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Emission Durability Procedures for New Light-Duty Vehicles, Light-Duty Trucks and Heavy-Duty Vehicles
[Federal Register: January 17, 2006 (Volume 71, Number 10)] [Rules and Regulations] [Page 2809-2842] From the Federal Register Online via GPO Access [wais.access.gpo.gov] [DOCID:fr17ja06-9] [[Page 2810]] ----------------------------------------------------------------------- ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 86 [FRL-8019-2] RIN 2060-AK76 Emission Durability Procedures for New Light-Duty Vehicles, Light-Duty Trucks and Heavy-Duty Vehicles AGENCY: Environmental Protection Agency. ACTION: Final Rule. ----------------------------------------------------------------------- SUMMARY: This final rulemaking contains procedures to be used by manufacturers of light-duty vehicles, light-duty trucks, and some heavy-duty vehicles to demonstrate, for purposes of emission certification, that new motor vehicles will comply with EPA emission standards throughout their useful lives. Today's action defines procedures to be used by manufacturers to demonstrate the expected rate of deterioration of the emission levels of their vehicles. DATES: This rule is effective February 16, 2006. The information collection requirements of this rule have been approved by OMB and are effective February 16, 2006. ADDRESSES: EPA has established a docket for this action under Docket ID No. OAR-2002-0079. All documents in the docket are listed in the EDOCKET index at http://www.epa.gov/edocket. Although listed in the index, some information is not publicly available, i.e., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically in EDOCKET or in hard copy at the Air Docket, EPA/DC, EPA West, Room B102, 1301 Constitution Ave., NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744. FOR FURTHER INFORMATION CONTACT: General Contact: Linda Hormes, Vehicle Programs and Compliance Division, U.S. EPA, 2000 Traverwood, Ann Arbor, Michigan 48105, telephone (734) 214-4502, E-mail: hormes.linda@epa.gov. Technical Contact: Linc Wehrly, Vehicle Programs and Compliance Division, U.S. EPA, 2000 Traverwood, Ann Arbor, Michigan 48105, telephone: (734) 214-4286, E-mail: wehrly.linc@epa.gov. SUPPLEMENTARY INFORMATION: I. Background A. Overview of certification process, CAP 2000 history B. Durability demonstration process history 1. Durability demonstration methods used prior to the CAP 2000 regulations 2. Emission durability procedures under CAP 2000 C. Ethyl petition to reconsider CAP 2000 rules D. Judicial review of the CAP 2000 rules E. Applicability of the NPRM preamble discussion F. Supplemental notice regarding component durability II. Summary and Analysis of Comments A. The Durability Objective B. Evaluation of the certification durability procedures based on in-use emissions data C. Standard whole vehicle durability procedure 1. Standard Road Cycle (SRC) 2. Vehicle ballasting on SRC mileage accumulation 3. Calculating the DF from mileage accumulation of 75% of full useful life mileage 4. Testing required for DF calculation 5. Use of an engine dynamometer to recreate the aging on the SRC D. Standard Bench Aging Procedure E. Catalyst time-at-temperature data measurement F. Customized/Alternative durability procedures 1. Equivalency factors and alternative road cycles 2. Bench durability aging 3. Approval of customized/alternative durability procedures 4. Experimentally determining a customized R-factor 5. Alternative bench aging cycle content G. Component Durability H. Minor modifications to approved durability procedures I. Required notification to EPA that an approved durability procedure will be used for a particular durability group J. Public Availability of the equivalency factor and supporting data K. Carryover L. Evaporative Durability Procedures M. Starting model year for the rule N. Special provisions for new manufacturers O. Delete incorrect reference to intermediate useful life standards for the evaporative and refueling durability objective III. What is EPA promulgating today? A. Standard whole vehicle exhaust durability procedure B. Standard bench aging exhaust durability procedure 1. The Standard Bench Cycle (SBC) 2. The Bench Aging Time (BAT) calculation 3. The effective reference temperature for the SBC C. Customization of the standard procedures 1. Customization of the Standard Road Cycle 2. Customization of the standard bench procedures 3. Replication by outside parties D. Using In-Use Verification Program (IUVP) data to improve durability predictions E. Evaporative and refueling durability F. Effective date and carryover of existing durability data G. Miscellaneous regulatory amendments and corrections IV. What are the economic and environmental impacts? A. Economic impacts 1. Comparison to CAP 2000 economic impacts 2. Economic impact of today's final rule B. Environmental impacts V. What are the Statutory and Executive Order Reviews for this Rule? A. Executive Order 128866: Regulatory Planning and Review B. Paperwork Reduction Act C. Regulatory Flexibility Act D. Unfunded Mandates Reform Act E. Executive Order 13132 (Federalism) F. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments G. Executive Order 13045: Children's Health Protection H. Executive Order 13211: Actions that Significantly Affect Energy Supply, Distribution, or Use I. National Technology Transfer Advancement Act J. Congressional Review Act I. Background A. Overview of certification process, CAP 2000 history Before a manufacturer may introduce a new motor vehicle into commerce, the manufacturer must obtain an EPA certificate of conformity indicating compliance with all applicable emission standards over the vehicle's useful life period. The useful life for cars and light trucks is currently 100,000 miles or 10 years, whichever occurs first; for heavy light trucks, medium duty passenger vehicles (MDPV) and complete heavy duty vehicles the useful life period is 120,000 miles or 11 years, whichever occurs first. [Section 202(d) of the Clean Air Act and 40 CFR 86.1805-04] To receive a certificate, the manufacturer submits an application to EPA containing various information specified in the regulations, including emissions test data. EPA reviews the submitted information as well as any other relevant information, and issues a Certificate upon a determination that the manufacturer has demonstrated that its new motor vehicle will meet the requirements of the Clean Air Act (Act) and the regulations. [40 CFR 86.1848-01] A certificate of conformity is effective for only one model year; [[Page 2811]] therefore, new vehicle certification must occur annually. EPA's regulations detail the process motor vehicle manufacturers must follow to obtain EPA emissions certification. In 2000, EPA issued a comprehensive update to the certification regulations for light-duty vehicles and light-duty trucks.\1\ These certification regulations are known as ``CAP [Compliance Assurance Program] 2000''.\2\ They include detailed procedures on the selection of vehicles for testing and testing procedure, specifications on the information that must be submitted to EPA, and other requirements pertaining to reporting and testing. --------------------------------------------------------------------------- \1\ Separate certification regulations exist for heavy-duty highway vehicles and engines, which refer to the light-duty certification procedures. Today's final rule will apply to those subsets for heavy-duty vehicles which use the same certification procedures as light-duty trucks. for convenience, the term ``vehicle'' or ``motor vehicle'' will be used in this preamble to mean those light-duty and heavy-duty motor vehicles subject to these regulations. \2\ 63 FR 39654 (July 23, 1998). --------------------------------------------------------------------------- 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\ --------------------------------------------------------------------------- \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. --------------------------------------------------------------------------- The process of predicting how and to what degree a vehicle's emission levels will change over its useful life period [emissions deterioration] as well as the robustness of the vehicle's emission- related components [component durability] is known as an emission durability demonstration.\4\ Today's final rule specifies the methods that manufacturers must use to determine emissions deterioration for the purpose of certification. --------------------------------------------------------------------------- \4\ The durability demonstration program consists of two elements: emission deterioration and component durability. Emission deterioration prediction is a process of predicting to what degree emissions will increase during the vehicles useful life. The deterioration factor (DF) is a measure of deterioration. Component durability is a demonstration that the emission control components will not break and will continue to operate as described in the Application for Certification during the minimum maintenance interval proscribed in 40 CFR 1834-01. The component durability demonstration is conducted by the manufacturer using good engineering judgement. --------------------------------------------------------------------------- Over the years, EPA has promulgated regulations prescribing several different emissions durability demonstration methods to fulfill EPA's need to determine compliance with emission standards over the vehicle's full useful life. The following is a short summary of this prior regulatory history, to put today's final rule in context. B. Durability Demonstration Process History 1. Durability Demonstration Methods Used Prior to the CAP 2000 Regulations Prior to CAP 2000, EPA's regulations (ref. 40 CFR Part 86) specified the method to demonstrate a vehicle's emission durability. The method used a whole vehicle mileage accumulation cycle, commonly referred to as the Approved Mileage Accumulation (AMA) cycle. It required manufacturers to accumulate mileage on a pre-production vehicle, known as a durability data vehicle (DDV), by driving it over the prescribed AMA driving cycle for the full useful life mileage.\5\ This was to simulate the real-world aging of the vehicle's emissions control systems over the useful life. --------------------------------------------------------------------------- \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. --------------------------------------------------------------------------- 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. --------------------------------------------------------------------------- \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. --------------------------------------------------------------------------- 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\. --------------------------------------------------------------------------- \7\ Reference: 63 FR 39653, 39659 (July 23, 1998) (CAP 2000 NPRM). --------------------------------------------------------------------------- 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 [[Page 2812]] I (RDP I). It was an interim program scheduled to expire after the 1995 model year and was intended to serve as a bridge to an anticipated complete revision to the durability process. The provisions of RDP I were extended in a series of regulatory actions.