2027 
that reduce fuel consumption and CO2 emissions. This case 
assumes the research funded and conducted by the federal government, 
industry, academia and other organizations will, after 2027, result the 
adoption of some technologies beyond the levels required to comply with 
existing regulatory and voluntary programs. One example of such 
research is the Department of Energy Super Truck program which has a 
goal of demonstrating cost-effective measures to improve the efficiency 
of Class 8 long-haul freight trucks by 50 percent by 2015.\239\ This 
reference case assumes that by 2040, 75 percent of new trailers will be 
equipped with SmartWay-verified aerodynamic devices, low rolling 
resistance tires, and ATI systems. Table IV-11 shows the agencies' 
projected adoption rates of technologies in the more dynamic reference 
case.
---------------------------------------------------------------------------

    \239\ Daimler Truck North America. SuperTruck Program Vehicle 
Project Review. June 19, 2014. Docket EPA-HQ-OAR-2014-0827.

                      Table IV-11--Projected Adoption Rates and Average Performance Parameters for the More Dynamic Reference Case
--------------------------------------------------------------------------------------------------------------------------------------------------------
                       Technology                                                Long box dry & refrigerated vans                         Short box, non-
-----------------------------------------------------------------------------------------------------------------------------------------   aero box, &
                                                                                                                                              non-box
                                                                                                                                             trailers
                       Model year                              2018            2021            2024            2027            2040      ---------------
                                                                                                                                             2018-2027
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aerodynamics:
    Bin I...............................................             45%             41%             38%             35%             20%            100%
    Bin II..............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin III.............................................              20              20              20              20              20  ..............

[[Page 40268]]

 
    Bin IV..............................................              30              34              37              40              55  ..............
    Bin V...............................................               5               5               5               5               5  ..............
    Bin VI..............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin VII.............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin VIII............................................  ..............  ..............  ..............  ..............  ..............  ..............
        Average Delta C DA (m\2\) \a\...................             0.2             0.3             0.3             0.3             0.4             0.0
Tire Rolling Resistance:
    Baseline tires......................................              50              47              43              40              25             100
    Level 1 tires.......................................              50              53              57              60              75  ..............
    Level 2 tires.......................................  ..............  ..............  ..............  ..............  ..............  ..............
        Average CRR (kg/ton) \a\........................             5.6             5.5             5.5             5.5             5.3             6.0
Tire Inflation:
ATI.....................................................              50              53              57              60              75               0
        Average % Reduction \a\.........................             0.8             0.8             0.9             0.9             1.1             0.0
Weight Reduction (lbs):
    Weight \b\..........................................  ..............  ..............  ..............  ..............  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
\a\ Combines adoption rates with performance levels shown in Table IV-8.
\b\ Weight reduction was not projected for the reference case trailers.

    The agencies applied the vehicle attributes from Table IV-7 and the 
average performance values from Table IV-10 in the proposed Phase 2 GEM 
vehicle simulation to calculate the CO2 emissions and fuel 
consumption performance of the reference tractor-trailers. The results 
of these simulations are shown in Table IV-12. We used these 
CO2 and fuel consumption values to calculate the relative 
benefits of the proposed standards. Note that the large difference 
between the per ton-mile values for long and short trailers is due 
primarily to the large difference in assumed payload (19 tons compared 
to 10 tons) as seen in Table IV-7 and discussed further in the Chapter 
2.10.3. The alternative reference case shown in Table IV-11 impacts the 
long-term projections of benefits beyond 2027, which are analyzed in 
Chapters 5-7 of the draft RIA.

           Table IV-12--CO2 Emissions and Fuel Consumption Results for the Reference Tractor-Trailers
----------------------------------------------------------------------------------------------------------------
                                                              Dry van                    Refrigerated van
                     Length                      ---------------------------------------------------------------
                                                       Long            Short           Long            Short
----------------------------------------------------------------------------------------------------------------
CO2 Emissions (g/ton-mile)......................              85             147              87             151
Fuel Consumption (gal/1000 ton-miles)...........          8.3497         14.4401          8.5462         14.8330
----------------------------------------------------------------------------------------------------------------

