[Federal Register Volume 69, Number 64 (Friday, April 2, 2004)]
[Proposed Rules]
[Pages 17532-17568]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-6297]



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Part III





Environmental Protection Agency





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40 CFR Part 86



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

  Federal Register / Vol. 69, No. 64 / Friday, April 2, 2004 / Proposed 
Rules  

[[Page 17532]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 86

[FRL-7638-8]
RIN 2060-AK76


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

AGENCY: Environmental Protection Agency.

ACTION: Notice of proposed rulemaking.

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SUMMARY: This proposed 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 proposes 
procedures to be used by manufacturers to demonstrate the expected rate 
of deterioration of the emission levels of their vehicles.

DATES: Written comments on this NPRM must be submitted on or before May 
17, 2004. A public hearing will be held on April 19, 2004. Requests to 
present oral testimony must be received on or before April 12, 2004. If 
EPA receives no requests to present oral testimony by this date, the 
hearing will be canceled.

ADDRESSES: Comments: Comments may be submitted by mail to: Air Docket, 
Environmental Protection Agency, Mailcode: 6102T, 1200 Pennsylvania 
Ave., NW., Washington, DC 20460, Attention Docket ID No. OAR-2002-0079. 
Comments may also be submitted electronically, by facsimile, or through 
hand delivery/courier. For more information submitting comments and on 
the comment procedure and public hearings, follow the detailed 
instructions as provided in Section V, ``Public Participation'' 
section. We must receive them by the date indicated under DATES above. 
Paper copies of written comments (in duplicate if possible) should also 
be sent to the general contact person listed below.

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: Eldert Bontekoe, Vehicle Programs and Compliance 
Division, U.S. EPA, 2000 Traverwood, Ann Arbor, Michigan 48105, 
telephone: (734) 214-4442, 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
II. How did EPA develop the proposed durability procedures?
    A. What is the purpose of the durability program?
    B. What are the factors that affect exhaust emission 
deterioration?
    C. The strawman durability procedures
    1. The whole-vehicle aging procedures
    2. The bench aging procedures
    3. Allowable customization of the bench aging procedures
    D. Development of today's proposal from the strawman durability 
procedures
    1. The durability objective
    2. Cycle severity for the SRC (Comments 1 and 2)
    3. Alternative and customized cycles (Comment 3)
    4. The standard bench cycle (Comment 4)
    5. Bench aging time (Comment 5)
    6. Bench aging specifications (Comment 6)
    7. Adjusting durability procedures based on IUVP data (Comments 
7 and 8)
    8. Reproducibility by outside parties (Comment 9)
    9. Confidentiality of emissions test results submitted under the 
durability program
    E. Diesel Vehicle Exhaust Deterioration
    F. Evaporative and refueling durability procedures
III. What is EPA proposing 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
    1. Effective Date
    2. Carrying-over 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 proposal
    B. Environmental impacts
V. What are the opportunities for public participation?
    A. Copies of This Proposal and Other Related Information
    B. Submitting Comments on This Proposal
    C. Areas where EPA specifically requests public comment
    D. Public hearing
VI. What are the Statutory and Executive Order Reviews for this 
Proposed 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

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, 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

[[Page 17533]]

certification regulations are known as ``CAP 2000'' (Compliance 
Assurance Program).\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 proposal will apply to those 
subsets of 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 the 
proposed 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 action specifies the methods that 
manufacturers must use to determine emissions deterioration for the 
purpose of certification. EPA is not proposing to change the existing 
regulations for determining emissions-related component durability.
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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 the 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 proposal 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 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

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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 criteria 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 18, 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 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 
dynamometer, a ``slave'' engine, and required controllers and 
sensors to achieve the desired operation of the engine on the 
dynamometer.
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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 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

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reconsider the CAP 2000 regulations. EPA requested public comment on 
the petition, 64 FR 60,401 (November 5, 1999 and 64 FR 70,665 (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 45,777 (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 45,777 (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 (D.C. 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.]
    The Court's decision stated that ``CAP 2000, rather than 
constituting an EPA establishment `by regulation' of `methods and 
procedures for making tests,' as required by section 206(d), is instead 
a promulgation of criteria for the later establishment of such methods 
and procedures by private negotiation between the EPA and each 
regulated auto maker. So it is `not in accordance with law.' '' The 
Court vacated ``the CAP 2000 program'' and remanded the case to the EPA 
with instructions to establish test methods and procedures by 
regulation. [Id.]
    Since the issue before the Court was the legality of EPA's adoption 
of the CAP 2000 durability provisions, 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 proposal 
is the result of the court's decision, and is limited to emission 
durability procedures.

II. How Did EPA Develop the Proposed Durability Procedures?

    The process and data used to develop the proposed durability 
procedures is discussed below. Additional data and analysis used by EPA 
in the regulation development process are contained in the Agency's 
Draft Technical Support Document (TSD).

A. What Is the Purpose of the Durability Program?

    EPA issues certificates of conformity based on testing and other 
information submitted by manufacturers which verifies compliance with 
the applicable emission standards over the vehicles' useful life. The 
durability program is the tool used to adjust low mileage test results 
from emission data vehicles (EDV's) to predict emission results at full 
useful life mileage.
    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 useful life. We believe that the durability 
process used to support an application for certification should cover a 
significant majority of in-use vehicles that will be covered by that 
certificate. In the CAP 2000 rulemaking, EPA established the 
requirement that manufacturers demonstrate the ``adequacy of [their] 
durability processes to effectively predict emission compliance for 
candidate in-use vehicles.\18\'' This objective remains in today's 
proposal.
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    \18\ Ref. 40 CFR 86.1823-01(b)(1). The term ``candidate in-use 
vehicles'' means vehicles which would meet the selection criteria of 
the in-use verification program (IUVP)).
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    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 
in-use vehicles. This was typically approximately 90 percent coverage 
of the distribution.\19\ In today's proposal we are taking the same 
approach, such that a durability program is expected to effectively 
predict a ``significant majority'', meaning coverage of approximately 
90 percent of the distribution of in-use emission levels and 
deterioration.
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    \19\ Ref. 63 FR 39660 (July 23, 1998).
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    In summary, the objective of the durability program is to 
effectively predict in-use emission deterioration rates and emission 
levels by covering the significant majority, meaning approximately 90 
percent, of the distribution of emission deterioration of candidate in-
use vehicles of each vehicle design which uses the durability program.
    A durability group \20\ can include several different vehicle 
designs which may have different emission levels and deterioration 
rates. In the CAP 2000 rulemaking, EPA required that the durability 
data vehicle (DDV) be the vehicle with the highest expected emission 
deterioration of the vehicles within the durability group [ref. 
86.1820-01]. (We are not proposing to change the DDV selection criteria 
in this rulemaking.)
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    \20\ A durability group is the basic classification unit of a 
manufacturer's product line as defined in Sec.  86.1822-01.
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    The durability program is used to calculate certification levels 
either by applying DFs to EDV low-mileage test data or by testing EDVs 
with aged emission control hardware installed. EPA issues a certificate 
when the certification levels of the EDV comply with the emission 
standards. Manufacturers normally design with an additional compliance 
margin between the standard and the certification level, to address 
various uncertainties. Especially for EDVs with certification levels at 
or just under the standards, we believe it is important to have some 
level of assurance that those levels are indeed predicting the full 
useful life emission levels of the significant

[[Page 17536]]

majority of in-use vehicles covered by the certificate.

B. What Are the Factors That Affect Exhaust Emission Deterioration?

    The first step in developing an exhaust durability program is 
identifying the significant sources of emission deterioration. Emission 
levels will increase over mileage if either (1) the engine-out 
emissions \21\ of the engine increase or (2) the effectiveness of the 
exhaust after-treatment devices decreases.
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    \21\ Engine-out emissions are the engine's emissions before they 
are treated by the catalytic converter or other after-treatment 
emission control devices.
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    For all current-design light- and heavy-duty vehicles (excluding 
diesel-fueled vehicles) the catalytic converter is the only exhaust 
after-treatment device in use.\22\ EPA presented evidence in its draft 
technical support document for the CAP 2000 proposal \23\ that engine-
out emissions exhibit no significant deterioration for these current 
technology vehicles. This conclusion is also supported by an Society of 
Automotive Engineers (SAE) paper.\24\ Consequently, the Agency believes 
that engine-out emission increase is not a significant source of 
emission deterioration. Whatever minor level of deterioration may occur 
as a result of engine-out emission increases, it can be represented by 
an additional amount of catalyst aging.
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    \22\ Issues related to emissions deterioration for diesel-fueled 
vehicles are discussed in section II E.
    \23\ The technical support document for CAP 2000 proposal can be 
viewed in docket number A-96-50. The data that supports stable 
engine-out emissions is contained in Appendix I of that document.
    \24\ Reference: ``In-Use Emissions with Today's Closed-Loop 
Systems'' by H. Haskew and T. Liberty of General Motors, SAE No. 
910339.
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    The major source of emission deterioration in current technology 
vehicles today is the loss of catalyst efficiency. The two major 
sources of this efficiency loss are accumulated thermal exposure and 
poisoning. Minor sources of deterioration include coating of the 
catalyst substrate with fuel impurities, and physical deterioration of 
the catalysts such as the loss of catalytic material. Loss of effective 
fuel control due to deterioration of the oxygen sensor can also lead to 
lower catalyst efficiency as the vehicle ages and, therefore, to 
increased emission deterioration.
    The sources of catalyst poisoning are compounds contained in the 
fuel and in the lubricating oil (chiefly lead (Pb), phosphorus (P), and 
sulfur (S)). EPA has made significant strides to reduce poisons in 
fuels by fuel regulation, including regulations that have eliminated 
lead and significantly reduced sulfur levels in automobile fuels. The 
Alliance of Automobile Manufacturers (the ``Alliance'') has conducted 
periodic surveys of fuel used across the United States which have 
documented the extent of these reductions. Manufacturers generally use 
representative commercially-available fuel for testing and mileage 
accumulation on durability data vehicles. They are required to do so 
\25\ for mileage accumulation on EDVs. Lubrication oils have also 
improved over the years. While EPA does not regulate the oils, the 
American Petroleum Institute (API) together with the International 
Lubrication and Standardization and Approval Committee (ILSAC) have 
developed voluntary oil certification levels and evaluation procedures. 
Only oils with the best certification levels are allowed to use the API 
``star-burst'' certification mark in packaging and advertisement. Over 
the years, API and ILSAC have established lower levels of phosphorous 
with new levels of oil certification. Today the most advanced oils are 
designated as GF3. Market forces have proven sufficient to encourage 
manufacturers to market oils that meet the latest API/ILSAC 
requirements. Today, almost all of oil used in automobile applications 
meet the GF3 oil specifications. The advances in oil and fuel 
formulation have reduced poisoning of the catalyst but have not 
eliminated it.
---------------------------------------------------------------------------

    \25\ Reference: 40 CFR 86.113-04(a)(3) or 40 CFR 86.113-
94(a)(2).
---------------------------------------------------------------------------

    Exposure to high temperatures leads to three major deterioration 
mechanisms in catalysts. First, high temperatures cause the coalescence 
of active material, called sintering. Sintering reduces the surface 
area available to perform catalytic reactions. This then reduces the 
effectiveness of the catalyst. Second, loss of wash-coat surface area 
is also accelerated at high temperatures. The loss of wash-coat surface 
area is an indirect cause of active material sintering. Finally, high 
temperatures can promote chemical reaction of one type of active 
material with another type of active material (such as the formation of 
Pt Pd alloy) and with other compounds in the catalyst (such as the 
formation of Pt Ni alloy). In their new chemical state the active 
material is less effective at reducing emissions. It has been widely 
reported in the technical literature that the effects of high catalyst 
temperature are cumulative and generally increase exponentially with 
increased temperature.\26\
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    \26\ References: ``Thermal Effect on Three-Way Catalyst 
Deactivation and Improvement'' by K. Ihara, K. Ohkubo, and Y. Niura 
of Mazda, SAE No. 871192 and ``High Temperature Deactivation of 
Three-Way Catalyst'' by L. Carol, N. Newman, and G. Mann of General 
Motors, SAE No. 892040.
---------------------------------------------------------------------------

    It is also reported in the technical literature that the air/fuel 
(A/F) ratio in the catalyst can affect the rate of thermal 
deterioration.\27\ The same temperature exposure experienced during 
lean catalyst A/F ratio causes significantly more deterioration than at 
rich or stoichiometric operation.
---------------------------------------------------------------------------

    \27\ References: ``Effect of High Temperatures on Three-Way 
Automobile Catalysts'' by R. H. Hammerle and C. H. Wu of Ford, SAE 
No. 840549; ``Thermal Effect on Three-Way Catalyst Deactivation and 
Improvement'' by K. Ihara, K. Ohkubo, and Y. Niura of Mazda, SAE No. 
871192, and ``Thermal Deterioration Mechanism of Pt/Rh Three-Way 
Catalysts'' by S. Matsunaga, K. Yokota, D. Hyodo, T.Suzuki, and H. 
Sobukawa of Toyota, SAE No. 982706.
---------------------------------------------------------------------------

    Three-way catalysts are only simultaneously effective at oxidizing 
hydrocarbons (HC) and carbon monoxide (CO) and reducing oxides of 
nitrogen (NOX) in a very narrow window of catalyst A/F ratio 
near stoichiometry.\28\ To maintain the A/F ratio control needed to 
assure high catalyst efficiency, all modern gasoline vehicles use feed-
back fuel control. The feed-back control system uses an oxygen sensor 
located just in front of the first catalyst to monitor whether the 
instantaneous A/F ratio is rich or lean and a computer engine 
controller to adjust the fuel system (in the opposite direction) to 
move towards stoichiometry. Although the A/F ratio may be sightly rich 
or lean at any given second, on a time-averaged basis the feed-back 
fuel system is able to control the fuel to very near stoichiometric 
levels. The oxygen sensor is the critical part of this system and is 
subject to the same sources of deterioration as the catalyst--thermal 
exposure, poisoning, physical deterioration, and coating.
---------------------------------------------------------------------------

    \28\ Reference: ``Operational Criteria Affecting the design of 
Thermally Stable Single-Bed Three-Way Catalysts'' by B. Cooper and 
T. Truex of Johnson Matthey, SAE No. 850128.
---------------------------------------------------------------------------

    Physical deterioration of the catalyst or oxygen sensor such as 
cracking or loss of the catalyst substrate, are rare events that 
typically occur because of a faulty design. These concerns are 
addressed by the component durability feature of the durability 
program. Under the component durability provisions, manufacturers are 
responsible to demonstrate using good engineering judgement that all 
emission related components are durable in the operating environment 
they will experience throughout the vehicle's useful life.

