[Federal Register Volume 71, Number 10 (Tuesday, January 17, 2006)]
[Rules and Regulations]
[Pages 2810-2842]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-74]



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Part IV





Environmental Protection Agency





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40 CFR Part 86



Emission Durability Procedures and Component Durability Procedures for 
New Light-Duty Vehicles, Light-Duty Trucks and Heavy-Duty Vehicles; 
Final Rule and Proposed Rule

  Federal Register / Vol. 71, No. 10 / Tuesday, January 17, 2006 / 
Rules and Regulations  

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 86

[FRL-8019-2]
RIN 2060-AK76


Emission Durability Procedures for New Light-Duty Vehicles, 
Light-Duty Trucks and Heavy-Duty Vehicles

AGENCY: Environmental Protection Agency.

ACTION: Final Rule.

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SUMMARY: This final rulemaking contains procedures to be used by 
manufacturers of light-duty vehicles, light-duty trucks, and some 
heavy-duty vehicles to demonstrate, for purposes of emission 
certification, that new motor vehicles will comply with EPA emission 
standards throughout their useful lives. Today's action defines 
procedures to be used by manufacturers to demonstrate the expected rate 
of deterioration of the emission levels of their vehicles.

DATES: This rule is effective February 16, 2006. The information 
collection requirements of this rule have been approved by OMB and are 
effective February 16, 2006.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. OAR-2002-0079. All documents in the docket are listed in the 
EDOCKET index at http://www.epa.gov/edocket. Although listed in the 
index, some information is not publicly available, i.e., CBI or other 
information whose disclosure is restricted by statute. Certain other 
material, such as copyrighted material, is not placed on the Internet 
and will be publicly available only in hard copy form. Publicly 
available docket materials are available either electronically in 
EDOCKET or in hard copy at the Air Docket, EPA/DC, EPA West, Room B102, 
1301 Constitution Ave., NW., Washington, DC. The Public Reading Room is 
open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding 
legal holidays. The telephone number for the Public Reading Room is 
(202) 566-1744.

FOR FURTHER INFORMATION CONTACT: General Contact: Linda Hormes, Vehicle 
Programs and Compliance Division, U.S. EPA, 2000 Traverwood, Ann Arbor, 
Michigan 48105, telephone (734) 214-4502, E-mail: [email protected].
    Technical Contact: Linc Wehrly, Vehicle Programs and Compliance 
Division, U.S. EPA, 2000 Traverwood, Ann Arbor, Michigan 48105, 
telephone: (734) 214-4286, E-mail: [email protected].

SUPPLEMENTARY INFORMATION: 

I. Background
    A. Overview of certification process, CAP 2000 history
    B. Durability demonstration process history
    1. Durability demonstration methods used prior to the CAP 2000 
regulations
    2. Emission durability procedures under CAP 2000
    C. Ethyl petition to reconsider CAP 2000 rules
    D. Judicial review of the CAP 2000 rules
    E. Applicability of the NPRM preamble discussion
    F. Supplemental notice regarding component durability
II. Summary and Analysis of Comments
    A. The Durability Objective
    B. Evaluation of the certification durability procedures based 
on in-use emissions data
    C. Standard whole vehicle durability procedure
    1. Standard Road Cycle (SRC)
    2. Vehicle ballasting on SRC mileage accumulation
    3. Calculating the DF from mileage accumulation of 75% of full 
useful life mileage
    4. Testing required for DF calculation
    5. Use of an engine dynamometer to recreate the aging on the SRC
    D. Standard Bench Aging Procedure
    E. Catalyst time-at-temperature data measurement
    F. Customized/Alternative durability procedures
    1. Equivalency factors and alternative road cycles
    2. Bench durability aging
    3. Approval of customized/alternative durability procedures
    4. Experimentally determining a customized R-factor
    5. Alternative bench aging cycle content
    G. Component Durability
    H. Minor modifications to approved durability procedures
    I. Required notification to EPA that an approved durability 
procedure will be used for a particular durability group
    J. Public Availability of the equivalency factor and supporting 
data
    K. Carryover
    L. Evaporative Durability Procedures
    M. Starting model year for the rule
    N. Special provisions for new manufacturers
    O. Delete incorrect reference to intermediate useful life 
standards for the evaporative and refueling durability objective
III. What is EPA promulgating today?
    A. Standard whole vehicle exhaust durability procedure
    B. Standard bench aging exhaust durability procedure
    1. The Standard Bench Cycle (SBC)
    2. The Bench Aging Time (BAT) calculation
    3. The effective reference temperature for the SBC
    C. Customization of the standard procedures
    1. Customization of the Standard Road Cycle
    2. Customization of the standard bench procedures
    3. Replication by outside parties
    D. Using In-Use Verification Program (IUVP) data to improve 
durability predictions
    E. Evaporative and refueling durability
    F. Effective date and carryover of existing durability data
    G. Miscellaneous regulatory amendments and corrections
IV. What are the economic and environmental impacts?
    A. Economic impacts
    1. Comparison to CAP 2000 economic impacts
    2. Economic impact of today's final rule
    B. Environmental impacts
V. What are the Statutory and Executive Order Reviews for this Rule?
    A. Executive Order 128866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132 (Federalism)
    F. Executive Order 13175: Consultation and Coordination with 
Indian Tribal Governments
    G. Executive Order 13045: Children's Health Protection
    H. Executive Order 13211: Actions that Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer Advancement Act
    J. Congressional Review Act

I. Background

A. Overview of certification process, CAP 2000 history

    Before a manufacturer may introduce a new motor vehicle into 
commerce, the manufacturer must obtain an EPA certificate of conformity 
indicating compliance with all applicable emission standards over the 
vehicle's useful life period. The useful life for cars and light trucks 
is currently 100,000 miles or 10 years, whichever occurs first; for 
heavy light trucks, medium duty passenger vehicles (MDPV) and complete 
heavy duty vehicles the useful life period is 120,000 miles or 11 
years, whichever occurs first. [Section 202(d) of the Clean Air Act and 
40 CFR 86.1805-04]
    To receive a certificate, the manufacturer submits an application 
to EPA containing various information specified in the regulations, 
including emissions test data. EPA reviews the submitted information as 
well as any other relevant information, and issues a Certificate upon a 
determination that the manufacturer has demonstrated that its new motor 
vehicle will meet the requirements of the Clean Air Act (Act) and the 
regulations. [40 CFR 86.1848-01] A certificate of conformity is 
effective for only one model year;

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therefore, new vehicle certification must occur annually.
    EPA's regulations detail the process motor vehicle manufacturers 
must follow to obtain EPA emissions certification. In 2000, EPA issued 
a comprehensive update to the certification regulations for light-duty 
vehicles and light-duty trucks.\1\ These certification regulations are 
known as ``CAP [Compliance Assurance Program] 2000''.\2\ They include 
detailed procedures on the selection of vehicles for testing and 
testing procedure, specifications on the information that must be 
submitted to EPA, and other requirements pertaining to reporting and 
testing.
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    \1\ Separate certification regulations exist for heavy-duty 
highway vehicles and engines, which refer to the light-duty 
certification procedures. Today's final rule will apply to those 
subsets for heavy-duty vehicles which use the same certification 
procedures as light-duty trucks. for convenience, the term 
``vehicle'' or ``motor vehicle'' will be used in this preamble to 
mean those light-duty and heavy-duty motor vehicles subject to these 
regulations.
    \2\ 63 FR 39654 (July 23, 1998).
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    Issuance of a certificate is based on a determination by EPA that 
the vehicles at issue will conform with the applicable emissions 
standards. Compliance with the emissions standards requires that the 
vehicles meet the standards for the specified useful life period. A 
determination of compliance, therefore, must be based on an evaluation 
of both the performance of the vehicles' emissions control system when 
new, as well as performance over the entire time period of the 
vehicles' useful life.\3\
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    \3\ Since a certificate must be issued before the new vehicles 
may be introduced into commerce, the emissions testing and other 
relevant data and information used to support an application for a 
certificate are usually developed on pre-production prototypes.
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    The process of predicting how and to what degree a vehicle's 
emission levels will change over its useful life period [emissions 
deterioration] as well as the robustness of the vehicle's emission-
related components [component durability] is known as an emission 
durability demonstration.\4\ Today's final rule specifies the methods 
that manufacturers must use to determine emissions deterioration for 
the purpose of certification.
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    \4\ The durability demonstration program consists of two 
elements: emission deterioration and component durability. Emission 
deterioration prediction is a process of predicting to what degree 
emissions will increase during the vehicles useful life. The 
deterioration factor (DF) is a measure of deterioration. Component 
durability is a demonstration that the emission control components 
will not break and will continue to operate as described in the 
Application for Certification during the minimum maintenance 
interval proscribed in 40 CFR 1834-01. The component durability 
demonstration is conducted by the manufacturer using good 
engineering judgement.
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    Over the years, EPA has promulgated regulations prescribing several 
different emissions durability demonstration methods to fulfill EPA's 
need to determine compliance with emission standards over the vehicle's 
full useful life. The following is a short summary of this prior 
regulatory history, to put today's final rule in context.

B. Durability Demonstration Process History

1. Durability Demonstration Methods Used Prior to the CAP 2000 
Regulations
    Prior to CAP 2000, EPA's regulations (ref. 40 CFR Part 86) 
specified the method to demonstrate a vehicle's emission durability. 
The method used a whole vehicle mileage accumulation cycle, commonly 
referred to as the Approved Mileage Accumulation (AMA) cycle. It 
required manufacturers to accumulate mileage on a pre-production 
vehicle, known as a durability data vehicle (DDV), by driving it over 
the prescribed AMA driving cycle for the full useful life mileage.\5\ 
This was to simulate the real-world aging of the vehicle's emissions 
control systems over the useful life.
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    \5\ At the time this durability procedure was effective, the 
useful life mileage for light-duty vehicles was 100,000 miles. Refer 
to 40 CFR 86.1805-04 for current useful life mileage values.
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    The DDV was tested in a laboratory for emissions at periodic 
intervals during AMA mileage accumulation, and a linear regression of 
the test data was performed to calculate a multiplicative deterioration 
factor (DF) for each exhaust constituent. Then, low mileage vehicles 
more representative of those intended to go into production (referred 
to as ``emission data vehicles,'' or EDVs) were emission-tested. The 
emission results from these tests were multiplied by the DFs \6\ to 
project the emissions levels at full useful life (referred to as the 
``certification levels''). The certification levels had to be at or 
below the applicable emission standards in order to obtain a 
certificate of conformity.
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    \6\ A multiplicative DF is calculated by performing a least-
squares regression of the emission versus mileage data for each 
exhaust emission constituent and dividing the emission level at full 
useful life (historically, 100,000 miles) by the emission level at 
the 4,000 mile point.
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    EPA was concerned about the ability of any fixed cycle--including 
the AMA cycle--to produce emission durability data that accurately 
predicted in-use deterioration for all vehicles. EPA had particular 
concerns that the AMA did not represent current driving patterns and 
did not appropriately age current design vehicles. In addition, 
manufacturers have long identified the durability process based on 
mileage accumulation using the AMA cycle as very costly and requiring 
extensive lead time for completion. As a result, EPA came to believe 
that the AMA had become outdated \7\.
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    \7\ Reference: 63 FR 39653, 39659 (July 23, 1998) (CAP 2000 
NPRM).
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    The AMA cycle was developed before vehicles were equipped with 
catalytic converters. It contains a substantial portion of low speed 
driving, designed to address concerns about engine deposits. While 
engine deposits were a major source of emissions deterioration in pre-
catalyst vehicles, the advent of catalytic converters, better fuel 
control, and the use of unleaded fuel shifted the causes of 
deterioration from low speed driving to driving modes which include 
higher speed/load regimes that cause elevated catalyst temperatures. 
The AMA driving cycle does not adequately focus on these higher 
catalyst temperature driving modes. It also contains numerous driving 
modes which do not significantly contribute to deterioration. This 
makes the process longer but adds little benefit in predicting emission 
deterioration.
    In response to these concerns, EPA began a voluntary emission 
durability program in the 1994 model year for light-duty vehicles. This 
program allowed manufacturers to develop their own procedures to 
evaluate durability and deterioration subject to prior Agency 
approval.\8\ EPA's approval criteria required the manufacturer to 
demonstrate that the durability procedures would cover a significant 
majority of in-use vehicle's emission deterioration.\9\ One additional 
condition for approval was that the manufacturer conduct or fund an in-
use test program to evaluate the effectiveness of its predictions. The 
initial program was referred to as revised durability program

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I (RDP I). It was an interim program scheduled to expire after the 1995 
model year and was intended to serve as a bridge to an anticipated 
complete revision to the durability process. The provisions of RDP I 
were extended in a series of regulatory actions.\10\ Ultimately, the 
Agency instituted a comprehensive revision to the durability process as 
part of the CAP 2000 rulemaking.
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    \8\ EPA approved three types of emission durability programs 
under these procedures: whole vehicle, full mileage, whole vehicle, 
accelerated mileage; and bench aging procedures which involved 
thermal aging of the catalyst-plus-oxygen-sensor system.
    \9\ Reference EPA Guidance Letter No. CD-94-13, ``Alternative 
Durability Guidance for MY94 through MY98'', dated July 29, 1994. 
This letter explained that as-received, un-screened in-use data 
should be compared to vehicles run on the alternative durability 
program (ASADP). A ``significant majority'' of the in-use data 
should be covered by the durability program. We defined the 
acceptance ceriteria in that letter as follows: ``EPA does not 
require ASADPs to meet a specific minimum severity level (or 
confidence level) because different methods may be used to estimate 
the degree of severity. * * * However, an ASADP would be acceptable 
to EPA if EPA believes that it were designed to match the in-use 
deterioration of 90-95 percent of vehicles in the engine family.''
    \10\ Ref. 59 FR 36368 (July 19, 1994), 62 FR 11082 (March 11, 
1997) 62 FR 11138 (March 11, 1997) and 62 FR 44872 (August 22, 
1997).
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    For evaporative and refueling emissions deterioration, EPA allowed 
manufacturers to develop their own process to either bench age 
components or do whole vehicle aging, also subject to Agency review and 
approval. The evaporative and refueling deterioration factor is 
required to be additive.\11\
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    \11\ An additive DF is calculated by performing a least-squares 
regression of the emission versus mileage data for each exhaust 
emission constituent and subtracting the 4,000-mile emission level 
from the full useful life emission level (historically, 100,000 
miles). The DF is then used with emission data from the emission 
data vehicle to demonstrate compliance with the standards for the 
purpose of certification. The sum of the emissions from the EDV plus 
the additive DF is referred to as the certification level and must 
be less than or equal to the emission standard to receive a 
certificate of conformity.
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2. Emission Durability Procedures Under CAP 2000
    The CAP 2000 rulemaking was a comprehensive update to the entire 
light-duty vehicle certification process. One part of this involved the 
manufacturer's required demonstration of emission durability. The 
Agency eliminated the requirement for the use of AMA for new durability 
demonstrations. In CAP 2000, the Agency replaced the AMA-based 
durability program with a durability process similar to the optional 
RDP-I program. Each manufacturer, except small volume manufacturers, 
was required to develop an emission durability process which would 
accurately predict the in-use deterioration of the vehicles they 
produce. The manufacturer had the flexibility to design an efficient 
program that met that objective.
    The manufacturer's plan was then reviewed by EPA for approval.\12\ 
Approval from the Agency required a demonstration that the durability 
process was designed to generate DFs representative of in-use 
deterioration. This demonstration was more than simply matching the 
average in-use deterioration with DFs. Manufacturers needed to 
demonstrate to EPA's satisfaction that their durability process would 
result in the same or more deterioration than is reflected by the in-
use data for a significant majority of their vehicles. Manufacturers 
were required to provide evidence that their durability process 
resulted in predicted emission deterioration that were equal to or more 
severe than the deterioration rates experienced by a significant 
majority (approximately 90%) of candidate in-use vehicles.\13\ 
Furthermore, this demonstration was required to cover the breadth of 
the vehicles covered by the durability procedure.
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    \12\ The CAP 2000 regulations ``grand-fathered'' procedures 
which had been already approved under the RDP provisions. 
Consequently, these grand fathered procedures were not approved 
again under the CAP 2000 provisions. [63 FR.39661]
    \13\ Candidate in-use vehicles are vehicles selected under the 
provisions of the in-use verification program (IUVP). This includes 
mileage restrictions, procurement requirements, and screening 
requirements designed to eliminate only tampered, mis-used or unsafe 
vehicles. [reference: 40 CFR 86.1845-01 and 40 CFR 86.1845.04]
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    This evaluation concerning coverage of a significant majority of 
the in-use data was usually made independently on several potential 
worst-case vehicles which bound the envelope of vehicles covered by the 
durability procedure. Manufacturers typically demonstrated that 
emission deterioration predicted by their durability program would 
cover approximately 90 percent of the in-use population using one (or 
more) of the following sources of data: in-use emission tests, in-use 
driving characteristics, or in-use catalyst temperature measurements. 
At that time EPA had not developed a specific required method to make 
this demonstration.
    Two major types of durability processes emerged from the CAP 2000 
experience: whole vehicle and bench aging processes.
    The whole vehicle aging procedures involve driving vehicles on a 
track or dynamometer on an aggressive driving cycle of the 
manufacturer's design. In general, the speed, acceleration rates, and/
or vehicle load are significantly increased compared to the AMA cycle 
or normal in-use driving patterns. The vehicle can be driven either for 
full useful-life mileage, or, for a higher stress cycle, the vehicle 
can be driven for a reduced number of miles (e.g., 1 mile on the high 
speed cycle equals 2 miles in use). In either case, the vehicle is 
tested periodically and a DF is calculated.
    The bench aging procedures involve the removal of critical emission 
components, such as the catalyst and oxygen sensor, and the accelerated 
aging of those components on an engine dynamometer bench.\14\ During 
the bench aging process important engine/catalyst parameters are 
controlled to assure proper aging. Usually, elevated catalyst 
temperatures are maintained while fuel is controlled to include lean, 
rich, and stoichiometric control. Through a series of tests, 
manufacturers determine the amount of time needed to bench-age a 
catalyst so it is aged to the equivalent of 100,000 miles. In some 
cases the manufacturer developed the amount of aging time using 
catalyst temperature data measured on a road cycle. In other cases, the 
manufacturer developed the aging time through a trial and error 
process. Typical bench aging periods are 100-300 hours, although these 
can vary from manufacturer to manufacturer. Sources of deterioration 
other than thermal aging can be accounted for by aging the catalyst for 
an additional amount of time.
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    \14\ An engine dynamometer bench generally consists of an engine 
dynanometer, a ``slave'' engine, and required controllers and 
sensors to achieve the desired operation of the engine on the 
dynanometer.
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    The CAP 2000 regulations allow manufacturers to choose from three 
different methods to demonstrate emissions durability. Manufacturers 
could calculate additive DFs, multiplicative DFs, or test EDVs with 
aged hardware \15\ installed on them.
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    \15\ Under this alternative, emission components aged to the 
equivalent of full useful life would be installed on EDVs. The test 
data from the EDV would then serve to establish the certification 
level and show compliance with the full useful life emission 
standards.
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    Regardless of whether manufacturers used whole vehicle or bench 
aging durability procedures, CAP 2000 also required the manufacturer to 
later collect emission data on candidate in-use vehicles selected under 
the provisions of the in-use verification program (IUVP).\16\ Among 
other uses of the data, the IUVP data must be used by the manufacturer 
to check on and improve its durability program. The data also is 
available to assist the Agency to target vehicle testing for its recall 
program. The Agency may intercede \17\ when the in-use data

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indicate the durability process underestimates in-use emission levels.
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    \16\ Reference: 40 CFR 86.1845-01 and 40 CFR 86.1845-04.
    \17\ The Agency may withdraw approval for a durability process 
if the Administrator determines, based on IUVP or other data, that 
the durability process does not accurately predict emission levels 
or compliance with the standards. [Ref. 40 CFR 86.1923-01(h)]. In 
addition, where the average in-use verification data for a test 
group (or several test groups) exceeds 1.3 times the applicable 
emission standard and at least 50% of the test vehicles fail the 
standard in use, manufacturers are required to supply additional 
``recall quality'' in-use data. [Ref. 40 CFR 86.1846-01].
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    The CAP 2000 regulations did not change the previous procedures 
used to obtain DFs for evaporative/refueling families.

C. Ethyl Petition To Reconsider the CAP 2000 Rules

    On August 17, 1999, Ethyl Corporation petitioned EPA to reconsider 
the CAP 2000 regulations. EPA requested public comment on the petition, 
64 FR 60401 (November 5, 1999 and 64 FR 70665 (December 17, 1999), and 
received comments from various interested parties. After consideration 
of the petition and of all comments, EPA denied the petition for 
reconsideration. 66 FR 45777 (August 30, 2001).
    Ethyl Corporation also petitioned the Agency to reconsider the 
final rule entitled ``Emissions Control, Air Pollution From 2004 and 
Later Model Year Heavy-Duty Highway Engines and Vehicles; Light-Duty 
On-Board Diagnostics Requirements, Revision; Final Rule,'' 65 FR 59896-
59978 (referred to here as the ``Heavy Duty Rule''). After 
consideration of the petition and all of the comments, EPA denied the 
petition for reconsideration. 66 FR 45777 (August 30, 2001).