(d) Projected Technology Adoption Rates for the Proposed Standards
    As described in Section IV. E., the agencies evaluated several 
alternatives for the proposed trailer program. Based on our analysis, 
and current information, the agencies are proposing the alternative we 
believe reflects the agencies' respective statutory authorities. The 
agencies are also considering an accelerated alternative with less lead 
time, requiring the same incremental stringencies for the proposed 
program, but becoming effective three years earlier. The agencies 
believe this alternative has the potential to be the maximum feasible 
alternative. However, based on the evidence currently before us, EPA 
and NHTSA have outstanding questions regarding relative risks and 
benefits of Alternative 4 due to the timeframe envisioned by that 
alternative. EPA and NHTSA are seriously considering this accelerated 
alternative in whole or in part for the trailer segment. In other 
words, the agencies could determine that less lead-time is maximum 
feasible in the final rule. We request comment on these two 
alternatives, including the proposed lead-times.
    Table IV-13 and Table IV-14 present a set of assumed adoption rates 
for aerodynamic, tire, and ATI technologies that a manufacturer could 
apply to meet the proposed standards. These adoption rates begin with 
60 percent of long box trailers achieving current SmartWay level 
aerodynamics (Bin IV) and progress to 90 percent achieving SmartWay 
Elite (Bin VI) or better over the following nine years. The adoption 
rates for short box trailers assume adoption of single aero devices in 
MY 2021 and combinations of devices by MY 2027. Although the shorter 
lengths of these trailers can restrict the design of aerodynamic 
technologies that fully match the SmartWay-like performance levels of 
long boxes, we nevertheless expect that trailer and device 
manufacturers would continue to innovate skirt, under-body, rear, and 
gap-reducing devices and combinations to achieve improved aerodynamic 
performance on these shorter trailers. The assumed adoption rates for 
aerodynamic technologies for both long and short refrigerated vans are 
slightly less than for dry vans, reflecting the more limited number of 
aerodynamic options due to the presence of their TRUs.
    The gradual increase in assumed adoption of aerodynamic 
technologies

[[Page 40269]]

throughout the phase-in to the MY 2027 standards recognizes that even 
though many of the technologies are available today and technologically 
feasible throughout the phase-period, their adoption on the scale of 
the proposed program would likely take time. The adoption rates we are 
assuming in the interim years--and the standards that we developed from 
these rates--represent steady and yet reasonable improvement in average 
aerodynamic performance.
    The agencies project that nearly all box trailers will adopt tire 
technologies to comply with the standards and the agencies projected 
consistent adoption rates across all lengths of dry and refrigerated 
vans, with more advanced (Level 2) low-rolling resistance tires assumed 
to replace Level 1 tire models in the 2024 time frame, as Level 2-type 
tires become more available and fleet experience with these tires 
develops. As mentioned previously, the agencies did not include weight 
reduction in their technology adoption projections, but certain types 
of weight reduction could be used as a compliance pathway, as discussed 
in Section IV.D.1.d above.
    The adoption rates shown in these tables are one set of many 
possible combinations that box trailer manufacturers could apply to 
achieve the same average stringency. If a manufacturer chose these 
adoption rates, a variety of technology options exist within the 
aerodynamic bins, and several models of LRR tires exist for the levels 
shown. Alternatively, technologies from other aero bins and tire levels 
could be used to comply. It should be noted that manufacturers are not 
limited to aerodynamic and tire technologies, since these are 
performance-based standards, and manufacturers would not be constrained 
to adopt any particular way to demonstrate compliance. Certain types of 
weight reduction, for example, may be used as a compliance pathway, as 
discussed in Section IV.D.1.d above.
    Similar to our analyses of the reference cases, the agencies 
derived a single set of performance parameters for each subcategory by 
weighting the performance levels included in Table IV-8 by the 
corresponding adoption rates. These performance parameters represent an 
average compliant vehicle for each trailer subcategory and we present 
these values in the tables. The 2024 MY adoption rates would continue 
to apply for the partial-aero box trailers in 2027 and later model 
years.

                             Table IV-13--Projected Adoption Rates and Average Performance Parameters for Long Box Trailers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                           Technology                                          Long box dry vans                      Long box refrigerated vans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                           Model year                                2018       2021       2024       2027       2018       2021       2024       2027
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aerodynamic Technologies:
    Bin I.......................................................         5%  .........  .........  .........         5%  .........  .........  .........
    Bin II......................................................  .........  .........  .........  .........  .........  .........  .........  .........
    Bin III.....................................................        30%         5%  .........  .........        30%         5%  .........  .........
    Bin IV......................................................        60%        55%        25%  .........        60%        55%        25%  .........
    Bin V.......................................................         5%        10%        10%        10%         5%        10%        10%        20%
    Bin VI......................................................  .........        30%        65%        50%  .........        30%        65%        60%
    Bin VII.....................................................  .........  .........  .........        40%  .........  .........  .........        20%
    Bin VIII....................................................  .........  .........  .........  .........  .........  .........  .........  .........
        Average Delta CDA (m\2\) \a\............................        0.4        0.7        0.8        1.1        0.4        0.7        0.8        1.0
Trailer Tire Rolling Resistance:
    Baseline tires..............................................        15%         5%         5%         5%        15%         5%         5%         5%
    Level 1 tires...............................................        85%        95%  .........  .........        85%        95%  .........  .........
    Level 2 tires...............................................  .........  .........        95%        95%  .........  .........        95%        95%
        Average CRR (kg/ton) \a\................................        5.2        5.1        4.8        4.8        5.2        5.1        4.8        4.8
Tire Inflation System:
    ATI.........................................................         85         95         95         95         85         95         95         95
        Average ATI Reduction (%) \a\...........................       1.3%       1.4%       1.4%       1.4%       1.3%       1.4%       1.4%       1.4%
Weight Reduction (lbs):
    Weight \b\..................................................  .........  .........  .........  .........  .........  .........  .........  .........
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
\a\ Combines projected adoption rates with performance levels shown in Table IV-8.
\b\ This set of proposed adoption rates did not apply any assumed weight reduction to meet the proposed standards for these trailers.