[[Page 17537]]

    Coating of the catalyst substrate or the oxygen sensor generally 
occurs due to contaminants in the fuel. These contaminants are not part 
of the fuel formulation, but occur by accident due to mishandling of 
fuel in the distribution process. Coating caused by contaminants in the 
fuel is beyond the scope of the durability program. On-the-other hand, 
coating of the oxygen sensor may also occur due to installation of the 
oxygen sensor with an improper anti-seize compound that contains 
material that coats the oxygen sensor in actual use. Coating of the 
oxygen senor in this case should be addressed during the component 
durability portion of the durability process.

C. The Strawman Durability Procedures

    In preparing this proposal, EPA initially developed ``strawman'' 
durability procedures. The strawman durability procedures contained 
both whole-vehicle and bench aging procedures. A copy of the strawman 
durability procedure is contained in the TSD. The following discussion 
summarizes the strawman durability procedures and the development 
rationale for those procedures.
    The strawman proposal was used to solicit feedback from key 
stakeholders. Today's proposal is based on the strawman durability 
procedures with adjustment reflecting our response to the comments we 
received from vehicle manufacturers, emission control equipment 
manufacturers, and Ethyl Corporation.
1. The Whole-Vehicle Aging Procedure
    Sources of emission deterioration on a road cycle.
    Whole-vehicle aging consists of running the entire vehicle on a 
track or engine dynamometer. The vehicle is driven on a road cycle 
which usually consists of a speed-versus-time trace with specified 
acceleration rates, fuel properties, and vehicle load. Vehicles aged 
using whole-vehicle aging procedures experience: (1) Catalyst thermal 
deterioration due to the heat generated in the catalyst during vehicle 
operation, (2) poisoning of the catalyst due to the consumption of fuel 
and lubrication oil, (3) degradation of the accuracy of fuel control, 
and (4) engine-out emission deterioration. Of these four sources of 
deterioration, catalyst temperature exposure is the predominant source 
and the easiest to control. Consequently, once a road cycle has been 
established that has a reasonable amount of poisoning, fuel control 
deterioration (typically from the oxygen sensor), and engine-out 
emissions deterioration, catalyst temperature exposure can be used to 
adjust the severity of the driving cycle to meet the desired objective.
    Poisoning is basically a function of number of miles run and the 
type and amount of the fuel and lubricating oil which is consumed. 
Engine-out emission deterioration is largely a function of miles run, 
but as discussed previously, engine-out emission deterioration is 
thought to be near zero. If the road cycle incorporates the full number 
of useful life miles and the fuel and oil used are representative of 
in-use, poisoning and engine-out deterioration should be appropriately 
accounted for.
    As previously discussed, oxygen sensor deterioration is a function 
of thermal exposure, poisoning, physical deterioration and coating. As 
discussed above, coating and physical deterioration are rare and more 
properly addressed by the component durability provisions than the 
emission deterioration procedures that are the subject of this 
proposal. Poisoning is caused from ingested oil and compounds in the 
fuel burned in the engine, the same sources of poisons experienced by 
catalysts. Addressing the poisoning issues for catalysts will address 
the same poisoning concerns for oxygen sensors because the sensors are 
in the same exhaust stream as the catalyst and will experience the same 
poisons as the catalyst. The remaining source of deterioration of 
oxygen sensors is thermal exposure. Since oxygen sensors are installed 
near the catalyst in the exhaust stream they experience the same heat 
transfer effect from the hot exhaust stream as the catalyst. 
Consequently, appropriate control of catalyst temperature during the 
road cycle will lead to appropriate oxygen sensor deterioration.
    Higher catalyst temperatures occur at higher engine speed and 
engine load. Engine speed and load are higher when vehicle speed, 
acceleration rates, and vehicle loading are higher. Consequently the 
speed and acceleration distribution of a road cycle will determine the 
amount of catalyst temperature and oxygen sensor deterioration.
    Developing a standard road (SRC) cycle to achieve the durability 
objective.
    An appropriate road cycle is one that meets the severity objective 
for the mileage accumulation cycle. As discussed previously, the 
objective of EPA's proposed durability program is to effectively cover 
a significant majority (approximately 90 percent) of the distribution 
of in-use emission deterioration of candidate in-use vehicles across 
the entire fleet of vehicles covered by the durability program. In 
developing a standard road cycle applicable to all manufacturers, the 
objective encompasses the entire fleet of vehicles.
    Once the test vehicle is selected and the vehicle load and fuel 
specifications are fixed, the only variable remaining that can 
influence the severity of a road cycle is the speed-versus-time 
distribution of the cycle. Simply matching the speed and acceleration 
distribution of typical or average in-use driving is not appropriate, 
because our objective is ninety percent coverage of the in-use emission 
deterioration. Average in-use driving speeds and accelerations 
represent only fifty percent coverage. Matching the driving speed and 
acceleration of the ninetieth percentile driver would not automatically 
accomplish that objective by itself, because there are additional 
variables in actual driving that influence the work performed by the 
engine and, consequently, the rate of emission deterioration. In-use 
driving includes operating the vehicle on various road surfaces (such 
as gravel and rough roads), over various road grades (up or down 
hills), in various weather conditions (cold, hot, raining, snowing, and 
winds), and with various accessories in operation (such as air 
conditioning, defroster, and headlights). Directionally, all of these 
additional variables result in additional engine work, and consequently 
lead to higher catalyst temperatures and more emission deterioration 
than operating the vehicle at the same speed-versus-time trace on a 
smooth, level track or on a dynamometer.
    Strawman road cycle.
    EPA developed a strawman version of a standard road cycle based the 
data available at that time. EPA reviewed speeds and acceleration rates 
that are typically encountered in-use \29\ and extrapolated what speeds 
and acceleration might be typical for the ninetieth-percentile driver. 
As discussed previously, EPA believed that the appropriate speed and 
accelerations should be higher than the ninetieth-percentile driver due 
to additional variables seen in actual driving that affect 
deterioration. EPA also reviewed the speeds and acceleration rates used 
by manufacturers' road cycles previously approved by EPA under the CAP 
2000 regulations (or approved under the RDP process and subsequently 
grand-fathered into the

[[Page 17538]]

CAP 2000 program) \30\. To be approved under CAP 2000 or the RDP 
program, as applicable, the manufacturers provided information that EPA 
believed showed that these cycles covered the significant majority, 
approximately 90 percent, of the distribution of emission deterioration 
rates seen in-use on their vehicles. This would cover deterioration 
from in-use speeds, accelerations, other driving conditions, vehicle 
load, fuel, and the like. EPA developed speeds and acceleration rates 
for the strawman standard road cycle in the high range of severity 
compared to the manufacturer-specific cycles, because the standard EPA 
cycle was to cover the entire fleet of vehicles while the individual 
manufacturer's cycle was targeted to only cover the breadth of their 
specific product line. Consequently, the strawman standard road cycle 
was conservative and targeted at a higher degree of severity than most 
manufacturer cycles.
---------------------------------------------------------------------------

    \29\ Reference: ``Federal Test Procedure Review Project: 
Preliminary Technical Report'', EPA publication no. 420-R-33-007.
    \30\ Several approved manufacturer road cycles are discussed in 
the TSD.
---------------------------------------------------------------------------

    The road cycle developed for the strawman durability procedures is 
described in the technical support document for this rule.
    At the time the strawman road cycle was being developed EPA did not 
have any catalyst time-at-temperature data measured on this cycle. This 
data became available as part of the comments received on the 
durability strawman proposal. As we will discuss in section II.D., we 
ultimately revised the strawman road cycle to better achieve our 
durability target based on this catalyst time-at-temperature data. That 
revised cycle became the standard road cycle that we are proposing 
today.
    Early termination of mileage accumulation.
    One concern with performing mileage accumulation on a whole vehicle 
over its full useful life period is the amount of time it takes. In the 
strawman road cycle, running a vehicle for 100,000 miles was estimated 
to take about 103 days.\31\ For Tier 2 vehicles with full useful life 
periods of 120,000 or 150,000 miles the time would be even higher (120 
and 147 days, respectively).
---------------------------------------------------------------------------

    \31\ Assuming a 22 hour workday, it would take 89 days to drive 
the full useful life miles and 14 days to perform the needed 
emission tests, for a total of 103 days.
---------------------------------------------------------------------------

    The strawman whole-vehicle procedure contained a provision allowing 
manufacturers to terminate mileage accumulation early at a minimum of 
75% of full useful life, and to project the full useful life 
deterioration factors using the upper 80% statistical confidence limit. 
This provision is similar to one contained in the RPD I regulations 
with the added limitation of using the upper 80th% confidence limit. 
[Ref. Sec.  40 CFR 86.094-26(a)(4)(i)(B)] It allows manufacturers to 
reduce the time and money associated with full useful life mileage 
accumulation. At the same time, it protects the integrity of the 
deterioration factor by requiring that a higher than average (upper 80% 
statistical confidence limit \32\) DF be projected.
---------------------------------------------------------------------------

    \32\ The 80% statistical confidence limit means that 80% of the 
time the real deterioration rate would be lower than the 
extrapolated value.
---------------------------------------------------------------------------

    Customization of strawman road cycle.
    We did not include provisions allowing customization of the 
strawman road cycle, other than to allow for early termination, as 
discussed above. Before considering customization, EPA needed more 
information, including data, on whether or not the strawman road cycle 
would achieve the durability objective discussed in II B.1 below. In 
the strawman proposal, we requested manufacturers to provide catalyst 
time-at-temperature data on the road cycle and the manufacturer's 
approved CAP 2000 durability cycle. We did receive some comparative 
catalyst data and other comments on the strawman proposal, discussed 
below, which led us to conclude that it would be appropriate to propose 
approval criteria allowing customization of the standard road cycle or 
alternative road cycles.
2. The Bench Aging Procedures
    Background.
    Bench aging procedures generally involve removing critical emission 
components, such as the catalyst and oxygen sensor, from the DDV and 
aging those components in an accelerated manner on an aging bench. The 
aged components are then either reinstalled on the DDV and emission 
tests are conducted to calculate a DF, or the EDV is tested with aged 
components which are directly installed on the test vehicle. In the 
latter case, the results of EDV testing are used to represent the 
certification levels without the need to calculate a DF. The objective 
of the bench aging procedure is to produce the desired target level of 
deterioration in a much shorter period of time than running a vehicle 
on a road cycle. If the bench aging is properly conducted then it will 
yield equivalent results to whole-vehicle aging.
    Sources of emission deterioration on the aging bench.
    As previously discussed, catalyst thermal exposure is the 
predominant source of emission deterioration. Temperature exposure of 
the catalyst can be more conveniently controlled on an aging bench than 
other sources of deterioration. On the catalyst aging bench, other 
sources of deterioration can be accounted for by increasing the amount 
of thermal aging of the catalyst.
    Degradation of the fuel control systems is one additional source of 
deterioration. It can lead to reduced efficiency of the catalyst and, 
therefore, to increased emission deterioration. In the modern feed-back 
fuel system the oxygen sensor is the critical emission control 
component. The oxygen sensor deteriorates due to accumulated thermal 
exposure as well as other reasons. As with the catalyst, thermal aging 
of the oxygen sensor can be used to represent all the sources of 
deterioration of the oxygen sensor.
    Using the bench procedures to replicate the emission deterioration 
seen on the road cycle.
    In summary, a bench aging procedure can use thermal aging of the 
catalyst-plus-oxygen-sensor [the ``catalyst system''] as a surrogate 
for whole-vehicle aging. By selecting the proper temperatures, amount 
of aging time, and mix of A/F ratios, the bench aging procedure can be 
designed to match the rate of deterioration predicted by a whole-
vehicle aging cycle, and meet the in-use emission performance design 
objectives expected of the durability program.
    The effects of temperature exposure on the catalyst are cumulative 
and increase exponentially with the temperature. Consequently, it is 
possible to replace a long period of catalyst exposure at a certain 
temperature with a shorter period of time at a higher temperature. By 
applying this principle over the entire range of catalyst temperature 
exposure, it is possible to represent the entire lifetime of catalyst 
temperature exposure as a much shorter period of time at a single 
elevated reference temperature.
    Determining the aging time on the bench.
    In 1889, the Swedish scientist Svent Arrehenius developed a 
theoretical formula, which came to be known as the Arrehenius equation, 
which relates chemical reaction rates with temperature. The Arrehenius 
equation is widely cited in chemical technical literature and it is 
noted that ``most chemical reactions closely follow'' \33\ the 
equation. For our strawman procedure, we developed a version of the 
Arrehenius equation, called the Bench

[[Page 17539]]

Aging Time (BAT) equation. The BAT equation compares the deterioration 
rates that occur at two different temperatures. The BAT equation allows 
us to convert a given amount of aging time at one temperature to a 
lesser time at a higher temperature while maintaining the same degree 
of emission deterioration.
---------------------------------------------------------------------------

    \33\ Reference: General Chemistry, by D. Ebbing and M. Wrighton, 
published in 1990 by Houghton Mifflin Co., Boston.
---------------------------------------------------------------------------

    Since the implementation of the RDP I regulations, beginning in the 
1993 model year, EPA has been evaluating the applicability of the BAT 
equation to durability demonstrations and experimenting with different 
coefficients for the equation. EPA also has been approving 
manufacturer-designed durability procedures under the RDP I and CAP 
2000 procedures. As part of the approval process, EPA required catalyst 
temperature histograms \34\ of both the manufacturer's procedures and 
the 70-mph AMA.\35\ EPA used this data to compare the severity of the 
AMA and the manufacturer's cycles. In general, we found that the BAT 
equation predicted a similar ratio of severity (the manufacturer's 
cycle divided by the AMA) for different manufacturers. Also, EPA noted 
that some manufacturers were also basing their bench cycle aging time 
calculations on similar principles as the Arrehenius equation and that 
they had developed coefficients similar to the ones we were using with 
the BAT equation. The BAT equation that EPA developed for the strawman 
durability process is discussed in the Technical Support Document for 
this rule.
---------------------------------------------------------------------------