D. Judicial Review of the CAP 2000 Rules

    Ethyl Corporation petitioned for review of the CAP 2000 rulemaking, 
claiming among other things that the CAP 2000 durability provisions 
were unlawful as EPA had not promulgated methods and procedures for 
making tests by regulation as required by Sec.  206. [Ethyl Corp. v. 
EPA, 306 F.3d 1144 (DC Cir. Oct. 22, 2002).]
    In an opinion issued on October 22, 2002, the Court found that the 
CAP 2000 regulations did not satisfy the requirements of section 206(d) 
of the CAA to establish methods and procedures for making tests through 
regulation.
    The Court recognized that there was an important distinction 
between an EPA regulation that established general or vaguely 
articulated test procedures, with more specific details provided in a 
later proceeding, and a regulation which failed to establish any test 
procedures at all and only adopted procedures for the later development 
of tests. The former situation would receive deferential judicial 
review under the applicable case law. The latter case, however, would 
fail to meet the requirements of section 206(d). The Court held that 
the CAP 2000 regulations fell into this latter group, and were improper 
because EPA itself failed to establish any test procedures at all in 
the regulation, vaguely articulated or not. EPA's regulation provided 
only for the manufacturer to develop its own test procedure and submit 
it for later EPA approval. This was inconsistent with the scope of 
section 206(d), [Ethyl at 1149-50.]
    The Court also said that ``nothing in our opinion requires that EPA 
use only a `one-size-fits-all' test method. All that is required is 
that it establish its procedures, no matter how variegated, `by 
regulation.' '' [Ethyl at 1150.]
    Since the issue before the Court was the legality of EPA's adoption 
of the CAP 2000 durability provisions, EPA believes the court's 
vacature of ``the CAP 2000 program'' is limited to vacating the CAP 
2000 durability provisions.
    The Court also remanded the case to EPA with instructions to 
establish test methods and procedures by regulation. Today's final rule 
is the result of the court's decision, and is limited to emission 
durability procedures.

E. Applicability of the NPRM Preamble Discussion

    Unless otherwise indicated below, the discussion presented in the 
preamble to the notice of proposed rulemaking published at 69 FR 17532 
is applicable to this final rule.

F. Supplemental Notice Regarding Component Durability

    The Agency received a comment from Afton Chemical Corporation 
(``Afton,'' formerly known as Ethyl suggesting that EPA did not address 
the component durability portion of the emission durability process and 
should establish a procedure for determining component durability. 
After the Court decision which remanded EPA to write new regulations 
regarding emissions durability, EPA discussed with the Petitioner and 
automotive manufacturers the ramifications of that decision. To aid in 
these discussions, EPA provided a draft ``mark-up'' version of the CAP 
2000 regulations, showing via stricken text exactly which regulations 
we believed had been vacated.\18\ We did not strike out the regulatory 
language regarding component durability. At that time, neither the 
petitioner nor the automotive manufacturers spoke out in opposition to 
this. We did not propose new procedures for component durability and 
proceeded with the proposed durability regulation, which retained the 
``good engineering judgment'' language for component durability.\19\ 
Today's final rule includes only procedures for the emission 
deterioration portion of the durability process, because our 
understanding was that component durability was not at issue. However, 
Afton's comments are significant enough, that we believe it is 
appropriate to take the opportunity for further comment on component 
durability regulations. We believe it is appropriate, given the need 
for notice and comment for all interested parties, that we treat 
component durability in a separate action. Therefore, in addition to 
today's final rule, EPA is also today publishing a separate 
Supplemental Notice of Proposed Rulemaking requesting comments on a 
proposal which addresses component durability. Today's final rule has 
not revised the regulatory language for component durability.
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    \18\ A copy of the strike-out version of CAP 2000 language is 
included in the Docket to this regulation.
    \19\ Ref. 69 FR 17533 ``EPA is not proposing to change the 
existing regulations for determining emission-related component 
durability''.
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II. Summary and Analysis of Comments

    EPA received comments from the automotive makers Ford, Volkswagen 
and Cummins, two automotive trade associations on behalf of their 
member automotive companies, the Afton Chemical Corporation (formerly 
know as the Ethyl Corporation), and one comment from a private citizen.
    The comments have been grouped together by subject matter. The 
following discussion presents the summary of EPA's proposal, of the 
comments received on that proposal, and EPA's response to those 
comments.

A. The Durability Objective

    Summary of proposed rule. The proposed rules included a provision 
that defined the durability objective [Ref 40 CFR 86.1823-08(a)] as 
follows: ``The durability program must predict an expected in-use 
emission deterioration rate and emission level that effectively 
represents a significant majority (approximately 90 percent) of the 
distribution of emission levels and deterioration in actual use over 
the full and intermediate useful life of candidate in-use vehicles \20\ 
of each vehicle design which uses the durability program.''
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    \20\ Candidate in-use vehicles are vehicles selected under 
provisions of the in-use verification program (IUVP). This includes 
mileage restrictions, procurement requirements, and screening 
requirements designed to eliminate only tampered, mis-used or unsafe 
vehicles. [Reference: 40 CFR 86.1845-01 and 40 CFR 86.1845-04]
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    Summary of Comments. The Alliance and AIAM commented that the 
phrase ``approximately 90 percent'' could

[[Page 2814]]

effectively increase the stringency of the standards by ignoring 
whether vehicles are passing the standards in-use and focusing on the 
probability distribution that in-use emissions exceed the emission 
levels projected at certification. This represents a substantial and 
unnecessary departure from the CAP 2000 rules. Instead, the rules 
should be in line with the ``significant majority'' goal espoused in 
CAP 2000 and the RDP guidance letter (CD-94-13, July 29, 1994).
    In response to a request by EPA to clarify their comments, the 
Alliance stated that they were concerned that the proposed provision in 
the regulations themselves which defined ``significant majority'' to 
mean ``approximately 90 percent'' could be interpreted to establish an 
inflexible percentage criterion and eliminate EPA's discretion to 
consider other factors when evaluating the effectiveness of a 
manufacturer's durability program taken as a whole.
    Response to Comments. The purpose of the durability program is to 
provide EPA with reasonable assurance that vehicles covered by a 
certificate of conformity will, in actual use, comply with the 
applicable emission standards over their full useful life. As discussed 
in the proposal, production variability or other reasons can lead to 
differences in actual emission levels among vehicles of the same 
nominal design.
    In the CAP 2000 rulemaking, EPA required that a durability program 
adequately predict emission deterioration for a significant majority of 
candidate in-use vehicles. In the CAP 2000 program, EPA had typically 
considered ``significant majority'' to mean approximately 90 percent 
coverage of the distribution of in-use deterioration. This concept was 
discussed in the preamble to the CAP 2000 rule \21\; however, EPA had 
not set a strict numerical criteria in the CAP 2000 regulations.
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    \21\ Ref. CAP 2000 NPRM preamble 63 FR 39661.
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    It was not the EPA's intention to establish in this rule a single 
rigid method or an inflexible numerical criteria to evaluate the 
durability objective. EPA understands the Alliance's concerns that the 
proposed language might lend itself to a more rigid interpretation that 
may limit EPA discretion and/or impose unintended burdens on 
manufacturers. Consequently, EPA has removed the parenthetical phrase 
``approximately 90 percent'' from the finalized durability objective 
language in the regulations.
    By making this change we are not relaxing the requirement. The 
manufacturer must still demonstrate that a customized/alternative 
durability procedure is expected to effectively represent a significant 
majority of the distribution of emission deterioration in actual use to 
obtain EPA approval to use the procedure for certification. EPA and the 
manufacturers will still review IUVP data and/or other data to 
determine if the durability objective was achieved in use and whether 
it is appropriate to continue to use that durability process for future 
certification requests. EPA will consider a variety of different 
evidence and/or analyses that the durability objective has been or is 
expected to be achieved. However, a demonstration that approximately 90 
percent of the distribution of in-use emission deterioration or 
emission levels is effectively represented by the durability procedure 
will continue to be a satisfactory showing for this purpose.
    The following section discusses how the durability objective will 
be used to evaluate certification durability procedures based on in-use 
emission data.

B. Evaluation of the Certification Durability Procedures Based on In-
Use Emissions Data

    Summary of Proposal. Manufacturers must use information gathered 
from the IUVP, as well as other sources of in-use emissions data, to 
periodically review whether the durability procedure it employs 
achieves the durability objective. EPA may require a manufacturer to 
perform an analysis to evaluate its durability procedure. EPA may 
withdraw approval of a durability procedure, or require modifications 
to the procedure, if the Agency determines that the durability 
objective is not being achieved by the durability procedure. [Ref. 
86.1823-08 (i) and (j)]
    Summary of Comments. The Alliance and AIAM stated that they had 
concerns that a number of variables could affect IUVP emission data 
(including in-use fuel characteristics, mal-maintenance, testing 
variability, small sample size, random recruitment and as-received 
testing (rather than testing properly maintained and used vehicles)) 
and that these variables could affect the accuracy of decisions made 
using IUVP data. They stated that these concerns ``were already 
addressed in the CAP 2000 rulemaking in an appropriate fashion''.
    To illustrate their concern, the Alliance and AIAM provided this 
example: All in-use vehicles can be well below the applicable 
standards, but the durability procedure could be deemed deficient under 
the proposed rule merely because in-use emissions exceed the emission 
levels projected at certification.
    The Alliance and AIAM also suggested that ``If the IUVP data show 
that a manufacturer meets emissions standards in use (because, for 
example, the manufacturer certified with a sufficient compliance 
margin, known as ``headroom''), then the Agency should not be concerned 
and should not make decisions based on the accuracy of the 
certification emission deterioration seen in isolation.''
    In response to a request by EPA to clarify their comments, the 
Alliance stated that the new provision could be interpreted to require 
changes in their durability programs even when a significant majority 
of candidate in-use vehicles comply with emission standards. They 
believed that the proposed rule could, therefore, effectively tighten 
the applicable emission standards.
    Ford commented that: (1) The proposal effectively increases the 
stringency of the standards. (2) The focus of this criteria appear to 
change from the strawman which compared the IUVP emission results to 
the standard and the highest certification level of all certification 
and running change tests. (3) Applying the 90 percent criteria 
[significant majority] criteria to IUVP data (``as received vehicles'') 
rather than ``properly maintained and used'' vehicles [the quality of 
data used to order recalls] further increase the stringency. (4) The 
proposed requirement forces change and cost increases to methods where 
100% of the IUVP data meet applicable standards. (5) Reviewing the rate 
of deterioration is inconsistent with the use of certifying with aged 
components (rather than calculating a deterioration factor).
    The Alliance and AIAM also commented Review of durability processes 
should only be required when the in-use confirmatory test criteria are 
triggered.
    Response to Comments. EPA did not propose, nor are we finalizing, 
any changes to the IUVP testing program promulgated in the CAP 2000 
rulemaking. As discussed in the proposal, EPA does not believe these 
provisions were vacated by the Court's decision and they remain 
effective without any further action required by the Agency.
    The provisions for using IUVP emissions data and/or other 
information to evaluate a durability procedure and for the 
Administrator to reject the use of a durability procedure based on such 
an evaluation were also contained in the CAP 2000 rules. The CAP 2000 
rule established the requirement to reject a

[[Page 2815]]

durability procedure when ``the durability process has not been shown 
to effectively predict emission levels or compliance with the standards 
in use on candidate vehicles'' using this data. This requirement is 
practically equivalent to the ``not achieving the durability 
objective'' language in the proposal. As long as in-use vehicle data is 
below the standards, the durability procedure would be considered 
acceptable, even if the in-use emissions exceed the emission levels 
projected at certification. However, if it was found that the in-use 
emissions were significantly higher than the projected certification 
levels, we may decide to review the durability procedure to determine 
why the in-use emission results are so far off from the projected 
certification results in order to improve the procedure being used.
    We disagree with the comment that the comparison of IUVP emission 
data to the durability objective in the proposal is a new requirement 
(not contained in the CAP 2000 rules) that increases the stringency of 
the standards. As discussed in the last paragraph, the basis for the 
evaluation of a durability program in CAP 2000 was ``candidate in-use 
vehicle'' which are defined to be vehicles eligible for selection by 
the IUVP program. Clearly, comparing actual IUVP emission data to the 
durability objective is precisely what was intended by this 
requirement. Consequently, this requirement is not new and therefore 
does not increase stringency of the standards. Ford is confusing the 
``well maintained and used'' quality of data requirement that applies 
to ordered recalls with the process of evaluating the effectiveness of 
a durability process for certification. As discussed in the CAP 2000 
rule, EPA does not intend to order recalls of vehicles using unscreened 
IUVP data. EPA did not propose, nor are we finalizing, any provision 
that would change the process of ordering recalls of non-complying 
vehicles by using unscreened IUVP data.
    We continue to believe it is necessary to re-evaluate a 
manufacturer's durability process using actual in-use emission, data 
such as IUVP data, when that information becomes available. It is only 
through such review that we can be assured that the predictions made at 
the time of certification are actually valid in use. When that data 
indicate that the durability process does not achieve the durability 
objective in actual use, then the Agency may decide to withdraw 
approval for the durability procedure or require modification to the 
procedure for future certification purposes. Again, such remedial 
action is necessary for the Agency to assure an effective certification 
program. It would be reckless for the Agency to allow the continued use 
of a unmodified durability process for future certification once it has 
been shown to be ineffective in actual use for similar vehicles.
    We disagree with the suggestion that review of the durability 
procedures should only occur when the in use confirmatory program 
(IUCP) triggers \22\ are activated. The confirmatory test criteria are 
considered to be a screening criteria that identifies the very worst 
cases only for automatic reconsideration. EPA expects that there will 
be cases where the durability procedures are not working satisfactorily 
for a particular test group that are not identified by these criteria. 
Furthermore, reviewing in-use data in large groups allows the Agency to 
determine if there is an underlying trend that a durability process is 
not satisfactorily achieving the durability objective. In those cases, 
EPA is naturally and justifiably concerned about the accuracy of the 
durability process. These reviews conducted on a case-by-case basis are 
necessary for the Agency to assure an effective certification program.
---------------------------------------------------------------------------

    \22\ Mean In-Use Verification Program (IUVP) emissions for a 
test group exceed threshold of 1.3 times the certification emission 
standard and at least 50% of test vehicles for that test group fail 
for the same pollutant.
---------------------------------------------------------------------------

    EPA has retained the proposed provision to eliminate 
unrepresentative in-use data when making this determination.
    EPA has not established a single required method to perform an 
analysis to evaluate the effectiveness of the durability process using 
in-use emission data. The Agency will consider all information and 
analyses presented by the manufacturer submitted within the 60-day 
period specified in the regulations before reaching a final decision to 
withdraw approval for a durability procedure. Although there is no 
specified procedure for this evaluation, there are several observations 
which are applicable to this process.
    Calculating deterioration rates only from in-use emission results 
conducted at various vehicle mileage points on randomly procured 
vehicles within a test group can be misleading. It is well known that 
individual vehicle configurations within a test group or durability 
group will have different levels of absolute emissions. Since the IUVP 
uses random procurement, it is possible that the lower emission 
vehicles would be tested at low mileage and the higher emission 
vehicles would be tested at high mileage. This situation would lead to 
a exaggeratedly high calculated deterioration rate. This, in turn, 
could lead to the false determination that the durability process does 
not meet the durability objective. Comparing individual in-use emission 
levels to the certification levels or the applicable emission standards 
will result in more accurate evaluations of the in-use data and is 
recommended for that reason.
    It is better to make overall decisions about the effectiveness of a 
durability procedure using the largest possible data set of comparable 
vehicles. Consequently, EPA recommends performing analyses on a broad 
group of comparable vehicles rather than on single test groups or other 
small data sets. Comparable vehicles complying with different standards 
may be combined into the same analysis if the emission levels are 
standardized by the ratio of the emission standards.
    We agree with the Alliance and AIAM that the Agency should not make 
decisions based on the accuracy of the certification emission 
deterioration seen in isolation. Compliance margin should also be 
considered in the analysis.
    The proposed and finalized rules discuss ``effectively representing 
a significant majority'' (emphasis added). The word ``effectively'' in 
this context is intended to allow the use of compliance margin (also 
called ``headroom'') to expand the predictive coverage of a durability 
program. As stated previously, the purpose of the durability program is 
to provide EPA with reasonable assurance that vehicles covered by a 
certificate of conformity will, in actual use, comply with the 
applicable emission standards over their full useful life.
    This purpose may be accomplished by employing a durability process 
that directly predicts emission levels that represent a significant 
majority of the distribution of emission levels in actual use. 
Alternatively, the durability process may under-predict emission 
levels, but when coupled with the compliance margin, a significant 
majority of the vehicles comply with the emission standards in actual 
use. Providing that the same amount of compliance margin is used in 
future certification requests, it is reasonable to conclude that such a 
durability process when coupled with this level of compliance margin 
effectively represents a significant majority of the distribution of 
emission levels in actual use.
    For example: if after removing unrepresentative data only 70 
percent of

[[Page 2816]]

the emission data was less than or equal to the predicted value (the 
certification level determined at certification time), then one could 
conclude that the predictive accuracy of the durability process was 
approximately 70% which would not constitute a ``significant 
majority''. If, however, when compliance margin is taken into account, 
95% of the vehicles comply with the applicable emission standards, it 
could be safely concluded that a significant majority of vehicles are 
effectively represented by the durability procedure. Such an analysis 
would be performed separately for each applicable emission constituent 
and associated emission standard.
    Based on the preceding description of how the ``effectively 
represent'' criteria may be implemented, we disagree with the Alliance, 
AIAM, and Ford that the proposed requirements will result in the Agency 
withdrawing approving for a durability process when all the IUVP data 
is complying with the applicable standards.
    Lastly, we do not see an inconsistency, as a comment suggests, in 
comparing IUVP emission data to the durability objective when the 
manufacturer elects to certify using aged components rather than 
calculate a deterioration factor. EPA is allowing flexibility in the 
method for the manufacturer to conduct this analysis. EPA does not 
require (nor do we recommend, as discussed above) comparing 
certification DFs to DFs calculated from IUVP data. EPA's preferred 
method for the analysis involves comparing IUVP emission results to 
certification levels and standards; all of this data is available to 
manufacturers electing to certify with aged components rather than 
calculating a certification DF.
    In summary, the Agency is retaining the proposed requirement to 
require manufacturers to evaluate the durability procedures using in-
use emission data generated on candidate vehicles (such as IUVP data) 
and the authority for EPA to withdraw approval of the durability 
procedure if the durability objective was not achieved in actual use on 
comparable vehicles. The Agency did not propose, nor are we finalizing, 
a specific required method to evaluate certification durability 
procedures based on in-use emissions data. However, a demonstration 
that approximately 90 percent of the distribution of in-use emission 
results (considering each emission constituent separately) comply with 
the applicable standard will be a satisfactory showing that the 
durability objective has been achieved.

C. Standard Whole Vehicle Durability Procedure

1. Standard Road Cycle (SRC)
    Summary of Proposal. The standard whole vehicle durability 
procedure consists of mileage accumulation on a durability vehicle 
following the standard road cycle (SRC). The SRC was defined in the 
proposal in Appendix V of part 86.
    Summary of Comments. The Alliance and AIAM commented that the 
proposed standard road cycle is effective at meeting the Agency's 
intent.
    Response to Comments. Having received no adverse comments on the 
proposal, EPA is finalizing the SRC as proposed.
2. Vehicle Ballasting on SRC Mileage Accumulation
    Summary of Proposal. The proposed rules required that during 
mileage accumulation ``the durability data vehicle (DDV) must be 
ballasted to a minimum of the loaded vehicle weight for light-duty 
vehicles and a minimum of the ALVW for all other vehicles'' [Ref 
86.1823-08(c)(1)(iii)].
    Summary of Comments. The Alliance and AIAM suggested that EPA 
should harmonize the vehicle weight requirements for truck DDVs with 
the current emission testing requirements for emission data vehicles 
(EDV).
    Response to Comments. The proposal required heavier payload for 
truck mileage accumulation because trucks are designed to carry loads 
in addition to transporting the occupants of the vehicle. In our review 
of manufacturer vehicle design and durability processes, we found that 
trucks have special design and durability requirements acknowledging 
their load carrying capability. We also believe that trucks carry loads 
in actual use some fraction of the time.
    The standard whole vehicle durability program is designed to 
achieve the durability objective. The durability objective requires the 
durability program to represent a significant majority of the 
distribution of emission levels and deterioration experienced in actual 
use on those vehicles. To reach this goal of significant majority 
coverage, EPA believes that it is necessary to address heavier vehicle 
loads that occur in trucks some fraction of the time. The adjusted 
loaded vehicle weight (ALVW) loading requirement requires ballasting 
with half the payload rather than 300 pounds (the loaded vehicle weight 
which is applicable to light duty vehicle mileage accumulation in the 
proposal).
    The amount of ballasting for mileage accumulation should not be 
confused with the vehicle weight basis for conducting emission testing. 
EPA did not propose, nor are we finalizing, any change to the weight 
basis for emission testing, including testing that may be performed on 
the DDV to calculate a deterioration factor (DF).
    Although EPA continues to believe it is necessary to ballast most 
trucks to ALVW to assure that the durability objective is achieved, 
this requirement may to too severe for some light light-duty 
trucks.\23\ These lighter trucks are much more frequently used only for 
passenger transportation and more rarely used to transport significant 
payloads. Consequently, EPA is changing this provision in the final 
rule to require ballasting during mileage accumulation to a minimum of 
the loaded vehicle weight to apply to both light-duty vehicles and 
light light-duty trucks. We are retaining the provision to ballast all 
other vehicles to a minimum of the ALVW.
---------------------------------------------------------------------------

    \23\ Light light-duty trucks are trucks that are rated through 
6000 pounds GVWR. This includes truck classes LDT1 and LDT2.
---------------------------------------------------------------------------

3. Calculating the DF From Mileage Accumulation of 75% of Full Useful 
Life Mileage
    Summary of Proposal. The description of the proposed standard 
whole-vehicle durability procedure contained a provision [Ref. 86.1823-
08(c)(2)] that would require mileage accumulation of at least 75% of 
the full useful life mileage. If the mileage accumulation was less than 
100% of the useful life mileage this provision would require the DF to 
be based on the upper 80 percent statistical confidence limit 
calculated from the emission data.
    Summary of Comments. The Alliance and AIAM commented that 
projecting a full-useful life DF from data generated over 75% percent 
of the useful life is sufficient without adding the proposed 80% 
confidence factor. The proposed requirement is more stringent than the 
original CAP 2000 and Tier 1 requirement for projecting DFs. Projected 
full useful life emissions should use mean values rather than 80% 
statistical point.
    Response to Comments. We disagree. EPA promulgated the provision to 
allow reduced (75% rather than 100% useful life) mileage accumulation 
in the CAP 2000 and Tier 1 rules to address the concern of the 
excessive time necessary to complete full mileage accumulation with the 
AMA cycle. The excessive time concern has been addressed in the 
proposal by the SRC which is a