                             Table IV-14--Projected Adoption Rates and Average Performance Parameters for Short Box Trailers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                           Technology                                         Short box dry vans                      Short box refrigerated vans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                           Model year                                2018       2021       2024       2027       2018       2021       2024       2027
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aerodynamic Technologies: \a\
    Bin I.......................................................       100%         5%  .........  .........       100%         5%  .........  .........
    Bin II......................................................  .........        95%        70%        30%  .........        95%        70%        55%
    Bin III.....................................................  .........  .........        30%        60%  .........  .........        30%        40%
    Bin IV......................................................  .........  .........  .........        10%  .........  .........  .........         5%
    Bin V.......................................................  .........  .........  .........  .........  .........  .........  .........  .........
    Bin VI......................................................  .........  .........  .........  .........  .........  .........  .........  .........
    Bin VII.....................................................  .........  .........  .........  .........  .........  .........  .........  .........
    Bin VIII....................................................  .........  .........  .........  .........  .........  .........  .........  .........
        Average Delta CDA (m\2\) \b\............................        0.4        0.7        0.8        1.1        0.4        0.7        0.8        1.0
Trailer Tire Rolling Resistance:
    Baseline tires..............................................        15%         5%         5%         5%        15%         5%         5%         5%
    Level 1 tires...............................................        85%        95%  .........  .........        85%        95%  .........  .........
    Level 2 tires...............................................  .........  .........        95%        95%  .........  .........        95%        95%
        Average CRR (kg/ton) \b\................................        5.2        5.1        4.8        4.8        5.2        5.1        4.8        4.8

[[Page 40270]]

 
Tire Inflation System:
ATI.............................................................        85%        95%        95%        95%        85%        95%        95%        95%
        Average ATI Reduction (%) \c\...........................       1.3%       1.4%       1.4%       1.4%       1.3%       1.4%       1.4%       1.4%
Weight Reduction (lbs):
    Weight \b\..................................................  .........  .........  .........  .........  .........  .........  .........  .........
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
\a\ The majority of short box trailers are 28 feet in length. We recognize that they are often operated in tandem, which limits the technologies that
  can be applied (for example, boat tails).
\b\ Combines projected adoption rates with performance levels shown in Table IV-8.
\c\ This set of proposed adoption rates did not apply any assumed weight reduction to meet the proposed standards for these trailers.

    Non-aero box trailers, with two or more work-related special 
components, and non-box trailers are not shown in the tables above. We 
are proposing that manufacturers of these trailers meet design-based 
(i.e., technology-based) standards, instead of performance-based 
standards that would apply to other trailers. That is, manufacturers of 
these trailers would not need to use aerodynamic technologies, but they 
would need to use appropriate lower rolling resistance tires and ATI 
systems, based on our assessments of the typical CO2 and 
fuel consumption performance of this equipment (see Section IV.2.c). 
Thus, we are projecting 100 percent adoption rates of these 
technologies at each stage of the program. Compared to manufacturers 
that needed aerodynamic technologies to comply, the approach for non-
aero box trailers and non-box trailers would result in a significantly 
lower compliance burden for manufacturers by reducing the amount of 
tracking and eliminating the need to calculate a compliance value (see 
Section IV. F.). The agencies are proposing these design standards in 
two stages. In 2018, the proposed standards would require manufacturers 
to use tires meeting a rolling resistance of Level 1 or better and to 
install ATI systems on all non-box and non-aero box trailers. In 2024, 
the proposed standards would require manufacturers to use LRR tires at 
a Level 2 or better, and to still install ATI systems. We seek comment 
on all aspects of this design-based standards concept. We also seek 
comment on providing manufacturers with the option of adopting Level 2 
tires in the early years of the program (MY 2018-2023) and avoiding the 
use of ATI systems if they chose.

