[Federal Register Volume 64, Number 209 (Friday, October 29, 1999)]
[Proposed Rules]
[Pages 58472-58566]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-26795]



[[Page 58471]]

_______________________________________________________________________

Part II





Environmental Protection Agency





_______________________________________________________________________



40 CFR Parts 85 and 86



Control of Emissions of Air Pollution From 2004 and Later Model Year 
Heavy-Duty Highway Engines and Vehicles; Revision of Light-Duty Truck 
Definition; Proposed Rule

  Federal Register / Vol. 64, No. 209 / Friday, October 29, 1999 / 
Proposed Rules  

[[Page 58472]]



ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 85 and 86

[AMS-FRL-6456-3]
RIN 2060-AI12, 2060-AI23


Control of Emissions of Air Pollution From 2004 and Later Model 
Year Heavy-Duty Highway Engines and Vehicles; Revision of Light-Duty 
Truck Definition

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We are proposing to take several actions relating to emission 
standards and test procedures for heavy-duty engines and vehicles 
intended for operation on roads and highways. The proposed provisions 
are for the 2004 and later model years. First, we are proposing new 
more stringent emissions standards and related provisions for all 
heavy-duty Otto-cycle (e.g., gasoline-fueled) engines and vehicles. 
Vehicles in this category include large full size pick-up trucks, full 
size cargo and passenger vans, and the largest sport utility vehicles. 
For heavy-duty Otto-cycle engines and vehicles, today's proposal would 
reduce the standards for oxides of nitrogen and hydrocarbons by 
approximately 75 percent from current standards. Second, we propose to 
reaffirm that the NMHC+NOX standard promulgated in October, 
1997 for diesel heavy-duty engines is both necessary and feasible. This 
standard represents about a 50 percent reduction in emissions of 
nitrogen oxides, as well as reductions in hydrocarbons, from diesel 
trucks and buses. Third, we are proposing to require on-board 
diagnostics systems for all heavy-duty vehicles and engines at or below 
14,000 lbs gross vehicle weight rating (GVWR), and to revise the on-
board diagnostics requirements for diesel light-duty vehicles and 
trucks. These systems will identify the failure of components of the 
emissions control system. Fourth, we are proposing the addition of new 
test procedures and associated standards for heavy-duty diesel engines 
and vehicles. Fifth, we are proposing to include heavy models of 
gasoline and diesel-fueled sport-utility vehicles and similar heavy-
duty vehicles used primarily for personal transportation in the Tier 2 
program that EPA proposed earlier this year. Today's proposal would 
result in lower emissions of oxides of nitrogen and hydrocarbons, as 
well as lower particulate matter due to reductions in secondary 
particulate formation (secondary particulate matter is not emitted 
directly from the engine, but is formed when emissions of oxides of 
nitrogen react with ammonia in the atmosphere to produce ammonium 
nitrate particulates), and would assist states and regions facing ozone 
air quality problems that are causing a range of adverse health 
effects, particularly respiratory impairment and related illnesses.

DATES: We must receive your comments on this NPRM by December 2, 1999. 
A public hearing will be held on November 2, 1999 (EPA has published 
notice of this hearing on October 22, 1999 (64 FR 56985).). EPA 
requests that parties who want to testify notify the contact person 
listed in the ADDRESSES section of this document one week before the 
date of the hearing. More information about commenting on this action 
and on the public hearing may be found in section XI What are the 
Opportunities for Public Participation?

ADDRESSES: Written comments should be submitted (in duplicate, if 
possible) to: EPA Air and Radiation Docket, Attn: Docket No. A-98-32, 
Room M-1500 (Mail Code 6102), 401 M Street SW, Washington, DC 20460. 
EPA requests that a copy of the comments also be sent to the contact 
person listed below. Materials relevant to this proposal have been 
placed in Docket Nos. A-98-32 and A-95-27 and may be viewed in Room M-
1500 between 8:00 a.m. and 5:30 p.m., Monday through Friday. The 
telephone number is (202) 260-7548 and the facsimile number is (202) 
260-4400. A reasonable fee may be charged by EPA for copying docket 
materials.
    The public hearing will be held at Top of the Tower, 1717 Arch 
Street, 51st Floor, Philadelphia, PA 19103, telephone: 215-567-8787, 
fax: 215-557-5171.

FOR FURTHER INFORMATION CONTACT: Margaret Borushko, U.S. Environmental 
Protection Agency, Engine Programs and Compliance Division, 2000 
Traverwood Drive, Ann Arbor, MI 48105-2498. Telephone (734) 214-4334; 
Fax (734) 214-4816; e-mail [email protected].

SUPPLEMENTARY INFORMATION:

Regulated Entities

    Entities potentially regulated by this action are those that 
manufacture and sell new heavy-duty motor vehicles, new heavy-duty 
engines, and new diesel light-duty motor vehicles in the United States. 
Regulated categories and entities include:

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                Category                 Examples of regulated  entities
------------------------------------------------------------------------
Industry...............................  Manufacturers of new heavy-duty
                                          motor vehicles and engines.
                                         Manufacturers of new diesel
                                          light-duty motor vehicles and
                                          engines.
------------------------------------------------------------------------

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. This table lists the types of entities that EPA is now aware 
could potentially 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 Secs. 86.001-1 and 86.1801-01. If 
you have questions regarding the applicability of this action to a 
particular entity, consult the person listed in the preceding FOR 
FURTHER INFORMATION CONTACT section.

Obtaining Rulemaking Documents Through the Internet

    The preamble, regulatory language, regulatory impact analysis, and 
other related documents are also available electronically from the EPA 
Internet Web site. This service is free of charge, except for any cost 
you already incur for Internet connectivity. The electronic version is 
made available on the day of publication on the primary Web site listed 
below. The EPA Office of Mobile Sources also publishes Federal Register 
notices and related documents on the secondary Web site listed below.

1. http://www.epa.gov/docs/fedrgstr/EPA-AIR/ (either select desired 
date or use Search feature)
2. http://www.epa.gov/OMSWWW/ (Look in What's New or under the specific 
rulemaking topic)

    Please note that due to differences between the software used to 
develop the document and the software into which the document may be 
downloaded, changes in format, page length, etc. may occur.

                   Table of Acronyms and Abbreviations
------------------------------------------------------------------------
 
------------------------------------------------------------------------
ABT                      Averaging, Banking, and Trading
AECD                     Auxiliary Emission Control Device
ALVW                     Adjusted Loaded Vehicle Weight
ANPRM                    Advance Notice of Proposed Rulemaking
BSFC                     Brake-Specific Fuel Consumption
CAA                      Clean Air Act
CAP 2000                 Compliance Assurance Program for the 2000 and
                          later model years
CARB                     California Air Resources Board

[[Page 58473]]

 
CASAC                    Clean Air Scientific Advisory Committee
CFF                      Clean Fuel Fleet
CO                       Carbon Monoxide
DF                       Deterioration Factor
DOC                      Diesel Oxidation Catalyst
DRI                      Desert Research Institute
EGR                      Exhaust Gas Recirculation
EMA                      Engine Manufacturers Association
EPA                      Environmental Protection Agency
FEL                      Family Emission Limit
g/bhp-hr                 grams per brake-horsepower hour
g/mi                     grams per mile
GVWR                     Gross Vehicle Weight Rating
HC                       Hydrocarbons
HD                       Heavy-Duty
HDDE                     Heavy-Duty Diesel Engine
HDE                      Heavy-Duty Engine
HDEWG                    Heavy-Duty Engine Working Group
HDV                      Heavy-Duty Vehicle
HEUI                     Hydraulically Actuated Electronic Unit
                          Injection
HLDT                     Heavy Light-Duty Truck
LDT                      Light-Duty Truck
LDV                      Light-Duty Vehicle
LEV                      Low Emission Vehicle
LLDT                     Light Light-Duty Truck
LRT                      Load Response Test
MDV                      Medium-Duty Vehicle
MEUI                     Mechanically Actuated Electronic Unit Injection
MIL                      Malfunction Indicator Light
MY                       Model Year
NAAQS                    National Ambient Air Quality Standards
NCP                      Non-Conformance Penalty
NMHC                     Non-Methane Hydrocarbon
NMOG                     Non-Methane Organic Gas
NOX                      Nitrogen Oxides
NPRM                     Notice of Proposed Rulemaking
OBD                      On-Board Diagnostics
OEM                      Original Equipment Manufacturer
ORVR                     Onboard Refueling Vapor Recovery
PM                       Particulate Matter
PM10                     Particulate Matter of 10 microns or less in
                          diameter
PM2.5                    Particulate Matter of 2.5 microns or less in
                          diameter
RIA                      Regulatory Impact Analysis
SIP                      State Implementation Plan
SOP                      Statement of Principles
TW                       Test Weight
UDDS                     Urban Dynamometer Driving Schedule
ULEV                     Ultra Low Emission Vehicle
VGT                      Variable Geometry Turbocharger
VMT                      Vehicle Miles Traveled
VNT                      Variable Nozzle Turbocharger
VOC                      Volatile Organic Compound
------------------------------------------------------------------------

Table of Contents

I. What is EPA Proposing to Do?

A. Changes to the Engine-Based Program
B. Expanding the Otto-cycle Vehicle-based Program to Certain Heavy-
duty Vehicles
C. Additional Changes Affecting Heavy-duty Vehicle and Heavy-duty 
Engine Programs
D. Heavy-duty Lead Time Issues and Voluntary Federal Standards

II. What is the Environmental Need for this Proposal?

A. Need for Additional NOX and NMHC Reductions
    1. Health and Welfare Effects from NMHC and NOX
    2. Current Compliance with the Ozone NAAQS
    3. Future Compliance with the Ozone NAAQS
    4. Contribution of HD Diesel and Gasoline Engines to Total VOC 
and NOX Inventories
B. Need for Additional PM Reductions
    1. Health and Welfare Effects from PM
    2. Current and Future Compliance with the PM10 NAAQS
    3. Contribution of HD Diesel and Gasoline Vehicles to PM 
Inventories
    a. Contribution to National PM10 Inventories
    b. Source-apportionment Studies for Diesel PM
C. Air Toxics from HD Engines and Vehicles

III. What is the Important Background Information for this Proposal?

A. Statement of Principles and Rulemaking History
B. 1999 Review of Heavy-duty Diesel Engine NMHC+NOX 
Standards
C. Proposal for Heavy-duty Gasoline Engine Standards
    1. Summary of Comments on 1996 NPRM
    2. Analysis Leading to Decision to not Finalize Otto-cycle 
Standards
D. Consent Decrees with Heavy-duty Diesel Engine Manufacturers

IV. What are the Details of this Proposal?

A. Reaffirmation of 2004 NMHC + NOX Standard for Heavy-
duty Diesel Engines
B. Are Changes in Diesel Fuel Quality Necessary to Meet the 2004 
Standards?
C. Otto-cycle Engine-based Program
    1. Engine Exhaust Emissions Standards
    2. Averaging, Banking, and Trading for Otto-Cycle Engines
D. Supplemental Exhaust Emission Standards and Test Procedures for 
HD Diesel Engines
    1. Introduction/Background
    2. Proposed Supplemental Test Procedures and Standards
    a. Supplemental Steady-State Test
    b. Not-To-Exceed Limits
    c. Diesel Supplemental Load Response Test
    d. Ambient Conditions, Temperature and Humidity, Laboratory and 
In-use Testing
    3. Access to On-board Computer Information
E. Otto-cycle Vehicle-based Program
    1. Moving to a Vehicle-based Test Procedure and Standards
    2. Vehicle Exhaust Emissions Standards
    3. Heavy-duty Vehicle Averaging, Banking and Trading
    a. Background
    b. Proposal
    c. Credit exchanges between the engine and chassis-based 
programs
    4. Evaporative standards/onboard refueling vapor recovery
    a. Enhanced evaporative emissions
    b. Onboard refueling vapor recovery
    5. Compliance Assurance Program
    a. CAP 2000 for HDVs
    b. Proposed Modifications to the CAP 2000 Program For Chassis-
Based HDVs
    6. Useful Life
    7. Aftermarket Alternative Fuels Conversions
F. Proposal to Revise the Definition of Light-duty Truck
    1. Background
    2. Proposal
    3. Integration into Proposed Tier 2 Program
    a. Tier 2 Standards for New HLDTs
    b. Interim Standards for New HLDTs
    c. Technological Feasibility of Tier 2 Standards for New HLDTs
G. On-Board Diagnostics
    1. Background on OBD
    2. CARB OBDII Requirements
    3. Proposed Federal OBD Requirements
    4. Federal OBD Malfunction Thresholds and Monitoring 
Requirements
    5. Proposed Standardization Requirements
    6. Deficiency Provisions
    7. Applicability and Waivers
    8. Certification Provisions
H. Durability Procedures
I. Non-Conformance Penalties

V. Additional Heavy-Duty Engine Provisions Under Consideration

A. Revision to the Definition of Rated Speed
B. A Manufacturer-based In-use Testing Program for Heavy-duty 
Engines
C. On-board Diagnostics for Heavy-duty Engines and Vehicles Above 
14,000 Pounds GVWR
D. Applying the Not-to-Exceed Approach and Emission Limits to Heavy-
duty Otto-cycle Engines

VI. Are the Proposed Requirements Technologically Feasible?

A. 2004 Emission Standards for Heavy-duty Diesel Engines
    1. Probable Emission Control Strategies
    2. Feasibility of 2004 HD Diesel Standards
B. 2004 Emission Standards for Heavy-duty Otto-cycle Vehicles and 
Engines
    1. Current Technologies
    2. Chassis-based standards
    3. Engine-based standards
    4. Onboard Refueling Vapor Recovery
C. On-Board Diagnostics

VII. What are the Environmental Benefits of this Proposal?

A. 2004 Emission Standards for Heavy-Duty Diesel Engines
B. 2004 Emission Standards for Heavy-duty Otto-cycle Vehicles and 
Engines
C. Benefits of the Supplemental Standards and In-Use Control 
Measures of Today's Proposal

VIII. What are the Economic Impacts of the Proposal?

A. 2004 Emission Standards for Heavy-duty Diesel Engines
    1. Expected Technologies
    2. Per Engine Costs
    3. Aggregate Costs to Society
B. 2004 Emission Standards for Heavy-duty Otto-cycle Vehicles and 
Engines
    1. Expected Technologies
    2. Per Vehicle Costs
    3. Aggregate Cost to Society

[[Page 58474]]

IX. What is the Cost-Effectiveness of the Proposal?

A. 2004 Emission Standards for Heavy-duty Diesel Engines
B. 2004 Emission Standards for Heavy-duty Otto-cycle Vehicles and 
Engines

X. Are Future Reductions in HD Emissions Possible?

A. Potential Future Standards for Heavy-duty Diesel Vehicles and 
Engines
    1. Potential Future Reductions in Heavy-duty Diesel 
NOX and NMHC
    2. Potential Future Reductions in Heavy-duty Diesel Engine PM
    3. Potential Structure of Future Diesel Emission Standards
B. Potential Future Standards for Heavy-duty Otto-cycle Vehicles
    1. Exhaust Emission Standards
    2. Evaporative standards

XI. What are the Opportunities for Public Participation?

A. Comments and the Public Docket
B. Public Hearing

XII. What Administrative Requirements Apply to this Proposal?

A. Compliance with Executive Order 12866
B. Impact on Small Entities
C. Unfunded Mandates Reform Act
D. Reporting and Recordkeeping Requirements
E. Compliance with Executive Order 13045
F. Enhancing Intergovernmental Partnerships
G. Consultation and Coordination with Indian Tribal Governments
H. National Technology Transfer and Advancement Act
I. Compliance with Executive Order on Federalism

XIII. What is EPA's Statutory Authority for this Proposal?

I. What Is EPA Proposing To Do?

    EPA (or, ``the Agency'') is proposing to take several actions 
relating to emission standards and test procedures for heavy-duty 
engines (HDEs) and heavy-duty vehicles (HDVs) intended for highway 
operation.\1\ The proposed provisions would become effective starting 
with the 2004 model year (MY). These actions supplement a June 1996 
proposed rule (61 FR 33421, June 27, 1996), in which we proposed new 
emission standards for heavy-duty diesel engines (HDDE) and heavy-duty 
Otto-cycle engines and vehicles, and a subsequent October 1997 final 
rule (62 FR 54694, October 21, 1997), in which we finalized new 
emission standards for heavy-duty diesel engines.\2\
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    \1\ Light-duty vehicles and light-duty trucks are defined as 
vehicles with a gross vehicle weight rating (GVWR) below 8,500 
pounds. Heavy-duty vehicles are vehicles with a GVWR greater than or 
equal to 8,500 pounds. Heavy-duty engines are engines used in heavy-
duty vehicles.
    \2\ The terms ``diesel'' and ``Otto-cycle'' generally refer to 
the type of combustion cycle employed by an engine. In a diesel-
cycle engine combustion is brought about by the compression of the 
fuel mixture (compression ignition), whereas in an Otto-cycle engine 
combustion is achieved by providing a spark to the fuel mixture 
(spark ignition). Although a generalization for which there are 
exceptions, diesel-cycle vehicles are generally fueled with diesel 
fuel and Otto-cycle vehicles are generally fueled with standard 
gasoline.
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    Currently, EPA has a chassis-based regulatory program for light-
duty vehicles (LDVs) and light-duty trucks (LDTs), meaning that the 
vehicle itself is subject to emission standards and testing. For all 
heavy-duty vehicles the engine alone is tested and must currently meet 
engine-based standards.\3\ Engine testing currently applies to all 
diesel-cycle and Otto-cycle heavy-duty vehicles. One of the key 
elements of today's action is a proposal to begin regulating a subset 
of heavy-duty vehicles using chassis-based requirements. The heavy-duty 
vehicles that are proposed to be subject to chassis-based requirements 
are complete Otto-cycle heavy-duty vehicles with a gross vehicle weight 
rating (GVWR) below 14,000 pounds.4,5 In addition, some 
complete gasoline and diesel-fueled heavy-duty vehicles between 8,500 
and 10,000 pounds GVWR are proposed to be incorporated into the Tier 2 
program proposed by EPA earlier this year (64 FR 26004, May 13, 1999). 
Today's proposal can generally be separated into those elements 
relating to the new chassis-based requirements and those elements that 
affect the engine-based requirements. The proposals listed below are 
explained in greater detail in the remainder of this document.
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    \3\ Engine-based standards are expressed in terms of emissions 
per unit of work, whereas chassis-based (or vehicle-based) standards 
are expressed in terms of amount of emissions per mile driven by the 
vehicle.
    \4\ ``Complete'' vehicles are those that are manufactured with 
their primary cargo carrying container or device attached, whereas 
``incomplete'' vehicles are those that are manufactured without the 
primary cargo carrying container or device attached. Incomplete 
vehicles (basically the engine plus a chassis) are then manufactured 
into a variety of vehicles, such as recreational vehicles, panel 
trucks, dump trucks, fire trucks, and tow trucks.
    \5\ Gross Vehicle Weight Rating (GVWR) is defined by federal 
regulation in 40 CFR 86.082-2 as ``The value specified by the 
manufacturer as the maximum design loaded weight of a single 
vehicle.'' In other words, it is the weight of the vehicle 
completely loaded with the maximum load that the manufacturer states 
the vehicle is capable of carrying.
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    Some of these proposals would harmonize EPA's regulatory programs 
with California's current medium-duty vehicle (MDV) program (e.g., 
vehicle-based standards for complete Otto-cycle heavy-duty vehicles 
below 14,000 pounds GVWR), while others may differ from California's 
current requirements. These similarities and differences are outlined 
in the detailed discussion that follows. We request comments on the 
proposals described below, and encourage commenters to supply relevant 
data that would help us further assess the proposals.6
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    \6\ The current federal standards for Clean Fuel Vehicles are 
less stringent than the proposed Otto-cycle standards and the 
existing diesel standards for the 2004 and later model years. See 40 
CFR 88.105-94. The 2004 and later model year standards proposed 
today would supercede the current Clean Fuel Vehicle standards, and, 
if EPA adopts the Otto-cycle standards proposed today and maintains 
the diesel standards for the 2004 and later model years, the Agency 
intends to undertake a rulemaking to revise the Clean Fuel Vehicle 
standards accordingly.
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A. Changes to the Engine-Based Program

    The first sections of this proposal describe the proposed revisions 
to the engine-based program. Some of these proposals would apply to 
both diesel and Otto-cycle engines, and others would apply uniquely to 
either diesel or Otto-cycle engines. Proposed requirements that affect 
the engine-based program include:
     Reaffirmation of the existing 2004 and later model year 
NMHC+NOx standard for heavy-duty diesel engines.
     New more stringent emission standards for 2004 and later 
model year Otto-cycle heavy-duty engines.
     A revised averaging, banking, and trading (ABT) program 
for Otto-cycle heavy-duty engines.
     Revised deterioration factor (DF) requirements for heavy-
duty engines.
     New emission standards for heavy-duty diesel engines to 
improve the assurance that vehicles are emitting low levels of 
pollutants over a wide range of operation experienced in actual use.
     New supplemental test procedures for heavy-duty diesel 
engines associated with the proposed new emission 
standards.7
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    \7\ We believe that our compliance program is fundamentally 
incomplete until a similar form of additional assurance that Otto-
cycle engines will meet applicable emission standards in-use can be 
added to the compliance requirements, but such provisions are not 
specifically proposed today. Section V of today's proposal describes 
several important compliance program elements that are not included 
in today's proposal, but that we intend to finalize such that they 
can take effect in conjunction with those elements in today's 
proposal. See section V for more information.
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B. Expanding the Otto-Cycle Vehicle-Based Program to Certain Heavy-Duty 
Vehicles

    Additional sections of this proposal describe the proposed chassis-
based (or vehicle-based) program for certain heavy-duty vehicles. Many 
of these proposals result in harmonization with the California Air 
Resources Board (CARB) Medium-duty Vehicle (MDV)

[[Page 58475]]

Program. For the vehicle-based program, we are proposing the following 
elements:
     New standards for 2004 and later model year complete Otto-
cycle heavy-duty vehicles with a GVWR below 14,000 pounds.
     The incorporation of certain complete Otto-cycle and 
diesel vehicles between 8,500 and 10,000 pounds GVWR into the Tier 2 
light-duty program. These provisions would be limited to those vehicles 
designed primarily for personal transportation.
     Vehicle-based testing of all complete heavy-duty Otto-
cycle vehicles below 14,000 pounds GVWR for these new standards.
     An averaging, banking, and trading program.
     On-board refueling vapor recovery (ORVR) requirements.
     CAP 2000 provisions.8
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    \8\ The new compliance assurance program for light-duty vehicles 
and light-duty trucks, known as CAP 2000 (since manufacturers may 
opt-in for model year 2000), streamlines the existing vehicle 
certification program, enabling manufacturers to save significant 
time and money. In addition, it requires manufacturers to test 
customer-owned in-use vehicles for model year 2001 and beyond. The 
CAP 2000 program was proposed on July 23, 1998 (63 FR 36954), and 
finalized on May 4, 1999 (64 FR 23906).
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     Revised useful life requirements.

C. Additional Changes Affecting Heavy-Duty Vehicle and Heavy-Duty 
Engine Programs

    Additional sections describe provisions or issues that apply to 
both heavy-duty vehicle and engine programs. These proposals include:
     On-board Diagnostics (OBD) requirements for heavy-duty 
diesel and Otto-cycle vehicles and engines up to 14,000 pounds GVWR.
     Non-Conformance Penalties (NCPs).

D. Heavy-Duty Lead Time Issues and Voluntary Federal Standards

    One of the important concepts contained in the rulemaking record, 
is the need for harmonized, 50-state emission standards for the heavy-
duty industry. Consistent national standards provide the states with 
the emission reductions they need, while providing manufacturers with 
the knowledge they can design and market one engine design regardless 
of what state the engine is sold to. Our proposal today would implement 
nationwide standards which would harmonize with California for the 
majority HD engines and vehicle in 2004 ( the exception being 
incomplete HD Otto-cycle engines.)
    Since the finalization of the 1997 rule for 2004 HD diesels, state 
and local air quality agencies have been counting on the emission 
reductions from the 2004 standards in order to meet their long-term air 
quality needs. In addition, as discussed previously in this proposal, 
the 2004 standards for HD Otto-cycle engines and vehicles will also 
provide state and local air quality agencies additional needed emission 
reductions. However, Section 202 of the Clean Air Act requires EPA to 
provide manufacturers of heavy-duty engines and vehicles four years of 
lead time between standards. This would require EPA to issue a final 
rule by the end of 1999 in order to implement new standards in 2004. We 
are concerned due to the short amount of time between today's proposal 
and the end of the calendar year that the final rule for today's 
proposal may not be final until after December 31, 1999, which may 
prevent a model year 2004 implementation of the standards proposed 
today. This concern does not apply for the 2004 model year heavy-duty 
diesel engine standards which were promulgated in 1997 and meet the 
lead time requirements.
    This four year lead time issue for the 2004 standards contained in 
today's proposal reflects a statutory requirement, not a technological 
feasibility issue. As demonstrated elsewhere in this proposal, 
technology is clearly available which will allow manufacturers to meet 
the proposed HD diesel and HD gasoline standards by 2004.
    The lack of more stringent federal 49-state HD standards in 2004 
may lead some states with incentive to exercise their rights under 
Section 177 of the Clean Air Act to adopt the California HD diesel and 
Otto-cycle standards in order to realize the emission reductions 
associated with covering vehicles produced in 2004. This could result 
in a patchwork of emission standards across the country and could 
present the manufacturers with significant difficulties.
    In the event the Agency is unable to finalize the new standards 
contained in today's proposal by the end of calendar year 1999, we 
request comment on the appropriateness of EPA's efforts to manage the 
implementation of these standards and in particular, of establishing a 
program for those manufacturers willing to cooperate in meeting the 
requirements in today's proposal. We would expect that manufacturers 
participating in this program would merely certify their 2004 model 
year engines to meet all of the emission standards and requirements 
included in today's proposal. If the proposed standards are not 
finalized by the end of 1999, mandatory federal standards would apply 
in model year 2005, with the goal of putting in place all requirements 
contained in today's proposal. We request comment on whether 
manufacturers would need to opt-in to such a program, and how such opt-
in would take place. In addition, EPA requests comment on incentives to 
encourage manufacturers to opt into the voluntary program.

II. What Is the Environmental Need for This Proposal?

    This section presents information on the negative health and 
environmental impacts from air pollution from heavy-duty (HD) engines 
and vehicles, as well as EPA's assessment of the need for additional 
emission reductions from HD engines and vehicles in order to meet the 
air quality needs of the U.S. A detailed analysis and explanation of 
the health impacts and air quality needs was presented in the advanced 
notice of proposed rulemaking, as well as the preamble and the 
Regulatory Impact Analysis (RIA) for the proposal and final rule of the 
1997 rulemaking for the 2004 standards.9 The reader should 
refer to those documents for additional information on this topic.
---------------------------------------------------------------------------

    \9\ See ``Control of Air Pollution for Heavy-Duty Engines, 
Advanced Notice of Proposed Rulemaking'', Available in EPA Air 
Docket A-95-27, Docket Item # AMS-FRL, and ``Draft Regulatory Impact 
Analysis: Control of Emissions of Air Pollution from Highway Heavy-
Duty Engines'', available in EPA Air Docket A-95-27, Docket Item # 
III-B-01, and ``Control of Emissions of Air Pollution from Highway 
Heavy-Duty Engines; Notice of Proposed Rulemaking'' available in EPA 
Air Docket A-95-27, Docket Item # III-A-01, and ``Final Regulatory 
Impact Analysis: Control of Emissions of Air Pollution from Highway 
Heavy-Duty Engines'', available in EPA Air Docket A-95-27, Docket 
Item # V-B-01, and ``Control of Emissions of Air Pollution from 
Highway Heavy-Duty Engines; Final Rule,'' available in EPA Air 
Docket A-95-27, Docket Item # V-A-01.
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A. Need for Additional NOx and NMHC Reductions

1. Health and Welfare Effects From NMHC and NOx
    Oxides of Nitrogen (NOx) and volatile organic compounds 
(VOC) are precursors in the photochemical reaction which forms 
tropospheric ozone. VOC emissions from mobile sources consist mostly of 
nonmethane hydrocarbons (NMHC). There is a large body of evidence 
showing that ozone can cause harmful respiratory effects including 
chest pain, coughing, and shortness of breath, affecting people with 
compromised respiratory systems and children most severely. In 
addition, NOx itself can directly harm human health. Beyond 
their human health effects, other negative environmental effects are 
also associated with ozone

[[Page 58476]]

and NOx. Ozone has been shown to injure plants and 
materials; NOx contributes to the secondary formation of 
particulate matter (PM) (nitrates), acid deposition, and the overgrowth 
of algae in coastal estuaries. These environmental effects, as well as 
the health effects noted above, are described in the Regulatory Impact 
Analysis, and additional information may be found in EPA's ``staff 
papers'' and ``air quality criteria'' documents for ozone and nitrogen 
oxides.10, 11, 12, 13
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    \10\ U.S. EPA, 1996, Review of National Ambient Air Quality 
Standards for Ozone, Assessment of Scientific and Technical 
Information, OAQPS Staff Paper, EPA-452/R-96-007.
    \11\ U.S.EPA, 1996, Air Quality Criteria for Ozone and Related 
Photochemical Oxidants, EPA/600/P-93/004aF.
    \12\ U.S. EPA, 1995, Review of National Ambient Air Quality 
Standards for Nitrogen Dioxide, Assessment of Scientific and 
Technical Information, OAQPS Staff Paper, EPA-452/R-95-005.
    \13\ U.S.EPA, 1993, Air Quality Criteria for Oxides of Nitrogen, 
EPA/600/8-91/049aF.
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2. Current Compliance With the Ozone NAAQS
    Today, many states are finding it difficult to show how they can 
meet or maintain compliance with the current National Ambient Air 
Quality Standard (NAAQS) for ozone by the deadlines established in the 
Clean Air Act (CAA, or ``the Act'').14 As of August, 1998, 
72 million people outside of California lived in 36 metropolitan areas 
and two counties designated nonattainment under the 1-hour ozone NAAQS.
---------------------------------------------------------------------------

    \14\ See 42 U.S.C. 7401 et seq.
---------------------------------------------------------------------------

    In July 1997, EPA established a new 8-hour ozone NAAQS to better 
protect against longer exposure periods at lower concentrations than 
the current 1-hour standard. Under the July 1997 rule, the 1-hour NAAQS 
would still be applicable in certain areas during the transition to the 
8-hour standard (62 FR 38856; July 17, 1997). EPA reviewed ambient 
ozone monitoring data for the period 1993 through 1995 to determine 
which counties violated either the 1-hour or 8-hour NAAQS for ozone 
during this time period.15, 16 Eighty-four counties violated 
the 1-hour NAAQS during this 3-year period, while 248 counties violated 
the 8-hour NAAQS. The 84 counties had a 1990 population of 47 million, 
while the 248 counties had a 1990 population of 83 million. EPA is 
reviewing more recent air quality data for 1996 and 1997. A preliminary 
assessment of 1994 through 1996 ozone monitoring data reveals only 
marginal changes in the number of counties experiencing a nonattainment 
problem with the 8-hour NAAQS, and essentially no change in the 
population levels impacted by nonattainment.
---------------------------------------------------------------------------

    \15\ This use of the term ``nonattainment'' in reference to a 
specific area is not meant as an official designation or future 
determination as to the attainment status of the area.
    \16\ See 63 FR 57356, October 27, 1998, ``Finding of Significant 
Contribution and Rulemaking for Certain States in the Ozone 
Transport Assessment Group Region for Purposes of Reducing Regional 
Transport of Ozone.''
---------------------------------------------------------------------------

    On May 14, 1999, a panel of the U.S. Court of Appeals for the 
District of Columbia Circuit found, by a 2-1 vote, that Clean Air Act 
sections 108 and 109, as interpreted by EPA in establishing the 8-hour 
ozone NAAQS (as well as the new NAAQS for PM2.5 and 
PM10), effect an unconstitutional delegation of 
Congressional power. American Trucking Ass'ns, Inc., et al., v. 
Environmental Protection Agency, Nos. 97-1440, 1441 (D.C. Cir. May 14, 
1999). The Court remanded the record to EPA. One judge dissented, 
finding that the majority's opinion ``ignores the last half-century of 
Supreme Court nondelegation jurisprudence.'' Id., slip op. at 31. The 
Court also ruled, regarding the 8-hour ozone NAAQS, that the statute 
permits EPA to promulgate a revised ozone NAAQS and to designate the 
attainment status of areas. However, the Court curtailed EPA's ability 
to require states to comply with the revised ozone NAAQS. Further the 
Court directed the Agency to determine whether tropospheric ozone has a 
beneficent effect, and if so, assess ozone's net adverse health effect. 
In general, the Court did not find fault with the scientific basis for 
EPA's determinations regarding adverse health effects from ozone. On 
June 28, 1999, EPA filed a petition for rehearing and petition for 
rehearing en banc seeking review of the panel's decision.
    The Court's decision does not address the provisions of section 
202(a), and does not change EPA's belief that the standards in today's 
proposal are lawful and appropriate under these criteria. We believe 
that the information provided in this proposal and the draft Regulatory 
Impact Analysis, as well as the information that EPA relied on in 
setting the NAAQS for ozone, support a conclusion that ozone can be 
reasonably anticipated to endanger the public health or welfare. EPA's 
belief that it is appropriate to seek reductions of NOX and 
NMHCs from heavy duty vehicles and engines to protect public health or 
welfare is not changed by the decision of the court.
3. Future Compliance With the Ozone NAAQS
    Local, state and federal organizations charged with delivering 
cleaner air have mounted significant efforts in recent years to reduce 
air quality problems associated with ground-level ozone, and there are 
signs of partial success. NOX and VOCs appear to have been 
reduced, and average levels of ozone seem to have begun gradually 
decreasing. However, this progress is in jeopardy. EPA projects that 
reductions in ozone precursors that will result from the full 
implementation of current emission control programs will fall far short 
of what would be needed to offset the normal emission increases that 
accompany economic expansion. By the middle of the next decade, the 
Agency expects that the downward trends will have reversed, primarily 
due to increasing numbers of emission sources. By around 2020, EPA 
expects that NOX levels will have returned to current levels 
in the absence of significant new reductions.17 To the 
extent that some areas are seeing a gradual decrease in ozone levels in 
recent years, EPA believes that the expected increase in NOX 
will likely result in an increase in ozone problems in the future.
---------------------------------------------------------------------------

    \17\ See Chapter 2 of the draft Regulatory Impact Analysis for 
this proposal.
---------------------------------------------------------------------------

    The Agency has recently finalized a rulemaking requiring 22 States 
and the District of Columbia to submit State Implementation Plan (SIP) 
revisions to reduce specified amounts of emissions of NOX 
for the purpose of reducing NOX and ozone transport across 
State boundaries in the eastern half of the United States.18 
The specified NOX reduction for each State varies. In making 
this decision EPA relied upon, among other items, ozone modeling 
studies for the eastern U.S. In the baseline scenario for these 
modeling runs EPA included the emission reductions expected from the 
2004 HDDE standards. These modeling runs concluded that significant 
additional NOX reductions beyond the baseline case were 
necessary from 22 eastern States in order to meet the ozone NAAQS 
standards. The NOX emission reductions from the 2004 HDDE 
standards are assumed by these models to be part of the reductions that 
will be needed to meet the ozone NAAQS in these areas. The Agency did 
not analyze the specified reductions that would be required by the rule 
if the baseline did not include the 2004 HDDE standards.
---------------------------------------------------------------------------

    \18\ See 63 FR 57356, October 27, 1998, ``Finding of Significant 
Contribution and Rulemaking for Certain States in the Ozone 
Transport Assessment Group Region for Purposes of Reducing Regional 
Transport of Ozone.''
---------------------------------------------------------------------------

    The deadline for submission of SIPs was recently stayed by a panel 
of the Court of Appeals for the D.C. Circuit pending further review. 
EPA believes that the October 27, 1998 rule is fully consistent with 
the Clean Air Act and

[[Page 58477]]

should be upheld. However, it should be noted that if the emission 
reductions sought by the SIP call are not achieved, it would be more 
difficult to attain the NAAQS for ozone.
    In addition, many states (including western states) have also 
included the emission reductions projected from the 2004 HDDE standards 
in their State Implementation Plans. This demonstrates that these 
states are relying on these emission reductions to meet the ozone 
NAAQS.
4. Contribution of HD Diesel and Gasoline Engines to Total VOC and 
NOX Inventories
    HD engines and vehicles are important contributors to the national 
inventories of NOX emissions, and they contribute moderately 
to national VOC pollution. The draft RIA for this proposal describes in 
detail recent emission inventory modeling completed by EPA for this 
proposal. Table 1 summarizes EPA's current estimates for national 
NOX and VOC contributions from major source categories.

                                  Table 1.--2000 National NOX and VOC Emissions
                                         [thousand short tons per year]
----------------------------------------------------------------------------------------------------------------
                       Emission source                            NOX         NOX %         VOC         VOC %
----------------------------------------------------------------------------------------------------------------
Light-Duty Vehicles.........................................        4,420           19        4,098           25
Heavy-Duty Diesel Vehicles..................................        2,274           10          246            1
Heavy-Duty Gasoline Vehicles................................          318            1          198            1
Nonroad Engines and Vehicles................................        5,343           23        2,485           15
Other (Stationary Point and Area Sources)...................       10,656           47        9,567           58
                                                             ---------------------------------------------------
        Total Nationwide Emissions..........................       22,831  ...........       16,594  ...........
----------------------------------------------------------------------------------------------------------------

    It should be noted that Table 1 does not include estimated 
NOX emission impacts associated with the previously produced 
HD diesel engines at issue in the recent enforcement action involving 
the government and several HD diesel engine manufacturers. The 
relationship of these consent decrees to today's proposed rule is 
described in section III.D. The excess NOX emissions from 
these engines are substantial, and would significantly increase the 
estimated contribution from HD diesel vehicles presented in Table 1. 
However, as discussed in section VI.A of this preamble, we did not 
update our emission inventory model to include the impact on these 
previously produced engines for this proposal.
    Notwithstanding these excess emissions, Table 1 indicates that HD 
gasoline and diesel vehicles will represent approximately 11 percent of 
national NOX emissions and two percent of national VOC 
emissions in the year 2000. The Regulatory Impact Analysis document for 
this proposal contains updated emission inventory modeling for HD 
vehicles. The results show that without additional HD NOX 
control beyond the 1998 standards, national NOX emissions 
from HD vehicles would decline between 2000 and 2005, but this trend 
would stop in 2005. After 2005, NOX emissions from the HD 
vehicle fleet would increase as a result of future growth in the HD 
vehicle market without additional emission controls. A similar trend is 
seen for national NMHC emissions from HD vehicles; however, NMHC 
emissions are projected to decrease until approximately 2010, after 
which changes in the make-up of the fleet result in an increase in the 
NMHC emissions from HD vehicles (see Chapter 5 of the draft RIA).
    We estimate that the HD diesel and gasoline standards contained in 
this proposal will result in a combined reduction by the year 2020 of 
1,629,000 tons of NOX per year and 54,000 tons of 
hydrocarbons (HC) per year. Section VI of this preamble (``What are the 
Environmental Benefits of this Proposal?'') as well as the draft RIA 
for this proposal contain more detailed information on the Agency's 
projected benefits from today's proposal.

B. Need for Additional PM Reductions

1. Health and Welfare Effects From PM
    Particulate matter is the general term for the mixture of solid 
particles and liquid droplets found in the air. Particulate matter 
includes dust, dirt, soot, smoke, and liquid droplets that are directly 
emitted into the air from natural and manmade sources, such as 
windblown dust, motor vehicles, construction sites, factories, and 
fires. Particles are also formed in the atmosphere by condensation or 
the transformation of emitted gases such as sulfur dioxide, nitrogen 
oxides, and volatile organic compounds. Particulate matter, like ozone, 
has been linked to a range of serious respiratory health problems. 
Scientific studies suggest a likely causal role of ambient particulate 
matter in contributing to a series of health effects. The key health 
effects categories associated with particulate matter include premature 
mortality, aggravation of respiratory and cardiovascular disease (as 
indicated by increased hospital admissions and emergency room visits, 
school absences, work loss days, and restricted activity days), changes 
in lung function and increased respiratory symptoms, changes to lung 
tissues and structure, and altered respiratory defense mechanisms. PM 
also causes damage to materials and soiling. It is a major cause of 
substantial visibility impairment in many parts of the U.S.
    Motor vehicle particle emissions and the particles formed by the 
transformation of motor vehicle gaseous emissions (secondary 
particulates) tend to be in the fine particle range. Fine particles 
(those less than 2.5 micrometers in diameter) are a health concern 
because they easily reach the deepest recesses of the lungs. Scientific 
studies have linked fine particles (alone or in combination with other 
air pollutants), with a series of significant health problems, 
including premature death; respiratory related hospital admissions and 
emergency room visits; aggravated asthma; acute respiratory symptoms, 
including aggravated coughing and difficult or painful breathing; 
chronic bronchitis; and decreased lung function that can be experienced 
as shortness of breath.
    These effects are discussed further in the RIA for this proposal, 
as well as the RIA for the 1997 final rule for the 2004 standards, and 
additional information may be found in EPA's ``staff paper'' and ``air 
quality criteria document'' for particulate matter.19
---------------------------------------------------------------------------

    \19\ U.S. EPA, 1996, Air Quality Criteria for Particulate 
Matter, EPA/600/P-95/001aF.
---------------------------------------------------------------------------

2. Current and Future Compliance With the PM10 NAAQS
    The first NAAQS for particulate matter regulated total suspended

[[Page 58478]]

particulate in the atmosphere. In 1987, EPA replaced that standard with 
one for inhalable PM (PM10--particles less than ten microns 
in size), because the smaller particles, due to their ability to reach 
the lower regions of the respiratory tract, are more likely responsible 
for the adverse health effects. The major source of PM10 is 
fugitive emissions from agricultural tilling, construction, fires, and 
unpaved roads. Some revisions to the PM10 standards were 
made in 1997. EPA has also recently added new fine particle standards 
for particles less than 2.5 microns in size (PM2.5). Most of 
the particulate due to motor vehicles falls in the fine particle 
category. These standards have both an annual and a daily component. 
The annual component is set to protect against long-term exposures, 
while the daily component protects against more extreme short-term 
events.
    As noted above, on May 14, 1999, a panel of the U.S. Court of 
Appeals for the District of Columbia Circuit found, by a 2-1 vote, that 
Clean Air Act sections 108 and 109, as interpreted by EPA in 
establishing the new NAAQS for PM2.5 and PM10, 
effect an unconstitutional delegation of Congressional power. American 
Trucking Ass'ns, Inc., et al., v. Environmental Protection Agency, Nos. 
97-1440, 1441 (D.C. Cir. May 14, 1999). The Court remanded the record 
to EPA. The court vacated the new PM10 standard, but has not 
vacated the PM2.5 standard. See American Trucking Ass'ns, 
Inc., et al., v. Environmental Protection Agency, No. 97-1440 (D.C. 
Cir. June 18, 1999).
    Compliance with the current PM10 standard continues to 
be a problem. According to the 1996 EPA Air Quality and Emissions 
Trends report, there were 7 million people living in 15 counties across 
the U.S. which exceeded the PM10 NAAQS in 1996.20
---------------------------------------------------------------------------

    \20\ U.S. EPA, January 1998, ``National Air Quality and 
Emissions Trends Report, 1996'', EPA 454/R-97-0013.
---------------------------------------------------------------------------

    EPA recently projected ambient PM10 levels and the 
number of U.S. counties expected to be in violation of the revised 
PM10 NAAQS in 2010.21 Based on the 1990 census, 
about 10 million people live in the 11 counties projected to be in 
nonattainment of the revised PM10 NAAQS.
---------------------------------------------------------------------------

    \21\ Regulatory Impact Analyses for the Particulate Matter and 
Ozone National Ambient Air Quality Standards and Proposed Regional 
Haze Rule, Innovative Strategies and Economics Group, Office of Air 
Quality Planning and Standards, U.S. Environmental Protection 
Agency, Research Triangle Park, N.C., July 16, 1997.
---------------------------------------------------------------------------

3. Contribution of HD Diesel and Gasoline Vehicles to PM Inventories
a. Contribution to National PM10 Inventories
    The national inventory of PM10 is dominated by natural 
sources (wind erosion) and so-called miscellaneous sources, which 
include paved and unpaved road dust, agricultural crops, fugitive dust, 
and dust from construction activities. Together natural and 
miscellaneous sources represented approximately 90 percent of national 
PM10 emissions in 1996. Since these sources are not readily 
amenable to regulatory standards and controls, it is appropriate to 
focus on more traditional ``controllable'' portions of the particulate 
pollution problem when considering the need for PM controls. Excluding 
natural and miscellaneous sources, HD vehicles (gasoline and diesel) 
represent approximately five percent of the remaining man-made sources 
of PM10 in 1996, virtually all (95 percent) of which is from 
diesel vehicles.22
---------------------------------------------------------------------------

    \22\ U.S. EPA, December 1997, ``National Air Pollutant Emission 
Trends, 1900-1996'', EPA-454/R-97-011.
---------------------------------------------------------------------------

    In the proposal for the 1997 final rule for the 2004 standards, EPA 
presented data on future projections of mobile and stationary source 
PM10 national emission inventories out to the year 2010, as 
well as a break-down of mobile sources into on-highway light-duty, on-
highway heavy-duty, and nonroad categories (see 61 FR 33432-33440, June 
27, 1996). These projections showed that without additional future 
controls on PM or NOX emissions, annual PM emissions (tons/
year) for all mobile sources would begin to rise after the year 2000. 
The Regulatory Impact Analysis document for this proposal presents the 
results of updated emission modeling specifically for HD vehicles. 
These results show that the annual national PM10 emissions 
from HD vehicles (tons/year) are expected to decline between now and 
approximately the year 2010, after which increases in the size of the 
fleet will result in a steady increase into the future (see Chapter 5 
of the draft RIA).
b. Source-apportionment Studies for Diesel PM
    Discussion of PM inventories from HD vehicles, and in particular HD 
diesel vehicles which represent the vast majority of the HD PM 
emissions, can be discussed in terms other than just contributions to 
national yearly emission inventories. In recent years several research 
groups have been looking at the contribution of diesel PM in selected 
urban and rural areas. In several cases these studies indicate that the 
contribution from diesels in certain urban areas to PM emissions is 
much larger than is indicated by national PM inventories. Several 
studies have been performed in the past several years which have 
attempted to apportion particulate matter collected at specific sites 
to individual source categories, i.e., source apportionment studies. 
These studies collect particulate matter samples in the ambient air 
which are subsequently analyzed using various chemical techniques in 
order to estimate what sources contributed to the sample.
    There have been a number of source apportionment studies for mobile 
source particulate emissions. Among the most recent and thorough are 
studies by the state of Colorado (the Northern Front Range Air Quality 
Study [NFRAQS]) for the Denver area and the California Institute of 
Technology for the Los Angeles area. These studies emphasize 
particulate smaller than 2.5 microns. Also, EPA has a cooperative 
agreement with the Desert Research Institute (DRI); under this 
agreement, DRI is completing a detailed report on mobile source 
particulates; a major portion of this report summarizes source 
apportionment studies for particulates that include those from mobile 
sources.23
---------------------------------------------------------------------------

    \23\ Draft report for EPA from the Desert Research Institute, 
June 30, 1998, Available in EPA Air Docket A-98-32, Item # 
--01.
---------------------------------------------------------------------------

    Source apportionment work involves collecting and analyzing a 
number of ambient particulate samples from a number of specific sources 
such as gasoline and diesel vehicles. Some samples of high molecular 
weight hydrocarbons are frequently also collected and analyzed, these 
hydrocarbons can be transformed to particulates in the ambient air; 
such compounds include polycyclic organic matter. These samples are 
analyzed in detail to determine what specific compounds are present 
including those in trace amounts that are more common from one source 
type than from others, these traces are called source signatures. From 
these analyses, a number of source signatures are developed including 
those for gasoline and diesel vehicles. Source apportionment work also 
involves collecting and analyzing a larger number of ambient 
particulate and, frequently, high molecular weight hydrocarbon. The 
compounds found in these samples can be compared to the source 
signatures to determine what and how much individual sources contribute 
to the ambient particulate.

[[Page 58479]]

Source apportionment work is subject to complications and uncertainty. 
Thus, no single study should be considered definitive. Additional 
information on source apportionment techniques, and the uncertainties 
associated with the techniques, can be found in Chapter 2 of the RIA 
for this proposal.
    The NFRAQS study analyzed ambient particulate samples in the 
Colorado area including Denver using data it collected on the chemical 
speciation from specific source types to determine how much various 
mobile and stationary source types contribute to PM2.5. 
Authorized by Colorado state legislation, the total study was funded by 
37 government, industry, and trade association groups. The many outputs 
and conclusions from the NFRAQS will not be discussed here, only source 
apportionment results for diesel engines are summarized. Complete 
copies of the NFRAQS are available from the following World Wide Web 
site, http://charon.cira.colostate.edu/. The NFRAQS included several 
time periods and several locations in and around Denver. Two locations, 
Brighton and Welby, during the winter of 1997 included the most 
detailed sampling and analysis, which allowed the researchers to 
estimate very detailed source specific contributions, including the 
contributions to PM2.5 from diesel exhaust (all diesel, 
nonroad and on-highway sources were not differentiated). Based on this 
work, it was estimated that diesel exhaust sources contributed 10 
percent of the total mass of PM2.5 in the areas of Brighton 
and Welby in the winter of 1997.
    Similar work has been done for the Los Angeles area by a group of 
researchers at the California Institute of Technology. This work 
concluded that direct emissions from diesel exhaust represented 
approximately 30 percent of fine PM mass on an annual basis in downtown 
Los Angeles in 1982.24 In follow-on work looking at the city 
of Claremont, California in 1987, direct diesel exhaust was found to 
represent approximately 13 percent of PM2.5 mass, and 9 
percent of PM10 mass.25
---------------------------------------------------------------------------

    \24\ ``Source Apportionment of Airborne Particulate Matter Using 
Organic Compounds as Tracers'', J.J. Schauer, W.F. Rogge, L.M. 
Hildemann, M.A. Mazurek, and G.R. Cass, Atmospheric Environment, 
Vol. 30, No. 22, 1996.
    \25\ ``Source Contributions to the Size and Composition 
Distribution of Urban Particulate Air Pollution'', M.J. Kleeman and 
G.R. Cass, Atmospheric Environment, Vol. 32, No. 16, 1998.
---------------------------------------------------------------------------

    The California Institute of Technology has also collected ambient 
particulate in the Boston, MA and Rochester, NY areas. These samples, 
especially those for Boston, show that carbonaceous particulate is the 
largest single constituent in PM2.5 for these areas. Mobile 
source particulate, including diesels, is an important contributor to 
carbonaceous particulate. The Boston and Rochester samples have not yet 
been used for source apportionment work.
    Other ambient samples collected in the eastern U.S. such as 
Washington, DC show carbonaceous particulate to be an important 
constituent of PM2.5, although sulfates is a somewhat larger 
constituent and nitrates a much smaller constituent. Particulate 
samples collected in the western U.S. such as in Spokane, WA, Phoenix, 
AZ and the San Joaquin Valley of California show that carbonaceous 
particulate is the major constituent with sulfates/nitrates being 
lesser constituents although nitrates are more important in southern 
California than elsewhere in the United States. This work is summarized 
in the EPA report ``National Air Pollutant Emission Trends, 1900-
1996.'' 26
---------------------------------------------------------------------------

    \26\ ``National Air Pollutant Emission Trends, 1900-1996'', EPA 
Report 454/R-97-011, December 1997.
---------------------------------------------------------------------------

    The reports on source apportionment summarized in this section 
indicate that the contribution of diesel engines to PM inventories in 
several local areas around the U.S. are much higher than what would be 
assumed from looking only at the estimates presented in national PM 
emission inventories. One possible explanation for this is the 
concentrated use of diesel engines in certain local or regional areas 
which is not well represented by the national, yearly average presented 
in national PM emission inventories.

C. Air Toxics From HD Engines and Vehicles

    In addition to contributing to the health and welfare problems 
associated with exceedances of the National Ambient Air Quality 
Standards for ozone and PM10, emissions from HD diesel and 
Otto-cycle vehicles include a number of air pollutants that increase 
the risk of cancer or have other negative health effects. These air 
pollutants include benzene, formaldehyde, acetaldehyde, 1,3-butadiene, 
and diesel particulate matter. For several of these pollutants, motor 
vehicle emissions are believed to account for a significant proportion 
of total nation-wide emissions. All of these compounds are products of 
combustion; benzene is also found in nonexhaust emissions from 
gasoline-fueled vehicles. These reductions in hydrocarbon emissions 
from HD vehicles resulting from today's proposal will further reduce 
the potential cancer risk and other health risks from these air toxics 
(other than diesel PM) because many of these pollutants are themselves 
VOCs. Diesel engine particulate matter is also a potential concern 
because of its possible carcinogenic and mutagenic effects on people. 
Diesel PM is made of hundreds of chemical species, including many 
organic and metallic compounds. Researchers have been investigating the 
potential health hazards associated with exposure to diesel PM for many 
years.27 EPA's Office of Research and Development is 
currently updating the EPA's diesel emission health assessment 
document. However, the document has only been released as a preliminary 
draft, and is currently undergoing review by the Clean Air Scientific 
Advisory Committee. A final version is not expected to be available 
until late 1999.28
---------------------------------------------------------------------------

    \27\ ``Diesel Exhaust: A Critical Analysis of Emissions, 
Exposure, and Health Effects'', Health Effects Institute, April, 
1995.
    \28\ ``Preliminary Draft--Health Assessment Document for Diesel 
Emissions'', U.S. EPA, February 1998, EPA 600/8-90/057C.
---------------------------------------------------------------------------

    The California Air Resources Board and the California Office of 
Environmental Health Hazard Assessment (COEHHA) have undertaken an 
assessment of the cancer and non-cancer effects from exposure to diesel 
exhaust, including the particulate matter component of diesel exhaust, 
to determine whether diesel exhaust should be classified as a Toxic Air 
Contaminant (TAC) under California law. The evaluation of diesel 
exhaust by CARB and COEHHA began in 1989, in June of 1998 a Staff 
Report was published which recommended that diesel exhaust be 
classified as a TAC.29 In a CARB Board hearing held in 
August, the Board decided to identify diesel exhaust particulate matter 
as a TAC.30
---------------------------------------------------------------------------

    \29\ California Air Resources Board--Staff Report--``Proposed 
Identification of Diesel Exhaust as a Toxic Air Contaminant'', June 
1998.
    \30\ California Air Resources Board, Resolution 98-35, August 
27, 1998.
---------------------------------------------------------------------------

    EPA will be addressing the issues raised by air toxics from motor 
vehicles and their fuels in a separate rulemaking that EPA is 
initiating in the near future under section 202(l)(2) of the Act. That 
rulemaking will address the emissions of hazardous air pollutants from 
motor vehicles and fuels, and the appropriate level of control of 
hazardous air pollutants from these sources.

III. What Is the Important Background Information for This 
Proposal?

    Under EPA's classification system, heavy-duty vehicles are those 
with a

[[Page 58480]]

GVWR of 8,500 pounds or more.\31\ The State of California classifies 
the lighter end of this class--up to 14,000 pounds GVWR--as ``medium-
duty vehicles.'' Heavy-duty engines are engines used in heavy-duty 
vehicles. Heavy-duty engines and vehicles are used in a wide range of 
applications, from large full size pick-up trucks to the largest 
commercial trucks. Because one type of heavy-duty engine may be used in 
many different applications, EPA emission standards for the heavy-duty 
class of vehicles have historically been based on the emissions 
performance of the engine (and any associated aftertreatment devices) 
as tested separately from the vehicle chassis.
---------------------------------------------------------------------------

    \31\ The Clean Air Act defines heavy-duty vehicles as those with 
a GVWR of 6,000 pounds. However, EPA has classified vehicles between 
6,000 and 8,500 pounds GVWR as light-duty vehicles, while treating 
them as heavy-duty for statutory purposes. Vehicles weighing between 
6,000 and 8,500 pounds GVWR are not addressed generally in this 
proposed rulemaking.
---------------------------------------------------------------------------

    Highway HDEs are categorized into diesel-cycle (compression-
ignited) and Otto-cycle (spark-ignited) engines. Most diesel-cycle 
engines are fueled by diesel fuel, but heavy-duty diesel-cycle engines 
can also be fueled by methanol or natural gas. The heavy-duty diesel 
engine class is further subdivided by EPA into three subclassifications 
or ``primary intended service classes''; light, medium, and heavy HDDEs 
(see 40 CFR 86.090-2). HDDEs are categorized into one of the three 
subclasses depending on the GVWR of the vehicles for which they are 
intended, the usage of the vehicles, the engine horsepower rating, and 
other factors. The subclassifications allow EPA to more effectively set 
requirements that are appropriate for the wide range of sizes and uses 
of HDDEs.
    Most highway heavy-duty Otto-cycle vehicles and engines are 
gasoline-fueled, but may also be fueled with alternative fuels 
including methanol and gaseous fuels such as natural gas. Heavy-duty 
Otto-cycle vehicles and engines include large full size pick-up trucks, 
full size cargo and passenger vans, and the largest sport utility 
vehicles. Approximately 75 percent of heavy-duty Otto-cycle vehicles 
are in the 8,500-10,000 pound GVWR range, and the vast majority of 
these are sold as ``complete'' vehicles. The majority of heavy-duty 
Otto-cycle vehicles above 10,000 pounds GVWR are sold as ``incomplete'' 
vehicles, meaning that they are manufactured without their primary 
cargo carrying container or device attached. These incomplete vehicles 
(basically the engine plus a chassis) are then manufactured into a 
variety of vehicles, including recreational vehicles, panel trucks, tow 
trucks, and dump trucks.
    EPA's NOX standard for 1998 and later model year diesel 
and Otto-cycle heavy-duty engines is 4.0 grams per brake horsepower-
hour (g/bhp-hr). The hydrocarbon standards for 1998 and later model 
year Otto-cycle engines are 1.1 g/bhp-hr for engines used in lighter 
vehicles (8500 to 14,000 pounds GVWR) and 1.9 g/bhp-hr for engines used 
in heavier vehicles (greater than 14,000 pounds GVWR), and the 1998 and 
later model year hydrocarbon standard for HDDEs is 1.3 g/bhp-hr. EPA 
currently requires testing of the engine (with emissions control 
systems in place) rather than the entire vehicle. Thus, the standards 
are in units of g/bhp-hr (i.e., grams of emissions per unit of work the 
engine performs over the test cycle), rather than the grams-per-mile 
unit currently used for testing passenger cars and light-duty trucks.
    This proposed rulemaking is the continuation of a rulemaking 
process for heavy-duty engines which began in 1995 with an Advanced 
Notice of Proposed Rulemaking (ANPRM) (60 FR 45580, August 31, 1995). 
As discussed below, a 1996 Notice of Proposed Rulemaking proposed the 
same NMHC+NOX standards for both Otto-cycle and diesel 
engines (61 FR 33421, June 27, 1996). However, EPA did not finalize the 
proposed NMHC+NOX standard for Otto-cycle engines in the 
final rule published in October 1997 (62 FR 54694, October 21, 1997). 
EPA did finalize a new NMHC+NOX emission standard for HDDEs, 
starting with the 2004 model year, but committed to review the 
appropriateness of this standard in 1999. This NPRM thus addresses two 
broad issues that remain from earlier rulemaking efforts--a review of 
the NMHC+NOX standard for diesel engines and a supplemental 
proposal addressing new NMHC+NOX standards for heavy-duty 
Otto-cycle engines and vehicles. The previous rulemaking documents, and 
the documents referenced therein (see EPA Air Docket No. A-95-27), 
contain extensive background on the engines and vehicles, the affected 
industry, and the need for lower emissions standards.

A. Statement of Principles and Rulemaking History

    In July of 1995, EPA, the California Air Resources Board, and 
heavy-duty engine manufacturers representing over 90 percent of annual 
nationwide engine sales signed a Statement of Principles (SOP) that 
established a framework for a proposed rulemaking to address concerns 
regarding the growing contribution of heavy-duty engines to air 
pollution problems. The SOP contained levels for a new proposed 
standard for NMHC+NOX that would become effective in model 
year 2004. The SOP also contained several key provisions in addition to 
the standards. The SOP discusses the need to review in 1999 the 
technological feasibility of the NMHC+NOX standard and its 
appropriateness under the Clean Air Act. Also, the SOP outlines a plan 
for developing technology with the goal of reducing NOX 
emissions to 1.0 g/bhp-hr and particulate matter to 0.05 g/bhp-hr while 
maintaining performance, reliability, and efficiency of the engines. 
EPA sought early comment on the general regulatory framework laid out 
in the SOP in an ANPRM on August 31, 1995 (60 FR 45580), then 
subsequently issued an NPRM on June 27, 1996 (61 FR 33421).
    On October 21, 1997, EPA issued a final rule (62 FR 54694). The 
centerpiece of the final rule was the new NOX + NMHC 
standard of 2.4 g/bhp-hr (or 2.5 g/bhp-hr with a 0.5 g/bhp-hr NMHC cap) 
for 2004 and later model year heavy-duty diesel-cycle engines. The rule 
also adopted other related compliance provisions for diesel-cycle 
heavy-duty engines beginning with the 2004 model year, as well as 
revisions to the useful life for the heavy heavy-duty diesel engine 
service class. As explained in the following section, no new standards 
were finalized for on-highway heavy-duty Otto-cycle engines.
    The final rule also contained modified ABT provisions for heavy-
duty diesel engines, allowing EPA to finalize a more stringent engine 
standard than might otherwise be appropriate under the CAA, since ABT 
reduces the cost and improves the technological feasibility of 
achieving the NMHC+NOX standard. The changes to the ABT 
program provide the manufacturers with additional product planning 
flexibility and the opportunity for a more cost-effective introduction 
of product lines meeting the new standard. We also believe that the ABT 
program can create an incentive for the early introduction of new 
emission control technology. EPA did not finalize new ABT provisions 
for Otto-cycle engines because EPA did not take action at that time on 
new standards for those engines. In summary, engine manufacturers will 
be able to generate credits under the new program beginning with the 
1998 model year for use only in 2004 and later model years. The credits 
in the modified program will have unlimited life, as opposed to the 
three year credit life contained in the current HD program. Also, 
engines

[[Page 58481]]

with certification levels at or below a certain cut point are able to 
generate undiscounted credits. Credits generated by engine families 
certified above the specified cut point are discounted by 10 percent 
for purposes of banking and trading. The pre-existing ABT program was 
retained for engine families using credits before 2004, and for Otto-
cycle engines which cannot earn credits in the modified program, as 
noted above. In 2004, the certification level cut-point is adjusted to 
reflect the implementation of the new standard.
    EPA also finalized several provisions to help ensure in-use 
durability. First, EPA increased the useful life period for heavy 
heavy-duty diesel engines to 435,000 miles. This new useful life 
represents a 50 percent increase and is more representative of the 
durability of current and future heavy heavy-duty diesel engines. In 
addition, longer allowable maintenance intervals were finalized for 
some critical emission-control components, including exhaust gas 
recirculation (EGR) systems, catalysts, and other add-on emissions 
control components. Generally, the maintenance intervals for the 
components are set at 100,000 miles for light heavy-duty diesel engines 
and 150,000 miles for medium and heavy heavy-duty diesel engines. 
Warranty regulations were also revised to better reflect current 
industry practices.
    Other provisions of the October, 1997 final rule address the period 
after the manufacturer's responsibility for emission control ends, 
including engine rebuilding. One of those provisions requires engine 
manufacturers to establish a section in the owner's manual for add-on 
components that includes recommendations for maintenance and diagnosing 
malfunction. In addition, all on-board monitoring used to satisfy the 
engine's allowable maintenance must not be designed to turn off after 
the end of the useful life. Finally, EPA established provisions to 
address engine rebuilding which specify what actions are needed to 
ensure proper operation of emissions control components and ensure that 
rebuilding does not result in loss of emissions control. Removal or 
disabling of emissions related components, resulting in a higher 
emitting vehicle, are considered tampering.

B. 1999 Review of Heavy-Duty Diesel Engine NMHC+NOX 
Standards

    In addition to the elements of the final rule described above, EPA 
finalized a regulatory provision providing for a 1999 review of the new 
NMHC+NOX emission standard for HDDEs. EPA committed to 
``reassess the appropriateness of the standards under the Clean Air 
Act, including the need for and technical and economic feasibility of 
the standards based on information available in 1999'' (See 62 FR 
54699, October 21, 1997). This provision was put in place because the 
technologies required to meet the 2004 NMHC+NOX standard for 
HDDEs were, at the time the standard was finalized, not yet fully 
developed and proven. This commitment was spelled out in regulatory 
language in the final rule in 40 CFR 86.004-11, paragraph (a)(1)(i)(E), 
which reads:

    No later than December 31, 1999, the Administrator shall review 
the emissions standards set forth in paragraph (a)(1)(i) of this 
section and determine whether these standards continue to be 
appropriate under the Act.

    In the preamble to the 1997 final rule EPA outlined the three 
potential outcomes of the 1999 review: further tightening of the 
NMHC+NOX standard, no change to the standard, or a 
relaxation of the standard. The preamble noted that if EPA determined 
through the 1999 review process that a tighter standard was feasible 
and appropriate under the Clean Air Act, such tighter standard would be 
proposed. Conversely, if EPA's 1999 review process concluded that the 
2004 NMHC+NOX standard was not technologically feasible, the 
1997 preamble outlined alternative less stringent sets of standards 
that EPA would propose. These alternative less stringent standards 
would depend on EPA's conclusions regarding the necessity for diesel 
fuel changes and, if changes were found to be needed, whether or not 
EPA took action to require such changes. Specifically, the preamble 
stated that if EPA finds through the 1999 review process that the 
existing 2004 NMHC+NOX standard is not feasible, a standard 
no higher than 2.9 g/bhp-hr NMHC+NOX (or 3.0 g/bhp-hr 
NMHC+NOX with a limit of 0.6 g/bhp-hr NMHC) would be 
proposed. If EPA were to find that changes to diesel fuel would be 
necessary to meet the 2004 NMHC+NOX standards, and if EPA 
did not engage in a rulemaking to make such changes, then standards no 
higher than 3.4 g/bhp-hr NMHC+NOX (or 3.5 g/bhp-hr 
NMHC+NOX with a limit of 0.6 g/bhp-hr NMHC) would be 
proposed.
    While the specific regulatory provision is limited to the 
NMHC+NOX standard for review in 1999, in the preamble to the 
final rule EPA committed to investigating or seeking comment on several 
other issues in the context of the 1999 review. These additional issues 
include:
     An evaluation of whether the appropriateness and technical 
feasibility of the 2004 standards depend upon changes to diesel fuel.
     A reassessment of the appropriateness of the 2004 
NMHC+NOX standard in the context of the current PM standard.
     Non-conformance penalty provisions for the 2004 HDDE 
standards.