[[Page 2817]]

substantially faster \24\ cycle than the AMA cycle. For that reason, 
EPA had considered eliminating the provision to allow less than full 
useful life mileage accumulation altogether. Although the provision has 
been rarely used in the past, EPA thought it would be worthwhile to 
retain it in the standard whole-vehicle durability procedure providing 
that the reduced mileage accumulation did not adversely affect the 
quality of the projected DF.
---------------------------------------------------------------------------

    \24\ The fastest allowable AMA cycle (with a top speed of 70 
MPH) has an average speed of 30.72 MPH while the SRC has an average 
speed of 46.26 MPH. The time necessary to complete 120,000 miles on 
the SRC [2594 run-hours] is less than time necessary on the AMA to 
complete 75% of the miles [90,000 miles take 2930 run-hours].
---------------------------------------------------------------------------

    It is a basic statistical principle to apply a confidence factor 
when performing projections from a limited data set. The confidence 
factor addresses the added uncertainty inherent in not generating 
actual data for the last 25% of the mileage accumulation. The one-sided 
80 percent limit is a loose requirement; it is not uncommon in 
projections to apply a confidence factor of 90% or higher. Running less 
than the full useful life mileage accumulation is voluntary.
    The need for this confidence factor is heightened now that Tier 2 
has extended useful life to a maximum of 150K miles. The idea of 
allowing the 150,000 mile useful life as an option in Tier 2 [and 
thereby avoiding compliance with the intermediate useful life 
standards] is predicated on the assumption that the added emission data 
between 120,000 and 150,000 miles would improve our statistical 
confidence that the vehicles comply with full useful life standards. If 
we now (as suggested in this comment) allow manufacturers to project 
emission compliance without considering statistical confidence when 
only 75% of useful life mileage is run, then 150,000 durability could 
be demonstrated by running only 112,500 miles. Running 75 percent of 
the 150,000 miles [112,500 miles] is actually less breadth of data than 
the normal 120,000 miles and reduces our compliance confidence rather 
than enhancing it.
    Consequently, for the reasons discussed above, EPA is adopting its 
proposal to require the use of the upper 80 percent one-sided 
statistical confidence limit when less than full mileage accumulation 
is conducted using the standard whole-vehicle durability procedure.
4. Testing Required for DF Calculation
    Summary of Proposal. If a manufacturer elects to calculate a DF, 
then it must conduct at least one FTP emission test at each of five 
different mileage points selected using good engineering judgement. The 
required testing must include testing at 5,000 miles and the highest 
mileage point run during mileage accumulation. Additional testing may 
be conducted. [Ref. 40 CFR 86.1823-08(c)(3)]
    Summary of Comments. Manufacturers should be allowed to choose the 
number of tests for DF testing on the SRC, rather than the Agency 
mandating the use of five (or more) tests at different mileage points 
as proposed.
    Response to Comments. The reason for specifying a minimum number 
and distribution of test points to be used in calculating a 
deterioration factor is to assure a minimum level of confidence in the 
result of the calculation. It is possible that the same level of 
confidence could be achieved with multiple tests conducted at a fewer 
number of discrete mileage points.
    Since the intention of this requirement was to provide a minimum 
level of confidence in the DF, another plan that results in at least as 
much confidence would equally achieve this goal. To allow greater 
flexibility in deterioration testing plans, we are adding a provision 
in the final rule that would allow other testing plans providing the 
manufacturer determines, using good engineering judgement, that the 
alternative plan would result in equivalent or superior DF confidence 
interval.
    To justify such an alternative testing plan, the manufacturer would 
need to document that the alternative testing intervals result in a DF 
confidence interval equal to or better than the confidence interval 
using the testing plan specified in the regulations [one test at 5,000 
miles, one test at full useful life mileage, and three equally spaced 
tests between 5,000 miles and the full useful life mileage].
5. Use of an Engine Dynamometer To Recreate the Aging on the SRC
    Summary of Proposal. The proposal did not specifically address what 
type of dynamometer could be used for mileage accumulation on the SRC. 
The proposed regulation simply specified use of a mileage accumulation 
dynamometer.
    Summary of Comments. Cummins commented that vehicle mileage 
accumulation on the SRC could be effectively duplicated on an engine 
dynamometer by aging the complete engine and emission control system in 
an appropriate manner. They suggested that EPA allow the use of an 
engine dynamometer as an option for whole vehicle aging.
    Response to Comments. EPA agrees with Cummins that it is possible 
to replicate the aging that occurs on the SRC by installing a complete 
engine and emission control system on an engine dynamometer and 
appropriately controlling the engine load and other parameters during 
service accumulation. Although, this option was not prohibited in the 
proposal, EPA decided to clarify the language and specifically allow 
service accumulation on a engine dynamometer as an option method to 
conduct aging following the SRC.

D. Standard Bench Aging Procedure

    Summary of Proposal. The standard bench aging procedure requires 
installation of the catalyst-plus-oxygen-sensor system on a catalyst 
aging bench. Aging on the bench is conducted by following the standard 
bench cycle (SBC) for the period of time calculated from the bench 
aging time (BAT) equation. The BAT equation requires, as input, 
catalyst time-at-temperature data measured on the SRC. This procedure 
was not applicable to diesel vehicles.
    Summary of Comments. The Alliance and AIAM commented that they 
believe that the standard bench cycle incorporates appropriate elements 
to provide an effective procedure to bench age exhaust emission 
hardware.
    Volkswagen commented that the proposed prohibition of bench aging 
procedure for use on diesel vehicles is inappropriate. The Agency 
should allow manufacturers the opportunity to propose an appropriate 
bench aging procedure for diesel vehicles which EPA would approve on a 
case-by-case basis.
    Cummins acknowledged that there is not an effective established 
procedure currently available for bench aging of diesel vehicles. 
However, they encouraged the Agency to provide some mechanism in the 
final rule that could allow approval of a bench aging procedure for 
diesels on a case-by-case basis at a later time without the need for 
further rulemaking.
    Response to Comments. Volkswagen's and Cummins suggestion that EPA 
allow a manufacturer to propose a bench aging durability procedure 
applicable to diesel vehicles without the Agency promulgating any 
description of the framework of the bench aging durability procedure 
for diesel vehicles in the regulations do not fulfill the Court's 
mandate. Nor does it fulfill the Clean Air Act requirement to establish 
methods and procedures for making

[[Page 2818]]

tests through regulation [Ref. CAA section 206 (d)].
    None of the comments take issue with EPA's conclusion that the 
proposed bench aging procedures cannot be effectively used for diesel-
fueled vehicles. The proposed bench aging procedures are designed to 
age the vehicle's catalyst-oxygen-sensor system as well as to replicate 
the total aging that occurs in use. Diesel vehicles to not employ 
catalyst technology as the principle emission control strategy, 
consequently the proposed bench aging procedure will not be effective 
for diesels. The comments did not suggest a bench aging procedure that 
was effective for diesel vehicles. In fact, Cummins acknowledged that 
there is not an effective established procedure currently available for 
bench aging of diesel vehicles.
    Consequently, EPA is retaining the proposed exclusion of diesel-
fueled vehicles from employing the bench aging procedures finalized in 
these regulations. At a later date, EPA may choose to propose 
regulations providing bench aging procedures applicable to diesel-
fueled vehicles. In the meantime, diesel-fueled vehicles must use the 
whole vehicle exhaust durability provisions.

E. Catalyst Time-at-Temperature Data Measurement

    Summary of Proposal. EPA proposed that catalyst temperature must be 
measured at the highest temperature location in the hottest catalyst on 
the DDV. Catalyst temperature must be measured at a rate of one hertz 
(one measurement per second).
    Summary of Comments. The Alliance and AIAM commented that the 
measurement rate of catalyst temperature of 1 hertz should be changed 
to allow manufacturers to determine the appropriate rate. EPA should 
not dictate the location of catalyst temperature measurements. 
Determining the worst-case location is not practical.
    Response to Comments. Both of these measurement procedures only 
apply to the standard bench procedure and its elements. Manufacturers 
may use other procedures if using a customized/alternative process that 
does not use the EPA standard BAT equation, the standard aging bench 
design (as discussed in Appendix VIII) or EPA's standard method to 
experimentally determine a customized R-factor for the BAT equation (as 
discussed in Appendix IX).
    Because the measured temperature is the basis for calculating aging 
time or determining that the appropriate amount of aging has actually 
occurred on the aging bench, it is important to carefully specify where 
to measure the temperature. Temperatures can vary by over 100 [deg]C 
between various locations in a catalyst. In developing the BAT 
equation, EPA developed the equation based on measuring the maximum 
temperature in the catalyst. EPA has been receiving catalyst 
temperature data from manufacturers for many years which was measured 
at the hottest point in the catalyst to support carryover requests or 
to evaluate durability procedure approvals under RDP-I or CAP 2000. 
Typically, manufacturers have selected measure along the central axis 
of the catalyst about one inch back of the front face. This history 
indicates to the Agency that determination of the hottest location in 
the catalyst is practical.
    In Appendix VIII, EPA proposes that the measurement of catalyst 
temperature may be either at the highest temperature location or 
another location (providing the temperature is adjusted by a linear 
transform to represent the temperature measured at the hottest catalyst 
location). To address the practicality of actual measurement, EPA has 
modified the regulation language to correspond to the appendix.
    The temperature measured in a catalyst also can change quickly over 
time during the SBC. When EPA was developing the standard bench cycle 
we used time-at-temperature data recorded at a one hertz rate. The 
temperature measured in adjacent seconds frequently is different in 
these data sets. Consequently, EPA concluded that one hertz was the 
minimum acceptable frequency rate acceptable for this purpose. Faster 
measurement would be acceptable, because it would allow for more 
accurate measurement of the changing catalyst temperature. To allow 
faster measurement, EPA has changed the regulation from the proposal to 
specify that one hertz is a minimum frequency.

F. Customized/Alternative Durability Procedures

    Summary of Proposal. Several of the comments received to the 
proposal discuss provisions that apply to different aspects of the 
customized/alternative durability procedures. As background for the 
discussion of these general comments, the following paragraphs 
summarize the provisions that were proposed for customized/alternative 
road cycles, calculation and use the equivalency factor, and 
customized/alternative bench aging durability procedures.
    Customized/Alternative Road Cycles. The Agency proposed that a 
customized or alternative road cycle could be used for certification if 
approved by the Administrator. The approval criteria require that the 
manufacturer demonstrate that whole vehicle mileage accumulation on the 
alternative/customized road cycle is expected to achieve the durability 
objective in actual use for the full range of vehicles to be covered by 
the procedure.
    The equivalency factor. The manufacturer must calculate an 
equivalency factor that equates the alternative or customized road 
cycle to the SRC run for full useful life mileage. The equivalency 
factor is used to determine how much in-use data the manufacturer must 
present in the analysis that the durability objective is expected to be 
achieved. The equivalency factor would also be made available to 
outside parties for their use to recreate aging conducted by the 
manufacturer during certification. For example, if the equivalency 
factor is 90% then the durability aging conducted by the manufacturer 
can be replicated by running the SRC for 90% of the useful life mileage 
or by bench aging using the SBC for the time calculated from the BAT 
equation using time-at-temperature data run on the SRC based on 90% of 
the useful life mileage.
    Customized/Alternative Bench Aging Durability Procedures. The 
Agency proposed that a customized or alternative bench aging procedure 
could be used for certification if approved by the Administrator. The 
proposal discussed seven types of customization allowable for the bench 
aging procedures and presented the criteria for their approval to the 
Agency. Specifically the Agency could approve the following 
customization to the standard bench aging durability procedure:
     Use a different lower-control temperature on the SBC 
providing the BAT equation was used to calculate the appropriate aging 
time.
     Use an customized R-factor in EPA's BAT equation providing 
that it is determined experimentally using the manufacturer's actual 
catalyst design.
     Use an customized A-factor in EPA's BAT equation, to 
ensure that the modified durability process will achieve the durability 
objective.
     Conduct bench aging using fuel with additional compounds 
that may lead to catalyst poisoning, such as phosphorus, sulfur or 
lead, rather than the standard fuel.
     Use an approved customized/alternative road cycle (rather 
than the

[[Page 2819]]

SRC) to develop catalyst temperature histograms for use in the BAT 
equation.
     Use a different bench cycle than the SBC with prior EPA 
approval.
     Use a different method than the standard BAT equation to 
calculate bench aging time with prior EPA approval.
1. Equivalency Factors and Alternative Road Cycles
    Summary of Comments. The Alliance and AIAM commented that it is 
pivotal that manufacturers be able to customize the standardized 
durability procedures. They support the equivalency factor approach 
because it provides the means for third parties to use the SRC to 
effectively replicate the aging effects produced by any manufacturer's 
durability protocols without requiring manufacturers to disclose 
proprietary engineering data and analysis. The equivalency factor, as 
proposed, also allows these customized/alternative procedures to be 
linked to the standard procedures. They do not object to the 
publication of the equivalency factors, themselves, but they comment 
that release of the underlying proprietary information is not required 
and is contrary to the Freedom of Information Act requirements.
    Afton (formerly known as Ethyl) commented that EPA must use 
appropriate rulemaking procedures which meet the requirements of 
section 307(d) of the CAA to adopt alternative road cycles rather than 
using the equivalency factor and the approval process discussed in the 
proposal. They acknowledge that the equivalency factor may provide a 
constructive means to attempt to balance the competing objectives of 
maintaining the secrecy of individualized certification test 
procedures, on the one hand, and disclosing to the public the test 
procedures on which the government relies to issue certification 
decisions, on the other. However, they state that the equivalency 
factor does not alter the Agency's obligation to promulgate alternative 
test procedures by regulation and include underlying data upon which 
the alternative test procedure is based. Consequently they believe that 
the proposed provision to allow the Agency to approve alternative road 
cycles does not meet the CAA requirements nor does it comply with the 
Court's mandate in Ethyl Corp. v. EPA.
    Response to Comments. We disagree with Afton's comments that the 
proposed regulations, which allow the Agency to approve alternative 
road cycles, do not meet the CAA requirements and do not comply with 
the Court's mandate in Ethyl Corp. v. EPA. The Court stated ``nothing 
in our opinion requires that EPA use only a ``one-size-fits-all'' test 
method. All that is required is that it establish its procedures, no 
matter how variegated, ``by regulation.'' That is what we have done in 
this rulemaking.
    We have established procedures that define the SRC as the standard 
whole-vehicle durability process. We have also described procedures to 
use a customized/alternative road cycle that is tied to a comparison of 
that cycle to the SRC and a demonstration that the cycle achieves the 
durability objective. In particular, the customized road cycle is the 
SRC run for a different distance. The actual distance run on a 
customized road cycle is the basis of the equivalency factor which EPA 
does not believe is confidential business information (CBI). The Agency 
plans to provide the equivalency factors to any interested party and 
post a listing on its Web site for public use.
    In the case of alternative cycles (cycles which use a different 
speed-versus-time trace than the SRC), we have also proposed (and are 
finalizing) durability procedures using those cycles. We have proposed 
procedures that specify the amount and type of data necessary for 
approval of such a cycle. We have proposed procedures that specify the 
approval method used by the Agency for approving the cycle. We have 
proposed procedures (the equivalency factor) to equate a customized 
cycle to the SRC. We have determined that the equivalency factor may be 
publically released. Furthermore, we have determined that if an outside 
party ran a vehicle on the SRC for the distance specified by the 
equivalency factor, the resulting deterioration would be equivalent to 
the manufacturer's durability showing using the customized road cycle. 
We have also proposed procedures that specify how to use the customized 
road cycle for calculating deterioration factors and/or conducting aged 
component testing. Lastly, we have proposed procedures for determining 
compliance using this data.
    In summary, in addition to the SRC, we have proposed and are 
finalizing, many details on the durability procedure for the use of 
customized road cycles. We believe we have clearly articulated a 
durability procedure (i.e., the SRC) by regulation fulfilling the 
mandate of the Court. We have also used our discretion in electing to 
describe most, but not all details, of the alternative road cycle 
durability process in the regulations. (See American Trucking 
Associations v. Department of Transportation, 166 F.3d 374 (DC Cir. 
1999) and New Mexico v. EPA, 114 F.3d 290 (DC Cir. 1997). Agencies are 
entitled to broad deference in picking the suitable level of detail to 
specify in the regulations.)
    For the above reasons, EPA is finalizing the provision to allow 
alternative road cycles approved by the Administrator as proposed.
2. Bench Durability Aging
    Summary of Comments. Afton expresses concern that whether and how 
new systems perform in the field can directly impact operation of the 
catalyst in ways that may not be captured by thermal aging. They 
specifically cite the lack of aging of certain engine and fuel system 
components. They expressed concern that the analysis presented in EPA's 
draft technical support document (TSD) for the CAP 2000 proposal, which 
shows little engine-out deterioration, may be dated. Their concern is 
based on the fact that the analysis does not include vehicles using 
certain new technology devices and strategies which may, at some future 
time, begin to appear in production but which are not used in general 
production vehicles at this time.
    The Alliance and AIAM commented that the bench aging procedures 
incorporate appropriate elements to provide an effective method to 
bench age exhaust emission hardware.
    Response to Comments. We do not share Afton's concern that the 
proposed bench aging procedures may not be sufficiently accurate for 
certification purposes. The bench aging procedures are designed to 
effectively replicate the aging that occurs during in-use operation.
    As discussed in the preamble to the proposed rule, the bench aging 
procedures are required to be adjusted to duplicate the full emission 
deterioration that occurs in-use by thermally aging the catalyst. This 
may result in over-aging the catalyst to account for emission 
deterioration that occurs from other sources. The amount of over-aging 
may be large or small. The proposed BAT equation includes a term (the 
A-factor) which is used for this purpose. EPA has set the initial value 
of A as 1.1 based on the low expected engine-out deterioration 
identified in the TSD. However, if for any cause (including unexpected 
emission control deterioration of components not aged on the aging 
bench, or based on the future technology that Afton mentions in their 
comments), the bench aging durability does not achieve the durability 
objective, EPA has proposed a requirement that manufacturers change

[[Page 2820]]

the A factor to ensure that the durability goal is appropriately 
achieved by the bench aging process. Furthermore, EPA has proposed 
requirements that the manufacturer must periodically review their 
durability process to assure that the durability object is achieved in 
actual use. To facilitate this review, EPA requires manufacturers to 
provide IUVP emission data that must be used in this evaluation 
process. Lastly, EPA can require the manufacturer to change their 
durability process if the Administrator determines that the durability 
goal is not being achieved in actual use. Consequently, any risk that 
the bench aging process may not achieve the durability goal is 
controlled by this feedback process using IUVP emission data.
    For the above reasons, EPA is finalizing the standard bench aging 
durability procedures as proposed.
3. Approval of Customized/Alternative Durability Procedures
    Summary of Comments. The Alliance and AIAM made a series of 
comments to ``eliminate unnecessary and excessive administrative 
burden''. Specifically they suggested:
    Manufacturers should be allowed to self-approve a customized/
alternative durability road cycle if they can show it is more severe 
than the SRC.
    Manufacturers should not be required to submit data from 20 in-use 
vehicles to obtain approval, rather the manufacturer should review in-
use data as it becomes available.
    The proposal requires the approval of a customized bench aging 
cycle even when the aging time is determined using the BAT equation. 
They suggest that this additional approval step is unnecessary and 
unjustified.
    EPA should eliminate all requirements for pre-approval and re-
authorization of existing durability protocols absent in-use data which 
does not meet the existing requirements.
    Response to Comments. We disagree that the approval requirements of 
the proposal are either unnecessary or excessively burdensome. EPA must 
determine to its satisfaction that a potential customized/alternative 
durability process is expected to achieve the durability goal in use. 
Most of the durability procedures approved prior to the vacature of CAP 
2000 rules were significantly changed based on the Agency's review and 
comment during the Agency's initial review. Although we now expect that 
most manufacturers have the skill necessary to design an appropriate 
customized/alternative process, we still believe that an initial review 
and approval by the Agency is still warranted.
    The proposal only requires an initial approval of the customized/
alternative durability process. Once a process is approved, the 
manufacturer must determine, using good engineering judgement, whether 
to apply the procedure to future durability groups.
    The proposal does contain provisions to require less in-use data 
for EPA approval when the customized/alternative cycle is shown to be 
significantly more severe than the SRC. We expect that approval of more 
severe cycles than the SRC to be granted, but the question still 
remains whether the customized/alternative cycle is severe enough to 
achieve the durability objective in use for the vehicles involved. 
Consequently, approval of a more severe customized/alternative cycle is 
not automatic.
    In the proposal, the amount of in-use emission data required for 
approval is varied depending whether the cycle is more or less severe 
than or approximately equivalent to the SRC. The amount of data 
required reflects the data necessary for the Agency to reach a valid 
conclusion to approve a cycle. As previously discussed, more severe 
cycles are rewarded in the approval process by a reduction in the 
amount of required data.
    The proposal requires approval of an alternative bench aging cycle 
because the distribution of air/fuel ratios and temperature is 
important to assure that adequate aging occurs. As discussed in the 
preamble to the proposed rule, a manufacturer must develop a new R 
factor if they change the bench aging cycle. Our standard R-factor 
applies only to the standard bench cycle (SBC). The determination of a 
customized R-factor is necessary because the same temperature exposure 
will result in a different amount of emission deterioration if the 
bench aging cycle is changed. The use of the standard BAT equation 
[with a different R-factor] provides no added assurance that the bench 
aging cycle will effectively replicate the emission deterioration that 
occurs on the associated road cycle as suggested in the comment. 
Consequently, EPA is finalizing the requirement to obtain Agency 
approval for alternative bench cycles.
    The proposed requirements are different than the CAP 2000 
requirements, although the durability objective has not changed. 
Pertinent facts may have changed since the approval (under the CAP 2000 
rules) of a particular durability procedure including production 
designs and the existence of more in-use data available for review. 
Although, the Agency expects that most of the durability processes that 
were approved prior to the court's vacature of the CAP 2000 rules will 
meet the requirements of this rule, we find no compelling case to make 
any blanket determination. Reviewing each durability process according 
to the new requirements on its own merits is an appropriate course of 
action for the Agency. Therefore, EPA is retaining and finalizing the 
proposed requirement that all customized/alternative durability 
procedures must be approved under the new rules (including all 
procedures used before the vacature of the CAP 2000 rules).
4. Experimentally Determining a Customized R-Factor
    Summary of the Proposal. EPA proposed that a manufacturer may 
determine an customized R-factor for use in the BAT equation. This 
would allow the BAT equation to be customized to better predict the 
required amount of bench aging necessary for a particular catalyst 
design. EPA proposed a standard experimental method for determining a 
customized R-factor in Appendix IX to the rule. EPA also proposed that 
other experimental techniques may be used if approved by the 
Administrator. To obtain approval the manufacturer must demonstrate 
that the calculated bench aging results in the same (or larger) amount 
of emission deterioration as the associated approved road cycle.
    Summary of Comments. The Alliance and AIAM commented that EPA's 
standard method for experimentally determining a R-factor [in Appendix 
IX] is overly restrictive and significantly increases the stringency of 
determining an R-factor.
    Ford commented that the approval procedure for using alternative 
techniques to experimentally determine the R-factor for the BAT 
equation should be based on accomplishing the durability objective 
rather than a comparison to the associated road cycle (the criteria in 
the proposal).
    Ford suggested an alternative standardized method to experimentally 
determine the R-factor that they felt would be more accurate and easier 
to implement. Their proposal (a detailed description is in the docket) 
suggested that emissions rather than catalyst efficiency be measured 
and that the emission deterioration projected from a least-squares 
regression of the emission versus time data be calculated directly from 
the experimental data rather than the two step process proposed by EPA.
    Response to Comments. EPA agrees that the standard method for