 Table IV-15--Projected Adoption Rates and Average Performance Parameters for Non-Aero Box and Non-Box Trailers
----------------------------------------------------------------------------------------------------------------
                   Technology                                     Non-aero box & non-box trailers
----------------------------------------------------------------------------------------------------------------
                   Model year                          2018            2021            2024            2027
----------------------------------------------------------------------------------------------------------------
Aerodynamic Technologies:
    Bin I.......................................            100%            100%            100%            100%
    Bin II......................................  ..............  ..............  ..............  ..............
    Bin III.....................................  ..............  ..............  ..............  ..............
    Bin IV......................................  ..............  ..............  ..............  ..............
    Bin V.......................................  ..............  ..............  ..............  ..............
    Bin VI......................................  ..............  ..............  ..............  ..............
    Bin VII.....................................  ..............  ..............  ..............  ..............
    Bin VIII....................................  ..............  ..............  ..............  ..............
        Average Delta CDA (m\2\) \a\............             0.0             0.0             0.0             0.0
Trailer Tire Rolling Resistance:
    Baseline tires..............................  ..............  ..............  ..............  ..............
    Level 1 tires...............................            100%            100%  ..............  ..............
    Level 2 tires...............................  ..............  ..............            100%            100%
        Average CRR (kg/ton) \a\................             5.1             5.1             4.7             4.7
Tire Inflation System:
    ATI.........................................            100%            100%            100%            100%
        Average ATI Reduction (%) \a\...........            1.5%            1.5%            1.5%            1.5%
Weight Reduction (lbs):
    Weight \b\..................................  ..............  ..............  ..............  ..............
----------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
\a\ Combines projected adoption rates with performance levels shown in Table IV-8.
\b\ This set of adoption rates did not apply weight reduction to meet the proposed standards for these trailers.

    We request comment and any data related to our projections of 
technology adoption rates. The following section (d) explains how the 
agencies combined these adoption rates with the performance values 
shown previously to calculate the proposed standards.
(e) Derivation of the Proposed Standards
    The average performance parameters from Table IV-14, and Table IV-
15 were applied as input values to the GEM vehicle simulation to derive 
the

[[Page 40271]]

proposed HD Phase 2 fuel consumption and CO2 emissions 
standards for each subcategory of trailers. The proposed standards are 
shown in Table IV-16. The proposed standards for partial-aero trailers, 
which are not explicitly shown in Table IV-16, would be the same as 
their full-aero counterparts through MY 2026. In MY 2027 and later, 
partial aero trailers would continue to meet the MY 2024 standards.
    Over the four stages of the proposed rule, box trailers longer than 
50 feet would, on average, reduce their CO2 emissions and 
fuel consumption by two percent, four percent, seven percent and eight 
percent compared to their reference cases. Box trailers 50-feet and 
shorter would achieve reductions of two percent, three percent and four 
percent compared to their reference cases. The tire technologies used 
on non-box and non-aero box trailers would provide reductions of two 
percent in the first two stages and achieve three percent by 2027.

                                Table IV-16--Proposed Standards for Box Trailers
----------------------------------------------------------------------------------------------------------------
                                   Subcategory                Dry van                    Refrigerated van
          Model year           ---------------------------------------------------------------------------------
                                     Length            Long            Short           Long            Short
----------------------------------------------------------------------------------------------------------------
2018--2020....................  EPA Standard                  83             144              84             147
                                 (CO2 Grams per
                                 Ton-Mile).
                                Voluntary NHTSA           8.1532         14.1454          8.2515         14.4401
                                 Standard
                                 (Gallons per
                                 1,000 Ton-Mile).
2021--2023....................  EPA Standard                  81             142              82             146
                                 (CO2 Grams per
                                 Ton-Mile).
                                NHTSA Standard            7.9568         13.9489          8.0550         14.3418
                                 (Gallons per
                                 1,000 Ton-Mile).
2024--2026....................  EPA Standard                  79             141              81             144
                                 (CO2 Grams per
                                 Ton-Mile).
                                NHTSA Standard            7.7603         13.8507          7.9568         14.1454
                                 (Gallons per
                                 1,000 Ton-Mile).
2027 +........................  EPA Standard                  77             140              80             144
                                 (CO2 Grams per
                                 Ton-Mile).
                                NHTSA Standard            7.5639         13.7525          7.8585         14.1454
                                 (Gallons per
                                 1,000 Ton-Mile).
----------------------------------------------------------------------------------------------------------------

    It should be noted that the proposed standards are based on highway 
cruise cycles that include road grade to better reflect real world 
driving and to help recognize engine and driveline technologies. See 
Section III.E. The agencies have evaluated some alternate road grade 
profiles recommended by the National Renewable Energy Laboratory (NREL) 
and have prepared possible alternative trailer vehicle standards based 
on these profiles. The agencies request comment on this analysis, which 
is available in a memorandum to the docket.\240\
---------------------------------------------------------------------------