    \34\ Ref. Advisory Circular No. 17-F (November 16, 1982).
    \35\ The 70 mph AMA is the original AMA promulgated in Appendix 
IV to Part 86 in 1977. It has a high speed on lap 11 of 70 mph. By 
policy, EPA had allowed manufacturers to use lower speeds (as low as 
55 mph) on lap 11 of the AMA in response to the 55 mph National 
Speed Limit which was enacted after promulgation of the AMA cycle in 
the appendix.
---------------------------------------------------------------------------

    To use the BAT equation to select the bench aging time for a given 
temperature, it is necessary to start with a known distribution of 
time-at-temperatures for the catalyst. The strawman version of the 
standard road cycle was designed to replicate the appropriate level of 
aging and it specifically targeted catalyst temperature as a method to 
accomplish the aging. Consequently, the distribution of catalyst time 
at temperature data on the standard road cycle is an appropriate target 
for a standard bench aging procedure. Therefore, the strawman 
durability program used catalyst temperature histograms run on the 
standard road cycle on the DDV configuration as input to the BAT 
equation to determine the bench aging time and temperature.
    The BAT equation and the Arrehenius equation upon which it is based 
assume that deterioration is determined strictly based on time-at-
temperature. However, as discussed previously, the A/F ratio in the 
catalyst can significantly affect the rate of deterioration that occurs 
for the same temperature exposure. Catalyst deterioration is highest 
when the A/F ratio of the catalyst is lean.
    One approach to address the effect of A/F ratio on aging is to 
separate the aging time into the three A/F ratio regimes; rich, 
stoichiometry, and lean; and consider each sub-set separately. Another 
approach would be to control the proportion of rich/stoichmetric/lean 
operation during bench aging and use a composite value of the catalyst 
thermal reactivity coefficient \36\ (R-value) based on that 
distribution in the BAT equation. Since EPA developed the R-value using 
this composite approach, this is the option we chose for the strawman 
durability program.
---------------------------------------------------------------------------

    \36\ The catalyst thermal reactivity is the ``R-Factor'' in 
EPA's proposed BAT equation to calculate the bench aging time. It is 
a measure, determined experimentally, of how sensitive the catalyst 
is to high temperature exposure. The BAT equation is discussed in 
more detail in section III of the preamble.
---------------------------------------------------------------------------

    Another variable that effects deterioration is poisoning. Little 
poisoning occurs on the bench cycle because the duration of the test is 
short (typically 100 to 300 hours). Consequently, only a limited amount 
of fuel is used and little lubrication oil is consumed by the engine. 
Nevertheless, although the effect is small, it is important to specify 
the fuel used. The strawman procedure specified the fuel as normal 
mileage accumulation fuel, which is representative of commercially 
available fuel. The strawman procedures did not discuss specifications 
for the oil to be used on the bench engine. Today's proposal requires 
that the oil used in the bench engine is to be selected using good 
engineering judgement.
    Controlling the A/F ratio on the bench [the strawman bench cycle].
    For the BAT equation to work properly, it is necessary to have an 
appropriate and fixed mix of A/F ratios experienced in the catalyst. 
This pre-determined mix of A/F ratios in the catalyst on the aging 
bench is called the ``bench cycle''. The technical literature \37\ 
discusses one bench cycle, called RAT A, that has been used to age 
catalysts on an aging bench. This bench cycle is also used by several 
manufacturers in their own procedures to conduct bench aging.
---------------------------------------------------------------------------

    \37\ The RAT A cycle is referenced in ``Application of 
Accelerated Rapid Aging Test (RAT) schedules with Poisons'' by D. 
Ball, A Mohammed, and W. Schmidt of Delphi, SAE No. 972846; ``A 
Survey of Automotive Catalyst Technologies using Rapid Aging Test 
Schedules which Incorporate Engine Oil Derived Poisons'' by D. Ball, 
and C. Kirby of Delphi, SAE No. 973050; and ``The Effects of Oil 
Derived Poisons on Three-Way Catalyst Performance'' by D. Lafyatis, 
R. Petrow, and C. Bennet of Johnson Matthey, SAE No. 2002-01-1093.
---------------------------------------------------------------------------

    The proportion of rich/stoichiometric/lean A/F ratios on the RAT A 
cycle follows the general trend of A/F ratios seen in the catalyst in 
use.\38\ The RAT A cycle has mostly stoichiometric A/F ratios with a 
small amount of lean and an even smaller amount of rich operation. The 
bench cycle does not need to exactly replicate what happens in use, in 
fact the RAT A cycle does not replicate typical in-use A/F ratios. The 
BAT equation, with the proper coefficients, will adjust aging time on 
that bench cycle to assure that the correct amount of aging occurs. EPA 
developed the proposed BAT coefficients using catalyst time-at-
temperature data measured on the RAT A cycle. The purpose of the bench 
cycle is to establish a fixed cycle of A/F ratios on the bench to 
eliminate A/F ratio as an uncontrolled variable. By developing a fixed 
bench cycle, the reference temperature of the cycle and catalyst time-
at-temperature data are the remaining independent variables to 
determine aging time on the bench. The bench cycle established in the 
strawman durability program is a slightly modified version of this RAT 
A cycle where the time at rich and lean operation was rounded to an 
even number of seconds.
---------------------------------------------------------------------------

    \38\ The TSD presents a study of rich/stoichiometry/lean A/F 
percentages provided by a manufacturer on one of their vehicles.
---------------------------------------------------------------------------

    The strawman durability program bench cycle consists of a 60-second 
cycle which is defined as follows based on the A/F ratio of the engine 
(which is part of the aging bench) and the rate of secondary air 
injection (shop air which is added to the exhaust stream in front of 
the first catalyst):

01 to 40 secs:
    14.7 A/F, no secondary air injection
41 to 45 secs:
    13.0 A/F ratio, no secondary air injection
46 to 55 secs:
    13.0 A/F ratio, 4% secondary air injection
56 to 60 secs:
    14.7 A/F ratio, 4% secondary air injection

    Strawman bench aging procedures and equipment
    The BAT equation uses a specific reference temperature to perform 
the bench aging time calculation. Because

[[Page 17540]]

the catalyst temperature varies during the bench cycle, the strawman 
durability program included experimental procedures to determine the 
effective reference temperature for the bench cycle. The effective 
temperature was calculated using the BAT equation and catalyst 
temperature histogram data measured on the aging bench following the 
bench cycle. The BAT equation is used to calculate the effective 
reference temperature by trial-and-error changes to the reference 
temperature (Tr) until the calculated aging time equals the 
actual time represented in the catalyst temperature histogram.
    As previously discussed, the BAT equation is used to take the time-
at-temperature data measured during an approved road cycle and 
determine the amount of time to age a catalyst system following the 
bench cycle on the aging bench that is necessary to recreate the 
deterioration effect of the road cycle's catalyst temperature exposure. 
The effects of A/F ratio on the severity of temperature exposure are 
addressed by the bench cycle's use of an appropriate mix of A/F ratios 
on the bench.
    There are additional sources of deterioration that occur on the 
road cycle that are not directly replicated on the bench. Engine-out 
deterioration is one source, but as previously discussed, engine-out 
deterioration is near zero. Of more significance, a road cycle accounts 
for more poisoning than the bench aging cycle. To account for the 
additional poisoning seen on the road cycle, and any engine-out 
deterioration that may exist, the aging time on the bench is increased 
to replace these shortfalls with additional thermal aging. In the 
strawman durability bench procedures we addressed the potential 
shortfall by the use of an ``A-factor'' in the BAT equation. The A-
factor increases the amount of thermal aging to account for all sources 
of non-thermal deterioration. The strawman procedure specified an A-
factor of 1.1, which increases aging time by 10 percent. We believe 
that there is very little deterioration left unaccounted by the BAT 
equation, Consequently, we selected an A-factor value of 1.1 (a 10% 
adjustment).
    The strawman durability procedures contain a description of 
equipment for an aging bench. Briefly, this includes a slave engine 
mounted to an engine dynamometer with an engine controller and 
provisions for secondary air injection. This bench aging configuration 
has been used by several manufacturers to conduct bench aging. It was 
also the method of aging that was used with the RAT A bench aging cycle 
which serves as the basis of the bench aging cycle developed for the 
strawman.
    The strawman bench aging procedures are discussed in more detail in 
the TSD. Briefly, the bench aging procedures begin by measuring 
catalyst time-at-temperature data on the standard road cycle for at 
least 100 miles. The data collected on the road is proportionally 
increased to represent the full useful life of the vehicle. The time-
at-temperature data and the effective temperature of the bench cycle 
(determined experimentally using a procedure being proposed today) are 
entered into the BAT equation to calculate how long to age the catalyst 
system on the bench. The catalyst-plus-oxygen-sensor system is 
installed on the aging bench. An engine controller controls the A/F 
ratio, speed, and spark timing of the engine and adds secondary air in 
front of the first catalyst according to the bench cycle. The bench 
cycle is repeated as necessary to conduct aging for the amount of time 
calculated from the BAT equation. Using this method, the bench aging 
procedures can reproduce the emission deterioration seen on any road 
cycle.
3. Allowable Customization of the Bench Aging Procedures
    The strawman bench procedure allowed the following bench aging 
variables to be customized by individual manufacturers in order to 
better achieve the durability program objective.
    a. The control temperature of EPA's rapid aging bench cycle. The 
BAT equation can be used to determine the appropriate aging time for 
any reasonable temperature experienced on the bench cycle and still 
provide equivalent aging to the strawman bench aging procedure. 
Choosing a higher temperature will shorten the aging time, while a 
lower temperature will lengthen the time. Because the relationship 
between deterioration and aging temperature is exponential, a small 
change in temperature will lead to a dramatic change in aging time. For 
example, changing the effective bench temperature from 800 to 850[deg] 
C will cut the aging time by more than 50 percent. However, care needs 
to be taken so that the maximum temperature seen on the bench does not 
exceed the temperature limit that leads to catalyst damage, generally 
in the range of 1000 to 1050[deg] C. EPA selected 800[deg] C as 
approximately the lowest reasonable control temperature which results 
in a relatively short aging time for many applications and which should 
keep the catalyst below the damage limit. Manufacturers would be 
allowed to use 800[deg] C without prior approval. Selection of another 
value for the control temperature on the bench cycle would allow 
manufacturers to complete the aging in a shorter period of time, but 
would have no effect on the amount of deterioration produced by the 
bench aging when calculating aging time with the BAT equation.
    b. The R-factor. The R-factor represents the catalyst sensitivity 
to temperature exposure. The catalyst design will affect the R-factor. 
In Appendix IX to the proposed regulations, we discuss how an R-factor 
may be determined for a catalyst. The R-factors developed by EPA are 
based on experience with historical catalysts. An appropriately 
calculated R-factor (determined using the procedures of Appendix IX on 
the specific catalyst in question) will improve the accuracy of bench 
aging to meet the ninety percent deterioration objective.
    c. The A-factor. The A-factor represents how much extra catalyst 
thermal aging is necessary to reflect the additional catalyst 
deterioration experienced in use, from causes other than thermal 
exposure. Manufacturers can determine an appropriate A-factor based on 
IUVP or other in-use data. The use of a more appropriate A-factor will 
improve the accuracy of bench aging.
    d. Use fuel with additional poisons. Catalyst poisoning is a real-
world source of catalyst deterioration. The strawman bench aging 
procedures replace some the deterioration due to poisoning with 
additional thermal aging of the catalyst, reflected by the A-factor. 
Changing the bench aging to include more poisoning deactivation, e.g. 
by using fuel with lead, sulfur or phosphorus, would reduce the A 
factor.

D. Development of Today's Proposal From the Strawman Durability 
Procedures

    EPA provided the strawman durability procedures to many interested 
parties and received comments from a number of them. EPA also met 
individually with many automobile manufacturers and other parties. EPA 
refined and changed elements of the strawman durability procedures 
based on comments that we received from stakeholders on the strawman 
procedures and our improved understanding of how to accomplish our 
original objectives for the durability program. The principal comments 
\39\ that we received were:
---------------------------------------------------------------------------

    \39\ A full text of the comments (to the extent that they are 
releasable and not claimed as CBI) is contained in the TSD.
---------------------------------------------------------------------------

    (1) The strawman standard road cycle is too severe. It does not 
match in-use

[[Page 17541]]

distributions of speed and acceleration rates.
    (2) The road cycle does not have enough fuel cuts to match in-use 
driving experience.
    (3) Manufacturers should be allowed to use their own durability 
procedures.
    (4) The strawman bench aging cycle has a temperature spike 
occurring at a lean catalyst A/F ratio, which is not representative of 
in-use driving.
    (5) The BAT equation generates results that very nearly equal 
General Motors' own internal calculations.
    (6) The strawman bench aging cycle should have a defined high 
temperature value rather than defining the A/F ratio and secondary air 
injection rates
    (7) A defined approach of when and how to use IUVP data to adjust 
durability procedures is not appropriate.
    (8) If the IUVP data shows that a manufacturer meets emission 
standards in use (because, for example, the manufacturer certified with 
a sufficient compliance margin, known as ``headroom''), the Agency 
should not be concerned and should not make decisions based on the 
accuracy of the certification emission deterioration projection seen in 
isolation.
    (9) The public should be provided with sufficient information to 
duplicate the deterioration results of any manufacturer-specific 
procedures that are CBI.
    (10) The Agency should mandate the public release of all 
information provided by manufacturers (required or voluntarily 
submitted) to obtain approval for an alternative cycle.
1. The Durability Objective
    EPA continues to believe that the objective established for the 
strawman durability program is appropriate. It is the same objective 
that EPA had stated in the CAP 2000 rulemaking for durability 
procedures. EPA received no adverse comments on the durability 
objective when it was presented as part of the strawman durability 
discussion.
    EPA is proposing that the objective of the durability program is to 
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 of each vehicle design which uses the durability program. 
A significant majority means approximately 90% of the distribution.
2. Cycle Severity for the SRC (Comments 1 and 2)
    Several manufacturers commented that the strawman road cycle was 
too severe, i.e., that the strawman road cycle produced more emission 
deterioration than necessary to meet the durability objective of 90 
percent effective coverage. Several manufacturers supplied data that 
compared the thermal severity of their cycle, or a publically available 
cycle, to the strawman road cycle. The manufacturer cycles used in this 
comparison, with one exception, have been approved under the CAP 2000 
durability regulations. During that approval process, the manufacturers 
provided information \40\ that EPA believed showed that the cycles 
effectively covered approximately 90 percent of the in-use distribution 
of emission deterioration for their vehicles. The in-use data supplied 
by those manufacturers as part of the RDP I [IUVP in-use data is not 
yet available] process over several years have demonstrated good 
compliance with emission standards in use. For the durability programs 
used in the analysis discussed later in this section, all the in-use 
data demonstrated at least 90 percent compliance with the standards. 
Furthermore, the DFs used during certification were, for the most part, 
significantly larger than average deterioration represented by the in-
use data. We also evaluated several of these durability processes using 
the available RDP in-use emission data and, although the amount of data 
does not meet our minimum data requirement of 20 test vehicles, we have 
concluded that these processes appear to meet the approval criteria and 
durability objective being proposed today. Based on these screening 
criteria, we believe that these durability processes generally meet the 
durability objective which is being proposed today.\41\
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    \40\ In-use emissions information supplied by manufacturers is 
contained in the technical support document and docket to the CAP 
2000 rule.
    \41\ EPA has pursued remedies whenever a manufacturer's in-use 
data demonstrates that the objective of the durability process was 
not achieved in actual use.
---------------------------------------------------------------------------