[[Page 2821]]

experimentally determining an R-factor supplied by Ford in their 
comments would be appropriate to use for that purpose. We also 
anticipate that it would be easier to generate the emission data 
required in Ford's alternative procedure than the conversion efficiency 
required in the proposed standard R-Factor determination procedure. 
Also this alternative approach eliminates one step compared to the 
proposed process. For those reasons, we have modified the Appendix in 
the final rule to allow this procedure.
    It should also be noted that other techniques, beyond the standard 
procedure outlined in Appendix IX to part 86, may be used as allowed in 
40 CFR 1823-08(e)(2)(iii). Ford recommended that we take a step back 
from the proposed approval criteria which require ``that the calculated 
bench aging time results in the same (or larger) amount of emission 
deterioration as the associated approved road cycle.'' They recommended 
that we require instead that the manufacturer should demonstrate that 
the use of the R-factor would achieve the durability objective. One 
concern was that the proposed text seemed to require the existence of a 
customized/alternative road cycle because this would be the only cycle 
that was ``approved'', the SRC could be used without a specific Agency 
approval.
    It was not our intention to require that a manufacturer have an 
approved customized/alternative road cycle to determine an R-factor by 
an alternative method (rather than the standard method in Appendix IX 
to Part 86). Manufacturer may also use an alternative method to 
calculate an R-Factor when using the SRC as the associated road cycle 
to measure catalyst time-at-temperature data necessary to calculate 
aging time. It is our intention however, that a manufacturer must 
generate catalyst time-at-temperature data on either the SRC or an 
approved customized/alternative road cycle. Furthermore, that an 
alternative method will only be approved if it results in the same (or 
more) aging as that associated cycle.
    We believe that the approval criteria suggested by Ford (achieving 
the durability objective) will be functionally the same as the proposed 
criteria to replicate the aging seen on the associated road cycle but 
potentially less burdensome. For an alternative bench cycle to be 
approved the manufacturer must demonstrate that it achieves the 
durability objective. However, in the case where a manufacturer is 
using the SRC, it may not have the necessary in-use emission data to 
demonstrate that durability objective is being achieved. For these 
reasons, we continue to believe that the proposed requirement is a less 
burdensome and equally effective requirement as Ford's proposal. In 
today's final regulation text we have clarified that the road cycle 
used for comparison may be either the SRC or an approved customized/
alternative cycle. Otherwise, we have finalized the alternative R-
factor methodology approval criteria as proposed.
5. Alternative Bench Aging Cycle Content
    Summary of Proposal. EPA did not propose any limitations on the 
content of an alternative bench aging cycle. EPA did propose that to 
obtain approval for such an alternative bench cycle the manufacturer 
must demonstrate that bench aging with the new bench cycle provides the 
same or larger amount of emission deterioration as the associated road 
cycle.
    Summary of Comments. The Alliance suggested that we clarify which 
provisions (in the proposed section 86.1823-08(e)(2)) pertain to 
manufacturers bench cycle and which provisions pertain to the EPA 
standard bench cycle.
    Response to Comments. EPA did not propose, nor are we finalizing, 
any limitations on the content of an alternative bench aging cycle. The 
alternative cycle may (among other differences) be of different length, 
have a different proportion of Air/Fuel ratios, different temperatures, 
different amounts of secondary air injection, and/or use no secondary 
air injection at all. However, whatever the content, the manufacturer 
must demonstrate that the alternative bench aging cycle works 
effectively by reproducing (or alternatively overstating) the aging 
that occurs on the associated road cycle which was used to measure the 
time-at-temperature data used to calculate the aging time on the aging 
bench.

G. Component Durability

    Summary of Proposal. The proposal retains the CAP 2000 requirement 
that manufacturers use good engineering judgement to determine that all 
exhaust-related components are designed to operate properly for the 
useful life of the vehicles in actual use.
    Summary of Comments. Afton argued that EPA did not meet the 
requirements of the Act or the Court's mandate in Ethyl Corp. v. EPA, 
by not proposing test methods or procedures for assessing the 
durability of emission control system components, either separately for 
components, or for all the components operating together as an 
integrated system.
    In response to this comment, the Alliance and AIAM stated that 
there is no need to implement additional ``component'' durability test 
methods and procedures because the SRC re-establishes the requisite 
threshold level of stringency for the components as well as the system 
as a whole. They also claim that the Court did not impose any 
obligation on EPA to establish a whole new regime of component 
durability tests.
    Response to Comments. While EPA believes that Afton has raised an 
important issue, the NPRM did not contemplate any revisions to the 
component durability regulations. Therefore, EPA believes that before 
taking any final action on component durability, it is appropriate to 
open this issue to further comment. Therefore, concurrent with today's 
final rule, EPA is publishing a Supplemental Notice of Rulemaking 
(SNPRM) that addresses component durability. The SNPRM will seek 
comment on several options that EPA is considering for addressing 
component durability during the vehicle emissions certification 
process. After a formal comment period, EPA will consider any further 
comments received and issue a final rule.

H. Minor Modifications to Approved Durability Procedures

    Summary of Proposal. The proposal contained a provision [ref. 
86.1823 h) (1)] that allowed a manufacturer to modify an approved 
durability procedure by increasing or decreasing the number of miles 
run on an approved road cycle to represent full or intermediate useful 
life emissions deterioration or by changing the A-Factor in the BAT 
equation for a bench aging, using good engineering judgment, to ensure 
that the modified procedure will achieve the durability objective.
    Summary of Comments. The Alliance and AIAM commented that EPA 
should restore the CAP 2000 provision that allowed manufacturers to 
make minor modifications (using good engineering judgement) to an 
approved durability procedure without the need to obtain a new approval 
from EPA.
    Response to Comments. The proposal listed only certain changes that 
the manufacturer could make to an approved durability procedure using 
good engineering judgement without obtaining approval by the 
Administrator. Those changes were increasing or decreasing the number 
of miles run on an approved road cycle or changing the A-Factor in the 
BAT

[[Page 2822]]

equation. At that time, these were the only changes that the Agency 
envisioned that could be applied to the standard EPA durability 
procedures without considering the changes to constitute a 
customization of the standard procedures that would require Agency 
approval. We also proposed that these same changes could be made to 
customized/alternative durability procedures without requiring Agency 
approval.
    We agree that allowing some level of minor adjustments or changes 
to an approved customized/alternative manufacturer durability process 
would also be appropriate if the changes were limited in scope and made 
using good engineering judgement to assure that the modified durability 
procedures would achieve the durability objective. We believe that the 
level of adjustments allowed under CAP 2000 continue to be appropriate 
in the new durability regulations. In the vacated CAP 2000 durability 
regulations we stated: (1) Such modifications will be limited to 
incorporating additional data into the original algorithms of the 
approved durability process and (2) if a manufacturer wishes to change 
the algorithms used to determine the aging characteristics of the 
durability process, these changes will be considered a new durability 
process and will require advance approval by the Administrator. 
Therefore, we have modified the final regulation language to include a 
provision for manufacturers to make these minor changes, using good 
engineering judgement, without obtaining new approval from the Agency.

I. Required Notification to EPA That an Approved Durability Procedure 
Will Be Used for a Particular Durability Group

    Summary of Proposal. The manufacturer must notify the Administrator 
of its determination to use an approved (or modified) durability 
procedure on particular test groups and durability groups prior to 
emission data vehicle testing for the affected test groups 
(notification at an annual preview meeting scheduled before the 
manufacturer begins certification activities for the model year is 
preferred).
    Summary of Comments. The Alliance and AIAM commented that the 
timing of the notification (prior to emission data vehicle testing) is 
too early in the certification process. They suggested that 
notification in the Application for Certification should be sufficient 
and is preferable to them.
    Response to Comments. The purpose of this requirement is to provide 
the Agency the necessary information about the manufacturers durability 
demonstration plans early enough in the certification process to be 
useful to the Agency. In particular, if the Agency wished to question 
the manufacturers judgement to apply a durability procedure to a 
particular durability group, it would be more efficient to raise this 
issue earlier in the certification process. Consequently, the Agency 
suggested that the notification occurs in the annual preview meeting 
which is typically scheduled before a manufacturer begins certification 
activity for a model year.
    As discussed in the current good engineering judgement provisions 
[ref. 40 CFR 86.1851-01 which is not being modified in today's final 
action] the Administrator may reject a manufacturers decision, even 
after certification is granted, if it is not based on good engineering 
judgement. Consequently, EPA agrees that notification at the time of 
the Application for Certification would provide the opportunity for 
sufficient oversight for the Agency. The risk to the manufacturer is 
that any questions regarding the good engineering decision basis of the 
manufacturers decision to apply a durability procedure to a certain 
durability group will come late in the process (or even after 
certification was granted). The good engineering judgement provisions 
in the current rule provide sufficient tools for the Agency to address 
these concerns in that time period. We still suggest that the best time 
for the notification is at the preview meeting to avoid last minute 
questions in the certification process. Nevertheless, we are changing 
the final regulation language to require the notification prior to or 
concurrently with the Application for Certification.

J. Public Availability of the Equivalency Factor and Supporting Data

    Summary of Proposal. EPA proposed methods to calculate the 
equivalency factor. EPA also stated the opinion in the proposal that 
the equivalency factor was not confidential business information (CBI) 
and it may be released to the public. EPA also announced its plan to 
post the equivalency factors on the Agency's Web site.
    Summary of Comments. The Alliance agreed with the proposal that the 
equivalency factor is not confidential and may be released to the 
public. However, they stated that manufacturers should not be compelled 
to disclose to the public any of their underlying data or other 
proprietary information used to develop their durability process.
    The Alliance and AIAM also commented that EPA should not require 
extensive engineering reports justifying equivalency factors unless 
there is in-use or other data suggesting that the manufacturer's cycle 
does not achieve the durability objective.
    They also commented that manufacturers should only be required to 
supply equivalency factors for processes that are used in the future 
(after the effective date of the proposed rules).
    Afton commented that the Court's mandate Ethyl Corp. v. EPA, 
applies to all certification decisions made since the effective date of 
the mandate. Specifically, they disagreed with the Alliance and AIAM 
comment that equivalency factor need only be supplied for new 
durability procedures approved under the proposed rules and need not be 
reported for existing durability processes that were used after the 
vacature of the CAP 2000 rules as well as aging processes that were 
approved by EPA prior to the vacature.
    Response to Comments. EPA continues to believe that the equivalency 
factor is not confidential business information and may be released to 
the public. EPA renews its intention to post the equivalency factors on 
the Agency's Web site for public use.
    We are not making any other determinations (beyond the equivalency 
factor) regarding whether other information submitted by a manufacturer 
is or is not confidential business information. These decisions to 
release other information will be made on a case-by-case basis using 
the existing regulations [Ref. 40 CFR part 2].
    We agree with Afton that the Court's mandate applies to all 
certification decisions made after the effective date of the mandate. 
However, once the Court's mandate became effective, EPA ceased 
requiring durability showings as a prerequisite to issuing a 
certificate of conformity. The basis for granting certification after 
the vacature of the CAP 2000 rule was EPA reliance on a statement made 
by the manufacturer using good engineering judgement that the vehicles 
in question will comply with the applicable standards for their full 
useful life. This statement was typically placed in the Application for 
Certification and has not generally been viewed by manufacturers as 
confidential business information. There are no approved durability 
procedures between the effective date of the Court's mandate and the 
effective date and model year of today's final rules. Consequently, 
there are no equivalency factors nor any supporting data that can be 
made

[[Page 2823]]

available by the manufacturers that apply to certification during that 
period.

K. Carryover

    Summary of Proposal. EPA did not propose any changes to the 
carryover provisions in the current regulations (ref. 40 CFR 86.1839-
01). These provisions allow manufacturers to use durability data that 
was previously generated and used to support certification provided 
that the data ``represent a worst case or equivalent rate of 
deterioration''.
    EPA proposed that the manufacturer may not, however, continue to 
use CAP 2000 durability processes to generate new data starting with 
the effective date of the new regulations. When the proposed rule 
becomes effective, manufacturers must use durability procedures that 
have been approved under the new rules to generate new durability 
demonstrations.
    Summary of Comments. The Alliance and AIAM commented that, in 
addition to allowing carry over of existing durability data prior to 
CAP 2000 vacature, manufacturers should also be allowed to use existing 
durability data employed after vacature from previously approved 
processes conforming with good engineering judgment.
    They also suggested that manufacturers should be allowed to carry 
over aging data generated after the vacature of the CAP 2000 rules 
providing that these data were compiled using aged component processes 
approved by EPA prior to the vacature.
    Lastly, they commented that manufacturers should be allowed to 
continue to use aging processes approved by EPA prior to the vacature 
to age components on future data fleet vehicles.
    Response to Comments. EPA did not propose any change to the 
carryover provisions. After the effective date of the new regulations, 
if a manufacturer can meet these requirements, it may use existing 
durability data (i.e., DFs or aged hardware). This would apply to any 
data that exists prior to the effective date of the today's regulation 
which is compiled using a durability procedure that was approved prior 
to the vacature of the CAP 2000 rules. All new data generated after the 
effective date of today's rulemaking must meet all the applicable 
requirements including the requirement that it was generated using an 
approved durability procedure.

L. Evaporative Durability Procedures

    Summary of Proposal. The proposal contained provisions for 
conducting evaporative durability using either a (1) whole vehicle 
demonstration using the SRC or another approved road cycle or a (2) 
bench aging demonstration using procedures contained in the regulations 
or (3) a combination of whole vehicle and bench procedures.
    Summary of Comments. The Alliance and AIAM commented that the 
Court's ruling dealt exclusively with tailpipe emissions and did not 
compel EPA to revisit evaporative durability.
    They also commented that separate durability demonstration for each 
evaporative family should be allowed via carryover using good 
engineering judgment.
    They also commented that EPA's right to revoke use of evaporative 
durability based on IUVP is not in keeping with CAP 2000, which said 
that EPA would use the data primarily for modeling purposes. They are 
concerned that the sample size is too small and would force 
manufacturers to ensure that IUVP evaporative emission test vehicles 
match the emission level of certification test vehicles. Non-fuel 
related emissions can not be represented in the certification 
durability process.
    Response to Comments. We disagree that the Court's decision 
regarding durability was limited to exhaust emission deterioration. 
Consequently, we proposed (and are finalizing) exhaust, evaporative, 
and refueling durability procedures.
    As discussed previously, the carryover procedures of the current 
regulations (ref. 40 CFR 86.1839-01) are not changed on the proposal. 
These provisions allow manufacturers to use durability data that was 
previously generated and used to support certification provided that 
the data ``represent a worst case or equivalent rate of 
deterioration''. Consequently, existing evaporative durability data and 
results may be carried-over providing they meet these requirements.
    We agree that the IUVP sample size (one test per test group) is too 
small to make this decision on an individual test group basis. However, 
EPA intends to review in-use evaporative data and evaluate the 
effectiveness of the durability process to achieve the durability 
objective when a reasonable amount of data does exist for this purpose. 
This expanded data set could include data from another source or it may 
consist of data combined from several related test groups or from 
several years of IUVP data. If the expanded data set indicates a 
problem, EPA believes it is appropriate to invoke this provision to re-
evaluate the manufacturer's evaporative durability procedure. 
Furthermore, if the Agency ultimately concludes that there is 
sufficient data and that the data indicate that the durability 
objective is not achieved, EPA believes it is appropriate to require 
modifications to the durability procedure in the same method used for 
exhaust emission deterioration. It would not be acceptable to continue 
to use an evaporative durability process that was demonstrated to not 
achieve the durability objective; EPA relies on the accuracy of this 
data to make appropriate decisions to grant certification. 
Consequently, we are finalizing these provisions as proposed with the 
acknowledgment that a sufficient body of data must exist to make this 
determination with appropriate confidence.

M. Starting Model Year for the Rule

    Summary of Proposal. EPA proposed that the rules would apply to 
2006 model year vehicles certified after the effective date of the 
regulations.
    Summary of Comments. The Alliance and AIAM commented that the 
proposed effective date of 2006 model year (MY) should be changed to 
2008 MY, or later if final rule published after August 2004. They 
stated that manufacturers are already doing durability testing on 2006 
models, and developmental work is already underway for early 
introduction 2007 models.
    Volkswagen commented that the effective date of 2006 MY is 
unworkable, but they do not propose an alternative date.
    Ford commented that the effective date for the regulation should be 
changed to 2009 MY if component durability issues are addressed in a 
single rulemaking and 2008 MY if the emission deterioration provisions 
are finalized separately.
    The Alliance and AIAM suggest that we add a provision allowing 
early opt-in at the manufacturer's discretion.
    Response to Comments. We agree that 2006 is no longer possible 
given the current timing for publication of the final rule. Because 
publication of the FRM has taken longer than expected, and 
manufacturers are now certifying 2006 model year vehicles and already 
performing durability testing for 2007 models, we are delaying the 
implementation of the rule to become effective beginning with the 2008 
MY.

N. Special Provisions for New Manufacturers

    Summary of Proposal. EPA did not propose any special procedures for 
new manufacturers to obtain approval of a customized/alternative 
durability procedure. However, the standard procedures may be employed 
by these

[[Page 2824]]

manufacturers without generating any in-use emission data. Also, the 
Agency did not change the special certification procedures that apply 
to small volume manufacturers (ref. 40 CFR 86.1838-01).
    Summary of Comments. The Alliance and AIAM commented that new 
manufacturers should not have to rely on IUVP data for feedback 
purposes since they supply little or no IUVP data. They suggested that 
the rule should have clear provisions for new manufacturers.
    Response to Comments. New manufacturers may use the standard 
durability procedures without submitting in-use data or obtaining EPA 
approval. We believe that these standard procedures provide a 
reasonable method for new manufacturers to supply the required 
durability data without the need to compile in-use emission data. 
However, if a new manufacturer did wish to obtain approval for a 
customized/alternative durability road cycle, EPA would accept 
appropriate data from another manufacturer's comparable in-use vehicles 
to demonstrate the effectiveness of their durability procedures to 
achieve the durability objective.

O. Delete Incorrect Reference to Intermediate Useful Life Standards for 
the Evaporative and Refueling Durability Objective

    Response to Comment. We made the appropriate correction in the 
final regulations.

P. Comments From a Private Citizen

    Summary of Comments. One citizen submitted comments that touched 
upon various topics, many of which were not germain to the proposed 
rule. In general, the consumer believed that the proposal was ``too 
friendly'' to manufacturers. The commenter requested that the public 
should always be invited to all meetings EPA has with manufacturers to 
assure that no ``secret dealings'' are taking place.
    EPA response. Some of the comments touched on issues that have been 
addressed elsewhere in this section. We disagree that the proposal was 
``too friendly'' to manufacturers. Emissions durability requirements 
impose a significant burden on manufacturers, and the provisions to 
allow for alternatives does not lessen the responsibility placed upon 
manufacturers to perform the required emission durability 
demonstration. We also disagree that all meetings with manufacturers 
should be open to the public. The discussions at these meetings center 
around individual manufacturers' business plans and are forward-looking 
in nature. Revealing these plans publicly would compromise the 
competitive automotive market. However, by informing the public of what 
sort of information is exchanged in these meetings, we believe we have 
provided the public with enough assurance that no ``deals'' are being 
made.

III. What Is EPA Promulgating Today?

    Today's final rule includes two well-defined test methods for 
determining the exhaust emissions durability of vehicles from which 
manufacturers may choose: the standard whole vehicle aging process and 
the standard bench aging process. It also includes well-defined 
criteria allowing EPA to approve customization of or alternatives to 
these test methods, based upon a demonstration to EPA of the level of 
stringency needed to meet the durability objective, and the level of 
stringency demonstrated for the SCR and the customization or 
alternative.