    \240\ Memorandum dated May 2015 on Analysis of Possible Tractor, 
Trailer, and Vocational Vehicle Standards Based on Alternative Road 
Grade Profiles. Docket EPA-HQ-OAR-2014-0827.
---------------------------------------------------------------------------

(f) Technology Costs for the Proposed Standards
    The agencies evaluated the technology costs for 53-foot dry and 
refrigerated vans and 28-foot dry vans, which we believe are 
representative of the majority of trailers in the 50-foot and longer 
and shorter than 50-foot categories, respectively. We identified costs 
for each technology package evaluated and projected the costs for each 
year of the program. A summary of the technology costs is included in 
Table IV-17 through Table IV-20 for MYs 2018 through 2027, with 
additional details available in the draft RIA Chapter 2.12. Costs shown 
in the following tables are for the specific model year indicated and 
are incremental to the average reference case costs, which includes 
some level of adoption of these technologies as shown in Table IV-13. 
Therefore, the technology costs in the following tables reflect the 
average cost expected for each of the indicated trailer classes. Note 
that these costs do not represent actual costs for the individual 
components because some fraction of the component costs has been 
subtracted to reflect some use of these components in the reference 
case. For more on the estimated technology costs exclusive of adoption 
rates, refer to Chapter 2.12 of the draft RIA. These costs include 
indirect costs via markups and reflect lower costs over time due to 
learning impacts. For a description of the markups and learning impacts 
considered in this analysis and how technology costs for other years 
are thereby affected, refer to Chapter 7 of the draft RIA. We welcome 
comment on the technology costs, markups, and learning impacts.

                    Table IV-17--Trailer Technology Incremental Costs in the 2018 Model Year
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                   53-foot  dry    refrigerated    28-foot  dry     Non-aero  &
                                                        van             van             van           non-box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................            $285            $285              $0              $0
Tires...........................................              65              65              78             185
Tire inflation system...........................             239             239             435             683
                                                 ---------------------------------------------------------------
    Total.......................................             588             588             514             868
----------------------------------------------------------------------------------------------------------------


[[Page 40272]]


                    Table IV-18--Trailer Technology Incremental Costs in the 2021 Model Year
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                   53-foot  dry    refrigerated    28-foot  dry     Non-aero  &
                                                        van             van             van           non-box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................            $602            $602            $468              $0
Tires...........................................              65              65              79             175
Tire inflation system...........................             234             234             426             632
                                                 ---------------------------------------------------------------
    Total.......................................             901             901             974             807
----------------------------------------------------------------------------------------------------------------


                    Table IV-19--Trailer Technology Incremental Costs in the 2024 Model Year
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                   53-foot  dry    refrigerated    28-foot  dry     Non-aero  &
                                                        van             van             van           non-box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................            $836            $836            $608              $0
Tires...........................................              61              61              76             160
Tire inflation system...........................             220             220             412             578
                                                 ---------------------------------------------------------------
    Total.......................................           1,116           1,116           1,097             739
----------------------------------------------------------------------------------------------------------------


                    Table IV-20--Trailer Technology Incremental Costs in the 2027 Model Year
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                   53-foot  dry    refrigerated    28-foot  dry     Non-aero  &
                                                        van             van             van           non-box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................          $1,163          $1,034            $788              $0
Tires...........................................              54              54              74             155
Tire inflation system...........................             192             192             391             549
                                                 ---------------------------------------------------------------
    Total.......................................           1,409           1,280           1,253             704
----------------------------------------------------------------------------------------------------------------

(4) Consistency of the Proposed Trailer Standards With the Agencies' 
Legal Authority
    The agencies' initial determination, subject to consideration of 
public comment, is that the standards presented in the Section IV.C.2, 
are the maximum feasible and appropriate under the agencies' respective 
authorities, considering lead time, cost, and other factors. The 
agencies' proposed decisions on the stringency and timing of the 
proposed standards focused on available technology and the consequent 
emission reductions and fuel efficiency improvements associated with 
use of the technology, while taking into account the circumstances of 
the trailer manufacturing sector. Trailer manufacturers would be 
subject to first-time emission control and fuel consumption regulation 
under the proposed standards. These manufacturers are in many cases 
small businesses, with limited resources to master the mechanics of 
regulatory compliance. Thus, the agencies' proposal seeks to provide a 
reasonable time for trailer manufacturers to become familiar with the 
requirements and the proposed new compliance regime, given the unique 
circumstances of the industry and the compliance flexibilities and 
optional compliance mechanisms specially adapted for this industry 
segment that we are proposing.
    The stringency of the standard is predicated on more widespread 
deployment of aerodynamic and tire technologies that are already in 
commercial use. The availability, feasibility, and level of 
effectiveness of these technologies are well-documented. Thus the 
agencies do not believe that there is any issue of technological 
feasibility of the proposed standards. Among the issues reflected in 
the agencies' proposal are considerations of cost and sufficiency of 
lead-time--including lead-time not only to deploy technological 
improvements, but also this industry sector to assimilate for the first 
time the compliance mechanisms of the proposed rule.
    The highest cost shown in Table IV-20 is associated with the long 
dry vans. We project that the average cost per trailer to meet the 
proposed MY 2027 standards for these trailers would be about $1,400, 
which is less than 10 percent of the cost of a new dry van trailer 
(estimated to be about $20,000). Other trailer types have lower 
projected technology costs, and many have higher purchase prices. As a 
result, we project that the per-trailer costs for all trailers covered 
in this regulation will be less than 10 percent of the cost of a new 
trailer. This trend is consistent with the expected average control 
costs for Phase 2 tractors, which are also less than 10 percent of 
typical tractor costs (see Section III).
    The agencies believe these technologies can be adopted at the rates 
the standards are predicated on within the proposed lead-time, as 
discussed above in Section IV.C.(3). Moreover, we project that most 
owners would rapidly recover the initial cost of these technologies due 
to the associated fuel savings, usually in less than two years, as 
shown in the payback analysis in Section IX. This payback period is 
generally considered reasonable in the