    Therefore, we would expect that EPA's standard road cycle, if 
properly targeted to achieve the durability objective, should result in 
similar catalyst temperature exposure as the manufacturers cycles. The 
fact that the strawman road cycle proved more severe than the 
manufacturers' cycles indicated it was also more severe than necessary 
to meet EPA's durability objective.
    The relative severity data supplied \42\ in the manufacturers' 
comments showed that the strawman road cycle was about 50 percent more 
severe than the average manufacturer road cycle. That is, the amount of 
deterioration from the strawman road cycle was approximately 50 percent 
more than that of the average manufacturer's road cycle. The data 
ranged from approximately equal severity, to the strawman being about 
twice as severe as the manufacturer's cycle. The results depended on 
the type of vehicle that was used to make the comparison and the cycle 
to which it was compared.
---------------------------------------------------------------------------

    \42\ Refer to the TSD for a full presentation of the comparative 
severity between the strawman road cycle and various manufacturer 
cycles.
---------------------------------------------------------------------------

    This catalyst time-at-temperature data was not available when the 
strawman road cycle was being developed. Prior to the availability of 
this data our estimate of how closely the strawman road cycle achieved 
the durability objective was based mainly on driving characteristics 
and extrapolated expected effects on catalyst temperature. Based on 
this new data, EPA now believes that the strawman road cycle is too 
severe compared to the stated objective for the durability program. The 
Standard Road Cycle (SRC) that EPA is proposing today has been modified 
from the strawman version to reduce its severity and to more accurately 
achieve EPA's durability objective for the entire fleet of vehicles.
    Since the objective of the durability program is to effectively 
cover a significant majority of emission deterioration, we did not 
attempt to match average in-use speed or acceleration rate 
distributions. Matching average in-use driving experience on the SRC 
would lead to a cycle that only covered 50 percent of the distribution 
of in-use emission deterioration. Consequently, EPA rejected the 
suggestion that the SRC merely match the in-use distributions of speed 
and acceleration rates. The speeds and acceleration rates of the SRC 
are generally somewhat higher than average in-use data to fulfill our 
target of effectively covering 90 percent of the population's in-use 
emission levels.
    To develop the SRC that EPA is proposing, EPA reviewed those 
manufacturer cycles which used a speed-versus-time trace run for the 
vehicle's full useful life to see how they developed their road cycle 
to reach an appropriate target level of severity. We reviewed speed and 
acceleration rates

[[Page 17542]]

used on the Ford HSC and Toyota's U02 and 9-Lap cycles.\43\
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    \43\ Refer to the TSD for a description of Toyota's U02 and 9-
Lap cycles and Ford's HSC cycle. The GM road cycle was not included 
in the analysis because it does not involve mileage accumulation 
based on a speed-versus-time trace.
---------------------------------------------------------------------------

    Each of these cycles contained a high-speed driving mode which 
accounted for over one-third of the driving time; speeds in the high-
speed mode varied between 60 and 75 mph. The balance of the cycle time 
was spent in four lower speed laps which consisted of 30, 40, 50, and 
55 mph for the U02 and 9-Lap cycle and 35, 45, 55, and 45 mph [again] 
for the HSC cycle.
    EPA received catalyst temperature histogram data from General 
Motors (GM) which showed that the strawman road cycle produced three 
temperature peaks with little time at temperatures between these peaks. 
This contrasted with GM's own cycle which resulted in a more filled-out 
distribution resembling a typical skewed-normal distribution. GM 
commented that the strawman's unrealistic tri-modal temperature 
distribution was caused by the use of a few discrete-speed laps rather 
than a richer mixture of driving speeds and loads that occur in normal 
driving. EPA agrees with GM's observation that a more filled-out 
distribution of catalyst temperatures is a desirable outcome of a road 
cycle because it more closely matches a normal in-use distribution of 
catalyst temperatures.
    Toyota commented that the strawman does not contain enough fuel 
cuts.\44\ Toyota notes that fuel cuts lead to lean catalyst A/F ratios 
which in turn lead to more deterioration than the same temperature 
exposure at stoichiometric operation. EPA agrees with Toyota that a 
inclusion of a realistic number of fuel cuts in the SRC is desirable 
for the reasons discussed above.
---------------------------------------------------------------------------

    \44\ For most current technology vehicles the engine controller 
stops fueling the engine when the vehicle is stopping or 
experiencing a significant deceleration. These events are referred 
to as fuel cuts.
---------------------------------------------------------------------------

    Toyota recently re-designed their 9-Lap cycle to more closely match 
in-use levels of fuel-cuts. They call their new cycle the U02 cycle. To 
add more fuel cuts to their 9-Lap cycle, Toyota added three to five 
speed ``dips'' (of 5 to 15 mph) to each of the constant-speed laps in 
their cycle. The U02 also added an over-acceleration, coast-down event 
to each of their higher-speed modes, such as could occur when merging 
on to a limited-access highway. This event causes high temperature 
exposure to occur at a lean A/F in the catalyst.
    Ford suggested that EPA use a cycle they recently developed called 
MOD1. The MOD1 cycle was based on EPA's strawman road cycle but Ford 
reduced the maximum cruise speed to 80 mph and reduced the high-speed 
acceleration rates to 3 or 4 mph/second. Based on relative severity 
data supplied by Honda, the MOD1 cycle is about one-third less severe 
than the strawman cycle. The MOD1 cycle was slightly higher than midway 
in severity between the HSC and U02 cycles, less severe than Ford's HSC 
cycle, and more severe than Toyota's U02 cycle. Based on this data, the 
MOD1 cycle sits among the manufacturer's approved cycles which have 
been demonstrated to effectively meet the 90 percent durability target. 
Consequently, the MOD1 cycle seems to be a well-measured step in the 
right direction for overall severity. However, it did not address 
Toyota's comments that more fuel cuts were needed, nor GM's comments 
that a richer mix of speed distribution was desirable.
    Although there is a fair amount of variability in the 
manufacturers' relative severity data, about half of the severity data 
lie within a close band.\45\ That band of severity included the MOD1 
cycle. Consequently, because our target for the standard bench cycle is 
the same target (effective coverage of 90 percent) as the 
manufacturers' programs, it is appropriate to target near this 
consensus level of severity.
---------------------------------------------------------------------------

    \45\ The manufacturer supplied data showed a range of relative 
thermal severity (manufacturer/strawman) from 105% to 45%, 5 of the 
11 data points were in the range of 65% to 60%. The TSD contains the 
data and has an expanded discussion of our review of the data.
---------------------------------------------------------------------------

    EPA used all this information to develop the standard road cycle 
(SRC) proposed today. The SRC is targeted to effectively cover 90 
percent of the distribution of emission deterioration rates that occur 
on candidate vehicles in use, across the entire fleet. The speeds and 
acceleration rates on the SRC are reduced from the strawman proposal. 
The average speed has been lowered from 51.3 to 46.3 mph, the maximum 
cruise speed was lowered from 85 to 75 mph, and the acceleration rates 
for higher speed operation were lowered from 5 to 3 mph/second.
    The SRC also includes more fuel-cuts and a broader range of speed 
operation than seen on the strawman cycle to more closely match in-use 
experience. The number of fuel-cut events were increased from 14 to 24 
events during the seven laps (25.9 miles) of the cycle. The duration of 
each fuel-cut was also increased by employing slower rates of 
deceleration (deceleration rates varied between 5 and 8 mph/s in the 
strawman cycle and from 1 to 5 mph/s in the SRC). To expand the speed-
diversity of the road cycle, the number of different cruise speeds was 
increased from 6 speeds in the strawman cycle to 11 speeds in the SRC.
3. Alternative and Customized Cycles (Comment 3)
    Manufacturers suggested that they should be allowed to use their 
own durability procedures.
    Background.
    The CAP 2000 durability procedures required manufacturers to 
develop their own durability process subject to EPA approval. In the 
CAP 2000 rulemaking EPA established an objective for the durability 
process to ``predict the deterioration of a significant majority of in-
use vehicles.'' \46\ In addition to being effective at predicting 
emission deterioration rates and compliance of candidate in-use 
vehicles, these processes also reduced manufacturers' compliance costs 
by using methods that were already part of their development process.
---------------------------------------------------------------------------

    \46\ Ref. 63 FR 39661 (July 23, 1998).
---------------------------------------------------------------------------

    Although EPA is proposing standard whole-vehicle and bench-aging 
durability procedures, EPA is aware that the standard procedures may 
not achieve the durability objective, discussed in section II.D.1., for 
all manufacturers or for certain vehicle models. Because EPA's standard 
procedures are targeted to achieve the objective for the overall fleet 
of vehicles, they may over- or under-achieve the durability objective 
for some particular manufacturers or vehicles. For example, certain 
vehicles may have more available power than the vehicles EPA considered 
when designing the standard procedures. Such vehicles may be operated 
more aggressively in use than on the SRC. Similarly, vehicles which 
have less power may be operated less aggressively than on the SRC. When 
the standard procedures fail to achieve the durability objective, EPA 
believes that it is appropriate to allow an alternative process when it 
is necessary to achieve that objective.
    In addition, where the manufacturer durability procedure results in 
approximately equivalent levels of emission deterioration to those of 
the SRC being proposed today, the use of those procedures may represent 
a significant time and/or cost savings to the manufacturer because they 
may already be conducted as part of the manufacturer's development 
process. If a manufacturer can demonstrate that their alternative 
process is essentially equivalent to EPA's proposed standard road 
cycle, use of that process would have no effect on the emission

[[Page 17543]]

compliance determination made during certification.
    For these reasons, EPA is proposing that manufacturers may 
customize the standard EPA whole vehicle and certain aspects of bench 
aging durability processes. The proposed customization provisions 
include the ability to use either a ``customized SRC'' (the SRC cycle 
run for a different number of miles) or an alternative road cycle. EPA 
believes that these options will effectively address some 
manufacturers' desire to use the manufacturer-specific procedures in 
the future durability program.
    Customization of the SRC includes running the SRC for a shorter or 
longer period of time than specified and/or changing the fuel to 
include poisons such as lead or phosphorus combined with running the 
SRC for a shorter period of time. Alternatives to the SRC involve road 
cycles that employ time/speed traces different than the SRC.
    EPA is proposing approval criteria for these customized/alternative 
procedures. Any existing durability procedures approved under CAP 2000 
would have to be re-evaluated and approved under the requirements of 
the proposed regulations.
    Customized/Alternative Road Cycles.
    To obtain approval of a customized/alternative road cycle the 
manufacturer must demonstrate that the durability program will likely 
achieve the durability objective. As previously discussed, the proposed 
objective of the durability program is to 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 of 
each vehicle design which uses the durability program.
    To make the initial demonstration necessary for the Agency to 
approve a customized/alternative cycle, EPA is proposing 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.
    Because historical in-use data would be used to approve the 
manufacturer's durability process for current and future vehicles, it 
is necessary to limit that data to those that are applicable to the 
vehicle designs the manufacturer intends to cover with the durability 
process. Manufacturers must remove from the sample the following types 
of unrepresentative data: (1) Data which was collected on an engine/
emission control system which is not comparable to the current 
production designs, (2) data collected on a vehicle design which has 
been recalled due to a defective emission related part (unless the 
recall repair was performed on the test vehicle), or (3) data from 
vehicles that have been operated in an abnormal fashion that has 
impaired the effectiveness of the emission control system. In addition, 
manufacturers may also replace data from previously tested vehicles 
under the following conditions: (1) for in-use vehicles which have been 
primarily operated on high sulfur fuel (fuel with more than 80 ppm 
sulfur), if EPA has approved sulfur-removal preconditioning the 
manufacturer may replace the as-received testing with a second test 
conducted after sulfur-removal preconditioning has been performed, and 
(2) on a case-by-case basis, EPA may approve replacing the as-received 
testing performed on a vehicle which displays a MIL light that affects 
emission results with a second test performed after restorative 
maintenance has been performed. EPA would consider other exclusions or 
replacements of data on a case-by-case basis.
    The amount of in-use emission data required 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. EPA 
is reasonably confident that the SRC will achieve the durability 
objective for the general population of vehicles. Consequently, 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 encourages the manufacturer to 
submit more data than these minimum levels.
    The relative stringency of the customized/alternative cycle 
compared to the SRC must also be demonstrated. This could be 
accomplished by an evaluation of the two cycles using catalyst time-at-
temperature data from both cycles and using the BAT equation to 
calculate the required bench aging time of each cycle. For example, if 
the BAT equation calculates that 170 hours of aging on the SBC would be 
necessary to reproduce the thermal exposure of full useful life mileage 
on the SRC and 200 hours of aging to reproduce the thermal exposure on 
the customized SRC or alternative cycle, the manufacturer's cycle would 
be 85% as severe as the SRC (SRC/MFR x 100% = (170/200) x 100%= 85%). 
This value (85%) is the equivalency factor. The 85% equivalency factor 
means that running a vehicle on the SRC for 85% of the required mileage 
would result in the same emission deterioration as conducting full 
mileage on the alternative/customized cycle.
    If emissions data is available from the SRC, as well as catalyst 
time-at-temperature data, then that emissions information should be 
included in the evaluation of the relative stringency of the two cycles 
and the development of the equivalency factor. For example, if the 
manufacturer has calculated DFs using both cycles then these values may 
be compared directly. If the manufacturer cycle generates an additive 
DF for CO of 0.25 using the SRC and 0.20 using the manufacturer cycle, 
the manufacturers cycle would be 80% as severe as the SRC (Mfr/SRC x 
100% = (.20/.25) x 100% = 80%). The equivalency factor is the highest 
value calculated for the FTP emission constituents. In this example, 
assuming that the CO value is the highest of HC, CO, and NOX 
emission constituents, then the equivalency factor is 80%.
    This analysis would demonstrate the relative stringency between the 
customized SRC or alternative cycle and the SRC. It would also 
demonstrate the level of stringency of the SRC and the effectiveness of 
the SRC in meeting the durability objective. In many cases, especially 
before experience is gained in using the SRC to develop emissions data 
or certification levels, the same analysis will be used for 
demonstrating the relative stringency of the SRC noted above and 
developing the equivalency factor.
    In summary, approval of a customized/alternative road cycle 
requires an analysis of whether the