C. Proposal for Heavy-Duty Gasoline Engine Standards

1. Summary of Comments on 1996 NPRM
    As was noted above, EPA proposed the same NMHC+NOX 
standard for diesel and Otto-cycle heavy-duty engines in the 1996 NPRM. 
In the comment period following the NPRM, several commenters urged the 
Agency to reconsider its proposal for Otto-cycle engines. The 
commenters argued that the proposal ignored the true low emissions 
capability of gasoline-powered vehicles equipped with advanced three 
way catalysts. Environmental groups provided comments highlighting 
manufacturers' certification data for the 1996 model year, which 
included some engine families with emission levels considerably below 
the standards proposed for the 2004 model year. One commenter 
recommended that the proposed standard be phased in earlier than 2004 
for Otto-cycle engines since the emissions control technology capable 
of meeting the NMHC+NOX standard was more advanced for Otto-
cycle engines than for diesel engines.
    Manufacturers commented that the proposed standard was appropriate 
for Otto-cycle engines and that EPA should not use certification data 
as a basis for determining the feasibility of a lower standard. 
Manufacturers noted that due to the potential for in-use deterioration 
of catalysts and oxygen sensors, they must design to emissions targets 
and certification levels well below the standards. Catalysts experience 
wide variations in exhaust temperature due to the wide and varied usage 
of vehicles in the field. Some vehicles may experience more severe in-
use operation than is represented by the durability testing conducted 
for engine certification. Manufacturers argued that this variation in 
in-use operation has an impact on emission system durability not 
represented by engine certification data and deterioration factors. 
They argued that it is necessary to certify engines to levels well 
below the standards to ensure in-use compliance of all engines. One 
manufacturer presented light-duty

[[Page 58482]]

vehicle and light-duty truck data to demonstrate that certification 
levels were about half the standard while some vehicles' in-use 
emissions levels were higher although not above the standard.\32\
---------------------------------------------------------------------------

    \32\ Comments from Kelly Brown, Ford Motor Company, to Margo 
Oge, Director OMS, U.S. EPA, September 9, 1996, Docket A-95-27, IV-
D-26.
---------------------------------------------------------------------------

2. Analysis Leading to Decision To Not Finalize Otto-Cycle Standards
    EPA, in deciding whether to finalize the NMHC+NOX 
standard as originally proposed, had to determine if the proposed 
standards met the requirements of section 202(a)(3)(A) of the Clean Air 
Act.\33\ For Otto-cycle engines, EPA examined 1997 model year 
certification data and found some engines certified to very low 
emissions levels. The certification data for 1997 showed a large number 
of engine families emitting at or below the 2004 levels as they were 
proposed, with some engines certified at emission levels only ten to 
twenty percent of the proposed 2004 emission standards. Examples of 
these engines are listed in Table 2.\34\
---------------------------------------------------------------------------

    \33\ Section 202(a)(3)(A) of the Clean Air Act specifies that 
regulations ``shall contain standards which reflect the greatest 
degree of emission reduction achievable through the application of 
technology which the Administrator determines will be available for 
the model year to which such standards apply, giving appropriate 
consideration to cost, energy, and safety factors associated with 
the application of such technology.''
    \34\ Note that the text here is a brief assessment of the 
information EPA had available at the time a decision was made to 
refrain from finalizing heavy-duty Otto-cycle standards. However, 
today's proposal, and the accompanying analysis of feasibility in 
the RIA, uses more recent data.

                        Table 2.--1997 MY Heavy-Duty Otto-Cycle Engine Certification Data
----------------------------------------------------------------------------------------------------------------
                                                                   NOX        HC certification
                    Engine size (liter)                       certification     level (g/bhp-   NOX + HC  (g/bhp-
                                                            level (g/bhp-hr)         hr)               hr)
----------------------------------------------------------------------------------------------------------------
4.3.......................................................               1.2               0.3               1.5
5.4.......................................................               0.2               0.1               0.4
5.7.......................................................               1.4               0.1               1.5
6.8.......................................................               0.1               0.1               0.2
7.4.......................................................               1.2               0.4               1.6
8.0.......................................................               2.2               0.1               2.3
Emission Standards........................................               5.0              *1.3               N/A
----------------------------------------------------------------------------------------------------------------
*(1.9 above 14,000 pounds GVWR)

    EPA also examined certification data for California vehicles. 
California's MDV program requires all complete heavy-duty vehicles 
(i.e., all vehicles that exit the manufacturer's assembly line with 
their cargo carrying device or container attached) up to 14,000 pounds 
GVWR to be certified on the chassis-based (vehicle) federal test 
procedure (EPA currently requires engine-based testing of vehicles in 
this class). Table 3 lists examples of model year 1997 California 
vehicle certification results for vehicles above 8,500 pounds GVWR.\35\ 
These vehicles were required to meet the California Tier 1 standards 
which are listed on the table. Starting with the 1998 MY, California is 
requiring manufacturers to begin phase-in of vehicles meeting more 
stringent Low Emission Vehicle (LEV) standards which are also listed in 
Table 3 for these vehicles.
---------------------------------------------------------------------------

    \35\ All of the vehicles and standards listed are categorized 
MDV3 in the medium duty vehicle program which includes vehicles with 
test weights between 5,751-8,500. Test weight is the average of the 
curb weight and gross vehicle weight.

                       Table 3.--1997 MY California Medium-Duty Vehicle Certification Data
                                                 [120,000 mile]
----------------------------------------------------------------------------------------------------------------
                                                                  NOX level  (g/   HC level  (g/    NOX+HC (g/
                       Engine size (liter)                             mile)           mile)           mile)
----------------------------------------------------------------------------------------------------------------
5.4.............................................................            0.20           0.220            0.42
5.7.............................................................            0.88           0.160            1.04
6.8.............................................................            0.42           0.300            0.72
7.4.............................................................            0.48           0.210            0.69
7.5.............................................................            0.24           0.190            0.43
8.0.............................................................            0.51           0.234            0.74
Tier 1 standards................................................            1.53           0.560             N/A
LEV standards...................................................            0.90           0.280             N/A
----------------------------------------------------------------------------------------------------------------

    EPA understands that manufacturers have established certification 
levels which represent typical vehicle usage and that manufacturers 
have given themselves a significant margin between the certification 
levels and the standards to account for variability including more 
severe usage and deterioration. However, EPA found that some 1997 model 
year engines were certified to very low levels even taking the need for 
a compliance margin into consideration. At the time, however, EPA did 
not believe it was appropriate, given the lack of a full opportunity 
for notice and comment, and the need for more thorough data and 
analyses, to proceed directly to finalizing standards tighter than 
those originally proposed for heavy-duty Otto-cycle engines. For these 
reasons, EPA did not finalize the proposed standards for Otto-cycle 
engines and asserted that more stringent standards might be reasonably 
achievable in the 2004 model year time frame. With the lead time 
available for the 2004 time frame and in the context of EPA's emission 
control program at the time, EPA concluded in 1997 that final action 
establishing an appropriate standard for Otto-cycle heavy-duty engines 
should be the subject of a future action that more thoroughly assessed

[[Page 58483]]

whether a more stringent standard might be achievable and appropriate 
for some or all categories of Otto-cycle heavy-duty engines.

D. Consent Decrees With Heavy-Duty Diesel Engine Manufacturers

    The Department of Justice and EPA recently filed proposed consent 
decrees with seven of the largest heavy-duty diesel engine 
manufacturers in the U.S. in order to resolve the problems uncovered 
from current and past heavy-duty diesel engines which the government 
does not believe meet existing standards and defeat device rules. (See 
63 FR 59330-59334; November 3, 1998). In these consent decrees with the 
Federal Government these manufacturers have agreed, among other things, 
to meet a 2.5g/bhp-hr limit on NMHC+NOX no later than 
October 1, 2002. The majority of these engine manufacturers have also 
agreed to produce engines by October 1, 2002 which meet a 1.25 not-to-
exceed limit, a 1.0 Euro III limit (on which the Agency's proposed 
supplemental steady-state cycle is based), and to test engines over and 
eventually comply with a load response test and limit. \36\ The fact 
that these engine manufacturers have agreed to meet the 2004 standards 
in 2002 gives the Agency additional confidence that the 
NMHC+NOX standard being reaffirmed in today's proposal is 
appropriate for the 2004 model year. Other elements of these consent 
decrees that are carried over to today's proposed rule include the 
addition of a new steady state certification test and a new ``not-to-
exceed'' (NTE) approach to in-use testing. In addition, under the 
consent decrees the manufacturers are required to invest considerable 
resources to evaluate instrumentation and methodologies for on-road 
testing, providing an additional basis for EPA's expectations regarding 
the advancement of technology in this area.
---------------------------------------------------------------------------

    \36\ The Consent Decrees establish target limits for a load 
response test of 1.3 times the federal test procedure (FTP) standard 
for NMHC+NOX and 1.7 times the FTP standard for PM. These 
limits would take effect for affected manufacturers after October 1, 
2002. However, the Consent Decrees establish a process to determine 
whether these limits should be modified to ensure that they are the 
lowest achievable given the technology available at the time. Under 
this process, manufacturers would submit load response test data 
with their certification applications starting with the 1999 model 
year, and by October 1, 2000, the parties to the Consent Decrees 
would review these data to determine appropriate emission limits.
---------------------------------------------------------------------------

    The Agency believes these consent decrees will partially address 
the emission problems from these previously produced engines. However, 
we do not believe that relying on the current compliance program and 
the use of enforcement actions in the future is the most appropriate 
method to assure in-use compliance of heavy-duty engines under all 
operating conditions. We estimate that the more than 1,000,000 engines 
at issue in these consent decrees produced since 1988 will have 
resulted in excess NOX emissions of more than 15 million 
tons over the lifetime of the engines, with an estimated 1.3 million 
excess tons of NOX being emitted in 1998 alone. This level 
of NOX emissions is enormous. To put this in perspective, 
the Agency's National Air Pollutant Emission Trends report for 1900-
1996 estimates the total U.S. emission inventory for annual 
NOX emissions was 23.3 million tons. These estimates do not 
include the previously unknown excess NOX emissions from on-
highway heavy-duty diesels. Assuming the total 1998 national 
NOX emissions are similar to 1996, the 1.3 million tons 
excess NOX emissions from heavy-duty diesels in 1998 
represent approximately five percent of the national total. We believe 
the new compliance requirements proposed in this NPRM must be put in 
place in order to assure that the public's health and welfare are 
protected from these types of excess emissions in the future.

IV. What Are the Details of This Proposal?

A. Reaffirmation of 2004 NMHC + NOX Standard for Heavy-Duty 
Diesel Engines

    In today's proposal, the Agency is reaffirming the technological 
feasibility, cost-effectiveness, and appropriateness under the Clean 
Air Act of the 2004 NMHC+NOX standard for HDDEs, including 
the appropriateness of the current 0.1g/bhp-hr PM standard. In 1997, 
the Agency finalized on-highway heavy-duty diesel standards for model 
year 2004 of:

2.4 g/bhp-hr NMHC + NOX

    or

2.5 g/bhp NMHC + NOX with a limit of 0.5 g/bhp-hr on NMHC

    For today's proposal, the Agency has conducted a thorough analysis 
of information and data which has become available since the 
finalization of these standards in October of 1997. As discussed 
elsewhere in this preamble and in the RIA for this proposal, 
manufacturers have made significant progress toward meeting the 2004 
standards, and in fact, the Agency believes a large number of 
manufacturers will be meeting the 2004 model year standards by the end 
of 2002. Manufacturers have made significant progress in several key 
technologies for HD diesels which will allow them to meet the 2004 
NMHC+NOX standards. These areas included advanced fuel 
injection systems, EGR, advanced turbocharger systems, and advanced 
electronic controls. In the relatively short time frame since the 
finalization of the 1997 rule, manufacturers have either announced or 
begun to introduce second generation electronically controlled fuel 
injection systems, such as the Cummins Accumulator Pump system (CAPS), 
and the Navistar/Caterpillar second generation hydraulicly actuated 
electronic unit injections (HEUI) and mechanically actuated electronic 
unit injection (MEUI) systems.\37\ \38\ \39\ \40\ \41\ These newer 
systems provide manufacturers with enormous capabilities to tailor-fit 
engine injection pressures, injection rate shaping, and pilot injection 
(or multiple pilot injections) to lower NOX emissions while 
still complying with the current PM standard, and maintaining or 
improving upon the fuel efficiency, performance, and durability 
expected by HDDE users. These advanced fuel systems will be coupled 
with new, sophisticated EGR systems. As discussed in the RIA, 
considerable research has been done in the last few years on the 
application of EGR to heavy-duty diesels in order to meet the 2004 
standards. Based on this relatively recent information, it now appears 
manufacturers will use a combination of hot and cooled EGR, sometimes 
at relatively high EGR flow rates, on the order of 40-50 percent under 
certain operating conditions, to achieve the 2004 NMHC+NOX 
standards. The Agency believes EGR is perhaps the single most 
significant advance in emission control technology for HD diesels which 
will enable the approximately 50 percent reduction in NOX 
emissions required by the 2004 standards. As discussed in the draft 
RIA, cooled EGR is very effective at reducing NOX emissions. 
Laboratory studies have shown that EGR can reduce NOX 
emissions by up to 90 percent at

[[Page 58484]]

light load and up to 60 percent at full load near rated 
speed.42 Other studies have shown similar reductions at 
other speeds and loads.43 In addition to fuel system changes 
and EGR, turbocharger manufacturers and engine manufacturers are in the 
process of developing new variable nozzle turbochargers (VNT, sometimes 
referred to as variable geometry turbochargers), as well as more 
advanced, electronically controlled wastegated turbochargers, for both 
performance and emission reasons. The new VNT systems will allow 
manufacturers more flexibility in how they design their EGR systems, 
and provide improved performance for engine users. Finally, engine 
manufacturers continue to develop and introduce highly sophisticated 
electronic control management systems based on the latest 
microprocessor technology available.\44\ These next generation control 
systems integrate the complete engine/powertrain system, including the 
injection system, EGR, and turbocharger, which allows the manufacturer 
to maximize the engine performance as well as emission control system. 
The RIA for this proposal provides additional detail on these 
technologies, as well as the Agency's cost analysis for the combination 
of technologies which EPA expects will be used to meet the 2004 
NMHC+NOX standards. Based on the most recent information 
available, the Agency is confident that engine manufacturers are making 
sufficient progress in the development of technologies which will allow 
them to meet the 2004 NMHC+NOX standards. As discussed 
below, the Agency does not believe changes in diesel fuel quality are 
needed for engines to meet these standards.
---------------------------------------------------------------------------

    \37\ SAE paper 973182, ``Advanced Technology Fuel System for 
Heavy-duty Diesel Engines''.
    \38\ Diesel Progress, August 1998, ``CAT Gears Up Next 
Generation Fuel Systems'', available in EPA Air Docket A-98-32, 
Docket Item #II-D-03.
    \39\ Diesel Progress, August 1998, ``Next Generation MEUI-B to 
Debut in 2001'', available in EPA Air Docket A-98-32, Docket Item 
#II-D-03.
    \40\ Diesel Progress, October 1998, ``No Mistaking New Cummins 
ISL Engine'', available in EPA Air Docket A-98-32, Docket Item #II-
D-04.
    \41\ ``Cummins New Midrange Fuel System'', presented by John 
Youngblood, Cummins Engine Company, at the SAE Diesel Technology 
TOPTEC, April 22, 1998, available in EPA Air Docket A-98-32, Docket 
Item #II-D-01.
    \42\ Dickey D.W., T.W. Ryan III, A.C. Matheaus: ``NOX 
Control in Heavy-Duty Engines-What is the Limit?'', SAE paper 
980174, 1998. Dickey; and, Zelenka P., H. Aufinger, W. Reczek, W. 
Cartellieri: ``Cooled EGR-A Key Technology for Future Efficient HD 
Diesels,'' SAE paper 980190, 1998.
    \43\ Kohketsu S., K. Mori, K. Sakai, T. Hakozaki: EGR 
Technologies for a Turbocharged and Intercooled Heavy-Duty Diesel 
Engine,'' SAE paper 970340, 1997; Baert R., D.E. Beckman, A.W.M.J. 
Veen: ``EGR Technology for Lowest Emissions,'' SAE paper 964112, 
1996; and, Heavy-duty Engine Working Group, Mobile Source Technical 
Advisory Subcommittee of the Clean Air Act Advisory Committee, 
``Phase 2 of the EPA HDEWG Program--Summary Document'', available in 
EPA Air Docket A-98-32.
    \44\ See for example SAE paper 981035, ``The Cummins Signature 
600 Heavy-Duty Diesel Engine'' T.R. Stover, D.H. Reichenbach, and 
E.K. Lifferth, Cummins Engine Co., Inc., Feb., 1998.
---------------------------------------------------------------------------

    In addition, as noted in section III.D, the fact that several 
heavy-duty diesel engine manufacturers have agreed to meet the 2004 
standards in 2002 gives the Agency additional confidence that the 
NMHC+NOX standard being reaffirmed in today's proposal is 
appropriate for the 2004 model year.
    As discussed in section IX, and in the draft RIA, EPA does not 
believe more stringent standards for the 2004 model year are 
technologically feasible, giving appropriate consideration to cost, 
energy, and safety factors. Technologies which could reduce emissions 
significantly below the 2004 standards, such as NOX absorber 
catalysts, are still in the research and development stage, and do not 
appear to be ready for the 2004 model year. The Agency has also 
examined technologies to reduce PM from HD diesel engines, including 
diesel oxidation catalysts and particulate traps. As discussed in the 
draft RIA, we believe the current PM standard of 0.1 g/bhp-hr (0.05 for 
urban buses) continues to be the appropriate standard for the 2004 time 
frame. However, in section X of today's proposal we discuss the 
possible feasibility of more stringent standards in later model years, 
although no specific proposals are made today.

B. Are Changes in Diesel Fuel Quality Necessary To Meet the 2004 
Standards?

    The purpose of this section is to assess the current understanding 
of the role diesel fuel quality plays in the ability of diesel engines 
to meet the 2004 NMHC+NOX emission standards and to 
determine whether these standards can be met using currently available 
fuel. It has long been realized that diesel engine technology alone is 
not the only mechanism to lower NOX emissions. Diesel fuel 
quality also plays an important role in emission formation, as well as 
engine performance. In addition, diesel fuel quality can play a role in 
the effectiveness of certain emission control technologies, and in some 
cases can be considered a technology enabler, i.e., some emission 
control devices may not function because of certain diesel fuel 
properties, such as sulfur content. In EPA's 1997 final rulemaking for 
the 2004 standards, we stated that we believed the 2004 standards were 
appropriate and technologically feasible through diesel engine 
technology modifications alone, without changes to diesel fuel quality 
(see 62 FR 54700, Oct. 21, 1997). However, we also stated that this 
issue would be revisited in the 1999 technology review rulemaking. 
``EPA will evaluate in light of any new information whether diesel fuel 
improvements are needed for the standards to be appropriate for 2004.'' 
(See 62 FR 54700, Oct. 21, 1997).
    Section V.A. of this preamble (``2004 Emission Standards for Heavy-
duty Diesel Engines'') and Chapter 3 of the draft RIA for this proposal 
(``Technological Feasibility of HD Diesel and Otto-cycle Standards'') 
discuss in detail the technologies we believe will enable HD diesel 
engines to meet the 2004 standards, on existing U.S. HD diesel fuel. 
These technologies include cooled EGR, advanced fuel injection systems 
with rate-shaping ability, advanced turbocharger designs (such as 
variable nozzle turbochargers), and electronic engine management. These 
technologies have been demonstrated to produce significant emission 
reduction, independent of changes in current U.S. diesel fuel quality. 
Based on the information discussed in section V.A. of this preamble and 
Chapter 3 of the draft RIA, and based on the fact that these emission 
control technologies can produce substantial emission reductions using 
current diesel fuel, we conclude no change in diesel fuel quality is 
necessary to meet the 2004 NMHC+NOX standard. We request 
comment on this conclusion, and encourage commenters to supply any data 
and information that may support their comments.
    Engine manufacturers have recently raised concerns to EPA regarding 
the potential negative effects of current diesel fuel sulfur levels on 
engine durability for 2004 technology engines for the full useful life 
of the engines. As discussed in Chapter 3 of the draft RIA for this 
rule, the use of cooled EGR systems to meet the 2004 standards can give 
rise to potentially significant concentrations of sulfuric acid 
formation in the recirculated exhaust if the EGR system cools the 
exhaust below the water vapor dew point. In addition, some HD diesel 
engine manufacturers have expressed specific concern regarding the 
extended useful life for the heavy-heavy duty diesel service class 
which goes into effect in 2004. In the 1997 final rulemaking for on-
highway heavy-duty diesel engines, EPA revised and extended the useful 
life for the heavy-heavy service class from 290,000 miles to 435,000 
miles (see 62 FR 54700, October 21, 1997). Several manufacturers have 
suggested EPA should reconsider this useful life extension due to their 
concerns with engine durability, diesel fuel sulfur, and cooled EGR 
systems. These manufacturers have suggested EPA implement the extended 
useful life contingent upon federal diesel fuel standards meeting some 
threshold maximum fuel sulfur content. However, the Agency believes 
manufacturers will design cooled EGR systems to limit sulfuric acid 
formation and to prevent in-use durability problems. As

[[Page 58485]]

discussed in the RIA (section 3.II.B), EPA expects engine manufacturers 
to maintain EGR cooler systems slightly above the water vapor dew 
point, particularly at high load. In addition, EPA expects 
manufacturers to utilize EGR systems made of sulfuric acid corrosive 
resistant materials (such as specially treated stainless steel) to 
prevent deterioration of the EGR system. We request additional 
information and supporting data on the manufacturers' concerns 
regarding durability issues associated with the 2004 standards. We 
request specific comment and supporting data on the manufacturers' 
concerns, including any in-use or laboratory durability data, and any 
data which would support or refute the manufacturers' contentions 
regarding the need for a shorter useful life for the heavy-heavy 
service class.
    In the remainder of this section, we review the new information 
which has become available since the 1997 rulemaking through a study 
performed by the Heavy-duty Engine Working Group.
    In anticipation of the need for new information regarding the 
influence of diesel fuel quality on future emission technologies and 
achievable levels, in December of 1995 a new Working Group called the 
Heavy-duty Engine Working Group (HDEWG) was formed under the Mobile 
Source Technical Advisory Subcommittee of the Clean Air Act Advisory 
Committee. The HDEWG consists of approximately 30 members, including 
representatives from EPA, heavy-duty engine original equipment 
manufacturers (OEMs), the oil industry, state air quality agencies, 
private consultants and members of academic institutions. The HDEWG 
formed a steering committee which consisted of representatives from 
EPA, Cummins, Caterpillar, Navistar, Ford, British Petroleum, Equilon, 
Mobil Oil, Phillips, the Engine Manufacturers Association, the American 
Petroleum Institute, and the National Petroleum Refinery Association. 
The HDEWG set as their research objective to contribute to EPA's 1999 
technology review of the NMHC+NOX emission standards for 
model year 2004 heavy-duty diesel engines by assessing relative merits 
of achieving 2.5 g/bhp-hr NMHC+NOX level either through 
engine system modifications alone, or a combination of engine system 
and fuel modifications.
    The HDEWG established a three phase process in order to meet their 
objective. In Phase 1, the goal was to determine whether the combined 
effects of diesel fuel properties on exhaust emissions of ``black 
box'',45 advanced prototype engines being developed by 
engine manufacturers were large enough to warrant a Phase 2. However, 
the details of each black box engine would not be shared with the 
HDEWG. In addition, the HDEWG agreed to use one ``transparent'' engine 
at an independent test facility, Southwest Research Institute (SwRI). 
During Phase 1, testing was to be performed on the transparent engine 
at SwRI, as well as the black box engines at manufacturers' own testing 
facilities, to determine if the transparent engine was representative 
of the black box engines with respect to diesel fuel effects on 
NOX emissions. Phase 2 of the program, which would occur 
upon successful completion of Phase 1, would be used to test a range of 
relevant fuel properties on the transparent engine at SwRI, in order to 
determine the effects of various fuel properties on emissions. Finally, 
Phase 3 of the test program would determine whether or not the results 
seen during Phase 2 on the transparent engine was in fact 
representative of black box engines, i.e., advanced prototype engines 
being developed by engine manufacturers to meet the 2004 standards. 
Phase 3 would be performed at engine manufacturers' laboratories using 
a subset of the fuel matrix from Phase 2.
---------------------------------------------------------------------------

    \45\ ``Black box'' engines are advanced engines being designed 
by engine manufacturers to meet the 2004 standards.
---------------------------------------------------------------------------

    At the time of the publication of this proposal, Phase 1 and Phase 
2 of the program have been completed. Phase 3 is expected to be 
completed by the end of 1999. The RIA for this proposal contains a 
detailed discussion of the Phase 1 and Phase 2 portions of the HDEWG 
test program. The reader should see Chapter 3 of the draft RIA for this 
proposal for a detailed description.
    The HDEWG's primary focus was on the effects of diesel fuel 
properties on HC and NOX emissions, not on PM emissions, and 
therefore fuel sulfur level was not investigated. A significant amount 
of data exists on the effects of diesel fuel sulfur on engine 
emissions, and in fact this data was summarized recently in a paper 
published by members of the HDEWG.46 Existing data on recent 
model year HD engines indicates diesel fuel sulfur level does have a 
statistically significant effect on PM emissions, but no statistically 
significant effect on HC, carbon monoxide (CO), or NOX 
emissions for engines with no exhaust aftertreatment. For this reason, 
and because of the focus on NMHC and NOX emissions, as well 
as the limitations of the prototype SwRI transparent engine, the HDEWG 
did not include fuel sulfur level as a variable in Phase 1, 2 or 3 of 
their test program, nor were PM emissions measured during Phase 1 or 2. 
The Phase 3 test program, done at individual engine manufacturers' 
facilities, will include PM measurement.
---------------------------------------------------------------------------

    \46\ See Lee, R., Pedley, J., and Hobbs, C., ``Fuel Quality 
Impact On Heavy-Duty Diesel Emissions:--A Literature Review'', 
Society of Automotive Engineers paper number 982649, 1998.
---------------------------------------------------------------------------

    The HDEWG concluded two points based on the results of the Phase 1 
testing. First, initial testing on a limited set of diesel fuel 
formulations (fuel batches with high cetane number and low aromatics) 
on advanced prototype engines by the engine manufacturers showed a 
change in NOX emissions which warranted additional testing 
under Phase 2. Second, the ``transparent'' engine at SwRI performed in 
a way that was representative of engine manufacturers' advanced 
prototypes, and was therefore an adequate test engine for Phase 2.
    The purpose of the Phase 2 component of the test program was to 
test a range of relevant fuel properties on the transparent engine at 
SwRI in order to determine the effects of various fuel properties on 
emissions. All testing during Phase 2 of the test program was done at 
SwRI on the transparent engine. Based on the results of the Phase 1 
testing, as well as the literature review performed under Phase 1, the 
HDEWG selected four fuel properties for investigation under Phase 2: 
density, cetane (natural and ``boosted'' 47), monoaromatic 
content and polyaromatic content. As mentioned previously, fuel sulfur 
level was not investigated. A test matrix was designed to decouple 
these fuel properties from each other. The design matrix included two 
levels of density, monoaromatic hydrocarbons, polyaromatic 
hydrocarbons, and three levels of cetane, with duplicate test points 
for both natural and ``boosted'' cetane. The final matrix included 
eighteen test fuels, with density varying from 830 to 860 kg/m\3\, 
cetane numbers from 42 to 48 to 53, monoaromatic content from 10 to 25 
percent, and polyaromatic content from 2.5 to 10 percent. The test 
cycle used by SwRI was the AVL 8-mode test. This steady-state test 
cycle, with associated weighting factors, has been shown in the past to 
correlate very well with NOX emissions measured over the 
U.S. heavy-duty federal test procedure (FTP). All emission tests were 
performed at least in duplicate. The transparent engine used a SwRI is 
a modern, heavy-heavy duty diesel engine with

[[Page 58486]]

electronically controlled unit injectors capable of meeting the U.S. 
1998 model year emission standards. This engine was modified by SwRI 
with the addition of a prototype, low-pressure loop, cooled EGR system 
with manual control of EGR flow rates. For the Phase 2 test program, 
SwRI selected EGR rates necessary to approach an AVL 8-mode composite 
NOX level of 2.5g/hp-hr.
---------------------------------------------------------------------------

    \47\ Boosted cetane is achieved by the addition of a fuel 
additive, in this case ethylhexyl nitrate.
---------------------------------------------------------------------------

    The large quantity of test data generated by the test program was 
evaluated using statistical techniques in order to develop exhaust 
emission and fuel consumption prediction models based on the four fuel 
properties. All properties were evaluated using a significance level of 
five percent. The data generated during Phase 2 indicates that for 
engines utilizing advanced fuel injection and a cooled EGR system 
operating at emissions levels near the 2004 standards the effects of 
large changes in individual fuel properties on HC+NOX 
emissions are rather small, and for cetane number not statistically 
significant. A large decrease in fuel density, from 860 to 830 kg/
m3, or in monoaromatic content, from 25 to 10 percent, is 
predicted to result in a 4.3 percent decrease in HC+NOX 
emissions. A large decrease in polyaromatics content, from 10 to 2.5 
percent, is predicted to result in a 2.3 percent decrease in 
HC+NOX emissions.
    The Phase 2 data was also analyzed to predict the combined effects 
from diesel fuel changes on emissions, not just single property 
changes. The Phase 2 model was used to predict the effect of fuel 
modifications from current, average U.S. on-highway diesel fuel to a 
``cleaner'', reformulated diesel fuel, one with low density (830 kg/
m3), high cetane (52), low monoaromatics (10 percent), and 
low polyaromatics (2.5 percent). The Phase 2 model predicts this 
significant change in U.S. diesel fuel formulation would result in a 
8.4 percent decrease in HC+NOX emissions.
    The Phase 3 results are currently not available. However, based on 
what has been seen in the Phase 1 and Phase 2 portions of this test 
program, we do not believe a change in diesel fuel formulation is 
required to make the 2004 model year NMHC+NOX standards 
technologically feasible and appropriate under the CAA. The data from 
the Phase 1 and 2 portions of the HDEWG does indicate that a change in 
diesel fuel formulation could provide for a small reduction in 
HC+NOX emissions from HD diesels, on the order of an 8 
percent reduction. An assessment of the appropriateness of such a 
diesel fuel reformulation, beyond the 2004 standards with existing HD 
diesel fuel, is outside the scope of this rulemaking.

C. Otto-Cycle Engine-Based Program

    We are proposing an NMHC+NOX standard for Otto-cycle 
engines for 2004 and later model years, but are limiting the 
applicability of this new standard to engines used in vehicles over 
14,000 pounds GVWR and in incomplete vehicles. 48 (We are 
also proposing new vehicle standards for the remaining engines, as 
discussed in later sections.) We are not proposing to apply the vehicle 
standards to these engines at this time. Engines used in incomplete 
vehicles are manufactured for use in many different kinds of heavy-duty 
vehicles by many different manufacturers. Vehicles in the weight 
categories above 14,000 pounds GVWR tend to be quite large and varied 
compared to pick-up trucks and full-size vans, and most dynamometer 
test facilities are currently not equipped to accommodate vehicles in 
this size range. Additionally, this approach is consistent with 
California which allows engine-based testing for these vehicles in its 
Medium-duty Vehicle program.
---------------------------------------------------------------------------

    \48\ Incomplete vehicles less than 14,000 lbs GVWR could 
optionally certify to the proposed new vehicle standards, as 
discussed in a later section.
---------------------------------------------------------------------------

1. Engine Exhaust Emissions Standards
    We propose a NMHC+NOX standard of 1.0 g/bhp-hr for MY 
2004 and later for those Otto-cycle engines in the engine-based 
program. The proposed standard represents a reduction in the 
NOX and HC standards of over 75 percent. EPA believes that 
this standard represents the most stringent standard reasonably 
achievable for these engines, in keeping with the requirements of the 
CAA. EPA's analysis of the technological feasibility of a 1.0 g/bhp-hr 
NMHC+NOX standard is contained in Technological Feasibility 
section below. We also believe that the ABT program proposed for 
engines provides manufacturers with the needed flexibility to meet the 
new standard as their product lines become subject to the new engine 
standards. The ABT provisions are also described below. In their 
assessment of the feasibility of new engine-based standards, engine 
manufacturers recommended a standard of 2.0 g/bhp-hr 
NMHC+NOX. The Technological Feasibility section also 
contains a discussion of the manufacturer's recommendations. EPA 
requests specific comment on a range of possible standards, from the 
proposed standard of 1.0 g/bhp-hr to 1.5 g/bhp-hr, and on the standard 
of 2.0 g/bhp-hr proposed by engine manufacturers.
2. Averaging, Banking, and Trading for Otto-Cycle Engines
    As part of proposing more stringent engine-based standards, EPA is 
proposing a modified ABT program for these engines. The program is 
similar in design to the program adopted for diesel engines. EPA is 
proposing ABT modifications to allow more flexibility within the ABT 
framework to help meet the more stringent standards. ABT credits can 
help manufacturers with engine configurations that are more difficult 
to modify, where more time would help reduce costs. Credits can also 
allow manufacturers to continue with product plans that might call for 
the retirement of an engine family at some point shortly after 2004. By 
banking credits manufacturers can also reduce their uncertainty or risk 
associated with the new standards. In the Summary and Analysis of 
Comments for the Diesel Final Rule, EPA explained why the modified ABT 
program adopted in that rulemaking will not decrease emissions 
reductions associated with the new standards. 49 Similarly, 
EPA believes that the modified ABT program proposed in this rulemaking 
also will not decrease emissions reductions associated with the new 
standards.
---------------------------------------------------------------------------

    \49\ See EPA Air Docket No. A-95-27.
---------------------------------------------------------------------------

    The ABT program has been used for only one Otto-cycle engine family 
to meet the current 4.0 g/bhp-hr NOX standard which went 
into effect in the 1998 model year. In other cases, advances in 
catalyst technology and engine/fuel system improvements have allowed 
manufacturers to meet the standard across their product line. Most 
engine families have certification levels of less than half the 
standard. However, with the proposed standard for 2004, EPA expects ABT 
to become a more important tool for Otto-cycle engine manufacturers.
    An ABT program allows the Agency to propose and finalize a more 
stringent engine standard than might otherwise be appropriate under the 
CAA, since ABT reduces the cost and improves the technological 
feasibility of achieving the standard. EPA is proposing changes to the 
ABT program with the intent that the changes would enhance the 
technological feasibility and cost-effectiveness of the new standard, 
and thereby help to ensure the new standard would be attainable earlier 
than would otherwise be possible. The changes would provide 
manufacturers with additional product planning flexibility and the 
opportunity for a more cost effective introduction of product lines

[[Page 58487]]

meeting the new standard. Also, EPA believes that ABT creates an 
incentive for early introduction of new technology which allows certain 
engine families to act as trail blazers for new technology. This can 
help provide valuable information to manufacturers on the technology 
prior to manufacturers needing to apply the technology throughout their 
product line. This further improves the feasibility of achieving the 
standard. This early introduction can also provide valuable information 
for use in other regulatory programs that may benefit from similar 
technologies (e.g., nonroad programs). EPA views the effect of the ABT 
program itself as environmentally neutral because the use of credits by 
some engines is offset by the generation of credits by other engines. 
However, when coupled with the new standards, the ABT program would be 
environmentally beneficial because it would allow the new standards to 
be implemented earlier than would otherwise be appropriate under the 
Act.
    EPA proposes the following provisions for the modified ABT program 
for Otto-cycle engines:
     Manufacturers could bank NOX credits beginning 
in MY 2000 for MYs 2004 and later.
     Credits would be earned up to a NOX level of 
2.0 g/bhp-hr.
     Credits would be discounted by 10 percent for engine 
families with FELs above the 1.0 g/bhp-hr NMHC+NOX level 
(i.e., the proposed standard) and undiscounted for engine families with 
FELs at or below the 1.0 g cut point.
     For model year 2004 and later, engine families with FELs 
above 0.5
g/bhp-hr NMHC+NOX (i.e., one-half of the proposed standard) 
would be discounted by 10 percent. Engine families with FELs at or 
below 0.5
g/bhp-hr would earn undiscounted credits.
     As with the diesel program, NOX credits banked 
prior to 2004 would be used to meet the combined NMHC+NOX 
standard in 2004 and later.
     Credits banked under the modified program would have 
unlimited credit life.
     Engine families using credits after MY 2004 may not exceed 
the previous NOX standard of 4.0 g/bhp-hr.
     Engine families generating credits prior to 2004 must meet 
the revised requirements for deterioration factors noted above.
    Prior to 2004, manufacturers could continue to use the current ABT 
program. EPA proposes that the current program would end in 2004 and 
the modified program would remain. Only credits banked under the 
modified program could be used in 2004 and later. EPA is proposing to 
end the current program with the 2003 model year because of concern 
that manufacturers could generate enough credits under the current 
program to significantly delay the 2004 standards. The current program 
allows manufacturers to earn credits up to the current NOX 
standard of 4.0 g/bhp-hr. With most engines currently certified with 
NOX levels below 2.0 g/bhp-hr, there is potential for 
substantial credit generation without the application of improved 
technology under the current ABT program. If manufacturers were to bank 
these credits, they could potentially use them to delay the 
introduction of engines meeting the 2004 standards for a large majority 
of their sales for up to three years. The proposed 2.0 g/bhp-hr ceiling 
for credit generation in the modified program provides opportunity for 
manufacturers to earn credits through the use of emissions controls 
that are superior to the average controls currently being used. EPA 
believes this approach is consistent with the goals of ABT. EPA 
requests comment on the proposed 2.0 g/bhp-hr ceiling and on other 
alternatives for transitioning from the current 4.0 g/bhp-hr 
NOX standard to the 1.0 g/bhp-hr NOX standard 
proposed for 2004. One such alternative could be a phase down of the 
credit generation trigger value during the model years prior to 2004, 
rather than a single trigger point of 2.0 g/bhp-hr.
    The changes to credit life and discounting being proposed for Otto-
cycle engines are conceptually consistent with the modifications 
finalized for diesel engines. EPA is proposing to discount credits by 
10 percent if the engine has an FEL above a certain value or cut-point. 
EPA adopted cut points in the diesel program in order to identify the 
introduction of new technology as opposed to recalibrating or enhancing 
existing technology. EPA believes that adoption of cutpoints in the HD 
Otto-cycle engine program will provide similar technology forcing 
incentives. EPA selected cut-point levels which represent a clear step 
in emissions control rather than a marginal emissions reduction. The 10 
percent discount selected for the HD Otto-cycle engine ABT program is 
consistent with the program finalized for diesel engines. In that final 
rule, EPA noted that a 10 percent discount strikes a balance between 
zero (which significantly reduces the incentive to develop and 
implement significantly cleaner technology) and 20 percent (which 
manufacturers indicated in comments was far too large and would create 
a disincentive for the introduction of cleaner technology). (See 62 FR 
54708, October 21, 1997.) EPA requests comment on the selected levels 
of the cut-points and discount adjustment, including comments on 
whether a phased-in approach with a decreasing cut-point would be 
appropriate for this category of engines.
    For diesels, EPA removed the three year credit life limit which 
allows manufacturers to earn credits to be used in 2004 and later as 
early as the 1998 model year. For Otto-cycle engines, MY 2000 will be 
the earliest model year in which the rule would be effective due to the 
timing of the rulemaking. Removing the credit life limit will provide 
an additional year of potential credit banking and allows manufacturers 
to retain credits after 2004 rather than having them expire after a 
certain year. We believe that having credits expire would simply 
encourage manufacturers to use the credits rather than save them; thus, 
removing the credit life limit should provide a net environmental 
benefit.50
---------------------------------------------------------------------------

    \50\ EPA presented a detailed analysis of its ABT program in the 
Summary and Analysis of Comments for the Diesel Final Rule, Docket 
A-95-27, document No. V-C-01.
---------------------------------------------------------------------------

    We believe that our proposals detailed above for a modified ABT 
program will encourage the early use of cleaner technologies and 
provide manufacturers with valuable flexibility in transitioning to 
more stringent standards. EPA is proposing the modification to the ABT 
program in conjunction with the 1.0
g/bhp-hr NMHC+NOX engine-based standards to provide the 
flexibility necessary to enable manufacturers to meet the standard 
across their product line. This flexibility may not be necessary in the 
context of a less stringent standard, in which case the proposed 
modifications to the ABT program might not be supportable. EPA requests 
comments on all aspects of the proposed ABT program.

D. Supplemental Exhaust Emission Standards and Test Procedures for HD 
Diesel Engines

1. Introduction/Background
    EPA's goal is to ensure real-world emissions control over the broad 
range of in-use speed and load combinations that can occur, rather than 
just controlling emissions under certain laboratory conditions. EPA's 
1997 HD diesel rule was based on the expectation that this would be the 
case. The 1997 rule's projected emissions benefit, expected control 
technology, cost, and cost-effectiveness were derived with the

[[Page 58488]]

belief that the engines would be meeting the standards in-use under 
typical operating conditions. The supplemental provisions we are 
proposing today for HD diesel engines are intended to help ensure this 
is the case. Today's proposal includes a new set of supplemental 
emission standards and associated test procedures to more closely 
represent the range of real world driving conditions.
    EPA believes that an important tool for achieving an effective 
compliance program is an in-use program with an objective standard and 
easily implemented test procedure. Today's action does not include a 
proposal for a manufacturer in-use testing program for HD diesels and 
HD Otto-cycle engines. However, as discussed in section V, EPA believes 
a manufacturer in-use testing program is a critical component of a 
comprehensive compliance program, and EPA intends to work with 
interested parties towards the development of a proposal for an in-use 
testing program in the near future. We believe that the combination of 
supplemental standards and an effective in-use testing program will 
ensure that the environmental benefits resulting from the emission 
standards for model year 2004 and beyond will be achieved in-use.
    Historically, EPA's approach to emission standard setting has been 
to set a numerical emission standard on a specified test procedure and 
rely on the prohibition of defeat devices to ensure in-use control over 
the range of operation not included in the test procedure. No single 
test procedure can cover all real world operation or conditions, 
particularly where certification is an engine-based test procedure 
rather than a vehicle-based procedure (i.e., heavy-duty diesel engines, 
heavy-duty Otto-cycle engines used in incomplete vehicles, and heavy-
duty Otto-cycle engines used in vehicles with a GVWR greater than 
14,000 pounds). For example, the same engine used in both a 9,000 pound 
and a 15,000 pound vehicle would likely see much higher speeds and 
loads, on average, in the 15,000 pound vehicle. The defeat device 
prohibition is designed to ensure that emissions controls are employed 
during real world operation and not just under laboratory or test 
procedure conditions. However, the defeat device prohibition is not a 
quantified numerical standard and does not have an associated test 
procedure. As a result, the current focus on a standardized test 
procedure makes it harder to ensure that engines will operate with the 
same level of control in the real world as in the test cell. To ensure 
that emission standards are providing the intended benefits in use, the 
Agency must have a reasonable expectation that emissions under real 
world conditions reflect those measured on the test procedure. The 
supplemental exhaust emission standards and test procedures for HD 
diesel engines are designed to supplement the current FTP standards and 
defeat device prohibition, and help ensure that the standards are 
providing the intended benefits in actual use.
    The Agency also believes a supplemental standard and test procedure 
or an alternative mechanism is needed for HD Otto-cycle engines used in 
incomplete vehicles, and heavy-duty Otto-cycle engines used in vehicles 
with a GVWR greater than 14,000 pounds, in order to assure in-use 
compliance over a broad range of operating conditions. Today's proposal 
does not include supplemental standards for test procedures for this 
class of engines because more information is needed to allow 
determination of appropriate emission levels and resolution of other 
specific technical issues. As discussed in section V, the Agency 
intends to gather further information related to the appropriate levels 
and scope of such standards over the next several months and to release 
a subsequent proposal within the next year which would include 
supplemental standards and test procedures for HD Otto-cycle engines.
    In the Statement of Principles,51 signed by EPA, the 
California Air Resources Board and engine manufacturers, the 
signatories agreed to develop appropriate measures which ensure that 
emission controls are maintained throughout the engine's life. During 
the public comment period for the proposed 2004 standards for diesel 
heavy duty engines, several state and environmental organizations 
advocated establishing an in-use compliance program. (See 62 FR 54707-
54708; October 21, 1997). Commenters urged EPA to develop an effective 
in-use compliance program to ensure that heavy-duty engines comply with 
emission standards over their useful lives. We also received comment 
that the current federal test procedure (FTP) does not reflect 
realistic driving conditions (for example, high speeds and loads), and 
that a more representative test cycle is needed. We acknowledged that 
it was essential to further understand in-use emissions and establish a 
comprehensive in-use compliance presence.
---------------------------------------------------------------------------

    \51\ For more background on the Statement of Principles, see 
section III.A. of this preamble.
---------------------------------------------------------------------------

    In the October 1997 final rule, EPA adopted a number of measures 
designed to improve in-use compliance for heavy-duty diesel engines. 
(See 62 FR 54700-54702; October 21, 1997). In summary, these measures 
included: (1) Extending the engines' useful life; (2) increasing the 
maintenance intervals for emissions-related components; (3) 
strengthening the warranty provisions for emissions defects and 
emission performance; (4) requiring that manufacturers provide owners 
with guidance on maintenance for emissions-related components and on 
responding to emission-related codes from on-board diagnostic systems; 
and (5) strengthening ``anti-tampering'' requirements for engine 
rebuilding. We also committed to further review and revise the 
compliance programs if needed to ensure that the emission reductions 
from more stringent standards are realized in-use. Since then, we have 
learned that many heavy-duty engines currently are not meeting emission 
standards in-use. EPA recently issued enforcement policy guidance to 
partially address this problem.52
---------------------------------------------------------------------------

    \52\ Available in the public docket for review.
---------------------------------------------------------------------------

2. Proposed Supplemental Test Procedures and Standards
    We propose to add two supplemental sets of standards and test 
requirements for HD diesel engines: (1) A supplemental steady-state 
test and accompanying standards; and (2) Not-To-Exceed Limits. Like 
current standards, these new standards would apply to certification, 
production line testing, and vehicles in actual use. All existing 
provisions regarding standards (e.g., warranty, certification, recall) 
would be applicable to these new standards as well. The steady-state 
test is proposed because it represents a significant portion of in-use 
operation of heavy-duty diesel engines that is not adequately 
represented by the FTP. In addition, we are proposing a third 
supplemental test procedure for heavy-duty diesel engines--a Load 
Response Test--as a data submittal requirement only; we do not propose 
emission limits for this test procedure at this time. The proposed Load 
Response Test also represents operation not adequately represented by 
the current FTP (harder accelerations), and could eventually be used to 
ensure effective control of NOX and PM during this type of 
operation. The combination of these supplemental test requirements and 
emission standards would provide assurance that engine emissions are 
designed to achieve the expected level of in-use emissions control over 
all expected operating regimes in-use. These test procedures and 
emission limits are

[[Page 58489]]

described in greater detail in the following sections.
    We believe that to ensure that emission standards actually achieve 
their intended environmental benefits, the emissions measured during 
engine test procedures must be indicative of emissions released during 
real world operation. Recent advances in engine technology have created 
the opportunity for a broader gap to exist between typical real world 
operating conditions and those conditions represented by the current 
EPA test cycle. The inconsistencies between lab and real world 
emissions reduce the certainty that emission standards will achieve 
their intended benefits. One approach to address this is enforcing 
compliance with the current regulations, including the defeat device 
prohibition, on a case-by-case basis. However, as discussed previously, 
given the potential magnitude of the emission impact, we believe it is 
more appropriate to address this concern through expanding the test 
procedures and related emission standards.
    As discussed in more detail in the following sections, each of 
these supplemental proposed emission standards is expressed as a 
multiple of the existing FTP emission standards, or Family Emission 
Limit (FEL) if the engine is certified under the ABT program, whichever 
is applicable. For example, the diesel engine NTE limit for 
NOX + NMHC is 1.25 times the current FTP emission standard, 
or 1.25 times the applicable FEL. When certifying engines under the ABT 
program, manufacturers must ensure that the FEL is set sufficiently 
high so that all of the new proposed emission standards will be met in-
use. For example, there may be cases where the FTP and supplemental 
steady-state emission result is well below the standard, but setting 
the FEL is constrained by the Not-To-Exceed emission result.
    For purposes of certification, actual test data for the steady 
state test and the Load Response Test would have to be submitted as 
part of the certification application (although only the steady state 
test data would require comparison to proposed emission limits). The 
Not-to-Exceed test limits would require only a statement of compliance 
at certification (with supporting details). The compliance statement 
would need to state explicitly that the engine will comply with the 
applicable NTE limits when operated under all conditions which may 
reasonably be expected to be encountered in normal vehicle operation 
and use. However, this statement must be founded upon emission test 
data, additional technical information, and good engineering judgement. 
The manufacturer's basis for making the compliance statement would be 
explained within the certificate application documentation, and the 
supporting information would be available for review by the Agency.
a. Supplemental Steady-State Test
    We propose to add a steady-state test cycle to the current Federal 
test procedures for HD diesel engines. The proposed steady-state test 
cycle is consistent with the test cycle found in the European's ``EURO 
III ESC Test''; however not all aspects of the proposed supplemental 
steady-state test are identical to the EURO III ESC Test.53 
Manufacturers would be required to meet the standards under this test 
cycle as well as continuing to meet the standards using the current 
test procedure (including the current transient test cycle) in 40 CFR 
part 86, subpart N.54 The proposed supplemental steady-state 
test cycle is needed so that the FTP reflects a greater range of 
driving conditions experienced on the road. The current FTP does not 
fully represent the driving patterns of today's heavy-duty diesel 
vehicles, nor does it fully take into account the increased use of 
electronic engine management systems. These electronic systems have the 
ability to optimize fuel economy during real-world driving, but often 
at the expense of emissions. The proposed steady-state test cycle 
represents an important type of modern engine operation, in power and 
speed ranges that are typically used in practice. The mid-speeds and 
mid-to-high loads represented by the proposed steady-state test are the 
speeds and loads that these engines are designed to operate at for 
maximum efficiency and durability. Specifically, highway cruise speeds 
and loads fall into the operation represented by the proposed steady-
state test.
---------------------------------------------------------------------------

    \53\ ``Draft Proposal for a Directive of the European Parliament 
and the Council Amending Directive 88/77/EEC of 3 December 1987 on 
the Approximation of the Laws of the Member States Relating to the 
Measures to be Taken Against the Emission of Gaseous and Particulate 
Pollutants from Diesel Engines for Use in Vehicles'', a proposal 
adopted by the Commission of the European Union on 3 December 1997, 
for presentation to the European Council and Parliament.
    \54\ These requirements are consistent with those in the Consent 
Decrees recently signed with several heavy-duty diesel engine 
manufacturers. (See 63 FR 59330-59334; November 3, 1998).
---------------------------------------------------------------------------

    The proposed supplemental steady-state test cycle consists of 13 
modes of speed and power, covering the typical operating range of 
heavy-duty diesel engines. The cycle concentrates on the engine speed 
range bounded by 50 percent and 70 percent of rated power, which is the 
range most utilized by heavy-duty diesel engines. This speed range is 
then divided into bands (engine speeds A, B and C, as defined in 
proposed Sec. 86.1360-2004(c)). The ``control area'' is defined by the 
area between engine speeds A and C, and between 25 to 100 percent load. 
During the test cycle, the engine is initially run at idle speed, then 
through a defined sequence of 12 modes at various speeds and engine 
loads of 25, 50, 75 and 100 percent. Each mode (except idle) is run for 
two minutes. During each mode of operation, the concentration of the 
gaseous pollutants is measured and weighted (according to the weighting 
factors in proposed Sec. 86.1360-2004(b)(1)). The weighted average 
emissions for each pollutant, as calculated according to this steady-
state test procedure, must not be greater than 1.0 times the applicable 
2004 emission standards. (See proposed Sec. 86.004-11(a)(3).)
    Manufacturers would perform the supplemental steady-state test in 
the laboratory following all applicable test procedures in 40 CFR part 
86, subpart N (e.g., procedures for engine warm-up and exhaust 
emissions measurement). The test must be conducted with all emission-
related engine control variables in the maximum NOX 
producing condition which could be encountered for a 30 second or 
longer averaging period at the given test point.
    In addition to the 13 modes of the test cycle, EPA would have the 
opportunity to select an additional three test points as a check to 
ensure the effectiveness of the engine's emission controls within the 
control area (e.g., ensuring that emissions do not ``peak'' outside of 
the 13-mode test points). This requirement would ensure that an engine 
achieves emissions control throughout the typical operating range. EPA 
would notify the manufacturer of these three additional test points 
prior to the test. During the test, the regulated pollutants would be 
measured at each of these EPA-selected test points. The manufacturer 
also would determine an interpolated value of pollutant emissions at 
each EPA-selected test point, using the measured emissions of the 
closest four adjacent test points. See the illustration in Figure 2 of 
proposed Sec. 86.1360-2004(g). EPA proposes a four-point linear 
interpolation procedure that is consistent with that of the European's 
``EURO III'', referenced above. (See proposed Sec. 86.1360-2004(g)(2).) 
The measured emissions value would then be compared to the interpolated 
emissions value. The measured pollutant value must not exceed the

[[Page 58490]]

interpolated pollutant value by more than five percent. We request 
comment on the proposed interpolation methodology and on whether five 
percent is the appropriate value to use for comparison of interpolated 
values and measured emissions.
    The emission levels at the 12 non-idle test points and the 
calculated emissions values from the four-point interpolation procedure 
for intermediate test points would establish an emissions ``surface'' 
of Maximum Allowable Emission Limits (MAELs), as illustrated in Figure 
1 of proposed Sec. 86.1360-2004(f). This surface would limit emissions 
levels during all normal operations, including transient operation, 
that occur within the control area defined above. Each point on this 
surface will have a MAEL associated with it for all engines in that 
engine family.55 The MAEL for each point is calculated using 
the same four-point linear interpolation procedure used to determine 
the emission value for the EPA test points discussed above. For 
certification, production line and in-use engines, emissions generated 
within the control area may not exceed the MAEL for the corresponding 
speed and load point over a thirty second averaging period.
---------------------------------------------------------------------------

    \55\ The emissions surface would include all points in the 
Supplemental Steady-State control area, as defined above.
---------------------------------------------------------------------------

    At certification, manufacturers would be responsible for testing 
the MAELs by performing the ``check'' described above for the three 
EPA-selected test points. Under its authorities in the Act, EPA could 
determine compliance with the MAELs under any conditions that may 
reasonably be expected to be encountered in normal vehicle operation 
and use, either in the laboratory or in actual use (``on-road''), under 
steady-state or transient conditions, and under varying ambient 
conditions. (See section IV.D.3 for a discussion of on-road testing). 
To determine compliance, test results from operation within the control 
area must comply with the MAEL established for that engine family at 
the same engine speed and load.
b. Not-To-Exceed Limits
    To help ensure that heavy-duty engine emissions are controlled over 
the full range of speed and load combinations commonly experienced in-
use, EPA is proposing to apply Not-To-Exceed (NTE) limits to HDDEs. The 
NTE approach establishes an area (the ``NTE zone'') under the torque 
curve of an engine where emissions must not exceed a specified value 
for any of the regulated pollutants.56 The NTE standard 
would apply under any conditions that could reasonably be expected to 
be seen by that engine in normal vehicle operation and use. In 
addition, we propose that the whole range of real ambient conditions be 
included in NTE testing. The proposed NTE zones, limits, and ambient 
conditions and test procedures for HDDEs and HDGEs are described below. 
These requirements would take effect starting in the 2004 model year 
and would apply to new engines as well as in use throughout the useful 
life of the engine. We request comment on expanding the range of 
ambient conditions in this manner and on whether this expanded range is 
appropriate to begin with the 2004 model year, or whether a phased in 
approach is more appropriate.
---------------------------------------------------------------------------

    \56\ Torque is a measure of rotational force. The torque curve 
for an engine is determined by an engine ``mapping'' procedure 
specified in the Code of Federal Regulations. The intent of the 
mapping procedure is to determine the maximum available torque at 
all engine speeds. The torque curve is merely a graphical 
representation of the maximum torque across all engine speeds.
---------------------------------------------------------------------------

    In addition to helping to ensure emission benefits over the full 
range of in-use operating conditions, the NTE requirements are also 
expected to be an effective element of an in-use testing program. At 
the time of certification manufacturers would have to submit a 
statement that its engines will comply with these requirements under 
all conditions which may reasonably be expected to occur in normal 
vehicle operation and use. The manufacturer must provide a detailed 
description of all testing, engineering analysis, and other information 
that forms the basis for the statement. This certification statement 
must be based on testing and/or research reasonably necessary to 
support such a statement and on good engineering judgement. This 
supporting information would have to be submitted to EPA at 
certification upon request; manufacturers would not necessarily be 
required to submit NTE test data for compliance during certification.
    EPA believes that there are significant advantages to taking this 
sort of approach for heavy-duty engines. The test procedure is very 
flexible so it can represent most in-use operation and ambient 
conditions. Therefore, the NTE approach takes all of the benefits of a 
numerical standard and test procedure and expands it to cover a broad 
range of conditions. Also, with the NTE approach, in-use testing and 
compliance become much easier since emissions may be sampled during 
normal vehicle use. A standard that relies on laboratory testing over a 
very specific driving schedule makes it harder to perform in-use 
testing, especially for engines, since the engines would have to be 
removed from the vehicle. Testing during normal vehicle use, using an 
objective numerical standard, makes enforcement easier and provides 
more certainty of what is occurring in use versus a fixed laboratory 
procedure.
    Even with NTE requirements, EPA believes that it is still important 
to retain standards based on the current heavy-duty engine test 
procedure. This is the standard that EPA expects the certified engines 
to meet on average in use. The NTE testing is more focused on maximum 
limits on emissions for segments of operation or engines used in 
certain applications or geographic regions and should not require 
additional technology beyond what is used to meet the applicable FTP 
standards. EPA believes that basing the emissions standards on a 
distinct cycle and using the NTE zone to help ensure in-use control 
creates a comprehensive program. The existing duty cycle includes low 
speed and low torque operation that are not included in the NTE zone. 
In addition, the standardized test cycle gives a basis for calculating 
credits for use in the averaging, banking, and trading program.
    The NTE requirements for heavy-duty diesel engines are proposed to 
include other provisions including ambient temperature and humidity 
ranges and corrections (discussed below). Start up conditions are 
excluded from NTE testing because start-up is sufficiently covered by 
the cold start in the FTP and would be expected to be significantly 
higher than the proposed NTE limits for a short period of time.
    The NTE test procedure could be run in a vehicle on the road or in 
an emissions testing laboratory using an appropriate 
dynamometer.57 The test itself does not involve a specific 
driving cycle of any specific length (mileage or time), rather it 
involves driving of any type that could occur within the bounds of the 
NTE control area. The vehicle (or engine) would be operated under 
conditions that may reasonably be expected to be encountered in normal 
vehicle operation and use, including operation under steady-state or 
transient conditions and under varying ambient conditions. Emissions 
would be averaged over a minimum time of thirty seconds and then 
compared to the applicable NTE emission limits. The

[[Page 58491]]

applicable ambient conditions and the methodology for correcting 
emissions results for temperature and/or humidity are described in the 
following section. The proposed test procedure can be found in 
Sec. 86.1370-2004 of the proposed regulations. We request comment on 
this test procedure and its applicability to HD diesel engines, 
particularly with respect to whether 30 seconds is an appropriate time 
over which to average emissions for comparison to the emission limits 
for HD diesel engines.
---------------------------------------------------------------------------

    \57\ Likewise, testing to determine compliance with the Maximum 
Allowable Emission Limits could be conducted in the laboratory or in 
a vehicle on the road.
---------------------------------------------------------------------------

    The definition of defeat device is being modified slightly to 
account for the NTE limits. Under the previous definition of defeat 
device, an auxiliary emission control device would not be considered a 
defeat device if it reduced the effectiveness of the emission control 
system under conditions that are substantially included in the federal 
test procedure.
    This definition is less appropriate for the NTE requirements. The 
potential testing surface for the NTE encompasses much of the operating 
range of the vehicle. Therefore, a definition of defeat device that 
would exclude this testing surface would leave little area in which a 
defeat device could be found. This, however, is not the intent of the 
NTE. The NTE is not intended to be the primary emission limit on an 
engine, but is intended instead as a ``no worse than this'' requirement 
that puts an absolute high limit on emissions under most operating 
conditions. It is not supposed to supplant the continuing obligation of 
manufacturers to design their engines without defeat devices. Nor is it 
supposed to provide a cushion for manufacturers to meet a less 
stringent standard off the testing cycles. Therefore, EPA has revised 
the definition of defeat device such that substantial inclusion in the 
federal test procedure does not extend to the NTE zone.
    The proposed NTE zone is illustrated in Figures 1 and 2. With the 
exception of two limited regions under the torque curve (described 
below), the NTE zone for diesels includes all engine operation at or 
above 30 percent of the maximum torque value of the engine and all 
engine operation at or above a specific engine speed calculated based 
on the maximum power of the engine.58 This zone covers the 
areas of operation that are of most concern to the Agency from an 
environmental perspective. Because engines do not operate frequently at 
speeds that occur below the maximum torque peak (heavy-duty diesel 
engines generally operate at speeds near or above their maximum 
torque), the emissions generated from operation at lower speeds are 
relatively insignificant. The same is generally true of operation at 
below 30 percent of maximum torque--heavy-duty diesel engines do not 
spend much time in this region and the emissions generated in this 
region of operation tend to be less of a concern for the Agency. 
Manufacturers are still forbidden from using defeat devices both inside 
and outside the NTE zone, however.
---------------------------------------------------------------------------

    \58\ The maximum torque value and maximum power of the engine 
are derived as part of the engine mapping procedures specified in 40 
CFR 86.1332.
---------------------------------------------------------------------------

    For the reasons described below, two small regions are excluded (or 
``carved out'') from the NTE zone defined above. First, we propose to 
exclude from the NTE zone the area under the torque curve that falls 
below the curve representing 30 percent of the maximum power value of 
the engine (as distinguished from maximum torque). This excluded region 
contains low engine speed and torque operation for which we believe 
current heavy-duty engines spend an insignificant portion of their 
operating lives. In addition, at low loads and low-to-mid speeds (low 
total power), the measurement of grams per brake-horsepower emissions 
tends to balloon, even while emissions go down. This region is proposed 
to be carved out for all pollutants.
    Second, a PM-specific region is ``carved out'' of the NTE control 
area. The PM-specific area of exclusion is generally in the area under 
the torque curve where engine speeds are high and engine torque is low, 
and can vary in shape depending upon several speed-related criteria and 
calculations detailed in the regulations. Controlling PM in this range 
of operation presents fundamental technical challenges which we believe 
cannot be overcome in the 2004 time frame. Specifically, the cylinder 
pressures created under these high speed and low load conditions are 
often insufficient to prevent lube oil from being ingested into the 
combustion chamber. High levels of PM emissions are the result. 
Furthermore, we do not believe that these engines spend a significant 
portion of their operating time in this limited speed and torque range.
    The definition of the proposed NTE zone and the carve-out areas 
strives to place an effective cap on emissions over a broad area of in-
use operation that includes the types of operation that are of the 
greatest environmental concern. The definition of the control area, the 
carve-outs, and the emissions limit must all be balanced to achieve the 
Agency's goals. We believe that the combination of the proposed zone 
and the proposed emission limits within the zone effectively accomplish 
the Agency's goals of ensuring that emissions are controlled over a 
wide range of in-use operation. We request comment on the proposed zone 
and emission limits.
    Examples of the NTE zone, including the areas excluded from the 
zone, are shown below in Figures 1 and 2. The A, B, and C engine speeds 
are the same as those defined for the advanced steady state test and 
described above and in the proposed regulations. Note that there are 
two possible constructions of the PM ``carve-out'' detailed in the 
draft regulatory language. The example in Figure 1 shows the PM carve-
out as it would look if the C speed is below 2400 revolutions per 
minute (rpm), while Figure 2 shows the construct of the PM carve-out if 
the C speed is above 2400 rpm.
BILLING CODE 6560-50-P

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[GRAPHIC] [TIFF OMITTED] TP29OC99.000



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[GRAPHIC] [TIFF OMITTED] TP29OC99.001



BILLING CODE 6560-50-C

[[Page 58494]]

    Within the NTE zone, EPA proposes that emissions of each of the 
regulated pollutants (NMHC+NOX, CO, PM), when averaged over 
a minimum time of 30 seconds, must not exceed 1.25 times the applicable 
FTP standards (or FEL if ABT is used). A minimum 30 second average is 
proposed to ensure that a short transient does not produce high 
results. This 30 second sampling period should be long enough to allow 
an emissions spike to be averaged out while still retaining a short 
enough period to look at a specific type of operation. In addition, EPA 
proposes that within the NTE zone smoke and opacity must not exceed 
either a filter smoke limit of 1.0 (on the Bosch smoke number scale) or 
a thirty second average smoke opacity of four percent for a five inch 
path for transient testing and a ten second average smoke opacity of 
four percent for a five inch path for steady state testing.
c. Diesel Supplemental Load Response Test
    Today we are also proposing a Supplemental Load Response Test (LRT) 
for heavy-duty diesel engines. This supplemental test is intended to 
represent a specific type of engine operation--rapid transient 
acceleration--that is not adequately represented in the current 
transient test procedure. Although the current transient test cycle 
does contain numerous transient operations, these transients are 
limited to the engine operating range exercised during the current FTP, 
not the broader range of operation which is covered by the Supplemental 
Load Response Test. Specifically, the Supplemental Load Response Test 
is intended to address diesel engine emissions performance during rapid 
transient accelerations from any speed within the NTE zone. As 
proposed, the test focuses on quantifying PM and NOX 
emissions during the portion of a truck's operation where it 
accelerates rapidly and where certain engine emission controls can be 
inadequate. In addition, this type of operation can often produce 
visible smoke, which is frequently noticed by the public and can 
influence their opinions about the cleanliness of diesel engines.
    We are not proposing specific emission limits for this test 
procedure at this time. Rather, we are proposing that manufacturers of 
heavy-duty diesel engines submit test results as part of their 
application for EPA certification. The test results to be submitted at 
certification would include testing, at a minimum, at a several engine 
speeds specified in the proposed regulations. As noted in section 
III.D, the Consent Decrees with most of the heavy-duty diesel engine 
manufacturers establish target limits for the Load Response Test of 1.3 
times the FTP standard for NMHC+NOX and 1.7 times the FTP 
standard for PM. We believe that these limits may be appropriate and 
technologically feasible, but we also recognize that under the Consent 
Decrees there is a process of data collection and evaluation that could 
result in modifications to these limits sometime in the latter half of 
the year 2000. The data submittal requirements proposed today are 
consistent with the requirements in the Consent Decrees.
    We believe that establishing a future Load Response Test with 
appropriate emission limits may be a valuable addition to EPA's 
compliance program, particularly for in-use on-road testing using the 
equipment specified in a later section of this document, and when the 
process of evaluating the available data is complete we intend to 
evaluate the addition of specific Load Response Test emission limits to 
EPA's compliance program in a future supplemental proposal. The 
proposed data submittal requirement would enable a better understanding 
of the emissions that occur under this type of operation and would 
ensure that EPA establishes robust standards in a future action. Such a 
future action would consider including a requirement that manufacturers 
submit a statement of compliance at certification (similar to the 
approach proposed today for the NTE emission limits). We request 
comment on the proposed approach to a Load Response Test, as well as on 
the possibility of adding appropriate emission limits and certification 
requirements with a later action.
    The test procedure as proposed is relatively straightforward. The 
engine fuel control is moved rapidly to the full fuel position and held 
at that point for a minimum of two seconds. As proposed, this sequence 
would be carried out in a laboratory environment at a constant speed 
setting, but in the future testing could be conducted using on-road 
equipment specified in a following section, in which case the vehicle 
speed would depend upon the characteristics and response of the vehicle 
being tested. The proposed regulations specify six different speeds, 
ranging from the lowest speed in the NTE control area to a high speed 
defined according to a calculation specified in the proposed 
regulations. The test sequence could be repeated if necessary to obtain 
an adequate sample for analysis (e.g., in the event that one cycle is 
inadequate for collecting enough particulate mass for gravimetric 
analysis). Although this could conceivably be carried out in several 
different ways, we encourage the use of methodologies that adequately 
represent the transient operation that is the true emphasis of this 
test procedure. The proposed test procedure can be found in proposed 
Sec. 86.1380-2004.
d. Ambient Conditions, Temperature and Humidity, Laboratory and In-Use 
Testing
    As stated above, our goal is to create a program that will ensure 
emission control over a wide range of in-use conditions, including 
ambient temperature and humidity. The FTP and Supplemental Steady State 
tests are laboratory-based test procedures that would be conducted 
under standard laboratory ambient conditions defined in the 
regulations, with emission results corrected according to existing 
regulations regarding laboratory testing procedures.59 The 
NTE and verification of compliance with the Maximum Allowable Emission 
Limits could be conducted in the laboratory or during on-the-road 
driving, and the standards associated with these tests, where 
applicable, are proposed to apply under any ambient conditions. Within 
proposed temperature and humidity ranges, emissions from heavy-duty 
diesel engines must meet the requirements described above, without 
corrections for temperature and humidity. For situations in which the 
ambient conditions are outside these ranges, EPA proposes that 
NOX be corrected for humidity and both NOX and PM 
be corrected for temperature. Corrections would be to the end of the 
specified temperature or humidity range nearest the actual ambient 
conditions. We request comment on applying this expanded range of 
ambient conditions to the new supplemental test procedures, and on 
whether implementation of an expanded range should apply starting with 
the 2004 model year or some later model year.
---------------------------------------------------------------------------

    \59\ The acceptable temperature range for FTP testing is defined 
by regulation as 68-86 degrees Fahrenheit. There is no specified 
humidity range, but NOX emission results are to be 
corrected to 75 grains of water per pound of dry air.
---------------------------------------------------------------------------

    For emission results to be compared to the NTE emission limits, we 
propose that the temperature range be from 55 to 95 degrees Fahrenheit 
(12.8 to 35.0 degrees Celsius) and that the humidity range be from 50 
to 75 grains of water per pound of dry air (7.14 to 10.71 grams of 
water per kilogram of dry air). The proposed temperature range 
encompasses the conditions exhibited by most days on which an 
exceedance

[[Page 58495]]

of the ozone NAAQS is observed. 60 In addition, EPA analyses 
pertaining to a recent rulemaking effort concluded that the ``typical'' 
ozone nonattainment day exhibits a maximum temperature between 90 and 
95 degrees Fahrenheit. (See 61 FR 54852, October 22, 1996). The 
relative humidity range being proposed today reflects the current 
understanding of humidity corrections, in that higher humidity 
typically results in lower NOX levels. Therefore, 
NOX test results from a truly hot and humid day (e.g., a 
``typical'' ozone exceedance day where the maximum temperature is in 
the 90's and the humidity is about 100 grains of water per pound of dry 
air, or 40 percent relative humidity) would be adjusted upward by the 
correction factor when correcting back to the drier conditions of the 
specified range, thus providing environmental protection during hot and 
humid conditions typical of ozone exceedance days. For emission results 
to be compared to the Maximum Allowable Emission Limits we propose that 
NOX emissions be corrected to a standard level of 75 grains 
of water per pound of dry air and that NO X and PM emissions 
be corrected to the nearest endpoint of the range from 68 to 86 degrees 
fahrenheit if tested outside this range. The proposed corrections for 
verifying compliance with the Maximum Allowable Emission Limits would 
correct emission results to standard laboratory conditions used for FTP 
testing because these emission limits are derived from testing under 
the standard laboratory conditions. We request comment on these 
proposed ranges.
---------------------------------------------------------------------------

    \60\ Memorandum, Mark Wolcott, EPA, to Charles L. Gray, EPA, 
``Ambient Temperatures Associated With High Ozone Concentrations,'' 
September 6, 1984. Available in the public docket for review.
---------------------------------------------------------------------------

    At this time, EPA is working with HD diesel engine manufacturers on 
developing humidity and temperature correction factors. In the future, 
it is EPA's intent to adopt the correction factors that are developed 
through this effort. Because the correction factors are not yet 
developed, EPA proposes only that good engineering judgement be used 
when correcting for humidity and temperature outside of the proposed 
ranges.
3. Access to On-Board Computer Information
    Modern HD diesel and gasoline engines make extensive use of 
electronics for engine control and management. HD engines make 
extensive use of on-board computers for fuel system control, and other 
emission-related component control, which in the future will likely 
include cooled EGR systems on HD diesel engines. Many of these newer 
systems make use of Controller Area Networks as a means of 
communicating information from the on-board electronic control module 
(ECM) to other on-board sensors and control devices (such as fuel 
injectors, rail pressure for common rail systems, boost-pressure 
sensors, coolant level sensors, coolant temperature sensors). These on-
board systems control many aspects of emission related components, 
including fuel and air management components. EPA is concerned that 
electronic controls (or any other Auxiliary Emission Control Devices) 
not be used in such a way as to result in higher emissions from HD 
engines in use than would be seen during certification or laboratory 
testing. Therefore, EPA must have access to this information. We are 
proposing that, upon request from EPA, engine manufacturers must 
provide to EPA hardware and/or documentation necessary to read and 
easily interpret (in engineering units if applicable) any information 
broadcast by on-board computers and ECM's which relate in anyway to 
emission control devices and auxiliary emission control devices (AECD). 
This proposed requirement includes access to proprietary code 
information which could not otherwise be interpreted by parties other 
than the engine manufacturer, EPA would retain any legitimate 
confidential business information as such. This requirement could 
include the delivery, upon request from EPA, from the manufacturer to 
EPA the most up to date scantool hardware used by the engine 
manufacturer for monitoring, interpreting, and recording all emission 
related electronic input and output data broadcast on an engine's on-
board controller network. The requirement could also include access to 
passwords which would enable a generic scan tool or personal computer 
to read and interpret proprietary codes, if such passwords exist. EPA 
requests comment on these requirements.