[[Page 40273]]

trailer industry for investments that reduce fuel consumption.\241\
---------------------------------------------------------------------------

    \241\ Roeth, Mike, et al. ``Barriers to Increased Adoption of 
Fuel Efficiency Technologies in Freight Trucking''. July 2013. 
International Council for Clean Transportation. Available here: 
http://www.theicct.org/sites/default/files/publications/ICCT-NACFE-CSS_Barriers_Report_Final_20130722.pdf.
---------------------------------------------------------------------------

    Overall, as discussed above in IV.D.3.c in the context of our 
assumed technology adoption rates, the gradual increase in stringency 
of the proposed trailer program over the phase-in period recognizes two 
important factors that the agencies carefully considered in developing 
this proposed rule. One factor is that assumed adoption of technologies 
many of the aerodynamic technologies that box trailer manufacturers 
would likely choose are available today and clearly technologically 
feasible throughout the phase-period. At the same time, we recognize 
that the adoption of these technologies across the industry scale 
envisioned by the proposed program would likely take time. The 
standards we are proposing in the interim years represent steady 
improvement in average aerodynamic performance toward the final MY 2027 
standards.

E. Alternative Standards and Feasibility Considered

    As discussed in Section X, the agencies evaluated several different 
regulatory alternatives representing different levels of stringency for 
the Phase 2 program. The results of the analysis of these proposed 
alternatives are discussed below in Section X of the preamble. The 
agencies believe each alternative is feasible from a technical 
standpoint. However, each successive alternative increases costs and 
complexity of compliance for the manufacturers, which can be a 
prohibitive burden on the large number of small businesses in the 
industry. Table IV-21 provides a summary of the alternatives considered 
in this proposal.

    Table IV-21--Summary of Alternatives Considered for the Proposed
                               Rulemaking
------------------------------------------------------------------------
 
------------------------------------------------------------------------
Alternative 1........................  No action alternative.
Alternative 2........................  Expand the use of aerodynamic and
                                        tire technologies at SmartWay
                                        levels to all 53-foot box
                                        trailers.
Alternative 3 (Proposed Alternative).  Adoption of advanced aerodynamic
                                        and tire technologies on all box
                                        trailers.
                                       Adoption of tire technologies on
                                        non-box trailers.
Alternative 4........................  Same technology and application
                                        assumptions as Alternative 3
                                        with an accelerated introduction
                                        schedule.
Alternative 5........................  Aggressive adoption of advance
                                        aerodynamic and tire
                                        technologies for all box
                                        trailers.
                                       Adoption of aerodynamic and tire
                                        technologies for some tank,
                                        flatbed, and container chassis
                                        trailers.
                                       Adoption of tire technologies for
                                        the remaining non-box trailers.
------------------------------------------------------------------------