[[Page 17544]]

cycle will achieve the durability program objective using in-use 
emissions data and an evaluation of the relative stringency of the SRC 
and the manufacturer's program.
    Once the customized/alternative durability process is approved, EPA 
is proposing that for each test group the manufacturer must determine, 
using good engineering judgement, whether to apply the durability 
procedure to that particular test group. Manufacturers should only 
apply a durability process to a test group when they determine that the 
durability objective will be achieved for that test group in actual use 
on candidate in-use vehicles.
    Furthermore, EPA is proposing that the manufacturer may make 
modifications to an approved customized/alternative road cycle and 
apply them to a test group, to ensure that the modified cycle will 
effectively achieve the durability objective for future candidate in-
use vehicles. The manufacturer would be required to identify such 
modifications in its certification application and explain the basis 
for them. 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.
    EPA considered a more objective criteria for approval which would 
have required manufacturers to demonstrate that the customized/
alternative road cycle resulted in (1) a specified percent of the in-
use emission results that were less than or equal to the certification 
levels, and (2) at least 90 percent of the in-use emission data passing 
the applicable emission standards. However, EPA is not proposing such 
criteria because of concerns that the restrictions of such objective 
criteria are not needed to determine whether an alternative/customized 
cycle would meet the durability objective, and given the wide variety 
of circumstances and relevant data that might be employed in making a 
decision, it could lead to disapproval of a cycle that would achieve 
the durability objective.

Alternative Bench Procedures

    EPA believes that every bench aging procedure should be based upon 
measured vehicle performance on either the SRC or an EPA-approved road 
cycle. It is through the connection to the road cycle that EPA is 
assured that the alternative bench procedures will result in emission 
deterioration that achieves our durability objective. The BAT equation 
will calculate how much aging time is necessary on the bench to result 
in the same amount of emission deterioration experienced on the road 
cycle. As previously discussed, manufacturers must demonstrate that all 
customized/alternative road cycles meet the durability objective prior 
to Agency approval.
    EPA believes that customizing certain aspects of the standard bench 
aging procedure is appropriate if the modified procedure continues to 
produce the same amount of emission deterioration as the SRC or 
approved road cycle. Specifically, EPA believes that customization of 
the following aspects are appropriate for the reasons discussed below.
    a. Increasing the control temperature will reduce the time 
necessary to age the catalyst system on the bench, but it will not 
affect the severity of the aging because the BAT equation assures that 
the thermal aging seen on the road cycle is reproduced on the bench 
regardless of the effective temperature of the bench cycle.
    b. EPA believes that an experimentally-determined R-factor using 
the actual catalyst to be produced is expected to be more accurate than 
using the standard R-factor specified by EPA which was developed to 
apply to the industry as a whole. EPA is proposing a standard 
experimental procedure which manufacturers can use to develop a R-
factor that specifically applies their products. EPA believes that a R-
factor developed using this standard process will be more accurate than 
the standard R-factor because its development is based on data 
generated on the catalyst in question. The procedures for 
experimentally developing a R-factor are presented in Appendix IX of 
the proposed regulation.
    EPA will also consider the use of alternative methods to determine 
the R-factor. To have an alternative method approved by EPA, the 
manufacturer must demonstrate that the R-factor determined by this 
alternative process results in the same (or more) emission 
deterioration than the applicable approved road cycle.
    One method to make this demonstration is to determine FTP emission 
levels from a sufficient number of vehicles to meet the 80% statistical 
confidence criteria (discussed below) which have completed whole 
vehicle aging on the applicable road cycle. These vehicles must 
represent the breadth of the vehicles to be covered by this alternative 
method. These results are compared with results from the same (or a 
similar) vehicle which was tested with a catalyst system aged on the 
bench for the amount of time calculated from the BAT equation using the 
experimentally determined R-factor. To be approved, the emission 
results from the vehicle with the bench-aged catalyst system should be 
greater than or equal to the emission results for the vehicle aged on 
the road cycle with a minimum of 80% statistical confidence.
    c. The A-factor used in the BAT equation is designed to account for 
sources of deterioration other than thermal aging of the catalyst that 
occur in actual use but are not represented by the bench aging process. 
Determining the A-factor by actual in-use data is generally superior to 
the standard A-factor of 1.1.
    d. Conducting bench aging using fuel with additional poisons is 
worst case, consequently it is appropriate to do so without further 
evaluation by EPA. EPA expects when a manufacturer uses fuel with 
additional poisons during bench aging, they would also adjust the bench 
aging time by either calculating a new R-factor or a new A-factor. In 
that case, the approval procedures applicable to changing those factors 
would also apply.
    e. Generally, the SRC is used for generating the catalyst aging 
temperature histogram data used in the BAT. Using another road cycle is 
appropriate if the cycle has been approved as discussed above. The 
approval process assures that the alternative road cycle is expected to 
achieve the durability objective. Consequently, using an approved cycle 
to generate catalyst temperature histogram data is appropriate without 
further evaluation by EPA.
    f. EPA's standard bench cycle was developed to include an 
appropriate amount of rich, lean, and stoichiometric A/F operation on 
the bench for the typical vehicle. However, some vehicles have a fuel 
control strategy that controls fuel within a narrower band than 
typically occurs. In those cases, use of the SBC may over- or under-
predict actual emission deterioration in use. It is also possible that 
the SBC may result in a proper prediction of in-use emission 
deterioration, but a manufacturer may wish to use another bench cycle 
for reasons of cost and/or time savings, because that cycle is 
performed as part of the manufacturer's development process.
    If the manufacturer can demonstrate that bench aging following an 
alternative bench cycle results in the same (or more) emission 
deterioration than the SRC or an approved road cycle (whichever cycle 
is applicable), then the use of the alternative bench cycle will 
maintain or improve the ability to achieve the durability objective. In 
these cases, it is appropriate to allow the use

[[Page 17545]]

of a different bench cycle because the alternative bench cycle will 
accurately reproduce the emission deterioration seen on a road cycle 
which meets the durability objective. If a manufacturer uses a 
different bench cycle, they must also experimentally determine a R-
factor for the BAT equation. The manufacturer may use EPA's 
experimental process or another approved method to determine an R-
factor. [See paragraph b., above, for approval criteria to determine a 
customized R-factor]
    g. There may be some vehicles for which the BAT equation does not 
calculate appropriate aging times on the bench, although EPA is not 
aware of such vehicles at this time. In those cases, it would be 
appropriate to allow a manufacturer to use an alternative to the BAT 
equation provided it can demonstrate that bench aging time calculated 
by this alternative process results in the same (or more) emission 
deterioration than the road cycle upon which it is based.
    This demonstration can be made by determining FTP emission levels 
from a sufficient number of vehicles to meet the 80% statistical 
confidence criteria (discussed below) which have completed whole 
vehicle aging on the applicable road cycle. These vehicles must 
represent the breadth of the vehicles to be covered by the alternative 
cycle. The results are compared with results from the same (or a 
similar) vehicle which was tested with a catalyst system aged on the 
bench for the amount of time calculated from the alternative BAT 
equation. To be approved, the emission results from the vehicle with 
the bench-aged catalyst system should be greater than or equal to the 
emission results for the vehicle aged on the road cycle with a minimum 
of 80% statistical confidence.
4. The Standard Bench Cycle (Comment 4)
    The standard bench cycle (SBC) consists of a plot of catalyst 
temperature and A/F ratio versus time which is followed during bench 
aging. As discussed previously, the catalyst temperature and A/F ratio 
in the catalyst are the most important variables that affect the 
thermal aging rate of the catalyst. EPA is using its strawman bench 
aging cycle as the SBC in today's proposal. As discussed above, the SBC 
was developed based on methods reported in the literature which were 
also used effectively by automobile and catalyst manufacturers in the 
past.
    We received comments that the SBC may not represent the mixture of 
A/F ratios seen on certain vehicles during in-use operation. 
Furthermore, there was concern that lean catalyst A/F ratios occur 
during the higher catalyst temperatures experienced on the SBC. EPA 
agrees that the use of certain fuel control technologies, such as A/F 
ratio sensors rather than traditional oxygen sensors to control fuel 
metering and the use of algorithms to predict A/F ratio so that less 
switching between rich and lean A/F ratios is required for effective 
fuel control, could lead to less variation in A/F ratios in use. Such 
vehicles may see less time at lean A/F ratios in the catalyst. 
Consequently, those vehicles may be over-aged using the SBC. To address 
this concern, EPA is proposing to allow manufacturers to use a 
different bench cycle and/or bench aging time equation than the 
standard procedure, subject to EPA approval, as discussed above.
5. Bench Aging Time (Comment 5)
    EPA received a comment that the bench aging time (BAT) equation 
used in the strawman produced results nearly equal to those produced by 
General Motors' internal calculation. EPA also received confidential 
information from a manufacturer that the BAT equation resulted in 
nearly equal results as their confidential procedures. Based on this 
positive input, EPA has not changed the BAT equation for today's 
proposal from the equation used in the strawman durability procedures.
6. Bench Aging Specifications (Comment 6)
    In the strawman durability procedures, EPA defined the high 
temperature seen on the bench cycle indirectly by specifying the A/F 
ratio and the amount of secondary air injection. General Motors (GM) 
commented that it would be better to define high temperature directly 
because the high temperature has a significant impact on the aging that 
occurs on the aging bench. We agree that directly controlling the high 
temperature spike is a better procedure.
    Based on data from GM, the high temperature is usually about 
90[deg] C higher than the lower control temperature. We believe that 
there will be a similar temperature change on the SBC because it was 
developed from the RAT A cycle which GM used to generate this 
temperature data. Based on this data, EPA is proposing that the high 
temperature control point be 90[deg] C ( 10[deg] 
C) higher than the low temperature control point. In the SBC the lower 
control temperature is proposed to be 800[deg] C ( 10[deg] C) and the higher temperature to be 890[deg] C 
( 10[deg] C). The specification for the A/F ratio 
is now defined as ``rich'' with the exact A/F ratio to be selected to 
achieve the desired high temperature of 890[deg] C.
    We also changed the secondary air injection rate from 4% to 3% to 
match the RAT A cycle which was the basis of the strawman proposal. The 
higher rate of air injection prompted concerns about the ability to 
deliver that much air homogeneously across the exhaust flow. The 
original purpose of the secondary air injections was to assure a lean 
catalyst A/F ratio (how lean was not the issue) and to determine the 
amount of temperature rise that occurred in the exhaust stream. Now 
that we are specifying the temperature rise of the exhaust stream 
directly, it is not necessary to require a particularity high rate of 
air injection. Consequently we harmonized the amount of secondary air 
injection with the established RAT A procedure.
7. Adjusting Durability Procedures Based on IUVP Data (Comments 7 and 
8)
    Manufacturers commented that a defined approach of when and how to 
use IUVP data to adjust durability procedures is not appropriate. 
Furthermore they commented that EPA should not be concerned whether the 
durability process accurately predicts in-use emission deterioration if 
the manufacturer is complying with the standards in use.
    The CAP 2000 regulations specified that the in-use data collected 
under the in-use verification program (IUVP) testing provisions would 
be used to determine if the manufacturer's durability process was 
adequately predicting in-use emission levels (ref. 86.1823-01((g), and 
(h)). EPA continues to believe it is very important to compare actual 
in-use emission levels to the emission levels predicted at the time of 
certification and that this in-use information should be used to 
improve the durability process used to make those predictions.
    In the strawman procedures, EPA proposed calculating a least-
squares best-fit in-use DF for each durability group using the emission 
data from the IUVP. EPA suggested in the strawman process that its 
proposed durability regulation should contain a requirement that the 
manufacturer correct its durability prediction if the certification DF 
developed by the process for a specific durability group was 
significantly different from the in-use DF, or if there was a 
statistically significant general offset trend shown. The strawman 
proposal did not fully develop the procedures to be used to conduct 
this analysis. These offsets were to be corrected by either

[[Page 17546]]

mathematically adjusting the DFs by at least half the difference or 
increasing the number of miles/hours run during durability mileage 
accumulation/catalyst aging.
    The automotive industry commented that it would be very difficult 
to determine statistical significance, given the limited amount of in-
use verification data, and that this provision could place an 
unnecessary burden on those manufacturers who were over-predicting, 
rather than under-predicting emission deterioration. They also 
commented that as long as the in-use data was indicating that their 
vehicles were meeting the emission standards in use, that it should not 
be a concern to the Agency if the rate of deterioration calculated at 
the time of certification does not match that of in-use vehicles. They 
recommended that EPA retain the CAP 2000 regulations whereby the in-use 
verification data must be taken into consideration when deciding if the 
durability process is adequately predicting emission deterioration.
    EPA agrees that the approach taken in the CAP 2000 rulemaking is 
appropriate, because it provides a reasoned framework for when to 
require analysis and review by manufacturers, and provides the needed 
discretion for deciding when approval for a program should be withdrawn 
or modifications required. EPA still has the same concerns about 
durability accuracy expressed during the CAP 2000 rulemaking: ``An 
accurate durability process facilitates a more meaningful certification 
process which identifies noncompliance before the vehicles are produced 
and avoids excess in-use emissions. The in-use verification program is 
a tool which can be used by the Agency and the manufacturers to improve 
the durability process and avoid excessive emissions in use and costly 
recalls.'' \47\ It is the Agency's expectation when it issues an 
approval that a durability program will achieve the durability 
objective in use. EPA expects manufacturers to use the results of the 
IUVP testing to improve their durability projections when necessary to 
better achieve the durability objective.
---------------------------------------------------------------------------

    \47\ Ref. 63 FR 39663.
---------------------------------------------------------------------------