E. Otto-Cycle Vehicle-Based Program

    Heavy-duty Otto-cycle vehicles can be split into two groupings, 
complete and incomplete vehicles. Complete vehicles are those that are 
manufactured with their cargo carrying container attached. Complete 
vehicles consist almost entirely of pick-up trucks, vans, and sport 
utility vehicles and account for about 75 percent of all Otto-cycle 
heavy-duty vehicle sales. All complete vehicles are currently below 
14,000 pounds GVWR. Incomplete vehicles are those chassis that are 
manufactured without their cargo carrying container attached. These 
chassis may or may not have a cab attached. The incomplete chassis are 
then manufactured into a variety of vehicles such as recreational 
vehicles, tow trucks, dump trucks, and delivery vehicles. Currently, 
there are three original equipment manufacturers (GM, Ford, and Daimler 
Chrysler) of heavy-duty Otto-cycle engines and they also manufacturer 
all of the complete vehicles in which those engines are 
used.61 These manufacturers also manufacture most incomplete 
chassis equipped with Otto-cycle engines.
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    \61\ There are also aftermarket alternative fuels conversion 
manufacturers, as discussed in section E.7, below.
---------------------------------------------------------------------------

    Currently, EPA requires heavy-duty engines to be tested to engine-
based standards. Light-duty vehicles and light-duty trucks are required 
to be tested over a vehicle-based test commonly known as the light-duty 
federal test procedure, or FTP. Heavy-duty vehicle manufacturers have 
the option of testing heavy-duty vehicles up to 14,000 pounds GVWR over 
the light-duty FTP to light-duty truck standards (EPA ``heavy-as-
light'' testing provisions), rather than to EPA engine-based standards.
    As part of their medium-duty vehicle program, California requires 
complete Otto-cycle vehicles between 8,500 and 14,000 pounds to be 
certified to vehicle-based standards rather than engine-based 
standards. Manufacturers test the vehicles in essentially the same 
manner light-duty trucks are tested. California has established Low 
Emission Vehicle (LEV and LEV-II) standards for these vehicles. In the 
MDV program, engines used in incomplete vehicles and vehicles above 
14,000 pounds may be certified to engine-based standards rather than 
vehicle standards. Diesel powered vehicles are also allowed to be 
certified to engine-based standards as an alternative to the vehicle 
standards, and in fact, most if not all manufacturers choose the 
engine-based standards for their diesels.
    Today's proposal recognizes that manufacturers have found the 
option to certify diesel vehicles to the California chassis-based 
standards not particularly useful, and as a result the ability to 
certify diesels to the chassis-based standards proposed below is not 
included in the proposal. However, we request comment on this issue, 
and if this option is indeed a desirable one, we would add the 
California MDV PM standard of 0.12 grams/mile to the regulations for 
manufacturers that select this option. In addition, we request comment 
on the possibility of requiring

[[Page 58496]]

complete diesel heavy-duty vehicles under 14,000 pounds GVWR to be 
subject to chassis-based standards, and if so, whether the standards 
proposed for complete Otto-cycle vehicles or some other set of 
standards (perhaps the proposed Otto-cycle standards adjusted by an 
appropriate factor) would be appropriate for chassis-certified heavy-
duty diesel vehicles.
1. Moving to a Vehicle-Based Test Procedure and Standards
    EPA proposes to adopt vehicle-based standards and test procedures 
for complete Otto-cycle vehicles between 8,500 and 14,000 pounds GVWR. 
As in the California MDV program, these complete vehicles would be 
tested on the federal light-duty vehicle and light-duty truck test 
procedure.62 EPA believes this approach is reasonable and 
offers several advantages over engine-based testing. In addition, EPA 
is proposing to refine the program further by incorporating some 
complete Otto-cycle vehicles between 8,500 and 10,000 pounds GVWR into 
the Tier 2 program proposed earlier this year (see Section IV.F for 
details regarding this aspect of the proposal). Many of the full size 
pick-up trucks, vans, and sport-utility vehicles which have a GVWR 
above 8,500 pounds are often used by owners for personal 
transportation, and a chassis-based test procedure incorporating the 
light-duty FTP cycle is representative of this type of transportation 
and operation. The harmonization of test procedures with California 
allows for certification data to be used for both federal and 
California certification requirements, reducing the testing burden for 
manufacturers. In addition, because vehicle testing is less resource 
intensive than engine testing, EPA and manufacturers will be better 
able to conduct in-use testing to verify emissions compliance.
---------------------------------------------------------------------------

    \62\ Test procedures contained in 40 CFR Part 86 subpart B, 
excluding the Supplemental FTP.
---------------------------------------------------------------------------

    In developing the proposal, EPA met with a number of stakeholders 
and during these discussions several stakeholders supported EPA's 
consideration of a chassis-based program, similar to California's MDV 
program.63 Manufacturers presented EPA with a proposal for a 
chassis-based program after EPA expressed its substantial interest in 
moving to chassis-based testing. Manufacturers expressed interest in 
EPA's adoption of a program that would allow them to use one set of 
certification information for both California and EPA. Other 
stakeholders were also supportive of the move to a chassis-based 
requirement due to the benefits noted above.
---------------------------------------------------------------------------

    \63\ Stakeholders involved in these discussions included 
representatives from states, environmental groups, emission control 
equipment manufacturers, and engine manufacturers. See Docket A-95-
27, IV-E, for more information on these discussions.
---------------------------------------------------------------------------

2. Vehicle Exhaust Emissions Standards
    EPA proposes to adopt the chassis-based standards contained in 
Table 4 below for model years 2004 and later. The numeric levels were 
selected to match the full life emissions standards in place for 
California's MDV program for LEV vehicles above 8,500 pounds GVWR. The 
standards would apply to complete vehicles in the weight categories 
shown. The standards are for emissions over the FTP and vehicles would 
be tested at adjusted loaded vehicle weight (ALVW), also known as test 
weight (TW).64
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    \64\ ALVW or TW is the actual weight of the vehicle, known as 
curb weight, plus half pay load. Its also the average of the curb 
weight and GVWR, which is curb weight plus full pay load.

                 Table 4.--EPA Proposed Full-Life Emission Standards Model Years 2004 and Later
                                                [Grams per mile]
----------------------------------------------------------------------------------------------------------------
                                                                    Nonmethane
                 Vehicle weight category (GVWR)                     organic gas         NOX             CO
                                                                      (NMOG)
----------------------------------------------------------------------------------------------------------------
8,500-10,000 lbs*...............................................            0.28             0.9             7.3
10,001-14,000 lbs...............................................            0.33             1.0             8.1
----------------------------------------------------------------------------------------------------------------
*Excluding those vehicles covered by the proposed Tier 2 program, as described in Section IV.F of this proposal.

    We believe that these proposed standards reflect the most stringent 
standards achievable for the 2004 model year, considering cost and 
other appropriate factors, and are therefore consistent with the 
requirements of the CAA. As discussed in the Technological Feasibility 
section below, LEV technologies are being required in California 
beginning in 1998 and will be fully phased in beginning in 2004. By 
harmonizing the federal and California standards, this proposal would 
allow manufacturers to take advantage of the research and development 
that they have undertaken to meet the California requirements. While it 
is true that a small percentage of vehicles that have not been offered 
for sale in California would, under the proposal, be required to meet 
lower vehicle standard, EPA believes that the decision not to market 
such vehicles in California was typically related more to their very 
small sales volumes rather than for technological reasons. 
Manufacturers would have some flexibility in meeting the standards, and 
therefore some capability to deal with issues such as this, by today's 
proposal to apply an ABT program to heavy-duty Otto-cycle vehicles.
    In a recent NPRM, we proposed to reduce the sulfur in federal test 
fuel to reflect the reductions in sulfur we proposed for commercial 
gasoline.65 Currently, federal test gasoline is subject to a 
limit of 0.10 percent sulfur by weight. We proposed to amend that to an 
allowable range of 30 to 80 ppm (0.003 to 0.008 percent by weight). We 
also proposed that vehicles be certified and in-use tested using 
federal test fuel. However, where vehicles are certified for 50 state 
sale, and where other testing issues do not arise, we proposed to 
accept for purposes of certification the results of testing done for 
California certification on California Phase II fuel, but we would 
reserve the right to perform or require in-use testing on federal fuel. 
Where vehicles are only certified for non-California sale, we proposed 
to require certification and in-use testing on federal fuel. These 
provisions, if finalized as proposed, would apply to heavy-duty 
vehicles certified to the chassis-based provisions in this proposal.
---------------------------------------------------------------------------

    \65\ 64 FR 26003, May 13, 1999, ``Control of Air Pollution From 
New Motor Vehicles: Proposed Tier 2 Motor Vehicle Emissions 
Standards and Gasoline Sulfur Control Requirements''.
---------------------------------------------------------------------------

    EPA is proposing a hydrocarbon standard in the form of nonmethane 
organic gas (NMOG) in order to be consistent with California's MDV 
standards. EPA proposes to also accept hydrocarbon emissions in the 
form of NMHC or total hydrocarbons (THC) in

[[Page 58497]]

lieu of NMOG, These are forms of hydrocarbon standards which are the 
standards typically used by EPA under the heavy-duty Otto-cycle control 
program. Accepting emissions in these various forms provides 
manufacturers with additional flexibility since establishing NMOG 
levels can be more complex than NMHC or total hydrocarbon levels. 
Manufacturers submitting California certification data would submit 
NMOG emissions data due to California requirements.
    The vehicle manufacturer would be responsible for determining 
whether a vehicle is a complete vehicle and subject to the vehicle-
based standards or an incomplete vehicle and subject to engine-based 
standards. The manufacturer would make this determination based on the 
definition of incomplete vehicle described above. The vehicle 
manufacturer may request a determination from EPA when the status of a 
specific vehicle model is unclear. Manufacturers of complete vehicles 
are responsible for vehicle emissions certification, as is the case 
currently in EPA light-duty vehicle programs. More details on vehicle 
compliance are provided in section E.5 below. Although currently 
uncommon in this segment of the market, a vehicle manufacturer may 
purchase engines from another manufacturer to place in incomplete 
vehicles. In such cases, the vehicle manufacturer would be responsible 
for ensuring that the engines they purchase have been emissions 
certified to EPA's engine-based standards by the engine manufacturer. 
The engine manufacturer would be responsible for the engine 
certification and emissions performance of the engines, as is the case 
currently in EPA's engine programs.
    The approach EPA is proposing is based on the technological 
feasibility of extending the use of LEV technologies from California to 
nationwide use in the 2004 MY time frame. The standards selected are 
based on the capabilities of technologies designed to meet the LEV 
standards. The approach of allowing the option of using California 
certification data is intended to avoid duplication of effort for the 
manufacturers. EPA requests comments on the proposed approach for 
chassis-based testing and the proposed standards.
3. Heavy-Duty Vehicle Averaging, Banking and Trading
a. Background
    Averaging, Banking, and Trading is a long-established mechanism 
allowing the Agency to propose and finalize a more stringent standard 
than might otherwise be appropriate under the CAA, since ABT reduces 
the cost and improves the technological feasibility of achieving the 
standard. Manufacturers are able to bank credits by certifying some 
engine families to emissions levels lower than applicable standards. 
The credits may be banked and then used to certify other engine 
families to levels higher than the emissions standards. For HD Otto-
cycle engines, ABT is available for meeting NOX standards. 
Under the current ABT program, banked credits are discounted by 20 
percent and have a three year life, after which they 
expire.66
---------------------------------------------------------------------------

    \66\ With ABT, manufacturers are able to establish a Family 
Emissions Limit (FEL) for an engine family which becomes the 
standard for that family. Manufacturers earn or use credits based on 
the difference between the FEL and the applicable standard. A full 
overview of the ABT program is contained in EPA's 1996 NPRM, 61 FR 
33451.
---------------------------------------------------------------------------

    In the final rule for diesel engine standards for MY 2004 and 
later, EPA modified the ABT program for diesel engines with the intent 
that the changes would enhance the technological feasibility and cost-
effectiveness of the new standard, and thereby to help to ensure that 
the new standard would be attainable earlier than would otherwise be 
possible.67 EPA reduced the discount rate to 10 percent and 
established a cut point under which an engine family would earn 
undiscounted credits. Also, EPA removed the three year credit life 
limit which allows manufacturers to earn credits to be used in 2004 and 
later as early as the 1998 model year. EPA modified the HD diesel ABT 
program, among other reasons, because the Agency believes that the 2004 
and later standards are stringent technology-forcing standards and the 
additional flexibility would improve the manufacturer's ability to 
comply with the standards cost effectively and in a manner that would 
not disrupt product planning.68 EPA did not adopt the 
modified program for Otto-cycle engines at that time, however, because 
the Agency did not finalize the proposed standards for Otto-cycle 
engines.
---------------------------------------------------------------------------

    \67\ 62 FR 54694, October 21, 1997.
    \68\ For a more complete discussion of the ABT provisions 
relating to the 2004 model year heavy- duty diesel engine standards, 
see Summary and Analysis of Comments: Control of Emissions of Air 
Pollution from Highway Heavy-Duty Engines, September 16, 1997, EPA 
Air Docket A-95-27, Doc. No. V-C-01.
---------------------------------------------------------------------------

    The CAA requires that EPA set emission standards with appropriate 
consideration to feasibility and cost. We believe that the ABT programs 
in today's proposal are appropriate in the context of the technical 
feasibility and the cost of the proposed emission standards. For all of 
these reasons, we are proposing an ABT program for the vehicle-based 
standards.
b. Proposal
    EPA is proposing separate averaging, banking, and trading programs 
for vehicles certified to the vehicle-based standards and engines 
certified to the engine-based standards. This section addresses the 
proposed ABT program for the vehicle-based standards. The proposed 
engine-based ABT program is discussed above in section IV.C. EPA is 
also requesting comment on the possibility of allowing credit exchanges 
between the engine and vehicle ABT programs. This issue is discussed 
below in the following section.
    For vehicles, EPA proposes an ABT program structured similar to the 
modified ABT program described above for engines. EPA proposes the 
following provisions:
     Beginning in 2000, manufacturers could bank vehicle-based 
credits by choosing to certify vehicles rather than engines
     Manufacturers would earn NOX credits up to the 
applicable 2004 NOX standard by establishing an FEL below 
the 2004 standard
     Vehicles with FELs at or below 0.6 g/mile NOX 
would earn undiscounted credits, engines with FELs above 0.6 g/mile 
would earn credits discounted by 10 percent
     2004 and later model year vehicles using credits may not 
exceed a NOX level 1.53 g/mile
     Heavy-duty Otto-cycle vehicles would be a single grouping 
or averaging set.
    EPA recognizes that manufacturers would be required to achieve 
NOX levels lower than the proposed 2004 NOX 
standards in order to generate credits prior to 2004, and that this 
aspect of the program differs from the proposed program for engines. 
Based on current vehicle certification data from the California LEV 
program, some vehicle models have demonstrated the potential for very 
low NOX emissions in the 0.2 to 0.5 g/mi range. We believe 
there would be the potential for credit generation in the proposed 
program if similar technologies were used nationwide prior to 2004. In 
addition, manufacturers are required to meet the proposed standards in 
California prior to 2004 and therefore will be well on their way to 
transitioning to the standards. They are already designing vehicles to 
meet the standards in California. Therefore, the importance of banked 
credits is likely to be diminished for vehicles compared to engines.

[[Page 58498]]

    The ABT program can help manufacturers certify especially difficult 
or low volume applications and help manufacturers comply across their 
full product line without having to restrict vehicle offerings. The 
Agency believes the proposed program offers sufficient flexibility in 
light of the technology and cost requirements associated with the 
proposed standards. Based on current certification data and 
technological capabilities we believe manufacturers will have 
opportunities to generate credits to help with meeting the proposed 
2004 standards. Moreover, because these standards are required in 
California for several model years prior to 2004, EPA does not expect 
feasibility issues with the vast majority of vehicle models.
c. Credit Exchanges Between the Engine and Chassis-Based Programs
    We believe that credit exchanges between the separate engine and 
chassis-based ABT programs might be appropriate, as well as desirable 
for manufacturers, but unresolved concerns and issues (described below) 
prevent a proposal to allow such exchanges at this time. If these 
concerns can be addressed prior to the final rulemaking we will 
consider finalizing provisions allowing credit exchanges between the 
two ABT programs. Specific concerns include derivation of engine and 
vehicle-specific conversion factors, the possibility of large 
quantities of credits effectively delaying the introduction of cleaner 
vehicles and/or engines, and the method for exchanging vehicle-based 
NOX credits with engine-based NMHC+NOX credits 
(or vice versa), and whether the emissions standards would continue to 
be appropriate if such a broader credit exchange program was allowed.
    The chassis-based ABT program is based on emissions in units of 
grams per mile (g/mi) and the engine ABT program is based on emissions 
in units of grams per brake horsepower-hour (g/bhp-hr). Consequently, 
trading credits between the two programs would require a conversion 
factor. Although the Agency uses conversion factors to estimate g/mi 
emissions based on g/bhp-hr emissions rates for purposes of emissions 
inventory modeling, these conversion factors are estimates of a fleet 
average, not an engine- or vehicle-specific conversion factor. There is 
considerable variation in the conversion factors from vehicle to 
vehicle. Also, conversion factors that have been previously derived 
don't necessarily predict emissions over the specific test cycles. Both 
the emission standards and the ABT credits are based on emissions over 
specific test cycles. Conversion factors developed for specific engines 
and vehicles on specific test cycles could vary widely from an 
``average'' conversion factor. EPA believes that vehicle and engine 
test cycle specific conversion factors would be needed in order to 
allow transfers of credits between the two Otto-cycle ABT programs.
    In general, EPA believes that provisions allowing the exchange of 
credits between the two Otto-cycle ABT programs should include a 
conversion factor for each engine family for which the manufacturer 
intends to develop transferable credits. Each conversion factor would 
likely have to be based upon a number of engine and vehicle tests, and 
would have to be approved by EPA prior to use. To ensure adequate 
emissions control, EPA would consider requiring the conversion factors 
to be developed by testing engines and vehicles expected to generate 
``worst-case'' emissions. EPA requests comment on how to structure a 
program that manufacturers would be required to use to develop 
appropriate conversion factors for each engine family.
    The ability to trade credits between the engine and chassis-based 
ABT programs is not needed prior to the 2004 model year and would 
unnecessarily complicate the ABT programs, for the following reasons. 
Prior to the 2004 model year, EPA emission standards for heavy-duty 
Otto-cycle vehicles are engine-based standards. Absent any credit 
exchange provisions, manufacturers could still generate vehicle-based 
credits by voluntarily certifying engines to the vehicle-based program. 
These provisions already provide the flexibility for manufacturers to 
decide how many engine-based and vehicle-based credits to generate.
    Manufacturers will have the opportunity to generate Otto-cycle 
engine-based credits prior to the 2004 model year due to the structure 
of the proposed Otto-cycle engine-based ABT program. These engine 
credits could be used by manufacturers to facilitate meeting the 
proposed engine standard. However, EPA is concerned that significant 
quantities of engine-based credits could flow to the chassis-based 
program, thus potentially having the effect of significantly postponing 
the introduction of vehicles with emission levels below the proposed 
vehicle standards. EPA would likely want to structure provisions for 
exchanging credits such that the exchanges would be limited for use in 
averaging and trading within a given model year, but banked credits 
could not be exchanged. EPA requests comment on structuring credit 
exchanges in this manner.
    For the 2004 and later model years, the proposal would require 
manufacturers to certify a large portion of their Otto-cycle heavy-duty 
vehicles to the vehicle-based provisions (via chassis testing), thus 
reducing the opportunity to generate Otto-cycle engine-based credits. 
In addition, the proposed engine-based emission standards would be 
significantly more stringent starting with the 2004 model year, thus 
making generation of engine-based credits more difficult. For these 
reasons, exchanging credits earned starting in the 2004 model year 
between the chassis-based and engine-based ABT programs may be a 
desirable option for manufacturers.
    Another issue for credit exchanges in 2004 and later model years is 
that vehicle credits would be based on NOX only emissions 
and the engine credits would be based on NMHC+NOX emissions. 
EPA believes that the NMHC portion of engine emissions compared to 
NOX emissions is about 15 percent of total emissions, or 
between 0.1 and 0.2 g/bhp-hr. EPA requests comment on allowing credit 
exchanges without regard to this difference in the standards, or 
alternatively, requiring the use of an appropriate factor (e.g., the 15 
percent factor noted above) to apply to exchanges of NOX-
only and NMHC+NOX credits.
    To summarize, EPA is not proposing allowing exchanges between the 
two Otto-cycle ABT programs at this time, but will consider finalizing 
provisions that would allow such exchanges if our concerns can be 
addressed. Specifically, EPA requests comments on the following issues:
     Allowing manufacturers to transfer credits between the 
Otto-cycle engine and vehicle ABT programs;
     Restricting the transfers of credits between the two ABT 
programs to credits earned in the 2004 and later model years;
     The derivation of conversion factors that would make 
transfers of credits appropriate, including the test methodology and 
appropriate engine and vehicle parameters used to derive the factors 
(horsepower, vehicle weight, etc.);
     Ensuring that credit exchanges do not effectively delay 
introduction of cleaner vehicles;
     How to address exchanging NMHC credits with 
NMHC+NOX credits and vice versa;
     Limiting the exchange of credits to engines and vehicles 
below 14,000 pounds GVWR because engines rated for vehicles above this 
would not have any

[[Page 58499]]

counterparts certified to chassis-based provisions.
     Limiting the exchanges between the two Otto-cycle ABT 
programs to averaging and trading only.
     What impact the broader exchange program would have on the 
degree of the emission reduction of the standards and the 
appropriateness of such an approach.
4. Evaporative Standards/Onboard Refueling Vapor Recovery
    Consistent with the proposal to move all complete vehicles 8,500 to 
14,000 lbs GVWR from the current engine-based program to a chassis-
based program, EPA is proposing that such vehicles also be certified 
according to the chassis-based enhanced evaporative test procedures. In 
addition, the Agency is proposing to require complete HDVs to meet an 
ORVR standard in a manner similar to that required of heavy light-duty 
trucks. Each of these provisions is discussed in depth in the following 
sections. The Agency is not proposing any changes to the current 
evaporative emission standards or test procedures for the engine-based 
program at this time.
a. Enhanced Evaporative Emissions
    In 1993, EPA adopted enhanced evaporative test procedures for LDVs, 
LDTs and HDVs to be phased in beginning with the 1996 model year, with 
full compliance required by the 1999 model year (see 55 FR 16002, March 
24, 1993). Under the enhanced evaporative requirements adopted in 1993 
the provisions for LDVs and LDTs are essentially the same as those for 
HDVs with two main differences. The first difference is that the actual 
levels of the emission limits are higher for HDVs due to their 
typically larger fuel tanks. EPA is not proposing any changes to the 
HDV numerical evaporative limits in this proposed rule. The second 
difference is in the driving cycles used in the test sequence, as 
described in the next paragraph.
    The urban dynamometer driving schedule (UDDS) used for HDVs is 
somewhat shorter than that used for light-duty, both in terms of 
mileage covered and minutes. What this means in practical terms is 
that, while the light-duty and heavy-duty procedures generally parallel 
each other, under the heavy-duty procedure there is considerably less 
driving time than under the light-duty procedure. This results in 
considerably less time for canister purge under the heavy-duty 
procedure than under the light-duty procedure.
    EPA recognizes this discrepancy between its light-duty and heavy-
duty programs, and has routinely provided waivers under the enhanced 
evaporative program which allow the use of the light-duty procedures 
for heavy-duty certification testing. The Agency does not believe that 
this approach impacts the stringency of the standards. Further, it is 
consistent with CARB's treatment of medium-duty vehicles. EPA is 
proposing that this approach be formally adopted for all complete 
vehicles which are certified according to the provisions of the 
chassis-based program discussed elsewhere in this notice. The Agency 
requests comment on this approach to evaporative emissions testing for 
complete HDVs, and also requests comment on whether it should be 
extended to those HDVs which will remain in the engine-based program.
b. Onboard Refueling Vapor Recovery
    Onboard refueling vapor recovery systems prevent the fuel vapors 
which are displaced from a vehicle's fuel tank during refueling from 
entering the atmosphere. Typically, the displaced fuel vapors are 
routed to a charcoal canister where they are subsequently routed to the 
engine to be burned as fuel. EPA adopted ORVR requirements applicable 
to light-duty vehicles and light-duty trucks (see 59 FR 16262, April 6, 
1994). These requirements are being phased in beginning with the 1998 
model year for LDVs, the 2001 model year for light LDTs (6,000 lb and 
under GVWR), and 2004 for heavy LDTs (6,001 through 8,500 lb GVWR).
    During the original ORVR rulemaking, EPA chose not to apply ORVR to 
HDVs for several reasons. First, a sizeable percentage of HDVs are sold 
as incomplete vehicles. In such cases EPA is concerned that secondary 
manufacturers may improperly modify or incorrectly complete the vehicle 
fuel system (which is usually not fully installed for incomplete 
vehicles). In such cases the primary manufacturer may have legal 
liability for potential problems. Second, the application of ORVR to 
HDVs could be more difficult than to LDVs and LDTs. This is because HDV 
fuel systems are sometimes configured differently than their LDV/LDT 
counterparts. This is especially true of the larger HDVs which tend to 
have large fuel tanks with short or almost nonexistent fillnecks. 
Finally, under the current HDV regulatory scheme, the engine would be 
certified separately from the ORVR system. This would result in 
additional challenges in matching the canister purge provided by the 
engine with the needs of each ORVR system.
    EPA still believes that the above mentioned concerns are valid for 
some HDVs. However, the Agency also believes that, in light of the 
proposal to move to a chassis-based compliance program for complete 
vehicles, they are only valid for the larger, incomplete vehicles. The 
majority of HDVs are simply heavy-duty configurations of LDTs, with 
fuel systems similar to or the same as their light-duty counterparts. 
With this in mind EPA is proposing to require ORVR controls on all 
complete HDVs up to 10,000 GVWR in the same manner and on the same 
schedule as heavy LDTs. Thus, complete HDVs will be required to meet a 
refueling emission standard of 0.20 grams per gallon of fuel dispensed. 
For purposes of ORVR applicability, EPA is proposing that complete 
vehicle means a vehicle that leaves the primary manufacturer's control 
with its primary load carrying device or container attached.
    The proposed ORVR standard would be phased in with 40 percent 
compliance required in the 2004 model year, 80 percent compliance in 
the 2005 model year, and 100 percent compliance in the 2006 model year. 
This phase-in is the same as that currently in place for heavy LDTs. 
EPA believes that using the same phase in schedule for heavy LDTs and 
HDVs will allow for a lower cost and easier phase in, since many HDVs 
are simply heavy duty versions of light duty configurations. Further, 
EPA is proposing that heavy LDTs and HDVs be considered a single 
category for the purposes of the phase in. In other words, the percent 
compliance requirements for a given model year would apply to heavy 
LDTs and HDVs as a single group, rather than to each group separately. 
EPA recognizes that combining these two categories into one may have 
the effect of modifying the stringency of the existing LDT 
requirements. However, EPA believes that this is appropriate because it 
will allow for additional flexibility in the implementation of ORVR 
systems that may be the same for heavy LDTs and HDVs. Also, given the 
proposed phase-in requirements, if less than the required percentage of 
heavy LDTs are certified to the ORVR requirement, it follows that 
greater than the required percentage of the heavy-duty vehicles would 
have to be certified to the ORVR requirements.
    As was previously mentioned, EPA is proposing to phase in ORVR to 
HDVs in the same way as it is being phased in for heavy LDTs. This is 
because most covered HDVs are simply heavy-duty versions of light-duty 
configurations,

[[Page 58500]]

and the ORVR systems developed for the light-duty configurations can be 
readily applied to their heavy-duty counterparts. However, EPA is aware 
that not all covered HDVs have light-duty counterparts. Given the 
number of other emission requirements taking effect in 2004, EPA 
believes that the manufacturers' development resources may be spread 
thin prior to 2004, making development of ORVR systems for HDVs which 
do not have a light-duty counterpart excessively burdensome in that 
time frame. Thus, EPA is considering alternative timing options for the 
application of ORVR to HDVs that do not have light-duty counterparts. 
One alternative is to simply require ORVR on these vehicles (those that 
do not have light-duty counterparts) in 2006, with no phase in prior to 
2006. EPA requests comment on this option, as well as other 
alternatives. EPA also requests comment on how to best define which 
HDVs do not have light-duty counterparts for the purposes of 
determining which vehicles may be subject to the alternative 
implementation date. Finally, EPA requests comment on whether such a 
delay of ORVR for HDVs without light-duty counterparts is appropriate 
or needed.
    EPA is proposing to limit the application of ORVR to HDVs of 10,000 
lb GVWR and under because the vast majority of HDVs which have light-
duty counterparts fall into this category. For the most part 
application to HDVs of 10,000 lbs GVWR and under should not present any 
new technological challenges. The technology applied for light-duty 
configurations should be readily transferrable to their heavy-duty 
counterparts. The Agency does not believe that limiting the ORVR 
provisions to vehicles 10,000 lbs and under results in any significant 
compromise in environmental benefits since almost all HD Otto-cycle 
complete vehicle sales are of vehicles 10,000 lb or less GVWR.
    Currently, in the review of certification applications for ORVR-
equipped LDVs and LDTs, EPA studies the design of the vehicle's ORVR 
system, its on-vehicle configuration and operation, and consults 
directly with the National Highway Traffic Safety Administration on 
these applications. EPA expects to extend this practice of consulting 
with NHTSA in the review of certification applications for ORVR-
equipped HDVs as well.
    EPA requests comment on all aspects of today's ORVR proposal. 
Specifically, the Agency requests comment on whether the proposed 
definition of complete vehicle for ORVR purposes adequately covers 
those vehicles for which ORVR application will present no substantial 
new challenges, while exempting those vehicles for which concerns 
expressed by EPA in the original ORVR rulemaking remain valid.
5. Compliance Assurance Program
    On July 23, 1998, EPA proposed a new compliance assurance program 
for light-duty vehicles and light-duty trucks known as ``CAP 2000'' 
(see 63 FR 36954, July 23, 1998). The light-duty CAP 2000 program final 
rule was published on May 4, 1999 (see 64 FR 23906, May 4, 1999), with 
only minor changes from the proposed program. In brief, as compared 
with EPA's traditional chassis-based compliance program, CAP 2000 is 
designed to redirect manufacturer and Agency efforts towards in-use 
compliance and give manufacturers more control of certification timing, 
and yet maintain the integrity of the compliance assurance program. 
Aspects of the CAP 2000 program include streamlined certification, 
manufacturer in-use testing.
    In today's action, EPA proposes that the CAP 2000 program would be 
the compliance assurance program for heavy-duty vehicles certified to 
chassis-based standards (hereafter referred to as ``chassis-based 
HDVs'').69 EPA has proposed modifications to Part 86, 
Subpart S, that would extend the applicability of CAP 2000 to chassis-
based HDVs. Key aspects of the proposed CAP 2000 program as it would 
apply to chassis-based HDVs are described below, followed by a 
discussion of issues and possible modifications to the light-duty CAP 
2000 program considered by the Agency in the development of the 
proposal to extend the CAP 2000 program to chassis-based HDVs.
---------------------------------------------------------------------------

    \69\ The compliance assurance program for heavy-duty engines 
subject to engine-based standards is discussed in section II.C.2 of 
this preamble.
---------------------------------------------------------------------------

    EPA believes that it is appropriate to extend the CAP 2000 program 
to chassis-based HDVs for the following reasons. First, CAP 2000 for 
HDVs would provide pre-production certification flexibilities, while 
providing an emphasis on checking real in-use emissions, as compared 
with the traditional light-duty chassis-based compliance program. As 
with light-duty vehicles, EPA believes that it is appropriate to 
improve pre-production compliance procedures, to reduce the 
manufacturer's certification burden, and to shift the focus of 
compliance assessment towards in-use testing, which is expected to 
generate significant amounts of in-use data that are currently not 
available. Second, applying CAP 2000 to chassis-based HDVs would align 
EPA's chassis-based compliance programs for light-duty vehicles, light-
duty trucks, and heavy-duty vehicles. Third, EPA's proposal to extend 
CAP 2000 to chassis-based HDVs would further harmonize the EPA and ARB 
programs for this industry. The California Air Resources Board is 
adopting the CAP 2000 program for chassis-certified medium-duty 
vehicles in the 8,500 to 10,000 gross vehicle weight range, beginning 
in the 2001 model year.
a. CAP 2000 for HDVs
    For the certification process, manufacturers would divide their 
product lines into new units called ``durability groups'', determined 
according to common emission deterioration elements. A vehicle with the 
``worst case'' durability would be chosen from the durability group to 
establish the rate of emission deterioration expected from that group. 
The procedures used to determine durability would be developed by the 
manufacturer, with EPA approval. Durability groups would then be 
subdivided into ``test groups'', and a vehicle representative of each 
test group would be tested to show emission compliance. Once compliance 
has been demonstrated, certification could proceed. The CAP 2000 
program provisions for information collection are streamlined from the 
traditional light-duty chassis-based compliance regulations. The timing 
of information submittal has been optimized to provide some flexibility 
for manufacturers, and the amount of information has been reduced, 
without compromising the Agency's information needs for future 
compliance or enforcement issues.
    A second element of the proposed chassis-based HDV CAP 2000 
 requirements is manufacturer in-use testing. There are two 
parts to the program. Part one requires manufacturers to perform in-use 
emission testing on privately owned vehicles in an ``as-received'' 
state. This ``in-use verification testing'' would occur on low mileage 
and high mileage test fleets. The size of the low and high mileage 
fleets would be dictated by sales categories. Small volume 
manufacturers and small volume test groups would have little or no 
testing, depending on sales limits. In-use verification testing data 
would be used by the manufacturer to improve the predictive quality of 
its durability program, and by the Agency to target vehicle testing for 
a recall program. Part

[[Page 58501]]

two requires manufacturers to conduct additional testing of a test 
group when the in-use verification program data for the test group 
equals or exceeds a mean of 1.3 times the standard, with a 50 percent 
or greater failure rate for the test group sample at either the low or 
high mileage test point. The second level of in-use testing, known as 
``in-use confirmatory testing'', would be performed on ``properly 
maintained and used'' vehicles and could be used to determine the need 
for recall. The preambles of the July 23, 1998, CAP 2000 proposed rule 
and the May 4, 1999, CAP 2000 final rule provide further discussion of 
these and other aspects of the CAP 2000 program.
b. Proposed Modifications to the CAP 2000 Program for Chassis-Based 
HDVs
    In the development of the CAP 2000 proposal for chassis-based HDVs, 
EPA considered several issues and possible modifications to the light-
duty vehicle CAP 2000 program. These issues are discussed below.
    First, EPA proposes that the ``heavy-as-light'' provision in the 
current regulations (see 40 CFR 86.001-01(b) and 40 CFR 86.1801(c)(1)) 
would be available through the 2003 model year; starting with the 2004 
model year, the ``heavy-as-light'' provision would no longer be 
available. EPA's ``heavy-as-light'' provision permits a manufacturer to 
certify a HDV of 14,000 pounds GVWR or less in accordance with the 
light-duty truck provisions. In effect, this provision allows 
manufacturers to certify these HDVs on a chassis dynamometer rather 
than on an engine dynamometer, as long as the HDVs comply with the more 
stringent light-duty truck standards. Today's action obviates the 
``heavy-as-light'' provision after the 2003 model year. EPA is also 
proposing new provisions that would allow manufacturers flexibilities 
in grouping vehicles into test groups, as well as provisions allowing 
manufacturers to certify incomplete HDVs under the chassis-based HDV 
program.
    Second, manufacturers have requested the ability to group vehicles 
from different test weight categories into the same test group for 
compliance purposes. For example, manufacturers would like the 
flexibility to group HDVs with LDT3s or LDT4s, or to group HDVs above 
and below 10,000 pounds GVWR together, for compliance purposes. In the 
light-duty CAP 2000 program, vehicles must be subject to the same 
emission standards to be grouped into the same test group (see 40 CFR 
86.1827(a)(5)). However, EPA believes it is reasonable to allow 
manufacturers to voluntarily certify to more stringent standards. EPA 
is today proposing to allow manufacturers to request that vehicles from 
different weight categories be grouped together in the same test group, 
as long as the vehicles are then subject to the most stringent 
standards that would be applicable to any vehicles within that 
grouping. Voluntary certification to the more stringent emission 
standards means that the manufacturer would be subject to enforcement 
against the more stringent standards. EPA requests comment on the 
proposal to remove the ``heavy-as-light'' provision after the 2003 
model year, the proposal to allow manufacturers to request to certify 
incomplete HDVs under the chassis-based HDV program, and the proposal 
that manufacturers be allowed to request that vehicles from different 
weight categories, which might be subject to different standards, be 
grouped together in one test group meeting the most stringent set of 
standards.
    Third, in discussions about the application of CAP 2000 to chassis-
based HDVs, manufacturers have questioned whether the light-duty 
``AMA'' cycle would be allowed for durability testing.70 In 
response, EPA is proposing that the AMA cycle would not be available as 
a durability procedure for chassis-based HDVs. (The CAP 2000 program 
likewise disallows the AMA durability procedure, but does allow for the 
carryover of AMA-based deterioration factors.) This proposal differs 
from the light-duty CAP 2000 program, in which under certain conditions 
the AMA cycle would be accepted during a transition period of three 
years, until the 2004 model year.71 This transition period 
is reasonable for the light-duty CAP 2000 program, given that the 
light-duty compliance program had traditionally rested on use of the 
AMA cycle for durability demonstrations, and also that the use of the 
AMA cycle data is limited to the use of existing data generated for a 
2000 model year or earlier certification (CAP 2000 requires that all 
new exhaust durability data be generated according to a manufacturer 
durability procedure approved by EPA). Manufacturers have long 
identified the AMA durability process as very costly and requiring 
extensive lead time for completion. EPA has been concerned about the 
ability of any fixed cycle, including the AMA cycle, to accurately 
predict in-use deterioration for all vehicles. In fact, EPA has 
particular concerns that the AMA does not represent the driving 
patterns of today and does not appropriately age current design 
vehicles. As a result, EPA believes that the AMA may have become 
outdated.72
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    \70\ See Item # IV-E-24 in EPA Air Docket #A-95-27. The ``AMA 
cycle'' is a part of EPA's standard light-duty durability process 
prior to CAP 2000, which requires manufacturers to accumulate 
mileage on a pre-production vehicle over a prescribed mileage 
accumulation driving cycle, specified in 40 CFR Part 86 (commonly 
referred to as the ``AMA cycle''), for 100,000 miles to simulate 
deterioration over the useful life of the vehicle.
    \71\ This is limited to only those products which qualify for 
carryover. New engine designs may not use the AMA carryover option.
    \72\ See the CAP 2000 NPRM (63 FR 39659, July 23, 1998) and 
Final Rule (64 FR 23913).
---------------------------------------------------------------------------

    Based on these concerns and also the fact that today's proposal 
includes provisions for averaging, banking and trading credits across 
test groups (in which FELs would be set based on durability procedures 
that would need to be comparable across test groups), EPA is proposing 
that the AMA cycle would not be automatically available as a durability 
procedure for chassis-based HDVs, unless a manufacturer were able to 
obtain approval for it. As in the light-duty CAP 2000 program, to 
obtain approval for a durability process, EPA is proposing to require 
that manufacturers provide data showing that the aging procedures would 
predict the deterioration of the significant majority of in-use 
vehicles over the breadth of their product line which would ultimately 
be covered by this procedure. This demonstration would be more than 
simply matching the average in-use deterioration; manufacturers would 
need to demonstrate to EPA's satisfaction that their durability 
processes would result in the same or more deterioration than is 
reflected by the in-use data for a significant majority of their 
vehicles. This approval process is the same as that already established 
for EPA's first phase of the light-duty revised durability program 
(RDP-I).73 EPA requests comment on the proposal to not 
automatically allow the use of the AMA cycle for chassis-based HDVs.
---------------------------------------------------------------------------

    \73\ In RDP-I manufacturers have typically shown that their 
durability programs cover ninety percent or higher of the 
distribution of deterioration rates experienced by vehicles in 
actual use. See EPA's guidance letter CD-94-13 dated July 29, 1994, 
available for review in the public docket.
---------------------------------------------------------------------------

    Fourth, manufacturers have expressed several concerns about in-use 
testing for chassis-based HDVs, including potential difficulties in 
procuring vehicles for testing given the commercial use of many of 
these vehicles, and the appropriateness of in-use confirmatory testing 
for HDVs.74 EPA believes that the provisions of the light-
duty CAP 2000 program, when extended to chassis-

[[Page 58502]]

based HDVs, are sufficient to address manufacturer concerns about 
possible difficulties in procuring vehicles for in-use testing. If a 
manufacturer or a manufacturer's test group qualifies for in-use 
testing under a small volume sampling plan, there may be no in-use 
testing requirements (for volumes up to 5000), or as few as two tests 
per test group (for volumes up to 15,000); also, vehicles for testing 
may be owned by or under the control of the manufacturer (as opposed to 
being procured form customers) (see 40 CFR 86.1838-01(c)). In addition, 
if any manufacturer believes it is unable to procure the test vehicles 
necessary to test the required number of vehicles in a test group, the 
manufacturer may request a smaller sample size for any test group, 
subject to advance EPA approval (see 40 CFR 86.1845-01(c)(3)). EPA 
requests comment on the proposed provisions of the HDV CAP 2000 program 
regarding procuring vehicles for in-use testing.
---------------------------------------------------------------------------

    \74\ See Item #IV-E-24 in EPA Air Docket #A-95-27.
---------------------------------------------------------------------------

    Manufacturers have also suggested that it would be desirable to 
have a transition to the in-use confirmatory testing requirements over 
a period of years, as was available in the light-duty vehicle CAP 2000 
program, rather than requiring this testing in the same year that the 
chassis-based certification and in-use verification testing 
requirements go into effect.75 EPA is proposing that in-use 
confirmatory testing would be required for chassis-based HDVs. However, 
EPA believes that a delay in the in-use confirmatory testing 
requirements is appropriate in order to allow manufacturers to gain 
experience with chassis-based certification and in-use verification 
testing for chassis-based HDVs. Thus, EPA is proposing that the in-use 
confirmatory requirements would be applicable to vehicles produced 
starting with the 2007 model year. While manufacturers would not be 
required to conduct in-use confirmatory testing for vehicles produced 
prior to the 2007 model year, EPA would be fully prepared to 
investigate any high emissions indicated through manufacturer in-use 
verification testing or any other means. EPA requests comment on this 
proposal to require in-use confirmatory testing starting with the 2007 
model year.
---------------------------------------------------------------------------

    \75\ See Item # IV-E-24 in EPA Air Docket #A-95-27. On the 
light-duty side, some manufacturers had experience with in-use 
testing through the RDP-I in-use verification testing, starting as 
early as the 1994 model year.
---------------------------------------------------------------------------

    Finally, certain aspects of the light-duty CAP 2000 program, as 
contained in 40 CFR part 86, subpart S, would not apply to chassis-
based HDVs, since EPA is not proposing requirements for HDVs in these 
areas at this time. These areas include provisions relating to 
intermediate useful lives, certification short test, cold temperature 
CO requirements, fuel economy programs, and supplemental FTP 
requirements.
    In summary, EPA is proposing to extend the light-duty CAP 2000 
program to chassis-based HDVs, with the following minor modifications. 
First, the option to certify HDVs under ``heavy-as-light'' provisions 
would no longer be available after the 2003 model year; instead, 
manufacturers could request to certify incomplete HDVs under the 
chassis-based HDV program. Second, manufacturers could request to group 
vehicles from different weight categories or subject to different 
standards into the same test group, provided that they meet the most 
stringent standards applicable to vehicles within that test group. 
Third, the AMA cycle would not automatically be available for HDVs as a 
durability procedure. Fourth, the in-use confirmatory testing 
requirement would be delayed for HDVs until the 2007 model year. Fifth, 
certain elements of the CAP 2000 program would not apply to chassis-
based HDVs.
    EPA requests comment on all aspects of this proposal for a chassis-
based HDV compliance assurance program.
6. Useful Life
    Currently, the useful life mileage interval for Otto-cycle HD 
engines is 8 years or 110,000 miles, whichever occurs first. The useful 
life for these vehicles in the California MDV program is 120,000 miles, 
which is also the useful life of heavy light-duty trucks. EPA proposes 
to adopt the useful life mileage interval of 120,000 miles for the HD 
Otto-cycle vehicles program. This approach allows consistency across 
the programs and is consistent with the use of the vehicles.
7. Aftermarket Alternative Fuels Conversions
    There are companies that convert heavy-duty engines originally 
designed to run on conventional fuel to run on an alternative fuel. 
These engines are subject to EPA standards and the conversion 
manufacturers certify the converted engines. It is possible that some 
of these vehicles could be considered incomplete by the original 
manufacturer and certified to engine-based standards. However, when 
they reach the aftermarket conversion manufacturer, they may have the 
cargo carrying container attached and could be considered complete 
vehicles. In discussions with the conversion manufacturers they 
expressed a general preference for vehicle-based testing due to the 
greater availability of test facilities and lower costs. However, the 
conversion manufacturers raised concerns that it may be infeasible or 
unreasonable for them to test very large vehicles, those well over 
10,000 pounds GVWR, on a chassis dynamometer due to lack of available 
test facilities designed to handle these very large vehicles.
    EPA proposes the following two provisions for vehicles over 10,000 
pounds GVWR. EPA proposes that aftermarket conversion manufacturers can 
choose to test vehicles that are originally designed and considered by 
the original manufacturer to be incomplete vehicles to either the 
engine or vehicle-based standards. In addition, aftermarket conversion 
manufacturers may certify complete vehicles to the engine-based 
standards due to the lack of available test facilities upon pre-
approval from EPA. EPA requests comments on these proposed provisions.

F. Proposal To Revise the Definition of Light-Duty Truck

1. Background
    In May of 1999, EPA proposed stringent new Tier 2 standards for 
passenger cars and light-duty trucks beginning in the 2004 model year 
(64 FR 26004, May 13, 1999). We are now in the process of analyzing the 
many public comments we received on the Tier 2 proposal. The proposed 
Tier 2 program would require all passenger cars and light-duty trucks 
to meet the same Tier 2 exhaust emissions standards by model year 2009. 
The phase-in of the standards would begin in 2004 with passenger cars 
and lighter light-duty trucks and end in 2009 when all light-duty 
trucks would be required to meet the standards. We proposed the same 
emissions standards for both cars and light-duty trucks because of the 
increased use of light-duty trucks primarily for personal 
transportation. The Tier 2 proposal did not contain any specific 
regulatory proposals for heavy-duty vehicles. We did, however, request 
comment on several options discussed in the proposal to prevent 
manufacturers from redesigning LDT4s so that they would fall into the 
heavy-duty vehicle category in order to avoid Tier 2 
standards.76
---------------------------------------------------------------------------

    \76\ The LDT4 category contains the largest of the LDTs. The 
category includes LDTs with a gross vehicle weight greater than 
6,000 pounds and an adjusted loaded vehicle weight of greater than 
5,750 pounds.
---------------------------------------------------------------------------

    We received several comments strongly supporting including all 
passenger vehicles in the Tier 2

[[Page 58503]]

program, regardless of vehicle weight. These commenters were very 
concerned that the Tier 2 standards would not apply to any vehicles 
above 8,500 pounds GVWR. Commenters believe that a number of these 
vehicles categorized by EPA as heavy-duty are primarily used as 
personal transportation much like their light-duty counterparts. Many 
commenters cited the new Ford Excursion sport-utility vehicle (SUV) as 
an example of a vehicle designed primarily for passenger transportation 
that would currently be classified as heavy-duty. Commenters also 
expressed concern that a significant difference in the standards for 
light-duty trucks and heavy-duty vehicles would encourage manufacturers 
to redesign vehicles to make them fit the definition of heavy-duty 
vehicles.
    EPA also received comment stating that no heavy-duty vehicles 
should be included in the Tier 2 program. The Alliance of Automobile 
Manufacturers commented that full product line manufacturers currently 
offer light-duty and heavy-duty versions of vehicles such as pickups 
and vans and would not want to create a product void in the LDT4 market 
segment. They further commented that manufacturers would refrain from 
changing their vehicles in ways that would increase cost and decrease 
performance and marketability. Commenters also noted that heavy-duty 
vehicles are designed for a broad range of purposes. They are designed 
to be heavier, stronger, and more durable and it would be impossible 
for such vehicles to meet light-duty emissions standards, claimed some 
commenters.
    After carefully considering all of the comments, we believe both 
general perspectives have merit depending on the type of vehicle being 
considered. A small minority of sales in the complete heavy-duty 
vehicle category consist of vehicles that are more clearly designed for 
personal use, such as SUVs and passenger vans. All of these vehicles 
are below 10,000 pounds GVWR. In addition, we are concerned that there 
will be an increase in new vehicle offerings marketed primarily for 
passenger transportation in this market segment in the future. As 
personal use passenger vehicles, they would be more likely to be used 
as personal transportation and operated under lightly loaded conditions 
more of the time. We propose that these passenger vehicles (both 
gasoline and diesel fueled) be included in the Tier 2 program, tested 
as light-duty trucks, and held to Tier 2 standards. The following 
sections provide our detailed proposal to capture these vehicles in the 
Tier 2 framework and provides an overview of the Tier 2 emissions 
standards that would apply.
    For the remaining vehicles in the heavy-duty category (primarily 
traditional large pickup trucks, cargo vans, and incomplete vehicles), 
we continue to believe the heavy-duty standards and test procedures 
proposed in this rulemaking are most appropriate. Heavy-duty vehicles 
would be tested under more heavily loaded conditions compared with 
light-duty trucks in Tier 2. Considering this difference in test 
conditions, we believe that the heavy-duty vehicle standards we are 
proposing in this rule for 2004 would be similar in stringency to the 
Tier 2 standards that have been proposed for light-duty trucks in this 
time frame.
    In addition, we are considering the need for more stringent heavy-
duty vehicle standards for 2007 and later model years, as discussed in 
section X.C of this preamble.
2. Proposal
    As noted above, we believe it is appropriate to consider including 
certain vehicles currently classified as heavy-duty vehicles in the 
proposed light-duty Tier 2 program. In order to accomplish this 
objective, the proposed regulations include a revised definition of 
``light-duty truck'' designed to bring large models of SUVs and 
passenger vans into the proposed Tier 2 program. The proposed 
regulations also contain a parallel revision to the definition of 
``heavy-duty vehicle'' in order to prevent an overlap in the vehicles 
covered by the two definitions.
    Specifically, the proposed definition of light-duty trucks seeks to 
include the targeted vehicles by stating that a light-duty truck, in 
addition to those vehicles that meet the current definition, is also 
any complete vehicle between 8,500 and 10,000 pounds GVWR that is 
designed primarily for personal transportation and has a capacity of up 
to 12 persons. We expect that the proposed definition would exclude 
vehicles that have been designed for a legitimate work function as 
their primary use, such as the largest pick-up truck, the largest 
passenger vans, and cargo vans; these vehicles would continue to be 
categorized as heavy-duty and would be subject to applicable heavy-duty 
standards. However, we request comment on whether the proposed 
definition adequately excludes these vehicles, or whether additional 
criteria may be needed. If additional criteria are believed to be 
needed, we request comment on how such criteria might be used (i.e., 
what are appropriate cut points). For example, the definition could 
include the use of factors such as whether the vehicle's body is fully 
or almost fully enclosed (i.e., there is no significant exterior cargo 
space such as there is on a pick-up truck), the portion of the total 
payload that might be consumed by vehicle passengers, the portion of 
available chassis space consumed by passenger seating, the percent of 
the total GVWR comprised of the vehicle's curb weight, or other 
relevant factors. We believe that this definition will capture SUVs, 
such as the Chevrolet Suburban and the Ford Excursion, and bring them 
into the proposed Tier 2 program. Table 5 identifies the currently 
produced vehicles that we believe would be subject to the Tier 2 
program according to the revised definition of light-duty truck.

    Table 5.--Passenger Vehicles Between 8,500 and 10,000 Pounds GVWR
------------------------------------------------------------------------
           Vehicle               Vehicle type          Manufacturer
------------------------------------------------------------------------
Suburban.....................  SUV.............  GM.
Excursion....................  SUV.............  Ford.
Express Wagon (G2500 and       Passenger van...  GM.
 G3500).
Dodge Ram Wagon 3500.........  Passenger van...  Daimler Chrysler.
Econoline Super-duty Wagon     Passenger van...  Ford.
 (E250 and E350).
------------------------------------------------------------------------

    Vehicles meeting the proposed additional element to the light-duty 
truck definition would be classified as heavy light-duty trucks (HLDTs) 
according to definitions that already exist in the regulations, and 
therefore would be subject to the standards in EPA's proposed Tier 2 
program.77 The

[[Page 58504]]

specifics of how these vehicles would be folded into the Tier 2 program 
are described below.
---------------------------------------------------------------------------

    \77\ LDT3 and LDT4s are considered heavy light-duty trucks 
(HLDTs).
---------------------------------------------------------------------------

3. Integration Into Proposed Tier 2 Program
a. Tier 2 Standards for New HLDTs
    We propose that for 8,500-10,000 pound GVWR vehicles covered under 
the revised definition of light-duty trucks discussed above, these 
vehicles would meet the same standards as the LDT3 and LDT4 vehicles in 
Tier 2, that is, this new category of vehicles would be part of the 
Tier 2 heavy-light duty truck program. That program is discussed in 
detail in the Tier 2 proposal, and will only be summarized here. The 
reader should review the entire Tier 2 proposal to gain a full 
understanding of the Tier 2 program for HLDTs. The new HLDTs covered by 
the proposed change in definition would be averaged in with a 
manufacturers' LDT3s and LDT4s so that 50 percent of the HLDTs would 
meet Tier 2 standards in 2008, and 100 percent would have to meet Tier 
2 standards in 2009. As Tier 2 vehicles, these large SUVs and passenger 
vans would be included with other HLDTs in meeting the 0.07 g/mi 
average NOX standard in 2008. In 2009, they would be 
included with all Tier 2 LDVs and LDTs in meeting the 0.07 g/mi 
NOX average standard (see Table 6).

BILLING CODE 6560-50-P

[[Page 58505]]

Table 6.--Tier 2 and Interim Non-Tier 2 Phase-in and Exhaust 
Averaging Sets (Bold lines around shaded areas indicate averaging 
sets)
[GRAPHIC] [TIFF OMITTED] TP29OC99.002


BILLING CODE 6560-50-C

    a 0.60 NOX cap applies to balance of 
vehicles during the 2004-2006 phase-in years.
    b Alternative phase-in provisions permit 
manufacturers to deviate from the 25/50/75% 2004-2006 and 50% 2008 
phase-in requirements and provide credit for phasing in some 
vehicles during one or more of these model years.
    c HLDT vehicles between 8,500 and 10,000 pound GVWR 
will be meeting the 1998 Heavy-duty standards during this time 
frame.

    As described in the Tier 2 proposal, manufacturers would meet the 
Tier 2 NOX standard by certifying to one of seven emission 
bins, and using averaging to meet the corporate average NOX 
standard of 0.07 g/mi. The proposed Tier 2 exhaust emission standards 
for all bins are shown in Table 7 and Table 8.

             Table 7.--Tier 2 Light-Duty Full Useful Life (120,000 mile) Exhaust Emission Standards
                                                [Grams per mile]
----------------------------------------------------------------------------------------------------------------
             Bin No.                    NOX            NMOG             CO             HCHO             PM
----------------------------------------------------------------------------------------------------------------
7...............................            0.20           0.125             4.2           0.018            0.02
6...............................            0.15           0.090             4.2           0.018            0.02
5...............................            0.07           0.090             4.2           0.018            0.01
4...............................            0.07           0.055             2.1           0.011            0.01
3...............................            0.04           0.070             2.1           0.011            0.01
2...............................            0.02           0.010             2.1           0.004            0.01
1...............................            0.00           0.000             0.0           0.000            0.00
----------------------------------------------------------------------------------------------------------------


          Table 8.--Tier 2 Light-Duty Intermediate Useful Life (50,000 mile) Exhaust Emission Standards
                                                [Grams per mile]
----------------------------------------------------------------------------------------------------------------
             Bin No.                    NOX            NMOG             CO             HCHO             PM
----------------------------------------------------------------------------------------------------------------
7...............................            0.14           0.100             3.4           0.015  ..............
6...............................            0.11           0.075             3.4           0.015  ..............
5...............................            0.05           0.075             3.4           0.015  ..............
4...............................            0.05           0.040             1.7           0.008  ..............
----------------------------------------------------------------------------------------------------------------


[[Page 58506]]

b. Interim Standards for New HLDTs
    Between 2004 and 2007, these new HLDT vehicles would have two 
options; to participate in early banking for the Tier 2 program, or be 
part of the Tier 2 HLDT Interim program along with LDT3 and LDT4 
vehicles. The early banking option is described in detail for HLDT in 
the Tier 2 proposal.
    The Interim program proposed in Tier 2 phases in between 2004 and 
2007 (see Table 6). Our interim standards for HLDTs would begin in 
2004. The Interim Program for HLDTs would set a corporate average 
NOX standard of 0.20 g/mi that would be phased in between 
2004 and 2007. The interim HLDT standards, like those for Tier 2 LDV/
LLDTs would be built around a set of bins (see Tables 9 and 10). As 
shown in Table 6, the phase-in would be 25 percent in the 2004 model 
year, 50 percent in 2005, 75 percent in 2006, and 100 percent in 2007. 
The program would remain in effect through 2008 to cover those HLDTs 
not yet phased into the Tier 2 standards (a maximum of 50%). Vehicles 
not subject to the interim corporate average NOX standard 
during the 2004-2006 phase-in years would be subject to the least 
stringent bin (Bin 5) so their NOX emissions would be 
effectively capped at 0.60 lg/mi. These vehicles would be excluded from 
the calculation to determine compliance with the interim 0.20 g/mi 
average NOX standard.

             Table 9.--Full Useful Life (120,000 mile) Interim Exhaust Emission Standards for HLDTs
                                                [Grams per mile]
----------------------------------------------------------------------------------------------------------------
             Bin No.                    NOX            NMOG             CO             HCHO             PM
----------------------------------------------------------------------------------------------------------------
5...............................            0.60           0.230            4.2            0.018            0.06
4...............................            0.30           0.180            4.2            0.018            0.06
3...............................            0.20           0.156            4.2            0.018            0.02
2...............................            0.07           0.090            4.2            0.018            0.01
1...............................            0.0             0.00            0.0            0.000            0.0
----------------------------------------------------------------------------------------------------------------


         Table 10.--Intermediate Useful Life (50,000 mile) Interim Exhaust Emission Standards for HLDTs
                                                [Grams per mile]
----------------------------------------------------------------------------------------------------------------
                    Bin No.                          NOX          NMOG          CO          HCHO          PM
----------------------------------------------------------------------------------------------------------------
5..............................................         0.40        0.160          3.4        0.015  ...........
4..............................................         0.20        0.140          3.4        0.015  ...........
3..............................................         0.14        0.125          3.4        0.015  ...........
2..............................................         0.05        0.075          3.4        0.015  ...........
----------------------------------------------------------------------------------------------------------------

    All other aspects of the Tier 2 proposal which covers HLDT vehicles 
would apply to those 8,500-10,000 pound GVWR vehicles classified as 
HLDTs according to the proposed definition described above. The reader 
is encouraged to examine the Tier 2 proposal for a full description of 
these provisions.
c. Technological Feasibility of Tier 2 Standards for New HLDTs
    As discussed above, we believe this new definition of HLDTs between 
8,500 and 10,000 pounds will capture vehicles designed for personal 
transportation purposes, principally sport-utility vehicles and 
passenger vans. Cargo vans and traditional pickups would not be 
classified as HLDTs by this new definition. Table 11 represents our 
estimates of the number of 8,500-10,000 pound GVWR vehicles which would 
be covered by the proposed revision to the light-duty truck definition, 
as well as sales estimates for the LDT3s and LDT4s which currently 
comprise the HLDT category.