A. Standard Whole Vehicle Exhaust Durability Procedure

    EPA is promulgating a standard road cycle (SRC) which is targeted 
to effectively cover a significant majority of the distribution of 
exhaust emission deterioration rates that occur on candidate in-use 
vehicles. The SRC is fuel-neutral. It applies to all vehicles, 
regardless of fuel used. The SRC consists of seven laps of 3.7 miles 
each. The average speed on the SRC is 46.3 mph, the maximum cruise 
speed is 75 mph, and the acceleration rates range from light to hard 
accelerations. Most accelerations are moderate and there are no wide-
open-throttle accelerations. The SRC contains 24 fuel-cut 
decelerations. The deceleration rates range from coast-down (no brake 
force applied) to moderate.
    EPA is promulgating a standard whole vehicle durability procedure 
which consists of running a vehicle (the durability data vehicle (DDV)) 
on the SRC for the full useful life mileage of the vehicle. We are also 
finalizing rules that manufacturers may terminate mileage accumulation 
at 75% of full useful life and project DFs based upon the upper 80% 
statistical confidence limit.
    The weight of the vehicle during SRC mileage accumulation is 
proposed to be the loaded vehicle weight (curb plus 300 pounds) for 
light-duty vehicles and light light-duty trucks. The weight basis for 
SRC mileage accumulation is the adjusted loaded vehicle weight ((curb + 
gross vehicle weight)/2) for all other vehicles covered by this rule. 
The fuel used on the SRC is proposed to be representative of 
commercially available gasoline (with a provision that extra poisoning 
may be added, such as phosphorus, sulfur or lead).
    EPA is retaining the CAP 2000 options of determining emission 
compliance levels by either (1) calculating deterioration factors (DF) 
and applying the DF to the emission data vehicle (EDV) emission results 
or (2) testing the EDV with emission control components aged using the 
SRC and installed prior to testing. If DF's are to be calculated, 
emission testing would be conducted at periodic intervals during milage 
accumulation.

B. Standard Bench Aging Exhaust Durability Procedure

    Bench aging is a different way to achieve the same emission 
deterioration as whole-vehicle aging using a road cycle. EPA is 
promulgating a standard bench aging procedure that uses a bench aging 
time (BAT) equation and the standard bench cycle (SBC) to reproduce 
emission deterioration from a road cycle. EPA's standard bench 
procedure specifies that the SRC be used to generate the catalyst 
temperature histogram needed to determine bench aging time. Because the 
standard bench aging procedure relies on increasing catalyst thermal 
aging to account for all sources of emission deterioration, this 
procedure is not applicable to diesel fueled vehicles or vehicles which 
do not use a catalyst as the principal after-treatment emission control 
device.
    The standard bench aging durability procedure has been designed to 
reproduce the exhaust emission deterioration that occurs on the 
standard whole vehicle durability procedure. The standard bench aging 
procedure is as follows:
    a. Catalyst temperature data is measured at a minimum rate of one 
hertz (one measurement per second) during at least two replicates of 
the standard road cycle (SRC). The temperature results are tabulated 
into a histogram with temperature bins of no larger than 25 [deg]C.
    b. The effective reference temperature of the standard bench cycle 
(SBC), described below, is determined for the catalyst system and the 
aging bench which is to be used for the bench aging.
    c. The bench aging time is calculated using the bench aging time 
(BAT) equation, described below, using the effective reference 
temperature of the SBC and the catalyst temperature histogram measured 
on the SRC.
    d. The exhaust system (including the catalyst and oxygen sensors) 
is installed on the aging bench. The aging bench

[[Page 2825]]

follows the SBC for the amount of time calculated from the BAT 
equation.
    e. Catalyst temperatures and A/F ratios are measured during the 
bench aging process to assure that the proper amount of aging has 
actually occurred. Aging on the bench is extended if the aging targets 
are not properly achieved.
1. The Standard Bench Cycle (SBC)
    EPA is promulgating a standard bench cycle (SBC) which contains a 
mix of rich, lean and stoichiometric A/F ratios designed to achieve 
appropriate emission deterioration on the aging bench when operated for 
the period of time calculated from the BAT equation.
    The standard bench cycle consists of a 60-second cycle which is 
defined based on the A/F ratio of the engine (which is part of the 
aging bench) and the amount of secondary air injection (shop air which 
is added to the exhaust stream in front of the first catalyst).
2. The Bench-Aging Time (BAT) Calculation
    EPA is promulgating a bench aging time (BAT) equation to calculate 
the appropriate length of time to age a catalyst system on an aging 
bench to yield equivalent emission deterioration as running a vehicle 
on the associated road cycle. The standard bench aging durability 
procedure uses catalyst temperatures measured on the SRC to calculate 
the bench aging time necessary to reproduce the thermal exposure seen 
on the SRC. As discussed in the NPRM preamble, the BAT equation is 
based on the Arrehenius equation which relates chemical reaction rates 
with temperature.
3. The Effective Reference Temperature for the SBC
    The BAT equation uses a single temperature value called the 
effective reference temperature to represent the entire temperature-
history experienced during the SBC on the catalyst aging bench. The 
effective reference temperature will be calculated using catalyst 
temperature histogram data measured in the catalyst on the aging bench 
following the SBC. The BAT equation would then be used to calculate the 
effective reference temperature by iterative changes to the reference 
temperature (Tr) until the calculated aging time equaled the 
actual time representing in the catalyst temperature histogram. The 
resulting temperature is the effective reference temperature for the 
SBC.

C. Customization of the Standard Procedures

1. Customization of the Standard Road Cycle
    EPA has established criteria to obtain approval for a customized/
alternative road cycle that require the manufacturer to demonstrate 
that the objective of the durability program will be achieved for the 
breadth of the vehicles which are covered by the cycle. Approval of a 
customized/alternative road cycle requires a thorough analysis of 
whether the cycle will achieve the durability program objective using 
in-use emissions data, including a demonstration of the relative 
stringency of the SRC and the manufacturer's program.
    To make the initial demonstration necessary for the Agency to 
approve a customized/alternative cycle, EPA is requiring that the 
manufacturer supply high mileage in-use emission data on applicable 
candidate in-use vehicles. The vehicles would be randomly procured from 
actual customer use, generally with an age of 4 to 5 years and with a 
minimum of approximately 50,000 miles. They would cover the breadth of 
the vehicles that the manufacturer intends to certify using the 
customized/alternative cycle. Vehicles would be procured and FTP tested 
as received under the provisions of the IUVP program (ref: 40 CFR 
86.1845-04). Manufacturers could use previously generated in-use data 
from the CAP 2000 high mileage IUVP program or the fourth-year-of-
service RDP ``reality check'' in-use program as well as other sources 
of in-use emissions data for this purpose. EPA will also consider 
additional emissions data or analyses that the manufacturer may choose 
to provide, including data from vehicles which have been screened for 
proper maintenance and use.
    The amount of in-use emission data required for this analysis is 
based on whether the customized/alternative cycle is more or less 
severe than the SRC. In most cases, EPA will accept a minimum of 20 
candidate in-use vehicles. There is less risk of underestimating actual 
in-use emission levels when the customized/alternative cycle is more 
severe than the SRC. However, if the customized/alternative cycle is 
significantly more severe than the SRC, EPA may accept less data. 
Conversely, if the customized/alternative cycle is significantly less 
severe than the SRC, EPA may require more data up to a maximum of 30 
vehicles.
    EPA will also consider the equivalency factor of the customized/
alternative cycle when evaluating the cycle for approval.
    Once the durability process is approved, the manufacturer must 
determine, using good engineering judgement, whether to apply the 
durability procedure to a particular test group. The manufacturer may 
make modifications to an approved customized/alternative road cycle and 
apply them to a test group to ensure that the modified process will 
effectively achieve the durability objective for future candidate in-
use vehicles. The manufacturer would be required to identify such 
changes in its certification application and explain the basis for the 
changes. Manufacturers must use good engineering judgement in making 
these decisions. Significant, major, or fundamental changes to a 
customized/alternative cycle would be considered new cycles and would 
require advance approval by EPA.
2. Customization of Standard Bench Procedures
    The manufacturers are allowed, subject to Agency approval, a 
limited degree of customization of the standard bench procedures. 
However, in all cases EPA is requiring that alternative bench aging 
procedures be based upon measured vehicle performance (such as catalyst 
temperature) on an approved road cycle.
    Specifically EPA is allowing customization of any or all of the 
following parameters when the accompanying conditions for approval are 
met:
    a. The lower control temperature on the SBC may be modified without 
prior EPA approval provided that the high control temperature is set 90 
[deg]C ( 10 [deg]C) above the lower control temperature and 
an approved BAT equation is used to calculate bench aging time.
    b. The R-factor used in EPA's BAT equation may be determined 
experimentally using EPA's standard procedures (specified in the 
appendix to the regulations) without prior EPA approval. Other 
experimental techniques to calculate the R-factor require advance EPA 
approval. To obtain approval, the manufacturer must demonstrate that 
the calculated bench aging time results in the same (or larger) amount 
of emission deterioration as the associated road cycle.
    c. The A-factor used in EPA's BAT equation may be modified, using 
good engineering judgement without prior EPA approval, to ensure that 
the modified durability process will achieve the durability objective 
(discussed previously).

[[Page 2826]]

    d. Bench-aging may be conducted using fuel with additional poisons 
(such as phosphorus, sulfur and lead) without prior EPA approval. Using 
fuel with additional poisons is worst case for emissions deterioration. 
Normally a manufacturer using fuel with additional poisons will either 
calculate a new R-factor or A-factor to assure that the durability 
objective is properly achieved.
    e. An approved alternative road cycle or customized SRC may be used 
to develop catalyst temperature histograms for use in the BAT equation 
without additional EPA approval beyond the original approval necessary 
to use the road cycle for mileage accumulation.
    f. A different bench cycle may be used during bench aging with 
prior EPA approval. To obtain approval the manufacturer must 
demonstrate that bench aging with the new bench cycle provides the same 
(or larger) amount of emission deterioration as the associated road 
cycle.
    g. A different method to calculate bench aging time may be used 
with prior EPA approval. To obtain approval the manufacturer must 
demonstrate that bench aging for the time calculated by the alternative 
method results in the same (or larger) amount of emission deterioration 
as the associated road cycle.
3. Reproducibility by Outside Parties
    EPA is finalizing the provision that an alternative road cycle must 
be designed to achieve the durability objective. As part of this 
evaluation, EPA is requiring that all alternative road cycles are 
equated to the SRC by means of an equivalency factor that determines 
the amount of SRC-driving that results in the same emission 
deterioration as the alternative cycle. EPA is requiring that every 
alternative bench aging procedure be based upon measured vehicle 
performance on an approved road cycle. Lastly, EPA is requiring that 
any alternative bench cycle be designed to result in the same levels of 
emission deterioration as the road cycle upon which it was based.
    An important element of the regulation is that, regardless of 
whether a manufacturer uses the EPA standard procedures or customized 
procedures, any interested party will be able to use the equivalency 
factor to reproduce the amount of emission deterioration produced by 
any manufacturer's customized/alternative durability process used 
during vehicle certification. Any alternative road or bench procedure 
is equated to a given number of miles on the SRC.
    To reproduce the deterioration generated by a customized/
alternative road cycle, standard bench procedure, or alternative bench 
procedure, an outside party may run a vehicle using the SRC for the 
number of miles indicated by the equivalency factor.
    Similarly, an outside party will be able to perform bench aging 
using the SBC. The aging time may be calculated using the BAT equation 
and measured catalyst temperature on the SRC (with full-useful-life-
mileage adjusted by the equivalency factor).

D. Using IUVP Data To Improve Durability Predictions

    Manufacturers are required to review their durability program and 
prepare an analysis for EPA evaluation when: (1) The IUVP emission 
levels exceed the applicable certification emission standard 50% or 
more of the test vehicles and (2) the average emission level is at 
least 1.3 times the applicable emission standard. These criteria would 
be evaluated independently for all applicable FTP emission 
constituents. Each constituent should be considered separately in this 
analysis.
    The Agency may, from time to time, require manufacturers to analyze 
available IUVP data, or other information, when it indicates that the 
durability objective is not being achieved for some portion of the 
fleet of vehicles covered by a durability procedure. This provision 
would apply whether or not the screening criteria are exceeded.
    As in the CAP 2000 program, EPA may withdraw approval of a 
durability program or require its modification if it determines that 
the program does not meet the objectives for a durability program. The 
Agency will give the manufacturer a preliminary notice at least 60 days 
prior to rendering a final decision to withdraw approval for or require 
modifications to a durability procedure. During this period the 
manufacturer may submit technical discussion, statistical analyses, 
additional data, or other information that is relevant to the decision. 
This may include an analysis to determine whether factors other than 
the durability program, such as part defects, are the source of the 
problem. The Administrator will consider all information submitted by 
the deadline before reaching a final decision. A final decision to 
withdraw approval or require modification to a durability procedure 
would apply to future applications for certification and to the portion 
of the manufacturer's product line (or the entire product line) that 
the Administrator determines to be affected.
    If the manufacturer was using the standard road cycle or standard 
bench cycle, EPA will require the manufacturer to adjust the durability 
process so it would achieve the durability objective. The Agency will 
allow two options in this situation: (1) Increasing future DFs by the 
average percent-difference between certification levels and IUVP data, 
or (2) increasing the whole vehicle miles driven or catalyst aging time 
by the average percent-difference between certification levels and IUVP 
data. Additionally the manufacturer may obtain approval for a new 
alternative durability process that has been demonstrated to meet the 
durability objective. If the data set used in the analysis contains 
less than 20 pieces of data, the Administrator may reduce the degree of 
adjustment required to account for uncertainty in the data.

E. Evaporative and Refueling Durability

    EPA is finalizing provisions that require manufacturers determine 
the evaporative/refueling deterioration using either whole vehicle 
durability or bench aging methods or a combination of the two methods.
    Whole Vehicle Evaporative/Refueling Durability. Manufacturers may 
conduct evaporative and/or refueling durability program by running the 
DDV on the SRC or an approved alternative road cycle and conducting the 
applicable test at each testing point. Manufacturers may combine 
exhaust and evaporative/refueling whole vehicle durability 
demonstrations.
    Bench-Aging Evaporative/Refueling Durability. Manufacturers may use 
bench procedures designed, using good engineering judgement, to 
evaluate the following potential causes of evaporative emission 
deterioration and achieve the durability objective:
    (1) Cycling of canister loading due to diurnal and refueling 
events,
    (2) Use of various commercially available fuels, including the Tier 
2 requirement to include alcohol fuel;
    (3) Vibration of components;
    (4) Deterioration of hoses, etc. due to environmental conditions; 
and
    (5) Deterioration of fuel cap due to wear.
    Manufacturers will determine evaporative and refueling DFs using 
good engineering judgement without the need for prior EPA approval.

F. Compliance Date and Carryover of Existing Durability Data

    Manufacturers must meet the requirements of today's action 
beginning with the 2008 model year.

[[Page 2827]]

    EPA is not making any changes to the carryover provisions in the 
current regulations (ref. 40 CFR 86.1839-01). These provisions allow 
manufacturers to use durability data that was previously generated and 
used to support certification provided that the data ``represent a 
worst case or equivalent rate of deterioration''. Beginning in the 2008 
model year, if a manufacturer can meet these requirements, it may use 
existing durability data (i.e., DFs or aged hardware) to support 
certification.
    The manufacturer may not, however, continue to use CAP 2000 
durability processes to generate new data starting with the 2008 model 
year. When the proposed rule becomes effective in the 2008 model year, 
manufacturers must use durability procedures that have been approved 
under the new rules to generate new durability demonstrations.

G. Miscellaneous Regulatory Amendments and Corrections

    1. With the addition of the new durability regulations (sections 
86.1823-08, 86.1824-08, and 86.1825-08), the regulatory references in a 
number of other sections of subpart S of part 86 have been updated 
accordingly.
    2. Section 1864 of subpart S is being moved to section 1801. This 
section describes the applicability of subpart S to heavy-duty 
vehicles, and is more appropriately located in the Applicability 
section of the regulations.
    3. An outdated address in section 1817-05 has been corrected.
    4. A typographical error in section 1830-01(c) has been corrected.
    5. Two corrections are being made to section 86.1806-05, on-board 
diagnostics. First, in a previous regulatory action, this section was 
amended to add provisions for diesel vehicles and HDVs and MDPVs. In 
doing this, an inadvertent error was made in paragraph (a)(3). The 
provision allowing compliance with 86.004-17, in lieu of 1806-05, 
should be limited to apply only to MDPVs and HDVs. The language has 
been revised accordingly. Second, in the original CAP 2000 regulation, 
there is an incorrect reference to section 86.094-17(e) and (f). The 
correct reference is 1806-05(e) and (f).

IV. What Are the Economic and Environmental Impacts?

A. Economic Impacts

1. Comparison to CAP 2000 Economic Impacts
    In considering the economic and environmental impacts of today's 
proposal, we used the CAP 2000 regulations as a comparison benchmark. 
In those regulations, EPA estimated that there would be an average 
annual net savings to the automotive industry of about $55 million. The 
analysis performed to reach that conclusion was part of the record for 
the CAP 2000 regulation, and was not contested.
    In today's final rulemaking, one of our goals was to retain those 
savings. In the CAP 2000 cost analysis, about half of the total 
estimated annual savings was attributed to the durability component of 
the regulations. The elements of CAP 2000 durability which provided the 
most significant savings are:
    a. Reduced number of durability data vehicles (DDVs). The creation 
of the ``durability group'' under CAP 2000 allowed manufacturers to 
significantly reduce the number of required durability demonstrations. 
The savings that are claimed in the CAP 2000 rule resulting from the 
``durability group'' provision come from requiring physically fewer 
DDVs, fewer durability tests, and less reporting (e.g. instead of 
having to report 912 durability tests, there would only be 620 tests). 
The ``durability group'' concept was not part of the Ethyl v. EPA 
litigation, nor was it mentioned in the Court's opinion on this case. 
Thus EPA is not modifying the ``durability group'' regulations in 
today's final rule.
    In fact, it is possible that today's final rule could actually 
slightly reduce some costs to the industry, in that manufacturers using 
one of the EPA-prescribed durability processes (either whole-vehicle or 
bench) would no longer have to provide a description of their 
durability process (which was required under CAP 2000, and would 
continue to be required for manufacturers using customized procedures 
under today's final rule).
    b. Reduced burden-hours per DDV. In addition to fewer DDVs, in the 
CAP 2000 rulemaking, EPA also slightly reduced the estimated number of 
burden-hours required per DDV. As above, this element was not affected 
by the Court mandate, and is not impacted by today's final rule.
2. Economic Impact of Today's Rule
    Today's final rule prescribes two methods for determining the 
emission deterioration of vehicles over their useful life periods--the 
whole-vehicle procedure or the bench-aging procedure. Details of how to 
perform these procedures are prescribed in the proposed regulations. 
Because these procedures are similar in nature to those approved by EPA 
under the CAP 2000 regulations, the added burden for manufacturers 
utilizing them will be minimal.\25\ The costs involved with either of 
these processes (equipment costs, vehicle costs, testing costs, labor 
costs, etc.) are fairly fixed. Manufacturers using one of the 
prescribed methods will not be required to make major changes to or add 
any new equipment, test any additional vehicles with any additional 
frequency, or to increase the amount of labor. We expect that 
manufacturers who, under the old CAP 2000 regulations, used a bench-
aging (or whole-vehicle) process will continue to use a bench-aging (or 
whole-vehicle) process--the only difference is that now that process is 
codified.
---------------------------------------------------------------------------

    \25\ Added burden will be in the form of the one-time 
reprogramming of automated driving or bench-aging devices with the 
new driving/aging cycle, and other minor equipment adjustments.
---------------------------------------------------------------------------

    The final regulations also include the option for manufacturers to 
use customized or alternative procedures, with EPA approval. The 
approval requires the manufacturer to submit an analysis of about 20 
in-use emission tests. Most manufacturers will be able to utilize in-
use data and analyses that they have previously collected from other 
sources (such as the CAP 2000 in-use verification data). Some 
manufacturers may need to augment this data by running a few additional 
tests, but this would be a small, one-time cost. EPA estimates that 
this small added cost is more than offset by the fact that once 
approved, manufacturers will be able to use their durability programs 
without the need to make any changes to those programs.
    As discussed above, EPA is issuing a separate Supplemental Notice 
of Proposed Rulemaking which addresses component durability. Any costs 
associated with that proposal will be addressed in that notice.

B. Environmental Impacts

    In the CAP 2000 rule, no quantifiable environmental benefits were 
projected. Intangible benefits were possible due to the In-Use 
Verification Program (IUVP) element of the CAP 2000 rule--manufacturers 
would be able to use the in-use data from this program to identify and 
fix in-use compliance problems and to make improvements upon their 
certification durability processes. This intangible benefit is not 
changed in today's final rule--the in-use verification program is not 
affected by the Court mandate, and no changes to this program are being 
proposed. EPA is modifying an existing CAP 2000 provision whereby 
manufacturers utilize the IUVP data to assess the ability of the 
durability program to

[[Page 2828]]

predict in-use compliance. The modification includes more explicit 
instructions as to what the manufacturer is required to assess and when 
corrective action is required (see section III C.). This proposed 
provision will have the effect of improving the predictive qualities of 
the durability process, but again, with intangible environmental 
benefits.

VI. What Are the Statutory and Executive Order Reviews for This 
Proposed Rule?

A. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order 12866 (58 FR 51735 October 4, 1993), EPA must 
determine whether the regulatory action is ``significant'' and 
therefore subject to Office of Management and Budget (OMB) review and 
the requirements of this 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, OMB has notified 
EPA that it considers this a ``significant regulatory action'' within 
the meaning of the Executive Order. OMB has waived review of this 
action.