    As in the CAP 2000 program, EPA is proposing to require 
manufacturers to conduct an analysis of their durability program if 
certain objective criteria discussed below are met. In addition EPA may 
require such an analysis on a case by case basis even if the criteria 
are not met. EPA also reserves the authority to withdraw approval of a 
durability program or require its modification if it determines that 
the manufacturer's program does not meet the objectives for a 
durability program.
    The Agency is proposing to continue the requirement established in 
the CAP 2000 rule for the manufacturer to reevaluate the validity of a 
durability process in achieving the durability objective by performing 
an analysis when the average IUVP data exceeds 1.3 times the applicable 
emission standard and at least 50% of the test vehicles fail the 
standard in use (evaluated independently for all applicable emission 
constituents). These proposed analysis trigger criteria are 
intentionally loose enough to require an analysis only in cases where 
it is highly likely that durability programs that were failing to meet 
the durability objective. The Agency is also proposing that it may, at 
its discretion, require manufacturers to analyze available IUVP data, 
or other information, when it appears that the durability objective is 
not being achieved for some portion of the fleet of vehicles covered by 
a durability procedure regardless of whether the analysis trigger 
criteria have been met.
    As part of the analysis, the manufacturer should address the 
applicability of the data to current vehicle designs and to the current 
durability procedures used by the manufacturer. Manufacturers may 
remove from the sample the following types of unrepresentative data: 
(1) Data which was collected on an engine/emission control system which 
is not comparable to the current production designs, (2) data collected 
on a vehicle design which has been recalled (voluntarily or otherwise) 
due to a defective emission related part (unless the recall repair was 
performed on the test vehicle), or (3) data from vehicles that have 
been operated in an abnormal fashion that has impaired the 
effectiveness of the emission control system. In addition, 
manufacturers may also replace data from previously tested vehicles 
under the following conditions: (1) For in-use vehicles which have been 
primarily operated on high sulfur fuel (fuel with more than 80 ppm 
sulfur), if EPA has approved sulfur-removal preconditioning the 
manufacturer may replace the as-received testing with a second test 
conducted after sulfur-removal preconditioning has been performed, and 
(2) on a case-by-case basis, EPA may approve replacing the as-received 
testing performed on a vehicle which displays a MIL light that affects 
emission results with a second test performed after restorative 
maintenance has been performed. EPA would consider other exclusions or 
replacements of data on a case-by-case basis. The manufacturer may also 
provide additional in-use data with the analysis.
    As in the CAP 2000 program, EPA is proposing that it 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. In those cases, the Agency is proposing to 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. EPA may extend the 60-day period upon request by 
a manufacturer when it is necessary to complete a thorough analysis. 
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.
    These proposed requirements would apply to the EPA standard road 
and bench durability procedures as well as customized/alternative 
durability procedures.
    If the manufacturer was using the standard road cycle or standard 
bench cycle, EPA would require the manufacturer to adjust the 
durability process so it would achieve the durability objective. The 
Agency is proposing 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.
    If EPA determines that the SRC or the standard durability bench 
procedures generally do not meet the durability objective for a large 
number of manufacturers, EPA will adjust the standard procedures by 
rulemaking.

[[Page 17547]]

    As with the criteria for original approval of an alternative 
durability program, EPA considered a more stringent objective criteria 
for using IUVP data to evaluate durability procedures which would have 
required manufacturers to demonstrate that the durability procure 
resulted in (1) in-use emission results that are at least a specified 
percent less than or equal to the certification levels, and (2) at 
least 90 percent of the in-use emission data that pass the applicable 
emission standards. EPA is not proposing such criteria for the reasons 
described above regarding approval criteria.
8. Reproducibility by Outside Parties (Comment 9)
    We received comments supporting the goal that the public should be 
provided sufficient information to duplicate the deterioration results 
of any manufacturer-specified procedures that are CBI.
    In some cases, manufacturers have claimed that certain aspects of 
their manufacturer-specific durability procedures are confidential 
business information (CBI). As discussed above, the approval process 
for all alternative cycles includes a determination of the relative 
severity of the alternative cycles compared to the SRC by means of the 
calculation of an equivalency factor.\48\
---------------------------------------------------------------------------

    \48\ Refer to section II D 2 for a discussion of how to 
calculate the equivalency factor.
---------------------------------------------------------------------------

    EPA believes that a manufacturer's equivalency factor should not be 
considered confidential business information. The equivalency factor is 
developed using EPA-prescribed methods so there is no manufacturer 
practice to be protected. The factor relates to how much driving on the 
SRC is required to meet the durability objective. The SRC is a publicly 
available cycle developed by EPA. Furthermore, knowing that a certain 
amount of driving on the SRC produces the same amount of in-use 
emission deterioration as on the manufacturer cycle would not reveal 
any potentially confidential aspects of the manufacturers in-house 
durability procedures. For example, there would be many different road 
cycles that would result in the same equivalency factor to the SRC. EPA 
invites comment on whether the equivalency factor should be eligible 
for CBI treatment, including any justification for treating it as 
confidential. In the absence of a compelling justification to treat 
this equivalency factor as CBI, EPA intends to determine that a 
manufacturer's equivalency factor would not be considered CBI. 
Furthermore, EPA intends to publish a list of manufacturers which have 
obtained approval to use alternative cycles together with a 
manufacturer's equivalency factor for each test group which uses those 
cycles.
    The equivalency factor will provide the public with sufficient 
information to duplicate the amount of deterioration produced by a 
manufacturer-specific procedure. Even if a manufacturer asserts that 
their cycle is CBI, the public will have a pre-determined amount of 
mileage accumulation on the SRC that will result in an equivalent 
amount of emission deterioration. Consequently, any interested party 
could run the SRC for the appropriate number of miles and get the same 
results that the manufacturer developed during certification.
    To reproduce the deterioration generated by a manufacturer which 
certified using a customized 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).
9. Confidentiality of Emission Test Results Submitted Under the 
Durability Program
    Under the durability regulations, a variety of provisions require 
manufacturers to submit to EPA the results of emissions testing. For 
example, emissions test results are submitted as part of the approval 
process for alternative driving cycles. They may also be submitted 
subsequent to approval as part of an analysis of whether an alternative 
durability program continues to meet the objective of the durability 
program. The results of emissions testing are also submitted to EPA as 
part of the IUVP and confirmatory testing programs. Emissions test 
results would be submitted to EPA under 40 CFR 86.1823(e)(1)(A), 
86.1847(b)(1), and (f)(1). Emissions test results may also be submitted 
to EPA under other provisions of the durability regulation.
    EPA believes that the results of this emissions testing would be 
emissions data as defined by 40 CFR 2.301. Emissions data are not 
eligible for confidential treatment. 40 CFR 2.301(e). EPA invites 
comment on why these data should be eligible for CBI treatment. In the 
absence of a compelling justification received during the comment 
period, EPA intends to release emissions test results submitted to EPA 
as noted above. EPA is not attempting at this time to decide what other 
data, if any, would be emissions data under 40 CFR 2.301.

E. Diesel Vehicle Exhaust Deterioration

    EPA expects that diesel-fueled vehicles will be largely driven in 
the same fashion as gasoline-fueled vehicles. The SRC was developed to 
include sufficient amount of high catalyst temperature to age the 
catalyst on an Otto cycle engine. However, the same operation that 
causes high temperatures in catalysts also causes high engine load and 
high in-cylinder temperatures which increase engine wear in diesel 
vehicles and lead to emission deterioration. The SRC also contains a 
reasonable amount of slower speed operation and coast-downs followed by 
deep accelerations which increase lubricating oil consumption, fuel 
injection deterioration, and increase particulate formation. For these 
reasons, the SRC is considered to be fuel-neutral, that is, appropriate 
for any motor vehicle, regardless of the fuel used. Thus, the SRC may 
be used to evaluate exhaust emission deterioration of vehicles using 
any fuel. Furthermore, the provisions to customize the SRC or develop 
an alternative road cycle would for the same reason apply equally to 
vehicles, regardless of the fuel used.
    The same is not true for bench aging procedures, however. The bench 
procedures are only applicable to vehicles which use a catalyst as the 
principal exhaust emission control strategy. The proposed bench 
procedures accelerate the normal vehicle aging process by increasing 
the thermal aging of the catalyst. This strategy will not work 
acceptably for vehicles that do not have a catalyst, rely significantly 
less on the catalyst to provide emission reduction, or use after-
treatment devices that are significantly different from catalysts used 
on gasoline-fueled vehicles, e.g. NOX adsorbers or catalyzed 
particulate filters. For that reason the bench procedures proposed 
today are not applicable to diesel vehicles.
    As of the date of this proposal, EPA is not aware of any effective 
bench aging process for diesel vehicles. 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 proposed whole vehicle exhaust durability 
provisions.

[[Page 17548]]

F. Evaporative and Refueling Durability Procedures

    The CAP 2000 regulations for evaporative and refueling emission 
deterioration procedures are similar to the exhaust durability 
regulations, in that manufacturers had to propose a durability process 
for EPA approval. Our proposal incorporates procedures for determining 
evaporative and refueling emission deterioration levels.
    The proposed objective for the evaporative and refueling 
deterioration programs is the same one proposed for exhaust durability: 
to predict the expected evaporative and refueling emission 
deterioration of candidate in-use vehicles over their full useful life, 
covering a significant majority of deterioration. [Ref 40 CFR 86.1824-
01 for evaporative emissions and 40 CFR 86.1825-01 for refueling 
emissions].
    Unlike durability procedures to determine exhaust emission 
deterioration, EPA has never specified a standard procedure to 
determine evaporative emission deterioration. Instead, manufacturers 
were required to report to EPA evaporative deterioration factors that 
were ``designed and conducted in accordance with good engineering 
practice.'' [ref. 86.091-23(b)(2)]
    Since evaporative and refueling emissions are controlled by a 
similar vapor control system, the deterioration rates for evaporative 
and refueling emissions are generally determined using the same 
methods. Most vehicles use integrated refueling systems where a single 
charcoal canister handles both evaporative and refueling emission 
control.
    The factors affecting deterioration of evaporative control systems 
are different from those of exhaust emission systems. Evaporative and 
refueling emissions are controlled primarily by an activated-carbon 
canister. The canister stores the hydrocarbon (HC) fumes coming from 
the vehicle's fuel tank and fuel system. While the engine is running, 
the HC is purged from the canister and ingested by the engine. Other 
components which control evaporative emissions include fuel hoses and 
lines and the gas tank cap.
    To predict evaporative emissions deterioration, it is necessary to 
assess the useful-life performance of these vapor control components. 
Sources of potential deterioration are deactivation of the carbon in 
the canister, loss of carbon from the canister, degradation of hoses 
and lines due to environmental conditions (such as temperature extremes 
and exposure to ozone, ultraviolet light, and vibration), and fuel cap 
deterioration due to wear.
    Vehicle operating events that may lead to deterioration of the 
vapor control system include, (1) cycling of canister loading due to 
diurnal and refueling events, (2) vibration of components, (3) 
deterioration of hoses due to environmental conditions, and (4) 
deterioration of fuel cap due to wear.
    In addition, hosing used in fuel lines are subject to 
``permeation''--fuel vapors which seep out of microscopic pores in the 
material. Emissions due to permeation through the hoses generally 
stabilize after about a month of use and hence do not generally affect 
the long-term deterioration of the evaporative system.\49\ Beginning 
with the 2004 model year, EPA's ``Tier 2'' regulations include new, 
more stringent evaporative emission standards. Concern about the 
permeability effect of alcohol fuels on hoses and other evaporative 
components led EPA to require that manufacturers account for this 
effect in developing their evaporative durability processes [ref. 
86.1824-01(a)(iii), (iv) and (v)].\50\
---------------------------------------------------------------------------

    \49\ Refer to ``Fuel Permeation Rates of Elastomers after 
Changing Fuel'' by R. Stevens and R. Fuller of Dupont Dow, SAE No. 
970307.
    \50\ Numerous SAE papers examine the permeability of fuel and 
evaporative system materials as well as the influence of alcohols on 
permeability. See, for example SAE Paper Nos. 910104, 920163, 
930992, 970307, 970309, 930992, and 981360.
---------------------------------------------------------------------------

    Most of the potential causes of vapor control system deterioration 
are based on time rather than miles driven. Canister loading is caused 
mainly by diurnal events, the heating/cooling cycle that occurs over a 
24-hour day. For that reason, it is difficult to compress a full 
lifetime of diurnal events into a reasonable period of time on a whole 
vehicle.
    It is also desirable for cost reasons to combine a whole vehicle 
based evaporative/refueling deterioration evaluation with the whole 
vehicle exhaust durability program to save the expense of running two 
separate programs. For exhaust deterioration the important parameter is 
miles traveled following the SRC, for vapor control deterioration 
canister loading and purge events are more important. The whole vehicle 
exhaust durability program is generally completed in about 100 days. 
During that time, the vehicle would experience about 100 diurnals (one 
per day), which is much less than experienced during the vehicle's full 
useful life.\51\ A vehicle aged on the SRC would experience 
approximately the correct number of refueling events. While this 
shortfall in diurnal events could theoretically affect projections of 
deterioration, in actuality, the overall vapor control deterioration is 
so small that it does not significantly impact the deterioration rate 
calculation.
---------------------------------------------------------------------------

    \51\ Based on 7 to 10 years of use the number of lifetime 
diurnals would range from 2000 to 3500 events.
---------------------------------------------------------------------------

    Manufacturers have stated that evaporative emissions over the life 
of a vehicle do not generally increase. An EPA study of evaporative and 
refueling certification deterioration factors for the 2002 and 2003 
model years shows that these DFs are zero or close to zero for many 
vehicles.\52\ When there are evaporative or refueling failures in use, 
these failures can generally be attributed to failed parts or improper 
design rather than gradual increases in emissions due to deterioration.
---------------------------------------------------------------------------

    \52\ Refer to the TSD for a study of DFs for evaporative 
emissions. Most DFs were zero, the 70-percentile DF was 5% of the 
standard.
---------------------------------------------------------------------------

    EPA is proposing that manufacturers may determine their 
evaporative/refueling deterioration by adding evaporative and refueling 
tests to the SRC or an approved whole vehicle exhaust durability 
program. EPA is making this proposal knowing that the road cycle will 
not include a full lifetime of diurnal events. In making this decision, 
EPA is relying on the fact that the deterioration rates of current-
design evaporative system is very small and a more comprehensive 
procedure would not significantly improve the accuracy of predicting 
deterioration, but could significantly increase costs.
    EPA is also proposing that the evaporative/refueling deterioration 
may also be measured using a bench procedure. EPA is proposing that 
manufacturers evaluate the effects of certain sources of deterioration 
in the bench procedure. The manufacturer should establish an 
evaporative/refueling durability program that effectively covers a 
significant majority (approximately 90 percent) of in-use emission 
deterioration. A manufacturer may determine certification levels using 
a bench procedure when it determines (using good engineering judgement) 
that the bench procedure is more accurate than the SRC to achieve the 
durability objective. While the manufacturer does not need to submit 
their bench durability procedures for approval, EPA may review any 
certification level submitted during certification for its 
appropriateness. EPA is not promulgating specific methods to perform 
these evaluations. The emission deterioration sources that are proposed 
to be evaluated in the bench durability procedure are:

[[Page 17549]]

    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;
    5. Deterioration of fuel cap due to wear.
    Finally, EPA is proposing that it will allow manufacturers to 
determine evaporative and refueling DFs based on good engineering 
judgement without prior EPA approval.