    Table 11.--EPA's Estimated 1998 Sales of LDT3, LDT4, and New HLDT
              Vehicles Between 8,500 and 10,000 Pounds GVWR
------------------------------------------------------------------------
                                                              New HLDTs
                                                               between
                                         LDT3 and LDT4        8,500 and
                                                                10,000
                                                              pound GVWR
------------------------------------------------------------------------
Gasoline Vehicle Sales...........  1.5 million.............      <70,000
Diesel Vehicle Sales.............  <1 percent of gasoline         <5,000
                                    LDT3 and LDT4 sales.
------------------------------------------------------------------------

    As can be seen in Table 11, the revision of the LDT definition 
proposed today would increase the total number of HLDT vehicles by less 
than 5 percent. The proposed change in the definition of light-duty 
trucks would result in the diesel fraction being less than 0.5 percent 
of all HLDTs.
    These new HLDT vehicles are similar in engine design to existing 
LDT4 vehicles, and we believe the technological feasibility arguments 
contained in the Tier 2 proposal apply to these vehicles as well. In 
addition to these arguments, Tables 3-9 in the draft RIA for this 
proposal contains a list of 1998 and 1999 model year gasoline vehicles 
certified to the California Medium Duty Vehicle program (using low 
sulfur California fuel). In the 8,500 to 10,000 pound GVWR range, a 
number of engine families have full useful life (120,000 miles) 
NOX emissions in the 0.2 to 0.6 g/mile range, and a few 
families are certified in the 0.1 to 0.3 g/mile NOX range. 
These vehicles are all

[[Page 58507]]

tested at curb weight plus half-payload, while those captured by the 
new definition would be tested at curb weight plus 300 pounds, a less 
stringent test condition. Therefore, a large number of gasoline engine 
families between 8,500 and 10,000 are already capable of meeting the 
highest bin under the Tier 2 Interim program (0.6 g/mile), and a few 
are approaching the Tier 2 NOX standard of 0.07 g/mile, and 
are within the highest NOX bin under Tier 2 (0.2 g/mile 
NOX). In addition, compared to the number of existing LDT3 
and LDT4 vehicles, the number of vehicles captured by the new HLDT 
definition are relatively small (< 5 percent), and the averaging 
program proposed for Tier 2 will provide manufacturers with 
considerable lead time for applying control technology to these 
vehicles.
    As noted above, these new HLDTs are similar in their engine types 
and designs to existing LDT4 vehicles, and because of this we expect 
that these new HLDTs will employ essentially the same types of 
technologies as existing LDT4 vehicles to meet EPA's proposed Tier 2 
standards. Similarly, the costs EPA projected for bringing existing 
LDT4 vehicles into compliance with the Tier 2 standards can also be 
carried over to these new HLDTs. These costs are discussed in detail in 
EPA's proposal for Tier 2 standards, and the reader is urged to refer 
to that discussion for more information (see 64 FR 26070, May 13, 
1999). EPA estimates that bringing these new HLDTs under the Tier 2 
program would cost $270 per vehicle, i.e., the same as for other LDT4s. 
Based on an estimate of approximately 75,000 vehicles affected, annual 
costs would equal about $20 million when the program is fully phased-in 
by 2009. Per vehicle NOX emission reductions of 4.3 g/mi 
would be expected from the current standards. This is a significantly 
larger per vehicle reduction than expected for current LDT4s, so EPA 
anticipates the near term cost effectiveness would be more cost 
effective. We request comment on the application of these cost 
estimates to the vehicles that would be covered by the proposed change 
to the LDT definition. This issue will be analyzed more carefully as 
part of the final rulemaking.
    As outlined above, Tier 2 standards are intended to be ``fuel 
neutral.'' Under the principle of fuel neutrality, all cars and light 
trucks, including those using diesel engines, would be required to meet 
the proposed Tier 2 standards. EPA believes that the proposed program, 
including the phase-in periods, would facilitate the advancement of 
clean diesel engine technologies. EPA further believes that in the long 
term the standards would be within reach for diesel-fueled vehicles in 
combination with appropriate changes to diesel fuel to facilitate 
aftertreatment technologies.
    As discussed in the Tier 2 proposal, the emission reduction 
technology needed to meet these levels for a diesel HLDT would likely 
require advanced diesel aftertreatment devices, such as NOX 
absorbers and PM traps. These technologies have the potential to 
provide emission reductions approaching 90 percent or greater. 
Considering the long lead time available to manufacturers, we believe 
these standards may be feasible for diesel HLDTs, including the 
vehicles that would be captured by the proposed change to the 
definition. In addition, the number of diesel powered vehicles between 
8,500 and 10,000 pounds GVWR which would be classified as HLDTs by the 
proposed new definition is very small, as shown in Table 11. The total 
number of diesel HLDTs (including LDT3 and LDT4) would be less than 0.5 
percent of all HLDTs. Averaging will likely provide the manufacturer 
with additional flexibility to meet both the interim and final Tier 2 
standards.78
---------------------------------------------------------------------------

    \78\ We generally expect that manufacturers would take advantage 
of the flexibilities in the Tier 2 proposal to delay the need for 
diesel vehicles to meet the final Tier 2 levels until late in the 
phase-in period. Because diesel vehicles represent a very small 
percentage of the LDT market, diesel LDTs would not fall under the 
final Tier 2 standards until 2009, giving manufacturers a relatively 
large amount of leadtime. As noted in the Tier 2 proposal, some new 
diesel aftertreatment options may require lower sulfur diesel fuel 
than is currently available. We have issued an Advance Notice of 
Proposed Rulemaking intended to solicit comment on the need for 
reduced sulfur in diesel fuel in order to meet these standards. We 
also believe that the proposed interim standards would be feasible 
for diesels by 2004, with or without the fuel change, given the 
flexibilities associated with those standards.
---------------------------------------------------------------------------

    Considering all of these factors (long lead time, averaging 
program, similarity to LDT3s and LDT4s, and existing certification 
data) , we believe that these new HLDT vehicles will be able to meet 
the Tier 2 interim standards and the Tier 2 final standards. As 
discussed above, the number of these vehicles, compared to the existing 
LDT3 and LDT4 fleet, is relatively small, and averaging will likely 
provide the manufacturer with the needed flexibility to meet both the 
interim and final Tier 2 standards. The conclusion of all of our 
analyses is that the proposed Tier 2 standards for this new category of 
HLDT vehicles would be feasible for gasoline-fueled vehicles operated 
on low-sulfur gasoline. As gasoline-fueled vehicles represent the 
overwhelming majority of the HLDT population (>99.5 percent), including 
those covered by the proposed change in the HLDT definition, EPA 
proposes to find that the proposed standards would be feasible overall 
for HLDT vehicles.
    The Agency is considering adding a bin for HLDTs greater than 8,500 
pounds GVWR for the 2004 thru 2008 model year time frame. This interim 
bin would not be available in 2009 and beyond once the Tier 2 standards 
are fully phased-in. This approach would create an appropriate 
opportunity for flexibility during the phase-in years. We believe that 
appropriate standards for an interim bin for HLDTs above 8,500 pounds 
GVWR are the existing California Medium Duty Vehicle LEV-I standards 
for this category of vehicles (0.9 and 0.12 g/mile for NOX 
and PM, respectively). Under this proposal, these chassis-based 
standards would already be in place for the heavy-duty vehicles between 
8,500 and 10,000 pounds GVWR that would not be classified as HLDTs (see 
section IV.E). In addition, manufacturers would already be meeting 
these standards in California, and could carry over California vehicles 
to the federal program. We request comment on whether such an approach 
should be pursued in the final rule.
    We request comment on all aspects of this proposed change in the 
definition of HLDTs, and the inclusion of these HLDTs in the Tier 2 
program. We specifically seek comments on the appropriateness of the 
10,000 pound GVWR limit as the upper cap for this program and on the 
technological feasibility of the standards being proposed for these 
passenger vehicles. After considering all comments received on this 
proposed change in the definition of HLDTs, it is our intention to 
finalize a change in the definition of LDTs in the Tier 2 final rule, 
if timing permits. If this is deemed infeasible, we would likely 
finalize this provision in the final rule for the heavy-duty 2004 
standards. The Agency requests that any comments on this specific issue 
be sent to the dockets for both this rulemaking and the Tier 2 
rulemaking, A-97-10 (See Section XI for information on how to provide 
written comments on this rule).

G. On-Board Diagnostics

    Today's notice also contains proposed requirements for on-board 
diagnostic systems on heavy-duty vehicles and engines up to 14,000 
pounds GVWR, both Otto-cycle and diesel. The proposed OBD requirements 
are essentially equivalent to those already in place for light-duty 
vehicles and

[[Page 58508]]

trucks,79 including the optional provision that allows 
demonstration of compliance with California OBDII requirements 
80 as a means of satisfying today's federal OBD 
requirements. The Agency is proposing to include OBD requirements in 
today's notice because OBD systems help ensure continued compliance 
with emission standards during in-use operation, and they help 
mechanics to properly diagnose and repair malfunctioning vehicles while 
minimizing the associated time and effort. The codification of OBD 
system requirements would also allow for potential inclusion of heavy-
duty vehicles and engines in inspection/maintenance programs via a 
simple check of the OBD system.
---------------------------------------------------------------------------

    \79\ See 40 CFR 86.099-17; 40 CFR 86.1806-01.
    \80\ See, e.g., Title 13, California Code of Regulations (CCR) 
Sec. 1968.1, as modified pursuant to California Mail Out #97-24 
(December 9, 1997).
---------------------------------------------------------------------------

1. Background on OBD
    Section 202(m) of the CAA, 42 U.S.C. 7521(m), directs EPA to 
promulgate regulations requiring 1994 and later model year LDVs and 
LDTs to contain an OBD system that monitors emission-related components 
for malfunctions or deterioration ``which could cause or result in 
failure of the vehicles to comply with emission standards established'' 
for such vehicles. Section 202(m) also states that EPA may require such 
OBD systems for heavy-duty vehicles and engines.
    On February 19, 1993, EPA published a final rule requiring 
manufacturers of light-duty applications to install such OBD systems on 
their vehicles beginning with the 1994 model year (see 58 FR 9468, 
February 19, 1993). The OBD systems must monitor emission control 
components for any malfunction or deterioration that could cause 
exceedance of certain emission thresholds. The regulation also requires 
that the driver be notified of any need for repair via a dashboard 
light, or malfunction indicator light (MIL), when the diagnostic system 
detects a problem. EPA also allows optional compliance with 
California's second phase OBD requirements, referred to as OBDII (13 
CCR 1968.1), for purposes of satisfying the EPA OBD requirements.
    Since publishing the 1993 OBD final rule, EPA has made several 
revisions to the OBD requirements. On March 23, 1995, EPA published a 
direct final rule that served largely to create more consistency 
between the California OBDII requirements and the EPA OBD requirements 
(see 60 FR 15242, March 23, 1995). The March 1995 rule also put into 
place deficiency provisions for EPA OBD systems that allowed for 
certification despite the presence of minor noncompliances that could 
not be resolved within the time constraints of production schedules. On 
August 30, 1996, EPA published another final rule to allow optional 
compliance with California's newly revised OBDII requirements (61 FR 
45898). On December 22, 1998, EPA published a final rulemaking that 
achieved even further consistency with the California OBDII 
requirements (see 63 FR 70681, December 22, 1998). This recent final 
rulemaking results in essentially identical emission malfunction 
thresholds and identical component monitoring requirements as required 
by the California OBDII regulation.
    However, none of these federal rules extended OBD requirements to 
heavy-duty vehicles and engines. Today's action proposes that the 
existing light-duty OBD provisions be broadened to include both Otto-
cycle and diesel heavy-duty vehicles and engines up to 14,000 pounds 
GVWR. EPA is also proposing some revisions to existing light-duty OBD 
requirements applicable to diesel vehicles and trucks. These light-duty 
revisions are being proposed to maintain consistency across the 
existing light-duty diesel OBD requirements and today's proposed heavy-
duty diesel OBD requirements.
    The Agency believes it is appropriate to extend OBD requirements to 
include heavy-duty vehicles and engines for many reasons. In the past, 
heavy-duty diesel engines have relied primarily on in-cylinder 
modifications to meet emission standards. For example, emission 
standards have been met through changes in injection timing, piston 
design, combustion chamber design, use of four valves per cylinder 
rather than two valves, and piston ring pack design and location 
improvements. In contrast, the 2004 standards represent a significant 
technological challenge, and while manufacturers may make engine design 
changes to comply with those standards, EPA expects the 2004 standards 
will require EGR. Such ``add on'' devices can experience deterioration 
and malfunction that, unlike the engine design elements listed earlier, 
may go unnoticed by the driver. Because deterioration and malfunction 
of these ``add-on'' devices can go unnoticed by the driver, and because 
their sole purpose is emissions control, some form of detection is 
crucial. The Agency believes that such detection can be effectively 
achieved by employing a well designed OBD system.
    The same argument is true for Otto-cycle heavy-duty vehicles and 
engines. While emission control is managed both with engine design 
elements and ``add-on'' devices, the ``add-on'' devices, particularly 
the catalytic converter, are the primary emission control features. The 
Agency believes it is critical that the emission control system, 
particularly the ``add-on'' type systems, be monitored for proper 
operation to ensure that new vehicles and engines certified to the 
standards proposed today continue to meet those standards throughout 
their full useful life.
    Further, the industry trend is clearly toward increasing use of 
computer and electronic controls for both engine and powertrain 
management, and for emission control. In fact, the heavy-duty industry 
has already gone a long way, absent any government regulation, to 
standardize computer communication protocols.81 Computer and 
electronic control systems, as opposed to mechanical systems, provide 
improvements in many areas including, but not limited to, improved 
precision and control, reduced weight, and lower cost. However, 
electronic and computer controls also create increased difficulty in 
diagnosing and repairing the malfunctions that inevitably occur in any 
engine or powertrain system. Today's proposed OBD requirements would 
build on the efforts already undertaken by the industry to ensure that 
key emission related components will be monitored in future heavy-duty 
vehicles and engines and that the diagnosis and repair of those 
components will be as efficient and cost effective as possible.
---------------------------------------------------------------------------

    \81\ See ``On-Board Diagnostics, A Heavy Duty Perspective,'' SAE 
951947, and, ``Recommended Practice for a Serial Control and 
Communications Vehicle Network,'' SAE J1939.
---------------------------------------------------------------------------

    For these reasons, most manufacturers of vehicles, trucks, and 
engines have incorporated OBD systems that are capable of identifying 
when malfunctions occur, and in what systems. In the heavy-duty 
industry, those OBD systems traditionally have been geared toward 
detecting malfunctions causing driveability and/or fuel economy related 
problems. Without specific requirements for manufacturers to include 
OBD mechanisms to detect emission-related problems, those types of 
malfunctions that could result in high emissions without a 
corresponding adverse driveability or fuel economy impact could go 
unnoticed by both the driver and the repair technician. The resulting 
increase in emissions and detrimental impact on air quality could be 
avoided by incorporating an OBD system capable of detecting emission 
control system malfunctions.

[[Page 58509]]

2. CARB OBDII Requirements
    Current EPA OBD requirements apply only to light-duty vehicle and 
light-duty truck categories (less than 8500 pounds GVWR). In contrast, 
the CARB OBDII requirements include all light-duty categories and the 
CARB medium-duty category (vehicles/engines up to 14,000 pounds GVWR). 
As a result, while manufacturers of trucks and engines in the 8500 to 
14,000 pound GVWR category have not certified federally to OBD 
regulations, they have certified to the CARB OBDII requirements on all 
their California applications beginning with the 1996 model 
year.82
---------------------------------------------------------------------------

    \82\ This includes heavy-duty diesel and Otto-cycle applications 
which fall into EPA's light heavy- duty category.
---------------------------------------------------------------------------

    Furthermore, while these manufacturer's federal certification 
applications have not covered OBD requirements, the trucks and engines 
nonetheless contain OBD systems with varying levels of sophistication. 
This appears to be particularly true for diesel 
applications.83 While the sophistication of some of the OBD 
systems on existing federally certified heavy-duty vehicles and engines 
may be less than that required by today's proposal, EPA believes that 
the development work and lessons learned during implementation of CARB 
OBDII systems in California can be readily transferred to federal 
applications. With today's action, EPA proposes to implement OBD 
requirements for heavy-duty vehicles nationwide so that the benefits of 
OBD can be realized not only in California, but in the remaining 49 
states as well.
---------------------------------------------------------------------------

    \83\ See ``On-Board Diagnostics, A Heavy Duty Perspective,'' SAE 
951947; memo from T. Sherwood to Air Docket No. A-98-32, 
``Documentation of Sophisticated On-board Diagnostic (OBD) Systems 
on Current Heavy-duty Diesel Engines, dated March 17, 1999; and 
Internet websites for various heavy-duty diesel engine 
manufacturers: www.cummins.com; www.detroitdiesel.com; 
www.navistar.com.
---------------------------------------------------------------------------

3. Proposed Federal OBD Requirements
    Today's proposed OBD requirements are discussed in detail below. 
The requirements for heavy-duty Otto-cycle vehicles and engines are 
identical to those already in place for light-duty Otto-cycle vehicles 
and trucks. However, the proposed OBD requirements for heavy-duty 
diesel vehicles and engines differ somewhat from the current light-duty 
diesel requirements, specifically with regard to engine misfire and 
aftertreatment monitoring requirements. As a result, and because the 
Agency believes that the diesel provisions proposed today are more 
appropriate for diesel applications, today's notice also proposes that 
the light-duty diesel requirements be revised to be consistent with 
today's proposed heavy-duty diesel requirements.
    In general, the OBD system must monitor emission-related powertrain 
components for deterioration or malfunction causing emissions to exceed 
1.5 times the applicable standards. Upon detecting a malfunction, a 
dashboard MIL must be illuminated informing the driver of the need for 
repair. To assist the repair technician in diagnosing and repairing the 
malfunction, the OBD system must also incorporate standardization 
features (e.g., the diagnostic data link connector; computer 
communication protocols; etc.) the intent of which is to allow the 
technician to diagnose and repair any OBD compliant truck or engine 
through the use of a ``generic'' hand-held OBD scan tool.
4. Federal OBD Malfunction Thresholds and Monitoring Requirements
    EPA proposes that, beginning in the 2004 model year, heavy-duty 
vehicles and engines must be equipped with an OBD system capable of 
detecting and alerting the driver of the following emission-related 
malfunctions or deterioration as evaluated over the appropriate 
certification test procedure: 84
---------------------------------------------------------------------------

    \84\ The FTP minus the Supplemental FTP for chassis certified 
systems; the engine certification test procedure minus any 
supplemental test procedures for engine certified systems. While 
malfunction thresholds are based on certification test procedure 
emissions, this does not mean that OBD monitors need operate only 
during the test procedure. All OBD monitors that operate 
continuously during the test procedure should operate in a similar 
manner during non-test procedure conditions. The prohibition against 
defeat devices in Sec. 86.004-16 applies to these OBD requirements.
---------------------------------------------------------------------------

    (a) Catalyst or particulate trap deterioration or malfunction:
    Otto-cycle--before it results in an increase in NMHC 85 
emissions equal to or greater than 1.5 times the NMHC standard or FEL, 
as compared to the NMHC emission level measured using a representative 
4000 mile catalyst system; for engine certified systems, 
NMHC+NOX would be used in place of NMHC.
---------------------------------------------------------------------------

    \85\ As a point of clarification, federal emissions standards 
are expressed in terms of NMHC. Therefore, in order to remain 
consistent, all references to HC will be referred to as NMHC.
---------------------------------------------------------------------------

    Diesel-cycle--before it results in exhaust emissions exceeding 1.5 
times the applicable standard or FEL for NOX or PM. This 
monitoring would not need to be done if the manufacturer can 
demonstrate that deterioration or malfunction of the system will not 
result in exceedance of the threshold; however, the presence of the 
catalyst or particulate trap must still be verified. For engine 
certified systems, NMHC+NOX would be used in place of 
NOX.
    (b) Engine misfire:
    Otto-cycle--before it results in an exhaust emission exceedance of 
1.5 times the applicable standard or FEL for NMHC, CO or 
NOX; for engine certified systems, this would be 1.5 times 
NMHC+NOX or CO.
    Diesel-cycle--when lack of combustion occurs.
    (c) If the vehicle or engine contains an oxygen sensor, then oxygen 
sensor deterioration or malfunction before it results in an exhaust 
emission exceedance of 1.5 times the applicable standard or FEL for 
NMHC, CO or NOX; for engine certified systems, this would be 
1.5 times NMHC+NOX or CO.
    (d) If the vehicle or engine contains an evaporative emission 
control system, then any vapor leak in the evaporative and/or refueling 
system (excluding the tubing and connections between the purge valve 
and the intake manifold) greater than or equal in magnitude to a leak 
caused by a 0.040 inch diameter orifice; an absence of evaporative 
purge air flow from the complete evaporative emission control system. 
On vehicles with fuel tank capacity greater than 25 gallons, the 
Administrator would be required to revise the size of the orifice to 
the feasibility limit, based on test data, if the most reliable 
monitoring method available was unable to reliably detect a system leak 
equal to a 0.040 inch diameter orifice.
    (e) Any deterioration or malfunction occurring in a powertrain 
system or component directly intended to control emissions, including 
but not necessarily limited to, the EGR system, if equipped, the 
secondary air system, if equipped, and the fuel control system, 
singularly resulting in exhaust emissions exceeding 1.5 times the 
applicable emission standard or FEL for NMHC, CO, NOX, or 
diesel PM. For vehicles equipped with a secondary air system, a 
functional check, as described in paragraph (f) below, may satisfy the 
proposed requirements of this paragraph provided the manufacturer can 
demonstrate that deterioration of the flow distribution system is 
unlikely. This demonstration would be subject to Administrator approval 
and, if the demonstration and associated functional check are approved, 
the diagnostic system would be required to indicate a malfunction when 
some degree of secondary airflow is not detectable in the exhaust 
system during the check.
    (f) Any other deterioration or malfunction occurring in an 
electronic emission-related powertrain system or

[[Page 58510]]

component not otherwise described above that either provides input to 
or receives commands from the on-board computer and has a measurable 
impact on emissions; monitoring of components required by this 
paragraph would be satisfied by employing electrical circuit continuity 
checks and, wherever feasible, rationality checks for computer input 
components (input values within manufacturer specified ranges based on 
other available operating parameters), and functionality checks for 
computer output components (proper functional response to computer 
commands); malfunctions would be defined as a failure of the system or 
component to meet the electrical circuit continuity checks or the 
rationality or functionality checks.
    Upon detection of a malfunction, the MIL would be required to 
illuminate and a fault code stored no later than the end of the next 
driving cycle during which monitoring occurs provided the malfunction 
is again detected. Alternatively, upon Administrator approval, a 
manufacturer would be allowed to use a diagnostic strategy that employs 
statistical algorithms for malfunction determination (e.g., 
Exponentially Weighted Moving Averages (EWMA)). The Administrator 
considers such strategies beneficial for some monitors because they 
reduce the danger of illuminating the MIL falsely since more monitoring 
events are used in making pass/fail decisions. However, the 
Administrator would only approve such strategies provided the number of 
trips required for a valid malfunction determination is not excessive 
(e.g., six or seven monitoring events). Manufacturers would be required 
to determine the appropriate operating conditions for diagnostic system 
monitoring with the limitation that monitoring conditions are 
encountered at least once during the applicable certification test 
procedure or a similar test cycle as approved by the Administrator. 
This is not meant to suggest that monitors be designed to operate only 
under test procedure conditions, as such a design would not encompass 
the complete operating range required for OBD malfunction detection.
    As an option to the above requirements, EPA proposes to allow 
compliance demonstration according to the California OBDII 
requirements. This option has been available to light-duty vehicles and 
trucks since the implementation of the federal OBD program. This option 
allows manufacturers to concentrate on one set of OBD requirements for 
nationwide implementation (although federal OBD emission malfunction 
thresholds and monitoring requirements are essentially equivalent to 
those of the California OBDII regulation) and provides the highest 
level of OBD system effectiveness toward meeting nationwide clean air 
goals.
    However, there are differences between the California OBDII 
requirements and today's proposed EPA OBD requirements. The California 
OBDII regulation does not require catalyst or particulate trap 
monitoring for diesel-cycle vehicles and engines. Today's notice 
proposes such monitoring for EPA OBD systems. Therefore, if a 
manufacturer chooses the California OBDII compliance option for a 
diesel vehicle or engine, that manufacturer would still be required to 
satisfy the catalyst or particulate trap OBD monitoring requirements of 
today's proposal.
    The Agency requests comment on the above proposed OBD system 
requirements, the emission threshold levels, and the California OBDII 
compliance option. The Agency also wants to highlight and request 
comment on a very minor change meant to clarify and define the meaning 
behind rationality checks on applicable monitors. With this proposal, 
reflected in paragraph (f) above, and sections 86.004-17(b)(6) and 
86.1806-04(b)(6) of the proposed regulatory language, this definition 
would be changed from ``rationality checks for computer input 
components (input values within manufacturer specified ranges),'' to 
read, ``rationality checks for computer input components (input values 
within manufacturer specified ranges based on other available operating 
parameters).'' This proposed change would apply to all OBD systems--
light-duty, heavy-duty, chassis certified, engine certified, Otto-
cycle, diesel--and only serves to clarify; it would not constitute a 
new OBD requirement.
5. Proposed Standardization Requirements
    The light-duty OBD regulations contain requirements for 
standardization of certain critical aspects of the OBD system. These 
critical aspects include the design of the data link connector, 
protocols for on-board to off-board computer communication, formats for 
diagnostic trouble codes, and types of test modes the on-board system 
and the off-board scan tool must be capable of supporting. Today's 
action proposes that these standards, tabulated below, also be required 
for heavy-duty OBD systems. Today's action also proposes that, as an 
alternative, manufacturers have the option of standardizing their 
systems according to SAE J1939, ``Recommended Practice for a Serial 
Controlled Communications Vehicle Network.'' This alternative standard, 
SAE J1939, is a standard developed by the Society of Automotive 
Engineers (SAE) specifically for heavy-duty applications.

              Proposed Standards for Heavy-Duty OBD Systems
------------------------------------------------------------------------
          Proposed standards a            Alternative proposed standards
------------------------------------------------------------------------
SAE J1850: communications protocol.....  SAE J1939: communications
                                          protocol; data link connector;
                                          test modes and downloading
                                          protocols; format for
                                          diagnostics trouble codes.
ISO 9141-2: communications protocol....
SAE J1962: data link connector.........
SAE J1979: test modes and downloading
 protocols.
SAE J2012: format for diagnostics
 trouble codes.
------------------------------------------------------------------------
a SAE refers to the Society of Automotive Engineers; ISO refers to the
  International Organization of Standardization.

    The Agency requests comment on the appropriateness of the above 
standards and the need to incorporate other standards not mentioned 
above.
6. Deficiency Provisions
    Today's action proposes to apply the same deficiency provisions to 
heavy-duty OBD systems as currently apply to light-duty OBD systems. 
This would allow the Administrator to accept an OBD system as compliant 
even though specific requirements are not fully met. The deficiency 
provisions were first introduced on March 23, 1995 (60 FR 15242), and 
were recently revised on December 22, 1998 (63 FR 70681).

[[Page 58511]]

    The Agency is proposing these deficiency provisions because, 
despite the best efforts of manufacturers, many will likely need to 
certify vehicles with some sort of deficiency when unanticipated 
problems arise that can not be remedied in time to meet production 
schedules. Given the considerable complexity of designing, producing, 
and installing the components and systems that make up the OBD system, 
manufacturers of light-duty vehicles and trucks have expressed and 
demonstrated difficulty in complying with every aspect of the OBD 
requirements. The same difficulty is expected for heavy-duty vehicles 
and engines. While we believe that 100 percent compliance can be 
achieved, we also believe that some sort of relief should be provided 
to allow for certification of engines that, despite the best efforts of 
the manufacturers, have deficient OBD systems.
    The EPA ``deficiency allowance'' should only be seen as an 
allowance for minor deviations from the OBD requirements. In fact, EPA 
expects to implement this deficiency allowance primarily for software 
or calibration type problems, as opposed to cases where necessary 
hardware is at fault or is not present. EPA expects that manufacturers 
should have the necessary functioning OBD hardware in place, especially 
given the lead time afforded to OBD in this proposal, the extensive 
implementation of OBD that has already occurred on heavy-duty vehicles 
and engines absent any federal regulation, and the experience gained by 
those industry members affected by this proposal during several years 
of light-duty and California medium-duty OBD implementation.
    Furthermore, EPA does not intend to certify vehicles with federal 
OBD systems that have more than one OBD system deficiency, and EPA 
would not allow carryover of any deficiency to the following model year 
unless it can be demonstrated that correction of the deficiency 
requires hardware modifications that absolutely cannot be accomplished 
in the time available, as determined by the Administrator. These 
limitations are intended to prevent a manufacturer from using the 
deficiency allowance as a means to avoid compliance or delay 
implementation of any OBD monitors or to compromise the overall 
effectiveness of the OBD program. The Agency proposes that the 
``deficiency allowance'' be provided indefinitely, and requests comment 
on this proposal.
7. Applicability and Waivers
    Today's proposed federal OBD requirements would be implemented 
beginning with the 2004 model year, as described below for all heavy-
duty vehicles and engines for which emission standards are in place or 
are subsequently developed and promulgated by EPA. EPA proposes that 
there be a phase-in of the OBD requirements for heavy-duty vehicles up 
to 14,000 pounds GVWR, and for heavy-duty engines up to 14,000 pounds 
GVWR. The percentage phase-in schedule for such vehicles and engines 
will be 40/60/80/100 for the 2004/05/06/07 model years, respectively, 
based on projected sales. The phase-in percentages are determined 
separately for vehicles and for engines, but are not dependent on fuel.
    Specific to Otto-cycle OBD, during model years 2004 through 2006, 
EPA believes that any non-California Otto-cycle vehicles and engines 
having essentially equivalent counterparts certified for sale in 
California as compliant with the LEV emission standards and the CARB 
OBDII requirements could be readily certified for sale in the remaining 
49 states. That belief is based upon engineering judgement that such 
vehicles and engines will have essentially equivalent emission 
standards and OBD requirements. The sales mix of LEVs and ultra low 
emission vehicles (ULEVs) in California is 40 percent and 60 percent, 
respectively, with 100 percent of those in the less than 14,000 pound 
GVWR category in compliance with California's OBDII requirements. EPA 
considers the 40 percent LEV portion as easily certified for 49-state 
sales. The phased implementation of OBD compliance during the 
subsequent model years should provide sufficient lead time and 
flexibility to manufacturers.
    In summary, the proposed applicability and phase-ins for heavy-duty 
OBD compliance are as follows:

                             Compliance Phase-In for Today's Proposed OBD Provisions
----------------------------------------------------------------------------------------------------------------
              Model year                  Heavy-duty up to 14,000 pounds  GVWR           Diesel light duty
----------------------------------------------------------------------------------------------------------------
2004 MY..............................  --40% compliance                            --100% compliance.
                                       --deficiencies available                    --deficiencies available.
                                       --alternative fuel waivers available        --alternative fuel waivers
                                                                                    available.
                                       --CARB OBDII option available*              --CARB OBDII option
                                                                                    available.*
2005 MY..............................  --60% compliance                            --100% compliance.
                                       --deficiencies available                    --deficiencies available.
                                       --alternative fuel waivers available        --CARB OBDII option
                                                                                    available.*
                                       --CARB OBDII option available*
2006 MY..............................  --80% compliance                            --same as 2005 MY.
                                       --deficiencies available
                                       --alternative fuel waivers available
                                       --CARB OBDII option available*
2007+ MY.............................  --100% compliance                           --same as 2005 MY.
                                       --deficiencies available
                                       --CARB OBDII option available*              .............................
----------------------------------------------------------------------------------------------------------------
*But diesels must meet EPA aftertreatment monitoring requirements.

    For heavy-duty vehicles and engines up to 14,000 pounds GVWR 
operating on alternative fuel, EPA would grant OBD waivers during 
alternative fuel operation through the 2006 model year to the extent 
that manufacturers can justify the inability to fully comply with any 
of today's proposed OBD requirements. 86 Such inability 
would have to be based upon technological infeasibility, not resource 
reasons. Further, any heavy-duty vehicles and

[[Page 58512]]

engines that are subsequently converted for operation on alternative 
fuel would not be expected to comply with today's proposed OBD 
requirements if the non-converted vehicle or engine does not comply. In 
other words, if the vehicle or engine never completes any assembly 
stage in OBD compliance, it need not comply with today's proposed OBD 
requirements while operating on the alternative fuel. If the vehicle or 
engine does complete any assembly stage with a compliant OBD system, it 
would have to comply with today's OBD requirements while operating on 
the fuel of original intent and, to the extent feasible, while 
operating on the alternative fuel. For these latter situations, EPA 
could grant waivers through the 2006 model year if the manufacturer can 
show it is infeasible to meet the requirements. Beginning in the 2007 
model year, all heavy-duty alternative fueled vehicles and engines up 
to 14,000 pounds GVWR would have to be fully compliant during both 
operation on the fuel of original intent and alternative fuel.
---------------------------------------------------------------------------

    \86\ Note that this provision currently exists for light-duty 
vehicles and trucks operating on alternative fuel through the 2004 
model year; that existing provision does not change with today's 
proposal.
---------------------------------------------------------------------------

    EPA requests comments on all aspects of these OBD implementation 
and phase-in provisions. In particular, EPA requests comments on the 
phase-in percentages and their application to vehicles and engines 
separately. The phase-in is proposed in this way because the regulatory 
structure contains engine based OBD requirements in 40 CFR subpart A 
and chassis based OBD requirements in 40 CFR subpart S. Therefore, the 
phase-in percentages would have to be determined independently as they 
apply to the OBD systems certified according to the provisions of the 
specific subpart. If this creates unexpected burdens, or eliminates 
intended flexibilities, comments should explain how and suggest 
alternate phase-in language.
8. Certification Provisions
    The OBD certification information requirements of today's proposal 
are consistent with the Compliance Assurance Programs 2000 (CAP 2000) 
rulemaking discussed above. The Part 1 Application must include, for 
each OBD system: A description of the functional operating 
characteristics of the diagnostic system; the method of detecting 
malfunctions for each emission-related powertrain component; and a 
description of any deficiencies including resolution plans and 
schedules. Anything certified to the California OBDII regulations would 
be required to comply with California ARB information requirements. EPA 
may consider abbreviating the OBD information requirements through 
rulemaking if it gains confidence that manufacturers are designing OBD 
systems that are fully compliant with all applicable regulations.
    During EPA certification of vehicles optionally certified to the 
California OBDII regulation, EPA may conduct audit and confirmatory 
testing consistent with the provisions of the California OBDII 
requirements. Therefore, while the Agency will consider California 
certification in determining whether to grant a federal certificate, 
EPA may also elect to conduct its own evaluation of that OBDII system. 
While it is unlikely, EPA may make a compliance determination that is 
not identical to that of the California Air Resources Board.
    Further, the Agency fully intends to allow a chassis certified and 
chassis demonstrated OBD system to fulfill any demonstration 
requirements of an engine certified OBD system (i.e., ``drop-in'' 
demonstration). Likewise, we fully intend to allow an engine certified 
and engine demonstrated OBD system to fulfill the demonstration 
requirements of a chassis certified OBD system. However, any chassis 
certified system would have to incorporate transmission diagnostics 
even though the ``dropped-in'' engine system may not have been 
certified with them.
    In other words, if a manufacturer demonstrates OBD compliance using 
a chassis certified system, then wishes to employ engineering judgement 
in demonstrating compliance of an engine certified OBD system, the 
Agency would accept such a demonstration provided sound engineering 
judgement is employed. The same would be true for an engine to chassis 
situation (note the transmission diagnostic stipulation stated above). 
This allowance is perhaps most applicable to Otto-cycle OBD systems, 
but it would also apply for diesel systems. The Agency intends to make 
this allowance because OBD systems tend to be essentially identical in 
concept and approach across the product line of any given manufacturer, 
even though specific calibrations may change from engine to engine or 
model to model. The compliance allowance discussed here requires the 
manufacturer to rigorously demonstrate its OBD concept and approach on 
one engine or model, but allows the manufacturer to apply that 
demonstration via engineering judgement to the different engine and 
powertrain calibrations used across its fleet.

H. Durability Procedures

    Under the current certification regulations, manufacturers develop 
deterioration factors based on testing of development engines and 
emissions control systems. Because emissions control efficiency 
generally decreases with the accumulation of service on the engine, the 
regulations require that a DF be used in conjunction with engine test 
results as the basis for determining compliance with the standards. The 
regulations require that the manufacturer develop an appropriate DF, 
which is then subject to review by EPA in the certification process. 
These deterioration factors are applied to low mileage emissions levels 
of certification engines in order to predict emissions at the end of 
the engines' useful life. The emissions level after the deterioration 
factor is applied is the engine certification level, which must be 
below the standard for the engine to be certified. For engines equipped 
with aftertreatment (e.g., catalysts), the DF must be 
``multiplicative'' (i.e., a factor that can be multiplied by the low 
mileage emissions level of the certification engine to project 
emissions at the end of the engine useful life). For engines lacking 
aftertreatment (e.g., most current diesels), the DF must be 
``additive'' (i.e., a factor that can be added to the low mileage 
emissions level of the certification engine to project emissions at the 
end of the engine useful life).
    Manufacturers have argued that EPA should not propose a standard on 
the basis of current low engine certification levels, even though these 
levels are supposed to reflect anticipated emissions levels over the 
life of the engine. Manufacturers also noted that the deterioration 
factors capture deterioration for vehicles under typical use and not 
severe use. Thus, the manufacturers stated that they account for severe 
deterioration by targeting certification levels at half the standard. 
EPA has given full consideration to each of these concerns in 
developing the proposed standards.
    EPA believes that the manufacturer's durability process should 
result in the same or greater level of deterioration than is observed 
in-use for a significant majority of their vehicles, rather than simply 
matching the average in-use deterioration. This is especially important 
considering that incomplete vehicles and vehicles over 14,000 pounds 
GVWR are more likely to be work vehicles and operated under more severe 
conditions a greater percentage of their useful lives. In recent 
certification applications (for the 1998 and 1999 model years, for 
example), manufacturers have reported NOX DFs on the order 
of 1.2 to 1.6 for heavy-duty Otto-cycle engines. Manufacturers have

[[Page 58513]]

indicated on several occasions that they certify at levels of half the 
standard to address more severe in-use operation than is represented by 
their deterioration factors. Based on manufacturer comments, if a 
durability process is designed to represent the deterioration of a 
significant majority of engines within an engine family, EPA would 
expect manufacturers to calculate a multiplicative deterioration factor 
which is higher than current DFs, on the order of 2.0 or more. 
Manufacturers also presented EPA with an analysis of engine emissions 
standards, which is discussed in detail in the Technological 
Feasibility section below. The catalyst deterioration rates used in 
that analysis indicate that the deterioration factor could be higher 
than two in some cases.
    EPA believes that it is important for certification levels 
(emissions tests adjusted by the DF) to represent anticipated in-use 
emissions levels of a significant majority of in-use engines. This will 
continue to be a key aspect of EPA's compliance programs. Deterioration 
factors are also used during production line testing to verify the 
emissions performance of production engines. Finally, the ABT program 
relies on certification data as the basis for determining credits. 
Although Otto-cycle engine manufacturers have not made wide use of the 
ABT program to date, EPA expects more use of the program in future 
years due to the new more stringent emissions standards and new ABT 
flexibilities.
    EPA is proposing today that the compliance provisions for heavy-
duty engines contained in 40 CFR part 86, subpart A would continue to 
apply to HDVs subject to the engine-based standards, with modifications 
designed to ensure that the durability demonstration procedures used by 
manufacturers in the certification process, and deterioration factors 
calculated by means of these procedures, predict the emission 
deterioration of a significant majority of in-use engines to be covered 
by the procedure.
    The deterioration factor determination procedures in the 
regulations are proposed to be modified to specify that emission 
control component aging procedures will predict the deterioration of 
the significant majority of in-use engines over the breadth of their 
product line which would ultimately be covered by this procedure 
(manufacturers would be expected to show that their durability programs 
cover on the order of ninety percent or higher of the distribution of 
deterioration rates experienced by vehicles in actual use). In 
addition, manufacturers would be required to calculate multiplicative 
DFs by dividing high mileage exhaust emissions by the low milage 
exhaust emissions (e.g., emissions at the useful life mileage by 
exhaust emissions at 4,000 miles).87 This change only adds 
specificity to the regulations so that DFs are calculated using a 
consistent and credible methodology. These proposed modifications to 
the engine-based HDV compliance procedures would be effective for any 
engine family generating ABT credits prior to the 2004 model year. EPA 
requests comment on the proposed modifications to the engine-based 
compliance program durability procedures.
---------------------------------------------------------------------------

    \87\ Manufacturers are not required to accumulate actual mileage 
on vehicles or engines in order to determine a deterioration rate. 
In many cases, the accumulation of mileage (or ``service'') is 
simulated by various ``bench aging'' techniques that allow the 
process to consume less time and resources than accumulating actual 
mileage.
---------------------------------------------------------------------------

I. Non-Conformance Penalties

    Non-conformance penalties are monetary penalties that manufacturers 
can pay instead of complying with an emission standard. (See CAA 
section 206(g) and 40 CFR part 86, subpart L.) In the final rule for 
the 2004 standards for diesel heavy-duty engines, we stated that 
provisions related to NCPs would be addressed in the 1999 Review. (See 
62 FR 54700; October 21, 1997.) In order to establish NCPs for a 
specific standard, EPA must find that: (1) Substantial work will be 
required to meet the standard for which the NCP is offered; and (2) 
there is likely to be a ``technological laggard'' (i.e., a manufacturer 
that cannot meet the standard because of technological (not economic) 
difficulties and, without NCPs, might be forced from the marketplace). 
We also must determine compliance costs so that appropriate penalties 
can be established.
    For diesel heavy-duty engines, the most recent NCPs established 
were for the 1994 particulate standard (0.10 g/bhp-hr) and the 1998 
NOX standard (4.0 g/bhp-hr). NCPs have not been established 
to date for Otto-cycle heavy-duty engines. NCPs were used extensively 
by manufacturers of highway heavy-duty engines in the late 1980s, prior 
to the implementation of our averaging, banking and trading program. 
Since that time, however, their use has been rare. We believe 
manufacturers have taken advantage of the averaging, banking and 
trading program as a preferred alternative to incurring monetary 
losses.
    At this time, EPA has insufficient information indicating that both 
of the criteria described above are met for diesel or Otto-cycle heavy-
duty engines. While we believe that substantial work will be required 
to meet the 2004 standards, we have no information indicating that a 
technological laggard is likely to exist. We also believe that the 
existing NOX and particulate averaging, banking and trading 
program already provides considerable flexibility to meet the emission 
standards. Therefore, we are not proposing NCPs as part of today's 
proposed program, but we request comment on whether NCPs are necessary 
for the 2004 standards for diesel or Otto-cycle heavy-duty engines. 
Particularly, commenters should address the two criteria described 
above for establishing NCPs (``substantial work'' and ``technological 
laggard''). We recognize that it may be premature for manufacturers to 
comment on these criteria, since implementation of the 2004 standards 
is still five years away. It may be more prudent to consider addressing 
NCPs in a future action as we approach implementation of the 2004 
standards.

V. Additional Heavy-Duty Engine Provisions Under Consideration

    In addition to the provisions proposed in this notice, EPA is 
currently reviewing several related regulatory issues concerning 
control of emissions from heavy-duty vehicles and engines. As discussed 
in section X below, EPA is reviewing the feasibility of more stringent 
standards for heavy-duty vehicles and engines in the future, and the 
impact of fuel quality on that question. In addition, EPA believes that 
there are several provisions related to the need for an effective 
emissions control program that will benefit from further evaluation and 
development prior to proposal. EPA intends to explore these provisions 
further in the coming months and publish a notice of proposed 
rulemaking dealing with these issues in a separate regulatory process 
within the next 12 months. We would expect to follow this with a final 
rule in early 2001.
    In particular, there are four issues--a revised definition of rated 
speed, OBD requirements for engines used in vehicles above 14,000 GVWR, 
a manufacturer-based in-use test program, and application of the NTE 
approach to heavy-duty Otto-cycle engines--that we intend to deal with 
in the separate process. As explained below, EPA believes that there 
are several open issues and/or informational gaps that need to be 
reviewed regarding these issues prior to proposal of regulations.

[[Page 58514]]

As EPA wishes to complete the current rulemaking process as quickly as 
possible, EPA believes that it is appropriate to proceed with the 
current rulemaking without addressing these four issues at this time. 
This will allow us to gather information and work with interested 
parties in a separate process regarding these issues.
    In a letter to EPA dated July 1, 1999, the Engine Manufacturers 
Association (EMA) committed to ``work diligently and cooperatively'' 
with EPA and CARB to resolve the open questions in a timely 
fashion.88 EMA's letter outlined a process that does not 
preclude implementation of these programs in the 2004 model year, and 
in fact, highlights model year 2004 implementation as a stated goal of 
this cooperative effort. A cooperative approach to data-collecting, 
analysis, and problem-solving can help in developing the proposals for 
these issues. EPA will work with all parties involved, including states 
and environmental organizations, to develop robust, creative, 
environmentally protective and cost-effective proposals addressing 
these issues.
---------------------------------------------------------------------------

    \88\ Letter from Mr. Jed R. Mandel, Neal Gerber & Eisenberg, to 
Margo Oge, Office of Mobile Sources, July 1, 1999. Available in the 
public docket for review.
---------------------------------------------------------------------------

A. Revision to the Definition of Rated Speed

    The definition of rated speed, where speed is the angular velocity 
of an engine's crankshaft (usually expressed in revolutions per minute, 
or rpm) is an important aspect of the existing FTP for on-highway HD 
diesel engines. The rated speed definition is important to the FTP 
because it is used to define the range of engine speeds over which the 
engine will be exercised during the test. The regulations require 
engine manufacturers to declare rated speeds consistent with the 
regulation for their engines for the purpose of testing on the FTP 
cycle; however, past experience has raised our concern that selection 
of rated speed for the purpose of FTP testing is not being performed 
consistently across the entire HD industry. We are concerned that some 
manufacturers have declared rated speeds which result in the FTP test 
being run over a speed and torque range which are not representative of 
the operating characteristics of a particular engine family, in order 
to influence the parameters under which the engine family is certified. 
Under the existing transient HD FTP, manufacturers could receive a 
NOX emission benefit if they declared a rated speed that was 
higher than that envisioned under the regulations.
    The on-highway HD diesel regulation defines rated speed as the 
speed at which the manufacturer specifies the maximum rated horsepower 
from the engine. The torque and rpm points used on the FTP are 
determined in part from the measured rated rpm, which in turn is 
determined using the rated speed or the calculated speed, whichever 
yields the higher speed (see 40 CFR 1330-90(g)). The calculated rated 
speed is determined by averaging the minimum and maximum speeds at 
which 98 percent of maximum power is generated. This definition was 
sufficient when it was developed in the late 1970's for engines with 
mechanical fuel injection and mechanical speed governors. For these 
engines, the slope of the power vs. speed lug curve remained monotonic 
and positive as speed increased until the mechanical governor engaged. 
At this point of governor control, the slope of the curve rapidly 
became sharply negative as speed increased toward the maximum governed 
speed. Therefore, maximum power occurred at nearly only one speed, and 
this speed was clearly identifiable by the breakpoint in the lug curve 
where the governor caused a rapid change in slope from positive to 
sharply negative. Engine manufacturers typically reported this speed as 
rated speed for sales and service literature as well as for FTP 
testing. Furthermore, the calculated rated speed calculation returned 
nearly the same speed, because of the nature of these lug curves with 
respect to the calculation.
    With the advent of electronically fuel injected and governed 
engines, manufacturers began to design engines with high torque rises 
to meet customer demands. High torque rise engines often have lug 
curves in which the maximum power-speed point occurs at a much lower 
speed than mechanical engines. This power point is often at the 
maximum, where to the left and right of the maxima, the slope is 
slightly positive and negative, respectively. As speed increases beyond 
this maximum, the power does not taper off sharply, as in the case of 
mechanical engines. The electronic engines, on the other hand, have 
gradually negative slopes, and sometimes they even have a slight 
inflection to zero slope before the electronic speed governor engages. 
These characteristics render the rated speed calculation less 
meaningful because the two 98 percent speed points are often at very 
different speeds along the gradual positive and negative slopes around 
the actual maximum power-speed. Because of these characteristics of 
electronic engines, EPA believes there now exists a need for an 
objective and singular definition of rated speed for the purposes of 
FTP testing.
    We believe a new definition of rated speed is warranted, and that a 
new definition should be both objective and representative of in-use 
operation. The rated speed definition should be objective and should 
result in a single value for a given engine family. This would avoid 
inequitable testing. The rated speed definition should also result in 
an FTP test cycle which exercises the engine's emission control system 
over a range of engine speeds and loads that are representative of in-
use operation.
    The Agency is not proposing a new definition of HD rated speed in 
today's action. While the Agency believes there are issues associated 
with the current definition with rated speed, there are a number of 
issues with developing a new definition which have not yet been 
resolved. We intend to include a proposal for a new definition in a 
forthcoming proposal, and we intend to work with the industry, the 
California Air Resources Board, and other interested parties in the 
upcoming months to develop such a proposal. The Agency recently 
proposed a definition of rated speed for nonroad diesel marine engines 
which may be an appropriate blueprint for the on-highway industry (see 
63 FR 68528, October 21, 1998). The reader is encouraged to examine the 
proposed nonroad diesel marine definition as one possible approach for 
the on-highway HD diesel industry.

B. A Manufacturer-Based In-Use Testing Program for Heavy-Duty Engines

    To help ensure that heavy-duty engines meet applicable emission 
standards throughout their useful lives, the Agency must have 
reasonable certainty that the emissions measured in the laboratory 
during certification of prototype engines reflect those experienced 
during real world operation of actual in-use engines. We believe that a 
manufacturer-run in-use testing program is an important way to ensure 
that the 2004 emission standards for heavy-duty engines are achieved in 
actual use throughout their useful lives, as required by the Act. We 
believe that manufacturers are best suited to run such an in-use 
testing program for several reasons. First, we understand that 
manufacturers commonly evaluate in-use engines on the road to support 
their engine development process and troubleshoot customer concerns. 
For manufacturers already conducting such in-use engine performance 
testing, we see an in-use testing program as adding an emissions 
measurement component.

[[Page 58515]]

Second, we also understand that, through these product development and 
customer service/product warranty activities, manufacturers maintain a 
close relationship with the purchasers of their engines. We believe 
that this close customer relationship makes engine manufacturers best 
suited to locate and obtain in-use vehicles for emissions testing. For 
anyone other than the manufacturer, it would be difficult to locate in-
use vehicles powered by a particular engine family, because heavy-duty 
trucks travel throughout the country. Since these trucks often are 
integral to business operations, owners may be unwilling to part with 
them for testing by entities other than the manufacturer. However, we 
expect that some owners, especially those of larger fleets, will view 
participation of their vehicles in an in-use testing program as an 
opportunity to establish an even stronger relationship with the 
manufacturer. This arrangement with the manufacturer could lead to 
other benefits to the owner, such as an opportunity to better 
communicate product needs.
    Such a program would require manufacturers to measure emissions 
from a sample of in-use vehicles. Several issues need to be reviewed 
prior to proposal. These include the test procedures used for the in-
use testing, the number of vehicles or engines that would be required 
for testing, and whether such testing will be done on engines (or 
vehicles) run in a laboratory or vehicles tested on the road. In the 
past, the laboratory testing of HD engines has been difficult for a 
number of reasons, with cost being one of the most significant 
barriers. In recent years, important advancements have been made in a 
number of emission measurement technologies as well as on-board engine 
management technologies which could allow for the development of a new 
and innovative in-use testing program for HD engines.
    Today's action does not contain a proposal for manufacturer in-use 
testing of HD engines, with the exception of those HD Otto-cycle 
chassis certified engines which would be covered by the CAP 2000 
provisions of today's proposal (see section IV.E.5--Compliance 
Assurance Program). The Agency does not believe that it currently has 
enough information to determine the most appropriate parameters of a 
manufacturer-run in-use testing program. However, the Agency intends to 
work with the engine manufacturers, CARB, the emissions measurement 
industry, and other interested parties over the next several months to 
explore these issues in order to achieve the goal of a meaningful in-
use testing program which would be run by the engine manufacturers.

C. On-Board Diagnostics for Heavy-Duty Engines and Vehicles Above 
14,000 Pounds GVWR

    Similar to the expected benefits of having OBD requirements on 
light-duty vehicles and trucks, and heavy-duty vehicles and engines up 
to 14,000 pounds GVWR, we believe that there are similar benefits to 
having OBD requirements for applications over 14,000 pounds GVWR. 
However, there are many potential issues associated with applying OBD 
requirements to applications above 14,000 pounds GVWR that have not 
been of similar concern regarding smaller vehicles. For example, trucks 
this large tend to be equipped with power take-off units that are 
operable a substantial portion of the time. Examples are refrigerator 
trucks, garbage trucks, or cement mixers. Such vehicles often use 
engine power to operate the refrigeration unit, the compactor, or the 
cement mixer, in addition to powering the vehicle as it drives down the 
road. Such devices, powered off the engine, are referred to as ``power 
take-off units.'' Both CARB and EPA regulations currently allow 
disablement of most OBD monitors during power take-off unit operation. 
This has been of little concern for smaller vehicles, because of the 
very small percentage of vehicles in the 14,000 lb. GVWR and under 
weight range that use such units for a substantial portion of their 
operation. However, this approach to OBD monitoring during power take-
off unit operation is difficult for larger engines that use power take-
off units during substantial portions of their operation. It makes 
little sense to require a sophisticated OBD system on a vehicle if it's 
allowed to remain disabled during essentially its entire operation due 
to the power take-off unit.
    This represents just one issue which, while it can be dealt with 
effectively, requires more time and cooperative efforts with industry 
and others to develop a meaningful and effective set of OBD 
regulations. Another such issue is the lack of vertical integration in 
the heavy-duty industry, particularly in the classes above 14,000 
pounds GVWR. This lack of vertical integration creates increased 
difficulty associated with bringing together engine, transmission, 
chassis, and safety related diagnostics because so many different 
manufacturers are involved in creating the end product. For that 
reason, we are not proposing OBD requirements for engines above 14,000 
pounds GVWR at this time. We will gather further information and work 
closely with interested parties during the coming months to develop 
proposed OBD requirements for such engines.

D. Applying the Not-To-Exceed Approach and Emission Limits to Heavy-
Duty Otto-Cycle Engines

    Though today's action contains supplemental standards for HD diesel 
engines (Not-to-Exceed test and associated standards, Supplemental 
Steady State Test and associated standards, and the Load Response Test) 
today's action does not include similar provisions for HD Otto-cycle 
engines. As noted earlier, EPA's primary interest is developing an 
effective means of controlling actual in-use emissions across a broad 
range of in-use operation, a concern that extends to Otto-cycle engines 
as much as it does diesel engines. We believe that the same concerns 
which necessitate supplemental standards and test procedures for HD 
diesel engines may also exist for HD Otto-cycle engines, and that 
measures similar to those proposed for diesels to assure effective in-
use control may also be warranted for Otto-cycle engines. We believe 
that the NTE approach is a valuable concept for accomplishing this goal 
for heavy-duty Otto-cycle engines, just as it is for diesels. However, 
we have not had as much time to consider such an approach for Otto-
cycle engines, and data collection enabling appropriate setting of an 
NTE emission limit and definition of an Otto-cycle NTE zone is still 
underway as of today's proposal. Like other issues described in this 
section, we intend to work with the engine manufacturers, CARB, and 
other interested parties over the next several months to develop an NTE 
or similar approach to achieve the goal of assuring effective in-use 
control of HD Otto-cycle engines over a broad range of in-use 
operation.

VI. Are the Proposed Requirements Technologically Feasible?

A. 2004 Emission Standards for Heavy-Duty Diesel Engines

    Today's proposal contains a reaffirmation of the 2004 
NMHC+NOX standards as well as several supplemental standards 
and test cycles for 2004 model year HDDE;

--2.4 g/bhp-hr NMHC + NOX or 2.5 g/bhp NMHC + NOX 
with a limit of 0.5 g/bhp-hr on NMHC on the existing Federal Test 
Procedure
--Emission standards of 1.0 times the FTP standards on the new 
Supplemental Steady-state Test Cycle

[[Page 58516]]

--Emission standards of 1.25 times the FTP standards under the new Not-
to-Exceed test zone

    Based on the information currently available to EPA, we believe 
manufacturers are making significant progress towards meeting the 2004 
standards contained in today's proposal, and we believe the standards 
are technologically feasible. Chapter 3 of the draft RIA for this 
proposal contains a detailed description of the technologies we expect 
engine manufacturers to utilize to meet the proposed 2004 standards. 
The discussion here is a summary of the draft RIA discussion; the 
reader should refer to the RIA for a more detailed discussion. We 
request comment on this discussion and on our proposed feasibility 
assessment.
    HD diesel engines being certified to the 1998 U.S. standards are 
already utilizing several advanced technologies, including high-
pressure fuel injection systems, redesigned combustion chambers, air-
to-air aftercoolers, waste-gated turbochargers and electronic controls. 
These technologies have allowed engine manufacturers to meet the 
emission standards which went into effect in 1998, while continuing to 
provide end users with improved fuel economy, improved durability, and 
improved driveability. The Agency expects to see incremental 
improvements in some of these strategies between now and 2004, but 
these improvements alone will not lower NMHC+NOX emissions 
to the levels needed to meet the 2004 standards, and also comply with 
the current PM standard. To meet the 2004 standards, EPA expects that, 
in addition to the aforementioned strategies, manufacturers will 
utilize EGR, variable geometry turbo-chargers, fuel injection rate 
shaping, and possibly exhaust aftertreatment.
1. Probable Emission Control Strategies
    Exhaust Gas Recirculation. EGR is the recirculation of exhaust gas 
from a point in an engine's exhaust system to a point in the intake 
system. EGR is used to decrease nitric oxide (NO) emissions, the 
primary species in diesel oxides of nitrogen. EGR dilutes intake air 
with combustion products, namely carbon dioxide (CO2) and 
water vapor. These diluents decrease the adiabatic stoichiometric flame 
temperature for a given mass of fuel and oxygen burned.\89\ This 
decrease in temperature exponentially decreases the oxidation rate of 
dissociated nitrogen (N) to NO.\90\ EGR also decreases the mole 
fraction of oxygen, which proportionally decreases the oxidation rate 
of N to NO.\91\
---------------------------------------------------------------------------

    \89\ Heywood J.B.: Internal Combustion Engine Fundamentals, 
McGraw-Hill, Inc, New York, p. 590, 1988.
    \90\ Dodge L.G., D.M. Leone, D.W. Naegeli, D.W. Dickey, K.R. 
Swenson: ``A PC-Based Model for Predicting NOX Reductions 
in Diesel Engines,'' SAE paper 962060, p.149, 1996.
    \91\ Ibid.
---------------------------------------------------------------------------

    EGR is very effective at decreasing NOX. Laboratory 
studies have shown that EGR can reduce NOX emissions by up 
to 90 percent at light load and up to 60 percent at full load near 
rated speed.\92\ Additional studies have shown similar reductions at 
other speeds and loads.\93\ However, because EGR decreases the overall 
rate of combustion in the cylinder, EGR tends to increase PM emissions 
and brake specific fuel consumption (BSFC). Furthermore, if EGR is not 
cooled before it is introduced to the intake system, it will reduce the 
density of the intake charge, and thus decrease the volumetric 
efficiency of the engine, which will decrease maximum power and 
increase BSFC. Hot EGR also offsets EGR's beneficial effect on 
combustion temperature because hot EGR increases the initial 
temperature of the air charge. Finally, EGR without additional boost 
air can result in incomplete combustion and an increase in PM 
emissions. Through proper EGR system design, however, researchers have 
demonstrated that these undesirable effects of EGR can be minimized so 
that the 2004 emission standards can be met, including fully offsetting 
the potential increase in PM to enable engines to continue to comply 
with the 0.1 g/bhp-hr standard.\94\ The draft RIA contains additional 
discussion of how these issues are being addressed.
---------------------------------------------------------------------------

    \92\ Dickey D.W., T.W. Ryan III, A.C. Matheaus: ``NOX 
Control in Heavy-Duty Engines--What is the Limit?'', SAE paper 
980174, 1998. Dickey; and, Zelenka P., H. Aufinger, W. Reczek, W. 
Cartellieri: ``Cooled EGR--A Key Technology for Future Efficient HD 
Diesels,'' SAE paper 980190, 1998.
    \93\ Kohketsu S., K. Mori, K. Sakai, T. Hakozaki: ``EGR 
Technologies for a Turbocharged and Intercooled Heavy-Duty Diesel 
Engine,'' SAE paper 970340, 1997; Baert R., D.E. Beckman, A.W.M.J. 
Veen: ``EGR Technology for Lowest Emissions,'' SAE paper 964112, 
1996; and, Heavy-duty Engine Working Group, Mobile Source Technical 
Advisory Subcommittee of the Clean Air Act Advisory Committee, 
``Phase 2 of the EPA HDEWG Program--Summary Document'', available in 
EPA Air Docket A-98-32.
    \94\ Dickey D.W., T.W. Ryan III, A.C. Matheaus: ``NOX 
Control in Heavy-Duty Engines-What is the Limit?'', SAE paper 
980174, 1998.
---------------------------------------------------------------------------

    From a design perspective, EGR poses several challenges for it to 
be technologically feasible. First, a sufficient positive pressure 
difference must exist between the point in the exhaust system where the 
exhaust gas is extracted and the point in the intake system where it is 
introduced. Second, under most conditions, EGR should be cooled for 
best performance. Third, the rate of EGR must be controlled accurately, 
and the control system must respond quickly to changes in engine 
operation.\95\ As discussed in more detail in the draft RIA, the Agency 
believes engine and component manufacturers have either resolved these 
design challenges, or have made significant progress towards a 
resolution. EPA believes the remaining challenges can be resolved 
considering the lead time remaining to engine manufacturers, and the 
use of ABT to introduce the technology across the product line over a 
period of time.
---------------------------------------------------------------------------

    \95\ Zelenka P., H. Aufinger, W. Reczek, W. Cartellieri: 
``Cooled EGR--A Key Technology for Future Efficient HD Diesels,'' 
SAE paper 980190, 1998.
---------------------------------------------------------------------------

    Fuel Injection Rate-shaping. Another key emission control strategy 
that EPA expects heavy-duty diesel engine manufacturers to use to meet 
the 2004 emission standards is fuel injection rate shaping. Injection 
rate shaping has been shown to simultaneously reduce NOX by 
20 percent and PM by 50 percent under some conditions.96 It 
has also been shown to reduce BSFC by up to 10 percent without 
increasing NOX emissions.97 However, it can also 
lead to increases in smoke emissions and may not be as effective on 
low-NOX engines equipped with EGR. Fuel injection rate 
shaping refers to precisely controlling the rate of fuel injected into 
the cylinder on a crank-angle by crank-angle resolution. Specific rate-
shaping methods include pilot injection where a pilot quantity of fuel, 
typically less than two percent of the total fuel charge, is injected 
at some crank angle before the main injection event.98 Split 
fuel injection refers to splitting, more or less evenly, the main 
injection into two or more separate injections (split injection is also 
referred to as pilot injection). Other methods include ramping the main 
injection event so that it resembles a triangular profile, rather than 
a conventional, square-shaped profile. Effective injection rate-shaping 
systems modulate the fuel injection timing, pressure, rate, and 
duration independent of engine speed and load. This characteristic of 
the fuel system

[[Page 58517]]

implies that it should be mechanically de-coupled from the engine. 
Timing is then achieved, presumably, by electronic control.
---------------------------------------------------------------------------

    \96\ Dickey D.W., T.W. Ryan III, A.C. Matheaus: ``NOX 
Control in Heavy-Duty Engines--What is the Limit?'', SAE paper 
980174, 1998.
    \97\ Boehner W., K. Hummel: ``Common Rail Injection System for 
Commercial Diesel Vehicles'', SAE paper 970345, 1997; and Uchida N, 
K. Shimokawa, Y. Kudo, M. Shimoda: ``Combustion Optimization by 
Means of Common Rail Injection System for Heavy-Duty Diesel 
Engines'', SAE paper 982679, 1998.
    \98\ Boehner W., K. Hummel, ``Common Rail Injection System for 
Commercial Diesel Vehicles'', SAE 970345, 1997.
---------------------------------------------------------------------------

    Rate shaping is used to control the rate of combustion within the 
cylinder. By controlling combustion rate, the rate of pressure and 
temperature rise is controlled. Therefore, rate shaping controls 
NOX formation by one of the same mechanisms as EGR; it is 
used to lower peak combustion temperatures. Rate shaping can affect the 
time and temperature at which combustion ends, therefore it can also 
lower PM emissions by enhancing the mechanisms of in-cylinder soot 
oxidation.99
---------------------------------------------------------------------------

    \99\ Heywood, J.B., Internal Combustion Engine Fundamentals, 
McGraw-Hill, Inc., New York, p. 643-644, 1988.
---------------------------------------------------------------------------

    Several manufacturers and fuel system suppliers have demonstrated 
fuel injection systems that can achieve effective rate shaping. The 
three most common systems are the common rail; the mechanically 
actuated electronically controlled unit injector (MEUI); and the 
hydraulically actuated, electronically controlled unit injector (HEUI). 
These systems are described in more detail in the draft RIA (see 
Chapter 3).
    Several studies have suggested rate-shaping methods to achieve 
emissions benefits. Researchers have reported decreased NOX 
and PM emissions at intermediate speeds and loads by optimizing 
reduced-rate pilot injection with a high-pressure main injection, and 
one report suggested a strategy at high loads.100 
101 102 At intermediate loads, burnt pilot fuel 
is used as a torch to decrease ignition delay of the main injection 
event. This lowers peak flame temperatures and, thus, NOX 
formation. At high loads the ignition delay is not as significant, but 
a very early pilot event (>20 deg. before top-dead center) can be used 
to distribute low-temperature burnt gas in the cylinder, similar to 
EGR. This method can be optimized to decrease NOX, PM, and 
BSFC simultaneously. Other reports have suggested ramped main injection 
at high loads and high speeds to decrease NOX, square main 
injection at peak torque to decrease PM, and split injection at idle to 
decrease volatile PM (i.e. white smoke).
---------------------------------------------------------------------------

    \100\ Ikegami, M., K. Nakatani, S. Tanaka, K. Yamane: ``Fuel 
Injection Rate Shaping and Its Effect on Exhaust Emissions in a 
Direct-Injection Diesel Engine Using a Spool Acceleration Type 
Injection System'', SAE paper 970347, 1997.
    \101\ Uchida N, K. Shimokawa, Y. Kudo, M. Shimoda: ``Combustion 
Optimization by Means of Common Rail Injection System for Heavy-Duty 
Diesel Engines'', SAE paper 982679, 1998.
    \102\ Dickey D.W., T.W. Ryan III, A.C. Matheaus: 
``NOX Control in Heavy-Duty Engines--What is the 
Limit?'', SAE paper 980174, 1998.
---------------------------------------------------------------------------

    EPA expects manufacturers to utilize fuel injection rate shaping to 
meet 2004 emission standards. EPA believes the strategy is 
technologically feasible because fuel injection rate shaping is used to 
a limited extent today to meet 1998 emissions standards, and several 
manufacturers have announced the introduction in the next few years of 
next-generation fuel injection systems with rate shaping ability. 
Furthermore, EPA expects even greater emission control through rate 
shaping as manufacturers continue to develop advanced fuel systems and 
control algorithms. We request comment on the feasibility of rate 
shaping and EGR in the 2004 time frame.
2. Feasibility of 2004 HD Diesel Standards
    EPA expects manufacturers to utilize a combination of technologies 
in order to meet the proposed 2004 standards, such as cooled EGR 
systems with VNT and advanced fuel injection with rate shaping 
capability. The draft RIA for this rule, as well as the final RIA for 
the 1997 rule, contains a summary of the emission performance of a 
number of technology combinations which have been published in the 
referred literature in the past several years. These published results 
are on a variety of laboratory test cycles, including the U.S. 
transient heavy-duty FTP, the old European ECE-R49 13 mode steady-state 
cycle, and the new European Euro III steady-state cycle (which the U.S. 
EPA new supplemental steady-state cycle in this proposal is based on).
    The published results referenced in the draft RIA show a waste-
gated turbocharged engine with a high-pressure loop EGR system and a 
MEUI fuel system achieving NOX levels on the new Euro III 
cycle at levels between 1.83 and 3.24 g/bhp-hr (the 1.83 level resulted 
in a 2.4 percent increase in fuel consumption), with corresponding PM 
levels between 0.15 and 0.06 g/bhp-hr. Results on a HD diesel engine 
equipped with a VNT, high-pressure loop EGR system, and high pressure 
fuel injection system achieved results on the older European ECE-R49 
cycle for NOX between 1.80 and 2.24 g/bhp-hr (the 1.80 level 
resulted in a 2.3 percent increase in fuel consumption). For both tests 
a PM level of 0.08g/bhp-hr was reported. Results referenced in the 
final RIA for the 1997 rule include a study which resulted in 
HC+NOX levels of 2.54 g/bhp-hr on the U.S. HD transient FTP, 
this engine was equipped with an EGR system, a rate-shaping fuel 
injection system, and an oxidation catalyst and was run on a low sulfur 
fuel.
    The Agency believes the technologies described above and in the 
draft RIA will provide the emission reductions necessary to allow 
engine manufacturers to meet the proposed 2004 standards. These control 
technologies have been demonstrated to provide significant emission 
reductions under both transient and steady-state test conditions. 
Steady-state and transient operation are represented in this proposal 
by the existing FTP, and the new NTE, LRT, and supplemental steady-
state cycle.
    In order to meet the proposed NTE standards, manufacturers will 
need to perform emission mapping of each engine family in order to 
insure that over the NTE control zone, optimization of the emission 
control system provides sufficient control of the emission map for each 
pollutants which will maintain levels below the 1.25 times the FTP 
standard over a 30 second interval. EPA believes the emission control 
technologies discussed previously as well as in the RIA are capable of 
providing this level of emission control. The emission control 
capacities of these technologies are applicable to NTE and LRT test 
conditions in the same manner as they apply to the transient and 
steady-state test conditions. The less stringent levels for NTE should 
also provide a level of assurance to manufacturers.
    As discussed, several publicly available studies have shown results 
which approach or surpass the proposed standards, though several 
indicate fuel economy penalties on the order of two percent. 
Significant development and demonstration of cooled EGR, VNT, and fuel 
injection systems has been performed in the past two years. Engine 
manufacturers have four years of lead time available in which to 
continue to fully develop and optimize these control technologies in 
order to meet the proposed standards, as well as to minimize or 
eliminate the fuel economy penalty associated with some technologies. 
Finally, the 1997 rulemaking put in place ABT provisions for HD diesel 
engines for the 2004 standards. These ABT provisions provide engine 
manufacturers with considerable flexibility in determining how they 
will meet the proposed standards on a corporate average, and thus 
provides the manufacturers with some level of flexibility in 
determining how to apply the range of technologies available across 
their product line.
    Technology combinations of cooled EGR systems, VNTs, and advanced 
fuel injection systems have been

[[Page 58518]]

demonstrated in the past several years which are capable of meeting the 
proposed 2004 standards. Engine manufacturers have an additional four 
years of lead time to develop and optimize these control systems. EPA 
has considered the well known inverse relationship between 
NOX and PM. As discussed previously, integrated emission 
control technology packages (cooled EGR, VNT, and advanced fuel 
injection system) have been demonstrated to significantly reduce 
NOX with a minimal increase in PM. Considering the several 
years of additional lead time available to manufacturers, achievement 
of the 2004 standards is clearly feasible. In addition, as discussed in 
the draft RIA, other control methods, such as aftertreatment, though 
unnecessary to meet the 2004 standards, could be used to further reduce 
emissions. The ABT provisions provide engine manufacturers some 
flexibility in determining the appropriate mix of technologies across 
their product line. For these reasons, EPA fully anticipates that 
engine manufacturers will meet the 2004 standards contained in today's 
proposal.