\10\ Ultimately, the Agency instituted a comprehensive revision to the durability process as part of the CAP 2000 rulemaking. --------------------------------------------------------------------------- \8\ EPA approved three types of emission durability programs under these procedures: whole vehicle, full mileage, whole vehicle, accelerated mileage; and bench aging procedures which involved thermal aging of the catalyst-plus-oxygen-sensor system. \9\ Reference EPA Guidance Letter No. CD-94-13, ``Alternative Durability Guidance for MY94 through MY98'', dated July 29, 1994. This letter explained that as-received, un-screened in-use data should be compared to vehicles run on the alternative durability program (ASADP). A ``significant majority'' of the in-use data should be covered by the durability program. We defined the acceptance ceriteria in that letter as follows: ``EPA does not require ASADPs to meet a specific minimum severity level (or confidence level) because different methods may be used to estimate the degree of severity. * * * However, an ASADP would be acceptable to EPA if EPA believes that it were designed to match the in-use deterioration of 90-95 percent of vehicles in the engine family.'' \10\ Ref. 59 FR 36368 (July 19, 1994), 62 FR 11082 (March 11, 1997) 62 FR 11138 (March 11, 1997) and 62 FR 44872 (August 22, 1997). --------------------------------------------------------------------------- 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\ --------------------------------------------------------------------------- \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. --------------------------------------------------------------------------- 2. Emission Durability Procedures Under CAP 2000 The CAP 2000 rulemaking was a comprehensive update to the entire light-duty vehicle certification process. One part of this involved the manufacturer's required demonstration of emission durability. The Agency eliminated the requirement for the use of AMA for new durability demonstrations. In CAP 2000, the Agency replaced the AMA-based durability program with a durability process similar to the optional RDP-I program. Each manufacturer, except small volume manufacturers, was required to develop an emission durability process which would accurately predict the in-use deterioration of the vehicles they produce. The manufacturer had the flexibility to design an efficient program that met that objective. The manufacturer's plan was then reviewed by EPA for approval.\12\ Approval from the Agency required a demonstration that the durability process was designed to generate DFs representative of in-use deterioration. This demonstration was more than simply matching the average in-use deterioration with DFs. Manufacturers needed to demonstrate to EPA's satisfaction that their durability process would result in the same or more deterioration than is reflected by the in- use data for a significant majority of their vehicles. Manufacturers were required to provide evidence that their durability process resulted in predicted emission deterioration that were equal to or more severe than the deterioration rates experienced by a significant majority (approximately 90%) of candidate in-use vehicles.\13\ Furthermore, this demonstration was required to cover the breadth of the vehicles covered by the durability procedure. --------------------------------------------------------------------------- \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] --------------------------------------------------------------------------- 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. --------------------------------------------------------------------------- \14\ An engine dynamometer bench generally consists of an engine dynanometer, a ``slave'' engine, and required controllers and sensors to achieve the desired operation of the engine on the dynanometer. --------------------------------------------------------------------------- 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. --------------------------------------------------------------------------- \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. --------------------------------------------------------------------------- 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 [[Page 2813]] indicate the durability process underestimates in-use emission levels. --------------------------------------------------------------------------- \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]. --------------------------------------------------------------------------- The CAP 2000 regulations did not change the previous procedures used to obtain DFs for evaporative/refueling families. C. Ethyl Petition To Reconsider the CAP 2000 Rules On August 17, 1999, Ethyl Corporation petitioned EPA to reconsider the CAP 2000 regulations. EPA requested public comment on the petition, 64 FR 60401 (November 5, 1999 and 64 FR 70665 (December 17, 1999), and received comments from various interested parties. After consideration of the petition and of all comments, EPA denied the petition for reconsideration. 66 FR 45777 (August 30, 2001). Ethyl Corporation also petitioned the Agency to reconsider the final rule entitled ``Emissions Control, Air Pollution From 2004 and Later Model Year Heavy-Duty Highway Engines and Vehicles; Light-Duty On-Board Diagnostics Requirements, Revision; Final Rule,'' 65 FR 59896- 59978 (referred to here as the ``Heavy Duty Rule''). After consideration of the petition and all of the comments, EPA denied the petition for reconsideration. 66 FR 45777 (August 30, 2001). D. Judicial Review of the CAP 2000 Rules Ethyl Corporation petitioned for review of the CAP 2000 rulemaking, claiming among other things that the CAP 2000 durability provisions were unlawful as EPA had not promulgated methods and procedures for making tests by regulation as required by Sec. 206. [Ethyl Corp. v. EPA, 306 F.3d 1144 (DC Cir. Oct. 22, 2002).] In an opinion issued on October 22, 2002, the Court found that the CAP 2000 regulations did not satisfy the requirements of section 206(d) of the CAA to establish methods and procedures for making tests through regulation. The Court recognized that there was an important distinction between an EPA regulation that established general or vaguely articulated test procedures, with more specific details provided in a later proceeding, and a regulation which failed to establish any test procedures at all and only adopted procedures for the later development of tests. The former situation would receive deferential judicial review under the applicable case law. The latter case, however, would fail to meet the requirements of section 206(d). The Court held that the CAP 2000 regulations fell into this latter group, and were improper because EPA itself failed to establish any test procedures at all in the regulation, vaguely articulated or not. EPA's regulation provided only for the manufacturer to develop its own test procedure and submit it for later EPA approval. This was inconsistent with the scope of section 206(d), [Ethyl at 1149-50.] The Court also said that ``nothing in our opinion requires that EPA use only a `one-size-fits-all' test method. All that is required is that it establish its procedures, no matter how variegated, `by regulation.' '' [Ethyl at 1150.] Since the issue before the Court was the legality of EPA's adoption of the CAP 2000 durability provisions, EPA believes the court's vacature of ``the CAP 2000 program'' is limited to vacating the CAP 2000 durability provisions. The Court also remanded the case to EPA with instructions to establish test methods and procedures by regulation. Today's final rule is the result of the court's decision, and is limited to emission durability procedures. E. Applicability of the NPRM Preamble Discussion Unless otherwise indicated below, the discussion presented in the preamble to the notice of proposed rulemaking published at 69 FR 17532 is applicable to this final rule. F. Supplemental Notice Regarding Component Durability The Agency received a comment from Afton Chemical Corporation (``Afton,'' formerly known as Ethyl suggesting that EPA did not address the component durability portion of the emission durability process and should establish a procedure for determining component durability. After the Court decision which remanded EPA to write new regulations regarding emissions durability, EPA discussed with the Petitioner and automotive manufacturers the ramifications of that decision. To aid in these discussions, EPA provided a draft ``mark-up'' version of the CAP 2000 regulations, showing via stricken text exactly which regulations we believed had been vacated.\18\ We did not strike out the regulatory language regarding component durability. At that time, neither the petitioner nor the automotive manufacturers spoke out in opposition to this. We did not propose new procedures for component durability and proceeded with the proposed durability regulation, which retained the ``good engineering judgment'' language for component durability.