    While we welcome comment on any of these alternatives, we are 
specifically requesting comment on Alternative 4 for the trailer 
program identified as Alternative 4 above and in Section X. The same 
general technology effectiveness values were considered and much of the 
feasibility analysis was the same in this alternative and in the 
proposed alternative, but Alternative 4 applies the adoption rates of 
higher-performing aerodynamic technologies from Alternative 3 at 
earlier stages for box trailers. This accelerated alternative achieves 
the same final fuel consumption and CO2 reductions as our 
proposed alternative three years in advance. The following sections 
detail the adoption rates, reductions and costs projected for this 
alternative.
(1) Effectiveness, Adoption Rates, and Technology Costs for Alternative 
4
    Alternative 4 includes the same trailer subcategories and same 
trailer technologies as the proposed alternative. Therefore, the zero-
technology baseline trailers (Table IV-7), reference case trailers 
(Table IV-10) and performance levels (Table IV-8) described in Section 
IV. D. apply for this analysis as well. The following sections describe 
the adoption rates of this accelerated alternative and the associated 
benefits and costs.
(a) Projected Technology Adoption Rates for Alternative 4
    The adoption rates and average performance parameters projected by 
the agencies for Alternative 4 are shown in Table IV-22 and Table IV-
23. Adoption rates for non-aero box and non-box trailers remain 
unchanged from the proposed standards and they are not repeated in this 
section. From the tables, it can be seen that the 2018 MY aerodynamic 
technology adoption rates and the tire technology adoption rates for 
all model years are identical to those presented previously for the 
proposed standards. The aerodynamic projections for MY 2021 and MY 2024 
in this accelerated alternative are the same as those projected for MY 
2024 and MY 2027 of the proposed standards, but are applied three years 
earlier. In this alternative, the 2021 MY adoption rates would continue 
to apply for the partial-aero box trailers in 2024 and later model 
years.

                        Table IV-22--Adoption Rates and Average Performance Parameters for the Long Box Trailers in Alternative 4
--------------------------------------------------------------------------------------------------------------------------------------------------------
                       Technology                                        Long box dry vans                          Long box refrigerated vans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                       Model year                              2018            2021            2024            2018            2021            2024
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aerodynamic Technologies: \a\
    Bin I...............................................              5%  ..............  ..............              5%  ..............  ..............
    Bin II..............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin III.............................................             30%  ..............  ..............             30%  ..............  ..............
    Bin IV..............................................             60%             25%  ..............             60%             25%  ..............
    Bin V...............................................              5%             10%             10%              5%             10%             20%
    Bin VI..............................................  ..............             65%             50%  ..............             65%             60%

[[Page 40274]]

 
    Bin VII.............................................  ..............  ..............             40%  ..............  ..............             20%
    Bin VIII............................................  ..............  ..............  ..............  ..............  ..............  ..............
        Average Delta CDA (m2) a........................             0.4             0.8             1.1             0.4             0.8             1.0
Trailer Tire Rolling Resistance:
    Baseline tires......................................              15               5               5              15               5               5
    Level 1 tires.......................................              85              95  ..............              85              95  ..............
    Level 2 tires.......................................  ..............  ..............              95  ..............  ..............              95
        Average CRR (kg/ton) a..........................             5.2             5.1             4.8             5.2             5.1             4.8
Tire Inflation System:
    ATI.................................................             85%             95%             95%             85%             95%             95%
        Average ATI Reduction (%)a......................            1.3%            1.4%            1.4%            1.3%            1.4%            1.4%
Weight Reduction (lbs):
    Weight b............................................  ..............  ..............  ..............  ..............  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
a Combines adoption rates with performance levels shown in Table IV-8.
b This set of adoption rates did not apply weight reduction to meet the proposed standards for these trailers.


                       Table IV-23--Adoption Rates and Average Performance Parameters for the Short Box Trailers in Alternative 4
--------------------------------------------------------------------------------------------------------------------------------------------------------
                       Technology                                       Short box dry vans                          Short box refrigerated vans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                       Model Year                              2018            2021            2024            2018            2021            2024
--------------------------------------------------------------------------------------------------------------------------------------------------------
Aerodynamic Technologies a
    Bin I...............................................            100%  ..............  ..............            100%  ..............  ..............
    Bin II..............................................  ..............             70%             30%  ..............             70%             55%
    Bin III.............................................  ..............             30%             60%  ..............             30%             40%
    Bin IV..............................................  ..............  ..............             10%  ..............  ..............              5%
    Bin V...............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin VI..............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin VII.............................................  ..............  ..............  ..............  ..............  ..............  ..............
    Bin VIII............................................  ..............  ..............  ..............  ..............  ..............  ..............
        Average Delta CDA (m2) b........................             0.4             0.8             1.1             0.4             0.8             1.0
Trailer Tire Rolling Resistance:
    Baseline tires......................................             15%              5%              5%             15%              5%              5%
    Level 1 tires.......................................             85%             95%  ..............             85%             95%  ..............
    Level 2 tires.......................................  ..............  ..............             95%  ..............  ..............             95%
        Average CRR (kg/ton) b..........................             5.2             5.1             4.8             5.2             5.1             4.8
Tire Inflation System:
    ATI.................................................             85%             95%             95%             85%             95%             95%
        Average ATI Reduction (%) b.....................            1.3%            1.4%            1.4%            1.3%            1.4%            1.4%
Weight Reduction (lbs):
    Weight c............................................  ..............  ..............  ..............  ..............  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: A blank cell indicates a zero value.
a The majority of short box trailers are 28 feet in length. We recognize that they are often operated in tandem, which limits the technologies that can
  be applied (for example, boat tails).
b Combines adoption rates with performance levels shown in Table IV-8.
c This set of adoption rates did not apply weight reduction to meet the proposed standards for these trailers.