B. 2004 Emission Standards for Heavy-Duty Otto-Cycle Vehicles and 
Engines

    This section discusses the current technologies being used by 
manufacturers and the key technology changes we believe would be 
available to meet the proposed 2004 vehicle and engine standards. 
Technological feasibility of the exhaust emissions standards is 
presented first, followed by analyses for ORVR controls. Manufacturers 
would ultimately decide what is best for their individual product 
lines. Further information on the various available technologies and 
EPA's technological feasibility assessment is contained in the 
Technological Feasibility section of the Regulatory Impact Analysis. We 
request comment on the following discussion and on our feasibility 
assessment for heavy-duty Otto-cycle vehicles and engines.
1. Current Technologies
    Gasoline engine manufacturers are already producing heavy-duty 
engines that achieve a level of emission control better than the 
control required by current standards. Table 12 provides a list of some 
key technologies currently being used for HD engine emissions control. 
Manufacturers have introduced improved systems as they have introduced 
new or revised engine models. These systems can provide very good 
emissions control and many engines are being certified to levels of 
less than half the current standards. Many of the technologies have 
been carried over from light-duty applications.
Table 12.--Key Technologies for Current Heavy-Duty Otto-Cycle Engines
Sequential Fuel Injection/electronic control
    3 way catalyst
    Pre and post catalyst heated oxygen sensors
Electronic EGR
Secondary air injection
Improved electronic control modules

    Improving fuel injection has been proven to be an effective and 
durable strategy for controlling emissions and reducing fuel 
consumption from gasoline engines. Improved fuel injection will result 
in better fuel atomization and a more homogeneous charge with less 
cylinder-to-cylinder and cycle-to-cycle variation of the air-fuel 
ratio. These engine performance benefits will increase as technology 
advances allow fuel to be injected with better atomization. Increased 
atomization of fuel promotes more rapid evaporation by increasing the 
surface area to mass ratio of the injected fuel. This results in a more 
homogeneous charge to the combustion chamber and more complete 
combustion. Currently, sequential multi-port fuel injection (SFI) is 
used in most, if not all, applications under the proposed standards 
because of its proven effectiveness.
    One of the most effective means of reducing engine-out 
NOX emissions is EGR. By recirculating spent exhaust gases 
into the combustion chamber, the overall air-fuel mixture is diluted, 
lowering peak combustion temperatures and reducing NOX. 
Exhaust gas recirculation is currently used on heavy-duty Otto-cycle 
engines as a NOX control strategy. Many manufacturers now 
use electronic EGR in place of mechanical back-pressure designs. By 
using electronic solenoids to open and close the EGR valve, the flow of 
EGR can be more precisely controlled.
    EPA believes that the most promising overall emission control 
strategy for heavy-duty Otto-cycle engines is the combination of a 
three-way catalyst and closed loop electronic control of the air-fuel 
ratio. Control of the air-fuel ratio is important because the three-way 
catalyst is effective only if the air-fuel ratio is at a narrow band 
near stoichiometry. For example, for an 80 percent conversion 
efficiency of HC, CO, and NOX with a typical three-way 
catalyst, the air-fuel ratio must be maintained within a fraction of 
one percent of stoichiometry. During transient operation, this minimal 
variation cannot be maintained with open-loop control. For closed-loop 
control, the air-fuel ratio in the exhaust is measured by an oxygen 
sensor and used in a feedback loop. The throttle position, fuel 
injection, and spark timing can then be adjusted for given operating 
conditions to result in the proper air-fuel ratio in the exhaust. Most 
if not all engines have already been equipped with closed loop 
controls. Some engines have been equipped with catalysts that achieve 
efficiencies in excess of 90 percent. This is one key reason engine and 
vehicle certification levels are very low. In addition, electronic 
control can be used to adjust the air-fuel ratio and spark timing to 
adapt to lower engine temperatures, therefore controlling HC emissions 
during cold start operation.
    All HD Otto-cycle engines are already equipped with three-way 
catalysts. Engines may be equipped with a variety of different catalyst 
sizes and configurations. Manufacturers choose catalysts to fit their 
needs for particular vehicles. Typically, catalyst systems are a single 
converter or two converters in series or in parallel. A converter is 
constructed of a substrate, washcoat, and catalytic material. The 
substrate may be metallic or ceramic with a flow-through design similar 
to a honeycomb. A high surface area coating, or washcoat, is used to 
provide a suitable surface for the catalytic material. Under high 
temperatures, the catalytic material will increase the rate of chemical 
reaction of the exhaust gas constituents.
    Significant changes in catalyst formulation have been made in 
recent years and additional advances in these areas are still possible. 
Platinum, Palladium and Rhodium (Pt, Pd, and Rh) are the precious 
metals typically used in catalysts. Historically, platinum has been 
widely used. Today, palladium is being used much more widely due to its 
ability to withstand very high exhaust temperatures. In fact, some HD 
vehicles currently are equipped with palladium-only catalysts. Other 
catalysts contain all three metals or contain both palladium and 
rhodium. Some manufacturers have suggested that they will use Pd/Rh in 
lieu of tri-metal or conventional Pt/Rh catalysts for underfloor 
applications. Improvements in substrate and washcoat materials and 
technology have also significantly improved catalyst performance.
2. Chassis-Based Standards
    EPA is proposing to extend the California LEV-I MDV standards 
nationwide. California began requiring some vehicles to meet LEV 
standards in 1998 and the phase-in will be complete

[[Page 58519]]

in 2001. The technological feasibility assessment and technology 
projections are based primarily on the mix of technologies being used 
to achieve California LEV emissions levels.
    Of the anticipated changes, enhancements to the catalyst systems 
are expected to be most critical. Catalyst configurations are likely to 
continue to vary widely among the manufacturers because manufacturers 
must design the catalyst configurations to fit the vehicles. One 
potential change is that manufacturers may move the catalyst closer to 
the engine (close-coupled) or may place a small catalyst close to the 
engine followed by a larger underfloor catalyst. These designs provide 
lower cold start emissions because the catalyst is closer to the engine 
and warms up more quickly. Typically, the catalyst systems used in HD 
applications have a large total volume but with lower precious metal 
content per liter compared to light-duty catalyst systems. For 2004, 
EPA projects an increase in overall precious metal loading of about 50 
percent. EPA does not expect significant increases in total catalyst 
volume.
    Calibration changes will also be important. The engine and catalyst 
systems must be calibrated to optimize the performance of the systems 
as a whole. Post catalyst oxygen sensors will allow further air fuel 
control. Manufacturers are moving to more powerful computer systems and 
EPA expects this trend to continue. Other technologies such as 
insulated exhaust systems may also be used in some cases to reduce cold 
start emissions.
    HD vehicles in California have typically been certified with full 
life emissions levels in the 0.3-0.5 g/mile range for NOX 
and the 0.1-0.3 g/mile range for NMOG. These levels are well within the 
LEV standards and provide manufacturers with a compliance cushion. EPA 
expects manufacturers to sell these vehicles or very similar vehicles 
nationwide to meet the proposed EPA standards.
3. Engine-Based Standards
    Currently, most engine families are certified with emissions levels 
of less than half the standard. Only one engine family is certified 
with NOX emissions levels within 10 percent of the current 
4.0 g/bhp-hr NOX standards. Manufacturers have begun to 
apply advanced system designs to their heavy-duty applications. 
Recently introduced engine families have been certified with emissions 
levels of 0.5 g/bhp-hr combined NMHC+NOX.103 
These engines and systems feature precise air/fuel control and superior 
catalyst designs comparable to the catalyst systems being used in the 
California LEV program. Based on industry input, we believe that 
manufacturers will continue the process of replacing their old engine 
families with advanced engines over the next several years. As new and 
more advanced engines are introduced, EPA anticipates that they will be 
capable of achieving the proposed standards.
---------------------------------------------------------------------------

    \103\ EPA is not proposing to set the standard at this level 
because EPA recognizes that a manufacturer needs to design their 
technology to build in sufficient compliance margin, based on the 
technology and standards at issue here.
---------------------------------------------------------------------------

    Manufacturers have stated on several occasions that they target 
emissions certification levels of about half the standard, due to the 
potential for in-use deterioration of catalysts and oxygen sensors. 
Catalysts experience wide variations in exhaust temperature due to the 
wide and varied usage of vehicles in the field. Some vehicles may 
experience more severe in-use operation than is represented by the 
durability testing currently conducted for engine certification. 
Manufacturers have argued that EPA should not set new standards based 
on certification data because certification levels do not account for 
severe in-use deterioration. Based upon these comments EPA would expect 
that manufacturers would certify engines at about 0.5 g/bhp-hr 
NMHC+NOX in order to ensure compliance with the 1.0 
g/bhp-hr standard.
    Catalyst systems with increased precious metal loading will be a 
critical hardware change for meeting the proposed engine standards. 
Optimizing and calibrating the catalyst and engine systems as a whole 
will also be important in achieving the proposed standards. Increased 
use of air injection to control cold start emissions may also be 
needed, especially to reduce NMHC emissions during cold start 
operation. Also, improved EGR systems and retarded spark timing may be 
needed to reduce engine out NOX emissions levels.
    Catalyst system durability is a key issue in the feasibility of the 
standards. Historically, catalysts have deteriorated when exposed to 
very high temperatures and this has long been a concern for heavy-duty 
work vehicles. Manufacturers have often taken steps to protect 
catalysts by ensuring exhaust temperatures remain in an acceptable 
range. Catalyst technologies in use currently are much improved over 
the catalysts used only a few years ago. The improvements have come 
with the use of palladium, which has superior thermal stability, and 
through much improved washcoat technology. The catalysts have been 
shown to withstand temperatures typically experienced in HD 
applications. Manufacturers also continue to limit exhaust temperature 
extremes not only to protect catalyst systems but also to protect the 
engine.
    In addition to general comments noted above regarding the need for 
compliance cushion, manufacturers presented EPA with an analysis of the 
Otto-cycle engine emissions standards for 2004.104 The 
analysis assumed:
---------------------------------------------------------------------------

    \104\ ``September 15, 1998 Meeting with Engine Manufacturers 
Association (EMA)'', EPA Memorandum from John W. Mueller, Mechanical 
Engineer, to docket A-95-27, November 4, 1998. Docket A-95-27, 
Docket # IV-E-26.
    \105\ [Reserved]
---------------------------------------------------------------------------

     Worst-case NOX catalyst efficiency of 90.9 
percent at the end of the engine's useful life
     Worst-case engine-out NOX level of 12 g/bhp-hr
     A cushion of .3 g/bhp-hr for engine variability and a 
safety margin of 20 percent of the standard
     Tailpipe NMHC levels of 15 percent of the NOX 
level (.26 g/bhp-hr)
    Based on these assumptions, manufacturers recommended a 2.0 g/bhp-
hr  NMHC plus NOX standard, according to the following 
methodology.

Variability=0.3 g/bhp-hr  (eq. 1)
Safety Margin=20% (NOX level)
    (eq. 2)
NMHC Level=14.8 % (NOX Level)
    (eq. 3)
Combined NMHC+NOX Standard=NOX Level+NMHC Level  
(eq. 4)
NOX Level=Post-catalyst NOX 
rate+Variability+Safety Margin  (eq. 5)
(Step 1) Post-catalyst NOX rate=(1-conversion 
efficiency) x Engine-Out NOX level=(1-0.91) x 12 g/bhp-
hr=1.09 g/bhp-hr  (eq. 6)
(Step 2) Putting eq. (1), (2), and (6) into equation (5)--
NOX Level=1.09 g/bhp-hr+0.3 g/bhp-hr+0.2 x NOX 
Level  (eq. 5b)
(Step 3) Solving Equation (5b) for NOX Level gives--
NOX Level=(1.09 g/bhp-hr+0.3 g/bhp-hr)/(1-0.2)=1.74 g/bhp-hr
(Step 4) Placing the results from (Step 3) into Equation 5 gives--NMHC 
Level=14.8% NOX Level=0.148 x 1.74 g/bhp-hr=0.26 g/bhp-hr
(Step 5) Placing the results from (Step 3) and (Step 4) into equation 
(1) gives: Combined NMHC+NOX Standard=0.26 g/bhp-hr+1.74 g/
bhp-hr=2 g/bhp-hr

Manufacturers noted that a catalyst efficiency of about 97 percent 
would be

[[Page 58520]]

needed to meet a 1.0 g/bhp-hr standard and that their assessments of 
post-2000 catalysts indicate worst case performance well below this 
level. The 2.0 g/bhp-hr standard recommended by manufacturers seems to 
indicate that compliance cushions greater than half the standard are 
needed.
    The deterioration factor for the engine and catalyst system in the 
above analysis would be on the order of four or five.106 
This is extremely high compared to the deterioration factors currently 
used for certification which are typically between one and two. While 
EPA understands that current deterioration factors may represent 
typical deterioration and not severe deterioration, EPA believes that 
deterioration factors of four or five are unreasonably high and 
unlikely. EPA would expect a deterioration factor representing more 
severe operation to be closer to two, which is consistent with 
manufacturers' previous statements of certifying with certification 
levels of half the standard to allow for needed compliance margin.
---------------------------------------------------------------------------

    \106\ During developmental testing the deterioration factor is 
determined by dividing the full life emissions level for an engine 
by the low mileage emissions level. The low mileage level of the 
certification engine is then multiplied by the deterioration factor 
to predict full life emissions.
---------------------------------------------------------------------------

    Manufacturers state that their catalyst assumptions represented 
catalyst deterioration based on worst case vehicle operation (highly 
loaded operation, high exhaust temperatures). Details of the catalyst 
were not available except that manufacturers stated that the catalyst 
represented post-2000 catalyst technology. Due to the lack of detail, 
it is difficult to evaluate the assumption. However, EPA believes that 
this assumption is somewhat conservative given the recent developments 
in catalyst technology, the lead time available, and methods available 
to protect catalysts under worst case vehicle operation.
    Engine-out NOX levels are also critical to the analysis. 
In their analysis, manufacturers assumed engine-out NOX 
levels of 12 g/bhp-hr, based on manufacturer development data for one 
engine. EPA does not believe that the engine-out NOX level 
of 12 g/bhp-hr is a reasonable or representative assumption. Other 
available data indicates that several engines have engine-out 
NOX emissions well below this level in the 6 to 10 g/bhp-hr 
range. Also, a previous assessment of engine standards presented to EPA 
by one manufacturer assumed much lower engine-out NOX 
levels.107 EPA does not believe that the current standards 
have encouraged manufacturers to place a high priority on engine-out 
emissions levels. In fact, one manufacturer has removed EGR systems 
from its engines. For recent engines, catalysts have provided the 
majority of needed emissions control.
---------------------------------------------------------------------------

    \107\ The engine-out data and the details of this analysis are 
considered Confidential Business Information.
    \108\ [Reserved]
---------------------------------------------------------------------------

    EPA also further considered the engine variability factor of 0.3 g/
bhp-hr built into the manufacturers' analysis. The analysis as 
presented assumes a 12 g/bhp-hr engine-out NOX level. 
Manufacturer data for the developmental engine suggests that 12 g/bhp-
hr is the worst case engine-out level anticipated (the actual highest 
test point recorded was 12.65). It appears to EPA that manufacturers 
double counted engine variability by using the worst case engine data 
and an engine variability factor. Using engine-out NOX 
levels of 12 g in the analysis but without the engine variability 
factor yields a NOX + NMHC level of 1.6 g/bhp-hr. Without 
including a safety margin, which may be appropriate considering the 
analysis is already based on worst case engine and catalyst 
assumptions, the level would be 1.3 g/bhp-hr. To reach the 1.0 g/bhp-hr 
level with this engine and a 20 percent safety margin, a catalyst 
efficiency of 94 percent would be needed, according to the following 
assumptions and methodology.

Combined NMHC + NOX Standard = 1.0 g/bhp-hr
Engine-Out NOX level (worse-case) = 12 g/bhp-hr
Safety Margin = 20 % (NOX level) (eq. 1)
NMHC Level = 14.8 % (NOX Level) (eq. 2)
Combined NMHC + NOX Standard = NOX Level + NMHC 
Level (eq. 3)
NOX Level = Post-catalyst NOX rate + Safety 
Margin (eq. 4)
Post-catalyst NOX rate = (1-Conversion Efficiency) x Engine-
Out NOX level (eq. 5)
(Step 1) Equation (3) can be solved for NOX Level--Combined 
NMHC + NOX Standard = NOX Level + NMHC Level 1.0 
g/bhp-hr = NOX Level + 0.148 NOX Level 
NOX Level = 0.871 g/bhp-hr
(Step 3) Placing the results from Step (1) and Equation (1) into 
Equation (4), and solving for Post-catalyst NOx rate gives--
NOX Level = Post-catalyst NOX rate + Safety 
Margin 0.871 g/bhp-hr = Post-catalyst NOX rate + 0.2  x  
0.871 g/bhp-hr Post-catalyst NOX rate = 0.697 g/bhp-hr
(Step 4) Placing the results from Step (3) into Equation 5 and solving 
for Conversion Efficiency gives:
    Post-catalyst NOX rate = (1-Conversion Efficiency)  x  
Engine-Out NOX level
    0.697 g/bhp-hr = (1--Conversion Efficiency)  x  12 g/bhp-hr
    Conversion Efficiency = 0.94 = 94%

    EPA believes that the proposed standards would require 
manufacturers to focus some effort on engine-out emissions control and 
that engine-out NOX levels in the 6 to 8 g/bhp-hr range are 
reasonably achievable. Some engines are already in this range. For 
other engines, some recalibration of engine systems including the EGR 
system and perhaps some modest hardware changes to those systems would 
be necessary. EGR plays a key role in reducing engine-out 
NOX, and system redesign may allow more effective use of 
this technology.
    When coupled with a catalyst with worst case efficiencies in the 91 
to 93 percent range, these engines could achieve the proposed 
standards. Of course with higher catalyst efficiencies, manufacturers 
would not have to achieve lower NOX engine-out levels. 
Catalyst efficiencies of about 93 percent would allow manufacturers to 
maintain compliance margins in the range of 25 and 45 percent of the 
standard. EPA believes these margins are sufficient considering the 
analysis is also based on worst case catalyst efficiencies.
    To help address phase in concerns that could arise for 
manufacturers, EPA is proposing a modified ABT program for engines, as 
described above. The ABT program can be an important tool for 
manufacturers in implementing a new standard. The program allows 
manufacturers to comply with the more stringent standards by 
introducing emissions controls over a longer period of time, as opposed 
to during a single model year. Manufacturers plan their product 
introductions well in advance. With ABT, manufacturers can better 
manage their product lines so that the new standards don't interrupt 
their product introduction plans. Also, the program also allows 
manufacturers to focus on higher sales volume vehicles first and use 
credits for low sales volume vehicles. EPA believes manufacturers have 
significant opportunity to earn credits in the pre-2004 time frame.
    Considering all of these factors, EPA believes that the 1.0 g/bhp-
hr NMHC+NOX standard is an appropriate standard for HD Otto-
cycle engines in the 2004 time frame; however, we are requesting 
comment on a standard in

[[Page 58521]]

the range of 1.0 to 1.5 g/bhp-hr. Certification levels of 0.5 g/bhp-hr 
NMHC+NOX have been achieved on recently introduced engines 
of varied sizes. EPA believes that the proposed standard provides 
sufficient opportunity for manufacturers to maintain a reasonable 
compliance margin. As manufacturers continue with normal product plans 
between now and 2004, improved engines will continue to replace older 
models. The ABT program is available for manufacturers who have not 
completely changed over to new engine models by 2004. ABT provides 
manufacturers with the opportunity to earn credits prior to 2004 and 
use the credits to continue to offer older engine models that have not 
yet been redesigned or retired by 2004.
    EPA requests comments on the above analyses and directs the reader 
to the Regulatory Impact Analysis for further detail on technological 
feasibility. EPA continues to seek further information on emissions 
control and engine system capability and durability. EPA requests 
comment on the feasibility of the proposed standards and requests data 
which would help the Agency further evaluate advanced system 
durability.
4. Onboard Refueling Vapor Recovery
    EPA believes that today's proposed ORVR requirements are 
technologically feasible. In its previous ORVR rulemaking, EPA elected 
to apply ORVR requirements only to LDVs and LDTs (see 59 FR 16262, 
April 6, 1994). As previously discussed in the section on the proposed 
ORVR standards, EPA chose at the time of the original rulemaking not to 
apply ORVR to HDVs because of concerns over secondary manufacturers, 
different fuel tank designs for larger HDVs than for LDVs and LDTs, and 
the fact that HDVs are certified under an engine-based testing program. 
These three issues are addressed in section IV.E.4.b) of this preamble. 
In the original ORVR rule, however, EPA analyzed the potential 
application of ORVR to all HDVs. In that analysis EPA concluded that 
ORVR is technologically feasible for application to HDVs. EPA concluded 
that the systems which would be required for the covered subset of HDVs 
would be essentially the same as those for LDVs and LDTs. Such systems 
have already been successfully implemented on a portion of the LDV 
fleet. The Agency is aware of no information on fundamental changes to 
HDV fuel system design which would cause it to believe that the 
original analysis is no longer valid. EPA requests comment on this 
view.
    ORVR systems must meet certain basic requirements in order to be 
effective at controlling refueling emissions. In general, they must 
provide for the routing of displaced vapors from the fuel tank to the 
engine rather than allowing them to escape uncontrolled to the 
atmosphere. This will likely be accomplished through the use of 1) a 
fillneck seal which prevents the vapors from escaping out the fillneck, 
2) a fuel tank vent mechanism, to allow for the controlled routing of 
the vapors from the fuel tank, 3) vapor lines for transporting vapors, 
4) a canister containing activated carbon to temporarily store the 
vapors, and 5) a purge system to regenerate the canister and route the 
vapors to the engine.
    The major components of an ORVR system are already in place on HDVs 
in response to EPA's enhanced evaporative emission requirements (see 58 
FR 16002, March 24, 1993). The primary differences between an enhanced 
evaporative control system and an ORVR system lie in the need to 
prevent vapors from escaping via the fillneck during a refueling event, 
and the fact that the vapor flow rates out of the fuel tank are much 
higher during refueling than during vehicle operation and diurnal 
events that enhanced evaporative systems are designed to control. A 
complete discussion of the major components of an ORVR system and how 
they differ from those in a system designed to comply with the enhanced 
evaporative requirements is contained in the Regulatory Impact 
Analysis.

C. On-Board Diagnostics

    For Otto-cycle vehicles and engines, the most difficult monitors to 
implement are those for the catalyst system, the evaporative emission 
control system, and engine misfire. While each of these monitors poses 
technological challenges, none of them pose technological feasibility 
concerns. Rather than concerns over technological feasibility, EPA 
expects concerns, where today's proposal applies to Otto-cycle vehicles 
and engines, over resource constraints for OBD calibration and 
associated verification testing.
    EPA does not consider resource constraints a feasibility issue, nor 
does EPA believe the manufacturers will be constrained by today's OBD 
provisions. EPA believes this is true for both the Otto-cycle and the 
diesel OBD requirements. Since the 1996 model year, manufacturers have 
been equipping their vehicles and engines with OBD systems essentially 
identical to those being proposed today. This is true federally for all 
vehicles above 8500 pounds GVWR, and in California for all vehicles and 
engines above 14,000 pounds GVWR. The Agency believes that the four 
year lead time within today's proposal matched with the OBD phase-in of 
40/60/80/100 percent provides adequate lead time to apply the real 
world tested OBD system technology to their new sales fleet above 
14,000 pounds GVWR without resource difficulties.
    The transmission represents an area of potential concern for engine 
certified as opposed to chassis certified Otto-cycle and diesel 
engines. Typically, the engine manufacturer certifies and sells its 
engine, without an associated transmission, to a chassis manufacturer. 
The chassis manufacturer then ``mates'' the engine to a transmission 
purchased from a transmission manufacturer representing a third 
industry party. The regulations proposed today require that chassis 
certified systems employ transmission diagnostics, but would not 
require that engine certified systems employ transmission diagnostics.
    EPA believes that it is reasonable to expect that electronically 
controlled transmissions will be designed with some level of 
diagnostics to ensure proper operation. In addition, the Agency expects 
that those transmissions will utilize industry standard communication 
protocols allowing the transmission and the engine control computers to 
communicate, and allowing any transmission-related OBD codes to be 
downloaded via the standard diagnostic data link connector without 
engine manufacturer involvement. If either of these expectations is 
inaccurate, EPA requests information concerning the likely operational 
characteristics of electronic transmissions. If EPA's expectations are 
accurate, we request comment on the appropriateness of the engine 
certified OBD requirements, Otto-cycle and diesel, being limited to 
engine diagnostics, and simply requiring that transmissions comply with 
industry standard communication protocols.
    Specific to diesel vehicles and engines, the Agency believes there 
are three areas of concern associated with technological feasibility: 
EGR monitoring; misfire monitoring; and, aftertreatment monitoring. 
With respect to EGR monitoring, the primary concern is expected to be 
the cooling componentry of a cooled EGR system. Other aspects of the 
EGR system, such as activation of the EGR valve, verification of proper 
flow, etc., can be accomplished as is already being done on Otto-cycle 
and diesel vehicles and

[[Page 58522]]

engines under 14,000 pounds GVWR.109 However, the cooling 
system presents a new challenge. The Agency believes monitoring of the 
cooling system is feasible by employing temperature sensors to ensure 
proper EGR cooling (heat transfer) given existing engine conditions, 
and coolant flow. If the cooling system becomes fouled, its ability to 
transfer heat from the exhaust gases to the coolant will be diminished 
and a resultant temperature inconsistency should be observed. Likewise, 
if coolant ceases to flow through the cooling system, a resultant 
temperature inconsistency should be observed. In fact, EPA believes 
that manufacturers will monitor EGR cooling system performance absent a 
requirement to do so. As discussed in Chapter 3 of the Draft Regulatory 
Impact Analysis for today's proposal, manufacturers will be designing 
their EGR systems to cool the EGR to specific design targets to 
optimize engine performance and to minimize condensation of sulfuric 
acid. The only way to ensure that engine performance is being optimized 
is to monitor the performance of the EGR system and compare it to the 
specific design targets.
---------------------------------------------------------------------------

    \109\ Current EGR monitoring systems may use the existing intake 
air temperature sensor--opening the EGR valve should result in an 
increased intake air temperature. Systems may also use an intake air 
pressure sensor--opening the EGR valve will change the intake air 
pressure.
---------------------------------------------------------------------------

    As for diesel misfire monitoring, the Agency believes that the 
proposed requirement is technologically feasible. In fact, 
manufacturers are certifying compliant diesel misfire monitors for sale 
in California on vehicles and engines under 14,000 pounds GVWR. We 
believe, like CARB, that diesel misfire is an air quality concern. 
Also, we believe that most users of diesel vehicles and engines under 
14,000 pounds GVWR, particularly vehicles and engines less than 10,000 
pounds GVWR, will not notice or may ignore diesel misfires. In 
contrast, we believe that most users of engines above 14,000 pounds 
GVWR will notice and not ignore misfires. We believe this is true 
because most of these engines are driven by professionals for whom 
minimizing fuel consumption and maximizing engine performance is a 
primary business concern. Conversely, most vehicles and engines under 
14,000 pounds GVWR, particularly vehicles and engines under 10,000 
pounds GVWR, are driven by individuals as personal transportation or 
for small business use. Such drivers are probably less familiar with 
the day-to-day operating characteristics of their engines and are 
probably less concerned with fuel consumption and engine performance. 
Nonetheless, we are interested in comments on the misfire monitoring 
requirements of today's proposal. In addition, we request data, such as 
warranty data, showing misfire rates and possible differences between 
engines above and below 14,000 pounds GVWR.
    With respect to diesel catalyst monitoring, the Agency expects such 
monitoring to be conducted using temperature sensing devices to detect 
an exotherm within the aftertreatment device. The Agency requests 
comment on this expectation and on the probable magnitude of the 
exotherm. Comments should consider whether limiting the operating modes 
during which the exotherm is measured (for example, during steady-state 
operation at a specific engine load, etc.) might increase the accuracy 
of the monitoring method. Comments should also consider whether, given 
the provision for back pressure monitoring in lieu of performance 
monitoring provided test data demonstrate that emissions will not 
exceed today's proposed malfunction threshold, manufacturers will even 
have to employ diesel catalyst emission performance monitors. The 
Agency expects manufacturers to demonstrate that emissions will not 
exceed the malfunction thresholds, even with the aftertreatment device 
removed, and then employ the more basic back pressure sensor. This back 
pressure sensor is intended to indicate the presence of the 
aftertreatment device. While the back pressure sensor cannot directly 
detect the performance characteristics of the aftertreatment device, it 
nonetheless provides some level of assurance that emissions are being 
controlled due to the presence of the device. The Agency requests 
comment on the diesel aftertreatment monitoring requirements and data 
on feasibility, and comment on the appropriateness of the diesel 
aftertreatment presence detection requirement. The Agency also requests 
comments and supporting data on the durability of diesel aftertreatment 
devices.
    Note that, for diesel vehicles and engines, the Agency considers 
the EGR system to be the primary emission control system that will be 
used to meet the 2004 standards. This makes the EGR system somewhat 
analogous to the catalyst in an Otto-cycle emission control system. 
Because the Otto-cycle catalyst is responsible for roughly 90 percent 
of emission control, the Agency considers it imperative that the 
catalyst be monitored via OBD to ensure its continued performance. 
Likewise, the diesel EGR system is expected to account for roughly 50 
percent of the emission control, making it perhaps the single largest 
contributor to emission control on a diesel engine. Therefore, the 
Agency considers it imperative that the EGR system be monitored on a 
diesel vehicle or engine. This is especially true given what the Agency 
considers to be a rather low cost associated with today's proposed 
requirement for monitoring this critical emission control 
system.110 The Agency fully expects that manufacturers will 
employ OBD techniques on their diesel EGR systems to ensure 
satisfactory engine performance for their customers. Today's proposal 
simply ensures that the monitoring will occur, and it ensures that the 
monitoring will consider not only engine performance, but also emission 
performance.
---------------------------------------------------------------------------

    \110\ The Agency estimates $3 to $7 per vehicle/engine for 
today's proposed OBD requirements, primarily for development and 
demonstration testing given that most of the diesel monitoring will 
be done by the manufacturer absent any requirement to do so.
---------------------------------------------------------------------------

VII. What Are the Environmental Benefits of This Proposal?

A. 2004 Emission Standards for Heavy-Duty Diesel Engines

    In Chapter 6 of the draft Regulatory Impact Analysis, EPA provides 
a detailed explanation of the methodology used to determine the 
environmental benefits from heavy-duty diesel engines associated with 
this proposal. EPA requests comment on all aspects of the emissions 
inventory analysis. The following discussion gives a general overview 
of the methodology and results.
    In the 1997 rulemaking, EPA's emission inventory modeling assumed 
that all HDDE's which would certify to the future 2004 standards would 
be meeting those standards in-use, under all operating conditions, 
i.e., EPA was not aware of the high NOX emissions being 
emitted by certain HDDE's under certain operating conditions. The 
supplemental standards and testing provisions will help assure that 
assumptions used for the 1997 rulemaking are realized. Therefore, the 
emission inventory modeling discussed below and in the draft RIA for 
today's rule uses the same methodology as the 1997 rule, including the 
same emission factors. For this reason, the emission benefits are 
similar in magnitude to the estimates from the 1997 rulemaking. In 
addition, the emission estimates presented here do not include the 
large, previously unknown, excess emissions from engines manufactured 
from 1988 to 1998.

[[Page 58523]]

    We did not include the excess emissions in the modeling for this 
proposal. While the impact from these previously produced engines would 
affect the total estimate of the emission impact from the in-use fleet 
of HDDE in 2004 and beyond, it would not impact the predicted emission 
benefit resulting from the lowering of the 1998 standard to the 2004 
standards, because the predictions for both standards properly do not 
include these excess emissions. It is this emission reduction which is 
important for this rulemaking. In the future, the Agency will be making 
the necessary changes to future versions of the official EPA mobile 
source emission factor model (currently known as MOBILE 5) to reflect 
the increased NOX emission factors from the engines affected 
by the consent decrees.
    The inventory analysis performed for this proposal builds on the 
inventory analysis associated with the 1997 FRM for heavy-duty diesel 
engines. 111 However, EPA made some modifications to the 
1997 inventory analysis due to recent studies that have been performed 
with the intent of improving the understanding of the emissions impact 
of mobile sources. These modifications included new estimates for 
conversion factors (bhp-hr/mile), scrappage rates, and vehicle miles 
traveled. The Draft RIA discusses the recent studies and their effects 
on the calculated HDDE emissions inventories.
---------------------------------------------------------------------------

    \111\ ``Control of Emissions of Air Pollution from Highway 
Heavy-Duty Engines; Final Rule,'' 62 FR 54694-54730, October 21, 
1997.
---------------------------------------------------------------------------

    To determine total emissions by calendar year, EPA multiplied the 
emission factor times the total vehicle miles traveled (VMT) in that 
year. The emission factors were determined using EPA's emission factor 
model (MOBILE5) for NMHC and NOX with adjustments for the 
new scrappage rates, conversion factors, and VMT distribution. Although 
NMHC and NOX are proposed to be combined as a single 
standard, EPA believes that it is useful to model NMHC and 
NOX separately. Given the technologies that are expected to 
be used on heavy-duty diesel engines to comply with the proposed 
standards, we believe it is reasonable to model the fleet-average 
impact of the proposed standards as being equivalent to a 2.0 g/bhp-hr 
NOX standard and a 0.4 g/bhp-hr NMHC standard.
    Table 13 shows the national projections of total NMHC and 
NOX emissions and the estimated NOX benefits for 
selected years. The emissions are projected to decline over the next 
several years, due to implementation of stricter controls, but then 
begin to increase due to growth in the number of vehicle miles 
traveled, unless there are additional controls. By the year 2015, 
without these additional controls, total national NOX 
emissions are projected to exceed current levels. Figure 5 presents the 
national projections of total NMHC plus NOX with and without 
the proposed engine controls.

                       Table 13.--Estimated National NMHC and NOX Emissions and Proposed Benefits From Heavy-Duty Diesel Vehicles
 
                                                             [Thousand short tons per year]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               NMHC                                             NOx
                          Year                           -----------------------------------------------------------------------------------------------
                                                             Baseline      With controls      Benefit        Baseline      With controls      Benefit
--------------------------------------------------------------------------------------------------------------------------------------------------------
2005....................................................             198             196               3           2,136           1,933             203
2010....................................................             184             174              10           2,191           1,504             686
2015....................................................             197             182              15           2,479           1,433           1,046
2020....................................................             225             205              20           2,900           1,535           1,365
--------------------------------------------------------------------------------------------------------------------------------------------------------


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[[Page 58525]]

    Although this proposal does not require reductions in direct PM 
emissions, the proposed standards are expected to reduce the 
concentrations of secondary PM. Secondary PM is formed when 
NOX reacts with ammonia in the atmosphere to yield ammonium 
nitrate particulate. EPA estimates that the 1.4 million tons per year 
total NOX reduction projected for HDDEs in 2020 would result 
in about a 56,000 tons per year reduction in secondary PM. This 
calculation is described in the Draft RIA, Chapter 6, Section V.B. It 
should be noted that these estimates include a calculation involving 
weighting of the southern California conversion rate by VMT, but the 
Federal standards do not regulate new vehicles sold in California. 
Therefore, these nationwide estimates are somewhat over estimated. We 
intend to address this issue in the final rule.
    The term ``hydrocarbons'' includes many different molecules. 
Speciation of the hydrocarbons would show that many of the molecules 
are those which are considered to be air toxics including benzene, 
formaldehyde, acetaldehyde, and 1,3-butadiene. Hydrocarbons from a HDDE 
include approximately 1.1 percent benzene, 7.8 percent formaldehyde, 
2.9 percent acetaldehyde, and 0.6 percent 1,3-butadiene. Therefore, the 
20,000 tons per year reduction in NMHC projected for 2020 would result 
in about a 2,400 tons per year reduction in air toxics. This is 
discussed in more detail in the Draft RIA.
    EPA also believes the proposed regulations will tend to reduce 
noise. One important source of noise in diesel combustion is the sound 
associated with the combustion event itself. When a premixed charge of 
air and fuel ignites, the very rapid combustion leads to a sharp 
increase in pressure, which is easily heard and recognized as the 
characteristic sound of a diesel engine. The conditions that lead to 
high noise levels also cause high levels of NOX formation. 
Fuel injection changes and other NOX control strategies 
therefore typically reduce engine noise.

B. 2004 Emission Standards for Heavy-Duty Otto-Cycle Vehicles and 
Engines

    In evaluating the environmental impact of the proposed heavy-duty 
gasoline engine and vehicle standards, EPA developed estimates of 
exhaust NOX and NMHC inventories from HDGVs (excluding 
California, Alaska, and Hawaii) both with and without the effect of the 
proposed standards. Full details of the environmental impact analysis 
can be found in Chapter 7 of the draft RIA for today's proposal. The 
following paragraphs summarize the key results. The public is 
encouraged to read the full analysis and to comment on all aspects of 
the work.
    Figure 6 shows the projections of nationwide exhaust 
NMHC+NOx emissions from HDGVs both with and without the 
proposed controls. Table 14 contains the estimated NOx and 
NMHC exhaust emission inventories and reductions due to the proposed 
heavy-duty gasoline engine and vehicle standards. The NOx 
inventory for HDGVs is projected to increase from current levels 
without further controls. With implementation of the proposed 
standards, the exhaust NOx emissions from HDGVs are expected 
to decrease from the baseline by 38 percent by the year 2010 and 61 
percent by the year 2020. Exhaust NMHC emissions are projected to 
decline over the next several years, but then begin to increase 
beginning around 2010. With implementation of the proposed standards, 
the exhaust NMHC emissions from HDGVs are expected to decrease from the 
baseline by 8 percent by the year 2010 and 13 percent by the year 2020.

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[[Page 58526]]



      Table 14.--Estimated NOX and NMHC Inventories and Reductions From the Proposed Exhaust Standards for Heavy-Duty Gasoline Engines and Vehicles
                                                                [Thousand tons per year]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               NMHC                                             NOX
                          Year                           -----------------------------------------------------------------------------------------------
                                                             Baseline     With  controls     Reduction       Baseline     With  controls     Reduction
--------------------------------------------------------------------------------------------------------------------------------------------------------
2005....................................................             236             232               4             329             290              38
2010....................................................             225             208              17             365             223             142
2015....................................................             236             209              27             394             183             212
2020....................................................             255             221              34             432             168             264
--------------------------------------------------------------------------------------------------------------------------------------------------------

    In a similar fashion to that noted for the heavy-duty diesel engine 
standards, the NOX reductions from HDGVs are expected to 
result in reduced secondary PM concentrations. EPA estimates that the 
264,000 tons of NOX reduction in 2020 would result in 
approximately a 10,000 tons per year reduction in secondary PM. This 
calculation is described in the draft RIA, Chapter 6, Section V(B), and 
Chapter 7, Section IV. As noted above, these estimates include a 
calculation involving weighting of the southern California conversion 
rate by VMT, but the Federal standards do not regulate new vehicles 
sold in California. Therefore, these nationwide estimates are somewhat 
over estimated. We intend to address this issue in the final rule.

C. Benefits of the Supplemental Standards and In-Use Control Measures 
of Today's Proposal

    The supplemental standards and in-use control measures of today's 
proposal are expected to play an integral role in achieving the 
emission reductions expected from the 2004 diesel and Otto-cycle 
standards. These measures include the new supplemental standards and 
test procedure requirements for diesel engines, the OBD requirements 
for vehicles and engines below 14,000 lbs GVWR, and the in-use testing 
requirements for Otto-cycle vehicles below 14,000 lbs GVWR.
    These measures are considered vital, as a whole, to assuring that 
the full benefits of the 2004 standards are being achieved. The new 
supplemental standards and test procedure requirements will ensure that 
engines are designed to meet the appropriate standards under a broad 
range of operating conditions. The in-use testing requirements will 
ensure that engines meet the appropriate standards throughout their 
useful lives. Finally, the OBD requirements will help ensure that 
engines in-use continue to operate according to design intent and that 
designs are durable and robust in the field. If vehicles and engines 
malfunction or deteriorate in ways that are not noticed by the driver, 
emissions may be far above the design intent of the engine or vehicle 
for thousands, if not tens of thousands of miles. On-board diagnostic 
systems are uniquely suited to identify such malfunctions. Such 
identification serves to ensure that the engines and vehicles continue 
to operate as designed, thereby ensuring they continue to provide the 
air quality benefits expected by the new standards.
    For example, we expect widespread use of EGR to comply with the 
2004 diesel standards. The emission reduction from the EGR system will 
likely be as high as 50 percent, that is, the engine out emissions will 
be cut in half as a result of the EGR system. Should the EGR system 
malfunction, the emissions could essentially double, and the driver 
would probably not be aware of the malfunction without an OBD 
detection. The same could be true for Otto-cycle vehicles and engines, 
in which case the primary emission control technology will be the 
catalyst, which is responsible for as much as 90 percent of the 
emission control. Should the catalyst deteriorate or fail, emissions 
could increase from 150 percent to 900 percent. 112 Similar 
statements can be made in regards to evaporative leak detection 
monitors. We know that emissions from leaking evaporative systems can 
be very large. In their most recent Staff Report on the OBDII program, 
the California Air Resources Board states that data from current 
evaporative system designs show that leaks approaching a 0.020 inch 
hole begin to rapidly generate excess evaporative emissions (up to 15 
times the standard, which equates to 30 grams per test). 113 
The emissions from a heavy-duty Otto-cycle vehicle, having a fuel tank 
well over 15 gallons, would likely be even higher. Without the OBD 
system, those emissions would probably never be identified and the 
malfunctions would probably never be repaired.
---------------------------------------------------------------------------

    \112\ Assuming a properly operating catalyst conversion 
efficiency of 90 percent, and a deteriorated conversion efficiency 
of anywhere from 75 percent down to 0 percent, which would lead to a 
150 percent to 900 percent emission increase, respectively.
    \113\ Staff Report: Initial Statement of Reasons for 
Rulemaking--Technical Status and Proposed Revisions to Malfunction 
and Diagnostic System Requirements for 1994 and Subsequent Model-
Year Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles and 
Engines (OBD II); October 25, 1996.
---------------------------------------------------------------------------

    Further, the primary goal of OBD is to provide the industry with an 
additional incentive to improve emission control system durability. OBD 
serves that goal by encouraging durable components and systems in order 
to avoid the OBD detection and MIL illumination that will result upon 
their malfunction. Indeed, the light-duty industry has expressed on 
numerous occasions that their primary goal with respect to OBD is to 
avoid MIL illumination because of the adverse way they expect their 
customers to react. 114 Therefore, the presence of the OBD 
system is expected not only to identify malfunctions and deterioration, 
but also to minimize their occurrence.
---------------------------------------------------------------------------

    \114\ Stated more appropriately, their primary goal is to avoid 
MIL illumination while still complying with the OBD requirements.
---------------------------------------------------------------------------

    Benefits such as those described above are not easily quantified, 
but are critical to the success of our program as a whole. Without any 
one of these compliance and in-use control measures, the benefits of 
today's proposal could be diminished.

VIII. What Are the Economic Impacts of the Proposal?

A. 2004 Emission Standards for Heavy-Duty Diesel Engines

1. Expected Technologies
    In assessing the economic impact of the 2004 emission standards 
(including the standards finalized in 1997 and the standards proposed 
today), EPA has used a current best judgement of the combination of 
technologies that an engine manufacturer might use to meet the new 
standards at an acceptable cost. Full details of EPA's cost analysis, 
including information not presented here, can be found in the Draft

[[Page 58527]]

Regulatory Impact Analysis in the public docket. The costs presented 
here were developed assuming that heavy-duty diesel engines would need 
high-flow cooled EGR, combustion chamber optimization, improved 
electronic fuel injection, and variable geometry turbochargers (except 
for light heavy-duty engines). The costs also include testing costs 
necessary to comply with the OBD and not-to-exceed requirements.
    The analysis also assumes that manufacturers would introduce the 
improved electronic fuel injection systems and variable geometry 
turbochargers for some engine models even without the more stringent 
standard in 2004. Both of these technologies will provide significant 
performance benefits both directly, and by allowing manufacturers to 
reduce the use of injection timing retard to comply with the current 
4.0 g/bhp-hr NOX standard. The Agency believes that 
manufacturers may draw similar conclusions for using EGR on some of 
these same engines, however, as a conservative assumption, EPA is 
assuming that no EGR would be used to comply with the current 4.0 g/
bhp-hr NOX standard. For this analysis EPA is also assuming 
that only 50 percent of the costs for the improved electronic fuel 
injection and the use of variable geometry turbochargers are 
attributable to emission control. This is because EPA believes that 
manufacturers would make these improvements for many of their engines, 
even in the absence of these emission standards, to reduce fuel 
consumption and improve engine performance, a similar approach was used 
in the 1997 final rule. The docket for this rulemaking contains 
additional information on this aspect of the Agency's cost analysis, 
including a cost sensitivity analysis regarding the fifty percent 
assumption.115 The Agency requests comment on this approach 
which we intend to revisit in the final rule if appropriate. In 
addition, Chapter 8, Section IV of the draft RIA for this proposal 
contains an estimate of the impact this 50 percent assumption has on 
the HD diesel cost-effectiveness. We recognize this 50 percent 
assumption is not a precise approach to characterizing the costs which 
could otherwise be attributed to our baseline assumptions. However, 
developing a more precise estimate is problematic due to the complexity 
of market demand as well as other uncertainties. Nevertheless, we 
intend to consider developing a more precise estimate of the baseline 
for the final rule analysis. In addition, it may be more appropriate to 
consider performance benefits (improved fuel economy, drive-ability) 
with the other secondary benefits rather than with costs, and we intend 
to reconsider this issue for the final rule. EPA also requests comment 
regarding how the early introduction of these technologies would affect 
compliance costs. EPA also requests comment on whether variable 
geometry turbochargers can serve the function of exhaust braking for 
heavy heavy-duty engines, and what cost savings this would provide for 
manufacturers.
---------------------------------------------------------------------------

    \115\ See EPA Air Docket A-98-32, ``Analysis of Costs and 
Benefits of VGT and Improved Fuel Injection'', EPA Memorandum from 
Charles Moulis.
---------------------------------------------------------------------------

2. Per Engine Costs
    Estimated per engine cost increases are broken into purchase price 
and total life-cycle operating costs. The incremental purchase price 
for new engines is comprised of variable costs (for hardware and 
assembly time) and fixed costs (for R&D, retooling, and certification). 
Total operating costs include expected increases in maintenance. Cost 
estimates based on these projected technology packages represent an 
expected incremental cost of engines in the 2004 model year. Costs in 
subsequent years would be reduced by several factors, as described 
below. Separate projected costs were derived for engines used in three 
service classes of heavy-duty diesel engines. All costs are presented 
in 1995 dollars. Life-cycle costs have been discounted to the year of 
sale.
    The costs of the technologies necessary for meeting the 2004 model 
year standards are itemized in the Draft Regulatory Impact Analysis and 
summarized in Table 8. These estimated costs are higher than those 
estimated for the previous FRM because they include costs for variable 
geometry turbochargers and full use of high-flow cooled EGR, as well as 
small additional costs for the new OBD and compliance testing 
requirements. For light heavy-duty vehicles, the cost of a new 2004 
model year engine is estimated to increase by $428 (compared to the 
previous estimate of $258). For medium heavy duty vehicles the purchase 
price of a new engine is estimated to increase by $593 (compared to the 
previous estimate of $397). Similarly, for heavy heavy-duty engines, 
the initial purchase price is expected to increase by $707 (compared to 
the previous estimate of $406).
    For the long term, EPA has identified various factors that would 
cause cost impacts to decrease over time. First, the analysis 
incorporates the expectation that manufacturers will apply ongoing 
research to making emission controls more effective and less costly 
over time. This expectation is similar to manufacturers' stated goal of 
decreasing their reliance on catalysts to meet emission standards in 
the future. Second, research in the costs of manufacturing has 
consistently shown that as manufacturers gain experience in production, 
they are able to apply innovations to simplify machining and assembly 
operations, use lower cost materials, and reduce the number or 
complexity of component parts. The analysis incorporates the effects of 
this learning curve by projecting that the variable costs of producing 
the low-emitting engines decreases by 20 percent starting with the 
third year of production (2006 model year) and by reducing variable 
costs again by 20 percent starting with the sixth year of production. 
Chapter 4, Section III in the draft RIA for this proposal, as well as 
Chapter V, Section IV of the final RIA for the 1997 final rulemaking 
(see Docket A-95-27, Docket Item 35#V-B-01) contain additional 
discussion of the application of this learning curve. The 2004 HD 
diesel standards will require a fundamental change in technology for 
the engine manufacturers. Considering this change, we believe the 
learning curve concept is appropriate for this rulemaking. The Agency 
requests comments and data regarding the application of this learning 
curve approach to the heavy-duty diesel industry, including information 
regarding any observed reduction in manufacturer costs for the past 
application of similar technology changes for the heavy-duty on-highway 
industry, or other technology changes to the diesel engine industry as 
a whole. We also request comment on the learning curve theory. 
Specifically, we request comment and supporting data regarding the 
theory that manufacturing costs continues to decrease over time, 
possibly ad infinitum, albeit at a slower rate as time progresses.
    Finally, since fixed costs (excluding in-use testing costs) are 
assumed to be recovered over a five-year period, these costs are not 
included in the analysis after the first five model years. Table 15 
lists the projected schedule of costs for each category of vehicle over 
time.

[[Page 58528]]



                           Table 15.--Projected Diesel Engine Cost and Price Increases
                                    [1995 Dollars Discounted to Year of Sale]
----------------------------------------------------------------------------------------------------------------
                                                                                                    Life-cycle
               Vehicle class                              Model year              Purchase price     operating
                                                                                      increase         cost
----------------------------------------------------------------------------------------------------------------
Light heavy-duty...........................  2004...............................            $428              $7
                                             2009 and later.....................             221               7
Medium heavy-duty..........................  2004...............................             593              45
                                             2009 and later.....................             252              45
Heavy heavy-duty...........................  2004...............................             707              96
                                             2009 and later.....................             324              96
----------------------------------------------------------------------------------------------------------------

3. Aggregate Costs to Society
    The above analysis develops per-vehicle cost estimates for each 
vehicle class. Using current data for the size and characteristics of 
the heavy-duty vehicle fleet and making projections for the future, 
these costs can be used to estimate the total cost to the nation for 
the new emission standards in any year. The result of this analysis is 
a projected total cost starting at $424 million (1995 dollars) in 2004. 
Per-vehicle costs savings over time reduce projected costs to a minimum 
value of $223 million in 2009, after which the growth in truck 
population leads to an increase in costs to $285 million in 2020. Total 
costs for these years are presented by vehicle class in Table 16. The 
calculated total costs represent a combined estimate of fixed costs as 
they are allocated over fleet sales, variable costs assessed at the 
point of sale, and operating costs as they are incurred in each 
calendar year. Future sales are projected for years beyond 1995, sales 
are projected to increase each year by a constant value equal to 2 
percent of the number of engines sold in 1995. EPA used a similar 2 
percent growth estimate for the 1997 rulemaking for HD engines, we 
request comment and supporting data which would refine this 
estimate.116 EPA also requests comment and supporting data 
on what impact, if any, costs associated with these new standards might 
have on the sales rate of HD diesel engines in the future. In addition, 
EPA requests comment on whether or not a 2 percent per year increase 
specifically for the light-heavy heavy duty diesel market is an 
appropriate estimate for future growth, considering the recent trend of 
increasing sales of sport-utility vehicles weighing over 8,500 pounds.
---------------------------------------------------------------------------

    \116\ ``Draft Regulatory Impact Analysis: Control of Emissions 
of Air Pollution from Highway Heavy-Duty Engines'', Chapter 7, 
Section II, Available in EPA Air Docket A-95-27, Item # III-B-01

   Table 16.--Estimated Annual Costs for Improved Heavy-Duty Vehicles
                         [Millions of dollars])
------------------------------------------------------------------------
             Category                  2004         2009         2020
------------------------------------------------------------------------
Light heavy-duty.................          142           81           95
Medium heavy-duty................          198           46           59
Heavy heavy-duty.................          185           97          130
                                  --------------------------------------
    Total........................          424          159           97
------------------------------------------------------------------------

B. 2004 Emission Standards for Heavy-Duty Otto-Cycle Vehicles and 
Engines

    This section contains a summary of the Agency's comprehensive 
analyses of the economic impacts of today's proposed regulations for 
heavy-duty Otto-cycle vehicles and engines. The following separate 
factors are analyzed: (1) The technologies expected to be used and 
their projected rates of application; (2) the costs of these technology 
packages incremental to today's vehicle designs (presented on a per-
vehicle basis separately for chassis and engine certified 
configurations) and; (3) the aggregate cost to society of the proposed 
requirements. More information on these analyses can be found in the 
Regulatory Impact Analysis contained in the docket for this rule.
1. Expected Technologies
    The various technologies that could be used to comply with today's 
proposed regulations were previously discussed in the section on 
technological feasibility. In developing costs for the associated 
technologies EPA looked at the current technology used on HDVs and 
compared that to the technology expected to be used to meet the 
proposed regulations. The incremental costs difference was then 
calculated based on the differences between the current (i.e., 
baseline) technology packages and those expected to be used in 2004. 
Table 17 shows both the current baseline and expected technologies for 
complete vehicles. Table 18 shows the current baseline and expected 
technologies for the engine-based standards. These tables only show the 
technologies which are expected to change in some way from their 
current design or be applied to different percentages of the fleet than 
they are currently. Technologies such as sequential multi-port fuel 
injection and EGR, while important to meeting the proposed standards, 
are not expected to be fundamentally changed in their design, or be 
utilized in different percentages of the fleet than they currently are. 
Thus, such technologies are not included in these tables. However, in 
some cases the cost of optimizing such technologies is included in the 
cost estimates.

[[Page 58529]]



               Table 17.--Current and Expected Technology Packages for Complete Vehicle Standards
----------------------------------------------------------------------------------------------------------------
          Technology                     Baseline Federal                          Estimated 2004
----------------------------------------------------------------------------------------------------------------
Catalysts.....................  60% single underfloor               13% single enhanced underfloor.
                                40% dual underfloor                 50% dual enhanced underfloor.
                                                                    37% dual close-coupled and dual enhanced
                                                                     underfloor.
Oxygen sensors................  70% dual heated                     13% dual heated.
                                10% triple heated                   87% quadruple heated.
                                20% quadruple heated
ECM...........................  50% 32 bit computers                100% 32 bit computers.
                                50% 16 bit computers
Adaptive learning.............  0%                                  80%
Individual cylinder A/F         0%                                  10%
 control.
Leak free exhaust.............  90%                                 100%
Insulated exhaust.............  0%                                  40%
Secondary air injection.......  20%                                 30%
ORVR..........................  0%                                  100% A
----------------------------------------------------------------------------------------------------------------
A ORVR is only proposed to apply to complete vehicles 10,000 lbs GVWR and under, and is proposed to be phased in
  over three years, with 100% application to those vehicles in 2006.


                 Table 18.--Current and Expected Technology Packages for Engine-Based Standards
----------------------------------------------------------------------------------------------------------------
          Technology                     Baseline Federal                          Estimated 2004
----------------------------------------------------------------------------------------------------------------
Catalysts.....................  60% single underfloor               13% single enhanced underfloor.
                                40% dual underfloor                 87% dual enhanced underfloor.
Oxygen sensors A..............  70% dual heated                     13% triple heated.
                                10% triple heated                   87% quadruple heated.
                                20% four heated
ECM...........................  50% 32 bit computers                100% 32 bit computers.
                                50% 16 bit computers
Improved fuel control.........  50%                                 100%
Secondary air injection.......  20%                                 50%
----------------------------------------------------------------------------------------------------------------
A The estimated breakdown for 2004 reflects OBD requirements for all HDGEs. However, at this time OBD is only
  proposed to apply to HDGEs under 14,000 lbs GVWR (approximately 60 percent of HDGEs).

2. Per Vehicle Costs
    The costs of the projected technologies presented in the previous 
section are itemized and discussed in detail in the RIA. On a per-
vehicle basis these costs are summarized in Table 14. They are 
presented in two components: purchase price and operating cost. The 
operating costs only apply to ORVR-equipped vehicles and include the 
combined effects of a small fuel economy penalty due to the increased 
weight of the ORVR hardware, and a larger fuel economy benefit 
resulting from the vehicle being able to utilize fuel vapors that would 
otherwise escape to the atmosphere in the absence of ORVR.
    EPA believes that the manufacturers will recover the fixed costs 
associated with research and development, tooling and certification 
over the first five years of production. Thus, these fixed costs are 
not included in the analysis after the first five model years. We 
request comment on whether a five-years amortization period is a 
reasonable estimate. The fixed costs associated with the proposed in-
use testing programs will continue indefinitely. The projected per 
vehicle costs impacts are summarized in Table 19.

                           Table 19.--Projected HDV Price and Operating Cost Increases
----------------------------------------------------------------------------------------------------------------
                                                                                          Purchase     Lifetime
                     Class                                    Model year                   price      operating
                                                                                          increase       cost
----------------------------------------------------------------------------------------------------------------
Complete Vehicles.............................  2004 a................................         $302          -$6
                                                2009 and later........................          297           -6
Engines.......................................  2004 b................................          287
                                                2009 and later........................          248
                                                                                        ...........
----------------------------------------------------------------------------------------------------------------
a This cost includes both ORVR and OBD, which are phased inbeginning with the 2004 model year, but which are not
  proposed to be required on all complete vehicles until the 2006 model year for ORVR and the 2007 model year
  for OBD.
b This cost includes an OBD hardware cost. OBD requirements are phased in beginning with the 2004 model year,
  but are not proposed to be required on all engines under 14,000 lbs GVWR until the 2007 model year.

3. Aggregate Cost to Society
    In addition to the per vehicle costs just described, EPA also 
calculated the aggregate cost to society. This was done by combining 
the per vehicle costs with assumed future sales of HDVs. The results of 
this analysis are summarized in Table 20. The recovery of most fixed 
costs results in slightly reduced costs beginning in 2009, after which 
costs begin to rise in accordance with projected increased sales. The 
aggregate

[[Page 58530]]

costs represent a combined estimate of the fixed costs for research and 
development, tolling and certification as they are allocated over the 
first five years of sales, variable costs assessed at the point of 
sale, and operating costs (primarily in the form of fuel cost savings) 
for ORVR-equipped vehicles (calculated to net present value and applied 
at the point of sale). Future sales are projected for years beyond 
1996, sales are projected to increase each year by a constant value 
equal to 2 percent of the number of engines sold in 1996. EPA used a 
similar 2 percent growth estimate for the 1997 rulemaking for HD 
engines, we request comment and supporting data which would refine this 
estimate. 117 EPA requests comment and supporting data on 
what impact, if any, costs associated with these proposed standards 
might have on the sales rate of HD Otto-cycle engines in the future. We 
also request comment on whether or not a 2 percent per year increase 
specifically for the light-heavy heavy duty Otto-cycle market is an 
appropriate estimate for future growth, considering the recent trend of 
increasing sales of sport-utility vehicles weighing over 8,500 pounds 
GVWR.
---------------------------------------------------------------------------

    \117\ ``Draft Regulatory Impact Analysis: Control of Emissions 
of Air Pollution from Highway Heavy-Duty Engines'', Chapter 7, 
Section II, Available in EPA Air Docket A-95-27, Item # III-B-01.

  Table 20.--Aggregate Cost to Society of the Proposed Heavy-Duty Otto-
                           Cycle Requirements
------------------------------------------------------------------------
                                                               Cost
                          Year                              ($million)
------------------------------------------------------------------------
2004....................................................            $124
2009....................................................             151
2020....................................................             177
------------------------------------------------------------------------

IX. What is the Cost-Effectiveness of the Proposal?

A. 2004 Emission Standards for Heavy-Duty Diesel Engines

    EPA has estimated the per-vehicle cost-effectiveness (i.e., the 
cost per ton of emission reduction) of the model year 2004 
NMHC+NOX standards over the typical lifetime of heavy-duty 
diesel vehicles covered by today's rule. The RIA contains a more 
detailed discussion of the cost-effectiveness analyses. As described 
above in the cost section, the cost of complying with the standards 
will vary by model year. Therefore, the cost-effectiveness will also 
vary from model year to model year. For comparison purposes, the 
discounted costs, emission reductions and cost-effectiveness of the 
standards are shown in Table 21 for the same model years discussed 
above in the cost section. The cost-effectiveness results contained in 
Table 21 present the range in cost-effectiveness resulting from the two 
cost-effectiveness scenarios described above.

  Table 21.--Discounted Per-Vehicle Costs, Emission Reductions and Cost-Effectiveness of the NMHC+NOX Standard
----------------------------------------------------------------------------------------------------------------
                                                                  Discounted lifetime reductions    Discounted
                                                    Discounted                (tons)                   cost-
         Vehicle class             Model year        lifecycle   --------------------------------  effectiveness
                                                       costs            NOX            NMHC           ($/ton)
----------------------------------------------------------------------------------------------------------------
Light Heavy-Duty Diesel         2004............            $435           0.310           0.004           $1380
 vehicles.                      2009 and later..             228                                             725
Medium Heavy-Duty Diesel        2004............             638           0.872           0.012             720
 vehicles.                      2009 and later..             296                                             335
Heavy-Duty Diesel Vehicles....  2004............             803           3.401           0.048             230
                                2009 and later..             420                                             120
Overall (For All Heavy-Duty...  2004............  ..............  ..............  ..............             400
                                2009 and later                                                               200
----------------------------------------------------------------------------------------------------------------

    In addition to the benefits of reducing ozone within and 
transported into urban ozone nonattainment areas, the NOX 
reductions from the new engine standards are expected to have 
beneficial impacts with respect to crop damage, secondary particulate, 
acid deposition, eutrophication, visibility, and forest health. Due to 
the difficulty in accurately quantifying the monetary value of these 
societal benefits, the cost-effectiveness values presented do not 
assign any numerical value to these additional benefits. EPA requests 
comments on all aspects of the cost-effectiveness analysis for heavy-
duty diesel engines.

B. 2004 Emission Standards for Heavy-Duty Otto-Cycle Vehicles and 
Engines

    EPA has estimated the per-vehicle cost-effectiveness (i.e., the 
cost per ton of emission reduction) of the proposed NMHC plus 
NOX emission standards over the lifetime of typical heavy-
duty gasoline vehicles. The RIA contains a more detailed discussion of 
the cost-effectiveness analysis. EPA requests comments on all aspects 
of the cost-effectiveness analysis for heavy-duty gasoline engines and 
vehicles. EPA plans to conduct cost-effectiveness analyses of 
alternatives to the proposed Otto-cycle standards in the final rule 
based on comments received as appropriate.
    As described above, the cost of complying with the proposed 
standards will vary by vehicle category (i.e., a complete Class 2b 
heavy-duty gasoline vehicle, a complete Class 3 heavy-duty gasoline 
vehicle, or an incomplete heavy-duty gasoline vehicle) and model year. 
Therefore, the lifetime cost-effectiveness of the proposed standards 
will vary by model year. For comparison purposes, the discounted 
lifetime costs, emission reductions (in short tons), and cost-
effectiveness of the proposed standards are shown in Table 22 for the 
same model years discussed in the Economic Impact section.

[[Page 58531]]



            Table 22.--Cost-Effectiveness of the Proposed Standards for Heavy-Duty Gasoline Vehicles
----------------------------------------------------------------------------------------------------------------
                                                                                    Discounted
                                                                                     lifetime       Discounted
             HDGV category                 Year of production       Discounted       NMHC+NOX     lifetime cost-
                                                                   lifetime cost     Reduction     effectiveness
                                                                                      (tons)          ($/ton)
----------------------------------------------------------------------------------------------------------------
Class 2B Complete.....................  1.......................            $296       0.56 tons            $530
                                        6 and later.............             291                             520
Class 3 Complete......................  1.......................             296            0.55             530
                                        6 and later.............             291                             520
Incomplete HDGV.......................  1.......................             287            0.61             480
                                        6 and later.............             248                             410
All HDGVs.............................  1.......................             294            0.57             520
                                        6 and later.............             281                             490
----------------------------------------------------------------------------------------------------------------

    EPA has also estimated the cost-effectiveness of the proposed ORVR 
for Class 2B heavy-duty gasoline vehicles. Table 23 contains the 
discounted lifetime cost-effectiveness of the proposed ORVR 
requirements.

  Table 23.--Discounted, Lifetime Cost-Effectiveness of the Proposed ORVR Requirements for Class 2B Heavy-Duty
                                                Gasoline Vehicles
----------------------------------------------------------------------------------------------------------------
                                                                                    Discounted
                                                                                  lifetime  NMHC    Discounted
                       Year of production                           Discounted     NOX  Emission  lifetime cost-
                                                                   lifetime cost    Reductions     effectiveness
                                                                                      (tons)          ($/ton)
----------------------------------------------------------------------------------------------------------------
1...............................................................              $5           0.035            $130
6...............................................................               2           0.035              50
----------------------------------------------------------------------------------------------------------------

    In addition to the benefits of reducing ozone within and 
transported into urban ozone nonattainment areas, the NOX 
emission reductions from the proposed heavy-duty gasoline vehicle and 
engine standards are expected to have beneficial impacts with respect 
to crop damage, secondary particulate, acid deposition, eutrophication, 
visibility, and forest health. The cost-effectiveness values presented 
above do not assign any numerical value to these additional benefits. 
Based on existing studies that have estimated the value of such 
benefits in the past, EPA believes that the actual monetary value of 
the multiple environmental and public health benefits that would be 
produced by the NOX reductions under this proposal will be 
greater than the estimated compliance costs.