\19\ Today's final rule includes only procedures for the emission deterioration portion of the durability process, because our understanding was that component durability was not at issue. However, Afton's comments are significant enough, that we believe it is appropriate to take the opportunity for further comment on component durability regulations. We believe it is appropriate, given the need for notice and comment for all interested parties, that we treat component durability in a separate action. Therefore, in addition to today's final rule, EPA is also today publishing a separate Supplemental Notice of Proposed Rulemaking requesting comments on a proposal which addresses component durability. Today's final rule has not revised the regulatory language for component durability. --------------------------------------------------------------------------- \18\ A copy of the strike-out version of CAP 2000 language is included in the Docket to this regulation. \19\ Ref. 69 FR 17533 ``EPA is not proposing to change the existing regulations for determining emission-related component durability''. --------------------------------------------------------------------------- II. Summary and Analysis of Comments EPA received comments from the automotive makers Ford, Volkswagen and Cummins, two automotive trade associations on behalf of their member automotive companies, the Afton Chemical Corporation (formerly know as the Ethyl Corporation), and one comment from a private citizen. The comments have been grouped together by subject matter. The following discussion presents the summary of EPA's proposal, of the comments received on that proposal, and EPA's response to those comments. A. The Durability Objective Summary of proposed rule. The proposed rules included a provision that defined the durability objective [Ref 40 CFR 86.1823-08(a)] as follows: ``The durability program must predict an expected in-use emission deterioration rate and emission level that effectively represents a significant majority (approximately 90 percent) of the distribution of emission levels and deterioration in actual use over the full and intermediate useful life of candidate in-use vehicles \20\ of each vehicle design which uses the durability program.'' --------------------------------------------------------------------------- \20\ Candidate in-use vehicles are vehicles selected under provisions of the in-use verification program (IUVP). This includes mileage restrictions, procurement requirements, and screening requirements designed to eliminate only tampered, mis-used or unsafe vehicles. [Reference: 40 CFR 86.1845-01 and 40 CFR 86.1845-04] --------------------------------------------------------------------------- Summary of Comments. The Alliance and AIAM commented that the phrase ``approximately 90 percent'' could [[Page 2814]] effectively increase the stringency of the standards by ignoring whether vehicles are passing the standards in-use and focusing on the probability distribution that in-use emissions exceed the emission levels projected at certification. This represents a substantial and unnecessary departure from the CAP 2000 rules. Instead, the rules should be in line with the ``significant majority'' goal espoused in CAP 2000 and the RDP guidance letter (CD-94-13, July 29, 1994). In response to a request by EPA to clarify their comments, the Alliance stated that they were concerned that the proposed provision in the regulations themselves which defined ``significant majority'' to mean ``approximately 90 percent'' could be interpreted to establish an inflexible percentage criterion and eliminate EPA's discretion to consider other factors when evaluating the effectiveness of a manufacturer's durability program taken as a whole. Response to Comments. The purpose of the durability program is to provide EPA with reasonable assurance that vehicles covered by a certificate of conformity will, in actual use, comply with the applicable emission standards over their full useful life. As discussed in the proposal, production variability or other reasons can lead to differences in actual emission levels among vehicles of the same nominal design. In the CAP 2000 rulemaking, EPA required that a durability program adequately predict emission deterioration for a significant majority of candidate in-use vehicles. In the CAP 2000 program, EPA had typically considered ``significant majority'' to mean approximately 90 percent coverage of the distribution of in-use deterioration. This concept was discussed in the preamble to the CAP 2000 rule \21\; however, EPA had not set a strict numerical criteria in the CAP 2000 regulations. --------------------------------------------------------------------------- \21\ Ref. CAP 2000 NPRM preamble 63 FR 39661. --------------------------------------------------------------------------- It was not the EPA's intention to establish in this rule a single rigid method or an inflexible numerical criteria to evaluate the durability objective. EPA understands the Alliance's concerns that the proposed language might lend itself to a more rigid interpretation that may limit EPA discretion and/or impose unintended burdens on manufacturers. Consequently, EPA has removed the parenthetical phrase ``approximately 90 percent'' from the finalized durability objective language in the regulations. By making this change we are not relaxing the requirement. The manufacturer must still demonstrate that a customized/alternative durability procedure is expected to effectively represent a significant majority of the distribution of emission deterioration in actual use to obtain EPA approval to use the procedure for certification. EPA and the manufacturers will still review IUVP data and/or other data to determine if the durability objective was achieved in use and whether it is appropriate to continue to use that durability process for future certification requests. EPA will consider a variety of different evidence and/or analyses that the durability objective has been or is expected to be achieved. However, a demonstration that approximately 90 percent of the distribution of in-use emission deterioration or emission levels is effectively represented by the durability procedure will continue to be a satisfactory showing for this purpose. The following section discusses how the durability objective will be used to evaluate certification durability procedures based on in-use emission data. B. Evaluation of the Certification Durability Procedures Based on In- Use Emissions Data Summary of Proposal. Manufacturers must use information gathered from the IUVP, as well as other sources of in-use emissions data, to periodically review whether the durability procedure it employs achieves the durability objective. EPA may require a manufacturer to perform an analysis to evaluate its durability procedure. EPA may withdraw approval of a durability procedure, or require modifications to the procedure, if the Agency determines that the durability objective is not being achieved by the durability procedure. [Ref. 86.1823-08 (i) and (j)] Summary of Comments. The Alliance and AIAM stated that they had concerns that a number of variables could affect IUVP emission data (including in-use fuel characteristics, mal-maintenance, testing variability, small sample size, random recruitment and as-received testing (rather than testing properly maintained and used vehicles)) and that these variables could affect the accuracy of decisions made using IUVP data. They stated that these concerns ``were already addressed in the CAP 2000 rulemaking in an appropriate fashion''. To illustrate their concern, the Alliance and AIAM provided this example: All in-use vehicles can be well below the applicable standards, but the durability procedure could be deemed deficient under the proposed rule merely because in-use emissions exceed the emission levels projected at certification. The Alliance and AIAM also suggested that ``If the IUVP data show that a manufacturer meets emissions standards in use (because, for example, the manufacturer certified with a sufficient compliance margin, known as ``headroom''), then the Agency should not be concerned and should not make decisions based on the accuracy of the certification emission deterioration seen in isolation.'' In response to a request by EPA to clarify their comments, the Alliance stated that the new provision could be interpreted to require changes in their durability programs even when a significant majority of candidate in-use vehicles comply with emission standards. They believed that the proposed rule could, therefore, effectively tighten the applicable emission standards. Ford commented that: (1) The proposal effectively increases the stringency of the standards. (2) The focus of this criteria appear to change from the strawman which compared the IUVP emission results to the standard and the highest certification level of all certification and running change tests. (3) Applying the 90 percent criteria [significant majority] criteria to IUVP data (``as received vehicles'') rather than ``properly maintained and used'' vehicles [the quality of data used to order recalls] further increase the stringency. (4) The proposed requirement forces change and cost increases to methods where 100% of the IUVP data meet applicable standards. (5) Reviewing the rate of deterioration is inconsistent with the use of certifying with aged components (rather than calculating a deterioration factor). The Alliance and AIAM also commented Review of durability processes should only be required when the in-use confirmatory test criteria are triggered. Response to Comments. EPA did not propose, nor are we finalizing, any changes to the IUVP testing program promulgated in the CAP 2000 rulemaking. As discussed in the proposal, EPA does not believe these provisions were vacated by the Court's decision and they remain effective without any further action required by the Agency. The provisions for using IUVP emissions data and/or other information to evaluate a durability procedure and for the Administrator to reject the use of a durability procedure based on such an evaluation were also contained in the CAP 2000 rules. The CAP 2000 rule established the requirement to reject a [[Page 2815]] durability procedure when ``the durability process has not been shown to effectively predict emission levels or compliance with the standards in use on candidate vehicles'' using this data. This requirement is practically equivalent to the ``not achieving the durability objective'' language in the proposal. As long as in-use vehicle data is below the standards, the durability procedure would be considered acceptable, even if the in-use emissions exceed the emission levels projected at certification. However, if it was found that the in-use emissions were significantly higher than the projected certification levels, we may decide to review the durability procedure to determine why the in-use emission results are so far off from the projected certification results in order to improve the procedure being used. We disagree with the comment that the comparison of IUVP emission data to the durability objective in the proposal is a new requirement (not contained in the CAP 2000 rules) that increases the stringency of the standards. As discussed in the last paragraph, the basis for the evaluation of a durability program in CAP 2000 was ``candidate in-use vehicle'' which are defined to be vehicles eligible for selection by the IUVP program. Clearly, comparing actual IUVP emission data to the durability objective is precisely what was intended by this requirement. Consequently, this requirement is not new and therefore does not increase stringency of the standards. Ford is confusing the ``well maintained and used'' quality of data requirement that applies to ordered recalls with the process of evaluating the effectiveness of a durability process for certification. As discussed in the CAP 2000 rule, EPA does not intend to order recalls of vehicles using unscreened IUVP data. EPA did not propose, nor are we finalizing, any provision that would change the process of ordering recalls of non-complying vehicles by using unscreened IUVP data. We continue to believe it is necessary to re-evaluate a manufacturer's durability process using actual in-use emission, data such as IUVP data, when that information