III. What Is EPA Proposing Today?

    Today's proposal 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. The rationale for how the proposals in this section were 
developed is discussed in more detail in Section II. above.

A. Standard Whole Vehicle Exhaust Durability Procedure

    EPA is proposing 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 proposing 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 
proposing 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 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 proposing to retain 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 mileage accumulation. A minimum of one test at each of 
five different mileage points (total of five tests) are proposed.

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 
proposing a standard bench aging procedure that uses the BAT equation 
and the standard bench cycle (SBC) to reproduce emission deterioration 
from a road cycle. EPA's proposed standard bench procedure specifies 
that the SRC be used to generate the catalyst temperature histogram 
needed to determine bench aging time. Because the proposed 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 the 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 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 proposing 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 as follows 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):

01 to 40 secs:
    14.7 A/F, no secondary air injection
41 to 45 secs:
    Rich A/F ratio, no secondary air injection
46 to 55 secs:
    Rich A/F ratio, 3% ( 0.1%) secondary air 
injection
56 to 60 secs:
    14.7 A/F ratio, 3% ( 0.1%) secondary air 
injection

    The catalyst temperature (called the low control temperature) is 
controlled during the period of stoichiometric operation (Seconds 1 to 
40 of the cycle) to be 800[deg] C ( 10[deg] C). 
The A/F ratio during the ``rich'' phase of operation is selected \53\ 
to achieve a maximum catalyst temperature \54\ (called the high control 
temperature) over the cycle of 890[deg] C ( 
10[deg] C). If an alternative low control temperature is utilized (as 
allowed in the customization options, discussed below), the high 
control temperature is 90[deg] C ( 10[deg] C) 
higher than the low control temperature.
---------------------------------------------------------------------------

    \53\ A typical value of the ``rich'' A/F ratio is approximately 
13.5.
    \54\ The highest temperature generally occurs close to the 55-
second point in the cycle.
---------------------------------------------------------------------------

2. The Bench Aging Time (BAT) Calculation
    EPA is proposing a bench aging time (BAT) equation to calculate the

[[Page 17550]]

appropriate length of time to age a catalyst system on an aging bench 
to yield equivalent emission deterioration as running a vehicle on an 
approved 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 Section II, the BAT equation is based on the Arrehenius 
equation which relates chemical reaction rates with temperature. EPA is 
proposing the following BAT equation:

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 or a value determined by the manufacturer using in-use data and 
good engineering judgement to adjust the catalyst aging to include 
deterioration that may come 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. For cycles other 
than the SBC, the R factor must be determined experimentally using good 
engineering judgement. The manufacturer may also determine the R-factor 
experimentally for the SBC.
th = The time (in hours) measured within the prescribed 
temperature bin of the vehicle's temperature histogram adjusted to be 
on a full useful life basis (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 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
Tv = The mid-point temperature (in [deg]K) of the 
temperature bin of the vehicle on-road catalyst temperature histogram
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. EPA is 
proposing to calculate the effective reference temperature 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 is proposing that to obtain approval for a customized/
alternative road cycle the manufacturer would 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 proposing 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 (discussed in section III.C.3) when evaluating the 
cycle for approval.
    Once the durability process is approved, EPA is proposing that for 
each test group the manufacturer must determine, using good engineering 
judgement, whether to apply the durability procedure to that particular 
test group. Furthermore, EPA is proposing that 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
    EPA is also proposing to allow, subject to Agency approval, a 
limited degree of manufacturer customization of the standard bench 
procedures. However, in all cases EPA is proposing that alternative 
bench aging procedures be based upon measured vehicle performance (such 
as catalyst temperature) on an approved road cycle.
    Specifically EPA is proposing to allow customization of any or all 
of the following parameters when the accompanying conditions for 
approval are met:

[[Page 17551]]

    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 approved 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 effectively predict (or overstate) 
emission deterioration of a significant majority (approximately 90%) of 
future candidate in-use vehicles.
    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 (effective coverage of 90 percent of in-use emission 
deterioration) is not overstated by the worst-case fuel usage.
    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 approved 
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 approved road cycle.
3. Reproducibility by Outside Parties
    As discussed in the preceding sections, EPA is proposing that an 
alternative road cycle must be designed to achieve the durability 
objective proposed in this rule (effectively predicts a significant 
majority of the distribution of in-use emission deterioration on 
candidate in-use vehicles). As part of this evaluation, EPA is 
requiring in this proposal 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 in this proposal that every 
alternative bench aging procedure be based upon measured vehicle 
performance on a road cycle. Lastly, EPA is proposing to require 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 proposal is that, regardless of whether 
a manufacturer use 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. In the proposal, 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

    EPA is proposing to require a manufacturer to review its 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 is also proposing that it 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 is proposing that it 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 is proposing to 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 manufacturers 
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 would require the manufacturer to adjust the 
durability process so it would achieve the durability objective. The 
Agency is proposing 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

    For reasons described in section II. above, EPA is proposing that

[[Page 17552]]

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
    EPA is proposing that 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
    EPA is proposing that 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.
    EPA is also proposing that it will allow manufacturers to determine 
evaporative and refueling DF's based on good engineering judgement 
without prior EPA approval.

F. Effective Date and Carryover of Existing Durability Data

1. Effective Date
    Today's action is proposed to become effective with the 2006 model 
year. Because this is a Court-ordered action, we believe that the rule 
should take effect in the shortest amount of time possible that 
provides manufacturers with enough lead time to comply with the new 
regulations. We considered proposing a 2005 model year effective date, 
but we anticipate that the final rule will not be promulgated until 
March, 2004. By that time, many, if not all manufacturers will have 
completed the durability demonstration phase of their certification 
process for the 2005 model year (which traditionally is launched in 
Fall of the previous calendar year). Thus, a 2005 model year effective 
date would not provide manufacturers with enough lead time to complete 
their durability demonstrations. Therefore, we are proposing the 2006 
model year effective date which we believe provides adequate lead time 
for manufacturers to comply with today's proposed regulations.
2. Carrying-over Durability Data
    EPA is not proposing 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''. After the 2005 model 
year, if a manufacturer can meet these requirements, it may use 
existing durability data (i.e., DFs or aged hardware) that were 
approved prior to the vacature of the CAP 2000 regulations. Approved 
carry-over durability data may be used to support certification under 
the proposed rules.
    EPA is proposing that the manufacturer may not, however, continue 
to use CAP 2000 durability processes to generate new data starting with 
the 2006 model year. When the proposed rule becomes effective in the 
2006 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 
86.1823-06, 86.1824-06, and 86.1825-06), 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. Section 86.1824-07 was originally promulgated to add the 
applicability to 2007 model year and later MDPVs and HDVs. To improve 
readability, this applicability has been incorporated into 86.1824-06, 
and the original section is reserved.
    6. 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.
    As we drafted today's proposal, 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 proposal.
    In fact, it is possible that today's proposal 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 proposal).
    b. Reduced burden-hours per DDV. In addition to fewer DDVs, EPA 
also slightly reduced the estimated number of burden-hours required per 
DDV. As

[[Page 17553]]

above, this element was not affected by the Court mandate, and is not 
impacted by today's proposal.
2. Economic Impact of Today's Rule
    Today's proposal 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.\55\ 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.
---------------------------------------------------------------------------

    \55\ 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.
---------------------------------------------------------------------------

    Our proposed 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 fact that once approved, 
manufacturers will be able to use their existing durability programs 
without the need to make any changes to those programs.

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 proposal--the in-use verification program is not 
affected by the Court mandate, and no changes to this program are being 
proposed. EPA is proposing to modify an existing CAP 2000 provision 
whereby manufacturers utilize the IUVP data to assess the ability of 
the durability program to 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.

V. What Are the Opportunities for Public Participation?

A. Copies of This Proposal and Other Related Information

1. Docket
    EPA has established an official public docket for this action under 
Docket ID No. OAR-2002-0079. The official public docket consists of the 
documents specifically referenced in this action, any public comments 
received, and other information related to this action. Although a part 
of the official docket, the public docket does not include Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. The official public docket is the collection of 
materials that is available for public viewing by referencing Docket 
No. OAR-2002-0079 at the EPA Air Docket Section,(see ADDRESSES section 
above). You may submit comments electronically, by mail, or through 
hand delivery/courier as described below. To ensure proper receipt by 
EPA, identify the appropriate docket identification number in the 
subject line on the first page of your comment. Please ensure that your 
comments are submitted within the specified comment period. Comments 
received after the close of the comment period will be marked ``late.'' 
EPA is not required to consider these late comments. If you wish to 
submit CBI or information that is otherwise protected by statute, 
please follow the instructions in Section V.B.3 Do not use EPA Dockets 
or e-mail to submit CBI or information protected by statute.
2. Electronic Access
    You may access this Federal Register document electronically 
through the EPA Internet under the ``Federal Register'' listings at 
http://www.epa.gov/fedrgstr/.
    An electronic version of the public docket is available through 
EPA's electronic public docket and comment system, EPA Dockets. You may 
use EPA Dockets at http://www.epa.gov/edocket/ to submit or view public 
comments, access the index listing of the contents of the official 
public docket, and to access those documents in the public docket that 
are available electronically. Once in the system, select ``search,'' 
then key in the appropriate docket identification number.
    Certain types of information will not be placed in the EPA Dockets. 
Information claimed as CBI and other information whose disclosure is 
restricted by statute, which is not included in the official public 
docket, will not be available for public viewing in EPA's electronic 
public docket. EPA's policy is that copyrighted material will not be 
placed in EPA's electronic public docket but will be available only in 
printed, paper form in the official public docket. To the extent 
feasible, publicly available docket materials will be made available in 
EPA's electronic public docket. When a document is selected from the 
index list in EPA Dockets, the system will identify whether the 
document is available for viewing in EPA's electronic public docket. 
Although not all docket materials may be available electronically, you 
may still access any of the publicly available docket materials through 
the docket facility identified in Unit I.B. EPA intends to work towards 
providing electronic access to all of the publicly available docket 
materials through EPA's electronic public docket.
    For public commenters, it is important to note that EPA's policy is 
that public comments, whether submitted electronically or in paper, 
will be made available for public viewing in EPA's electronic public 
docket as EPA receives them and without change, unless the comment 
contains copyrighted material, CBI, or other information whose 
disclosure is restricted by statute. When EPA identifies a comment 
containing copyrighted material, EPA will provide a reference to that 
material in the version of the comment that is placed in EPA's 
electronic public docket. The entire printed comment, including the 
copyrighted material, will be available in the public docket.
    Public comments submitted on computer disks that are mailed or 
delivered to the docket will be transferred to EPA's electronic public 
docket. Public comments that are mailed or delivered to the Docket will 
be scanned and placed in EPA's electronic public docket. Where

[[Page 17554]]

practical, physical objects will be photographed, and the photograph 
will be placed in EPA's electronic public docket along with a brief 
description written by the docket staff.

B. Submitting Comments on This Proposal

    You may submit comments electronically, by mail, by facsimile, or 
through hand delivery/courier. To ensure proper receipt by EPA, 
identify the appropriate docket identification number in the subject 
line on the first page of your comment. Please ensure that your 
comments are submitted within the specified comment period. Comments 
received after the close of the comment period will be marked ``late.'' 
EPA is not required to consider these late comments.
1. Electronically
    If you submit an electronic comment, EPA recommends that you 
include your name, mailing address, and an e-mail address or other 
contact information in the body of your comment. Also include this 
contact information on the outside of any disk or CD ROM you submit, 
and in any cover letter accompanying the disk or CD ROM. This ensures 
that you can be identified as the submitter of the comment and allows 
EPA to contact you in case EPA cannot read your comment due to 
technical difficulties or needs further information on the substance of 
your comment. EPA's policy is that EPA will not edit your comment, and 
any identifying or contact information provided in the body of a 
comment will be included as part of the comment that is placed in the 
official public docket, and made available in EPA's electronic public 
docket. If EPA cannot read your comment due to technical difficulties 
and cannot contact you for clarification, EPA may not be able to 
consider your comment.
    a. EPA Dockets.
    Your use of EPA's electronic public docket to submit comments to 
EPA electronically is EPA's preferred method for receiving comments. Go 
directly to EPA Dockets at http://www.epa.gov/edocket, and follow the 
online instructions for submitting comments. To access EPA's electronic 
public docket from the EPA Internet Home Page, select ``Information 
Sources,'' ``Dockets,'' and ``EPA Dockets.'' Once in the system, select 
``Quick Search,'' and then key in Docket ID No. OAR-2002-0079. The 
system is an ``anonymous access'' system, which means EPA will not know 
your identity, e-mail address, or other contact information unless you 
provide it in the body of your comment.
    b. E-mail.
    Comments may be sent by electronic mail to [email protected], 
Attention Docket ID No. OAR-2002-0079. In contrast to EPA's electronic 
public docket, EPA's e-mail system is not an ``anonymous access'' 
system. If you send an e-mail comment directly to the Docket without 
going through EPA's electronic public docket, EPA's e-mail system 
automatically captures your e-mail address. E-mail addresses that are 
automatically captured by EPA's e-mail system are included as part of 
the comment that is placed in the official public docket, and made 
available in EPA's electronic public docket.
    c. Disk or CD ROM.
    You may submit comments on a disk or CD ROM that you mail to the 
mailing address identified in section I.C.2. These electronic 
submissions will be accepted in WordPerfect or ASCII file format. Avoid 
the use of special characters and any form of encryption.
2. By Mail
    Send your comments to: Air Docket, Environmental Protection Agency, 
Mailcode: 6102T, 1200 Pennsylvania Ave., NW., Washington, DC, 20460, 
Attention Docket ID No. OAR-2002-0079.
3. By Hand Delivery or Courier
    Deliver your comments to: EPA Docket Center, (EPA/DC) EPA West, 
Room B102, 1301 Constitution Ave., NW., Washington, DC., Attention 
Docket ID No. OAR-2002-0079. Such deliveries are only accepted during 
the Docket's normal hours of operation from 8:30 a.m. to 4:30 p.m., 
Monday through Friday, excluding legal holidays.
4. By Facsimile
    Fax your comments to: (202) 566-1741, Attention Docket ID. No. OAR-
2002-0079.
5. Submitting Comments With Proprietary Information
    Commenters who wish to submit proprietary information for 
consideration should clearly separate such information from other 
comments by (1) labeling proprietary information ``Confidential 
Business Information'' and (2) sending proprietary information directly 
to the contact person listed (see FOR FURTHER INFORMATION CONTACT) and 
not to the public docket. This helps insure that proprietary 
information is not inadvertently placed in the docket. If a commenter 
wants EPA to use a submission labeled as confidential business 
information as part of the basis for the final rule, then a non-
confidential version of the document, which summarizes the key data or 
information, should be sent to the docket.
    Information covered by a claim of confidentiality will be disclosed 
by EPA only to the extent allowed and by the procedures set forth in 40 
CFR Part 2. If no claim of confidentiality accompanies the submission 
when it is received by EPA, the submission may be made available to the 
public without notifying the commenters.