B. Paperwork Reduction Act

    This action does not impose any new information collection burden 
under the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et 
seq. However, the Office of Management and Budget (OMB) has previously 
approved the information collection requirements contained in the 
existing regulations (64 FR 23906) under the provisions of the 
Paperwork Reduction Act, 44 U.S.C. 3501 et seq. and has assigned OMB 
control number 2060-0104, EPA ICR number 0783.44. A copy of the OMB 
approved Information Collection Requests (ICR) may be obtained from 
Susan Auby, Collection Strategies Division; U.S. Environmental 
Protection Agency (2822T); 1200 Pennsylvania Ave., NW., Washington, DC 
20460 or by calling (202) 566-1672.
    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.

C. Regulatory Flexibility Analysis

    EPA has determined that it is not necessary to prepare a regulatory 
flexibility analysis in connection with this final rule.
    For purposes of assessing the impacts of today's rule on small 
entities, small entity is defined as: (1) A small business as defined 
by the Small Business Administrations' regulations at 13 CFR 121.201; 
(2) a small governmental jurisdiction that is a government of a city, 
county, town, school district or special district with a population of 
less than 50,000; and (3) a small organization that is any not-for-
profit enterprise which is independently owned and operated and is not 
dominant in its field.
    After considering the economic impacts of today's final rule on 
small entities, EPA has concluded that this action will not have a 
significant economic impact on a substantial number of small entities. 
A small business that manufacturers automobiles has a NAIC code of 
336111. Based on Small Business Administration size standards, a small 
business for this NAIC code is defined as a manufacturer having less 
than 1000 employees. The requirements are only applicable to 
manufacturers of motor vehicles, a group which does not contain a 
substantial number of small entities. Out of a total of approximately 
80 automotive manufacturers subject to today's proposal, EPA estimates 
that approximately 15-20 of these could be classified as small entities 
based on SBA size standards. EPA's CAP 2000 compliance regulations 
include numerous regulatory relief provisions for such small entities. 
Those provisions remain in effect and are not impacted by today's final 
rule.

D. 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 action on state, local, and tribal 
governments and the private sector. Under section 202 of the UMRA, EPA 
generally must prepare a written statement, including a cost-benefit 
analysis, for proposed and proposed rules with ``Federal mandates'' 
that may result in expenditures by state, local, and tribal 
governments, in the aggregate, or by the private sector, of $100 
million or more in any one year. Before promulgation 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 proposed 
rule an explanation why that alternative was not adopted.
    Before we establish any regulatory requirement that may 
significantly or uniquely affect small governments, including tribal 
governments, we must develop, 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 
our regulatory proposals with significant federal intergovernmental 
mandates. The plan must also provide for informing, educating, and 
advising small governments on compliance with the regulatory 
requirements.
    EPA believes this final rule contains no Federal mandates for 
state, local, or tribal governments. Nor does this rule have federal 
mandates that may result in the expenditures of $100 million or more in 
any year by the private sector as defined by the provisions of Title II

[[Page 2829]]

of the UMRA. Nothing in the final rule would significantly or uniquely 
affect small governments.

E. Executive Order 13132 (Federalism)

    Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' is defined in the 
Executive Order to include regulations that have ``substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government.''
    This final rule will impose no direct compliance costs on states. 
Thus, Executive Order 13132 does not apply to this rule.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    Executive Order 13175, entitled ``Consultation and Coordination 
with Indian Tribal Governments'' (65 FR 67249, November 6, 2000), 
requires EPA to develop an accountable process to ensure ``meaningful 
and timely input by tribal officials in the development of regulatory 
policies that have tribal implications.'' ``Policies that have tribal 
implications'' is defined in the Executive Order to include regulations 
that have ``substantial direct effects on one or more Indian tribes, on 
the relationship between the Federal government and the Indian tribes, 
or on the distribution of power and responsibilities between the 
Federal government and Indian tribes.''
    This final rule does not have tribal implications. It will not have 
substantial direct effects on tribal governments, on the relationship 
between the Federal government and Indian tribes, or on the 
distribution of power and responsibilities between the Federal 
government and Indian tribes, as specified in Executive Order 13175. 
The requirements of this action impact private sector businesses, 
particularly the automotive and engine manufacturing industries. Thus, 
Executive Order 13175 does not apply to this rule.

G. Executive Order 13045: Children's Health Protection

    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 E.O. 13045 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 E.O. 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. This final rule is not subject to E.O. 13045 
because it is based on technology performance and not on health or 
safety risks.

H. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    This rule is not subject to Executive Order 13211, ``Actions 
Concerning Regulations That Significantly Affect Energy Supply, 
Distribution, or Use'' (66 FR 28355, May 22, 2001) because it is not a 
significant regulatory action under Executive Order 12866.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law 104-113, 12(d) (15 U.S.C. 272), directs 
the EPA to use voluntary consensus standards (VCS) in its regulatory 
activities unless to do so would be inconsistent with applicable law or 
otherwise impractical. Voluntary consensus standards are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, business practices, etc.) that are developed or adopted by 
voluntary consensus standard bodies. The NTTAA requires EPA to provide 
Congress, through OMB, explanations when the Agency decides not to use 
available and applicable voluntary consensus standards.
    This final rule does not involve consideration of any new technical 
standards. The durability test procedures that EPA is adopting are 
unique and have not been previously published in the public domain.

J. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as amended by 
the Small Business Regulatory Enforcement Fairness Act of 1996, 
generally provides that before a rule may take effect, the agency 
promulgating the rule must submit a rule report, which includes a copy 
of the rule, to Congress and the comptroller General of the United 
States. We will submit a report containing this rule and other required 
information to the U.S. Senate, the U.S. House of Representatives, and 
the Comptroller General of the United States prior to publication of 
the rule in the Federal Register. A major rule cannot take effect until 
60 days after it is published in the Federal Register. This action is 
not a ``major rule'' as defined by 5 U.S.C. 804(2).

List of Subjects in 40 CFR Part 86

    Environmental protection, Air pollution control, Motor vehicle 
pollution, Confidential business information, Reporting and 
recordkeeping requirements.

    Dated: December 29, 2005.
Stephen Johnson,
Administrator.

0
For the reasons set forth in the preamble, The Environmental Protection 
Agency title 40, chapter I of the Code of Federal Regulations is 
amended as follows:

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

0
1. The authority citation for part 86 continues to read as follows:

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

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

0
2. Amend Sec.  86.1803-01 by adding a new definition in alphabetical 
order, to read as follows:


Sec.  86.1803-01  Definitions.

* * * * *
    Secondary air injection means a system whereby air (not ingested by 
the engine) is introduced into the exhaust system in front of a 
catalyst.
* * * * *

0
3. Amend Sec.  86.1804-01 by adding new acronyms in alphabetical order, 
to read as follows:


Sec.  86.1804-01  Acronyms and abbreviations.

* * * * *
A/F--Air/Fuel
* * * * *
BAT--Bench-Aging Time
* * * * *

[[Page 2830]]

SBC--Standard Bench Cycle
* * * * *
SRC--Standard Road Cycle
* * * * *

0
4. Amend Sec.  86.1817-05 by revising paragraph (i)(3)(i) to read as 
follows:


Sec.  86.1817-05  Complete heavy-duty vehicle averaging, trading, and 
banking program.

* * * * *
    (i) * * *
    (3) * * *
    (i) These reports shall be submitted within 90 days of the end of 
the model year to: Director, Certification and Compliance Division, 
U.S. Environmental Protection Agency, Mail Code 6405J, 1200 
Pennsylvania Ave., NW., 20460.
* * * * *

0
5. Add a new Sec.  86.1823-08 subpart S to read as follows:


Sec.  86.1823-08  Durability demonstration procedures for exhaust 
emissions.

    This section applies to all 2008 and later model year vehicles 
which meet the applicability provisions of Sec.  86.1801. Optionally, a 
manufacturer may elect to use this section for earlier model year 
vehicles which meet the applicability provisions of Sec.  86.1801. 
Eligible small volume manufacturers or small volume test groups may 
optionally meet the requirements of Sec. Sec.  86.1838-01 and 86.1826-
01 in lieu of the requirements of this section. A separate durability 
demonstration is required for each durability group.
    (a) Durability program objective. The durability program must 
predict an expected in-use emission deterioration rate and emission 
level that effectively represents a significant majority of the 
distribution of emission levels and deterioration in actual use over 
the full and intermediate useful life of candidate in-use vehicles of 
each vehicle design which uses the durability program.
    (b) Required durability demonstration. Manufacturers must conduct a 
durability demonstration for each durability group using a procedure 
specified in either paragraph (c), (d), or (e) of this section.
    (c) Standard whole-vehicle durability procedure. This procedure 
consists of conducting mileage accumulation and periodic testing on the 
durability data vehicle, selected under the provisions of Sec.  86.1822 
described as follows:
    (1) Mileage accumulation must be conducted using the standard road 
cycle (SRC). The SRC is described in Appendix V of this part.
    (i) Mileage accumulation on the SRC may be conducted on a track or 
on a chassis mileage accumulation dynamometer. Alternatively, the 
entire engine and emission control system may be aged on an engine 
dynamometer using methods that will replicate the aging that occurs on 
the road for that vehicle following the SRC.
    (ii) The fuel used for mileage accumulation must comply with the 
mileage accumulation fuel provisions of Sec.  86.113 for the applicable 
fuel type (e.g., gasoline or diesel fuel).
    (iii) The DDV must be ballasted to a minimum of the loaded vehicle 
weight for light-duty vehicles and light light-duty trucks and a 
minimum of the ALVW for all other vehicles.
    (iv) The mileage accumulation dynamometer must be setup as follows:
    (A) The simulated test weight will be the equivalent test weight 
specified in Sec.  86.129 using a weight basis of the loaded vehicle 
weight for light-duty vehicles and ALVW for all other vehicles.
    (B) The road force simulation will be determined according to the 
provisions of Sec.  86.129.
    (C) The manufacturer will control the vehicle, engine, and/or 
dynamometer as appropriate to follow the SRC using good engineering 
judgement.
    (2) Mileage accumulation must be conducted for at least 75% of the 
applicable full useful life mileage period specified in Sec.  86.1805. 
If the mileage accumulation is less than 100% of the full useful life 
mileage, then the DF calculated according to the procedures of 
paragraph (f)(1)(ii) of this section must be based upon a line 
projected to the full-useful life mileage using the upper 80 percent 
statistical confidence limit calculated from the emission data.
    (3) If a manufacturer elects to calculate a DF pursuant to 
paragraph (f)(1) of this section, then it must conduct at least one FTP 
emission test at each of five different mileage points selected using 
good engineering judgement. Additional testing may be conducted by the 
manufacturer using good engineering judgement. The required testing 
must include testing at 5,000 miles and at the highest mileage point 
run during mileage accumulation (e.g. the full useful life mileage). 
Different testing plans may be used providing that the manufacturer 
determines, using good engineering judgement, that the alternative plan 
would result in an equivalent or superior level of confidence in the 
accuracy of the DF calculation compared to the testing plan specified 
in this paragraph.
    (d) Standard bench-aging durability procedure. This procedure is 
not applicable to diesel fueled vehicles or vehicles which do not use a 
catalyst as the principle after-treatment emission control device. This 
procedure requires installation of the catalyst-plus-oxygen-sensor 
system on a catalyst aging bench. Aging on the bench is conducted by 
following the standard bench cycle (SBC) for the period of time 
calculated from the bench aging time (BAT) equation. The BAT equation 
requires, as input, catalyst time-at-temperature data measured on the 
SRC.
    (1) Standard bench cycle (SBC). Standard catalyst bench aging is 
conducted following the SBC
    (i) The SBC must be run for the period of time calculated from the 
BAT equation.
    (ii) The SBC is described in Appendix VII to Part 86.
    (2) Catalyst time-at-temperature data
    (i) Catalyst temperature must be measured during at least two full 
cycles of the SRC.
    (ii) Catalyst temperature must be measured at the highest 
temperature location in the hottest catalyst on the DDV. Alternatively, 
the temperature may be measured at another location providing that it 
is adjusted to represent the temperature measured at the hottest 
location using good engineering judgement.
    (iii) Catalyst temperature must be measured at a minimum rate of 
one hertz (one measurement per second).
    (iv) The measured catalyst temperature results must be tabulated 
into a histogram with temperature bins of no larger than 25[deg] C.
    (3) Bench-aging time. Bench aging time is calculated using the 
bench aging time (BAT) equation as follows:

te for a temperature bin = th 
e((R/Tr)-(R/Tv))
Total te = Sum of te over all the temperature 
bins
Bench-Aging Time = A (Total te )


Where:

A = 1.1 This value adjusts the catalyst aging time to account for 
deterioration from sources other than thermal aging of the catalyst.
R = Catalyst thermal reactivity coefficient. For the SBC, R=17500 for 
Tier 2 vehicles and R=18500 for all other vehicles.
th = The time (in hours) measured within the prescribed 
temperature bin of the vehicle's catalyst temperature histogram 
adjusted to a full useful life basis e.g., if the histogram represented 
400 miles, and full useful life was 100,000 miles; all histogram time 
entries would be multiplied by 250 (100000/400).
Total te = The equivalent time (in hours) to age the 
catalyst at the temperature of Tr on the catalyst aging 
bench using the catalyst aging cycle to produce the

[[Page 2831]]

same amount of deterioration experienced by the catalyst due to thermal 
deactivation over the vehicle's full useful life.
te for a bin = The equivalent time (in hours) to age the 
catalyst at the temperature of Tr on the catalyst aging 
bench using the catalyst aging cycle to produce the same amount of 
deterioration experienced by the catalyst due to thermal deactivation 
at the temperature bin of Tv over the vehicle's full useful 
life.
Tr = The effective reference temperature (in [deg]K) of the 
catalyst on the catalyst bench run on the bench aging cycle. The 
effective temperature is the constant temperature that would result in 
the same amount of aging as the various temperatures experienced during 
the bench aging cycle.
Tv = The mid-point temperature (in [deg]K) of the 
temperature bin of the vehicle on-road catalyst temperature histogram.

    (4) Effective reference temperature on the SBC. The effective 
reference temperature of the standard bench cycle (SBC) is determined 
for the actual catalyst system design and actual aging bench which will 
be used using the following procedures:
    (i) Measure time-at-temperature data in the catalyst system on the 
catalyst aging bench following the SBC.
    (A) Catalyst temperature must be measured at the highest 
temperature location of the hottest catalyst in the system. 
Alternatively, the temperature may be measured at another location 
providing that it is adjusted to represent the temperature measured at 
the hottest location using good engineering judgement.
    (B) Catalyst temperature must be measured at a minimum rate of one 
hertz (one measurement per second) during at least 20 minutes of bench 
aging.
    (C) The measured catalyst temperature results must be tabulated 
into a histogram with temperature bins of no larger than 10[deg] C.
    (ii) The BAT equation must be used to calculate the effective 
reference temperature by iterative changes to the reference temperature 
(Tr) until the calculated aging time equals the actual time 
represented in the catalyst temperature histogram. The resulting 
temperature is the effective reference temperature on the SBC for that 
catalyst system and aging bench.
    (5) Catalyst Aging Bench. The manufacturer must design, using good 
engineering judgement, a catalyst aging bench that follows the SBC and 
delivers the appropriate exhaust flow, exhaust constituents, and 
exhaust temperature to the face of the catalyst.
    (i) A manufacturer may use the criteria and equipment discussed in 
Appendix VIII to part 86 to develop its catalyst aging bench without 
prior Agency approval. The manufacturer may use another design that 
results in equivalent or superior results with advance Agency approval.
    (ii) All bench aging equipment and procedures must record 
appropriate information (such as measured A/F ratios and time-at-
temperature in the catalyst) to assure that sufficient aging has 
actually occurred.
    (6) Required Testing. If a manufacturer is electing to calculate a 
DF (as discussed in paragraph (f)(1) of this section), then it must 
conduct at least two FTP emissions tests on the DDV before bench aging 
of emission control hardware and at least two FTP emission tests on the 
DDV after the bench-aged emission hardware is re-installed. Additional 
testing may be conducted by the manufacturer using good engineering 
judgement.
    (e) Additional durability procedures--(1) Whole vehicle durability 
procedures. A manufacturer may use either a customized SRC or an 
alternative road cycle for the required durability demonstration, with 
prior EPA approval.
    (i) Customized SRC. A customized SRC is the SRC run for a different 
number of miles and/or using a different mileage accumulation fuel with 
higher levels of certain compounds that may lead to catalyst poisoning, 
such as phosphorus, sulfur and lead, than specified in paragraph 
(c)(1)(ii) of this section.
    (ii) Alternative Road Cycle. An alternative cycle is a whole 
vehicle mileage accumulation cycle that uses a different speed-versus-
time trace than the SRC, conducted for either the full useful life 
mileage or for less than full useful life mileage. An alternative road 
cycle may also include the use of fuel with higher levels of certain 
compounds that may lead to catalyst poisoning, such as phosphorus, 
sulfur and lead, than specified in paragraph (c)(1)(ii) of this 
section.
    (iii) Approval Criteria. The manufacturer must obtain approval from 
EPA prior to using a customized/alternative road cycle. EPA may approve 
a customized/alternative cycle when the manufacturer demonstrates that 
the cycle is expected to achieve the durability program objective of 
paragraph (a) of this section for the breadth of vehicles using the 
customized/alternative cycle. To obtain approval the manufacturer must 
submit all the following information and perform all the following 
analyses:
    (A) The manufacturer must supply in-use FTP emission data on past 
model year vehicles which are applicable to the vehicle designs it 
intends to cover with the customized/alternative cycle.
    (1) The amount of in-use emission data required to demonstrate the 
effectiveness of a customized/alternative cycle in meeting the 
durability objective is based on whether the customized/alternative 
cycle is more or less severe than the SRC. In most cases, EPA will 
accept a minimum of 20 candidate in-use vehicles tested as-received on 
the FTP cycle. If the customized/alternative cycle is significantly 
more severe than the SRC, EPA may accept less data. Conversely, if the 
customized/alternative cycle is significantly less severe than the SRC, 
EPA may require more data, up to a maximum of 30 vehicles.
    (2) This data set must consist of randomly procured vehicles from 
actual customer use. The vehicles selected for procurement must cover 
the breadth of the vehicles that the manufacturer intends to certify 
using the customized/alternative cycle. Vehicles should be procured and 
FTP tested in as-received condition under the guidelines of the high 
mileage IUVP program (ref: 40 CFR 86.1845-04).
    (3) Manufacturers may use previously generated in-use data from the 
CAP 2000 IUVP or the RDP ``reality check'' in-use program as well as 
other sources of in-use emissions data for approval under this section.
    (4) Manufacturers must remove unrepresentative data from the data 
set using good engineering judgement. The manufacturer must provide EPA 
with the data removed from the analysis and a justification for the 
removal of that data.
    (5) Manufacturers may supply additional in-use data.
    (B) The manufacturer must submit an analysis which includes a 
comparison of the relative stringency of the customized/alternative 
cycle to the SRC and a calculated equivalency factor for the cycle.
    (1) The equivalency factor may be determined by an evaluation of 
the SRC and the customized/alternative cycle using catalyst time-at-
temperature data from both cycles and the BAT equation to calculate the 
required bench aging time of each cycle. The equivalency factor is the 
ratio of the aging time on the SRC divided by the aging time on the 
alternative cycle.
    (2) If emissions data is available from the SRC, as well as time-
at-temperature data, then that emissions information