becomes available. It is only through such review that we can be assured that the predictions made at the time of certification are actually valid in use. When that data indicate that the durability process does not achieve the durability objective in actual use, then the Agency may decide to withdraw approval for the durability procedure or require modification to the procedure for future certification purposes. Again, such remedial action is necessary for the Agency to assure an effective certification program. It would be reckless for the Agency to allow the continued use of a unmodified durability process for future certification once it has been shown to be ineffective in actual use for similar vehicles. We disagree with the suggestion that review of the durability procedures should only occur when the in use confirmatory program (IUCP) triggers \22\ are activated. The confirmatory test criteria are considered to be a screening criteria that identifies the very worst cases only for automatic reconsideration. EPA expects that there will be cases where the durability procedures are not working satisfactorily for a particular test group that are not identified by these criteria. Furthermore, reviewing in-use data in large groups allows the Agency to determine if there is an underlying trend that a durability process is not satisfactorily achieving the durability objective. In those cases, EPA is naturally and justifiably concerned about the accuracy of the durability process. These reviews conducted on a case-by-case basis are necessary for the Agency to assure an effective certification program. --------------------------------------------------------------------------- \22\ Mean In-Use Verification Program (IUVP) emissions for a test group exceed threshold of 1.3 times the certification emission standard and at least 50% of test vehicles for that test group fail for the same pollutant. --------------------------------------------------------------------------- EPA has retained the proposed provision to eliminate unrepresentative in-use data when making this determination. EPA has not established a single required method to perform an analysis to evaluate the effectiveness of the durability process using in-use emission data. The Agency will consider all information and analyses presented by the manufacturer submitted within the 60-day period specified in the regulations before reaching a final decision to withdraw approval for a durability procedure. Although there is no specified procedure for this evaluation, there are several observations which are applicable to this process. Calculating deterioration rates only from in-use emission results conducted at various vehicle mileage points on randomly procured vehicles within a test group can be misleading. It is well known that individual vehicle configurations within a test group or durability group will have different levels of absolute emissions. Since the IUVP uses random procurement, it is possible that the lower emission vehicles would be tested at low mileage and the higher emission vehicles would be tested at high mileage. This situation would lead to a exaggeratedly high calculated deterioration rate. This, in turn, could lead to the false determination that the durability process does not meet the durability objective. Comparing individual in-use emission levels to the certification levels or the applicable emission standards will result in more accurate evaluations of the in-use data and is recommended for that reason. It is better to make overall decisions about the effectiveness of a durability procedure using the largest possible data set of comparable vehicles. Consequently, EPA recommends performing analyses on a broad group of comparable vehicles rather than on single test groups or other small data sets. Comparable vehicles complying with different standards may be combined into the same analysis if the emission levels are standardized by the ratio of the emission standards. We agree with the Alliance and AIAM that the Agency should not make decisions based on the accuracy of the certification emission deterioration seen in isolation. Compliance margin should also be considered in the analysis. The proposed and finalized rules discuss ``effectively representing a significant majority'' (emphasis added). The word ``effectively'' in this context is intended to allow the use of compliance margin (also called ``headroom'') to expand the predictive coverage of a durability program. As stated previously, the purpose of the durability program is to provide EPA with reasonable assurance that vehicles covered by a certificate of conformity will, in actual use, comply with the applicable emission standards over their full useful life. This purpose may be accomplished by employing a durability process that directly predicts emission levels that represent a significant majority of the distribution of emission levels in actual use. Alternatively, the durability process may under-predict emission levels, but when coupled with the compliance margin, a significant majority of the vehicles comply with the emission standards in actual use. Providing that the same amount of compliance margin is used in future certification requests, it is reasonable to conclude that such a durability process when coupled with this level of compliance margin effectively represents a significant majority of the distribution of emission levels in actual use. For example: if after removing unrepresentative data only 70 percent of [[Page 2816]] the emission data was less than or equal to the predicted value (the certification level determined at certification time), then one could conclude that the predictive accuracy of the durability process was approximately 70% which would not constitute a ``significant majority''. If, however, when compliance margin is taken into account, 95% of the vehicles comply with the applicable emission standards, it could be safely concluded that a significant majority of vehicles are effectively represented by the durability procedure. Such an analysis would be performed separately for each applicable emission constituent and associated emission standard. Based on the preceding description of how the ``effectively represent'' criteria may be implemented, we disagree with the Alliance, AIAM, and Ford that the proposed requirements will result in the Agency withdrawing approving for a durability process when all the IUVP data is complying with the applicable standards. Lastly, we do not see an inconsistency, as a comment suggests, in comparing IUVP emission data to the durability objective when the manufacturer elects to certify using aged components rather than calculate a deterioration factor. EPA is allowing flexibility in the method for the manufacturer to conduct this analysis. EPA does not require (nor do we recommend, as discussed above) comparing certification DFs to DFs calculated from IUVP data. EPA's preferred method for the analysis involves comparing IUVP emission results to certification levels and standards; all of this data is available to manufacturers electing to certify with aged components rather than calculating a certification DF. In summary, the Agency is retaining the proposed requirement to require manufacturers to evaluate the durability procedures using in- use emission data generated on candidate vehicles (such as IUVP data) and the authority for EPA to withdraw approval of the durability procedure if the durability objective was not achieved in actual use on comparable vehicles. The Agency did not propose, nor are we finalizing, a specific required method to evaluate certification durability procedures based on in-use emissions data. However, a demonstration that approximately 90 percent of the distribution of in-use emission results (considering each emission constituent separately) comply with the applicable standard will be a satisfactory showing that the durability objective has been achieved. C. Standard Whole Vehicle Durability Procedure 1. Standard Road Cycle (SRC) Summary of Proposal. The standard whole vehicle durability procedure consists of mileage accumulation on a durability vehicle following the standard road cycle (SRC). The SRC was defined in the proposal in Appendix V of part 86. Summary of Comments. The Alliance and AIAM commented that the proposed standard road cycle is effective at meeting the Agency's intent. Response to Comments. Having received no adverse comments on the proposal, EPA is finalizing the SRC as proposed. 2. Vehicle Ballasting on SRC Mileage Accumulation Summary of Proposal. The proposed rules required that during mileage accumulation ``the durability data vehicle (DDV) must be ballasted to a minimum of the loaded vehicle weight for light-duty vehicles and a minimum of the ALVW for all other vehicles'' [Ref 86.1823-08(c)(1)(iii)]. Summary of Comments. The Alliance and AIAM suggested that EPA should harmonize the vehicle weight requirements for truck DDVs with the current emission testing requirements for emission data vehicles (EDV). Response to Comments. The proposal required heavier payload for truck mileage accumulation because trucks are designed to carry loads in addition to transporting the occupants of the vehicle. In our review of manufacturer vehicle design and durability processes, we found that trucks have special design and durability requirements acknowledging their load carrying capability. We also believe that trucks carry loads in actual use some fraction of the time. The standard whole vehicle durability program is designed to achieve the durability objective. The durability objective requires the durability program to represent a significant majority of the distribution of emission levels and deterioration experienced in actual use on those vehicles. To reach this goal of significant majority coverage, EPA believes that it is necessary to address heavier vehicle loads that occur in trucks some fraction of the time. The adjusted loaded vehicle weight (ALVW) loading requirement requires ballasting with half the payload rather than 300 pounds (the loaded vehicle weight which is applicable to light duty vehicle mileage accumulation in the proposal). The amount of ballasting for mileage accumulation should not be confused with the vehicle weight basis for conducting emission testing. EPA did not propose, nor are we finalizing, any change to the weight basis for emission testing, including testing that may be performed on the DDV to calculate a deterioration factor (DF). Although EPA continues to believe it is necessary to ballast most trucks to ALVW to assure that the durability objective is achieved, this requirement may to too severe for some light light-duty trucks.