(b) Derivation of the Standards for Alternative 4
    Similar to the proposed standards of Section IV. D. (3) (d), the 
agencies applied the technology performance values from Table IV-22 and 
Table IV-23 as GEM inputs to derive the proposed standards for each 
subcategory.
    Table IV-24 shows the resulting standards for Alternative 4. Over 
the three phases of the alternative, box trailers longer than 50 feet 
would, on average, reduce their CO2 emissions and fuel 
consumption by two percent, six percent and eight percent. Box trailers 
50-foot and shorter would achieve reductions of two percent, three 
percent, and four percent compared to the reference case. Partial-aero 
box trailers would continue to be subject to the 2021 MY standards for 
MY 2024 and later. The non-aero box and non-box trailers would meet the 
same standards as shown in the proposed Alternative 3 and achieve the 
same two and three percent benefits as shown in the proposed 
alternative.

[[Page 40275]]



            Table IV-24--Trailer CO2 and Fuel Consumption Standards for Box Trailers in Alternative 4
----------------------------------------------------------------------------------------------------------------
                                   Subcategory                Dry van                    Refrigerated van
          Model year           ---------------------------------------------------------------------------------
                                     Length            Long            Short           Long            Short
----------------------------------------------------------------------------------------------------------------
2018-2020.....................  EPA Standard....              83             144              84             147
                                (CO2 Grams per
                                 Ton-Mile).
                                Voluntary NHTSA           8.1532         14.1454          8.2515         14.4401
                                 Standard.
                                (Gallons per
                                 1,000 Ton-Mile).
2021-2023.....................  EPA Standard....              80             142              81             145
                                (CO2 Grams per
                                 Ton-Mile).
                                NHTSA Standard..          7.8585         13.9489          7.9568         14.2436
                                (Gallons per
                                 1,000 Ton-Mile).
2024+.........................  EPA Standard....              77             140              80             144
                                (CO2 Grams per
                                 Ton-Mile).
                                NHTSA Standard..          7.5639         13.7525          7.8585         14.1454
                                (Gallons per
                                 1,000 Ton-Mile).
----------------------------------------------------------------------------------------------------------------

(c) Costs Associated With Alternative 4
    A summary of the technology costs is included in Table IV-25 to 
Table IV-27for MYs 2018, 2021 and 2024, with additional details 
available in the draft RIA Chapter 2.12. Costs shown in the following 
tables are for the specific model year indicated and are incremental to 
the average reference case costs, which includes some level of adoption 
of these technologies as shown in Table IV-10. Therefore, the 
technology costs in the following tables reflect the average cost 
expected for each of the indicated trailer classes. Note that these 
costs do not represent actual costs for the individual components 
because some fraction of the component costs has been subtracted to 
reflect some use of these components in the reference case. For more on 
the estimated technology costs exclusive of adoption rates, refer to 
Chapter 2.12 of the draft RIA. These costs include indirect costs via 
markups and reflect lower costs over time due to learning impacts. For 
a description of the markups and learning impacts considered in this 
analysis and how it impacts technology costs for other years, refer to 
the draft RIA.

           Table IV-25--Trailer Technology Incremental Costs in the 2018 Model Year for Alternative 4
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                    53-foot dry    refrigerated     28-foot dry   Non-aero & non-
                                                        van             van             van             box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................            $285            $285              $0              $0
Tires...........................................              65              65              78             185
Tire inflation system...........................             239             239             435             683
                                                 ---------------------------------------------------------------
    Total.......................................             588             588             514             868
----------------------------------------------------------------------------------------------------------------


           Table IV-26--Trailer Technology Incremental Costs in the 2021 Model Year for Alternative 4
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                    53-foot dry    refrigerated     28-foot dry   Non-aero & non-
                                                        van             van             van             box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................            $908            $908            $641              $0
Tires...........................................              65              65              79             175
Tire inflation system...........................             234             234             426             632
                                                 ---------------------------------------------------------------
    Total.......................................           1,207           1,207           1,146             807
----------------------------------------------------------------------------------------------------------------


           Table IV-27--Trailer Technology Incremental Costs in the 2024 Model Year for Alternative 4
                                                     [2012$]
----------------------------------------------------------------------------------------------------------------
                                                                      53-foot
                                                    53-foot dry    refrigerated     28-foot dry   Non-aero & non-
                                                        van             van             van             box
----------------------------------------------------------------------------------------------------------------
Aerodynamics....................................           1,223           1,090             816               0
Tires...........................................              61              61              76             160
Tire inflation system...........................             220             220             412             578
                                                 -----