X. Are Future Reductions in HD Emissions Possible?

A. Potential Future Standards for Heavy-Duty Diesel Vehicles and 
Engines

1. Possible Future Reductions in Heavy-Duty Diesel NOX and 
NMHC
    As discussed in section II (What is the Environmental Need for this 
Proposal?), heavy-duty vehicles are a major source of national 
NOX emissions and a source of NMHC emissions in the U.S., 
both of which are precursors for tropospheric ozone. Despite the 
important reductions in NOX and NMHC which will occur from 
HD diesel 2004 standards, it is possible that additional reductions in 
NOX and NMHC from heavy-duty diesels will be necessary in 
the future in order for air quality goals to be achieved across the 
country.
    The Agency received written comments from local and state air 
quality agencies and from several environmental organizations in 
response to the 2004 NMHC+NOX proposal in the June 27,1996 
NPRM urging the Agency to finalize more stringent NOX 
standards for the 2004 model year, or to consider standards resulting 
in the largest NOX reduction possible from HD engines. These 
organizations cited future air quality concerns which would require 
additional NOX and NMHC reductions from HD engines and 
vehicles in the future. 116 Though the Agency did not 
finalize more stringent standards, the stakeholders' air quality 
concerns remain.
---------------------------------------------------------------------------

    \116\ See EPA Air Docket A-95-27, Docket Item's IV-D-08, IV-D-
15, and IV-D-16.
---------------------------------------------------------------------------

    The HD SOP signed in July, 1995 included a discussion of future 
research goals for further reductions in NOX and PM from on-
highway HD diesel engines. As described in the SOP, these research 
goals suggested a target value of 1.0 g/bhp-hr NOX. In 
addition, the Agency is aware that the European Union is currently 
considering a range of HD engine NOX levels for potential 
Euro IV emission limits in 2005. At present, the European Union is 
considering Euro IV NOX limits ranging from 1.5 to 2.6 g/
bhp-hr.
    The RIA for this proposal includes a discussion of several 
promising emission control technologies which may offer the potential 
for NOX reductions down to, or even beyond the research 
goals identified in the SOP. These emission control technologies 
include lean NOX adsorption catalysts and urea-based 
selective catalytic reduction systems (SCR). Each of these technologies 
have demonstrated significant NOX reduction capability (up 
to 75 percent and some projections range up to 90 percent). However, 
each technology is still under development, and each has its own set of 
potential difficulties for wide-spread HD application in the U.S. For 
example, current generation NOX adsorber catalysts have been 
shown to be susceptible to fuel sulfur poisoning, and urea-based SCR 
systems would likely require a national distribution system for urea. 
In addition, costs, durability, tamper resistance, and in-use emission 
performance associated with each technology have not been well defined. 
For this reason, EPA does not believe more stringent standards based on 
such

[[Page 58532]]

technology is achievable for the 2004 model year, taking into 
consideration cost, energy, and safety factors. However, such more 
stringent standards may be appropriate in later model years, once these 
technologies are further developed. Furthermore improvement in diesel 
fuel quality, particularly lower sulfur levels, would likely be needed 
to enable these technologies. These issues were the subject of the 
Advance Notice of Proposed Rulemaking on ``Control of Diesel Fuel 
Quality'' that EPA published in May (64 FR 26142, May 13, 1999).
    The Agency requests comment on the need for future reductions in 
NOX and NMHC emissions from HD diesel engines, the time 
frame in which future standards should be considered, and what 
standards should be considered. In addition, the Agency requests 
comment and supporting data, including emission testing data, 
durability data, cost data, and other relevant information, on what 
technologies may be available for meeting more stringent HD diesel 
NOX and/or NMHC levels. The Agency requests comment 
specifically on the feasibility of these advanced aftertreatment 
technologies to attain reductions cited above in the 2007 time frame. 
Finally, the Agency requests comment on what role, if any, diesel fuel 
quality plays in enabling additional reductions from HD diesel engines.
2. Potential Future Reductions in Heavy-Duty Diesel Engine PM
    Section II of this preamble (``What is the Environmental Need for 
this Proposal?''), includes: a discussion of the adverse health 
consequences associated with particulate matter; a discussion of the 
contribution of HD diesel engine PM to national emission inventories; a 
discussion of several recent source apportionment studies for PM; and a 
discussion of the negative health impacts associated specifically with 
diesel exhaust PM, including the potential carcinogenicity of diesel 
PM. The Agency requests comment on whether additional control of HD 
diesel PM beyond the current 0.1g/bhp-hr level may be needed in the 
future to protect the public's health.
    EPA received written comments from several state and local air 
quality agencies as well as several environmental organizations 
regarding the HDDE PM standard in response to the June 27, 1996 NPRM 
for on-highway heavy-duty engines.119 In general, these 
organizations felt that maintaining the current PM standard of 0.1 g/
bhp-hr in model year 2004 was not adequate for protection of human 
health. The commentors stressed the particularly harmful nature of 
diesel PM, and they believed technology was available to justify a 
lower PM standard in 2004.
---------------------------------------------------------------------------

    \119\ See EPA Air Docket A-95-27, Item's IV-D-03, IV-D-08, IV-D-
15, IV-D-19
---------------------------------------------------------------------------

    The HD SOP signed in 1995 included a discussion of a HD diesel PM 
research goal of 0.05 g/bhp-hr. The Agency is also aware that the 
European Union is currently considering a range of PM levels for 
potential Euro IV emission limits for HD diesel in 2005. At present, 
the European Union is considering Euro IV PM limits ranging from 0.015 
to 0.04 g/bhp-hr.
    The RIA for this proposal includes a discussion of the current 
state of the art for HDDE control technologies for both NOX 
and PM control, as well as the technologies the Agency expects 
manufacturers to use to meet the 2004 NMHC+NOX standards. 
The inverse relationship between in-cylinder 120 
NOX and PM emissions is a well documented phenomenon; in-
cylinder modifications which result in lower NOX tend to 
result in an increase in PM. As discussed in the RIA, there are 
technologies available to minimize this inverse relationship, but there 
are limits to what can be done in-cylinder. Data available to date 
indicate the 2004 NMHC+NOX standard and the 0.1g/hp-hr PM 
standard is near the limit of what can be done utilizing only known in-
cylinder technologies (including EGR as an in-cylinder control 
technology). However, a number of promising aftertreatment technologies 
may be available for wide spread HD application which could allow 
manufacturers to meet a PM standard lower than 0.1g/bhp-hr while not 
negatively impacting NOX emissions. As discussed in the RIA, 
these technologies include diesel oxidation catalysts (DOCs) and 
particulate traps. DOCs have the potential to offer modest levels of PM 
control (approximately 10-30 percent), and the level of control is 
dependent on the amount of volatile organic component present in the 
engine's exhaust PM. Particulate traps have the potential to achieve 
large reductions in exhaust PM, approaching 80-90 percent reduction. 
However, dependable regeneration techniques, in-use durability and 
reasonable cost are some of the important issues which still need to be 
addressed. In addition, NOX control technologies such as 
NOX adsorber catalysts and SCR systems could potentially 
allow manufacturers to favor the in-cylinder trade-offs between 
NOX and PM for stringent in-cylinder PM control, and rely on 
aftertreatment to provide NOX control.
---------------------------------------------------------------------------

    \120\ In-cylinder-an engineering term which refers to engine 
design changes which affect emissions in the combustion chamber, as 
compared to aftertreatment device.
---------------------------------------------------------------------------

    As discussed in section IV.B (``Are Changes in Diesel Fuel Quality 
Necessary to Meet the 2004 Standards?''), and in more detail in the RIA 
for this proposal, diesel fuel quality, and in particular, diesel fuel 
sulfur level, can play an important role in enabling certain PM and 
NOX control technologies. Some DOCs and continuously 
regenerable PM traps, as well as current generation lean NOX 
adsorber catalysts can be poisoned by high sulfur levels. Some versions 
of passively regenerated catalyzed traps and DOCs are not poisoned at 
current fuel sulfur levels, but can produce large amounts of sulfate PM 
at current sulfur levels, decreasing their effectiveness. Given this 
information, EPA has not included more stringent PM standards for the 
2004 model year or later in today's proposal. However, the Agency 
requests comment and supporting data on the air quality need, technical 
feasibility, and costs associated with implementing more stringent PM 
standards as early as the 2004 model year. The Agency requests comment 
specifically on the feasibility of the application of PM traps to 
achieve up to 90 percent reductions from today's levels. In addition, 
the Agency requests comment on the range of PM limits currently being 
considered by the European Union, namely 0.015 to 0.04 g/hp-hr. 
Finally, the Agency requests comment on what role, if any, diesel fuel 
quality plays in meeting a more stringent PM standard.
3. Potential Structure of Future Diesel Emission Standards
    EPA regulations for heavy-duty vehicles (i.e., vehicles with a GVWR 
greater than 8500 pounds) have historically been ``fuel-neutral,'' 
meaning that the same standard applied to both gasoline and diesel 
vehicles. Today's proposal moves away from that historical approach 
because we believe there is a case to be made that heavy-duty Otto-
cycle engines may be capable of significantly lower emissions than 
heavy-duty diesel engines given current technology and fuels. In 
addition to proposing tighter standards for heavy-duty Otto-cycle 
engines, however, we have also proposed to change the fundamental 
structure of the compliance program by requiring complete heavy-duty 
Otto-cycle vehicles up to 14,000 pounds GVWR to be certified to 
chassis-based standards, rather than the engine-based standards used 
historically for the entire heavy-duty category. We request comment on

[[Page 58533]]

these changes to the structure of the EPA emission control program for 
heavy-duty vehicles and engines and on the desirability of fuel-neutral 
standards.
    There are several structural options that we are likely to consider 
when we propose future tighter standards for heavy-duty vehicles. 
Having already taken the step of proposing to move complete heavy-duty 
Otto-cycle vehicles up to 14,000 pounds GVWR into a chassis-based 
program with chassis-based standards, we request comment on whether we 
should consider requiring complete diesel vehicles in the same weight 
range to meet chassis-based standards, and if so, what appropriate 
standards might be. Alternatively, the standards could be structured 
such that complete diesel vehicles up to 10,000 pounds GVWR might be 
subject to chassis-based standards, while those between 10,000 and 
14,000 pounds GVWR could be subject to engine-based standards, as they 
are today. We request comment on limiting chassis-based standards to 
diesel vehicles in this manner.
    In addition to the type of standards (vehicle- or engine-based) 
that we might consider in the future for diesel vehicles up to 14,000 
pounds GVWR, another key issue is the level of the standards relative 
to those that apply to Otto-cycle vehicles. This issue is equally 
applicable to heavy-duty vehicles above and below 14,000 pounds GVWR. 
In addition to requesting comment on a chassis-based program for some 
heavy-duty diesel vehicles, we request comment on applying equivalent 
chassis-based standards to diesel and Otto-cycle vehicles, and on the 
role that diesel fuel quality might play in meeting such standards. In 
the context of possible future changes to diesel fuel quality, we 
believe that it may indeed be appropriate and technically feasible to 
require some heavy-duty diesel vehicles up to 14,000 pounds GVWR to be 
subject to the same standards as their Otto-cycle counterparts. In 
addition to the specific issues raised above, we request comment on 
general issues of fuel neutrality and structure of emission standards 
as they might apply to heavy-duty vehicles.

B. Potential Future Standards for Heavy-Duty Otto-Cycle Vehicles

1. Exhaust Emission Standards
    California has adopted a new generation of standards for light-duty 
and medium-duty vehicles, referred to as the LEV-II standards. The new 
California standards for vehicles above 8,500 pounds GVWR are shown in 
Table 24. The light-duty standards are phased in beginning in 2004 
according to an established phase-in schedule. For heavy-duty vehicles, 
there is no set phase-in schedule. California requires that 100 percent 
of HD vehicles comply with the standards shown in Table 24 beginning in 
MY 2007. While the focus of today's notice is on 2004 standards, EPA is 
exploring the appropriateness of adopting standards equivalent to those 
in Table 24 in a future rulemaking. Doing so would allow federal and 
California standards for heavy-duty Otto-cycle vehicles to continue to 
be harmonized beyond the 2007 model year. Thus, today EPA requests 
comment on the feasibility of, cost-effectiveness, and the need for 
standards such as those shown in Table 24, and on the issues noted 
above regarding the fuel-neutrality of future emission standards and 
the possibility of applying equivalent standards to diesel and Otto-
cycle vehicles. In addition, any future rulemaking action would likely 
assess SFTP standards that would apply in conjunction with FTP 
standards. EPA requests comment on the application of SFTP standards to 
heavy-duty Otto-cycle vehicles under 14,000 pounds GVWR.

   Table 24.--California LEV II Full-Life Emission Standards for 2007 and Later Model Year Vehicles over 8,500
                                                   Pounds GVWR
                                                [Grams per mile]
----------------------------------------------------------------------------------------------------------------
                                                                    Nonmethane       Oxides of        Carbon
                 Vehicle weight category (GVWR)                     organic gas      nitrogen        monoxide
----------------------------------------------------------------------------------------------------------------
8,500--10,000 lbs...............................................           0.195             0.2             6.4
10,001--14,000 lbs..............................................           0.23              0.4             7.3
----------------------------------------------------------------------------------------------------------------

2. Evaporative standards
    EPA is not proposing any changes to the Otto-cycle evaporative 
numerical emission standards in today's notice. However, the 1998 
certification results show that, in general, heavy-duty Otto-cycle 
vehicles are meeting the current evaporative standards with a 
substantial safety margin. EPA is concerned that, in the absence of 
more stringent evaporative standards, manufacturers will reduce the 
safety margins they currently use in order to cut costs, resulting in 
rising evaporative emissions. The 1999 certification results appear to 
show this beginning to happen.
    The California Air Resources Board recently proposed and adopted 
new evaporative emission standards applicable to all categories of Otto 
cycle vehicles and engines in the context of the LEV II standards 
discussed in the previous section. Those new evaporative standards call 
for dramatic reductions in the levels of emissions for both the three 
day diurnal plus hot soak and the supplemental two day diurnal plus hot 
soak measurements. In response to CARB's recent LEV II proposal, the 
vehicle manufacturers presented CARB with an alternate proposal for 
revised evaporative emission standards.121 These proposed 
levels, while not as stringent as the standards CARB proposed and 
subsequently adopted, are significantly more stringent than the current 
federal standards. However, most 1998 model year HDVs were certified at 
levels below the manufacturers proposed standards, including 
comfortable safety margins. The current federal standards, CARB's new 
standards, and the manufacturers' proposed standards are all presented 
in the Table 25.
---------------------------------------------------------------------------

    \121\ A copy of the handouts presented to CARB on October 8, 
1998 are in the docket for this rule.

[[Page 58534]]



        Table 25.--``Existing Federal and CARB, and Manufacturer-Proposed Evaporative Emission Standards
----------------------------------------------------------------------------------------------------------------
                                                       Three day diurnal plus hot     Two day diurnal plus hot
                                                              soak (g/test)                 soak (g/test)
----------------------------------------------------------------------------------------------------------------
8,500 lbs 14,000 lbs:
    Current federal standards.......................                           3.0                           3.5
    New CARB standards .............................                           1.0                          1.25
    Manufacturer-proposed standards.................                           1.5                           1.7
GVWR  14,000 lbs:                          ............................  ............................
Current federal standards                                                      4.0                           4.5
New CARB standards A                                                           1.0                          1.25
Manufacturer-proposed standards A                                              1.5                         2.25
----------------------------------------------------------------------------------------------------------------
A Note--These standards would be phased in as a % of sales at a rate of 25, 50, 75, and 100 percent beginning
  with the 2004 model year.

    EPA requests comment whether more stringent evaporative emission 
standards for HDVs may be appropriate, especially considering the 
current certification levels. The Agency also requests comment on our 
belief that the manufacturer-proposed standards are feasible at little 
or no cost. EPA also requests comment on the feasibility and cost of 
other more stringent standards than those proposed by the 
manufacturers, including the standards recently adopted by CARB.

XI. What Are the Opportunities for Public Participation?

A. Comments and the Public Docket

    EPA today opens a formal comment period for this NPRM and will 
accept comments through 30 days after the date of the public hearing. 
The Agency encourages all parties that have an interest in this 
proposal to offer comment on various topics. Of particular interest to 
the Agency are detailed comments in the following areas:
     The technical feasibility, cost-effectiveness, and 
appropriateness under the Clean Air Act of the 2004 NMHC+NOX 
emission standard for heavy-duty diesel engines.
     The feasibility of the 2004 NMHC+NOX standards 
with current diesel fuel, and the specific issue of full useful life 
durability and the impact of sulfuric acid formation on EGR systems.
     The technical feasibility, cost-effectiveness, and 
appropriateness under the Clean Air Act of the proposed 1.0 g/bhp-hr 
NMHC+NOX standard for heavy-duty Otto-cycle engines.
     The appropriateness and design of the proposed ABT program 
for heavy-duty Otto-cycle engines.
     The technical feasibility, cost-effectiveness, and 
appropriateness of the proposed supplemental tests and associated 
emission limits for diesel-cycle heavy-duty engines.
     The technical feasibility, cost-effectiveness, and 
appropriateness of the proposed chassis-based emission standards for 
Otto-cycle heavy-duty vehicles under 14,000 pounds GVWR.
     The proposed ABT program for Otto-cycle heavy-duty 
vehicles under 14,000 pounds GVWR.
     The technical feasibility, cost-effectiveness, and 
appropriateness of the proposed ORVR requirements for complete Otto-
cycle heavy-duty vehicles under 10,000 pounds GVWR.
     The technical feasibility, cost-effectiveness, and 
appropriateness of the proposed OBD requirements for heavy-duty engines 
and vehicles at or below 14,000 lbs GVWR.
     Fuel neutrality of emission standards for diesel and Otto-
cycle heavy-duty vehicles and engines.
    Although the Agency specifically requests comments on the 
identified topics, the Agency welcomes comments on any aspect of the 
proposal. The most useful comments are those supported by appropriate 
and detailed rationales, data, and analyses. The Agency also encourages 
commenters that disagree with elements of the proposal to suggest and 
analyze alternate approaches to meeting the air quality goals of this 
proposal. All comments, with the exception of proprietary information, 
should be directed to the EPA Air Docket Section, Docket No. A-98-32 
before the date specified above. Information related to this rulemaking 
is also found in dockets A-95-27 and A-97-10.
    Commenters who wish to submit proprietary information for 
consideration should clearly separate such information from other 
comments by (1) labeling proprietary information ``Confidential 
Business Information'' and (2) sending proprietary information directly 
to the contact person listed (see FOR FURTHER INFORMATION CONTACT) and 
not to the public docket. This will help ensure that proprietary 
information is not inadvertently placed in the docket. If a commenter 
wants EPA to use a submission of confidential information as part of 
the basis for the final rule, then a non-confidential version of the 
document that summarizes the key data or information should be sent to 
the docket. Any information or data that constitutes, in whole or in 
part, a basis of EPA's regulatory actions will be made public.
    Information covered by a claim of confidentiality will be disclosed 
by EPA only to the extent allowed and in accordance with the procedures 
set forth in 40 CFR part 2. If no claim of confidentiality accompanies 
the submission when it is received by EPA, it will be made available to 
the public without further notice to the commenter.

B. Public Hearing

    The Agency will hold a public hearing as noted in the DATES section 
above. Any person desiring to present testimony at the public hearing 
is asked to notify the contact person listed above at least one week 
prior to the date of the hearing. This notification should include an 
estimate of the time required for the presentation of the testimony and 
any need for audio/visual equipment. EPA suggests that sufficient 
copies of the statement or material to be presented be available to the 
audience. In addition, it is helpful if the contact person receives a 
copy of the testimony or material prior to the hearing.
    The hearing will be conducted informally, and technical rules of 
evidence will not apply. A sign-up sheet will be available at the 
hearing for scheduling the order of testimony. A written transcript of 
the hearing will be prepared. The official record of the hearing will 
be kept open for 30 days after the hearing to allow submittal of 
supplementary information.

XII. What Administrative Requirements Apply to This Proposal?

A. Compliance With Executive Order 12866

    Under Executive Order 12866 (58 FR 51735), the Agency must 
determine whether this regulatory action is ``significant'' and 
therefore subject to review by the Office of Management and

[[Page 58535]]

Budget (OMB) and the requirements of the Executive Order. The Order 
defines a ``significant regulatory action'' as one that is likely to 
result in a rule that may:
    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local, or tribal governments or 
communities;
    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs or the rights and obligations of recipients 
thereof; or
    (4) raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    Pursuant to the terms of Executive Order 12866, EPA has determined 
that this proposed rule is a ``significant regulatory action'' because 
the proposed regulatory provisions, if implemented, would have an 
annual effect on the economy in excess of $100 million. A Regulatory 
Impact Analysis has been prepared and is available in the docket 
associated with this rulemaking. This action was submitted to OMB for 
review as required by Executive Order 12866. Any written comments from 
OMB and any EPA response to OMB comments are in the public docket for 
this rule.

B. Impact on Small Entities

    The Regulatory Flexibility Act (5 U.S.C. 601) requires federal 
agencies to consider potential impacts of federal regulations upon 
small entities. If a preliminary analysis indicates that a regulation 
would have a significant adverse economic impact on a substantial 
number of small entities, then EPA must prepare a regulatory 
flexibility analysis.
    The Agency has determined that this action would not have a 
significant adverse impact on a substantial number of small entities, 
and thus it is not necessary to prepare a regulatory flexibility 
analysis in connection with this rule. Only two small entities are 
known to be affected by this rule. The entities are small businesses 
that certify alternative fuel engines or vehicles, either newly 
manufactured or modified from previously certified gasoline versions. 
EPA contacted these businesses and discussed the proposed rule with 
them, identifying their concerns. The concerns they expressed prompted 
revisions to the proposal, which are addressed elsewhere in the 
preamble. Rule revisions proposed by EPA are intended to minimize 
adverse impacts on the small entities affected by the proposed rule.
    Therefore, as required under section 605 of the Regulatory 
Flexibility Act, 5 U.S.C. 601 et. seq., as amended, I hereby certify 
that this regulation will not have a significant adverse impact on a 
substantial number of small entities.

C. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public 
Law 104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, local, and tribal 
governments and the private sector. Under sections 202 and 205 of the 
UMRA, EPA generally must prepare a written statement to accompany any 
proposed and final rule that includes a federal mandate that may result 
in expenditures by state, local, and tribal governments in the 
aggregate, or by the private sector, of $100 million or more for any 
one year. Before promulgating an EPA rule for which a written statement 
is needed, section 205 of the UMRA generally requires EPA to identify 
and consider a reasonable number of regulatory alternatives and adopt 
the least costly, most cost effective, or least burdensome alternative 
that achieves the objectives of the rule. The provisions of section 205 
do not apply when they are inconsistent with applicable law. Moreover, 
section 205 allows EPA to adopt an alternative other than the least 
costly, most cost effective, or least burdensome alternative if the 
Administrator publishes with the final rule an explanation of why that 
alternative was not adopted. Before EPA establishes any regulatory 
requirements that may significantly or uniquely affect small 
governments, including tribal governments, it must have developed under 
section 203 of the UMRA a small government agency plan. The plan must 
provide for notifying potentially affected small governments, enabling 
officials of affected small governments to have meaningful and timely 
input in the development of EPA regulatory proposals with significant 
federal intergovernmental mandates, and informing, educating, and 
advising small governments on compliance with the regulatory 
requirements.
    Today's proposal contains no Federal mandates (under the regulatory 
provisions of Title II of the UMRA) for State, local, or tribal 
governments. The rule imposes no enforceable duties on any of these 
governmental entities. Nothing in the program would significantly or 
uniquely affect small governments. EPA has determined that this rule 
contains federal mandates that may result in expenditures of $100 
million or more in any one year for the private sector.
    As explained in section III.B of this preamble (``1999 Review of 
Heavy-duty Diesel Engine NMHC+NOX Standards''), the 2004 
heavy-duty diesel standards reaffirmed in this rulemaking were 
established in the Agency's 1997 final rulemaking for heavy-duty 
diesels, and the 1997 rulemaking laid the ground work for this 
proposal. Today's proposal for HD diesel engines is simply a review of 
the appropriateness under the Clean Air Act of the standard finalized 
in 1997, including the need for and technical and economic feasibility 
of the standard based on information available in 1999. Therefore, 
today's proposal does not contain any further analysis of other, 
alternative standards for heavy-duty diesel engines. The reader is 
directed to the rulemaking record for the 1997 rule, contained in EPA 
Air Docket A-95-27, for information on alternatives the Agency 
considered during that rulemaking.
    Today's proposal includes an analysis of an alternative standard 
for HD Otto-cycle engines. Section VI.B of this preamble, and Chapter 
3, Section III(H) of the draft RIA, contain a detailed description of 
the alternative standard proposed by the engine manufacturers. Section 
202(a)(3) of the Clean Air Act requires that EPA must set emission 
standards for heavy-duty engines to reflect the greatest degree of 
emission reduction achievable through the application of technology 
which EPA determines will be available for the model year to which the 
standards apply, giving appropriate consideration to cost, energy, and 
safety factors associated with the application of such technology.
    As indicated above, EPA believes the standards proposed reflect the 
greatest degree of emission reduction achievable by HD Otto-cycle 
engines in the 2004 model year and have a reasonable cost-effectiveness 
level. EPA is requesting comment on the proposed standard and 
alternatives. Based on comments received and information available at 
the time of the final rulemaking, EPA will make a final determination 
under Sec. 202(a)(3) of the CAA. EPA will address the requirements of 
UMRA Sec. 205 in connection with the final rule.

D. Reporting and Recordkeeping Requirements

    The information collection requirements in this proposed rule have 
been submitted for approval to the Office of Management and Budget 
(OMB) under the Paperwork Reduction

[[Page 58536]]

Act, 44 U.S.C. 3501 et seq. An Information Collection Request (ICR) 
document has been prepared by EPA (ICR No. 2060-0104) and a copy may be 
obtained from Sandy Farmer by mail at OPPE Regulatory Information 
Division; U.S. Environmental Protection Agency (2137); 401 M St., S.W.; 
Washington, DC 20460, by email at [email protected], or by 
calling (202) 260-2740. A copy may also be downloaded off the internet 
at
http://www.epa.gov/icr. The following ICR document has been prepared by 
EPA:

------------------------------------------------------------------------
                 EPA ICR #                              Title
------------------------------------------------------------------------
0783.38...................................  Heavy Duty Engine Emission
                                             Certification.
------------------------------------------------------------------------

    The Agency proposes to collect information related to certification 
results. This information will be used to ensure compliance with and 
enforce the provisions in this rule. Responses will be mandatory in 
order to complete the certification process. Section 208(a) of the 
Clean Air Act requires that manufacturers provide information the 
Administrator may reasonably require to determine compliance with the 
regulations; submission of the information is therefore mandatory. EPA 
will consider confidential all information meeting the requirements of 
Sec. 208(c) of the Clean Air Act.
    This collection of information affects an estimated 66 respondents 
with a total of 459 responses per year and a total hour burden of 
65,859 hours, for an estimated 143 hours per response, with estimated 
total annualized costs of $1,599,684 per year. The hours and annual 
cost of information collection activities by a given manufacturer 
depends on manufacturer-specific variables, such as the number of 
engine families, production changes, emissions defects, and so forth. 
Burden means the total time, effort, or financial resources expended by 
persons to generate, maintain, retain, or disclose or provide 
information to or for a Federal agency. This includes the time needed 
to review instructions; develop, acquire, install, and utilize 
technology and systems for the purposes of collecting, validating, and 
verifying information, processing and maintaining information, and 
disclosing and providing information; adjust the existing ways to 
comply with any previously applicable instructions and requirements; 
train personnel to be able to respond to a collection of information; 
search data sources; complete and review the collection of information; 
and transmit or otherwise disclose the information.
    An Agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations are listed in 40 CFR Part 9 and 48 CFR Chapter 15.
    Comments are requested on the Agency's need for this information, 
the accuracy of the provided burden estimates, and any suggested 
methods for minimizing respondent burden, including through the use of 
automated collection techniques. Send comments on the ICR to the 
Director, OPPE Regulatory Information Division; U.S. Environmental 
Protection Agency (2137); 401 M St., S.W.; Washington, DC 20460; and to 
the Office of Information and Regulatory Affairs, Office of Management 
and Budget, 725 17th St., N.W., Washington, DC 20503, marked 
``Attention: Desk Officer for EPA.'' Include the ICR number in any 
correspondence. Since OMB is required to make a decision concerning the 
ICR between 30 and 60 days after October 29, 1999, a comment to OMB is 
best assured of having its full effect if OMB receives it by November 
29, 1999. The final rule will respond to any OMB or public comments on 
the information collection requirements contained in this proposal.

E. Compliance With Executive Order 13045

    Executive Order 13045: ``Protection of Children from Environmental 
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies 
to any rule that: (1) is determined to be ``economically significant'' 
as defined under Executive Order 12866, and (2) concerns an 
environmental health or safety risk that EPA has reason to believe may 
have a disproportionate effect on children. If the regulatory action 
meets both criteria, the Agency must evaluate the environmental health 
or safety effects of the planned rule on children, and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the Agency.
    EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that are based on health or safety risks, such that 
the analysis required under section 5-501 of the Order has the 
potential to influence the regulation. Today's proposal falls into that 
category only in part: risk considerations may be taken into account 
only to the extent the Agency may consider the inherent toxicity of a 
regulated pollutant, and any differential impacts such a pollutant may 
have on children's health, in deciding how to take cost and other 
relevant factors into consideration.
    This rulemaking will achieve important reductions of various 
emissions from heavy-duty trucks, primarily emissions of 
NOX. The rulemaking also addresses NMHC and PM. These 
pollutants raise concerns about a disproportionately greater effect on 
children's health, such as impacts from ozone, PM, and certain toxic 
air pollutants. See section II of this proposal and the RIA for a 
further discussion of these issues. The effects of ozone and PM on 
children's health was addressed in detail in EPA's rulemaking to 
establish these NAAQS, and EPA is not revisiting those issues here. EPA 
also believes the emissions reductions from the proposed strategies 
will reduce air toxics and the related impacts on children's health. 
EPA will be addressing the issues raised by air toxics from motor 
vehicles and their fuels in a separate rulemaking that EPA is 
initiating in the near future under section 202(l)(2) of the Act. That 
rulemaking will address the emissions of hazardous air pollutants from 
motor vehicles and fuels, and the appropriate level of control of 
hazardous air pollutants from these sources.
    In this proposal EPA has evaluated several regulatory strategies 
for reductions in these emissions from heavy-duty engines. For the 
reasons described in this preamble, EPA believes that the strategies 
proposed are preferable under the Clean Air Act to other potentially 
effective and reasonably feasible alternatives considered by the 
Agency, for purposes of reducing emissions from these sources as a way 
of helping areas achieve and maintain the NAAQS for ozone and PM. 
Moreover, consistent with the Clean Air Act, the proposed levels of 
control are designed to achieve the greatest degree of reduction of 
emissions of these pollutants achievable through technology that will 
be available, taking cost and other factors into consideration.

F. Enhancing Intergovernmental Partnerships

    Under Executive Order 12875, EPA may not issue a regulation that is 
not required by statute and that creates a mandate upon a State, local 
or tribal government, unless the Federal government provides the funds 
necessary to pay the direct compliance costs incurred by those 
governments, or EPA consults with those governments. If EPA complies by 
consulting, Executive Order 12875 requires EPA to provide to the Office 
of Management and Budget a description of the extent of EPA's prior

[[Page 58537]]

consultation with representatives of affected State, local and tribal 
governments, the nature of their concerns, copies of any written 
communications from the governments, and a statement supporting the 
need to issue the regulation. In addition, Executive Order 12875 
requires EPA to develop an effective process permitting elected 
officials and other representatives of State, local and tribal 
governments ``to provide meaningful and timely input in the development 
of regulatory proposals containing significant unfunded mandates.''
    Today's rule does not create a mandate on State, local or tribal 
governments. The rule does not impose any enforceable duties on these 
entities. The rule will be implemented at the Federal level and imposes 
compliance obligations only on private industry. Accordingly, the 
requirements of section 1(a) of Executive Order 12875 do not apply to 
this rule.

G. Consultation and Coordination With Indian Tribal Governments

    Under Executive Order 13084, EPA may not issue a regulation that is 
not required by statute, that significantly or uniquely affects the 
communities of Indian tribal governments, and that imposes substantial 
direct compliance costs on those communities, unless the Federal 
government provides the funds necessary to pay the direct compliance 
costs incurred by the tribal governments, or EPA consults with those 
governments. If EPA complies by consulting, Executive Order 13084 
requires EPA to provide to the Office of Management and Budget, in a 
separately identified section of the preamble to the rule, a 
description of the extent of EPA's prior consultation with 
representatives of affected tribal governments, a summary of the nature 
of their concerns, and a statement supporting the need to issue the 
regulation. In addition, Executive Order 13084 requires EPA to develop 
an effective process permitting elected officials and other 
representatives of Indian tribal governments ``to provide meaningful 
and timely input in the development of regulatory policies on matters 
that significantly or uniquely affect their communities.''
    Today's rule does not significantly or uniquely affect the 
communities of Indian tribal governments. The rule will be implemented 
at the Federal level and imposes compliance obligations only on private 
industry. Accordingly, the requirements of section 3(b) of Executive 
Order 13084 do not apply to this rule.

H. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113, section 12(d) (15 U.S.C. 
272 note) directs EPA to use voluntary consensus standards in its 
regulatory activities unless doing so would be inconsistent with 
applicable law or would be otherwise impractical. Voluntary consensus 
standards are technical standards (e.g., materials specifications, test 
methods, sampling procedures, and business practices) that are 
developed or adopted by voluntary consensus standards bodies. NTTAA 
directs EPA to provide Congress, through OMB, explanations when the 
Agency decides not to use available and applicable voluntary consensus 
standards. This rule involves technical standards. The Agency is 
incorporating by reference applicable standards previously finalized by 
the Society of Automotive Engineers and the International Standards 
Organization. For a complete listing of the SAE and ISO standards 
incorporated by reference in this final rule, please see Sec. 86.1, 
``Reference Materials'' in the regulatory language immediately 
following this preamble.

I. Compliance With Executive Order on Federalism

    On August 4, 1999, President Clinton issued a new executive order 
on federalism, Executive Order 13132, which will go into effect on 
November 2, 1999. In the interim, the current Executive Order 12612 on 
federalism is still applicable. Under this order, this rule does not 
have a substantial direct effect upon States, upon the relationship 
between the national government and the States, or upon the 
distribution of power and responsibilities among the various levels of 
government. This rule directly regulates manufacturers of heavy duty 
vehicles and engines, and does not impose any duties or obligations on, 
or restrict the powers of, any state.

XIII. What Is EPA's Statutory Authority for This Proposal?

    Section 202(a)(3) authorizes EPA to establish emission standards 
for heavy duty vehicles and engines.122 These standards are 
to reflect the greatest degree of emission reduction achievable through 
the application of technology which EPA determines will be available 
for the model year to which the standards apply. EPA is to give 
appropriate consideration to cost, energy, and safety factors 
associated with the application of such technology. Section 
202(a)(3)(C) requires that promulgated standards apply for no less than 
three years and go into effect no less than 4 years after promulgation. 
Section 202(m) authorizes regulations requiring installation of on-
board diagnostics systems for light-duty and heavy-duty vehicles and 
engines. Pursuant to sections 202(a)(1) and 202(d), these emission 
standards must be met throughout the entire useful life of the engine 
or vehicle as determined by EPA's regulations. If the Administrator 
determines that a substantial number of vehicles do not conform to 
emission standards when in actual use throughout their useful lives, 
section 207(c) of the Act requires EPA to make a determination of 
nonconformity. Section 208 of the Act requires manufacturers to perform 
tests (where not otherwise reasonably available), make reports and 
provide information the Administrator may reasonably require to 
determine whether the manufacturer is acting in compliance with the Act 
and regulations thereunder. The remainder of section 202, as well as 
sections 203, 206, 207, 208, and 301, provide additional authority for 
promulgation of these regulations.
---------------------------------------------------------------------------

    \122\ U.S.C. 7521(a)(3).
---------------------------------------------------------------------------

List of Subjects

40 CFR Part 85

    Confidential business information, Imports, Incorporation by 
reference, Labeling, Motor vehicle pollution, Reporting and 
recordkeeping requirements, Research, Warranties.

40 CFR Part 86

    Administrative practice and procedure, Confidential business 
information, incorporation by reference, Labeling, Motor vehicle 
pollution, Reporting and recordkeeping requirements.

    Dated: October 6, 1999.
Carol M. Browner,
Administrator.

    For the reasons set forth in the preamble, chapter I, title 40 of 
the Code of Federal Regulations is proposed to be amended as follows:

PART 85--CONTROL OF AIR POLLUTION FROM MOBILE SOURCES

    1. The authority citation for part 85 is revised to read as 
follows:

    Authority: 42 U.S.C. 7521, 7522, 7524, 7525, 7541, 7542, 7543, 
7547, and 7601(a).

[[Page 58538]]

Subpart F--[Amended]

    2. Section 85.501 is revised to read as follows:


Sec. 85.501  General applicability.

    (a) Sections 85.502 through 85.505 are applicable to aftermarket 
conversion systems for which an enforcement exemption is sought from 
the tampering prohibitions contained in section 203 of the Act.
    (b) References in this subpart to engine families and emission 
control systems shall be deemed to apply to durability groups and test 
groups as applicable for manufacturers certifying new light-duty 
vehicles, light-duty trucks, and Otto-cycle complete heavy-duty 
vehicles under the provisions of 40 CFR part 86, subpart S.

Subpart P--[Amended]

    3. Section 85.1501 is amended by revising paragraph (c), to read as 
follows:


Sec. 85.1501  Applicability.

* * * * *
    (c) References in this subpart to engine families and emission 
control systems shall be deemed to apply to durability groups and test 
groups as applicable for manufacturers certifying new light-duty 
vehicles, light-duty trucks, and Otto-cycle complete heavy-duty 
vehicles under the provisions of 40 CFR part 86, subpart S.

Subpart R--[Amended]

    4. Section 85.1701 is amended by revising paragraph (c), to read as 
follows:


Sec. 85.1701  General applicability.

* * * * *
    (c) References in this subpart to engine families and emission 
control systems shall be deemed to apply to durability groups and test 
groups as applicable for manufacturers certifying new light-duty 
vehicles, light-duty trucks, and Otto-cycle complete heavy-duty 
vehicles under the provisions of 40 CFR part 86, subpart S.

PART 86--CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES 
AND ENGINES

    5. The authority citation for part 86 continues to read as follows:

    Authority: 42 U.S.C. 7401-7671q.

    6. Section 86.1 is amended by adding an entry to the table in 
alphanumeric order in paragraphs (b)(2) and (b)(5), to read as follows:


Sec. 86.1  Reference materials.

* * * * *
    (b) * * *
    (2) * * *

------------------------------------------------------------------------
          Document No. and name              40 CFR part 86  reference
------------------------------------------------------------------------
 
*                  *                  *                  *
                  *                  *                  *
SAE J1939, Recommended Practice for a     86.004-17; 86.1806-04
 Serial Control and Communications
 Vehicle Network.
------------------------------------------------------------------------

* * * * *
    (5) * * *

------------------------------------------------------------------------
          Document No. and name              40 CFR part 86  reference
------------------------------------------------------------------------
 
*                  *                  *                  *
                  *                  *                  *
ISO 14230-4 April 1996, Road Vehicles--   86.004-17; 86.1806-04
 Diagnostic systems--KWP 2000
 requirements for Emission-related
 systems.
------------------------------------------------------------------------

Subpart A--[Amended]

    7. A new Sec. 86.000-15 is added to subpart A to read as follows:


Sec. 86.000-15  NOX and particulate averaging, trading, and 
banking for heavy-duty engines.

    Section 86.000-15 includes text that specifies requirements that 
differ from Sec. 86.094-15 or Sec. 86.098-15. Where a paragraph in 
Sec. 86.094-15 or Sec. 86.098-15 is identical and applicable to 
Sec. 86.000-15, this may be indicated by specifying the corresponding 
paragraph and the statement ``[Reserved]. For guidance see Sec. 86.094-
15.'' or ``[Reserved]. For guidance see Sec. 86.098-15.''.
    (a) through (b) [Reserved] For guidance see Sec. 86.094-15.
    (c) [Reserved] For guidance see Sec. 86.098-15.
    (d) through (i) [Reserved] For guidance see Sec. 86.094-15.
    (j) Optional program for early banking for diesel engines. 
Provisions set forth in Secs. 86.094-15 (a), (b), (d) through (i), and 
86.098-15 (c) apply except as specifically stated otherwise in 
Sec. 86.098-15 (j)(1) through (j)(3)(iii).
    (j)(1) through (j)(3)(iii) [Reserved] For guidance see Sec. 86.098-
15.
    (k) Optional program for early banking for Otto-cycle engines. 
Provisions set forth in Secs. 86.094-15(a), (b), (d) through (i), and 
86.098-15(c) apply except as specifically stated otherwise in this 
paragraph (k).
    (1) To be eligible for the optional program described in this 
paragraph (k), the following must apply:
    (i) Credits are generated from Otto-cycle heavy-duty engines.
    (ii) During certification, the manufacturer shall declare its 
intent to include specific engine families in the program described in 
this paragraph. Separate declarations are required for each program and 
no engine families may be included in both programs in the same model 
year.
    (2) Credit generation and use. (i) Credits shall only be generated 
by 2000 and later model year engine families.
    (ii) Credits may only be used for 2004 and later model year heavy-
duty Otto-cycle engines. When used with 2004 and later model year 
engines, NOx credits may be used to meet the NOx 
plus NMHC standard, except as otherwise provided in Sec. 86.004-
11(a)(1)(i)(D).
    (iii) If a manufacturer chooses to use credits generated under this 
paragraph (k) prior to model year 2004, the averaging, trading, and 
banking of such credits shall be governed by the program provided in 
Secs. 86.094-15(a), (b), (d) through (i) and 86.098-15(c) and shall be 
subject to all discounting, credit life limits and all other provisions 
contained therein. In the case where the

[[Page 58539]]

manufacturer can demonstrate that the credits were discounted under the 
program provided in this paragraph (k), that discount may be accounted 
for in the calculation of credits described in Sec. 86.098-15(c).
    (3) Program flexibilities. (i) NOX credits that are 
banked until model year 2004 under this paragraph (k) may be used in 
2004 or any model year thereafter without being forfeited due to credit 
age. The requirement in this paragraph (k)(3) applies instead of the 
requirements in Sec. 86.094-15(f)(2)(i).
    (ii) There are no regional category restraints for averaging, 
trading, and banking of credits generated under the program described 
in this paragraph (k). This applies instead of the regional category 
provisions described in the introductory text of Sec. 86.094-15 (d) and 
(e).
    (iii) Credit discounting. (A) For NOX credits generated 
under this paragraph (k) from engine families with NOX FELs 
greater than 1.0 grams per brake horsepower-hour for oxides of 
nitrogen, a Discount value of 0.9 shall be used instead of 0.8 in the 
credit availability equation in Sec. 86.098-15(c)(1).
    (B) For NOX credits generated under this paragraph (k) 
from engine families with NOX FELs less than or equal to 1.0 
grams per brake horsepower-hour for oxides of nitrogen, a Discount 
value of 1.0 shall be used in place of 0.8 in the credit availability 
equation in Sec. 86.098-15 (c)(1).
    (iv) Credit calculation. For NOX credits generated under 
this paragraph (k), a Std value of 2.0 grams per brake horsepower-hour 
shall be used in place of the current and applicable NOX 
standard in the credit availability equation in Sec. 86.098-15(c)(1).
    (l) Credit apportionment. At the manufacturer's option, credits 
generated under the provisions described in this section may be sold to 
or otherwise provided to another party for use in programs other than 
the averaging, trading and banking program described in this section.
    (1) The manufacturer shall pre-identify two emission levels per 
engine family for the purposes of credit apportionment. One emission 
level shall be the FEL and the other shall be the level of the standard 
that the engine family is required to certify to under Sec. 86.098-10 
or Sec. 86.098-11, as applicable. For each engine family, the 
manufacturer may report engine sales in two categories, ``ABT-only 
credits'' and ``non-manufacturer-owned credits''.
    (i) For engine sales reported as ``ABT-only credits'', the credits 
generated must be used solely in the ABT program described in this 
section.
    (ii) The engine manufacturer may declare a portion of engine sales 
``non-manufacturer-owned credits'' and this portion of the credits 
generated between the standard and the FEL, based on the calculation in 
Sec. 86.098-15(c)(1), would belong to another party. For ABT, the 
manufacturer may not generate any credits for the engine sales reported 
as ``nonmanufacturer-owned credits''. Engines reported as ``non-
manufacturer-owned credits'' shall comply with the FEL and the 
requirements of the ABT program in all other respects.
    (2) Only manufacturer-owned credits reported as ``ABT-only 
credits'' shall be used in the averaging, trading, and banking 
provisions described in this section.
    (3) Credits shall not be double-counted. Credits used in the ABT 
program may not be provided to an engine purchaser for use in another 
program.
    (4) Manufacturers shall determine and state the number of engines 
sold as ``ABT-only credits'' and ``non-manufacturer-owned credits'' in 
the end-of-model year reports required under Sec. 86.098-23.
    8. Section 86.000-16 is amended by removing paragraphs (a) through 
(d) introductory text, adding paragraphs (a), (b), (c), and (d) 
introductory text, and revising paragraph (d)(1), to read as follows:


Sec. 86.000-16  Prohibition of defeat devices.

* * * * *
    (a) No new light-duty vehicle, light-duty truck, heavy-duty 
vehicle, or heavy-duty engine shall be equipped with a defeat device.
    (b) The Administrator may test or require testing on any vehicle or 
engine at a designated location, using driving cycles and conditions 
which may reasonably be expected to be encountered in normal operation 
and use, for the purpose of investigating a potential defeat device.
    (c) [Reserved]. For guidance see Sec. 86.094-16.
    (d) For vehicle and engine designs designated by the Administrator 
to be investigated for possible defeat devices:
    (1) The manufacturer must show to the satisfaction of the 
Administrator that the vehicle or engine design does not incorporate 
strategies that unnecessarily reduce emission control effectiveness 
exhibited during the Federal emissions test procedure when the vehicle 
or engine is operated under conditions which may reasonably be expected 
to be encountered in normal operation and use.
* * * * *
    9. Section 86.001-1 is amended by revising paragraph (b) to read as 
follows:


Sec. 86.001-1  General applicability.

* * * * *
    (b) Optional applicability. (1) A manufacturer may request to 
certify any heavy-duty vehicle of 14,000 pounds Gross Vehicle Weight 
Rating or less in accordance with the light-duty truck provisions 
located in subpart S of this part through the 2003 model year. Heavy-
duty engine or vehicle provisions of this subpart A do not apply to 
such a vehicle.
    (2) Beginning with the 2001 model year, a manufacturer may certify 
any Otto-cycle heavy-duty vehicle of 14,000 pounds Gross Vehicle Weight 
Rating or less in accordance with the provisions for complete Otto-
cycle heavy-duty vehicles located in subpart S of this part for 
purposes of generating credits in the heavy-duty vehicle averaging, 
banking, and trading program contained in Sec. 86.1817-04. Heavy-duty 
engine or heavy-duty vehicle provisions of this subpart A do not apply 
to such a vehicle.
* * * * *
    10. A new Sec. 86.004-1 is added to subpart A to read as follows:


Sec. 86.004-1  General applicability.

    Section 86.004-1 includes text that specifies requirements that 
differ from Sec. 86.001-1. Where a paragraph in Sec. 86.001-1 is 
identical and applicable to Sec. 86.004-1, this may be indicated by 
specifying the corresponding paragraph and the statement ``[Reserved]. 
For guidance see Sec. 86.001-1.''.
    (a) The provisions of this subpart generally apply to 2004 and 
later model year new Otto-cycle heavy-duty engines used in incomplete 
vehicles and vehicles above 14,000 pounds GVWR and new diesel-cycle 
heavy-duty engines. In cases where a provision applies only to a 
certain vehicle group based on its model year, vehicle class, motor 
fuel, engine type, or other distinguishing characteristics, the limited 
applicability is cited in the appropriate section or paragraph. The 
provisions of this subpart continue to generally apply to 2000 and 
earlier model year new Otto-cycle and diesel-cycle light-duty vehicles, 
2000 and earlier model year new Otto-cycle and diesel-cycle light-duty 
trucks, and 2003 and earlier model year new Otto-cycle complete heavy-
duty vehicles at or below 14,000 pounds GVWR. Provisions generally 
applicable to 2001 and later model year new Otto-cycle and diesel-cycle 
light-duty vehicles, 2001 and later model year new Otto-cycle and 
diesel-cycle light-duty trucks, and 2004 and

[[Page 58540]]

later model year Otto-cycle complete heavy-duty vehicles at or below 
14,000 pounds GVWR are located in subpart S of this part.
    (b) Optional applicability. For 2004 and later model years, a 
manufacturer may request to certify any incomplete heavy-duty vehicle 
of 14,000 pounds Gross Vehicle Weight Rating or less in accordance with 
the provisions for complete heavy-duty vehicles located in subpart S of 
this part. Heavy-duty engine or heavy-duty vehicle provisions of this 
subpart A do not apply to such a vehicle.
    (c) [Reserved]
    (d) [Reserved]
    (e) through (f) [Reserved]. For guidance see Sec. 86.001-1.
    11. Section 86.004-2 is amended by adding definitions in 
alphabetical order for ``defeat device,'' ``heavy-duty vehicle,'' and 
``light-duty truck'' to read as follows:


Sec. 86.004-2  Definitions.

* * * * *
    Defeat device means an auxiliary emission control device (AECD) 
that reduces the effectiveness of the emission control system under 
conditions which may reasonably be expected to be encountered in normal 
vehicle operation and use, unless:
    (1) Such conditions are substantially included in the applicable 
Federal emission test procedure for heavy-duty vehicles and heavy-duty 
engines described in subpart N of this part, excluding the test 
procedure referred to as the ``Not-To-Exceed Test Procedure'' contained 
in Sec. 86.1370, and excluding the Maximum Allowable Emission Limits 
contained in Sec. 86.1370(f);
    (2) The need for the AECD is justified in terms of protecting the 
vehicle against damage or accident; or
    (3) The AECD does not go beyond the requirements of engine 
starting.
    Heavy-duty vehicle means any motor vehicle rated at more than 8,500 
pounds GVWR or that has a vehicle curb weight of more than 6,000 pounds 
or that has a basic vehicle frontal area in excess of 45 square feet, 
excluding vehicles with a GVWR greater than 8,500 pounds and less than 
or equal to 10,000 pounds that are defined as light-duty trucks.
    Light-duty truck means: (1) Any motor vehicle rated at 8,500 pounds 
GVWR or less which has a curb weight of 6,000 pounds or less and which 
has a basic vehicle frontal area of 45 square feet or less, which is:
    (i) Designed primarily for purposes of transportation of property 
or is a derivation of such a vehicle; or
    (ii) Designed primarily for transportation of persons and has a 
capacity of more than 12 persons; or
    (iii) Available with special features enabling off-street or off-
highway operation and use; or
    (2) Any motor vehicle rated at greater than 8,500 pounds GVWR and 
less than or equal to 10,000 pounds GVWR which is a complete vehicle 
designed primarily for transportation of persons and has a capacity of 
not more than 12 persons.
* * * * *
    12. A new Sec. 86.004-10 is added to subpart A to read as follows:


Sec. 86.004-10  Emission standards for 2004 and later model year Otto-
cycle heavy-duty engines and vehicles.

    Section 86.004-10 includes text that specifies requirements that 
differ from Sec. 86.099-10. Where a paragraph in Sec. 86.099-10 is 
identical and applicable to Sec. 86.004-10, this may be indicated by 
specifying the corresponding paragraph and the statement ``[Reserved]. 
For guidance see Sec. 86.099-10.''.
    (a)(1) Exhaust emissions from new 2004 and later model year Otto-
cycle HDEs shall not exceed:
    (i)(A) Oxides of Nitrogen plus Non-methane Hydrocarbons (NOX 
+ NMHC) for engines fueled with either gasoline, natural gas, or 
liquefied petroleum gas. 1.0 grams per brake horsepower-hour (0.37 gram 
per megajoule), as measured under transient operating conditions.
    (B) Oxides of Nitrogen plus Non-methane Hydrocarbon Equivalent 
(NOX + NMHCE) for engines fueled with methanol. 1.0 grams 
per brake horsepower-hour (0.37 gram per megajoule), as measured under 
transient operating conditions.
    (C) A manufacturer may elect to include any or all of its Otto-
cycle HDE families in any or all of the emissions ABT programs for 
HDEs, within the restrictions described in Sec. 86.098-15. If the 
manufacturer elects to include engine families in any of these 
programs, the NOX plus NMHC (or NOX plus NMHCE 
for methanol-fueled engines) FELs may not exceed 4.5 grams per brake 
horsepower-hour (1.7 grams per megajoule). This ceiling value applies 
whether credits for the family are derived from averaging, banking, or 
trading programs.
    (ii)(A) Carbon monoxide for engines intended for use in all 
vehicles, except as provided in paragraph (a)(1)(ii)(B) of this 
section. 14.4 grams per brake horsepower-hour (5.36 grams per 
megajoule), as measured under transient operating conditions.
    (B) Carbon monoxide for engines intended for use only in vehicles 
with a Gross Vehicle Weight Rating of greater than 14,000 pounds. 37.1 
grams per brake horsepower-hour (13.8 grams per megajoule), as measured 
under transient operating conditions.
    (C) Idle carbon monoxide. For all Otto-cycle HDEs utilizing 
aftertreatment technology: 0.50 percent of exhaust gas flow at curb 
idle.
    (2) The standards set forth in paragraph (a)(1) of this section 
refer to the exhaust emitted over the operating schedule set forth in 
paragraph (f)(1) of appendix I to this part, and measured and 
calculated in accordance with the procedures set forth in subpart N or 
P of this part.
    (3)(i) A manufacturer may certify one or more Otto-cycle HDE 
configurations intended for use in all vehicles to the emission 
standard set forth in paragraphs (a)(1)(ii)(B) of this section: 
Provided, that the total model year sales of such configuration(s), 
segregated by fuel type, being certified to the emission standard in 
paragraph (a)(1)(ii)(B) of this section represent no more than five 
percent of total model year sales of each fuel type Otto-cycle HDE 
intended for use in vehicles with a Gross Vehicle Weight Rating of up 
to 14,000 pounds by the manufacturer.
    (ii) The configurations certified to the emission standards of 
paragraphs (a)(1) (ii)(B) of this section under the provisions of 
paragraph (a)(3)(i) of this section shall still be required to meet the 
evaporative emission standards set forth in Sec. 86.099-10(b)(1)(i), 
(b)(2)(i) and (b)(3)(i).
    (4) [Reserved]
    (b) [Reserved]. For guidance see Sec. 86.099-10.
    (c) No crankcase emissions shall be discharged into the ambient 
atmosphere from any new 1998 or later model year Otto-cycle HDE.
    (d) Every manufacturer of new motor vehicle engines subject to the 
standards prescribed in this section shall, prior to taking any of the 
actions specified in section 203(a)(1) of the Act, test or cause to be 
tested motor vehicle engines in accordance with applicable procedures 
in subpart N or P of this part to ascertain that such test engines meet 
the requirements of this section.
    13. Section 86.004-11 is amended by adding paragraphs (a)(3) and 
(a)(4) and (b)(1)(iv), and by revising paragraph (b)(2), to read as 
follows:


Sec. 86.004-11  Emission standards for 2004 and later model year diesel 
heavy-duty engines and vehicles.

    (a) * * *
    (3)(i) The weighted average exhaust emissions, as determined under 
Sec. 86.1360-2004(e)(5) pertaining to the supplemental steady-state 
test cycle, for each regulated pollutant shall not exceed 1.0 times the 
applicable

[[Page 58541]]

emission standards or FELs specified in paragraph (a)(1) of this 
section.
    (ii) Exhaust emissions shall not exceed the Maximum Allowable 
Emission Limits (for the corresponding speed and load), as determined 
under Sec. 86.1360-2004(f), when the engine is operated in the steady-
state control area defined under Sec. 86.1360-2004(d).
    (4)(i) The weighted average emissions, as determined under 
Sec. 86.1370 pertaining to the not-to-exceed test procedures, for each 
regulated pollutant shall not exceed 1.25 times the applicable emission 
standards or FELs specified in paragraph (a)(1) of this section, except 
as noted in paragraph (a)(4)(ii) of this section.
     Exhaust emissions shall not exceed either the Maximum Allowable 
Emission Limits (for the corresponding speed and load), as determined 
under Sec. 86.1360(f) or the exhaust emissions specified in paragraph 
(a)(4)(i) of this section, whichever is numerically lower, when the 
engine is operated in the steady-state control area defined under 
Sec. 86.1360(d).
    (b) * * *
    (1) * * *
    (iv) A filter smoke number of 1.0, or the following alternate 
opacity limits:
    (A) A 30 second transient test average opacity limit of 4% for a 5 
inch path; and
    (B) A 10 second steady state test average opacity limit of 4% for a 
5 inch path.
    (2)(i) The standards set forth in paragraphs (b)(1)(i) through 
(iii) of this section refer to exhaust smoke emissions generated under 
the conditions set forth in subpart I of this part and measured and 
calculated in accordance with those procedures.
    (ii) The standards set forth in paragraph (b)(1)(iv) of this 
section refer to exhaust smoke emissions generated under the conditions 
set forth in Sec. 86.1380 and calculated in accordance with the 
procedures set forth in Sec. 86.1372.
* * * * *
    14. Section 86.004-15 is amended by revising the section heading 
and paragraphs (a)(1), (b) introductory text, (b)(1)(i), (b)(1)(ii), 
(c)(1) introductory text, (c)(1)(iii), (d) introductory text, 
(d)(1)(i), (d)(1)(ii), (f) heading, (f)(1)(i), (f)(2)(i), (f)(2)(ii), 
(f)(3)(ii), (f)(3)(iii), (g)(1), (g)(2) introductory text, (g)(2)(i), 
(g)(2)(ii), (g)(4), (j) introductory text, (j)(1) introductory text, 
(k) heading and introductory text, removing paragraphs (a)(2)(iii) and 
(d)(1)(iii), and adding paragraph (l), to read as follows:


Sec. 86.004-15  NOX plus NMHC and particulate averaging, 
trading, and banking for heavy-duty engines.

    (a)(1) Heavy-duty engines eligible for NOX plus NMHC and 
particulate averaging, trading and banking programs are described in 
the applicable emission sandards sections in this subpart. All heavy-
duty engine families which include any engines labeled for use in 
clean-fuel vehicles as specified in 40 CFR part 88 are not eligible for 
these programs. Participation in these programs is voluntary.
* * * * *
    (b) Participation in the NOX plus NMHC and/or 
particulate averaging, trading, and banking programs shall be done as 
follows:
    (1) * * *
    (i) Declare its intent to include specific engine families in the 
averaging, trading and/or banking programs. Separate declarations are 
required for each program and for each pollutant (i.e., NOX 
plus NMHC, and particulate).
    (ii) Declare an FEL for each engine family participating in one or 
more of these two programs.
    (A) The FEL must be to the same level of significant digits as the 
emission standard (one-tenth of a gram per brake horsepower-hour for 
NOX plus NMHC emissions and one-hundredth of a gram per 
brake horsepower-hour for particulate emissions).
    (B) In no case may the FEL exceed the upper limit prescribed in the 
section concerning the applicable heavy-duty engine NOX plus 
NMHC and particulate emission standards.
* * * * *
    (c)(1) For each participating engine family, NOX plus 
NMHC, and particulate emission credits (positive or negative) are to be 
calculated according to one of the following equations and rounded, in 
accordance with ASTM E29-93a, to the nearest one-tenth of a Megagram 
(Mg). Consistent units are to be used throughout the equation.
* * * * *
    (iii) For purposes of the equation in paragraphs (c)(1)(i) and (ii) 
of this section:

Std = the current and applicable heavy-duty engine NOX 
plus NMHC or particulate emission standard in grams per brake 
horsepower hour or grams per Megajoule.
FEL = the NOX plus NMHC, or particulate family emission 
limit for the engine family in grams per brake horsepower hour or 
grams per Megajoule.
CF = a transient cycle conversion factor in BHP-hr/mi or MJ/mi, as 
given in paragraph (c)(2) of this section.
UL = the useful life described in Sec. 86.004-2, or alternative life 
as described in Sec. 86.004-21(f), for the given engine family in 
miles.
Production = the number of engines produced for U.S. sales within 
the given engine family during the model year. Quarterly production 
projections are used for initial certification. Actual production is 
used for end-of-year compliance determination.
Discount = a one-time discount applied to all credits to be banked 
or traded within the model year generated. Except as otherwise 
allowed in paragraphs (k) and (l) of this section, the discount 
applied here is 0.9. Banked credits traded in a subsequent model 
year will not be subject to an additional discount. Banked credits 
used in a subsequent model year's averaging program will not have 
the discount restored.
* * * * *
    (d) Averaging sets for NOX plus NMHC emission credits. 
The averaging and trading of NOX plus NMHC emission credits 
will only be allowed between heavy-duty engine families in the same 
averaging set. The averaging sets for the averaging and trading of 
NOX plus NMHC emission credits for heavy-duty engines are 
defined as follows:
    (1) For NOX+NMHC credits from Otto-cycle heavy-duty 
engines:
    (i) Otto-cycle heavy-duty engines constitute an averaging set. 
Averaging and trading among all Otto-cycle heavy-duty engine families 
is allowed. There are no subclass restrictions.
    (ii) Otto-cycle heavy-duty vehicles certified under the chassis-
based provisions of Subpart S of this Part may not average or trade 
with heavy-duty Otto-cycle engines.
* * * * *
    (f) Banking of NOX plus NMHC, and particulate emission 
credits. (1) * * * (i) NOX plus NMHC, and particulate 
emission credits may be banked from engine families produced in any 
model year.
* * * * *
    (2) * * * (i) NOX plus NMHC and particulate credits 
generated in 2004 and later model years do not expire.
    (ii) Manufacturers withdrawing banked NOX plus NMHC, 
and/or particulate credits shall indicate so during certification and 
in their credit reports, as described in Sec. 86.091-23.
    (3) * * *
    (ii) Banked credits may not be used for NOX plus NMHC or 
particulate averaging and trading to offset emissions that exceed an 
FEL. Banked credits may not be used to remedy an in-use nonconformity 
determined by a Selective Enforcement Audit or by recall testing. 
However, banked credits may be

[[Page 58542]]

used for subsequent production of the engine family if the manufacturer 
elects to recertify to a higher FEL.
    (iii) Banked NOX credits from 2003 and earlier model 
years may be used in place of NOX plus NMHC credits after 
2003 provided that they are used in the correct averaging set and the 
NOX credits have not expired.
    (g)(1) This paragraph (g) assumes NOX plus NMHC, and 
particulate nonconformance penalties (NCPs) will be available for the 
2004 and later model year HDEs.
    (2) Engine families using NOX plus NMHC and/or 
particulate NCPs but not involved in averaging:
    (i) May not generate NOX plus NMHC or particulate 
credits for banking and trading.
    (ii) May not use NOX plus NMHC or particulate credits 
from banking and trading.
* * * * *
    (4) If a manufacturer has any engine family in a given averaging 
set which is using NOX plus NMHC and/or particulate NCPs, 
none of that manufacturer's engine families in that averaging set may 
generate credits for banking and trading.
* * * * *
    (j) Credit apportionment. At the manufacturer's option, credits 
generated under the provisions described in this section may be sold to 
or otherwise provided to another party for use in programs other than 
the averaging, trading and banking program described in this section.
    (1) The manufacturer shall pre-identify two emission levels per 
engine family for the purposes of credit apportionment. One emission 
level shall be the FEL and the other shall be the level of the standard 
that the engine family is required to certify to under Sec. 86.004-10 
or Sec. 86.004-11. For each engine family, the manufacturer may report 
engine sales in two categories, ``ABT-only credits'' and 
``nonmanufacturer-owned credits'.
* * * * *
    (k) Additional flexibility for diesel-cycle engines. If a diesel-
cycle engine family meets the conditions of either paragraph (k)(1) or 
(2) of this section, a Discount of 1.0 may be used in the trading and 
banking calculation, for both NOX plus NMHC and for 
particulate, described in paragraph (c)(1) of this section.
* * * * *
    (l) Additional flexibility for Otto-cycle engines. If an Otto-cycle 
engine family meets the conditions of paragraph (l)(1) or (2) of this 
section, a discount of 1.0 may be used in the trading and banking 
credits calculation for NOX plus NMHC described in paragraph 
(c)(1) of this section.
    (1) The engine family has a FEL of 0.5 g/bhp-hr NOX plus 
NMHC or lower;
    (2) All of the following conditions are met:
    (i) For model years 2004, 2005, and 2006 only;
    (ii) An engine family is certified using carry-over certification 
data from a 2003 or earlier model year where the sum of the 
NOX FEL plus the HC (or hydrocarbon equivalent where 
applicable) certification level is below 1.0 g/bhp-hr.
    15. Section 86.004-16 is added to subpart A to read as follows:


Sec. 86.004-16  Prohibition of defeat devices.

    (a) No new heavy-duty vehicle or heavy-duty engine shall be 
equipped with a defeat device.
    (b) The Administrator may test or require testing on any vehicle or 
engine at a designated location, using driving cycles and conditions 
which may reasonably be expected to be encountered in normal operation 
and use, for the purpose of investigating a potential defeat device.
    (c) [Reserved]
    (d) For vehicle and engine designs designated by the Administrator 
to be investigated for possible defeat devices:
    (1) General. The manufacturer must show to the satisfaction of the 
Administrator that the vehicle or engine design does not incorporate 
strategies that unnecessarily reduce emission control effectiveness 
exhibited during the Federal emissions test procedures, described in 
subpart N of this part, excluding the test procedure referred to as the 
``Not-To-Exceed Test Procedure'' contained in Sec. 86.1370, and the 
Maximum Allowable Emission Limits contained in Sec. 86.1360(f), when 
the vehicle or engine is operated under conditions which may reasonably 
be expected to be encountered in normal operation and use.
    (2) Information submissions required. The manufacturer will provide 
an explanation containing detailed information (including information 
which the Administrator may request to be submitted) regarding test 
programs, engineering evaluations, design specifications, calibrations, 
on-board computer algorithms, and design strategies incorporated for 
operation both during and outside of the Federal emission test 
procedure described in subpart N of this part, excluding the test 
procedure referred to as the ``Not-To-Exceed Test Procedure'' contained 
in Sec. 86.1370.
    16. Section 86.004-17 is added to subpart A, to read as follows:


Sec. 86.004-17  On-board diagnostics.

    (a) General. All heavy-duty engines intended for use in a heavy-
duty vehicle weighing 14,000 pounds GVWR or less must be equipped with 
an on-board diagnostic (OBD) system capable of monitoring all emission-
related engine systems or components during the applicable useful life. 
Heavy-duty engines intended for use in a heavy-duty vehicle weighing 
14,000 pounds GVWR or less must meet the OBD requirements of this 
section according to the phase-in schedule in paragraph (k) of this 
section. All monitored systems and components must be evaluated 
periodically, but no less frequently than once per applicable 
certification test cycle as defined in Appendix I, paragraph (f), of 
this part, or similar trip as approved by the Administrator.
    (b) Malfunction descriptions. The OBD system must detect and 
identify malfunctions in all monitored emission-related engine systems 
or components according to the following malfunction definitions as 
measured and calculated in accordance with test procedures set forth in 
subpart N of this part (engine-based test procedures) excluding the 
test procedure referred to as the ``Not-To-Exceed Test Procedure'' 
contained in Sec. 86.1370, and excluding the test procedure referred to 
as the ``Load Response Test'' contained in Sec. 86.1380.
    (1) Catalysts and particulate traps. (i) Otto-cycle. Catalyst 
deterioration or malfunction before it results in an increase in NMHC 
emissions 1.5 times the NMHC+NOX standard or FEL, as 
compared to the NMHC+NOX emission level measured using a 
representative 4000 mile catalyst system.
    (ii) Diesel. If equipped, catalyst or particulate trap 
deterioration or malfunction before it results in exhaust emissions 
exceeding 1.5 times the applicable standard or FEL for 
NMHC+NOX or PM. This monitoring need not be done if the 
manufacturer can demonstrate that deterioration or malfunction of the 
system will not result in exceedance of the threshold; however, the 
presence of the catalyst or particulate trap must still be monitored.
    (2) Engine Misfire. (i) Otto-cycle. Engine misfire resulting in 
exhaust emissions exceeding 1.5 times the applicable standard or FEL 
for NMHC+NOX or CO; and any misfire capable of damaging the 
catalytic converter.
    (ii) Diesel. Lack of cylinder combustion must be detected.