C. Areas Where EPA Specifically Requests Public Comment

    As discussed in the previous section, the public is invited to 
comment on any aspect of this proposed rule. The following are areas 
where EPA is specifically requesting comments:
    1. Whether the ``equivalency factor'' is properly classified by EPA 
as not CBI.
    2. What data provided by a manufacturer to obtain approval for an 
alternative cycle should or should not be classified as CBI.
    3. The appropriateness of the proposed durability objective 
(effective coverage of approximately 90 percent of the distribution of 
emission deterioration rate on in-use candidate vehicles). EPA would 
appreciate any data showing the degree of coverage for durability 
programs approved under CAP 2000.
    4. Whether the Standard Road Cycle (SRC) achieves EPA's durability 
objective. EPA would appreciate any emission and/or catalyst 
temperature data that demonstrates how the SRC compares to other 
cycles.
    5. EPA is interested in receiving any catalyst temperature or 
emission data that exists on the SRC or other mileage accumulation road 
cycles.
    6. The appropriateness of the Standard Bench Cycle (SBC). EPA would 
appreciate any catalyst temperature data and percent break-down of 
rich-lean-stoichiometric A/F ratios that support the comments.
    7. The appropriateness of the Bench Aging Time (BAT) equation (and 
its coefficients) for a manufacturers product line. EPA would 
appreciate catalyst temperature data paired with calculated aging times 
that support the comments.
    8. The appropriateness of the customization options and the 
approval process proposed.
    9. The ability of outside parties to use the equivalency factor to 
replicate the durability rates used by manufacturers during 
certification.
    10. The appropriateness of the IUVP data feedback provision of the 
proposal to accomplish the Agency's objective to assure accurate 
durability processes. EPA would appreciate any analysis of

[[Page 17555]]

in-use data under the proposed procedures that supports the comments.

D. Public Hearing

    Anyone wishing to present testimony about this proposal at the 
public hearing (see DATES) should notify the general contact person 
(see FOR FURTHER INFORMATION CONTACT)no later than five days prior to 
the day of the hearing. The contact person should be given an estimate 
of the time required for the presentation of testimony and notification 
of any need for audio/visual equipment. Testimony will be scheduled on 
a first come, first serve basis. A sign-up sheet will be available at 
the registration table the morning of the hearing for scheduling those 
who have not notified the contact earlier. This testimony will be 
scheduled on a first come, first serve basis to follow the previously 
scheduled testimony.
    EPA requests that approximately 50 copies of the statement or 
material to be presented be brought to the hearing for distribution to 
the audience. In addition, EPA would find it helpful to receive an 
advanced copy of any statement or material to be presented at the 
hearing at least one week before the scheduled hearing date. This is to 
give EPA staff adequate time to review such material before the 
hearing. Such advanced copies should be submitted to the contact person 
listed.
    The official records of the hearing will be kept open for 30 days 
following the hearing to allow submission of rebuttal and supplementary 
testimony. All such submissions should be directed to the Air Docket 
Section, Docket No. OAR-2002-0079 (see ADDRESSES). The hearing will be 
conducted informally, and technical rules of evidence will not apply. A 
written transcript of the hearing will be placed in the above docket 
for review. Anyone desiring to purchase a copy of the transcript should 
make individual arrangements with the court reporter recording the 
proceedings.
    If no one indicates to EPA that they wish to present oral testimony 
by the date given, the public hearing will be canceled.

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. EPA has submitted this action to 
OMB for review. Changes made in response to OMB suggestions or 
recommendations will be documented in the public record.

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 Act

    The Regulatory Flexibility Act generally requires an agency to 
conduct a regulatory flexibility analysis of any rule subject to notice 
and comment rulemaking requirements unless the agency certifies that 
the rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small not-for-profit enterprises, and small governmental jurisdictions.
    For purposes of assessing the impacts of today's rule on small 
entities, small entity is defined as: (1) A small business that 
manufacturers automobiles as defined by NAIC code 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; 
(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 proposed rule on 
small entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. 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 proposal. Thus, we have determined that 
small entities will not experience any economic impact as a result of 
this proposal. We continue to be interested in the potential impacts of 
the proposed rule on small entities and welcome comments on issues 
related to such impacts.

[[Page 17556]]

D. Unfunded Mandates Reform Act

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Pub. 
L. 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 proposed 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 
of the UMRA. Nothing in the proposed 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 proposed rule will impose no direct compliance costs on 
states. Thus, Executive Order 13132 does not apply to this rule.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between EPA and State and local 
governments, EPA specifically solicits comment on this proposed rule 
from State and local officials.

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 proposed 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 proposed by 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. 12866, and (2) concerns an environmental health or 
safety risk that EPA has reason to believe may have a disproportionate 
effect on children. If the regulatory action meets both criteria, the 
Agency must evaluate the environmental health or safety effects of the 
planned rule on children, and explain why the planned regulation is 
preferable to other potentially effective and reasonably feasible 
alternatives considered by the Agency.
    EPA believes this proposed rule is not subject to the Executive 
Order because it is not an economically significant regulatory action 
as defined by E.O. 12866.

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), Pub. L. 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 proposed rule does not involve consideration of any new 
technical standards. The durability test procedures that EPA is 
proposing are unique and have not been previously published in the 
public domain.

List of Subjects in 40 CFR Part 86

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

    Dated: March 16, 2004.
Michael O. Leavitt,
Administrator.
    For the reasons set out in the preamble, The Environmental

[[Page 17557]]

Protection Agency title 40, chapter I of the Code of Federal 
Regulations is proposed to be amended as follows:

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

    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

    2. Amend Sec.  86.1801-01 to add a new paragraph (i) to read as 
follows:


Sec.  86.1801-01  Applicability.

* * * * *
    (i) Optional chassis certification for diesel vehicles.
    (1) A manufacturer may optionally certify 2007 and later model year 
heavy-duty diesel vehicles under 14,000 pounds GVWR to the standards 
specified in Sec.  86.1816-08. Such vehicles must meet all requirements 
of Subpart S that are applicable to Otto-cycle vehicles, except for 
evaporative, refueling, and OBD requirements.
    (2) Diesel vehicles optionally certified under this section are 
subject to the OBD requirements of Sec.  86.005-17.
    (3) Diesel vehicles optionally certified under this section may be 
tested using the test fuels, sampling systems, or analytical systems 
specified for diesel engines in Subpart N of this part.
    (4) Diesel vehicles optionally certified under this section may not 
be included in any averaging, banking, or trading program.
    (5) The provisions of Sec.  86.004-40 apply to the engines in 
vehicles certified under this section.
    (6) Diesel vehicles may be certified under this section to the 
standards applicable to model year 2008 prior to model year 2008.
    (7) Diesel vehicles optionally certified under this section in 
model years 2007, 2008, or 2009 shall be included in phase-in 
calculations specified in Sec.  86.007-11(g).
    3. 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.
* * * * *
    4. 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
* * * * *
    SBC--Standard Bench Cycle
* * * * *
    SRC--Standard Road Cycle
* * * * *
    5. 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.
* * * * *
    6. Add a new Sec.  86.1823-06 subpart S to read as follows:


Sec.  86.1823-06  Durability demonstration procedures for exhaust 
emissions.

    This section applies to all 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 (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 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 mileage accumulation dynamometer.
    (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 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).
    (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

[[Page 17558]]

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.
    (iii) Catalyst temperature must be measured at the 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 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.
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.
    (B) Catalyst temperature must be measured at the 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 
judgment.
    (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.

[[Page 17559]]

    (2) This data set must consist of randomly procured vehicles from 
actual customer use. The vehicles selected for procurement will 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 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 sectiion. 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 approved 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 usage, 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 with the new bench cycle provides the same 
or larger amount of emission deterioration as the associated approved 
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 approved 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.

[[Page 17560]]

    (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 
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. The manufacturer must use good 
engineering judgment to determine that all exhaust emission-related 
components are designed to operate properly for the full useful life of 
the vehicles in actual use.
    (h) Application of the durability procedure to future durability 
groups. The manufacturer may apply a durability procedure to a 
durability group, including durability groups in future model years, if 
the durability process approved under paragraph (c) of this section 
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) The manufacturer may 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 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 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).
    (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

[[Page 17561]]

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 
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.
    7. A new Sec.  86.1824-06 is added to subpart S to read as follows:


Sec.  86.1824-06  Durability demonstration procedures for evaporative 
emissions.

    This section applies to 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 (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 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.

[[Page 17562]]

    (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. The manufacturer must use good 
engineering judgment to determine that all evaporative emission-related 
components are designed to operate properly for the full useful life of 
the vehicles in actual use.
    (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. 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.
    8. Remove Sec.  86.1824-07.


Sec.  86.1824-07  [Removed]

    9. Add a new Sec.  86.1825-06 to Subpart S to read as follows:


Sec.  86.1825-06  Durability demonstration procedures for refueling 
emissions.

    This section applies to 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 (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 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 of 
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 judgment.
    (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 another 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. The manufacturer must use good 
engineering judgment to determine that all refueling emission-related 
components are designed to operate properly for the full useful life of 
the vehicles in actual use.
    (i) If EPA determines based on IUVP data or other information that 
the durability procedure does not achieve the durability objective of 
paragraph (a)

[[Page 17563]]

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.
    10. 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.
* * * * *
    11. 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.  86.1823-06(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.
* * * * *
    12. Amend Sec.  86.1830-01 by revising paragraph (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.  86.1823-06(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.
    13. 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.
* * * * *
    14. 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.
* * * * *

[[Page 17564]]

    15. 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.  86.1823-06(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.
    16. 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 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]
* * * * *
    17. 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.
* * * * *
    18. Remove and reserve Sec.  86.1863-07.


Sec.  86.1863-07  [Reserved]

    19. 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
                                                                 accel
           Lap                         Description                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
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
------------------------------------------------------------------------


[[Page 17565]]

    The standard road cycle is represented graphically in the 
following figure:
[GRAPHIC] [TIFF OMITTED] TP02AP04.000

* * * * *

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

    1. The standard bench aging durability procedures [Ref. Sec.  
86.1823-06 (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,  None.
                               with load, spark
                               timing, and engine
                               speed controlled to
                               achieve a minimum
                               catalyst temperature
                               of 800[deg] C).
41-45.......................  ``Rich'' (A/F ratio    None.
                               selected to achieve
                               a maximum catalyst
                               temperature over the
                               entire cycle of
                               890[deg] C, or
                               90[deg] higher than
                               low control
                               temperature).
46-55.......................  ``Rich'' (A/F ratio    3% ( 0.1%).
                               a maximum catalyst
                               temperature over the
                               entire cycle of
                               890[deg] C, or
                               90[deg] higher than
                               low control
                               temperature).
56-60.......................  14.7 (stoichiometric,  3% ( 0.1%).
                               timing, and engine
                               speed as used in the
                               01-40 sec period of
                               the cycle).
------------------------------------------------------------------------


[[Page 17566]]

[GRAPHIC] [TIFF OMITTED] TP02AP04.001

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.  86.1823-06.

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 Attachment VII to Part 86. The SBC is 
repeated until the amount of aging calculated from the bench aging 
time (BAT) equation [ref. Sec.  86.1823-06 (d)(3)].

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 C. The 
BAT equation and the calculated effective reference temperature for 
the aging cycle [ref. Sec.  86.1823-06(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.

[[Page 17567]]

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-
06(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 (of the same catalyst design) at different 
control temperatures and measure catalyst efficiency periodically 
for each constituent.
    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-
06(d)(4).
    3. On the same set of axes, plot the percent of catalyst 
conversion efficiency along the vertical axis, versus hours of aging 
time on the horizontal axis for each of the catalysts. Draw a 
logarithmic best-fit line through the data for each aging 
temperature, as shown in the following graph.
[GRAPHIC] [TIFF OMITTED] TP02AP04.002

    4. On the plot of aging time versus conversion efficiency, draw 
horizontal lines at several different values of constant conversion 
efficiency. Where the horizontal line intercepts each of the 
constant temperature aging curves, read the corresponding aging time 
on the horizontal axis. The following graph shows an example of a 
horizontal line drawn for one value of constant conversion 
efficiency.
[GRAPHIC] [TIFF OMITTED] TP02AP04.003


[[Page 17568]]


    5. Plot the natural log (ln) of the aging time in hours along 
the vertical axis, versus the inverse of aging temperature (1/(aging 
temperature, deg K)) along the horizontal axis, for several 
constant-catalyst-efficiencies for each constituent. Fit least-
squared best-fit lines through the constant-efficiency data. The 
slope of the line is the R-factor. Use the smallest R-factor (worst 
case). See the following graph for an example.
[GRAPHIC] [TIFF OMITTED] TP02AP04.004

    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.

[FR Doc. 04-6297 Filed 4-1-04; 8:45 am]
BILLING CODE 6560-50-P