\23\ These lighter trucks are much more frequently used only for passenger transportation and more rarely used to transport significant payloads. Consequently, EPA is changing this provision in the final rule to require ballasting during mileage accumulation to a minimum of the loaded vehicle weight to apply to both light-duty vehicles and light light-duty trucks. We are retaining the provision to ballast all other vehicles to a minimum of the ALVW. --------------------------------------------------------------------------- \23\ Light light-duty trucks are trucks that are rated through 6000 pounds GVWR. This includes truck classes LDT1 and LDT2. --------------------------------------------------------------------------- 3. Calculating the DF From Mileage Accumulation of 75% of Full Useful Life Mileage Summary of Proposal. The description of the proposed standard whole-vehicle durability procedure contained a provision [Ref. 86.1823- 08(c)(2)] that would require mileage accumulation of at least 75% of the full useful life mileage. If the mileage accumulation was less than 100% of the useful life mileage this provision would require the DF to be based on the upper 80 percent statistical confidence limit calculated from the emission data. Summary of Comments. The Alliance and AIAM commented that projecting a full-useful life DF from data generated over 75% percent of the useful life is sufficient without adding the proposed 80% confidence factor. The proposed requirement is more stringent than the original CAP 2000 and Tier 1 requirement for projecting DFs. Projected full useful life emissions should use mean values rather than 80% statistical point. Response to Comments. We disagree. EPA promulgated the provision to allow reduced (75% rather than 100% useful life) mileage accumulation in the CAP 2000 and Tier 1 rules to address the concern of the excessive time necessary to complete full mileage accumulation with the AMA cycle. The excessive time concern has been addressed in the proposal by the SRC which is a [[Page 2817]] substantially faster \24\ cycle than the AMA cycle. For that reason, EPA had considered eliminating the provision to allow less than full useful life mileage accumulation altogether. Although the provision has been rarely used in the past, EPA thought it would be worthwhile to retain it in the standard whole-vehicle durability procedure providing that the reduced mileage accumulation did not adversely affect the quality of the projected DF. --------------------------------------------------------------------------- \24\ The fastest allowable AMA cycle (with a top speed of 70 MPH) has an average speed of 30.72 MPH while the SRC has an average speed of 46.26 MPH. The time necessary to complete 120,000 miles on the SRC [2594 run-hours] is less than time necessary on the AMA to complete 75% of the miles [90,000 miles take 2930 run-hours]. --------------------------------------------------------------------------- It is a basic statistical principle to apply a confidence factor when performing projections from a limited data set. The confidence factor addresses the added uncertainty inherent in not generating actual data for the last 25% of the mileage accumulation. The one-sided 80 percent limit is a loose requirement; it is not uncommon in projections to apply a confidence factor of 90% or higher. Running less than the full useful life mileage accumulation is voluntary. The need for this confidence factor is heightened now that Tier 2 has extended useful life to a maximum of 150K miles. The idea of allowing the 150,000 mile useful life as an option in Tier 2 [and thereby avoiding compliance with the intermediate useful life standards] is predicated on the assumption that the added emission data between 120,000 and 150,000 miles would improve our statistical confidence that the vehicles comply with full useful life standards. If we now (as suggested in this comment) allow manufacturers to project emission compliance without considering statistical confidence when only 75% of useful life mileage is run, then 150,000 durability could be demonstrated by running only 112,500 miles. Running 75 percent of the 150,000 miles [112,500 miles] is actually less breadth of data than the normal 120,000 miles and reduces our compliance confidence rather than enhancing it. Consequently, for the reasons discussed above, EPA is adopting its proposal to require the use of the upper 80 percent one-sided statistical confidence limit when less than full mileage accumulation is conducted using the standard whole-vehicle durability procedure. 4. Testing Required for DF Calculation Summary of Proposal. If a manufacturer elects to calculate a DF, then it must conduct at least one FTP emission test at each of five different mileage points selected using good engineering judgement. The required testing must include testing at 5,000 miles and the highest mileage point run during mileage accumulation. Additional testing may be conducted. [Ref. 40 CFR 86.1823-08(c)(3)] Summary of Comments. Manufacturers should be allowed to choose the number of tests for DF testing on the SRC, rather than the Agency mandating the use of five (or more) tests at different mileage points as proposed. Response to Comments. The reason for specifying a minimum number and distribution of test points to be used in calculating a deterioration factor is to assure a minimum level of confidence in the result of the calculation. It is possible that the same level of confidence could be achieved with multiple tests conducted at a fewer number of discrete mileage points. Since the intention of this requirement was to provide a minimum level of confidence in the DF, another plan that results in at least as much confidence would equally achieve this goal. To allow greater flexibility in deterioration testing plans, we are adding a provision in the final rule that would allow other testing plans providing the manufacturer determines, using good engineering judgement, that the alternative plan would result in equivalent or superior DF confidence interval. To justify such an alternative testing plan, the manufacturer would need to document that the alternative testing intervals result in a DF confidence interval equal to or better than the confidence interval using the testing plan specified in the regulations [one test at 5,000 miles, one test at full useful life mileage, and three equally spaced tests between 5,000 miles and the full useful life mileage]. 5. Use of an Engine Dynamometer To Recreate the Aging on the SRC Summary of Proposal. The proposal did not specifically address what type of dynamometer could be used for mileage accumulation on the SRC. The proposed regulation simply specified use of a mileage accumulation dynamometer. Summary of Comments. Cummins commented that vehicle mileage accumulation on the SRC could be effectively duplicated on an engine dynamometer by aging the complete engine and emission control system in an appropriate manner. They suggested that EPA allow the use of an engine dynamometer as an option for whole vehicle aging. Response to Comments. EPA agrees with Cummins that it is possible to replicate the aging that occurs on the SRC by installing a complete engine and emission control system on an engine dynamometer and appropriately controlling the engine load and other parameters during service accumulation. Although, this option was not prohibited in the proposal, EPA decided to clarify the language and specifically allow service accumulation on a engine dynamometer as an option method to conduct aging following the SRC. D. Standard Bench Aging Procedure Summary of Proposal. The standard bench aging procedure requires installation of the catalyst-plus-oxygen-sensor system on a catalyst aging bench. Aging on the bench is conducted by following the standard bench cycle (SBC) for the period of time calculated from the bench aging time (BAT) equation. The BAT equation requires, as input, catalyst time-at-temperature data measured on the SRC. This procedure was not applicable to diesel vehicles. Summary of Comments. The Alliance and AIAM commented that they believe that the standard bench cycle incorporates appropriate elements to provide an effective procedure to bench age exhaust emission hardware. Volkswagen commented that the proposed prohibition of bench aging procedure for use on diesel vehicles is inappropriate. The Agency should allow manufacturers the opportunity to propose an appropriate bench aging procedure for diesel vehicles which EPA would approve on a case-by-case basis. Cummins acknowledged that there is not an effective established procedure currently available for bench aging of diesel vehicles. However, they encouraged the Agency to provide some mechanism in the final rule that could allow approval of a bench aging procedure for diesels on a case-by-case basis at a later time without the need for further rulemaking. Response to Comments. Volkswagen's and Cummins suggestion that EPA allow a manufacturer to propose a bench aging durability procedure applicable to diesel vehicles without the Agency promulgating any description of the framework of the bench aging durability procedure for diesel vehicles in the regulations do not fulfill the Court's mandate. Nor does it fulfill the Clean Air Act requirement to establish methods and procedures for making [[Page 2818]] tests through regulation [Ref. CAA section 206 (d)]. None of the comments take issue with EPA's conclusion that the proposed bench aging procedures cannot be effectively used for diesel- fueled vehicles. The proposed bench aging procedures are designed to age the vehicle's catalyst-oxygen-sensor system as well as to replicate the total aging that occurs in use. Diesel vehicles to not employ catalyst technology as the principle emission control strategy, consequently the proposed bench aging procedure will not be effective for diesels. The comments did not suggest a bench aging procedure that was effective for diesel vehicles. In fact, Cummins acknowledged that there is not an effective established procedure currently available for bench aging of diesel vehicles. Consequently, EPA is retaining the proposed exclusion of diesel- fueled vehicles from employing the bench aging procedures finalized in these regulations. At a later date, EPA may choose to propose regulations providing bench aging procedures applicable to diesel- fueled vehicles. In the meantime, diesel-fueled vehicles must use the whole vehicle exhaust durability provisions. E. Catalyst Time-at-Temperature Data Measurement Summary of Proposal. EPA proposed that catalyst temperature must be measured at the highest temperature location in the hottest catalyst on the DDV. Catalyst temperature must be measured at a rate of one hertz (one measurement per second). Summary of Comments. The Alliance and AIAM commented that the measurement rate of catalyst temperature of 1 hertz should be changed to allow manufacturers to determine the appropriate rate. EPA should not dictate the location of catalyst temperature measurements. Determining the worst-case location is not practical. Response to Comments. Both of these