[[Page 2832]]

may be included in the evaluation of the relative stringency of the two 
cycles and the development of the equivalency factor.
    (3) A separate equivalency factor may be determined for each test 
group, or test groups may be combined together (using good engineering 
judgement) to calculate a single equivalency factor.
    (C) The manufacturer must submit an analysis which evaluates 
whether the durability objective will be achieved for the vehicle 
designs which will be certified using the customized/alternative cycle. 
The analysis must address of the following elements:
    (1) How the durability objective has been achieved using the data 
submitted in paragraph (e)(1)(iii)(A) of this section.
    (2) How the durability objective will be achieved for the vehicle 
designs which will be covered by the customized/alternative cycle. This 
analysis should consider the emissions deterioration impact of the 
design differences between the vehicles included in the data set 
required in (e)(1)(iii)(A) of this section and the vehicle designs that 
the manufacturer intends to certify using the customized/alternative 
cycle.
    (2) Bench-aging durability procedures. A manufacturer may use a 
customized or alternative bench aging durability procedure for a 
required durability demonstration, if approved as described in 
paragraphs (e)(2)(i) through (vii) of this section. A customized/
alternative bench aging procedure must use vehicle performance data 
(such as catalyst temperature) measured on an approved road cycle as 
part of the algorithm to calculate bench aging time. The manufacturer 
must obtain approval from the Agency prior to using a customized bench 
durability procedure.
    (i) The lower control temperature on the SBC may be modified 
without prior EPA approval provided that the high control temperature 
is set 90 [deg]C above the lower control temperature and an approved 
BAT equation is used to calculate bench aging time.
    (ii) The R-factor used in EPA's BAT equation may be determined 
experimentally using EPA's standard procedures (specified in Appendix 
IX of this part) without prior EPA approval. Other experimental 
techniques to calculate the R-factor require advance EPA approval. To 
obtain approval, the manufacturer must demonstrate that the calculated 
bench aging time results in the same (or larger) amount of emission 
deterioration as the associated road cycle.
    (iii) The A-factor used in EPA's BAT equation may be modified, 
using good engineering judgement without prior EPA approval, to ensure 
that the modified durability process will achieve the durability 
objective of paragraph (a) of this section.
    (iv) Bench aging may be conducted using fuel with additional 
compounds that may lead to catalyst poisoning, such as phosphorus, 
sulfur or lead, without prior EPA approval. A manufacturer using fuel 
with these additional compounds may either calculate a new R-factor or 
A-factor to assure that the durability objective of paragraph (a) of 
this section is properly achieved regardless of the use of worst-case 
fuel, in which case the approval criteria for those changes would 
apply.
    (v) An approved customized/alternative road cycle may be used to 
develop catalyst temperature histograms for use in the BAT equation 
without additional EPA approval beyond the original approval necessary 
to use that cycle for mileage accumulation.
    (vi) A different bench cycle than the SBC may be used during bench 
aging with prior EPA approval. To obtain approval the manufacturer must 
demonstrate that bench aging for the appropriate time on the new bench 
cycle provides the same or larger amount of emission deterioration as 
the associated road cycle.
    (vii) A different method to calculate bench aging time may be used 
with prior EPA approval. To obtain approval the manufacturer must 
demonstrate that bench aging for the time calculated by the alternative 
method results in the same or larger amount of emission deterioration 
as the associated road cycle.
    (f) Use of deterioration program to determine compliance with the 
standard. A manufacturer may select from two methods for using the 
results of the deterioration program to determine compliance with the 
applicable emission standards. Either a deterioration factor (DF) is 
calculated and applied to the emission data vehicle (EDV) emission 
results or aged components are installed on the EDV prior to emission 
testing.
    (1) Deterioration factors.
    (i) Deterioration factors are calculated using all FTP emission 
test data generated during the durability testing program except as 
noted:
    (A) Multiple tests at a given mileage point are averaged together 
unless the same number of tests are conducted at each mileage point.
    (B) Before and after maintenance test results are averaged 
together.
    (C) Zero-mile test results are excluded from the calculation.
    (D) Total hydrocarbon (THC) test points beyond the 50,000-mile 
(useful life) test point are excluded from the intermediate useful life 
deterioration factor calculation.
    (E) A procedure may be employed to identify and remove from the DF 
calculation those test results determined to be statistical outliers 
providing that the outlier procedure is consistently applied to all 
vehicles and data points and is approved in advance by the 
Administrator.
    (ii) The deterioration factor must be based on a linear regression, 
or another regression technique approved in advance by the 
Administrator. The deterioration must be a multiplicative or additive 
factor. Separate factors will be calculated for each regulated emission 
constituent and for the full and intermediate useful life periods as 
applicable. Separate DF's are calculated for each durability group 
except as provided in Sec.  86.1839.
    (A) A multiplicative DF will be calculated by taking the ratio of 
the full or intermediate useful life mileage level, as appropriate 
(rounded to four decimal places), divided by the stabilized mileage 
(reference Sec.  86.1831-01(c), e.g., 4000-mile) level (rounded to four 
decimal places) from the regression analysis. The result must be 
rounded to three-decimal places of accuracy. The rounding required in 
this paragraph must be conducted in accordance with Sec.  86.1837. 
Calculated DF values of less than one must be changed to one for the 
purposes of this paragraph.
    (B) An additive DF will be calculated to be the difference between 
the full or intermediate useful life mileage level (as appropriate) 
minus the stabilized mileage (reference Sec.  86.1831-01(c), e.g. 4000-
mile) level from the regression analysis. The full useful life 
regressed emission value, the stabilized mileage regressed emission 
value, and the DF result must be rounded to the same precision and 
using the same procedures as the raw emission results according to the 
provisions of Sec.  86.1837-01. Calculated DF values of less than zero 
must be changed to zero for the purposes of this paragraph.
    (iii) The DF calculated by these procedures will be used for 
determining full and intermediate useful life compliance with FTP 
exhaust emission standards, SFTP exhaust emission standards, and cold 
CO emission standards. At the manufacturer's option and using 
procedures approved by the Administrator, a separate DF may be 
calculated exclusively using cold CO test data to determine compliance 
with cold CO emission standards. Also at the manufacturer's option and 
using procedures approved by the Administrator, a separate DF may be

[[Page 2833]]

calculated exclusively using US06 and/or air conditioning (SC03) test 
data to determine compliance with the SFTP emission standards.
    (2) Installation of aged components on emission data vehicles. For 
full and intermediate useful life compliance determination, the 
manufacturer may elect to install aged components on an EDV prior to 
emission testing rather than applying a deterioration factor. Different 
sets of components may be aged for full and intermediate useful life 
periods. Components must be aged using an approved durability procedure 
that complies with paragraph (b) of this section. The list of 
components to be aged and subsequently installed on the EDV must 
selected using good engineering judgement.
    (g) Emission component durability. [Reserved] For guidance see 40 
CFR 86.1823-01(e).
    (h) Application of the durability procedure to future durability 
groups. The manufacturer may apply a durability procedure approved 
under paragraphs (c), (d) or (e) of this section to a durability group, 
including durability groups in future model years, if the durability 
process will achieve the objective of paragraph (a) of this section for 
that durability group. The manufacturer must use good engineering 
judgment in determining the applicability of an approved durability 
procedure to a durability group.
    (1) Modifications to a durability procedure.
    (i) Standard durability procedures. The manufacturer may modify a 
standard durability procedure (allowed in paragraphs (c) or (d) of this 
section) by increasing or decreasing the number of miles run on the SRC 
to represent full or intermediate useful life emissions deterioration 
or by changing the A-Factor in the BAT equation for a bench aging, 
using good engineering judgment, to ensure that the modified procedure 
will achieve the objective of paragraph (a) of this section for that 
durability group.
    (ii) Customized/Alternative durability procedures. The manufacturer 
may modify an alternative/customized durability procedure approved 
under the provisions of paragraph (e) of this section, using good 
engineering judgment, for the purposes of ensuring that the modified 
procedure will achieve the objective of paragraph (a) of this section 
for that durability group.
    (2) The manufacturer must notify the Administrator of its 
determination to use an approved (or modified) durability procedure on 
particular test groups and durability groups prior to, or concurrently 
with, its submission of the Application for Certification for the 
affected test groups (notification at an annual preview meeting 
scheduled before the manufacturer begins certification activities for 
the model year is preferred).
    (3) Prior to certification, the Administrator may reject the 
manufacturer's determination in paragraph (h) of this section to apply 
an approved or modified durability procedure for a durability group or 
test group if:
    (i) It is not made using good engineering judgment,
    (ii) It fails to properly consider data collected under the 
provisions of Sec. Sec.  86.1845-04, 86.1846-01, and 86.1847-01 or 
other information, or
    (iii) The Administrator determines that the durability procedure 
has not been shown to achieve the objective of paragraph (a) of this 
section for particular test groups which the manufacturer plans to 
cover with the durability procedure.
    (i) Evaluation of the certification durability procedures based on 
in-use emissions data.
    (1) Manufacturers must use the information gathered from the IUVP, 
as well as other sources of in-use emissions data, to periodically 
review whether the durability procedure it employs achieves the 
objective specified in paragraph (a) of this section.
    (2) Required analysis of a manufacturer's approved durability 
procedures.
    (i) In addition to any periodic reviews under paragraph (i)(1) of 
this section, a manufacturer must conduct a review of whether the 
durability procedure it employs achieves the durability objective 
specified in paragraph (a) of this section when the criteria for 
additional testing specified in Sec.  86.1846 (b) are activated.
    (ii) These criteria are evaluated independently for all applicable 
FTP emission constituents.
    (iii) This analysis must be performed for each test group certified 
by the manufacturer.
    (iv) These procedures apply to the EPA standard durability 
procedures discussed in paragraphs (c) and (d) of this section as well 
as durability procedures approved under paragraph (e) of this section, 
including modifications under paragraph (h) of this section.
    (v) The analysis must be submitted to EPA no later than 60 days 
after the submission of the IUVP data report specified in Sec.  
86.1847(f).
    (3) EPA may require a manufacturer to perform an analysis as 
described in paragraph (i)(2) of this section if EPA is concerned that 
the manufacturer's durability procedure may not achieve the durability 
objective of paragraph (a) of this section.
    (j) If, based on the analysis required in paragraph (i) of this 
section and/or any other information, EPA determines that the 
durability procedure does not achieve the durability objective of 
paragraph (a) of this section, EPA may withdraw approval to use the 
durability procedure or condition approval on modifications to the 
durability procedure. Such withdrawal or conditional approval will 
apply to future applications for certification and to the portion of 
the manufacturer's product line (or the entire product line) that the 
Administrator determines to be affected. Prior to such a withdrawal the 
Administrator will give the manufacturer a preliminary notice at least 
60 days prior to the final decision. During this period, the 
manufacturer may submit technical discussion, statistical analyses, 
additional data, or other information which is relevant to the 
decision. The Administrator will consider all information submitted by 
the deadline before reaching a final decision.
    (k) If EPA withdraws approval, under the provisions of paragraph 
(j) of this section, for a durability procedure approved under the 
provisions of paragraphs (c) and/or (d) of this section, the following 
procedures apply:
    (1) The manufacturer must select one of the following options for 
future applications for certification for the applicable portion of the 
manufacturers product-line affect by the Agency's decision:
    (i) Increase future DFs calculated using the applicable durability 
process by the average percent-difference between certification levels 
and IUVP data; or
    (ii) Increase the miles driven on the SRC or the aging time 
calculated by the BAT equation by the average percent-difference 
between certification levels and IUVP data, or
    (iii) The manufacturer may obtain approval for a new customized 
durability process, as allowed in paragraph (e) of this section, that 
has been demonstrated to meet the durability objective.
    (2) If EPA's decision to withdraw approval under the provisions of 
paragraph (j) of this section is based on fewer than 20 tests, the 
Administrator may require a smaller adjustment than specified in 
paragraph (k)(1)(i) or (ii) of this section.
    (l) Any manufacturer may request a hearing on the Administrator's

[[Page 2834]]

withdrawal of approval in paragraphs (j) or (k) of this section. The 
request must be in writing and must include a statement specifying the 
manufacturer's objections to the Administrator's determinations, and 
data in support of such objection. If, after review of the request and 
supporting data, the Administrator finds that the request raises a 
substantial factual issue, she/he must provide the manufacturer a 
hearing in accordance with Sec.  86.1853-01 with respect to such issue.

0
6. Add Sec.  86.1824-08 to subpart S to read as follows:


Sec.  86.1824-08  Durability demonstration procedures for evaporative 
emissions.

    This section applies to gasoline-, methanol-, liquefied petroleum 
gas-, and natural gas-fueled 2008 and later model year vehicles which 
meet the applicability provisions of Sec.  86.1801. Optionally, a 
manufacturer may elect to use this section for earlier model year 
gasoline-, methanol-, liquefied petroleum gas-, and natural gas-fueled 
vehicles which meet the applicability provisions of Sec.  86.1801. 
Eligible small volume manufacturers or small volume test groups may 
optionally meet the requirements of Sec. Sec.  86.1838-01 and 86.1826-
01 in lieu of the requirements of this section. A separate durability 
demonstration is required for each evaporative/refueling family.
    (a) Durability program objective. The durability program must 
predict an expected in-use emission deterioration rate and emission 
level that effectively represents a significant majority of the 
distribution of emission levels and deterioration in actual use over 
the full useful life of candidate in-use vehicles of each vehicle 
design which uses the durability program.
    (b) Required durability demonstration. Manufacturers must conduct a 
durability demonstration which satisfies the provisions of either 
paragraph (c), (d), or (e) of this section.
    (c) Whole vehicle evaporative durability demonstration.
    (1) Mileage accumulation must be conducted using the SRC or any 
road cycle approved under the provisions of Sec.  86.1823(e)(1).
    (2) Mileage accumulation must be conducted for either:
    (i) The applicable full useful life mileage period specified in 
Sec.  86.1805, or
    (ii) At least 75 percent of the full useful life mileage. In which 
case, the manufacturer must calculate a df calculated according to the 
procedures of paragraph (f)(1)(ii) of this section, except that the DF 
must be based upon a line projected to the full-useful life mileage 
using the upper 80 percent statistical confidence limit calculated from 
the emission data.
    (3) The manufacturer must conduct at least one evaporative emission 
test at each of the five different mileage points selected using good 
engineering judgement. The required testing must include testing at 
5,000 miles and at the highest mileage point run during mileage 
accumulation (e.g. the full useful life mileage). Additional testing 
may be conducted by the manufacturer using good engineering judgement. 
The manufacturer may select to run either the 2-day and/or 3-day 
evaporative test at each test point using good engineering judgement.
    (d) Bench aging evaporative durability procedures. Manufacturers 
may use bench procedures designed, using good engineering judgement, to 
evaluate the emission deterioration of evaporative control systems. 
Manufacturers may base the bench procedure on an evaluation the 
following potential causes of evaporative emission deterioration:
    (1) Cycling of canister loading due to diurnal and refueling 
events,
    (2) Use of various commercially available fuels, including the Tier 
2 requirement to include alcohol fuel;
    (3) Vibration of components;
    (4) Deterioration of hoses, etc. due to environmental conditions; 
and
    (5) Deterioration of fuel cap due to wear.
    (e) Combined whole-vehicle and bench-aging programs. Manufacturers 
may combine the results of whole vehicle aging and bench aging 
procedures using good engineering judgement.
    (f) Fuel requirements.
    (1) For gasoline fueled vehicles certified to meet the evaporative 
emission standards set forth in Sec.  86.1811-04(e)(1), any mileage 
accumulation method for evaporative emissions must employ gasoline fuel 
for the entire mileage accumulation period which contains ethanol in, 
at least, the highest concentration permissible in gasoline under 
federal law and that is commercially available in any state in the 
United States. Unless otherwise approved by the Administrator, the 
manufacturer must determine the appropriate ethanol concentration by 
selecting the highest legal concentration commercially available during 
the calendar year before the one in which the manufacturer begins its 
mileage accumulation. The manufacturer must also provide information 
acceptable to the Administrator to indicate that the mileage 
accumulation method is of sufficient design, duration and severity to 
stabilize the permeability of all non-metallic fuel and evaporative 
system components to the mileage accumulation fuel constituents.
    (2) For flexible-fueled, dual-fueled, multi-fueled, ethanol-fueled 
and methanol-fueled vehicles certified to meet the evaporative emission 
standards set forth in Sec.  86.1811-04(e)(1), any mileage accumulation 
method must employ fuel for the entire mileage accumulation period 
which the vehicle is designed to use and which the Administrator 
determines will have the greatest impact upon the permeability of 
evaporative and fuel system components. The manufacturer must also 
provide information acceptable to the Administrator to indicate that 
the mileage accumulation method is of sufficient design, duration and 
severity to stabilize the permeability of all non-metallic fuel and 
evaporative system components to mileage accumulation fuel 
constituents.
    (3) A manufacturer may use other methods, based upon good 
engineering judgment, to meet the requirements of paragraphs (f)(1) and 
(2) of this section, as applicable. These methods must be approved in 
advance by the Administrator and meet the objectives of paragraphs 
(f)(1) and (2) of this section, as applicable: to provide assurance 
that the permeability of all non-metallic fuel and evaporative system 
components will not lead to evaporative emission standard exceedance 
under sustained exposure to commercially available alcohol-containing 
fuels for the useful life of the vehicle.
    (g) Calculation of a deterioration factor. The manufacturer must 
calculate a deterioration factor which is applied to the evaporative 
emission results of the emission data vehicles. The deterioration 
factor must be based on a linear regression, or an other regression 
technique approved in advance by the Administrator. The DF will be 
calculated to be the difference between the full life mileage 
evaporative level minus the stabilized mileage (e.g., 4000-mile) 
evaporative level from the regression analysis. The full useful life 
regressed emission value, the stabilized mileage regressed emission 
value, and the DF result must be rounded to the same precision and 
using the same procedures as the raw emission results according to the 
provisions of Sec.  86.1837-01. Calculated DF values of less than zero 
must be changed to zero for the purposes of this paragraph.
    (h) Emission component durability. [Reserved] For guidance see 40 
CFR 86.1824-01(d).
    (i) If EPA determines based on IUVP data or other information that 
the

[[Page 2835]]

durability procedure does not achieve the durability objective of 
paragraph (a) of this section, EPA may withdraw approval to use the 
durability procedure or condition approval on modifications to the 
durability procedure. Such withdrawal or conditional approval will 
apply to future applications for certification and to the portion of 
the manufacturer's product line (or the entire product line) that the 
Administrator determines to be affected. Prior to such a withdrawal the 
Administrator will give the manufacturer a preliminary notice at least 
60 days prior to the final decision. During this period, the 
manufacturer may submit technical discussion, statistical analyses, 
additional data, or other information which is relevant to the 
decision. The Administrator will consider all information submitted by 
the deadline before reaching a final decision.
    (j) Any manufacturer may request a hearing on the Administrator's 
withdrawal of approval in paragraph (i) of this section. The request 
must be in writing and must include a statement specifying the 
manufacturer's objections to the Administrator's determinations, and 
data in support of such objection. If, after review of the request and 
supporting data, the Administrator finds that the request raises a 
substantial factual issue, she/he must provide the manufacturer a 
hearing in accordance with Sec.  86.1853-01 with respect to such issue.

0
7. Add a new Sec.  86.1825-08 to Subpart S to read as follows:


Sec.  86.1825-08  Durability demonstration procedures for refueling 
emissions.

    This section applies to 2008 and later model year light-duty 
vehicles, light-duty trucks, and heavy-duty vehicles which are 
certified under light-duty rules as allowed under the provisions of 
Sec.  86.1801-01(c)(1) which are subject to refueling loss emission 
compliance. Optionally, a manufacturer may elect to use this section 
for earlier model year light-duty vehicles, light-duty trucks, and 
heavy-duty vehicles which are certified under light-duty rules as 
allowed under the provisions of Sec.  86.1801-01(c)(1) which are 
subject to refueling loss emission compliance. Refer to the provisions 
of Sec. Sec.  86.1811, 86.1812, 86.1813, 86.1814, and 86.1815 to 
determine applicability of the refueling standards to different classes 
of vehicles for various model years. Diesel fuel vehicles may qualify 
for an exemption to the requirements of this section under the 
provisions of Sec.  86.1810.
    (a) Durability program objective. The durability program must 
predict an expected in-use emission deterioration rate and emission 
level that effectively represents a significant majority of the 
distribution of emission levels and deterioration in actual use over 
the full useful life of candidate in-use vehicles of each vehicle 
design which uses the durability program.
    (b) Required durability demonstration. Manufacturers must conduct a 
durability demonstration which satisfies the provisions of either 
paragraph (c), (d), or (e) of this section.
    (c) Whole vehicle refueling durability demonstration. The following 
procedures must be used when conducting a whole vehicle durability 
demonstration:
    (1) Mileage accumulation must be conducted using the SRC or a road 
cycle approved under the provisions of Sec.  86.1823(e)(1).
    (2) Mileage accumulation must be conducted for either:
    (i) The applicable full useful life mileage period specified in 
Sec.  86.1805, or
    (ii) At least 75 percent of the full useful life mileage. In which 
case, the manufacturer must calculate a df calculated according to the 
procedures of paragraph (f)(1)(ii) of this section, except that the DF 
must be based upon a line projected to the full-useful life mileage 
using the upper 80 percent statistical confidence limit calculated from 
the emission data.
    (3) The manufacturer must conduct at least one refueling emission 
test at each of the five different mileage points selected using good 
engineering judgement. The required testing must include testing at 
5,000 miles and at the highest mileage point run during mileage 
accumulation (e.g. the full useful life mileage). Additional testing 
may be conducted by the manufacturer using good engineering judgement.
    (d) Bench aging refueling durability procedures. Manufacturers may 
use bench procedures designed, using good engineering judgement, to 
evaluate the emission deterioration of evaporative/refueling control 
systems. Manufacturers may base the bench procedure on an evaluation 
the following potential causes of evaporative/refueling emission 
deterioration:
    (1) Cycling of canister loading due to diurnal and refueling 
events;
    (2) Use of various commercially available fuels, including the Tier 
2 requirement to include alcohol fuel;
    (3) Vibration of components;
    (4) Deterioration of hoses, etc. due to environmental conditions; 
and
    (5) Deterioration of fuel cap due to wear.
    (e) Combined whole-vehicle and bench-aging programs. Manufacturers 
may combine the results of whole vehicle aging and bench aging 
procedures using good engineering judgement.
    (f) [Reserved]
    (g) Calculation of a deterioration factor. The manufacturer must 
calculate a deterioration factor which is applied to the evaporative 
emission results of the emission data vehicles. The deterioration 
factor must be based on a linear regression, or an other regression 
technique approved in advance by the Administrator. The DF will be 
calculated to be the difference between the full life mileage 
evaporative level minus the stabilized mileage (e.g., 4000-mile) 
evaporative level from the regression analysis. The full useful life 
regressed emission value, the stabilized mileage regressed emission 
value, and the DF result must be rounded to the same precision and 
using the same procedures as the raw emission results according to the 
provisions of Sec.  86.1837-01. Calculated DF values of less than zero 
must be changed to zero for the purposes of this paragraph.
    (h) Emission component durability. [Reserved] For guidance see 40 
CFR 86.1845-01 (e).
    (i) If EPA determines based on IUVP data or other information that 
the durability procedure does not achieve the durability objective of 
paragraph (a) of this section, EPA may withdraw approval to use the 
durability procedure or condition approval on modifications to the 
durability procedure. Such withdrawal or conditional approval will 
apply to future applications for certification and to the portion of 
the manufacturer's product line (or the entire product line) that the 
Administrator determines to be affected. Prior to such a withdrawal the 
Administrator will give the manufacturer a preliminary notice at least 
60 days prior to the final decision. During this period, the 
manufacturer may submit technical discussion, statistical analyses, 
additional data, or other information which is relevant to the 
decision. The Administrator will consider all information submitted by 
the deadline before reaching a final decision.
    (j) Any manufacturer may request a hearing on the Administrator's 
withdrawal of approval in paragraph (i) of this section. The request 
must be in writing and must include a statement specifying the 
manufacturer's objections to the Administrator's determinations, and 
data in support of such objection.

[[Page 2836]]

If, after review of the request and supporting data, the Administrator 
finds that the request raises a substantial factual issue, she/he must 
provide the manufacturer a hearing in accordance with Sec.  86.1853-01 
with respect to such issue.