[[Page 58543]]

    (3) Oxygen sensors. If equipped, oxygen sensor deterioration or 
malfunction resulting in exhaust emissions exceeding 1.5 times the 
applicable standard or FEL for NMHC+NOX or CO.
    (4) Evaporative leaks. If equipped, any vapor leak in the 
evaporative and/or refueling system (excluding the tubing and 
connections between the purge valve and the intake manifold) greater 
than or equal in magnitude to a leak caused by a 0.040 inch diameter 
orifice; an absence of evaporative purge air flow from the complete 
evaporative emission control system. Where fuel tank capacity is 
greater than 25 gallons, the Administrator may, following a request 
from the manufacturer, revise the size of the orifice to the smallest 
orifice feasible, based on test data, if the most reliable monitoring 
method available cannot reliably detect a system leak equal to a 0.040 
inch diameter orifice.
    (5) Other emission control systems. Any deterioration or 
malfunction occurring in an engine system or component directly 
intended to control emissions, including but not necessarily limited 
to, the exhaust gas recirculation (EGR) system, if equipped, the 
secondary air system, if equipped, and the fuel control system, 
singularly resulting in exhaust emissions exceeding 1.5 times the 
applicable emission standard or FEL for NMHC+NOX, CO or 
diesel PM. For engines equipped with a secondary air system, a 
functional check, as described in paragraph (b)(6) of this section, may 
satisfy the requirements of this paragraph (b)(5) provided the 
manufacturer can demonstrate that deterioration of the flow 
distribution system is unlikely. This demonstration is subject to 
Administrator approval and, if the demonstration and associated 
functional check are approved, the diagnostic system must indicate a 
malfunction when some degree of secondary airflow is not detectable in 
the exhaust system during the check. For engines equipped with positive 
crankcase ventilation (PCV), monitoring of the PCV system is not 
necessary provided the manufacturer can demonstrate to the 
Administrator's satisfaction that the PCV system is unlikely to fail.
    (6) Other emission-related engine components. Any other 
deterioration or malfunction occurring in an electronic emission-
related engine system or component not otherwise described above that 
either provides input to or receives commands from the on-board 
computer and has a measurable impact on emissions; monitoring of 
components required by this paragraph (b)(6) must be satisfied by 
employing electrical circuit continuity checks and rationality checks 
for computer input components (input values within manufacturer 
specified ranges based on other available operating parameters), and 
functionality checks for computer output components (proper functional 
response to computer commands) except that the Administrator may waive 
such a rationality or functionality check where the manufacturer has 
demonstrated infeasibility. Malfunctions are defined as a failure of 
the system or component to meet the electrical circuit continuity 
checks or the rationality or functionality checks.
    (7) Performance of OBD functions. Oxygen sensor or any other 
component deterioration or malfunction which renders that sensor or 
component incapable of performing its function as part of the OBD 
system must be detected and identified on vehicles so equipped.
    (c) Malfunction indicator light (MIL). The OBD system must 
incorporate a malfunction indicator light (MIL) readily visible to the 
vehicle operator. When illuminated, the MIL must display ``Check 
Engine,'' ``Service Engine Soon,'' a universally recognizable engine 
symbol, or a similar phrase or symbol approved by the Administrator. 
More than one general purpose malfunction indicator light for emission-
related problems should not be used; separate specific purpose warning 
lights (e.g. brake system, fasten seat belt, oil pressure, etc.) are 
permitted. The use of red for the OBD-related malfunction indicator 
light is prohibited.
    (d) MIL illumination. The MIL must illuminate and remain 
illuminated when any of the conditions specified in paragraph (b) of 
this section are detected and verified, or whenever the engine control 
enters a default or secondary mode of operation considered abnormal for 
the given engine operating conditions. The MIL must blink once per 
second under any period of operation during which engine misfire is 
occurring and catalyst damage is imminent. If such misfire is detected 
again during the following driving cycle (i.e., operation consisting 
of, at a minimum, engine start-up and engine shut-off) or the next 
driving cycle in which similar conditions are encountered, the MIL must 
maintain a steady illumination when the misfire is not occurring and 
then remain illuminated until the MIL extinguishing criteria of this 
section are satisfied. The MIL must also illuminate when the vehicle's 
ignition is in the ``key-on'' position before engine starting or 
cranking and extinguish after engine starting if no malfunction has 
previously been detected. If a fuel system or engine misfire 
malfunction has previously been detected, the MIL may be extinguished 
if the malfunction does not reoccur during three subsequent sequential 
trips during which similar conditions are encountered and no new 
malfunctions have been detected. Similar conditions are defined as 
engine speed within 375 rpm, engine load within 20 percent, and engine 
warm-up status equivalent to that under which the malfunction was first 
detected. If any malfunction other than a fuel system or engine misfire 
malfunction has been detected, the MIL may be extinguished if the 
malfunction does not reoccur during three subsequent sequential trips 
during which the monitoring system responsible for illuminating the MIL 
functions without detecting the malfunction, and no new malfunctions 
have been detected. Upon Administrator approval, statistical MIL 
illumination protocols may be employed, provided they result in 
comparable timeliness in detecting a malfunction and evaluating system 
performance, i.e., three to six driving cycles would be considered 
acceptable.
    (e) Storing of Computer Codes. The OBD system shall record and 
store in computer memory diagnostic trouble codes and diagnostic 
readiness codes indicating the status of the emission control system. 
These codes shall be available through the standardized data link 
connector per specifications as referenced in paragraph (h) of this 
section.
    (1) A diagnostic trouble code must be stored for any detected and 
verified malfunction causing MIL illumination. The stored diagnostic 
trouble code must identify the malfunctioning system or component as 
uniquely as possible. At the manufacturer's discretion, a diagnostic 
trouble code may be stored for conditions not causing MIL illumination. 
Regardless, a separate code should be stored indicating the expected 
MIL illumination status (i.e., MIL commanded ``ON,'' MIL commanded 
``OFF'').
    (2) For a single misfiring cylinder, the diagnostic trouble code(s) 
must uniquely identify the cylinder, unless the manufacturer submits 
data and/or engineering evaluations which adequately demonstrate that 
the misfiring cylinder cannot be reliably identified under certain 
operating conditions. For diesel engines only, the specific cylinder 
for which combustion cannot be detected need not be identified if new 
hardware would be required to do so. The diagnostic trouble

[[Page 58544]]

code must identify multiple misfiring cylinder conditions; under 
multiple misfire conditions, the misfiring cylinders need not be 
uniquely identified if a distinct multiple misfire diagnostic trouble 
code is stored.
    (3) The diagnostic system may erase a diagnostic trouble code if 
the same code is not re-registered in at least 40 engine warm-up 
cycles, and the malfunction indicator light is not illuminated for that 
code.
    (4) Separate status codes, or readiness codes, must be stored in 
computer memory to identify correctly functioning emission control 
systems and those emission control systems which require further engine 
operation to complete proper diagnostic evaluation. A readiness code 
need not be stored for those monitors that can be considered 
continuously operating monitors (e.g., misfire monitor, fuel system 
monitor, etc.). Readiness codes should never be set to ``not ready'' 
status upon key-on or key-off; intentional setting of readiness codes 
to ``not ready'' status via service procedures must apply to all such 
codes, rather than applying to individual codes. Subject to 
Administrator approval, if monitoring is disabled for a multiple number 
of driving cycles (i.e., more than one) due to the continued presence 
of extreme operating conditions (e.g., ambient temperatures below 
40 deg.F, or altitudes above 8000 feet), readiness for the subject 
monitoring system may be set to ``ready'' status without monitoring 
having been completed. Administrator approval shall be based on the 
conditions for monitoring system disablement, and the number of driving 
cycles specified without completion of monitoring before readiness is 
indicated.
    (f) Available diagnostic data. (1) Upon determination of the first 
malfunction of any component or system, ``freeze frame'' engine 
conditions present at the time must be stored in computer memory. 
Should a subsequent fuel system or misfire malfunction occur, any 
previously stored freeze frame conditions must be replaced by the fuel 
system or misfire conditions (whichever occurs first). Stored engine 
conditions must include, but are not limited to: engine speed, open or 
closed loop operation, fuel system commands, coolant temperature, 
calculated load value, fuel pressure, vehicle speed, air flow rate, and 
intake manifold pressure if the information needed to determine these 
conditions is available to the computer. For freeze frame storage, the 
manufacturer must include the most appropriate set of conditions to 
facilitate effective repairs. If the diagnostic trouble code causing 
the conditions to be stored is erased in accordance with paragraph (d) 
of this section, the stored engine conditions may also be erased.
    (2) The following data in addition to the required freeze frame 
information must be made available on demand through the serial port on 
the standardized data link connector, if the information is available 
to the on-board computer or can be determined using information 
available to the on-board computer: Diagnostic trouble codes, engine 
coolant temperature, fuel control system status (closed loop, open 
loop, other), fuel trim, ignition timing advance, intake air 
temperature, manifold air pressure, air flow rate, engine RPM, throttle 
position sensor output value, secondary air status (upstream, 
downstream, or atmosphere), calculated load value, vehicle speed, and 
fuel pressure. The signals must be provided in standard units based on 
SAE specifications incorporated by reference in paragraph (h) of this 
section. Actual signals must be clearly identified separately from 
default value or limp home signals.
    (3) For all OBD systems for which specific on-board evaluation 
tests are conducted (catalyst, oxygen sensor, etc.), the results of the 
most recent test performed by the vehicle, and the limits to which the 
system is compared must be available through the standardized data link 
connector per the appropriate standardized specifications as referenced 
in paragraph (h) of this section.
    (4) Access to the data required to be made available under this 
section shall be unrestricted and shall not require any access codes or 
devices that are only available from the manufacturer.
    (g) Exceptions. The OBD system is not required to evaluate systems 
or components during malfunction conditions if such evaluation would 
result in a risk to safety or failure of systems or components. 
Additionally, the OBD system is not required to evaluate systems or 
components during operation of a power take-off unit such as a dump 
bed, snow plow blade, or aerial bucket, etc.
    (h) Reference materials. The OBD system shall provide for 
standardized access and conform with the following Society of 
Automotive Engineers (SAE) standards and/or the following International 
Standards Organization (ISO) standards. The following documents are 
incorporated by reference (see Sec. 86.1):
    (1) SAE material. Copies of these materials may be obtained from 
the Society of Automotive Engineers, Inc., 400 Commonwealth Drive, 
Warrendale, PA 15096-0001.
    (i) SAE J1850 ``Class B Data Communication Network Interface,'' 
(July 1995) shall be used as the on-board to off-board communications 
protocol. All emission related messages sent to the scan tool over a 
J1850 data link shall use the Cyclic Redundancy Check and the three 
byte header, and shall not use inter-byte separation or checksums.
    (ii) Basic diagnostic data (as specified in Secs. 86.094-17(e) and 
(f)) shall be provided in the format and units in SAE J1979 E/E 
Diagnostic Test Modes,''(July 1996).
    (iii) Diagnostic trouble codes shall be consistent with SAE J2012 
``Recommended Practices for Diagnostic Trouble Code Definitions,'' 
(July 1996).
    (iv) The connection interface between the OBD system and test 
equipment and diagnostic tools shall meet the functional requirements 
of SAE J1962 ``Diagnostic Connector,'' (January 1995).
    (v) As an alternative to the above standards, heavy-duty engines 
may conform to the specifications of SAE J1939 ``Recommended Practice 
for a Serial Control and Communications Vehicle Network.''
    (2) ISO materials. Copies of these materials may be obtained from 
the International Organization for Standardization, Case Postale 56, 
CH-1211 Geneva 20, Switzerland.
    (i) ISO 9141-2 ``Road vehicles--Diagnostic systems--Part 2: CARB 
requirements for interchange of digital information,'' (February 1994) 
may be used as an alternative to SAE J1850 as the on-board to off-board 
communications protocol.
    (ii) ISO 14230-4 ``Road vehicles--Diagnostic systems--KWP 2000 
requirements for Emission-related systems'' may also be used as an 
alternative to SAE J1850.
    (i) Deficiencies and Alternate Fueled Engines. Upon application by 
the manufacturer, the Administrator may accept an OBD system as 
compliant even though specific requirements are not fully met. Such 
compliances without meeting specific requirements, or deficiencies, 
will be granted only if compliance would be infeasible or unreasonable 
considering such factors as, but not limited to: technical feasibility 
of the given monitor and lead time and production cycles including 
phase-in or phase-out of engines or vehicle designs and programmed 
upgrades of computers. Unmet requirements should not be carried over 
from the previous model year except where unreasonable hardware or 
software modifications would be necessary to correct the deficiency, 
and

[[Page 58545]]

the manufacturer has demonstrated an acceptable level of effort toward 
compliance as determined by the Administrator. Furthermore, EPA will 
not accept any deficiency requests that include the complete lack of a 
major diagnostic monitor (``major'' diagnostic monitors being those for 
exhaust aftertreatment devices, oxygen sensor, engine misfire, 
evaporative leaks, and diesel EGR, if equipped), with the possible 
exception of the special provisions for alternate fueled engines. For 
alternate fueled heavy-duty engines (e.g. natural gas, liquefied 
petroleum gas, methanol, ethanol), beginning with the model year for 
which alternate fuel emission standards are applicable and extending 
through the 2006 model year, manufacturers may request the 
Administrator to waive specific monitoring requirements of this section 
for which monitoring may not be reliable with respect to the use of the 
alternate fuel. At a minimum, alternate fuel engines must be equipped 
with an OBD system meeting OBD requirements to the extent feasible as 
approved by the Administrator.
    (j) California OBDII Compliance Option. For heavy-duty engines at 
or below 14,000 pounds GVWR, demonstration of compliance with 
California OBD II requirements (Title 13 California Code Sec. 1968.1), 
as modified pursuant to California Mail Out #97-24 (December 9, 1997), 
shall satisfy the requirements of this section, except that the 
exemption to the catalyst monitoring provisions of California Code Sec. 
1968.1(b)(1.1.2) for diesel engines does not apply, and compliance with 
California Code Secs. 1968.1(b)(4.2.2), pertaining to 0.02 inch 
evaporative leak detection, and 1968.1(d), pertaining to tampering 
protection, are not required to satisfy the requirements of this 
section. Also, the deficiency fine provisions of California Code Secs. 
1968.1(m)(6.1) and (6.2) do not apply.
    (k) Phase-in for Heavy-Duty Engines. Manufacturers of heavy-duty 
engines must comply with the OBD requirements in this section according 
to the following phase-in schedule, based on the percentage of 
projected engine sales within each category:

               OBD Compliance Phase-in Heavy-Duty Engines
[Intended for use in a heavy-duty vehicle weighing 14,000 pounds GVWR or
                                  less]
------------------------------------------------------------------------
                                           Phase-in based on projected
               Model year                             sales
------------------------------------------------------------------------
2004 MY................................  --40% compliance.
                                         --alternative fuel waivers
                                          available.
2005 MY................................  --60% compliance.
                                         --alternative fuel waivers
                                          available.
2006 MY................................  --80% compliance.
                                         --alternative fuel waivers
                                          available.
2007+ MY...............................  --100% compliance.
------------------------------------------------------------------------

    17. Section 86.004-21 is amended by adding paragraphs (m) through 
(p), to read as follows:


Sec. 86.004-21  Application for certification.

* * * * *
    (m) For diesel heavy-duty engines, the manufacturer must provide 
the following additional information pertaining to the supplemental 
steady-state test conducted under Sec. 86.1360-2004:
    (1) Weighted average emissions data, calculated according to 
Sec. 86.1360-2004(e)(5), for all pollutants for which an emission 
standard is established in Sec. 86.004-11(a);
    (2) Brake specific gaseous emission data for each of the 13 test 
points (identified under Sec. 86.1360-2004(b)(1)) and the 3 EPA-
selected test points (identified under Sec. 86.1360-2004(b)(2));
    (3) Concentrations and mass flow rates of all regulated gaseous 
emissions plus carbon dioxide;
    (4) Exhaust smoke opacity (``k'' value);
    (5) Values of all emission-related engine control variables at each 
test point;
    (6) Weighted average particulate matter;
    (7) A statement that the test results correspond to the maximum 
NOX producing condition for a 30 second or longer averaging 
period reasonably expected to be encountered at each test point during 
normal engine operation and use. This statement corresponds to the test 
requirement under Sec. 86.1360-2004(e)(3). The manufacturer also must 
provide a detailed description of all testing, engineering analyses, 
and other information which provides the basis for this statement;
    (8) A statement that the engines will comply with the weighted 
average emissions standard and Maximum Allowable Emission Limits 
specified in Sec. 86.004-11(a)(3) during all normal engine operation 
and use. The manufacturer also must provide a detailed description of 
all testing, engineering analyses, and other information which provides 
the basis for this statement.
    (n) The manufacturer must provide a statement in the application 
for certification that the diesel heavy-duty engine for which 
certification is being requested will comply with the applicable Not-
To-Exceed Limits specified in Sec. 86.004-11(a)(4) when operated under 
all conditions which may reasonably be expected to be encountered in 
normal vehicle operation and use. The manufacturer also must provide a 
detailed description of all testing, engineering analyses, and other 
information which provides the basis for this statement.
    (o) The manufacturer must provide in each application for 
certification of a heavy-duty diesel engine emission test results from 
the Load Response Test conducted according to Sec. 86.1380, including 
at a minimum test results conducted at each of the speeds identified in 
Sec. 86.1380.
    (p) Upon request from EPA, a manufacturer must provide to EPA 
hardware (including scan tools), passwords, and/or documentation 
necessary for EPA to read and interpret (in engineering units if 
applicable) any information broadcast by an engine's on-board computers 
and electronic control modules which relates in anyway to emission 
control devices and auxiliary emission control devices. Passwords 
include any information necessary to enable generic scan tools or 
personal computers access to proprietary emission related information 
broadcast by an engine's on-board computer, if such passwords exist. 
This requirement includes access by EPA to any proprietary code 
information which may be broadcast by an engine's on-board computer and 
electronic control modules. Information which is confidential business 
information must be marked as such. Engineering units refers to the 
ability to read and interpret information in commonly understood 
engineering units, for example, engine speed in revolutions per minute 
or per second, injection timing parameters such as start of injection 
in degree's before top-dead center, fueling rates in cubic centimeters 
per stroke, vehicle speed in milers per hour or per kilometer.
    18. Section 86.004-30 is amended by revising paragraph (f), to read 
as follows:


Sec. 86.004-30  Certification.

* * * * *

[[Page 58546]]

    (f) For engine families required to have an OBD system, 
certification will not be granted if, for any test vehicle approved by 
the Administrator in consultation with the manufacturer, the 
malfunction indicator light does not illuminate under any of the 
following circumstances, unless the manufacturer can demonstrate that 
any identified OBD problems discovered during the Administrator's 
evaluation will be corrected on production vehicles.
    (1)(i) Otto-cycle. A catalyst is replaced with a deteriorated or 
defective catalyst, or an electronic simulation of such, resulting in 
an increase of 1.5 times the NMHC+NOX standard or FEL above 
the NMHC+NOX emission level measured using a representative 
4000 mile catalyst system.
    (ii) Diesel. If monitored for emissions performance--a catalyst or 
particulate trap is replaced with a deteriorated or defective catalyst 
or trap, or an electronic simulation of such, resulting in exhaust 
emissions exceeding 1.5 times the applicable standard or FEL for 
NMHC+NOX or PM. If not monitored for emissions performance--
removal of the catalyst or particulate trap is not detected and 
identified.
    (2)(i) Otto-cycle. An engine misfire condition is induced resulting 
in exhaust emissions exceeding 1.5 times the applicable standards or 
FEL for NMHC+NOX or CO.
    (ii) Diesel. An engine misfire condition is induced and is not 
detected.
    (3) If so equipped, any oxygen sensor is replaced with a 
deteriorated or defective oxygen sensor, or an electronic simulation of 
such, resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC+NOX or CO.
    (4) If so equipped, a vapor leak is introduced in the evaporative 
and/or refueling system (excluding the tubing and connections between 
the purge valve and the intake manifold) greater than or equal in 
magnitude to a leak caused by a 0.040 inch diameter orifice, or the 
evaporative purge air flow is blocked or otherwise eliminated from the 
complete evaporative emission control system.
    (5) A malfunction condition is induced in any emission-related 
engine system or component, including but not necessarily limited to, 
the exhaust gas recirculation (EGR) system, if equipped, the secondary 
air system, if equipped, and the fuel control system, singularly 
resulting in exhaust emissions exceeding 1.5 times the applicable 
emission standard or FEL for NMHC+NOX, CO or PM.
    (6) A malfunction condition is induced in an electronic emission-
related engine system or component not otherwise described above that 
either provides input to or receives commands from the on-board 
computer resulting in a measurable impact on emissions.
    20. Subpart B is amended by revising the heading of the subpart, to 
read as follows:

Subpart B--Emission Regulations for 1977 and Later Model Year New 
Light-Duty Vehicles and New Light-Duty Trucks and New Otto-Cycle 
Complete Heavy-Duty Vehicles; Test Procedures

    21. Section 86.101 is amended by revising paragraphs (a) 
introductory text and (d), and by adding paragraph (e) to read as 
follows:


Sec. 86.101  General applicability.

    (a) The provisions of this subpart are applicable to 1997 and later 
model year new light-duty vehicles and light duty trucks, and 2004 and 
later model year new Otto-cycle complete heavy-duty vehicles.
* * * * *
    (d) References in this subpart to engine families and emission 
control systems shall be deemed to apply to durability groups and test 
groups as applicable for manufacturers certifying new light-duty 
vehicles, light-duty trucks, and Otto-cycle complete heavy-duty 
vehicles under the provisions of Subpart S of this part.
    (e) References in this subpart to light-duty vehicles or light-duty 
trucks shall be deemed to apply to light-duty vehicles, light-duty 
trucks, or Otto-cycle complete heavy-duty vehicles as applicable for 
manufacturers certifying new light-duty vehicles, light-duty trucks, 
and Otto-cycle complete heavy-duty vehicles under the provisions of 
Subpart S of this part.
    22. Section 86.129-94 is amended by revising paragraph (a) to read 
as follows:


Sec. 86.129-94  Road load power, test weight, inertia weight class 
determination, and fuel temperature profile.

* * * * *
    (a) Flywheels, electrical, or other means of simulating test weight 
as shown in the following table shall be used. If the equivalent test 
weight specified is not available on the dynamometer being used, the 
next higher equivalent test weight (not to exceed 250 pounds) available 
shall be used:

------------------------------------------------------------------------
                                            Equivalent
          Test weight basis 4,5             test weight   Inertia weight
                                             (pounds)     class (pounds)
------------------------------------------------------------------------
         Road load power at 50 mi/hour--light-duty trucks 1,2,3
------------------------------------------------------------------------
Up to 1062..............................           1,000           1,000
1063 to 1187............................           1,125           1,000
1188 to 1312............................           1,250           1,250
1313 to 1437............................           1,375           1,250
1438 to 1562............................           1,500           1,500
1563 to 1687............................           1,625           1,500
1688 to 1812............................           1,750           1,750
1813 to 1937............................           1,875           1,750
1938 to 2062............................           2,000           2,000
2063 to 2187............................           2,125           2,000
2188 to 2312............................           2,250           2,250
2313 to 2437............................           2,375           2,250
2438 to 2562............................           2,500           2,500
2563 to 2687............................           2,625           2,500
2688 to 2812............................           2,750           2,750
2813 to 2937............................           2,875           2,750
2938 to 3062............................           3,000           3,000
3063 to 3187............................           3,125           3,000
3188 to 3312............................           3,250           3,000
3313 to 3437............................           3,375           3,500

[[Page 58547]]

 
3438 to 3562............................           3,500           3,500
3563 to 3687............................           3,625           3,500
3688 to 3812............................           3,750           3,500
3813 to 3937............................           3,875           4,000
3938 to 4125............................           4,000           4,000
4126 to 4375............................           4,250           4,000
4376 to 4625............................           4,500           4,500
4626 to 4875............................           4,750           4,500
4876 to 5125............................           5,000           5,000
5126 to 5375............................           5,250           5,000
5376 to 5750............................           5,500           5,500
5751 to 6250............................           6,000           6,000
6251 to 6750............................           6,500           6,500
6751 to 7250............................           7,000           7,000
7251 to 7750............................           7,500           7,500
7751 to 8250............................           8,000           8,000
8251 to 8750............................           8,500           8,500
8751 to 9250............................           9,000           9,000
9251 to 9750............................           9,500           9,500
9751 to 10250...........................          10,000          10,000
10251 to 10750..........................          10,500          10,500
10751 to 11250..........................          11,000          11,000
11251 to 11750..........................          11,500          11,500
11751 to 12250..........................          12,000          12,000
12251 to 12750..........................          12,500          12,500
12751 to 13250..........................          13,000          13,000
13251 to 13750..........................          13,500          13,500
13751 to 14000..........................          14,000         14,000
------------------------------------------------------------------------
\1\ For all light-duty trucks except vans, and for heavy-duty vehicles
  optionally certified as light-duty trucks, and for complete heavy-duty
  vehicles, the road load power (horsepower) at 50 mi/h shall be 0.58
  times B (defined in footnote 3 of this table) rounded to the nearest
  \1/2\ horsepower.
\2\ For vans, the road load power at 50 mi/h (horsepower) shall be 0.50
  times B (defined in footnote 3 of this table) rounded to the nearest
  \1/2\ horsepower.
\3\ B is the basic vehicle frontal area (square foot) plus the
  additional frontal area (square foot) of mirrors and optional
  equipment exceeding 0.1 ft2 which are anticipated to be sold on more
  than 33 percent of the car line. Frontal area measurements shall be
  computed to the nearest 10th of a square foot using a method approved
  in advance by the Administrator.
\4\ For model year 1994 and later heavy light-duty trucks not subject to
  the Tier 0 standards of Sec.  86.094-9, test weight basis is as
  follows: for emissions tests, the basis shall be adjusted loaded
  vehicle weight, as defined in Sec.  86.094-2; and for fuel economy
  tests, the basis shall be loaded vehicle weight, as defined in Sec.
  86.082-2, or, at the manufacturer's option, adjusted loaded vehicle
  weight as defined in Sec.  86.094-2. For all other vehicles, test
  weight basis shall be loaded vehicle weight, as defined in Sec.
  86.082-2.
\5\ Light-duty vehicles over 5,750 lb. loaded vehicle weight shall be
  tested at a 5,500 lb. equivalent test weight.

* * * * *

Subpart H--[Amended]

    23. Section 86.701-94 is revised to read as follows:


Sec. 86.701-94  General applicability.

    (a) The provisions of this subpart apply to: 1994 and later model 
year Otto-cycle and diesel light-duty vehicles; 1994 and later model 
year Otto-cycle and diesel light-duty trucks; and 1994 and later model 
year Otto-cycle and diesel heavy-duty engines; and 2004 and later model 
year Otto-cycle complete heavy-duty vehicles. The provisions of subpart 
B of this part apply to this subpart.
    (b) References in this subpart to engine families and emission 
control systems shall be deemed to apply to durability groups and test 
groups as applicable for manufacturers certifying new light-duty 
vehicles, light-duty trucks, and Otto-cycle complete heavy-duty 
vehicles under the provisions of subpart S of this part.

Subpart K--[Amended]

    24. Section 86.1001-84 is amended by revising paragraph (b), to 
read as follows:


Sec. 86.1001-84  Applicability.

* * * * *
    (b) References in this subpart to engine families and emission 
control systems shall be deemed to apply to durability groups and test 
groups as applicable for manufacturers certifying new light-duty 
vehicles, light-duty trucks, and Otto-cycle complete heavy-duty 
vehicles under the provisions of subpart S of this part.

Subpart L--[Amended]

    25. Section 86.1101-87 is revised to read as follows:


Sec. 86.1101-87  Applicability.

    (a) The provisions of this subpart are applicable for 1987 and 
later model year gasoline-fueled and diesel heavy-duty engines and 
heavy-duty vehicles. These vehicles include light-duty trucks rated in 
excess of 6,000 pounds gross vehicle weight.
    (b) References in this subpart to engine families and emission 
control systems shall be deemed to apply to durability groups and test 
groups as applicable for manufacturers certifying new light-duty trucks 
and Otto-cycle complete heavy-duty vehicles under the provisions of 
subpart S of this part.

Subpart N--[Amended]

    26. Section 86.1304-90 is revised to read as follows:


Sec. 86.1304-90  Section numbering; construction.

    (a) Section numbering. The model year of initial applicability is 
indicated by the section number. The two digits following the hyphen 
designate the first model year for which a section is applicable. The 
section continues to apply to subsequent model years unless a later 
model year section is adopted.

    Example: Section 86.18xx-01 applies to the 2001 and subsequent 
model years. If a

[[Page 58548]]

Sec. 86.18xx-03 is promulgated it would apply beginning with the 
2003 model year; Sec. 86.18xx-01 would apply to model years 2001 
through 2002.

    (b) A section reference without a model year suffix refers to the 
section applicable for the appropriate model year.
    27. A new Sec. 86.1305-2004 is added to subpart N, to read as 
follows:


Sec. 86.1305-2004  Introduction; structure of subpart.

    (a) This subpart describes the equipment required and the 
procedures to follow in order to perform exhaust emissions test on 
Otto-cycle and diesel heavy duty engines. Subpart A of this part sets 
forth the emission standards and general testing requirements to comply 
with EPA certification procedures.
    (b) This subpart contains five key sets of requirements, as 
follows: specifications and equipment needs (Secs. 86.1306 through 
86.1314); calibration methods and frequencies (Secs. 86.1316 through 
86.1326); test procedures (Secs. 86.1327 through 86.1341 and 
Secs. 86.1360 through 86.1380); calculation formulas (Secs. 86.1342 and 
86.1343); and data requirements (Sec. 86.1344).
    29. A new Sec. 86.1360-2004 is added to subpart N to read as 
follows:


Sec. 86.1360-2004  Supplemental steady-state test; test cycle and 
procedures.

    (a) Applicability. This section applies to diesel heavy duty 
engines.
    (b) Test cycle. (1) The following 13-mode cycle must be followed in 
dynamometer operation on the test engine:

----------------------------------------------------------------------------------------------------------------
                                                                             Percent     Weighting   Mode length
                  Mode No.                           Engine speed              load        factor      (minutes)
----------------------------------------------------------------------------------------------------------------
1..........................................  Idle                          ...........         0.15            4
2..........................................  A                                     100         0.08            2
3..........................................  B                                      50         0.10            2
4..........................................  B                                      75         0.10            2
5..........................................  A                                      50         0.05            2
6..........................................  A                                      75         0.05            2
7..........................................  A                                      25         0.05            2
8..........................................  B                                     100         0.09            2
9..........................................  B                                      25         0.10            2
10.........................................  C                                     100         0.08            2
11.........................................  C                                      25         0.05            2
12.........................................  C                                      75         0.05            2
13.........................................  C                                      50         0.05            2
----------------------------------------------------------------------------------------------------------------

    (2) In addition to the 13 test points identified in paragraph 
(b)(1) of this section, EPA may select, and require the manufacturer to 
conduct the test using, up to 3 additional test points within the 
control area (as defined in paragraph (d) of this section). EPA will 
notify the manufacturer of these supplemental test points in writing in 
a timely manner before the test.
    (c) Determining Engine Speeds. (1) The engine speeds A, B and C, 
referenced in the table in paragraph (b)(1) of this section, and speeds 
D and E, referenced in Sec. 86.1380, must be determined as follows:

Speed A = nlo + 25% (nhi-nlo)
Speed B = nlo+ 50% (nhi-nlo)
Speed C = nlo + 75% (nhi-nlo)
Speed D = nlo + 100% (nhi-nlo)
Speed E = nlo + 15% (nhi-nlo)

Where:

nhi = High speed as determined by calculating 70% of the 
maximum power. The highest engine speed where this power value occurs 
on the power curve is defined as nhi.
nlo = Low speed as determined by calculating 50% of the 
maximum power. The lowest engine speed where this power value occurs on 
the power curve is defined as nlo.
Maximum power = the maximum observed power calculated from the torque/
speed ratios determined according to the engine mapping procedures 
defined in Sec. 86.1332. Power = (speed  x  torque)/5252, where speed 
is in revolutions per minute and torque is in foot-pounds.

    (2) If the measured engine speeds A, B, and C are within 3 % of the 
engine speeds as declared by the manufacturer, the declared engine 
speeds shall be used for the emissions test. If the tolerance is 
exceeded for any of the engine speeds, the measured engine speeds shall 
be used for the emissions test.
    (d) Determining the control area. The control area is the area 
between the engine speeds A and C, as defined in paragraph (c) of this 
section, and between 25 to 100 percent load.
    (e) Test requirements. (1) Engine warm-up. Prior to beginning the 
test sequence, the engine must be warmed-up according to the procedures 
in Sec. 86.1332-90(d)(3).
    (2) Test sequence. The test must be performed in the order of the 
mode numbers in paragraph (b)(1) of this section. The EPA-selected test 
points identified under paragraph (b)(2) of this section must be 
performed immediately upon completion of mode 13. The engine must be 
operated for the prescribed time in each mode, completing engine speed 
and load changes in the first 20 seconds of each mode. The specified 
speed must be held to within 50 rpm and the specified 
torque must be held to within 2 percent of the maximum 
torque at the test speed.
    (3) The test must be conducted with all emission-related engine 
control variables in the highest brake-specific NOX 
emissions state which could be encountered for a 30 second or longer 
averaging period at the given test point.
    (4) Exhaust emissions measurements and calculations. (i) 
Manufacturers must follow the exhaust emissions sample analysis 
procedures under Sec. 86.1340, and the calculation formulas and 
procedures under Sec. 86.1342, for the 13-mode cycle and the 3 EPA-
selected test points.
    (ii) Prior to starting the measurements for the EPA-selected test 
points, the engine must be conditioned at mode 13 for a period of three 
minutes.
    (5) Calculating the weighted average emissions. For each regulated 
gaseous pollutant, the weighted average emissions must be calculated as 
follows:
[GRAPHIC] [TIFF OMITTED] TP29OC99.005

Where:

AWA = Weighted average emissions for each regulated gaseous 
pollutant, in grams per brake horse-power hour.
AWM = Weighted mass emissions level, in grams per brake 
horse-power hour, as defined in Sec. 86.1342.

[[Page 58549]]

WF = Weighting factor corresponding to each mode of the 
steady-state test cycle, as defined in paragraph (b)(1) of this 
section.
i = The modes of the steady-state test cycle, as defined in paragraph 
(b)(1) of this section.
n = 13, corresponding to the 13 modes of the steady-state test cycle, 
as defined in paragraph (b)(1) of this section.

    (f) Maximum Allowable Emission Limits. (1) For gaseous emissions, 
the 12 non-idle test point results and the four-point linear 
interpolation procedure specified in paragraph (g) of this section for 
intermediate conditions, shall define Maximum Allowable Emission Limits 
for purposes of Sec. 86.004-11(a)(3). The control area extends from the 
25% to the 75% engine speeds, at engine loads of 25% to 100%, as 
defined in paragraph (d) of this section. Figure 1 of this paragraph 
(f)(1) depicts a sample Maximum Allowable Emission Limit curve, for 
illustration purposes only, as follows:

BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TP29OC99.006


BILLING CODE 6560-50-C
    (2) If the weighted average emissions, calculated according to 
paragraph (e)(5) of this section, for any gaseous pollutant is lower 
than required by Sec. 86.004-11(a)(3), each of the 13 test values for 
that pollutant shall first be multiplied by the ratio of the applicable 
emission standard (under Sec. 86.004-11(a)(3)) to the weighted average 
emissions value, and then by 1.05 for interpolation allowance, before 
determining the Maximum Allowable Emission Limits under paragraph 
(f)(1) of this section.
    (3) If the Maximum Allowable Emission Limit for any point, as 
calculated under paragraphs (f)(1) and (2) of this section, is greater 
than the applicable Not-to-Exceed limit (if within the Not-to-Exceed 
control area defined in Sec. 86.1370-2004(b)), then the Maximum 
Allowable Emission Limit for that point shall be defined as the 
applicable Not-to-Exceed limit.
    (g) Calculating intermediate test points. (1) For the three test 
points selected by EPA under paragraph (b)(2) of this section, the 
emissions must be measured and calculated according to Sec. 86.1342 and 
also determined by interpolation from the modes of the test cycle 
closest to the respective test point according to paragraph (g)(2) of 
this section. The measured values then must be compared to the 
interpolated values according to paragraph (g)(3) of this section.
    (2) Interpolating emission values from the test cycle. The gaseous 
emissions for each regulated pollutant for each of the control points 
(Z) must be interpolated from the four closest modes of the test cycle 
that envelop the selected control point Z as shown in Figure 2 of this 
paragraph (g)(2).
    (i) For these modes (R, S, T, U), the following definitions apply:

Speed (R) = Speed(T) = nRT
Speed (S) = Speed(U) = nSU
Per cent load (R) = Per cent load (S)
Per cent load (T) = Per cent load (U)

    (ii) The gaseous emissions of the selected control point (Z) must 
be calculated as follows:

EZ = ERS + (ETU-ERS) * 
(MZ-MRS)/(MTU-MRS)
ETU = ET + 
(EU-ET)*(nZ-nRT)/
(nSU-nRT)
ERS = ER + 
(ES-ER)*(nZ-nRT)/
(nSU-nRT)
MTU = 
MT+(MU-MT)*(nZ-nRT
)/(nSU-nRT)
(E) MRS = 
MR+(MS-MR)*(nZ-nRT
)/(nSU-nRT)

Where:

ER, ES, ET, EU = for each 
regulated pollutant, specific gaseous emissions of the enveloping modes

[[Page 58550]]

calculated in accordance with Sec. 86.1342.
MR, MS, MT, MU = engine 
torque of the enveloping modes.

    (iii) Figure 2 follows:

BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TP29OC99.007


BILLING CODE 6560-50-C
    (3) Comparing calculated and interpolated emission values. The 
measured specific gaseous emissions of the control point Z 
(XZ) must be compared to the interpolated value 
(EZ) as follows:

Xdiff = 100*(XZ-EZ)/EZ

    30. A new Sec. 86.1361-2004 is added to subpart N, to read as 
follows:


Sec. 86.1361-2004  Maximum allowable emission limits; compliance in 
actual operation.

    (a) Applicability. This section applies to diesel heavy-duty 
engines.
    (b) General. Compliance with the Maximum Allowable Emission Limits 
under Sec. 86.004-11(a)(3)(ii) may be determined under any conditions 
that may reasonably be expected to be encountered in normal vehicle 
operation and use. The engine may be tested in a vehicle in actual use 
or on a dynamometer, under steady state or transient conditions, and 
under varying ambient conditions. To determine compliance, test results 
within the control area, defined in Sec. 86.1360-2004(d), shall be 
compared to the Maximum Allowable Emission Limits, as determined in 
Sec. 86.1360-2004(f), for the same engine speed and load. The engine, 
when operated within the control area, must comply with the Maximum 
Allowable Emission Limits.
    (c) Test conditions. Where the test conditions identified in 
paragraph (b) of this section require departure from specific 
provisions of this subpart (e.g., sampling time), testing shall be 
conducted using good engineering practices. The manufacturer shall 
submit a detailed description of any departures from the specific 
testing provisions of this subpart and the justification for modifying 
the test procedures, along with any test results submitted to EPA.
    (1) If EPA requires engine dynamometer testing by the manufacturer 
outside of FTP conditions, such testing may be done at the 
manufacturer's facility on existing equipment, and must be carried out 
only within the limits of operation of the manufacturer's available 
test equipment with regard to ambient temperature, humidity and 
altitude. EPA may conduct its own testing at any ambient temperature, 
humidity or altitude.
    (2) When tested under transient conditions, emission values to be 
compared to the Maximum Allowable Emission Limits shall represent an 
average of at least 30 seconds.
    (3) NOX emissions shall be corrected for humidity to a 
standard level of 75 grains of water per pound of dry air. Outside the 
temperature range of 68-86 degrees F, NOX and PM emissions 
shall be corrected to 68 degrees F if below 68 degrees F, or to 86 
degrees F if above 86 degrees F. Where a manufacturer test requires 
such correction factors, the manufacturer must use good engineering 
judgement and generally accepted engineering practice to determine the 
appropriate correction factors, subject to EPA review.
    31. A new Sec. 86.1370-2004 is added to subpart N, to read as 
follows:


Sec. 86.1370-2004  Not-To-Exceed test procedures.

    (a) General. The purpose of this test procedure is to measure in-
use emissions of heavy-duty diesel engines while operating within a 
broad range of speed and load points (the Not-To-Exceed Control Area) 
and under conditions which can reasonably be expected to be encountered 
in normal vehicle operation and use. Emission results from this test 
procedure are to be compared to the Not-To-Exceed Limits specified in 
Sec. 86.004-11 (a)(4).
    (b) Not-To-Exceed Control Area for diesel heavy-duty engines. The 
Not-To-Exceed Control Area for diesel heavy-

[[Page 58551]]

duty engines consists of the following engine speed and load points:
    (1) All operating speeds greater than the speed calculated using 
the following formula, where nhi and nlo are 
determined according to the provisions in Sec. 86.1360(c):

nlo+0.15nhi(nhi-nlo)

    (2) All engine load points greater than or equal to 30% or more of 
the maximum torque value produced by the engine.
    (3) Notwithstanding the provisions of paragraphs (b)(1) and (b)(2) 
of this section, all operating speed and load points with brake 
specific fuel consumption (BSFC) values within 5% of the minimum BSFC 
value of the engine. The manufacturer may petition the Administrator at 
certification to exclude such points if the manufacturer can 
demonstrate that the engine is not expected to operate at such points 
in normal vehicle operation and use. Engines equipped with drivelines 
with multi-speed manual transmissions or automatic transmissions with a 
finite number of gears are not subject the requirements of this 
paragraph (b)(3).
    (4) Notwithstanding the provisions of paragraphs (b)(1) through 
(b)(3) of this section, speed and load points below 30% of the maximum 
power value produced by the engine shall be excluded from the Not-To-
Exceed Control Area for all emissions.
    (5) For particulate matter only, speed and load points determined 
by one of the following methods, whichever is applicable, shall be 
excluded from the Not-To-Exceed Control Area. B and C engine speeds 
shall be determined according to the provisions of Sec. 86.1350 (c):
    (i) If the C speed is below 2400 rpm, the speed and load points to 
the right of or below the line formed by connecting the following two 
points:
    (A) 30% of maximum torque or 30% of maximum power, whichever is 
greater, at the B speed;
    (B) 70% of maximum power at 100% speed (nhi);
    (ii) If the C speed is above 2400 rpm, the speed and load points to 
the right of the line formed by connecting the two points in paragraphs 
(b)(5)(ii)(A) and (B) of this section and below the line formed by 
connecting the two points in paragraphs (b)(5)(ii)(B) and (C) of this 
section:
    (A) 30% of maximum torque or 30% of maximum power, whichever is 
greater, at the B speed;
    (B) 50% of maximum power at 2400 rpm;
    (C) 70% of maximum power at 100% speed (nhi).
    (c) [Reserved]
    (d) Not-To-Exceed Control Area Limits. (1) When operated within the 
Not-To-Exceed Control Area defined in paragraph (b) of this section, 
diesel engine emissions shall not exceed the applicable Not-To-Exceed 
Limits specified in Sec. 86.004-11 (a)(4) when averaged over any period 
of time greater than or equal to 30 seconds.
    (2) [Reserved]
    (e) Ambient Corrections. The measured data shall be corrected based 
on the ambient conditions under which it was taken. The temperature and 
humidity correction factors will be based on good engineering practice.
    (1) NOX emissions shall be corrected for humidity to a 
standard humidity level of 50 grains (7.14 g/kg) if the humidity of the 
intake air was below 50 grains, or to 75 grains (10.71 g/kg) if above 
75 grains.
    (2) NOX and PM emissions shall be corrected for 
temperature to a temperature of 55 degrees F (12.8 degrees C) for 
intake air temperatures below 55 degrees F or to 95 degrees F (35.0 
degrees C) if the intake air is above 95 degrees F.
    (3) No temperature or humidity correction factors shall be used 
within the ranges of 50-75 grains or 55-95 degrees F.
    33. A new Sec. 86.1372-2004 is added to subpart N, to read as 
follows:


Sec. 86.1372-2004  Measuring smoke emissions.

    This section contains the measurement techniques to be used for 
determining compliance with the filter smoke limit or opacity limits in 
Sec. 86.004-11(b)(1)(iv).
    (a) For steady-state or transient smoke testing using full-flow 
opacimeters, equipment meeting the requirements of subpart I of this 
part or ISO/DIS-11614 ``Reciprocating internal combustion compression-
ignition engines--Apparatus for measurement of the opacity and for 
determination of the light absorption coefficient of exhaust gas' is 
required. This document is incorporated by reference (see Sec. 86.1).
    (1) All full-flow opacimeter measurements shall be reported as the 
equivalent percent opacity for a five inch effective optical path 
length using the Beer-Lambert relationship.
    (2) Zero and full-scale (100 percent opacity) span shall be 
adjusted prior to testing.
    (3) Post test zero and full scale span checks shall be performed. 
For valid tests, zero and span drift between the pre-test and post-test 
checks shall be less than two percent of full-scale.
    (4) Opacimeter calibration and linearity checks shall be performed 
using manufacturer's recommendations or good engineering practice.
    (b) For steady-state testing using a filter-type smokemeter, 
equipment meeting the requirements of ISO/FDIS-10054 ``Internal 
combustion compression-ignition engines--Measurement apparatus for 
smoke from engines operating under steady-state conditions--Filter-type 
smokemeter'' is recommended.
    (1) All filter-type smokemeter results shall be reported as a 
filter smoke number (FSN) that is similar to the Bosch smoke number 
(BSN) scale.
    (2) Filter-type smokemeters shall be calibrated every 90 days using 
manufacturer's recommended practices or good engineering practice.
    (c) For steady-state testing using a partial-flow opacimeter, 
equipment meeting the requirements of ISO-8178-3 and ISO/DIS-11614 is 
recommended.
    (1) All partial-flow opacimeter measurements shall be reported as 
the equivalent percent opacity for a five inch effective optical path 
length using the Beer-Lambert relationship.
    (2) Zero and full scale (100 percent opacity) span shall be 
adjusted prior to testing.
    (3) Post-test zero and full scale span checks shall be performed. 
For valid tests, zero and span drift between the pre-test and post-test 
checks shall be less than two percent of full scale.
    (4) Opacimeter calibration and linearity checks shall be performed 
using manufacturer's recommendations or good engineering practice.
    (d) Replicate smoke tests may be run to improve confidence in a 
single test or stabilization. If replicate tests are run, three 
additional valid tests shall be run, and the final reported test 
results must be the average of all the valid tests.
    (e) A minimum of thirty seconds sampling time shall be used for 
average transient smoke measurements.
    34. A new Sec. 86.1380-2004 is added to subpart N, to read as 
follows:


Sec. 86.1380-2004  Load response test.

    (a) General. The purpose of this test procedure is to measure the 
gaseous and particulate emissions from an engine as it is suddenly 
loaded, with its fueling lever, at a given engine operating speed. This 
procedure shall be conducted on a dynamometer.
    (b) Test sequence. (1) At each of the following speeds, the engine 
fuel control shall be moved suddenly to the full fuel position and held 
at that point for a minimum of two seconds, while the specified speed 
is maintained constant:
    (i) The lowest speed in the Not-To-Exceed Control area determined 
according to the provisions of Sec. 86.1370;

[[Page 58552]]

    (ii) Speed A as determined in Sec. 86.1360(c);
    (iii) Speed B as determined in Sec. 86.1360(c);
    (iv) Speed C as determined in Sec. 86.1360(c);
    (v) Speed D as determined in Sec. 86.1360(c);
    (vi) Speed E as determined in Sec. 86.1360(c).
    (2) This test sequence may be repeated if it is necessary to obtain 
sufficient sample amount for analysis.
    (3) The exhaust emissions sample shall be analyzed according to the 
procedures under Sec. 86.1340, and the exhaust emission shall be 
calculated according to the procedures under Sec. 86.1342.

Subpart P--[Amended]

    35. Section 86.1501-94 is revised to read as follows:


Sec. 86.1501-94  Scope; applicability.

    (a) This subpart contains gaseous emission idle test procedures for 
light-duty trucks and heavy-duty engines for which idle CO standards 
apply. It applies to 1994 and later model years. The idle test 
procedures are optionally applicable to 1994 through 1996 model year 
natural gas-fueled and liquified petroleum gas-fueled light-duty trucks 
and heavy-duty engines.
    (b) References in this subpart to engine families and emission 
control systems shall be deemed to apply to durability groups and test 
groups as applicable for manufacturers certifying new light-duty trucks 
and Otto-cycle complete heavy-duty vehicles under the provisions of 
Subpart S of this part.

Subpart Q--[Amended]

    36. Section 86.1601 is amended by revising paragraph (d), to read 
as follows:


Sec. 86.1601  General applicability.

* * * * *
    (d) References in this subpart to engine families and emission 
control systems shall be deemed to apply to durability groups and test 
groups as applicable for manufacturers certifying new light-duty 
vehicles, light-duty trucks, and Otto-cycle complete heavy-duty 
vehicles under the provisions of Subpart S of this part.
    37. Subpart S is amended by revising the subpart heading to read as 
follows:

Subpart S--General Compliance Provisions for Control of Air 
Pollution From New and In-Use Light-Duty Vehicles, Light-Duty 
Trucks, and Complete Otto-Cycle Heavy-Duty Vehicles

    38. Section 86.1801-01 is amended by revising paragraphs (a), (b), 
(c), and the last sentence of paragraph (d), to read as follows:


Sec. 86.1801-01  Applicability.

    (a) Applicability. The provisions of this subpart apply to 2001 and 
later model year new Otto-cycle and diesel-cycle light-duty vehicles, 
2001 and later model year new Otto-cycle and diesel-cycle light-duty 
trucks, and 2004 and later model year Otto-cycle complete heavy-duty 
vehicles. These provisions also apply to 2001 model year and later new 
incomplete light-duty trucks below 8,500 Gross Vehicle Weight Rating, 
and to 2000 and later model year Otto-cycle complete heavy-duty 
vehicles participating in the early banking provisions of the 
averaging, trading, and banking program under the provisions of 
Sec. 86.1817-04(n). In cases where a provision applies only to a 
certain vehicle group based on its model year, vehicle class, motor 
fuel, engine type, or other distinguishing characteristics, the limited 
applicability is cited in the appropriate section of this subpart.
    (b) Aftermarket conversions. The provisions of this subpart apply 
to aftermarket conversions of all model year Otto-cycle and diesel-
cycle light-duty vehicles, light-duty trucks, and complete Otto-cycle 
heavy-duty vehicles as defined in 40 CFR 85.502.
    (c) Optional applicability. (1) A manufacturer may request to 
certify any Otto-cycle heavy-duty vehicle of 14,000 pounds Gross 
Vehicle Weight Rating or less in accordance with the light-duty truck 
provisions through the 2003 model year. Heavy-duty engine or heavy-duty 
vehicle provisions of subpart A of this part do not apply to such a 
vehicle.
    (2) Beginning with the 2001 model year, a manufacturer may request 
to certify any incomplete Otto-cycle heavy-duty vehicle of 14,000 
pounds Gross Vehicle Weight Rating or less in accordance with the 
provisions for complete heavy-duty vehicles. Heavy-duty engine or 
heavy-duty vehicle provisions of subpart A of this part do not apply to 
such a vehicle.
    (3) A manufacturer may optionally use the provisions of this 
subpart in lieu of the provisions of subpart A beginning with the 2000 
model year for light-duty vehicles and light-duty trucks. Manufacturers 
choosing this option must comply with all provisions of this subpart. 
Manufacturers may elect this provision for either all or a portion of 
their product line.
    (4) Upon preapproval by the Administrator, a manufacturer may 
optionally certify an aftermarket conversion of a complete heavy-duty 
vehicle greater than 10,000 pounds Gross Vehicle Weight Rating and of 
14,000 pounds Gross Vehicle Weight Rating or less under the heavy-duty 
engine or heavy-duty vehicle provisions of subpart A of this part. Such 
preapproval will be granted only upon demonstration that chassis-based 
certification would be infeasible or unreasonable for the manufacturer 
to perform.
    (5) A manufacturer may optionally certify an aftermarket conversion 
of a complete heavy-duty vehicle greater than 10,000 pounds Gross 
Vehicle Weight Rating and of 14,000 pounds Gross Vehicle Weight Rating 
or less under the heavy-duty engine or heavy-duty vehicle provisions of 
subpart A of this part without advance approval from the Administrator 
if the vehicle was originally certified to the heavy-duty engine or 
heavy-duty vehicle provisions of subpart A of this part.
    (d) * * * The small volume manufacturer's light-duty vehicle, 
light-duty truck and complete heavy-duty vehicle certification 
procedures are described in Sec. 86.1838-01.
* * * * *
    39. Section 86.1803-01 is amended by revising the definitions for 
``Car line,'' ``Curb idle,'' ``Durability useful life,'' and ``Van,'' 
and by adding new definitions in alphabetical order, to read as 
follows:


Sec. 86.1803-01  Definitions.

* * * * *
    Averaging for chassis-bases heavy-duty vehicles means the exchange 
of NOX emission credits among test groups within a given 
manufacturer's product line.
    Averaging set means a subcategory of complete heavy-duty vehicles 
within which test groups can average and trade emission credits with 
one another.
* * * * *
    Banking means the retention of NOX emission credits for 
complete heavy-duty vehicles by the manufacturer generating the 
emission credits, for use in future model year certification programs 
as permitted by regulation.
* * * * *
    Car line means a name denoting a group of vehicles within a make or 
car division which has a degree of commonality in construction (e.g., 
body,

[[Page 58553]]

chassis). Car line does not consider any level of decor or opulence and 
is not generally distinguished by characteristics as roofline, number 
of doors, seats, or windows except for station wagons or light-duty 
trucks. Station wagons, light-duty trucks, and complete heavy-duty 
vehicles are considered to be different car lines than passenger cars.
* * * * *
    Complete heavy-duty vehicle means any Otto-cycle heavy-duty vehicle 
of 14,000 pounds Gross Vehicle Weight Rating or less that is not an 
incomplete heavy-duty vehicle.
* * * * *
    Curb-idle means, for manual transmission code motor vehicles, the 
engine speed with the transmission in neutral or with the clutch 
disengaged and with the air conditioning system, if present, turned 
off. For automatic transmission code motor vehicles, curb-idle means 
the engine speed with the automatic transmission in the park position 
(or neutral position if there is no park position), and with the air 
conditioning system, if present, turned off.
* * * * *
    Durability useful life means the highest useful life mileage out of 
the set of all useful life mileages that apply to a given vehicle. The 
durability useful life determines the duration of service accumulation 
on a durability data vehicle. The determination of durability useful 
life shall reflect any light-duty truck or complete heavy-duty vehicle 
alternative useful life periods approved by the Administrator under 
Sec. 86.1805-01(c). The determination of durability useful life shall 
exclude any standard and related useful life mileage for which the 
manufacturer has obtained a waiver of emission data submission 
requirements under Sec. 86.1829-01.
* * * * *
    Emission credits mean the amount of emission reductions or 
exceedances, by a complete heavy-duty vehicle test group, below or 
above the emission standard, respectively. Emission credits below the 
standard are considered as ``positive credits,'' while emission credits 
above the standard are considered as ``negative credits.'' In addition, 
``projected credits'' refer to emission credits based on the projected 
U.S. production volume of the test group. ``Reserved credits'' are 
emission credits generated within a model year waiting to be reported 
to EPA at the end of the model year. ``Actual credits'' refer to 
emission credits based on actual U.S. production volumes as contained 
in the end-of-year reports submitted to EPA. Some or all of these 
credits may be revoked if EPA review of the end of year reports or any 
subsequent audit actions uncover problems or errors.
* * * * *
    Family emission limit (FEL) means an emission level declared by the 
manufacturer which serves in lieu of an emission standard for 
certification purposes in the averaging, trading and banking program. 
FELs must be expressed to the same number of decimal places as the 
applicable emission standard.
* * * * *
    Incomplete heavy-duty vehicle means any heavy-duty vehicle which 
does not have the primary load carrying device or container attached.
* * * * *
    Non-methane organic gas means the sum of oxegenated and non-
oxygenated hydrocarbons contained in a gas sample.
* * * * *
    Trading means the exchange of complete heavy-duty vehicle 
NOX emission credits between manufacturers.
* * * * *
    Van means a light-duty truck or complete heavy-duty vehicle having 
an integral enclosure, fully enclosing the driver compartment and load 
carrying device, and having no body sections protruding more than 30 
inches ahead of the leading edge of the windshield.
* * * * *
    40. A new section 86.1803-04 is added to subpart S, to read as 
follows:


Sec. 86.1803-04  Definitions.

    The definitions of Sec. 86.1803-01 continue to apply to this 
subpart. The definitions listed in this section apply to this subpart 
beginning with the 2004 model year.
    Heavy-duty vehicle means any motor vehicle rated at more than 8,500 
pounds GVWR or that has a vehicle curb weight of more than 6,000 pounds 
or that has a basic vehicle frontal area in excess of 45 square feet, 
excluding vehicles with a GVWR greater than 8,500 pounds and less than 
or equal to 10,000 pounds that are defined as light-duty trucks.
    Light-duty truck means:
    (1) Any motor vehicle rated at 8,500 pounds GVWR or less which has 
a curb weight of 6,000 pounds or less and which has a basic vehicle 
frontal area of 45 square feet or less, which is:
    (i) Designed primarily for purposes of transportation of property 
or is a derivation of such a vehicle; or
    (ii) Designed primarily for transportation of persons and has a 
capacity of more than 12 persons; or
    (iii) Available with special features enabling off-street or off-
highway operation and use; or
    (2) Any motor vehicle rated at greater than 8,500 pounds GVWR and 
less than or equal to 10,000 pounds GVWR which is a complete vehicle 
designed primarily for transportation of persons and has a capacity of 
not more than 12 persons.
    41. Section 86.1804-01 is amended by adding ``FEL,'' ``NMOG,'' and 
``HDV'' as new abbreviations in alphabetical order, to read as follows:


Sec. 86.1804-01  Acronyms and abbreviations.

* * * * *
FEL--Family Emission Limit
* * * * *
HDV--Heavy-duty vehicle
* * * * *
NMOG--Non-Methane Organic Gas
* * * * *
    42. Section 86.1805-01 is amended by revising paragraph (a) and the 
first and last sentences of paragraph (c), and adding paragraph (b)(3), 
to read as follows:


Sec. 86.1805-01  Useful life.

    (a) For light-duty vehicles and light-duty trucks, intermediate 
useful life is a period of use of 5 years or 50,000 miles, which ever 
occurs first.
    (b) * * *
    (3) For complete heavy-duty vehicles, the full useful life is a 
period of use of 11 years or 120,000 miles, which ever occurs first.
    (c) Manufacturers may petition the Administrator to provide 
alternative useful life periods for light-duty trucks or complete 
heavy-duty vehicles when they believe that the useful life periods are 
significantly unrepresentative for one or more test groups (either too 
long or too short). * * * For light-duty trucks, alternative useful 
life periods will be granted only for THC, THCE, and idle CO 
requirements.
    43. A new Sec. 86.1806-04 is added to subpart S, to read as 
follows:


Sec. 86.1806-04  On-board diagnostics.