measurement procedures only apply to the standard bench procedure and its elements. Manufacturers may use other procedures if using a customized/alternative process that does not use the EPA standard BAT equation, the standard aging bench design (as discussed in Appendix VIII) or EPA's standard method to experimentally determine a customized R-factor for the BAT equation (as discussed in Appendix IX). Because the measured temperature is the basis for calculating aging time or determining that the appropriate amount of aging has actually occurred on the aging bench, it is important to carefully specify where to measure the temperature. Temperatures can vary by over 100 [deg]C between various locations in a catalyst. In developing the BAT equation, EPA developed the equation based on measuring the maximum temperature in the catalyst. EPA has been receiving catalyst temperature data from manufacturers for many years which was measured at the hottest point in the catalyst to support carryover requests or to evaluate durability procedure approvals under RDP-I or CAP 2000. Typically, manufacturers have selected measure along the central axis of the catalyst about one inch back of the front face. This history indicates to the Agency that determination of the hottest location in the catalyst is practical. In Appendix VIII, EPA proposes that the measurement of catalyst temperature may be either at the highest temperature location or another location (providing the temperature is adjusted by a linear transform to represent the temperature measured at the hottest catalyst location). To address the practicality of actual measurement, EPA has modified the regulation language to correspond to the appendix. The temperature measured in a catalyst also can change quickly over time during the SBC. When EPA was developing the standard bench cycle we used time-at-temperature data recorded at a one hertz rate. The temperature measured in adjacent seconds frequently is different in these data sets. Consequently, EPA concluded that one hertz was the minimum acceptable frequency rate acceptable for this purpose. Faster measurement would be acceptable, because it would allow for more accurate measurement of the changing catalyst temperature. To allow faster measurement, EPA has changed the regulation from the proposal to specify that one hertz is a minimum frequency. F. Customized/Alternative Durability Procedures Summary of Proposal. Several of the comments received to the proposal discuss provisions that apply to different aspects of the customized/alternative durability procedures. As background for the discussion of these general comments, the following paragraphs summarize the provisions that were proposed for customized/alternative road cycles, calculation and use the equivalency factor, and customized/alternative bench aging durability procedures. Customized/Alternative Road Cycles. The Agency proposed that a customized or alternative road cycle could be used for certification if approved by the Administrator. The approval criteria require that the manufacturer demonstrate that whole vehicle mileage accumulation on the alternative/customized road cycle is expected to achieve the durability objective in actual use for the full range of vehicles to be covered by the procedure. The equivalency factor. The manufacturer must calculate an equivalency factor that equates the alternative or customized road cycle to the SRC run for full useful life mileage. The equivalency factor is used to determine how much in-use data the manufacturer must present in the analysis that the durability objective is expected to be achieved. The equivalency factor would also be made available to outside parties for their use to recreate aging conducted by the manufacturer during certification. For example, if the equivalency factor is 90% then the durability aging conducted by the manufacturer can be replicated by running the SRC for 90% of the useful life mileage or by bench aging using the SBC for the time calculated from the BAT equation using time-at-temperature data run on the SRC based on 90% of the useful life mileage. Customized/Alternative Bench Aging Durability Procedures. The Agency proposed that a customized or alternative bench aging procedure could be used for certification if approved by the Administrator. The proposal discussed seven types of customization allowable for the bench aging procedures and presented the criteria for their approval to the Agency. Specifically the Agency could approve the following customization to the standard bench aging durability procedure: ? Use a different lower-control temperature on the SBC providing the BAT equation was used to calculate the appropriate aging time. ? Use an customized R-factor in EPA's BAT equation providing that it is determined experimentally using the manufacturer's actual catalyst design. ? Use an customized A-factor in EPA's BAT equation, to ensure that the modified durability process will achieve the durability objective. ? Conduct bench aging using fuel with additional compounds that may lead to catalyst poisoning, such as phosphorus, sulfur or lead, rather than the standard fuel. ? Use an approved customized/alternative road cycle (rather than the [[Page 2819]] SRC) to develop catalyst temperature histograms for use in the BAT equation. ? Use a different bench cycle than the SBC with prior EPA approval. ? Use a different method than the standard BAT equation to calculate bench aging time with prior EPA approval. 1. Equivalency Factors and Alternative Road Cycles Summary of Comments. The Alliance and AIAM commented that it is pivotal that manufacturers be able to customize the standardized durability procedures. They support the equivalency factor approach because it provides the means for third parties to use the SRC to effectively replicate the aging effects produced by any manufacturer's durability protocols without requiring manufacturers to disclose proprietary engineering data and analysis. The equivalency factor, as proposed, also allows these customized/alternative procedures to be linked to the standard procedures. They do not object to the publication of the equivalency factors, themselves, but they comment that release of the underlying proprietary information is not required and is contrary to the Freedom of Information Act requirements. Afton (formerly known as Ethyl) commented that EPA must use appropriate rulemaking procedures which meet the requirements of section 307(d) of the CAA to adopt alternative road cycles rather than using the equivalency factor and the approval process discussed in the proposal. They acknowledge that the equivalency factor may provide a constructive means to attempt to balance the competing objectives of maintaining the secrecy of individualized certification test procedures, on the one hand, and disclosing to the public the test procedures on which the government relies to issue certification decisions, on the other. However, they state that the equivalency factor does not alter the Agency's obligation to promulgate alternative test procedures by regulation and include underlying data upon which the alternative test procedure is based. Consequently they believe that the proposed provision to allow the Agency to approve alternative road cycles does not meet the CAA requirements nor does it comply with the Court's mandate in Ethyl Corp. v. EPA. Response to Comments. We disagree with Afton's comments that the proposed regulations, which allow the Agency to approve alternative road cycles, do not meet the CAA requirements and do not comply with the Court's mandate in Ethyl Corp. v. EPA. The Court stated ``nothing in our opinion requires that EPA use only a ``one-size-fits-all'' test method. All that is required is that it establish its procedures, no matter how variegated, ``by regulation.'' That is what we have done in this rulemaking. We have established procedures that define the SRC as the standard whole-vehicle durability process. We have also described procedures to use a customized/alternative road cycle that is tied to a comparison of that cycle to the SRC and a demonstration that the cycle achieves the durability objective. In particular, the customized road cycle is the SRC run for a different distance. The actual distance run on a customized road cycle is the basis of the equivalency factor which EPA does not believe is confidential business information (CBI). The Agency plans to provide the equivalency factors to any interested party and post a listing on its Web site for public use. In the case of alternative cycles (cycles which use a different speed-versus-time trace than the SRC), we have also proposed (and are finalizing) durability procedures using those cycles. We have proposed procedures that specify the amount and type of data necessary for approval of such a cycle. We have proposed procedures that specify the approval method used by the Agency for approving the cycle. We have proposed procedures (the equivalency factor) to equate a customized cycle to the SRC. We have determined that the equivalency factor may be publically released. Furthermore, we have determined that if an outside party ran a vehicle on the SRC for the distance specified by the equivalency factor, the resulting deterioration would be equivalent to the manufacturer's durability showing using the customized road cycle. We have also proposed procedures that specify how to use the customized road cycle for calculating deterioration factors and/or conducting aged component testing. Lastly, we have proposed procedures for determining compliance using this data. In summary, in addition to the SRC, we have proposed and are finalizing, many details on the durability procedure for the use of customized road cycles. We believe we have clearly articulated a durability procedure (i.e., the SRC) by regulation fulfilling the mandate of the Court. We have also used our discretion in electing to describe most, but not all details, of the alternative road cycle durability process in the regulations. (See American Trucking Associations v. Department of Transportation, 166 F.3d 374 (DC Cir. 1999) and New Mexico v. EPA, 114 F.3d 290 (DC Cir. 1997). Agencies are entitled to broad deference in picking the suitable level of detail to specify in the regulations.) For the above reasons, EPA is finalizing the provision to allow alternative road cycles approved by the Administrator as proposed. 