0
8. Amend Sec.  86.1826-01 by revising paragraphs (a) and (b)(3)(iv) to 
read as follows:


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

    (a) Applicability. This program is an option available to small 
volume manufacturers certified under the small volume manufacturer 
provisions of Sec.  86.1838-01(b)(1) and small volume test groups 
certified under the small volume test group provisions of Sec.  
86.1838-01(b)(2). Manufacturers may elect to use these procedures in 
lieu of the requirements of Sec. Sec.  86.1823, 86.1824, and 86.1825 of 
this subpart.
    (b) * * *
    (3) * * *
    (iv) The manufacturer must develop either deterioration factors or 
aged components to use on EDV testing by generating durability data in 
accordance with Sec. Sec.  86.1823, 86.1824, and/or 86.1825 on a 
minimum of 25 percent of the manufacturer's projected sales (based on 
durability groups) that is equipped with unproven emission control 
systems.
* * * * *

0
9. Amend Sec.  86.1829-01 by revising paragraphs (a)(3) and (d)(1) to 
read as follows:


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

    (a) * * *
    (3) The DDV shall be tested and accumulate service mileage 
according to the provisions of Sec. Sec.  86.1831-01, 86.1823, 86.1824 
and 86.1825. Small volume manufacturers and small volume test groups 
may optionally meet the requirements of Sec.  86.1838-01.
* * * * *
    (d)(1) Beginning in the 2004 model year, the exhaust emissions must 
be measured from all LDV/T exhaust emission data vehicles tested in 
accordance with the federal Highway Fuel Economy Test (HWFET; 40 CFR 
part 600, subpart B). The oxides of nitrogen emissions measured during 
such tests must represent the full useful life emissions in accordance 
with Sec.  86.1823-08(f) and subsequent model year provisions. Those 
results are then rounded and compared with the applicable emission 
standard in Sec.  86.1811-04. All data obtained from the testing 
required under this paragraph (d) must be reported in accordance with 
the procedures for reporting other exhaust emission data required under 
this subpart.
* * * * *

0
10. Amend Sec.  86.1830-01 by revising paragraphs (b)(1), (b)(2), 
(c)(1), (c)(2), (c)(3) and (c)(4) to read as follows:


Sec.  86.1830-01  Acceptance of vehicles for emission testing.

* * * * *
    (b) Special provisions for durability data vehicles. (1) For DDV's, 
the mileage at all test points shall be within 250 miles of the 
scheduled mileage point as required under Sec.  86.1823-08(c)(3). 
Manufacturers may exceed the 250 mile upper limit if there are 
logistical reasons for the deviation and the manufacturer determines 
that the deviation will not affect the representativeness of the 
durability demonstration.
    (2) For DDV's aged using the standard or a customized/alternative 
whole-vehicle cycle, all emission-related hardware and software must be 
installed and operational during all mileage accumulation after the 
5000-mile test point.
* * * * *
    (c) Special provisions for emission data vehicles. (1) All EDV's 
shall have at least the minimum number of miles accumulated to achieve 
stabilized emission results according to the provisions of Sec.  
86.1831-01(c).
    (2) Within a durability group, the manufacturer may alter any 
emission data vehicle (or other vehicles such as current or previous 
model year emission data vehicles, running change vehicles, fuel 
economy data vehicles, and development vehicles) in lieu of building a 
new test vehicle providing that the modification will not impact the 
representativeness of the vehicle's test results. Manufacturers shall 
use good engineering judgment in making such determinations. 
Development vehicles which were used to develop the calibration 
selected for emission data testing may not be used as the EDV for that 
configuration. Vehicles from outside the durability group may be 
altered with advance approval of the Administrator.
    (3) Components used to reconfigure EDV's under the provisions of 
paragraph (c)(2) of this section must be appropriately aged if 
necessary to achieve representative emission results. Manufacturers 
must determine the need for component aging and the type and amount of 
aging required using good engineering judgment.
    (4) Bench-aged hardware may be installed on an EDV for emission 
testing as a method of determining certification levels (projected 
emission levels at full or intermediate useful life) using bench aging 
procedures under the provisions of Sec.  86.1823.

0
11. Amend Sec.  86.1831-01 by revising paragraphs (a)(1) and (b)(1) to 
read as follows:


Sec.  86.1831-01  Mileage accumulation requirements for test vehicles.

    (a) Durability Data Vehicles. (1) The manufacturer must accumulate 
mileage on DDV's using the procedures in Sec.  86.1823.
    (b) * * *
    (1) The standard method of mileage accumulation for emission data 
vehicles and running change vehicles is mileage accumulation using 
either the Standard Road Cycle specified in Appendix V to this part or 
the Durability Driving Schedule specified in Appendix IV to this part.
* * * * *

0
12. Amend Sec.  86.1838-01 by revising paragraph (c)(1) to read as 
follows:


Sec.  86.1838-01  Small volume manufacturers certification procedures.

* * * * *
    (c) * * *
    (1) Durability demonstration. Use the provisions of Sec.  86.1826-
01 rather than the requirements of Sec. Sec.  86.1823, 86.1824, and/or 
86.1825.
* * * * *

0
13. Amend Sec.  86.1839-01 by revising paragraph (b) to read as 
follows:


Sec.  86.1839-01  Carryover of certification data.

* * * * *
    (b) In lieu of using newly aged hardware on an EDV as allowed under 
the provisions of Sec.  86.1823-08(f)(2), a manufacturer may use 
similar hardware aged for an EDV previously submitted, provided that 
the manufacturer determines that the previously aged hardware 
represents a worst case or equivalent rate of deterioration for all 
applicable emission constituents for durability demonstration.
0
14. Amend Sec.  86.1841-01 by revising paragraphs (a)(1) introductory 
text and (a)(2) and removing and reserving paragraph (a)(3) to read as 
follows:


Sec.  86.1841-01  Compliance with emission standards for the purpose of 
certification.

    (a) * * *
    (1) If the durability demonstration procedure used by the 
manufacturer under the provisions of Sec. Sec.  86.1823, 86.1824, or 
86.1825 requires a DF to be calculated, the DF shall be applied to the 
official test results determined in Sec.  86.1835-01(c) for each 
regulated

[[Page 2837]]

emission constituent and for full and intermediate useful life, as 
appropriate, using the following procedures:
* * * * *
    (2) If the durability demonstration procedure used by the 
manufacturer under the provisions of Sec. Sec.  86.1823, 86.1824, or 
86.1825, as applicable, requires testing of the EDV with aged emission 
components, the official results of that testing determined under the 
provisions of Sec.  86.1835-01(c) shall be rounded to the same level of 
precision as the standard for each regulated constituent at full and 
intermediate useful life, as appropriate. This rounded emission value 
is the certification level for that emission constituent at that useful 
life mileage.
    (3) [Reserved]
* * * * *

0
15. Amend Sec.  86.1844-01 by revising paragraph (d)(4) to read as 
follows:


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

* * * * *
    (d) * * *
    (4) Durability information.
    (i) A description of the durability method used to establish useful 
life durability, including exhaust and evaporative/refueling emission 
deterioration factors as required in Sec. Sec.  86.1823, 86.1824 and 
86.1825 when applicable.
    (ii) The equivalency factor required to be calculated in Sec.  
1823-06(e)(iii)(B), when applicable.
* * * * *

0
16. Add Appendices V, VII, VIII, and IX to part 86 to read as follows:

Appendix V to Part 86--The Standard Road Cycle (SRC)

    1. The standard road cycle (SRC) is a mileage accumulation cycle 
that may be used for any vehicle which is covered by the 
applicability provisions of Sec.  86.1801. The vehicle may be run on 
a track or on a mileage accumulation dynamometer.
    2. The cycle consists of 7 laps of a 3.7 mile course. The length 
of the lap may be changed to accommodate the length of the service-
accumulation track.

                         Description of the SRC
------------------------------------------------------------------------
                                                               Typical
           Lap                        Description             accel rate
                                                               (MPH/s)
------------------------------------------------------------------------
1........................  (start engine) Idle 10 sec......            0
1........................  Mod accel to 30 MPH.............            4
1........................  Cruise at 30 MPH for \1/4\ lap..            0
1........................  Mod. decel to 20 MPH............           -5
1........................  Mod accel to 30 MPH.............            4
1........................  Cruise at 30 MPH for \1/4\ lap..            0
1........................  Mod. decel to stop..............           -5
1........................  Idle 5 sec......................            0
1........................  Mod accel to 35 MPH.............            4
1........................  Cruise at 35 MPH for \1/4\ lap..            0
1........................  Mod. decel to 25 MPH............           -5
1........................  Mod accel to 35 MPH.............            4
1........................  Cruise at 35 MPH for \1/4\ lap..            0
1........................  Mod. decel to stop..............           -5
--------------------------
2........................  Idle 10 sec.....................            0
2........................  Mod accel to 40 MPH.............            3
2........................  Cruise at 40 MPH for \1/4\ lap..            0
2........................  Mod. decel to 30 MPH............           -5
2........................  Mod accel to 40 MPH.............            3
2........................  Cruise at 40 MPH for \1/4\ lap..            0
2........................  Mod. decel to stop..............           -5
2........................  Idle 5 sec......................            0
2........................  Mod accel to 45 MPH.............            3
2........................  Cruise at 45 MPH for \1/4\ lap..            0
2........................  Mod. decel to 35 MPH............           -5
2........................  Mod accel to 45 MPH.............            3
2........................  Cruise at 45 MPH for \1/4>\ lap.            0
2........................  Mod. decel to stop..............           -5
--------------------------
3........................  Idle 10 sec.....................            0
3........................  Hard accel to 55 MPH............            4
3........................  Cruise at 55 MPH for \1/4\ lap..            0
3........................  Mod. decel to 45 MPH............           -5
3........................  Mod accel to 55 MPH.............            2
3........................  Cruise at 55 MPH for \1/4\ lap..            0
3........................  Mod. decel to 45 MPH............           -5
3........................  Mod accel to 60 MPH.............            2
3........................  Cruise at 60 MPH for \1/4\ lap..            0
3........................  Mod. decel to 50 MPH............           -5
3........................  Mod. accel to 60 MPH............            2
3........................  Cruise at 60 MPH for \1/4\ lap..            0
3........................  Mod. decel to stop..............           -4
--------------------------
4........................  Idle 10 sec.....................            0
4........................  Hard accel to 80 MPH............            3
4........................  Coastdown to 70 MPH.............           -1
4........................  Cruise at 70 MPH for \1/2\ Lap..            0
4........................  Mod. decel to 50 MPH............           -3

[[Page 2838]]

 
4........................  Mod accel to 65 MPH.............            2
4........................  Cruise at 65 MPH for \1/2\ lap..            0
4........................  Mod. decel to 50 MPH............           -3
--------------------------
5........................  Mod accel to 75 MPH.............            1
5........................  Cruise at 75 MPH for \1/2\ lap..            0
5........................  Mod. decel to 50 MPH............           -3
5........................  Lt. accel to 70 MPH.............            1
5........................  Cruise at 70 MPH for \1/2\ lap..            0
5........................  Mod. decel 50 MPH...............           -3
--------------------------
6........................  Mod accel to 70 MPH.............            2
6........................  Coastdown to 60 MPH.............           -1
6........................  Cruise at 60 MPH for \1/2\ lap..            0
6........................  Mod. decel to 50 MPH............           -4
6........................  Mod. accel to 65 MPH............            1
6........................  Cruise at 65 MPH for \1/2\ lap..            0
6........................  Mod. decel to stop..............           -4
--------------------------
7........................  Idle 45 sec.....................            0
7........................  Hard accel to 55 MPH............            4
7........................  Cruise at 55 MPH for \1/4\ lap..            0
7........................  Mod. decel to 40 MPH............           -5
7........................  Mod. accel to 55 MPH............            2
7........................  Cruise at 55 MPH for \1/4\ lap..            0
7........................  Mod. decel to 40 MPH............           -5
7........................  Mod. accel to 50 MPH............            2
7........................  Cruise at 50 MPH for \1/4\ lap..            0
7........................  Mod. decel to 40 MPH............           -5
7........................  Mod. accel to 50 MPH............            2
7........................  Cruise at 50 MPH for \1/4\ lap..            0
7........................  Mod. decel to stop..............           -5
------------------------------------------------------------------------

    The standard road cycle is represented graphically in the following 
figure:

[[Page 2839]]

[GRAPHIC] [TIFF OMITTED] TR17JA06.066

* * * * *

Appendix VII to Part 86--Standard Bench Cycle (SBC)

    1. The standard bench aging durability procedures [Ref. Sec.  
86.1823-08(d)] consist of aging a catalyst-oxygen-sensor system on 
an aging bench which follows the standard bench cycle (SBC) 
described in this appendix.
    2. The SBC requires use of an aging bench with an engine as the 
source of feed gas for the catalyst.
    3. The SBC is a 60-second cycle which is repeated as necessary 
on the aging bench to conduct aging for the required period of time. 
The SBC is defined based on the catalyst temperature, engine air/
fuel (A/F) ratio, and the amount of secondary air injection which is 
added in front of the first catalyst.

Catalyst Temperature Control

    1. Catalyst temperature shall be measured in the catalyst bed at 
the location where the highest temperature occurs in the hottest 
catalyst. Alternatively, the feed gas temperature may be measured 
and converted to catalyst bed temperature using a linear transform 
calculated from correlation data collected on the catalyst design 
and aging bench to be used in the aging process.
    2. Control the catalyst temperature at stoichiometric operation 
(01 to 40 seconds on the cycle) to a minimum of 800 [deg]C ( 10 [deg]C) by selecting the appropriate Engine speed, load, 
and spark timing for the engine. Control the maximum catalyst 
temperature that occurs during the cycle to 890 [deg]C ( 
10 [deg]C) by selecting the appropriate A/F ratio of the engine 
during the ``rich'' phase described in the table below.
    3. If a low control temperature other than 800 [deg]C is 
utilized, the high control temperature shall be 90 [deg]C higher 
than the low control temperature.

                                           Standard Bench Cycle (SBC)
----------------------------------------------------------------------------------------------------------------
                                                                                                   Secondary air
           Time  (seconds)                               Engine air/fuel ratio                       injection
----------------------------------------------------------------------------------------------------------------
01-40................................  14.7 (stoichiometric, with load, spark timing, and engine            None
                                        speed controlled to achieve a minimum catalyst
                                        temperature of 800 [deg]C).
41-45................................  ``Rich'' (A/F ratio selected to achieve a maximum                    None
                                        catalyst temperature over the entire cycle of 890
                                        [deg]C, or 90[deg] higher than low control temperature).
46-55................................  ``Rich'' (A/F ratio selected to achieve a maximum              3% ( 0.1%)
                                        [deg]C, or 90[deg] higher than low control temperature).
56--60...............................  14.7 (stoichiometric, same load, spark timing, and engine      3% ( 0.1%)
----------------------------------------------------------------------------------------------------------------


[[Page 2840]]

[GRAPHIC] [TIFF OMITTED] TR17JA06.067

Appendix VIII to Part 86--Aging Bench Equipment and Procedures

    This appendix provides specifications for standard aging bench 
equipment and aging procedures which may be used to conduct bench 
aging durability under the provisions of Sec.  86.1823-08.

1. Aging Bench Configuration

    The aging bench must provide the appropriate exhaust flow rate, 
temperature, air-fuel ratio, exhaust constituents and secondary air 
injection at the inlet face of the catalyst.
    a. The EPA standard aging bench consists of an engine, engine 
controller, and engine dynamometer. Other configurations may be 
acceptable (e.g. whole vehicle on a dynamometer, or a burner that 
provides the correct exhaust conditions), as long as the catalyst 
inlet conditions and control features specified in this appendix are 
met.
    b. A single aging bench may have the exhaust flow split into 
several streams providing that each exhaust stream meets the 
requirements of this appendix. If the bench has more than one 
exhaust stream, multiple catalyst systems may be aged 
simultaneously.

2. Fuel and Oil

    The fuel used by the engine shall comply with the mileage 
accumulation fuel provisions of Sec.  86.113 for the applicable fuel 
type (e.g., gasoline or diesel fuel). The oil used in the engine 
shall be representative of commercial oils and selected using good 
engineering judgement.

3. Exhaust System Installation

    a. The entire catalyst(s)-plus-oxygen-sensor(s) system, together 
with all exhaust piping which connects these components, [the 
``catalyst system''] will be installed on the bench. For engines 
with multiple exhaust streams (such as some V6 and V8 engines), each 
bank of the exhaust system will be installed separately on the 
bench.
    b. For exhaust systems that contain multiple in-line catalysts, 
the entire catalyst system including all catalysts, all oxygen 
sensors and the associated exhaust piping will be installed as a 
unit for aging. Alternatively, each individual catalyst may be 
separately aged for the appropriate period of time.

4. Temperature Measurement

    Catalyst temperature shall be measured using a thermocouple 
placed in the catalyst bed at the location where the highest 
temperature occurs in the hottest catalyst (typically this occurs 
approximately one-inch behind the front face of the first catalyst 
at its longitudinal axis). Alternatively, the feed gas temperature 
just before the catalyst inlet face may be measured and converted to 
catalyst bed temperature using a linear transform calculated from 
correlation data collected on the catalyst design and aging bench to 
be used in the aging process. The catalyst temperature must be 
stored digitally at the speed of 1 hertz (one measurement per 
second).

5. Air/Fuel Measurement

    Provisions must be made for the measurement of the air/fuel (A/
F) ratio (such as a wide-range oxygen sensor) as close as possible 
to the catalyst inlet and outlet flanges. The information from these 
sensors must be stored digitally at the speed of 1 hertz (one 
measurement per second).

6. Exhaust Flow Balance

    Provisions must be made to assure that the proper amount of 
exhaust (measured in grams/second at stoichiometry, with a tolerance 
of 5 grams/second) flows through each catalyst system 
that is being aged on the bench. The proper flow rate is determined 
based upon the exhaust flow that would occur in the original 
vehicle's engine at the steady state engine speed and load selected 
for the bench aging in paragraph (7).

7. Setup

    a. The engine speed, load, and spark timing are selected to 
achieve a catalyst bed temperature of 800 [deg]C ( 10 
[deg]C) at steady-state stoichiometric operation.
    b. The air injection system is set to provide the necessary air 
flow to produce 3.0% oxygen ( 0.1%) in the steady-state 
stoichiometric exhaust stream just in front of the first catalyst. A 
typical reading at the upstream A/F measurement point (required in 
paragraph 5) is lambda 1.16 (which is approximately 3% oxygen).
    c. With the air injection on, set the ``Rich'' A/F ratio to 
produce a catalyst bed temperature of 890 [deg]C ( 10 
[deg]C). A typical A/F value for this step is lambda 0.94 
(approximately 2% CO).

8. Aging Cycle

    The standard bench aging procedures use the standard bench cycle 
(SBC) which is described in Appendix VII to Part 86. The SBC is 
repeated until the amount of aging calculated from the bench aging 
time (BAT) equation [ref. Sec.  86.1823-08 (d)(3)] is achieved.

9. Quality Assurance

    a. The temperatures and A/F ratio information that is required 
to be measured in paragraphs (4) and (5) shall be reviewed 
periodically (at least every 50 hours) during aging. Necessary 
adjustments shall be made to assure that the SBC is being 
appropriately followed throughout the aging process.
    b. After the aging has been completed, the catalyst time-at-
temperature collected during the aging process shall be tabulated 
into a histogram with temperature bins of no larger than 10 [deg]C. 
The BAT equation and the calculated effective reference temperature 
for the aging cycle [ref. Sec.  86.1823-08(d)] will be used to 
determine if the appropriate amount of thermal aging of the catalyst 
has in fact occurred. Bench aging will be extended if the thermal 
effect of the calculated aging time is not at least 95% of the 
target thermal aging.

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10. Startup and Shutdown

    Care should be taken to assure that the maximum catalyst 
temperature for rapid deterioration (e.g., 1050 [deg]C) does not 
occur during startup or shutdown. Special low temperature startup 
and shutdown procedures may be used to alleviate this concern.

Appendix IX to Part 86--Experimentally Determining the R-Factor for 
Bench Aging Durability Procedures

    The R-Factor is the catalyst thermal reactivity coefficient used 
in the bench aging time (BAT) equation [Ref. Sec.  86.1826-
08(d)(3)]. Manufacturers may determine the value of R experimentally 
using the following procedures.
    1. Using the applicable bench cycle and aging bench hardware, 
age several catalysts (minimum of 3 of the same catalyst design) at 
different control temperatures between the normal operating 
temperature and the damage limit temperature. Measure emissions (or 
catalyst inefficiency (1-catalyst efficiency)) for each constituent. 
Assure that the final testing yields data between one- and two-times 
the standard.
    2. Estimate the value of R and calculate the effective reference 
temperature (Tr) for the bench aging cycle for each 
control temperature according to the procedure described in Sec.  
86.1826-08(d)(4).
    3. Plot emissions (or catalyst inefficiency) versus aging time 
for each catalyst. Calculate the least-squared best-fit line through 
the data. For the data set to be useful for this purpose the data 
should have an approximately common intercept between 0 and 4000 
miles. See the following graph for an example.
    4. Calculate the slope of the best-fit line for each aging 
temperature.
    5. Plot the natural log (ln) of the slope of each best-fit line 
(determined in step 4) along the vertical axis, versus the inverse 
of aging temperature (1/(aging temperature, deg K)) along the 
horizontal axis, Calculate the least-squared best-fit lines through 
the data. The slope of the line is the R-factor. See the following 
graph for an example.
[GRAPHIC] [TIFF OMITTED] TR17JA06.068

    6. Compare the R-factor to the initial value that was used in 
Step 2. If the calculated R-factor differs from the initial value by 
more than 5%, choose a new R-factor that is between the initial and 
calculated values, then repeat Steps 2-6 to derive a new R-factor. 
Repeat this process until the calculated R-factor is within 5% of 
the initially assumed R-factor.
    7. Compare the R-factor determined separately for each 
constituent. Use the lowest R-factor (worst case) for the BAT 
equation.


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[GRAPHIC] [TIFF OMITTED] TR17JA06.069

[FR Doc. 06-74 Filed 1-13-06; 8:45 am]
BILLING CODE 6560-50-P