    (a) General. All light-duty vehicles, light-duty trucks, and heavy-
duty vehicles intended for use in a heavy-duty vehicle weighing 14,000 
pounds GVWR or less must be equipped with an on-board diagnostic (OBD) 
system capable of monitoring all emission-related powertrain systems or 
components during the applicable useful life. Heavy-duty vehicles 
intended for use in a heavy-duty vehicle weighing 14,000 pounds GVWR or 
less must meet the OBD requirements of this section according to the 
phase-in schedule in paragraph (l) of this section. All monitored 
systems and components

[[Page 58554]]

must be evaluated periodically, but no less frequently than once per 
applicable certification test cycle as defined in paragraphs (a) and 
(d) of Appendix I of this part.
    (b) Malfunction descriptions. The OBD system must detect and 
identify malfunctions in all monitored emission-related powertrain 
systems or components according to the following malfunction 
definitions as measured and calculated in accordance with test 
procedures set forth in subpart B of this part (chassis-based test 
procedures), excluding those test procedures defined as 
``Supplemental'' test procedures in Sec. 86.004-2 and codified in 
Secs. 86.158, 86.159, and 86.160.
    (1) Catalysts and particulate traps. (i) Otto-cycle. Catalyst 
deterioration or malfunction before it results in an increase in NMHC 
emissions 1.5 times the NMHC standard or FEL, as compared to the NMHC 
emission level measured using a representative 4000 mile catalyst 
system.
    (ii) Diesel. If equipped, catalyst or particulate trap 
deterioration or malfunction before it results in exhaust emissions 
exceeding 1.5 times the applicable standard or FEL for NOX 
or PM. This monitoring need not be done if the manufacturer can 
demonstrate that deterioration or malfunction of the system will not 
result in exceedance of the threshold; however, the presence of the 
catalyst or particulate trap must still be monitored.
    (2) Engine misfire. (i) Otto-cycle. Engine misfire resulting in 
exhaust emissions exceeding 1.5 times the applicable standard or FEL 
for NMHC, CO or NOX; and any misfire capable of damaging the 
catalytic converter.
    (ii) Diesel. Lack of cylinder combustion must be detected.
    (3) Oxygen sensors. If equipped, oxygen sensor deterioration or 
malfunction resulting in exhaust emissions exceeding 1.5 times the 
applicable standard or FEL for NMHC, CO or NOX.
    (4) Evaporative leaks. If equipped, any vapor leak in the 
evaporative and/or refueling system (excluding the tubing and 
connections between the purge valve and the intake manifold) greater 
than or equal in magnitude to a leak caused by a 0.040 inch diameter 
orifice; an absence of evaporative purge air flow from the complete 
evaporative emission control system. On vehicles with fuel tank 
capacity greater than 25 gallons, the Administrator may, following a 
request from the manufacturer, revise the size of the orifice to the 
smallest orifice feasible, based on test data, if the most reliable 
monitoring method available cannot reliably detect a system leak equal 
to a 0.040 inch diameter orifice.
    (5) Other emission control systems. Any deterioration or 
malfunction occurring in a powertrain system or component directly 
intended to control emissions, including but not necessarily limited 
to, the exhaust gas recirculation (EGR) system, if equipped, the 
secondary air system, if equipped, and the fuel control system, 
singularly resulting in exhaust emissions exceeding 1.5 times the 
applicable emission standard or FEL for NMHC, CO, NOX, or 
diesel PM. For vehicles equipped with a secondary air system, a 
functional check, as described in paragraph (b)(6) of this section, may 
satisfy the requirements of this paragraph provided the manufacturer 
can demonstrate that deterioration of the flow distribution system is 
unlikely. This demonstration is subject to Administrator approval and, 
if the demonstration and associated functional check are approved, the 
diagnostic system must indicate a malfunction when some degree of 
secondary airflow is not detectable in the exhaust system during the 
check. For vehicles equipped with positive crankcase ventilation (PCV), 
monitoring of the PCV system is not necessary provided the manufacturer 
can demonstrate to the Administrator's satisfaction that the PCV system 
is unlikely to fail.
    (6) Other emission-related powertrain components. Any other 
deterioration or malfunction occurring in an electronic emission-
related powertrain system or component not otherwise described above 
that either provides input to or receives commands from the on-board 
computer and has a measurable impact on emissions; monitoring of 
components required by this paragraph must be satisfied by employing 
electrical circuit continuity checks and rationality checks for 
computer input components (input values within manufacturer specified 
ranges based on other available operating parameters), and 
functionality checks for computer output components (proper functional 
response to computer commands) except that the Administrator may waive 
such a rationality or functionality check where the manufacturer has 
demonstrated infeasibility. Malfunctions are defined as a failure of 
the system or component to meet the electrical circuit continuity 
checks or the rationality or functionality checks.
    (7) Performance of OBD functions. Oxygen sensor or any other 
component deterioration or malfunction which renders that sensor or 
component incapable of performing its function as part of the OBD 
system must be detected and identified on vehicles so equipped.
    (c) Malfunction indicator light (MIL). The OBD system must 
incorporate a malfunction indicator light (MIL) readily visible to the 
vehicle operator. When illuminated, the MIL must display ``Check 
Engine,'' ``Service Engine Soon,'' a universally recognizable engine 
symbol, or a similar phrase or symbol approved by the Administrator. A 
vehicle should not be equipped with more than one general purpose 
malfunction indicator light for emission-related problems; separate 
specific purpose warning lights (e.g. brake system, fasten seat belt, 
oil pressure, etc.) are permitted. The use of red for the OBD-related 
malfunction indicator light is prohibited.
    (d) MIL illumination. The MIL must illuminate and remain 
illuminated when any of the conditions specified in paragraph (b) of 
this section are detected and verified, or whenever the engine control 
enters a default or secondary mode of operation considered abnormal for 
the given engine operating conditions. The MIL must blink once per 
second under any period of operation during which engine misfire is 
occurring and catalyst damage is imminent. If such misfire is detected 
again during the following driving cycle (i.e., operation consisting 
of, at a minimum, engine start-up and engine shut-off) or the next 
driving cycle in which similar conditions are encountered, the MIL must 
maintain a steady illumination when the misfire is not occurring and 
then remain illuminated until the MIL extinguishing criteria of this 
section are satisfied. The MIL must also illuminate when the vehicle's 
ignition is in the ``key-on'' position before engine starting or 
cranking and extinguish after engine starting if no malfunction has 
previously been detected. If a fuel system or engine misfire 
malfunction has previously been detected, the MIL may be extinguished 
if the malfunction does not reoccur during three subsequent sequential 
trips during which similar conditions are encountered and no new 
malfunctions have been detected. Similar conditions are defined as 
engine speed within 375 rpm, engine load within 20 percent, and engine 
warm-up status equivalent to that under which the malfunction was first 
detected. If any malfunction other than a fuel system or engine misfire 
malfunction has been detected, the MIL may be extinguished if the 
malfunction does not reoccur during three subsequent sequential trips 
during which the monitoring system responsible for illuminating the MIL

[[Page 58555]]

functions without detecting the malfunction, and no new malfunctions 
have been detected. Upon Administrator approval, statistical MIL 
illumination protocols may be employed, provided they result in 
comparable timeliness in detecting a malfunction and evaluating system 
performance, i.e., three to six driving cycles would be considered 
acceptable.
    (e) Storing of computer codes. The OBD system shall record and 
store in computer memory diagnostic trouble codes and diagnostic 
readiness codes indicating the status of the emission control system. 
These codes shall be available through the standardized data link 
connector per specifications as referenced in paragraph (h) of this 
section.
    (1) A diagnostic trouble code must be stored for any detected and 
verified malfunction causing MIL illumination. The stored diagnostic 
trouble code must identify the malfunctioning system or component as 
uniquely as possible. At the manufacturer's discretion, a diagnostic 
trouble code may be stored for conditions not causing MIL illumination. 
Regardless, a separate code should be stored indicating the expected 
MIL illumination status (i.e., MIL commanded ``ON,'' MIL commanded 
``OFF'').
    (2) For a single misfiring cylinder, the diagnostic trouble code(s) 
must uniquely identify the cylinder, unless the manufacturer submits 
data and/or engineering evaluations which adequately demonstrate that 
the misfiring cylinder cannot be reliably identified under certain 
operating conditions. For diesel vehicles only, the specific cylinder 
for which combustion cannot be detected need not be identified if new 
hardware would be required to do so. The diagnostic trouble code must 
identify multiple misfiring cylinder conditions; under multiple misfire 
conditions, the misfiring cylinders need not be uniquely identified if 
a distinct multiple misfire diagnostic trouble code is stored.
    (3) The diagnostic system may erase a diagnostic trouble code if 
the same code is not re-registered in at least 40 engine warm-up 
cycles, and the malfunction indicator light is not illuminated for that 
code.
    (4) Separate status codes, or readiness codes, must be stored in 
computer memory to identify correctly functioning emission control 
systems and those emission control systems which require further 
vehicle operation to complete proper diagnostic evaluation. A readiness 
code need not be stored for those monitors that can be considered 
continuously operating monitors (e.g., misfire monitor, fuel system 
monitor, etc.). Readiness codes should never be set to ``not ready'' 
status upon key-on or key-off; intentional setting of readiness codes 
to ``not ready'' status via service procedures must apply to all such 
codes, rather than applying to individual codes. Subject to 
Administrator approval, if monitoring is disabled for a multiple number 
of driving cycles (i.e., more than one) due to the continued presence 
of extreme operating conditions (e.g., ambient temperatures below 
40 deg.F, or altitudes above 8000 feet), readiness for the subject 
monitoring system may be set to ``ready'' status without monitoring 
having been completed. Administrator approval shall be based on the 
conditions for monitoring system disablement, and the number of driving 
cycles specified without completion of monitoring before readiness is 
indicated.
    (f) Available diagnostic data. (1) Upon determination of the first 
malfunction of any component or system, ``freeze frame'' engine 
conditions present at the time must be stored in computer memory. 
Should a subsequent fuel system or misfire malfunction occur, any 
previously stored freeze frame conditions must be replaced by the fuel 
system or misfire conditions (whichever occurs first). Stored engine 
conditions must include, but are not limited to: engine speed, open or 
closed loop operation, fuel system commands, coolant temperature, 
calculated load value, fuel pressure, vehicle speed, air flow rate, and 
intake manifold pressure if the information needed to determine these 
conditions is available to the computer. For freeze frame storage, the 
manufacturer must include the most appropriate set of conditions to 
facilitate effective repairs. If the diagnostic trouble code causing 
the conditions to be stored is erased in accordance with paragraph (d) 
of this section, the stored engine conditions may also be erased.
    (2) The following data in addition to the required freeze frame 
information must be made available on demand through the serial port on 
the standardized data link connector, if the information is available 
to the on-board computer or can be determined using information 
available to the on-board computer: Diagnostic trouble codes, engine 
coolant temperature, fuel control system status (closed loop, open 
loop, other), fuel trim, ignition timing advance, intake air 
temperature, manifold air pressure, air flow rate, engine RPM, throttle 
position sensor output value, secondary air status (upstream, 
downstream, or atmosphere), calculated load value, vehicle speed, and 
fuel pressure. The signals must be provided in standard units based on 
SAE specifications incorporated by reference in paragraph (h) of this 
section. Actual signals must be clearly identified separately from 
default value or limp home signals.
    (3) For all OBD systems for which specific on-board evaluation 
tests are conducted (catalyst, oxygen sensor, etc.), the results of the 
most recent test performed by the vehicle, and the limits to which the 
system is compared must be available through the standardized data link 
connector per the appropriate standardized specifications as referenced 
in paragraph (h) of this section.
    (4) Access to the data required to be made available under this 
section shall be unrestricted and shall not require any access codes or 
devices that are only available from the manufacturer.
    (g) Exceptions. The OBD system is not required to evaluate systems 
or components during malfunction conditions if such evaluation would 
result in a risk to safety or failure of systems or components. 
Additionally, the OBD system is not required to evaluate systems or 
components during operation of a power take-off unit such as a dump 
bed, snow plow blade, or aerial bucket, etc.
    (h) Reference materials. The OBD system shall provide for 
standardized access and conform with the following Society of 
Automotive Engineers (SAE) standards and/or the following International 
Standards Organization (ISO) standards. The following documents are 
incorporated by reference (see Sec. 86.1):
    (1) SAE material. Copies of these materials may be obtained from 
the Society of Automotive Engineers, Inc., 400 Commonwealth Drive, 
Warrendale, PA 15096-0001.
    (i) SAE J1850 ``Class B Data Communication Network Interface,'' 
(July 1995) shall be used as the on-board to off-board communications 
protocol. All emission related messages sent to the scan tool over a 
J1850 data link shall use the Cyclic Redundancy Check and the three 
byte header, and shall not use inter-byte separation or checksums.
    (ii) Basic diagnostic data (as specified in Secs. 86.094-17(e) and 
(f)) shall be provided in the format and units in SAE J1979 E/E 
Diagnostic Test Modes,''(July 1996).
    (iii) Diagnostic trouble codes shall be consistent with SAE J2012 
``Recommended Practices for Diagnostic Trouble Code Definitions,'' 
(July 1996).
    (iv) The connection interface between the OBD system and test 
equipment and

[[Page 58556]]

diagnostic tools shall meet the functional requirements of SAE J1962 
``Diagnostic Connector,'' (January 1995).
    (v) As an alternative to the above standards, heavy-duty vehicles 
may conform to the specifications of SAE J1939 ``Recommended Practice 
for a Serial Control and Communications Vehicle Network.''
    (2) ISO materials. Copies of these materials may be obtained from 
the International Organization for Standardization, Case Postale 56, 
CH-1211 Geneva 20, Switzerland.
    (i) ISO 9141-2 ``Road vehicles--Diagnostic systems--Part 2: CARB 
requirements for interchange of digital information,'' (February 1994) 
may be used as an alternative to SAE J1850 as the on-board to off-board 
communications protocol.
    (ii) ISO 14230-4 ``Road vehicles--Diagnostic systems--KWP 2000 
requirements for Emission-related systems'' may also be used as an 
alternative to SAE J1850.
    (i) Deficiencies and alternate fueled vehicles. Upon application by 
the manufacturer, the Administrator may accept an OBD system as 
compliant even though specific requirements are not fully met. Such 
compliances without meeting specific requirements, or deficiencies, 
will be granted only if compliance would be infeasible or unreasonable 
considering such factors as, but not limited to: technical feasibility 
of the given monitor and lead time and production cycles including 
phase-in or phase-out of engines or vehicle designs and programmed 
upgrades of computers. Unmet requirements should not be carried over 
from the previous model year except where unreasonable hardware or 
software modifications would be necessary to correct the deficiency, 
and the manufacturer has demonstrated an acceptable level of effort 
toward compliance as determined by the Administrator. Furthermore, EPA 
will not accept any deficiency requests that include the complete lack 
of a major diagnostic monitor (``major'' diagnostic monitors being 
those for exhaust aftertreatment devices, oxygen sensor, engine 
misfire, evaporative leaks, and diesel EGR, if equipped), with the 
possible exception of the special provisions for alternate fueled 
vehicles. For alternate fueled vehicles (e.g. natural gas, liquefied 
petroleum gas, methanol, ethanol), beginning with the model year for 
which alternate fuel emission standards are applicable and extending 
through the 2004 model year, manufacturers may request the 
Administrator to waive specific monitoring requirements of this section 
for which monitoring may not be reliable with respect to the use of the 
alternate fuel; manufacturers may request this alternate fuel waiver 
for heavy-duty vehicles through the 2006 model year. At a minimum, 
alternate fuel vehicles must be equipped with an OBD system meeting OBD 
requirements to the extent feasible as approved by the Administrator.
    (j) California OBDII Compliance Option. For light-duty vehicles, 
light-duty trucks, and heavy-duty vehicles at or below 14,000 pounds 
GVWR, demonstration of compliance with California OBD II requirements 
(Title 13 California Code Sec. 1968.1), as modified pursuant to 
California Mail Out #97-24 (December 9, 1997), shall satisfy the 
requirements of this section, except that the exemption to the catalyst 
monitoring provisions of California Code Sec. 1968.1(b)(1.1.2) for 
diesel vehicles does not apply, and compliance with California Code 
Secs. 1968.1(b)(4.2.2), pertaining to 0.02 inch evaporative leak 
detection, and 1968.1(d), pertaining to tampering protection, are not 
required to satisfy the requirements of this section. Also, the 
deficiency fine provisions of California Code Sec. 1968.1(m)(6.1) and 
(6.2) do not apply.
    (k) Certification. For test groups required to have an OBD system, 
certification will not be granted if, for any test vehicle approved by 
the Administrator in consultation with the manufacturer, the 
malfunction indicator light does not illuminate under any of the 
following circumstances, unless the manufacturer can demonstrate that 
any identified OBD problems discovered during the Administrator's 
evaluation will be corrected on production vehicles.
    (1)(i) Otto-cycle. A catalyst is replaced with a deteriorated or 
defective catalyst, or an electronic simulation of such, resulting in 
an increase of 1.5 times the NMHC standard or FEL above the NMHC 
emission level measured using a representative 4000 mile catalyst 
system.
    (ii) Diesel. If monitored for emissions performance--a catalyst or 
particulate trap is replaced with a deteriorated or defective catalyst 
or trap, or an electronic simulation of such, resulting in exhaust 
emissions exceeding 1.5 times the applicable standard or FEL for 
NOX or PM. If not monitored for emissions performance--
removal of the catalyst or particulate trap is not detected and 
identified.
    (2)(i) Otto-cycle. An engine misfire condition is induced resulting 
in exhaust emissions exceeding 1.5 times the applicable standards or 
FEL for NMHC, CO or NOX.
    (ii) Diesel. An engine misfire condition is induced and is not 
detected.
    (3) If so equipped, any oxygen sensor is replaced with a 
deteriorated or defective oxygen sensor, or an electronic simulation of 
such, resulting in exhaust emissions exceeding 1.5 times the applicable 
standard or FEL for NMHC, CO or NOX.
    (4) If so equipped, a vapor leak is introduced in the evaporative 
and/or refueling system (excluding the tubing and connections between 
the purge valve and the intake manifold) greater than or equal in 
magnitude to a leak caused by a 0.040 inch diameter orifice, or the 
evaporative purge air flow is blocked or otherwise eliminated from the 
complete evaporative emission control system.
    (5) A malfunction condition is induced in any emission-related 
powertrain system or component, including but not necessarily limited 
to, the exhaust gas recirculation (EGR) system, if equipped, the 
secondary air system, if equipped, and the fuel control system, 
singularly resulting in exhaust emissions exceeding 1.5 times the 
applicable emission standard or FEL for NMHC, CO, NOX or PM.
    (6) A malfunction condition is induced in an electronic emission-
related powertrain system or component not otherwise described in this 
paragraph (k) that either provides input to or receives commands from 
the on-board computer resulting in a measurable impact on emissions.
    (l) Phase-in for Heavy-Duty Vehicles. Manufacturers of heavy-duty 
vehicles intended for use in a heavy-duty vehicle weighing 14,000 
pounds GVWR or less must comply with the OBD requirements in this 
section according to the following phase-in schedule, based on the 
percentage of projected vehicle sales within each category:

[[Page 58557]]



               OBD Compliance Phase-in Heavy-Duty Vehicles
[intended for use in a heavy-duty vehicle weighing 14,000 pounds GVWR or
                                  less]
------------------------------------------------------------------------
                                           Phase-in based on projected
               Model year                             sales
------------------------------------------------------------------------
2004 MY................................  --40% compliance
2005 MY................................  --60% compliance--alternative
                                          fuel waivers available
2006 MY................................  --80% compliance--alternative
                                          fuel waivers available
2007+ MY...............................  --100% compliance--alternative
                                          fuel waivers available
------------------------------------------------------------------------

    44. Section 86.1807-01 is amended by adding paragraph (c)(3), and 
revising paragraphs (a)(3)(v), (d), (e), and (f), to read as follows:


Sec. 86.1807-01  Vehicle labeling.

    (a) * * *
    (3) * * *
    (v) An unconditional statement of compliance with the appropriate 
model year U.S. EPA regulations which apply to light-duty vehicles, 
light-duty trucks, or complete heavy-duty vehicles;
* * * * *
    (c) * * *
    (3) The manufacturer of any complete heavy-duty vehicle subject to 
the emission standards of this subpart shall add the information 
required by paragraph (c)(1)(iii) of this section to the label required 
by paragraph (a) of this section. The required information will be set 
forth in the manner prescribed by paragraph (c)(1)(iii) of this 
section.
    (d)(1) Incomplete light-duty trucks shall have the following 
prominent statement printed on the label required by paragraph 
(a)(3)(v) of this section: ``This vehicle conforms to U.S. EPA 
regulations applicable to 20xx Model year Light-Duty Trucks under the 
special provisions of Sec. 86.1801-01(c)(1) when it does not exceed XXX 
pounds in curb weight, XXX pounds in gross vehicle weight rating, and 
XXX square feet in frontal area.''
    (2) Incomplete heavy-duty vehicles optionally certified in 
accordance with the provisions for complete heavy-duty vehicles under 
the special provisions of Sec. 86.1801-01(c)(2) shall have the 
following prominent statement printed on the label required by 
paragraph (a)(3)(v) of this section: ``This vehicle conforms to U.S. 
EPA regulations applicable to 20xx Model year Complete Heavy-Duty 
Vehicles under the special provisions of Sec. 86.1801-01(c)(2) when it 
does not exceed XXX pounds in curb weight, XXX pounds in gross vehicle 
weight rating, and XXX square feet in frontal area.''
    (e) The manufacturer of any incomplete light-duty vehicle, light-
duty truck, or heavy-duty vehicle shall notify the purchaser of such 
vehicle of any curb weight, frontal area, or gross vehicle weight 
rating limitations affecting the emission certificate applicable to 
that vehicle. This notification shall be transmitted in a manner 
consistent with National Highway Safety Administration safety 
notification requirements published in 49 CFR part 568.
    (f) All light-duty vehicles, light-duty trucks, and complete heavy-
duty vehicles shall comply with SAE Recommended Practices J1877 
``Recommended Practice for Bar-Coded Vehicle Identification Number 
Label,'' (July 1994), and J1892 ``Recommended Practice for Bar-Coded 
Vehicle Emission Configuration Label (May 1988). SAE J1877 and J1892 
are incorporated by reference (see Sec. 86.1).
* * * * *
    45. Section 86.1809-01 is amended by revising paragraph (a), to 
read as follows:


Sec. 86.1809-01  Prohibition of defeat devices.

    (a) No new light-duty vehicle, light-duty truck, or complete heavy-
duty vehicle shall be equipped with a defeat device.
* * * * *
    46. A new Sec. 86.1810-04 is added to subpart S, to read as 
follows:


Sec. 86.1810-04  General standards; increase in emissions; unsafe 
conditions; waivers.

    This section applies to model year 2004 and later light-duty 
vehicles, light-duty trucks, and complete heavy-duty vehicles fueled by 
gasoline, diesel, methanol, natural gas and liquefied petroleum gas 
fuels. Multi-fueled vehicles (including dual-fueled and flexible-fueled 
vehicles) shall comply with all requirements established for each 
consumed fuel (or blend of fuels in the case of flexible fueled 
vehicles). The standards of this subpart apply to both certification 
and in-use vehicles unless otherwise indicated. Section 86.1810-04 
includes text that specifies requirements that differ from 
Sec. 86.1810-01. Where a paragraph in Sec. 86.1810-04 is identical and 
applicable to Sec. 86.1810-01, this may be indicated by specifying the 
corresponding paragraph and the statement ``[Reserved]. For guidance 
see Sec. 86.1810-01.''.
    (a) through (c) [Reserved] For guidance see Sec. 86.1810-01.
    (d) Crankcase emissions prohibited. No crankcase emissions shall be 
discharged into the ambient atmosphere from any 2004 and later model 
year light-duty vehicle, light-duty truck, or complete heavy-duty 
vehicle.
    (e) On-board diagnostics. All light-duty vehicles, light-duty 
trucks and complete heavy-duty vehicles must have an on-board 
diagnostic system as described in Sec. 86.1806-04.
    (f) through (i) [Reserved] For guidance see Sec. 86.1810-01.
    (j) Evaporative emissions general provisions. (1) The evaporative 
standards in Secs. 86.1811-01(d), 86.1812-01(d), 86.1813-01(d), 
86.1814-04(d), 86.1815-04(d) and 86.1816-04(d) apply equally to 
certification and in-use vehicles and trucks. The spitback standard 
also applies to newly assembled vehicles.
    (2) For certification testing only, manufacturers may conduct 
testing to quantify a level of nonfuel background emissions for an 
individual test vehicle. Such a demonstration must include a 
description of the source(s) of emissions and an estimated decay rate. 
The demonstrated level of nonfuel background emissions may be 
subtracted from evaporative emission test results from certification 
vehicles if approved in advance by the Administrator.
    (3) All fuel vapor generated in a gasoline-or methanol-fueled 
light-duty vehicle, light-duty truck, or complete heavy-duty vehicle 
during in-use operation shall be routed exclusively to the evaporative 
control system (e.g., either canister or engine purge.) The only 
exception to this requirement shall be for emergencies.
    (k) Refueling emissions general provisions. (1) Implementation 
schedules. Table S04-5 of this section gives the minimum percentage of 
a manufacturer's sales of the applicable model year's gasoline- and 
methanol-fueled Otto-cycle and petroleum-fueled and methanol-fueled 
diesel-cycle heavy light-duty trucks and complete heavy-duty vehicles 
which shall be tested under the applicable procedures in subpart B of 
this part, and shall not exceed the standards described in 
Secs. 86.1813-04(e), 86.1814-04(e), and

[[Page 58558]]

86.1816-04(e). Vehicles waived from the emission standards under the 
provisions of paragraphs (m) and (n) of this section shall not be 
counted in the calculation of the percentage of compliance. Either 
manufacturer sales or actual production intended for sale in the United 
States may be used to determine combined volume, at the manufacturers 
option. Table S04-5 follows:

  Table S04-5--Heavy Light-Duty Trucks and Complete Heavy-Duty Vehicles
------------------------------------------------------------------------
                         Model year                           Percentage
------------------------------------------------------------------------
2004.......................................................           40
2005.......................................................           80
2006.......................................................          100
------------------------------------------------------------------------

    (2) Determining sales percentages. Sales percentages for the 
purposes of determining compliance with the applicable refueling 
emission standards for heavy light-duty trucks and complete heavy-duty 
vehicles shall be based on total actual U.S. sales of heavy light-duty 
trucks and complete heavy-duty vehicles of the applicable model year by 
a manufacturer to a dealer, distributor, fleet operator, broker, or any 
other entity which comprises the point of first sale.
    (3) Refueling receptacle requirements. Refueling receptacles on 
natural gas-fueled light-duty vehicles, light-duty trucks, and complete 
heavy-duty vehicles shall comply with the receptacle provisions of the 
ANSI/AGA NGV1-1994 standard (as incorporated by reference in 
Sec. 86.1(b)(3)). This requirement is subject to the phase-in schedules 
in Tables S01-3 and S01-4 in Sec. 86.1810-01 (k)(1), and Table S04-5 in 
paragraph (k)(1) of this section.
    (l) Fuel dispensing spitback testing waiver. (1) Vehicles certified 
to the refueling emission standards set forth in Secs. 86.1811-01(e), 
86.1812-01(e), 86.1813-01(e), 86.1814-04(e), 86.1815-04(e), and 
86.1816-04(e) are not required to demonstrate compliance with the fuel 
dispensing spitback standard contained in that section provided that:
    (i) The manufacturer certifies that the vehicle inherently meets 
the fuel dispensing spitback standard as part of compliance with the 
refueling emission standard; and
    (ii) This certification is provided in writing and applies to the 
full useful life of the vehicle.
    (2) EPA retains the authority to require testing to enforce 
compliance and to prevent noncompliance with the fuel dispensing 
spitback standard.
    (m) Inherently low refueling emission testing waiver. 
    (1) Vehicles using fuels/fuel systems inherently low in refueling 
emissions are not required to conduct testing to demonstrate compliance 
with the refueling emission standards set forth in Secs. 86.1811-01(e), 
86.1812-01(e), 86.1813-01(e), 86.1814-04(e), and 86.1815-04(e), 
provided that:
    (i) This provision is only available for petroleum diesel fuel. It 
is only available if the Reid Vapor Pressure of in-use diesel fuel is 
equal to or less than 1 psi (7 kPa) and for diesel vehicles whose fuel 
tank temperatures do not exceed 130 deg.F (54 deg. C); and
    (ii) To certify using this provision the manufacturer must attest 
to the following evaluation: ``Due to the low vapor pressure of diesel 
fuel and the vehicle tank temperatures, hydrocarbon vapor 
concentrations are low and the vehicle meets the 0.20 grams/gallon 
refueling emission standard without a control system.''
    (2) The certification required in paragraph (m)(1)(ii) of this 
section must be provided in writing and must apply for the full useful 
life of the vehicle.
    (3) EPA reserves the authority to require testing to enforce 
compliance and to prevent noncompliance with the refueling emission 
standard.
    (n) Fixed liquid level gauge waiver. Liquefied petroleum gas-fueled 
vehicles which contain fixed liquid level gauges or other gauges or 
valves which can be opened to release fuel or fuel vapor during 
refueling, and which are being tested for refueling emissions, are not 
required to be tested with such gauges or valves open, as outlined in 
Sec. 86.157-98(d)(2), provided the manufacturer can demonstrate, to the 
satisfaction of the Administrator, that such gauges or valves would not 
be opened during refueling in-use due to inaccessibility or other 
design features that would prevent or make it very unlikely that such 
gauges or valves could be opened.
    47. Section 86.1811-01 is amended by adding paragraph (h), to read 
as follows:


Sec. 86.1811-01  Emission standards for light-duty vehicles.

* * * * *
    (g) Manufacturers may request to group light-duty vehicles into the 
same test group as vehicles subject to more stringent standards, so 
long as those light-duty vehicles meet the most stringent standards 
applicable to any vehicle within that test group, as provided at 
Sec. 86.1827(a)(5) and (d)(4).
    48. Section 86.1812-01 is amended by adding paragraph (h), to read 
as follows:


Sec. 86.1812-01  Emission standards for light-duty trucks 1.

* * * * *
    (h) Manufacturers may request to group light-duty truck 1's into 
the same test group as vehicles subject to more stringent standards, so 
long as those light-duty truck 1's meet the most stringent standards 
applicable to any vehicle within that test group, as provided at 
Sec. 86.1827(a)(5) and(d)(4).
    49. Section 86.1813-01 is amended by adding paragraph (h), to read 
as follows:


Sec. 86.1813-01  Emission standards for light-duty trucks 2.

* * * * *
    (h) Manufacturers may request to group light-duty truck 2's into 
the same test group as vehicles subject to more stringent standards, so 
long as those light-duty truck 2's meet the most stringent standards 
applicable to any vehicle within that test group, as provided at 
Sec. 86.1827(a)(5) and (d)(4).
    50. Section 86.1814-01 is amended by adding paragraph (h), to read 
as follows:


Sec. 86.1814-01  Emission standards for light-duty trucks 3.

* * * * *
    (h) Manufacturers may request to group light-duty truck 3's into 
the same test group as vehicles subject to more stringent standards, so 
long as those light-duty truck 3's meet the most stringent standards 
applicable to any vehicle within that test group, as provided at 
Sec. 86.1827(a)(5) and (d)(4).
    51. Section 86.1814-02 is amended by adding paragraph (h), to read 
as follows:


Sec. 86.1814-02  Emission standards for light-duty trucks 3.

* * * * *
    (h) Manufacturers may request to group light-duty truck 3's into 
the same test group as vehicles subject to more stringent standards, so 
long as those light-duty truck 3's meet the most stringent standards 
applicable to any vehicle within that test group, as provided at 
Sec. 86.1827(a)(5) and (d)(4).
    52. Section 86.1815-01 is amended by adding paragraph (h), to read 
as follows:


Sec. 86.1815-01  Emission standards for light-duty trucks 4.

* * * * *
    (h) Manufacturers may request to group light-duty truck 4's into 
the same test group as vehicles subject to more stringent standards, so 
long as those light-duty truck 4's meet the most stringent standards 
applicable to any vehicle within that test group, as provided at 
Sec. 86.1827(a)(5) and (d)(4).
    53. Section 86.1815-02 is amended by adding paragraph (h), to read 
as follows:

[[Page 58559]]

Sec. 86.1815-02  Emission standards for light-duty trucks 4.

* * * * *
    (h) Manufacturers may request to group light-duty truck 4's into 
the same test group as vehicles subject to more stringent standards, so 
long as those light-duty truck 4's meet the most stringent standards 
applicable to any vehicle within that test group, as provided at 
Sec. 86.1827(a)(5) and (d)(4).
    54. A new section 86.1816-04 is added to subpart S, to read as 
follows:


Sec. 86.1816-04  Emission standards for complete heavy-duty vehicles

    This section applies to 2004 and later model year complete heavy-
duty vehicles fueled by gasoline, methanol, natural gas and liquefied 
petroleum gas fuels except as noted. This section also applies to 2000 
and later model year complete heavy duty vehicles participating in the 
early banking provisions of the averaging, trading and banking program 
as specified in Sec. 86.1817-04(n). Multi-fueled vehicles shall comply 
with all requirements established for each consumed fuel. For methanol 
fueled vehicles, references in this section to hydrocarbons or total 
hydrocarbons shall mean total hydrocarbon equivalents and references to 
non-methane hydrocarbons shall mean non-methane hydrocarbon 
equivalents.
    (a) Exhaust emission standards. (1) Exhaust emissions from 2004 and 
later model year complete heavy-duty vehicles at and above 8,500 pounds 
Gross Vehicle Weight Rating but equal to or less than 10,000 Gross 
Vehicle Weight Rating pounds shall not exceed the following standards 
at full useful life:
    (i) [Reserved]
    (ii) Non-methane organic gas. 0.280 grams per mile; this 
requirement may be satisfied by measurement of non-methane hydrocarbons 
or total hydrocarbons, at the manufacturer's option.
    (iii) Carbon monoxide. 7.3 grams per mile.
    (iv) Oxides of nitrogen. 0.9 grams per mile.
    (v) [Reserved]
    (2) Exhaust emissions from 2004 and later model year complete 
heavy-duty vehicles above 10,000 pounds Gross Vehicle Weight Rating but 
less than 14,000 pounds Gross Vehicle Weight Rating shall not exceed 
the following standards at full useful life:
    (i) [Reserved]
    (ii) Non-methane organic gas. 0.330 grams per mile; this 
requirement may be satisfied by measurement of non-methane hydrocarbons 
or total hydrocarbons, at the manufacturer's option.
    (iii) Carbon monoxide. 8.1 grams per mile.
    (iv) Oxides of nitrogen. 1.0 grams per mile.
    (v) [Reserved]
    (b) [Reserved]
    (c) [Reserved]
    (d) Evaporative emissions. Evaporative hydrocarbon emissions from 
gasoline-fueled, natural gas-fueled, liquefied petroleum gas-fueled, 
and methanol-fueled complete heavy-duty vehicles shall not exceed the 
following standards. The standards apply equally to certification and 
in-use vehicles. The spitback standard also applies to newly assembled 
vehicles.
    (1) For the full three-diurnal test sequence, diurnal plus hot soak 
measurements: 3.0 grams per test.
    (2) Gasoline and methanol fuel only. For the supplemental two-
diurnal test sequence, diurnal plus hot soak measurements: 3.5 grams 
per test.
    (3) Gasoline and methanol fuel only. Running loss test: 0.05 grams 
per mile.
    (4) Gasoline and methanol fuel only. Fuel dispensing spitback test: 
1.0 grams per test.
    (e) Refueling emissions. (1) Refueling emissions from complete 
heavy-duty vehicles equal to or less than 10,000 pounds Gross Vehicle 
Weight Rating shall be phased in, in accordance with the schedule in 
Table S04-5 in Sec. 1810-04 not to exceed the following emission 
standards:
    (i) For gasoline-fueled and methanol-fueled vehicles: 0.20 grams 
hydrocarbon per gallon (0.053 gram per liter) of fuel dispensed.
    (ii) For liquefied petroleum gas-fueled vehicles: 0.15 grams 
hydrocarbon per gallon (0.04 gram per liter) of fuel dispensed.
    (2) The provisions of Sec. 86.1816-04(e) do not apply to incomplete 
heavy-duty vehicles optionally certified to complete heavy duty vehicle 
standards under the provisions of Sec. 86.1801-01(c)(2).
    (f) [Reserved]
    (g) Idle exhaust emission standards, complete heavy-duty vehicles. 
Exhaust emissions of carbon monoxide from 2004 and later model year 
gasoline, methanol, natural gas- and liquefied petroleum gas-fueled 
complete heavy-duty vehicles shall not exceed 0.50 percent of exhaust 
gas flow at curb idle for a useful life of 11 years or 120,000 miles, 
whichever occurs first.
    (h) Manufacturers may request to group complete heavy-duty vehicles 
into the same test group as vehicles subject to more stringent 
standards, so long as those complete heavy-duty vehicles meet the most 
stringent standards applicable to any vehicle within that test group, 
as provided at Sec. 86.1827(a)(5) and (d)(4).
    55. A new section 86.1817-04 is added to subpart S, to read as 
follows:


Sec. 86.1817-04  Complete heavy-duty vehicle averaging, trading, and 
banking program.

    (a)(1) Complete heavy-duty vehicles eligible for the NOX 
averaging, trading and banking program are described in the applicable 
emission standards section of this subpart. All heavy-duty vehicles 
which include an engine labeled for use in clean-fuel vehicles as 
specified in 40 CFR part 88 are not eligible for this program. 
Participation in this averaging, trading, and banking program is 
voluntary.
    (2)(i) Test groups with a family emission limit (FEL) as defined in 
Sec. 86.1803-01 exceeding the applicable standard shall obtain emission 
credits as defined in Sec. 86.1803-01 in a mass amount sufficient to 
address the shortfall. Credits may be obtained from averaging, trading, 
or banking, as defined in Sec. 86.1803-01 within the averaging set 
restrictions described in paragraph (d) of this section.
    (ii) Test groups with an FEL below the applicable standard will 
have emission credits available to average, trade, bank or a 
combination thereof. Credits may not be used for averaging or trading 
to offset emissions that exceed an FEL. Credits may not be used to 
remedy an in-use nonconformity determined by a Selective Enforcement 
Audit or by recall testing. However, credits may be used to allow 
subsequent production of vehicles for the test group in question if the 
manufacturer elects to recertify to a higher FEL.
    (b) Participation in the NOX averaging, trading, and 
banking program shall be done as follows:
    (1) During certification, the manufacturer shall:
    (i) Declare its intent to include specific test groups in the 
averaging, trading and banking program.
    (ii) Declare an FEL for each test group participating in the 
program.
    (A) The FEL must be to the same level of significant digits as the 
emission standard (one-hundredth of a gram per mile for NOX 
emissions).
    (B) In no case may the FEL exceed the upper limit prescribed in the 
section concerning the applicable complete heavy-duty vehicle chassis-
based NOX emission standard.
    (iii) Calculate the projected NOX emission credits 
(positive or negative) as defined in Sec. 86.1803-01 based on quarterly 
production projections for each participating test group, using the 
applicable equation in paragraph (c) of

[[Page 58560]]

this section and the applicable factors for the specific test group.
    (iv)(A) Determine and state the source of the needed credits 
according to quarterly projected production for test groups requiring 
credits for certification.
    (B) State where the quarterly projected credits will be applied for 
test groups generating credits.
    (C) Emission credits as defined in Sec. 86.1803-01 may be obtained 
from or applied to only test groups within the same averaging set as 
defined in Sec. 86.1803-01. Emission credits available for averaging, 
trading, or banking, may be applied exclusively to a given test group, 
or designated as reserved credits as defined in Sec. 86.1803-01.
    (2) Based on this information, each manufacturer's certification 
application must demonstrate:
    (i) That at the end of model year production, each test group has a 
net emissions credit balance of zero or more using the methodology in 
paragraph (c) of this section with any credits obtained from averaging, 
trading or banking.
    (ii) The source of the credits to be used to comply with the 
emission standard if the FEL exceeds the standard, or where credits 
will be applied if the FEL is less than the emission standard. In cases 
where credits are being obtained, each test group involved must state 
specifically the source (manufacturer/test group) of the credits being 
used. In cases where credits are being generated/supplied, each test 
group involved must state specifically the designated use 
(manufacturer/test group or reserved) of the credits involved. All such 
reports shall include all credits involved in averaging, trading or 
banking.
    (3) During the model year, manufacturers must:
    (i) Monitor projected versus actual production to be certain that 
compliance with the emission standards is achieved at the end of the 
model year.
    (ii) Provide the end-of-year reports required under paragraph (i) 
of this section.
    (iii) For manufacturers participating in emission credit trading, 
maintain the quarterly records required under paragraph (l) of this 
section.
    (4) Projected credits based on information supplied in the 
certification application may be used to obtain a certificate of 
conformity. However, any such credits may be revoked based on review of 
end-of-model year reports, follow-up audits, and any other compliance 
measures deemed appropriate by the Administrator.
    (5) Compliance under averaging, banking, and trading will be 
determined at the end of the model year. Test groups without an 
adequate amount of NOX emission credits will violate the 
conditions of the certificate of conformity. The certificates of 
conformity may be voided ab initio for test groups exceeding the 
emission standard.
    (6) If EPA or the manufacturer determines that a reporting error 
occurred on an end-of-year report previously submitted to EPA under 
this section, the manufacturer's credits and credit calculations will 
be recalculated. Erroneous positive credits will be void. Erroneous 
negative balances may be adjusted by EPA for retroactive use.
    (i) If EPA review of a manufacturer's end-of-year report indicates 
a credit shortfall, the manufacturer will be permitted to purchase the 
necessary credits to bring the credit balance for that test group to 
zero, at the ratio of 1.2 credits purchased for every credit needed to 
bring the balance to zero. If sufficient credits are not available to 
bring the credit balance for the test group in question to zero, EPA 
may void the certificate for that test group ab initio.
    (ii) If within 180 days of receipt of the manufacturer's end-of-
year report, EPA review determines a reporting error in the 
manufacturer's favor (i.e. resulting in a positive credit balance) or 
if the manufacturer discovers such an error within 180 days of EPA 
receipt of the end-of-year report, the credits will be restored for use 
by the manufacturer.
    (c) For each participating test group, NOX emission 
credits (positive or negative) are to be calculated according to one of 
the following equations and rounded, in accordance with ASTM E29-93a, 
to the nearest one-tenth of a Megagram (MG). Consistent units are to be 
used throughout the equation.
    (1) For determining credit need for all test groups and credit 
availability for test groups generating credits for averaging only:

Emission credits=(Std-FEL)  x (UL) x (Production) x (10-6)

    (2) For determining credit availability for test groups generating 
credits for trading or banking:

Emission credits=(Std-FEL)  x (UL) x (Production) x (10-6) 
(Discount)

    (3) For purposes of the equations in paragraphs (c)(1) and (c)(2) 
of this section:

Std=the current and applicable complete heavy-duty vehicle 
NOX emission standard in grams per mile or grams per 
kilometer for model year 2004 and later vehicles.
Std=0.9 grams per mile for model year 2001 through 2003 heavy-duty 
vehicles at and above 8,500 pounds Gross Vehicle Weight Rating but 
equal to or less than 10,000 Gross Vehicle Weight Rating pounds and 1.0 
grams per mile for heavy-duty vehicles above 10,000 pounds Gross 
Vehicle Weight Rating but less than 14,000 pounds Gross Vehicle Weight 
Rating.
FEL=the NOX family emission limit for the test group in 
grams per mile or grams per kilometer.
UL=the useful life, or alternative life as described in paragraph (c) 
of Sec. 86.1805-01, for the given test group in miles or kilometers.
Production=the number of vehicles produced for U.S. sales within the 
given test group during the model year. Quarterly production 
projections are used for initial certification. Actual production is 
used for end-of-year compliance determination.
Discount=a one-time discount applied to all credits to be banked or 
traded within the model year generated. Except as otherwise allowed in 
paragraph (m) of this section, the discount applied here is 0.9. Banked 
credits traded in a subsequent model year will not be subject to an 
additional discount. Banked credits used in a subsequent model year's 
averaging program will not have the discount restored.

    (d) Averaging sets. The averaging and trading of NOX 
emission credits will be allowed between all test groups of complete 
heavy-duty vehicle excluding those vehicles produced for sale in 
California. Averaging, banking, and trading are not applicable to 
vehicles sold in California.
    (e) Banking of NOX emission credits. (1) Credit 
deposits. (i) NOX emission credits may be banked from test 
groups produced in any model year.
    (ii) Manufacturers may bank credits only after the end of the model 
year and after actual credits have been reported to EPA in the end-of-
year report. During the model year and before submittal of the end-of-
year report, credits originally designated in the certification process 
for banking will be considered reserved and may be redesignated for 
trading or averaging.
    (2) Credit withdrawals. (i) NOX credits generated in 
2004 and later model years do not expire.
    (ii) Manufacturers withdrawing banked emission credits shall 
indicate so during certification and in their credit reports, as 
described in paragraph (i) of this section.
    (3) Use of banked emission credits. The use of banked credits shall 
be

[[Page 58561]]

within the averaging set and geographic restrictions described in 
paragraph (d) of this section, and only for the following purposes:
    (i) Banked credits may be used in averaging, or in trading, or in 
any combination thereof, during the certification period. Credits 
declared for banking from the previous model year but not reported to 
EPA may also be used. However, if EPA finds that the reported credits 
can not be proven, they will be revoked and unavailable for use.
    (ii) Banked credits may not be used for averaging and trading to 
offset emissions that exceed an FEL. Banked credits may not be used to 
remedy an in-use nonconformity determined by a Selective Enforcement 
Audit or by recall testing. However, banked credits may be used for 
subsequent production of the test group if the manufacturer elects to 
recertify to a higher FEL.
    (f) In the event of a negative credit balance in a trading 
situation, both the buyer and the seller would be liable.
    (g) Certification fuel used for credit generation must be of a type 
that is both available in use and expected to be used by the vehicle 
purchaser. Therefore, upon request by the Administrator, the vehicle 
manufacturer must provide information acceptable to the Administrator 
that the designated fuel is readily available commercially and would be 
used in customer service.
    (h) Credit apportionment. At the manufacturers option, credits 
generated from complete heavy-duty vehicles under the provisions 
described in this section may be sold to or otherwise provided to the 
another party for use in programs other than the averaging, trading and 
banking program described in this section.
    (1) The manufacturer shall pre-identify two emission levels per 
test group for the purposes of credit apportionment. One emission level 
shall be the FEL and the other shall be the level of the standard that 
the test group is required to certify to under Sec. 86.1816-04. For 
each test group, the manufacturer may report vehicle sales in two 
categories, ``ABT-only credits'' and ``nonmanufacturer-owned credits''.
    (i) For vehicle sales reported as ``ABT-only credits'', the credits 
generated must be used solely in the averaging, trading and banking 
program described in this section.
    (ii) The vehicle manufacturer may declare a portion of vehicle 
sales ``nonmanufacturer-owned credits'' and this portion of the credits 
generated between the standard and the FEL, based on the calculation in 
paragraph (c)(1) of this section, would belong to the vehicle 
purchaser. The manufacturer may not generate any credits for the 
vehicle sales reported as ``nonmanufacturer-owned credits'' for this 
averaging, trading and banking program. Vehicles reported as 
``nonmanufacturer-owned credits'' shall comply with the FEL and the 
requirements of this averaging, trading and banking program in all 
other respects.
    (2) Only manufacturer-owned credits reported as ``ABT-only 
credits'' shall be used in the averaging, trading, and banking 
provisions described in this section.
    (3) Credits shall not be double-counted. Credits used in this 
averaging, trading and banking program may not be provided to a vehicle 
purchaser for use in another program.
    (4) Manufacturers shall determine and state the number of vehicles 
sold as ``ABT-only credits'' and ``nonmanufacturer-owned credits'' in 
the end-of-model year reports required under paragraph (i) of this 
section.
    (i) Manufacturers participating in the emissions averaging, trading 
and banking program, shall submit for each participating test group the 
items listed in paragraphs (i)(1) through (3) of this section.
    (1) Application for certification. (i) The application for 
certification will include a statement that the vehicles for which 
certification is requested will not, to the best of the manufacturer's 
belief, when included in the averaging, trading and banking program, 
cause the applicable NOX emissions standard to be exceeded.
    (ii) The application for certification will also include 
identification of the section of this subpart under which the test 
group is participating in the averaging, trading and banking program 
(e.g., Sec. 86.1817-04), the type (NOX), and the projected 
number of credits generated/needed for this test group, the applicable 
averaging set, the projected U.S. production volumes (excluding 
vehicles produced for sale in California), by quarter, and the values 
required to calculate credits as given in the applicable averaging, 
trading and banking section. Manufacturers shall also submit how and 
where credit surpluses are to be dispersed and how and through what 
means credit deficits are to be met, as explained in the applicable 
averaging, trading and banking section. The application must project 
that each test group will be in compliance with the applicable emission 
standards based on the vehicle mass emissions and credits from 
averaging, trading and banking.
    (2) [Reserved].
    (3) End-of-year report. The manufacturer shall submit end-of-year 
reports for each test group participating in the averaging, trading and 
banking program, as described in paragraphs (i)(3)(i) through (iv) of 
this section.
    (i) These reports shall be submitted within 90 days of the end of 
the model year to: Director, Engine Programs and Compliance Division 
(6405J), U.S. Environmental Protection Agency, 401 M Street, SW, 
Washington, DC 20460.
    (ii) These reports shall indicate the test group, the averaging 
set, the actual U.S. production volume (excluding vehicles produced for 
sale in California), the values required to calculate credits as given 
in the applicable averaging, trading and banking section, and the 
resulting type and number of credits generated/required. Manufacturers 
shall also submit how and where credit surpluses were dispersed (or are 
to be banked) and how and through what means credit deficits were met. 
Copies of contracts related to credit trading must also be included or 
supplied by the broker if applicable. The report shall also include a 
calculation of credit balances to show that net mass emissions balances 
are within those allowed by the emission standards (equal to or greater 
than a zero credit balance). Any credit discount factor described in 
the applicable averaging, trading and banking section must be included 
as required.
    (iii) The production counts for end-of-year reports shall be based 
on the location of the first point of retail sale (e.g., customer, 
dealer, secondary manufacturer) by the manufacturer.
    (iv) Errors discovered by EPA or the manufacturer in the end-of-
year report, including changes in the production counts, may be 
corrected up to 180 days subsequent to submission of the end-of-year 
report. Errors discovered by EPA after 180 days shall be corrected if 
credits are reduced. Errors in the manufacturer's favor will not be 
corrected if discovered after the 180 day correction period allowed.
    (j) Failure by a manufacturer participating in the averaging, 
trading and banking program to submit any quarterly or end-of-year 
report (as applicable) in the specified time for all vehicles that are 
part of an averaging set is a violation of section 203(a)(1) of the 
Clean Air Act (42 U.S.C. 7522(a)(1)) for such vehicles.
    (k) Failure by a manufacturer generating credits for deposit only 
in the complete heavy-duty vehicle banking program to submit their end-
of-year reports in the applicable specified time period (i.e., 90 days 
after the end of the model year) shall result in the credits

[[Page 58562]]

not being available for use until such reports are received and 
reviewed by EPA. Use of projected credits pending EPA review will not 
be permitted in these circumstances.
    (l) Any manufacturer producing a test group participating in 
trading using reserved credits, shall maintain the following records on 
a quarterly basis for each test group in the trading subclass:

(1) The test group;
(2) The averaging set;
(3) The actual quarterly and cumulative U.S. production volumes 
excluding vehicles produced for sale in California;
(4) The values required to calculate credits as given in paragraph (c) 
of this section;
(5) The resulting type and number of credits generated/required;
(6) How and where credit surpluses are dispersed; and
(7) How and through what means credit deficits are met.

    (m) Additional flexibility for complete heavy-duty vehicles. If a 
complete heavy-duty vehicle has a NOX FEL of 0.6 grams per 
mile or lower, a discount of 1.0 may be used in the trading and banking 
credits calculation for NOX described in paragraph (c)(2) of 
this section.
    (n) Early banking for complete heavy-duty vehicles. Provisions set 
forth in paragraphs (a) through (m) of this section apply except as 
specifically stated otherwise in paragraph (n) of this section.
    (1) To be eligible for the early banking program described in this 
paragraph, the following must apply:
    (i) Credits are generated from complete heavy-duty vehicles.
    (ii) During certification, the manufacturer shall declare its 
intent to include specific test groups in the early banking program 
described in this paragraph.
    (2) Credit generation and use. (i) Credits shall only be generated 
by model year 2000 through 2003 test groups.
    (ii) Credits may only be used for 2004 and later model year 
complete heavy-duty vehicles and shall be subject to all discounting, 
credit life, and all other provisions contained in paragraphs (a) 
through (m) of this section.
    56. Section 86.1821-01 is amended by revising the first sentence of 
paragraph (a), and the introductory text of paragraph (b), to read as 
follows:


Sec. 86.1821-01  Evaporative/refueling family determination.

    (a) The gasoline-, methanol-, liquefied petroleum gas-, and natural 
gas-fueled light-duty vehicles, light-duty trucks, and complete heavy-
duty vehicles described in a certification application will be divided 
into groupings which are expected to have similar evaporative and/or 
refueling emission characteristics (as applicable) throughout their 
useful life. * * *
    (b) For gasoline-fueled or methanol-fueled light-duty vehicles, 
light-duty trucks, and complete heavy-duty vehicles to be classed in 
the same evaporative/refueling family, vehicles must be similar with 
respect to the items listed in paragraphs (b)(1) through (9) of this 
section.
* * * * *
    57. Section 86.1823-01 is amended by revising the introductory 
text, paragraph (c)(2) introductory text, and the first sentence of 
paragraph (h), to read as follows:


Sec. 86.1823-01  Durability demonstration procedures for exhaust 
emissions.

    This section applies to light-duty vehicles, light-duty trucks, 
complete heavy-duty vehicles, and heavy-duty vehicles certified under 
the provisions of Sec. 86.1801-01(c). Eligible small volume 
manufacturers or small volume test groups may optionally meet the 
requirements of Secs. 86.1838-01 and 86.1826-01 in lieu of the 
requirements of this section. For model years 2001, 2002, and 2003 all 
manufacturers may elect to meet the provisions of paragraph (c)(2) of 
this section in lieu of these requirements for light-duty vehicles or 
light-duty trucks.
* * * * *
    (c) * * *
    (2) For the 2001, 2002, and 2003 model years, for light-duty 
vehicles and light-duty trucks the manufacturer may carry over exhaust 
emission DF's previously generated under the Standard AMA Durability 
Program described in Sec. 86.094-13(c), the Alternate Service 
Accumulation Durability Program described in Sec. 86.094-13(e) or the 
Standard Self-Approval Durability Program for light-duty trucks 
described in Sec. 86.094-13(f) in lieu of complying with the durability 
provisions of paragraph (a)(1) of this section.
* * * * *
    (h) The Administrator may withdraw approval to use a durability 
process or require modifications to a durability process based on the 
data collected under Secs. 86.1845-01, 86.1846-01, and 86.1847-01 or 
other information if the Administrator determines that the durability 
processes have not been shown to accurately predict emission levels or 
compliance with the standards (or FEL, as applicable) in use on 
candidate vehicles (provided the inaccuracy could result in a lack of 
compliance with the standards for a test group covered by this 
durability process). * * *
* * * * *
    58. Section 86.1824-01 is amended by revising the first sentence of 
the introductory text, redesignating paragraphs (d) through (f) as 
paragraphs (e) through (g), and by adding new paragraph (d), to read as 
follows:


Sec. 86.1824-01  Durability demonstration procedures for evaporative 
emissions.

    This section applies to gasoline-, methanol-, liquefied petroleum 
gas-, and natural gas-fueled light-duty vehicles, light-duty trucks, 
complete heavy-duty vehicles, and heavy-duty vehicles certified under 
the provisions of Sec. 86.1801-01(c). * * *
* * * * *
    (d) The durability process described in paragraph (a) of this 
section must be described in the application for certification under 
the provisions of Sec. 86.1844-01.
* * * * *
    59. Section 86.1825-01 is amended by revising the first two 
sentences of introductory text to read as follows:


Sec. 86.1825-01  Durability demonstration procedures for refueling 
emissions.

    This section applies to light-duty vehicles, light-duty trucks, and 
complete heavy-duty vehicles, and heavy-duty vehicles which are 
certified under light-duty rules as allowed under the provisions of 
Sec. 86.1801-01(c) which are subject to refueling loss emission 
compliance. Refer to the provisions of Secs. 86.1811-01, 86.1812-01, 
86.1813-01, 86.1814-04, 86.1815-04, and 86.1816-04 to determine 
applicability of the refueling standards to different classes of 
vehicles for various model years. * * *
* * * * *
    60. Section 86.1826-01 is amended by revising paragraphs (b)(2) 
introductory text and (b)(3) introductory text, to read as follows:


Sec. 86.1826-01  Assigned deterioration factors for small volume 
manufacturers and small volume test groups.

* * * * *
    (b) * *  *
    (2) Manufacturers with aggregated sales from and including 301 
through 14,999 motor vehicles and motor vehicle engines per year 
(determined under the provisions of Sec. 86.1838-01(b)) certifying 
vehicles equipped with

[[Page 58563]]

proven emission control systems shall conform to the following 
provisions:
* * * * *
    (3) Manufacturers with aggregated sales from 301 through 14,999 
motor vehicles and motor vehicle engines per year (determined under the 
provisions of Sec. 86.1838-01(b)) certifying vehicles equipped with 
unproven emission control systems shall conform to the following 
provisions:
* * * * *
    61. Section 86.1827-01 is amended by revising paragraph (a)(5), 
removing ``and'' at the end of paragraph (d)(2), removing the period at 
the end of paragraph (d)(3) and adding ``; and'' in its place, and 
adding paragraph (d)(4), to read as follows:


Sec. 86.1827-01  Test group determination.

* * * * *
    (a) * * *
    (5) Subject to the same emission standards, except that a 
manufacturer may request to group vehicles into the same test group as 
vehicles subject to more stringent standards, so long as those all the 
vehicles within the test group are certified to the most stringent 
standards applicable to any vehicle within that test group. Light-duty 
trucks which are subject to the same emission standards as light-duty 
vehicles with the exception of the light-duty truck idle CO standard 
and/or total HC standard may be included in the same test group.
* * * * *
    (d) * * *
    (4) A statement that all vehicles within a test group are certified 
to the most stringent standards applicable to any vehicle within that 
test group.
    62. Section 86.1829-01 is amended by revising paragraphs 
(b)(1)(ii)(B), (b)(2)(ii)(B), and (b)(5), to read as follows:


Sec. 86.1829-01  Durability and emission testing requirements; waivers.

* * * * *
    (b) * * *
    (1) * * *
    (ii) * * *
    (B) In lieu of testing vehicles according to the provisions of 
paragraph (b)(1)(ii)(A) of this section, a manufacturer may provide a 
statement in its application for certification that, based on the 
manufacturer's engineering evaluation of appropriate high-altitude 
emission testing, all light-duty vehicles, light-duty trucks, and 
complete heavy-duty vehicles comply with the emission standards at high 
altitude.
* * * * *
    (2) * * *
    (ii) * * *
    (B) In lieu of testing vehicles according to the provisions of 
paragraph (b)(2)(ii)(A) of this section, a manufacturer may provide a 
statement in its application for certification that, based on the 
manufacturer's engineering evaluation of such high-altitude emission 
testing as the manufacturer deems appropriate, all light-duty vehicles, 
light-duty trucks, and complete heavy-duty vehicles comply with the 
emission standards at high altitude.
* * * * *
    (5) Idle CO Testing. To determine idle CO emission compliance for 
light-duty trucks and complete heavy-duty vehicles, the manufacturer 
shall follow one of the following two procedures:
    (i) For test groups containing light-duty trucks and complete 
heavy-duty vehicles, each EDV shall be tested in accordance with the 
idle CO testing procedures of subpart B of this Part; or
    (ii) In lieu of testing light trucks and complete heavy-duty 
vehicles for idle CO emissions, a manufacturer may provide a statement 
in its application for certification that, based on the manufacturer's 
engineering evaluation of such idle CO testing as the manufacturer 
deems appropriate, all light-duty trucks and complete heavy-duty 
vehicles comply with the idle CO emission standards.
* * * * *
    63. Section 86.1834-01 is amended by redesignating paragraphs 
(b)(3)(i), (b)(5) and (b)(6) as paragraphs (b)(3)(i)(A), (b)(6) and 
(b)(7), respectively, revising paragraphs (b)(3) introductory text, 
(b)(3)(ii) introductory text, (b)(3)(iii), (b)(3)(iv), the first 
sentence of newly redesignated paragraph (b)(6)(iii), the seventh 
sentence of newly redesignated paragraph (b)(7)(ii), the first sentence 
of newly redesignated paragraph (b)(7)(iii), and the heading of 
paragraph (d), adding paragraphs (b)(3)(i)(B), (b)(3)(v), (b)(3)(vi), 
and (b)(6)(i)(H), and adding and reserving paragraph (b)(5), to read as 
follows:


Sec. 86.1834-01  Allowable maintenance.

* * * * *
    (b) * * *
    (3) Emission-related maintenance in addition to, or at shorter 
intervals than, that listed in paragraphs (b)(3)(i) through (vi) of 
this section will not be accepted as technologically necessary, except 
as provided in paragraph (b)(7) of this section.
    (i) * * *
    (B) The cleaning or replacement of complete heavy-duty vehicle 
spark plugs shall occur at 25,000 miles (or 750 hours) of use and at 
30,000-mile (or 750 hour) intervals thereafter, for vehicles certified 
for use with unleaded fuel only.
    (ii) For light-duty vehicles and light-duty trucks, the adjustment, 
cleaning, repair, or replacement of the following items shall occur at 
50,000 miles of use and at 50,000-mile intervals thereafter:
* * * * *
    (iii) For complete heavy-duty vehicles, the adjustment, cleaning, 
repair, or replacement of the following items shall occur at 50,000 
miles (or 1,500 hours) of use and at 50,000-mile (1,500 hour) intervals 
thereafter:

    (A) Positive crankcase ventilation valve.
    (B) Emission-related hoses and tubes.
    (C) Ignition wires.
    (D) Idle mixture.
    (E) Exhaust gas recirculation system related filters and coolers.

    (iv) For light-duty trucks, light-duty vehicles, and complete 
heavy-duty vehicles, the adjustment, cleaning, repair, or replacement 
of the oxygen sensor shall occur at 80,000 miles (or 2,400 hours) of 
use and at 80,000-mile (or 2,400-hour) intervals thereafter.
    (v) For light-duty trucks and light-duty vehicles, the adjustment, 
cleaning, repair, or replacement of the following items shall occur at 
100,000 miles of use and at 100,000-mile intervals thereafter:

    (A) Catalytic converter.
    (B) Air injection system components.
    (C) Fuel injectors.
    (D) Electronic engine control unit and its associated sensors 
(except oxygen sensor) and actuators.
    (E) Evaporative and/or refueling emission canister(s).
    (F) Turbochargers.
    (G) Carburetors.
    (H) Superchargers.
    (I) Exhaust gas recirculation system including all related filters 
and control valves.

    (vi) For complete heavy-duty vehicles, the adjustment, cleaning, 
repair, or replacement of the following items shall occur at 100,000 
miles (or 3,000 hours) of use and at 100,000-mile (or 3,000 hour) 
intervals thereafter:

    (A) Catalytic converter.
    (B) Air injection system components.
    (C) Fuel injectors.
    (D) Electronic engine control unit and its associated sensors 
(except oxygen sensor) and actuators.
    (E) Evaporative and/or refueling emission canister(s).
    (F) Turbochargers.
    (G) Carburetors.
    (H) Exhaust gas recirculation system (including all related control 
valves and tubing) except as otherwise provided in paragraph 
(b)(3)(iii)(E) of this section.
* * * * *

[[Page 58564]]

    (5) [Reserved]
    (6) * * *
    (i) * * *
    (H) Any other add-on emissions-related component (i.e., a component 
whose sole or primary purpose is to reduce emissions or whose failure 
will significantly degrade emissions control and whose function is not 
integral to the design and performance of the engine.)
    (iii) Visible signal systems used under paragraph (b)(6)(ii)(C) of 
this section are considered an element of design of the emission 
control system. * * *
    (7) * * *
    (ii) * * * For maintenance items established as emission-related, 
the Administrator will further designate the maintenance as critical if 
the component which receives the maintenance is a critical component 
under paragraph (b)(6) of this section. * * *
    (iii) Any manufacturer may request a hearing on the Administrator's 
determinations in this paragraph (b)(7). * * *
    (d) Unscheduled maintenance on durability data vehicles. * * *
* * * * *
    64. Section 86.1835-01 is amended by revising the third sentence of 
paragraph (a)(1)(i), paragraph (b)(1) introductory text, and paragraph 
(b)(3) introductory text, to read as follows:


Sec. 86.1835-01  Confirmatory certification testing.

    (a) * * *
    (1) * * *
    (i) * * * The Administrator, in making or specifying such 
adjustments, will consider the effect of the deviation from the 
manufacturer's recommended setting on emissions performance 
characteristics as well as the likelihood that similar settings will 
occur on in-use light-duty vehicles, light-duty trucks, or complete 
heavy-duty vehicles. * * *
* * * * *
    (b) * * * (1) If the Administrator determines not to conduct a 
confirmatory test under the provisions of paragraph (a) of this 
section, light-duty vehicle and light-duty truck manufacturers will 
conduct a confirmatory test at their facility after submitting the 
original test data to the Administrator whenever any of the conditions 
listed in paragraph (b)(1)(i) through (v) of this section exist, and 
complete heavy-duty vehicles manufacturers will conduct a confirmatory 
test at their facility after submitting the original test data to the 
Administrator whenever the conditions listed in paragraph (b)(1)(i) or 
(b)(1)(ii) of this section exist.
* * * * *
    (3) For light-duty vehicles, and light-duty trucks, the 
manufacturer shall conduct a retest of the FTP or highway test if the 
difference between the fuel economy of the confirmatory test and the 
original manufacturer's test equals or exceeds three percent (or such 
lower percentage to be applied consistently to all manufacturer 
conducted confirmatory testing as requested by the manufacturer and 
approved by the Administrator).
* * * * *
    65. Section 86.1840-01 is revised to read as follows:


Sec. 86.1840-01  Special test procedures.

    (a) The Administrator may, on the basis of written application by a 
manufacturer, prescribe test procedures, other than those set forth in 
this part, for any light-duty vehicle, light-duty truck, or complete 
heavy-duty vehicle which the Administrator determines is not 
susceptible to satisfactory testing by the procedures set forth in this 
part.
    (b) If the manufacturer does not submit a written application for 
use of special test procedures but the Administrator determines that a 
light-duty vehicle, light-duty truck, or complete heavy-duty vehicle is 
not susceptible to satisfactory testing by the procedures set forth in 
this part, the Administrator shall notify the manufacturer in writing 
and set forth the reasons for such rejection in accordance with the 
provisions of Sec. 86.1848(a)(2).
    66. Section 86.1844-01 is amended by revising the fourth sentence 
of paragraph (d)(12), the fourth sentence of paragraph (e)(3), and 
paragraph (g)(5), and adding paragraph (g)(14) to read as follows:


Sec. 86.1844-01  Information requirements: Application for 
certification and submittal of information upon request.

* * * * *
    (d) * * *
    (12) * * * The description shall include, but is not limited to, 
information such as model name, vehicle classification (light-duty 
vehicle, light-duty truck, or complete heavy-duty vehicle), sales area, 
engine displacement, engine code, transmission type, tire size and 
parameters necessary to conduct exhaust emission tests such as 
equivalent test weight, curb and gross vehicle weight, test horsepower 
(with and without air conditioning adjustment), coast down time, shift 
schedules, cooling fan configuration, etc. and evaporative tests such 
as canister working capacity, canister bed volume and fuel temperature 
profile. * * *
* * * * *
    (e) * * *
    (3) * * * The description shall include, but is not limited to, 
information such as model name, vehicle classification (light-duty 
vehicle, light-duty truck, or complete heavy-duty vehicle), sales area, 
engine displacement, engine code, transmission type, tire size and 
parameters necessary to conduct exhaust emission tests such as 
equivalent test weight, curb and gross vehicle weight, test horsepower 
(with and without air conditioning adjustment), coast down time, shift 
schedules, cooling fan configuration, etc and evaporative tests such as 
canister working capacity, canister bed volume and fuel temperature 
profile. * * *
* * * * *
    (g) * * *
    (5) Any information necessary to demonstrate that no defeat devices 
are present on any vehicles covered by a certificate including, but not 
limited to, a description of the technology employed to control CO 
emissions at intermediate temperatures, as applicable.
* * * * *
    (14) For complete heavy-duty vehicles only, all hardware (including 
scan tools) and documentation necessary for EPA to read and interpret 
(in engineering units if applicable) any information broadcast by an 
engine's on-board computers and electronic control modules which 
relates in anyway to emission control devices and auxiliary emission 
control devices. This requirement includes access by EPA to any 
proprietary code information which may be broadcast by an engine's on-
board computer and electronic control modules. Information which is 
confidential business information must be marked as such. Engineering 
units refers to the ability to read and interpret information in 
commonly understood engineering units, for example, engine speed in 
revolutions per minute or per second, injection timing parameters such 
as start of injection in degree's before top-dead center, fueling rates 
in cubic centimeters per stroke, vehicle speed in milers per hour or 
per kilometer.
* * * * *
    67. Section 86.1845-01 is amended by revising paragraph (a), to 
read as follows:


Sec. 86.1845-01  Manufacturer in-use verification testing requirements.

    (a) General requirements. A manufacturer light-duty vehicles, 
light-duty trucks, and complete heavy-duty

[[Page 58565]]

vehicles shall test, or cause to have tested a specified number of 
light-duty vehicles, light-duty trucks, and complete heavy-duty 
vehicles. Such testing shall be conducted in accordance with the 
provisions of this section. For purposes of this section, the term 
vehicle shall include light-duty vehicles, light-duty trucks, and 
complete heavy-duty vehicles.
* * * * *
    68. Section 86.1845-04 is amended by revising paragraph (a), to 
read as follows:


Sec. 86.1845-04  Manufacturer in-use verification testing requirements.

    (a) General requirements. A manufacturer light-duty vehicles, 
light-duty trucks, and complete heavy-duty vehicles shall test, or 
cause to have tested a specified number of light-duty vehicles, light-
duty trucks, and complete heavy-duty vehicles. Such testing shall be 
conducted in accordance with the provisions of this section. For 
purposes of this section, the term vehicle shall include light-duty 
vehicles, light-duty trucks, and complete heavy-duty vehicles.
* * * * *
    69. A new section 86.1846-07 is added to subpart S, to read as 
follows:


Sec. 86.1846-07  Manufacturer in-use confirmatory testing.

    (a) General requirements. A manufacturer of light-duty vehicles, 
light-duty trucks, and/or complete heavy-duty vehicles shall test, or 
cause testing to be conducted, under this section when the emission 
levels shown by a test group sample from testing under Sec. 86.1845-04 
exceeds the criteria specified in paragraph (b) of this section. The 
testing required under this section applies separately to each test 
group and at each test point (low and high mileage) that meets the 
specified criteria. The testing requirements apply separately for each 
model year, starting with model year 2006.
    (b) Criteria for additional testing. A manufacturer shall test a 
test group or a subset of a test group as described in paragraph (j) of 
this section when the results from testing conducted under 
Sec. 86.1845-04 show mean emissions for that test group of any 
pollutant(s) to be equal to or greater than 1.30 times the applicable 
in-use standard and a failure rate, among the test group vehicles, for 
the corresponding pollutant(s) of fifty percent or greater.
    (1) This requirement does not apply to Supplemental FTP testing 
conducted under Sec. 86.1845-04(b)(5)(i) or evaporative/refueling 
testing conducted under Sec. 86.1845-04. Testing conducted at high 
altitude under the requirements of Sec. 86.1845-04 will be included in 
determining if a test group meets the criteria triggering testing 
required under this section.
    (2) The vehicle tested under the requirements of Sec. 86.1845-
04(c)(2)(i) with a minimum odometer miles of 75% of useful life will 
not be included in determining if a test group meets the triggering 
criteria.
    (3) The SFTP composite emission levels shall include the IUVP FTP 
emissions, the IUVP US06 emissions, and the values from the SC03 Air 
Conditioning EDV certification test (without DFs applied). The 
calculations shall be made using the equations prescribed in 
Sec. 86.164-01. If more than one set of certification SC03 data exists 
(due to running change testing or other reasons), the manufacturer 
shall choose the SC03 result to use in the calculation from among those 
data sets using good engineering judgment.
    (c) Useful life. Vehicles tested under the provisions of this 
section must be within the useful life specified for the emission 
standards which were exceeded in the testing under Sec. 86.1845-04. 
Testing should be within the useful life specified, subject to sections 
207(c)(5) and (c)(6) of the Clean Air Act where applicable.
    (d) Number of test vehicles. A manufacturer must test a minimum of 
ten vehicles of the test group or Agency-designated subset. A 
manufacturer may, at the manufacturer's discretion, test more than ten 
vehicles under this paragraph for a specific test group or Agency-
designated subset. If a manufacturer chooses to test more than the 
required ten vehicles, all testing must be completed within the time 
designated in the testing completion requirements of paragraph (g) of 
this section. Any vehicles which are eliminated from the sample either 
prior to or subsequent to testing, or any vehicles for which test 
results are determined to be void, must be replaced in order that the 
final sample of vehicles for which test results acceptable to the 
Agency are available equals a minimum of ten vehicles. A manufacturer 
may cease testing with a sample of five vehicles if the results of the 
first five vehicles tested show mean emissions for each pollutant to be 
less than 75.0 percent of the applicable standard, with no vehicles 
exceeding the applicable standard for any pollutant.
    (e) Emission Testing. Each test vehicle of a test group or Agency-
designated subset shall be tested in accordance with the Federal Test 
Procedure and/or the Supplemental Federal Test Procedure (whichever of 
these tests performed under Sec. 86.1845-04 produces emission levels 
requiring testing under this section) as described in subpart B of this 
part, when such test vehicle is tested for compliance with applicable 
exhaust emission standards under this subpart.
    (f) Geographical limitations. (1) Test groups or Agency-designated 
subsets certified to 50-state standards: For low altitude testing no 
more than 50 percent of the test vehicles may be procured from 
California. The test vehicles procured from the 49 state area must be 
procured from a location with a heating degree day 30 year annual 
average equal to or greater than 4000.
    (2) Test groups or Agency-designated subsets certified to 49 state 
standards: For low-altitude testing all vehicles shall be procured from 
a location with a heating degree day 30 year annual average equal to or 
greater than 4000.
    (3) Vehicles procured for high altitude testing may be procured 
from any area provided that the vehicle's primary area of operation was 
above 4000 feet.
    (g) Testing. Testing required under this section must commence 
within three months of completion of the testing under Sec. 86.1845-04 
which triggered the confirmatory testing and must be completed within 
seven months of the completion of the testing which triggered the 
confirmatory testing. Any industry review of the results obtained under 
Sec. 86.1845-04 and any additional vehicle procurement and/or testing 
which takes place under the provisions of Sec. 86.1845-04 which the 
industry believes may affect the triggering of required confirmatory 
testing must take place within the three month period. The data and the 
manufacturers reasoning for reconsideration of the data must be 
provided to the Agency within the three month period.
    (h) Limit on manufacturer conducted testing. For each manufacturer, 
the maximum number of test group(s)(or Agency-designated subset(s))of 
each model year for which testing under this section shall be required 
is limited to 50 percent of the total number of test groups of each 
model year required to be tested by each manufacturer as prescribed in 
Sec. 86.1845-04 rounded to the next highest whole number where 
appropriate. For each manufacturer with only one test group under 
Sec. 86.1845-04, such manufacturer shall have a maximum potential 
testing requirement under this section of one test group (or Agency-
designated subset) per model year.
    (i) Prior to beginning in-use confirmatory testing the manufacturer 
must, after consultation with the Agency, submit a written plan

[[Page 58566]]

describing the details of the vehicle procurement, maintenance, and 
testing procedures (not otherwise specified by regulation) it intends 
to use.
    (j) Testing a subset. EPA may designate a subset of the test group 
based on transmission type for testing under this section in lieu of 
testing the entire test group when the results for the entire test 
group from testing conducted under Sec. 86.1845-04 show mean emissions 
and a failure rate which meet these criteria for additional testing.
    70. Section 86.1848-01 is amended by revising paragraphs (c)(4) and 
the first sentence of paragraph (e) introductory text to read as 
follows:


Sec. 86.1848-01  Certification.

* * * * *
    (c) * * *
    (4) For incomplete light-duty trucks and incomplete heavy-duty 
vehicles, a certificate covers only those new motor vehicles which, 
when completed by having the primary load-carrying device or container 
attached, conform to the maximum curb weight and frontal area 
limitations described in the application for certification as required 
in Sec. 86.1844-01.
* * * * *
    (e) A manufacturer of new light-duty vehicles, light-duty trucks, 
and complete heavy-duty vehicles must obtain a certificate of 
conformity covering such vehicles from the Administrator prior to 
selling, offering for sale, introducing into commerce, delivering for 
introduction into commerce, or importing into the United States the new 
vehicle. * * *
* * * * *
[FR Doc. 99-26795 Filed 10-28-99; 8:45 am]
BILLING CODE 6560-50-P