2. Bench Durability Aging Summary of Comments. Afton expresses concern that whether and how new systems perform in the field can directly impact operation of the catalyst in ways that may not be captured by thermal aging. They specifically cite the lack of aging of certain engine and fuel system components. They expressed concern that the analysis presented in EPA's draft technical support document (TSD) for the CAP 2000 proposal, which shows little engine-out deterioration, may be dated. Their concern is based on the fact that the analysis does not include vehicles using certain new technology devices and strategies which may, at some future time, begin to appear in production but which are not used in general production vehicles at this time. The Alliance and AIAM commented that the bench aging procedures incorporate appropriate elements to provide an effective method to bench age exhaust emission hardware. Response to Comments. We do not share Afton's concern that the proposed bench aging procedures may not be sufficiently accurate for certification purposes. The bench aging procedures are designed to effectively replicate the aging that occurs during in-use operation. As discussed in the preamble to the proposed rule, the bench aging procedures are required to be adjusted to duplicate the full emission deterioration that occurs in-use by thermally aging the catalyst. This may result in over-aging the catalyst to account for emission deterioration that occurs from other sources. The amount of over-aging may be large or small. The proposed BAT equation includes a term (the A-factor) which is used for this purpose. EPA has set the initial value of A as 1.1 based on the low expected engine-out deterioration identified in the TSD. However, if for any cause (including unexpected emission control deterioration of components not aged on the aging bench, or based on the future technology that Afton mentions in their comments), the bench aging durability does not achieve the durability objective, EPA has proposed a requirement that manufacturers change [[Page 2820]] the A factor to ensure that the durability goal is appropriately achieved by the bench aging process. Furthermore, EPA has proposed requirements that the manufacturer must periodically review their durability process to assure that the durability object is achieved in actual use. To facilitate this review, EPA requires manufacturers to provide IUVP emission data that must be used in this evaluation process. Lastly, EPA can require the manufacturer to change their durability process if the Administrator determines that the durability goal is not being achieved in actual use. Consequently, any risk that the bench aging process may not achieve the durability goal is controlled by this feedback process using IUVP emission data. For the above reasons, EPA is finalizing the standard bench aging durability procedures as proposed. 3. Approval of Customized/Alternative Durability Procedures Summary of Comments. The Alliance and AIAM made a series of comments to ``eliminate unnecessary and excessive administrative burden''. Specifically they suggested: Manufacturers should be allowed to self-approve a customized/ alternative durability road cycle if they can show it is more severe than the SRC. Manufacturers should not be required to submit data from 20 in-use vehicles to obtain approval, rather the manufacturer should review in- use data as it becomes available. The proposal requires the approval of a customized bench aging cycle even when the aging time is determined using the BAT equation. They suggest that this additional approval step is unnecessary and unjustified. EPA should eliminate all requirements for pre-approval and re- authorization of existing durability protocols absent in-use data which does not meet the existing requirements. Response to Comments. We disagree that the approval requirements of the proposal are either unnecessary or excessively burdensome. EPA must determine to its satisfaction that a potential customized/alternative durability process is expected to achieve the durability goal in use. Most of the durability procedures approved prior to the vacature of CAP 2000 rules were significantly changed based on the Agency's review and comment during the Agency's initial review. Although we now expect that most manufacturers have the skill necessary to design an appropriate customized/alternative process, we still believe that an initial review and approval by the Agency is still warranted. The proposal only requires an initial approval of the customized/ alternative durability process. Once a process is approved, the manufacturer must determine, using good engineering judgement, whether to apply the procedure to future durability groups. The proposal does contain provisions to require less in-use data for EPA approval when the customized/alternative cycle is shown to be significantly more severe than the SRC. We expect that approval of more severe cycles than the SRC to be granted, but the question still remains whether the customized/alternative cycle is severe enough to achieve the durability objective in use for the vehicles involved. Consequently, approval of a more severe customized/alternative cycle is not automatic. In the proposal, the amount of in-use emission data required for approval is varied depending whether the cycle is more or less severe than or approximately equivalent to the SRC. The amount of data required reflects the data necessary for the Agency to reach a valid conclusion to approve a cycle. As previously discussed, more severe cycles are rewarded in the approval process by a reduction in the amount of required data. The proposal requires approval of an alternative bench aging cycle because the distribution of air/fuel ratios and temperature is important to assure that adequate aging occurs. As discussed in the preamble to the proposed rule, a manufacturer must develop a new R factor if they change the bench aging cycle. Our standard R-factor applies only to the standard bench cycle (SBC). The determination of a customized R-factor is necessary because the same temperature exposure will result in a different amount of emission deterioration if the bench aging cycle is changed. The use of the standard BAT equation [with a different R-factor] provides no added assurance that the bench aging cycle will effectively replicate the emission deterioration that occurs on the associated road cycle as suggested in the comment. Consequently, EPA is finalizing the requirement to obtain Agency approval for alternative bench cycles. The proposed requirements are different than the CAP 2000 requirements, although the durability objective has not changed. Pertinent facts may have changed since the approval (under the CAP 2000 rules) of a particular durability procedure including production designs and the existence of more in-use data available for review. Although, the Agency expects that most of the durability processes that were approved prior to the court's vacature of the CAP 2000 rules will meet the requirements of this rule, we find no compelling case to make any blanket determination. Reviewing each durability process according to the new requirements on its own merits is an appropriate course of action for the Agency. Therefore, EPA is retaining and finalizing the proposed requirement that all customized/alternative durability procedures must be approved under the new rules (including all procedures used before the vacature of the CAP 2000 rules). 4. Experimentally Determining a Customized R-Factor Summary of the Proposal. EPA proposed that a manufacturer may determine an customized R-factor for use in the BAT equation. This would allow the BAT equation to be customized to better predict the required amount of bench aging necessary for a particular catalyst design. EPA proposed a standard experimental method for determining a customized R-factor in Appendix IX to the rule. EPA also proposed that other experimental techniques may be used if approved by the Administrator. To obtain approval the manufacturer must demonstrate that the calculated bench aging results in the same (or larger) amount of emission deterioration as the associated approved road cycle. Summary of Comments. The Alliance and AIAM commented that EPA's standard method for experimentally determining a R-factor [in Appendix IX] is overly restrictive and significantly increases the stringency of determining an R-factor. Ford commented that the approval procedure for using alternative techniques to experimentally determine the R-factor for the BAT equation should be based on accomplishing the durability objective rather than a comparison to the associated road cycle (the criteria in the proposal). Ford suggested an alternative standardized method to experimentally determine the R-factor that they felt would be more accurate and easier to implement. Their proposal (a detailed description is in the docket) suggested that emissions rather than catalyst efficiency be measured and that the emission deterioration projected from a least-squares regression of the emission versus time data be calculated directly from the experimental data rather than the two step process proposed by EPA. Response to Comments. EPA agrees that the standard method for [[Page 2821]] experimentally determining an R-factor supplied by Ford in their comments would be appropriate to use for that purpose. We also anticipate that it would be easier to generate the emission data required in Ford's alternative procedure than the conversion efficiency required in the proposed standard R-Factor determination procedure. Also this alternative approach eliminates one step compared to the proposed process. For those reasons, we have modified the Appendix in the final rule to allow this procedure. It should also be noted that other techniques, beyond the standard procedure outlined in Appendix IX to part 86, may be used as allowed in 40 CFR 1823-08(e)(2)(iii). Ford recommended that we take a step back from the proposed approval criteria which require ``that the calculated bench aging time results in the same (or larger) amount of emission deterioration as the associated approved road cycle.'' They recommended that we require instead that the manufacturer should demonstrate that the use of the R-factor would achieve the durability objective. One concern was that the proposed text seemed to require the existence of a customized/alternative road cycle because this would be the only cycle that was ``approved'', the SRC could be used without a specific Agency approval. It was not our intention to require that a manufacturer have an approved customized/alternative road cycle to determine an R-factor by an alternative method (rather than the standard method in Appendix IX to Part 86). Manufacturer may also use an alternative method to calculate an R-Factor when using the SRC as the associated road cycle to measure catalyst time-at-temperature data necessary to calculate aging time. It is our intention however, that a manufacturer must generate catalyst time-at-temperature data on either the SRC or an approved customized/alternative road cycle. Furthermore, that an alternative method will only be approved if it results in the same (or more) aging as that associated cycle. We believe that the approval criteria suggested by Ford (achieving the durability objective) will be functionally the same as the proposed criteria to replicate the aging seen on the associated road cycle but potentially less burdensome. For an alternative bench cycle to be approved the manufacturer must demonstrate that it achieves the durability objective. However, in the case where a manufacturer is using the SRC, it may not have the necessary in-use emission data to demonstrate that durability objective is being achieved. For these reasons, we continue to believe that the proposed requirement is a less burdensome and equally effective requirement as Ford's proposal. In today's final regulation text we have clarified that the road cycle used for comparison may be either the SRC or an approved customized/ alternative cycle. Otherwise, we have finalized the alternative R- factor methodology approval criteria as proposed. 5. Alternative Bench Aging Cycle Content Summary of Proposal. EPA did not propose any limitations on the content of an alternative bench aging cycle. EPA did propose that to obtain approval for such an alternative bench cycle the manufacturer must demonstrate that bench aging with the new bench cycle provides the same or larger amount of emission deterioration as the associated road cycle. Summary of Comments. The Alliance suggested that we clarify which provisions (in the proposed section 86.1823-08(e)(2)) pertain to manufacturers bench cycle and which provisions pertain to the EPA standard bench cycle. Response to Comments. EPA did not propose, nor are we finalizing, any limitations on the content of an alternative bench aging cycle. The alternative cycle may (among other differences) be of different length, have a different proportion of Air/Fuel ratios, different temperatures, different amounts of secondary air injection, and/or use no secondary air injection at all. However, whatever the content, the manufacturer must demonstrate that the alternative bench aging cycle works effectively by reproducing (or alternatively overstating) the aging that occurs on the associated road cycle which was used to measure the time-at-temperature data used to calculate the aging time on the aging bench. G. Component Durability Summary of Proposal. The proposal retains the CAP 2000 requirement that manufacturers use good engineering judgement to determine that all exhaust-related components are designed to operate properly for the useful life of the vehicles in actual use. Summary of Comments. Afton argued that EPA did not meet the requirements of the Act or the Court's mandate in Ethyl Corp. v. EPA, by not proposing test methods or procedures for assessing the durability of emission control system components, either separately for components, or for all the components operating together as an integrated system. In response to this comment, the Alliance and AIAM stated that there is no need to implement additional ``component'' durability test methods and procedures because the SRC re-establishes the requisite threshold level of stringency for the components as well as the system as a whole. They also claim that the Court did not impose any obligation on EPA to establish a whole new regime of component durability tests. Response to Comments. While EPA believes that Afton has raised an important issue, the NPRM did not contemplate any revisions to the component durability regulations. Therefore, EPA believes that before taking any final action on component durability, it is appropriate to open this issue to further comment. Therefore, concurrent with today's final rule, EPA is publishing a Supplemental Notice of Rulemaking (SNPRM) that addresses component durability. The SNPRM will seek comment on several options that EPA is considering for addressing component durability during the vehicle emissions certification process. After a formal comment period, EPA will consider any further comments received and issue a final rule. H. Minor Modifications to Approved Durability Procedures Summary of Proposal. The proposal contained a provision [ref. 86.1823 h) (1)] that allowed a manufacturer to modify an approved durability procedure by increasing or decreasing the number of miles run on an approved road cycle to represent full or intermediate useful life emissions deterioration or by changing the A-Factor in the BAT equation for a bench aging, using good engineering judgment, to ensure that the modified procedure will achieve the durability objective. Summary of Comments. The Alliance and AIAM commented that EPA should restore the CAP 2000 provision that allowed manufacturers to make minor modifications (using good engineering judgement) to an approved durability procedure without the need to obtain a new approval from EPA. Response to Comments. The proposal listed only certain changes that the manufacturer could make to an approved durability procedure using good engineering judgement without obtaining approval by the Administrator. Those changes were increasing or decreasing the number of miles run on an approved road cycle or changing the A-Factor in the BAT [[Page 2822]] equation. At that time, these were the only changes that the Agency envisioned that could be applied to the standard EPA durability procedures without considering the changes to constitute a customization of the standard procedures that would require Agency approval. We also proposed that these same changes could be made to customized/alternative durability procedures without requiring Agency approval. We agree that allowing some level of minor adjustments or changes to an approved customized/alternative manufacturer durability process would also be appropriate if the changes were limited in scope and made using good engineering judgement to assure that the modified durability procedures would achieve the durability objective. We believe that the level of adjustments allowed under CAP 2000 continue to be appropriate in the new durability regulations. In the vacated CAP 2000 durability regulations we stated: (1) Such modifications will be limited to incorporating additional data into the original algorithms of the approved durability process and (2) if a manufacturer wishes to change the algorithms used to determine the aging characteristics of the durability process, these changes will be considered a new durability process and will require advance approval by the Administrator. Therefore, we have modified the final regulation language to include a provision for manufacturers to make these minor changes, using good engineering judgement, without obtaining new approval from the Agency. I. Required Notification to EPA That an Approved Durability Procedure Will Be Used for a Particular Durability Group Summary of Proposal. The manufacturer must notify the Administrator of its determination to use an approved (or modified) durability procedure on particular test groups and durability groups prior to emission data vehicle testing for the affected test groups (notification at an annual preview meeting scheduled before the manufacturer begins certification activities for the model year is preferred). Summary of Comments. The Alliance and AIAM commented that the timing of the notification (prior to emission data vehicle testing) is too early in the certification process. They suggested that notification in the Application for Certification should be sufficient and is preferable to them. Response to Comments. The purpose of this requirement is to provide the Agency the necessary information about the manufacturers durability demonstration plans early enough in the certification process to be useful to the Agency. In particular, if the Agency wished to question the manufacturers judgement to apply a durability procedure to a particular durability group, it would be more efficient to raise this issue earlier in the certification process. Consequently, the Agency suggested that the notification occurs in the annual preview meeting which is typically scheduled before a manufacturer begins certification activity for a model year. As discussed in the current good engineering judgement provisions [ref. 40 CFR 86.1851-01 which is not being modified in today's final action] the Administrator may reject a manufacturers decision, even after certification is granted, if it is not based on good engineering judgement. Consequently, EPA agrees that notification at the time of the Application for Certification would provide the opportunity for sufficient oversight for the Agency. The risk to the manufacturer is that any questions regarding the good engineering decision basis of the manufacturers decision to apply a durability procedure to a certain durability group will come late in the process (or even after certification was granted). The good engineering judgement provisions in the current rule provide sufficient tools for the Agency to address these concerns in that time period. We still suggest that the best time for the notification is at the preview meeting to avoid last minute questions in the certification process. Nevertheless, we are changing the final regulation language to require the notification prior to or concurrently with the Application for Certification. J. Public Availability of the Equivalency Factor and Supporting Data Summary of Proposal. EPA proposed methods to calculate the equivalency factor. EPA also stated the opinion in the proposal that the equivalency factor was not confidential business information (CBI) and it may be released to the public. EPA also announced its plan to post the equivalency factors on the Agency's Web site. Summary of Comments. The Alliance agreed with the proposal that the equivalency factor is not confidential and may be released to the public. However, they stated that manufacturers should not be compelled to disclose to the public any of their underlying data or other proprietary information used to develop their durability process. The Alliance and AIAM also commented that EPA should not require extensive engineering reports justifying equivalency factors unless there is in-use or other data suggesting that the manufacturer's cycle does not achieve the durability objective. They also commented that manufacturers should only be required to supply equivalency factors for processes that are used in the future (after the effective date of the proposed rules). Afton commented that the Court's mandate Ethyl Corp. v. EPA, applies to all certification decisions made since the effective date of the mandate. Specifically, they disagreed with the Alliance and AIAM comment that equivalency factor need only be supplied for new durability procedures approved under the proposed rules and need not be reported for existing durability processes that were used after the vacature of the CAP 2000 rules as well as aging processes that were approved by EPA prior to the vacature. Response to Comments. EPA continues to believe that the equivalency factor is not confidential business information and may be released to the public. EPA renews its intention to post the equivalency factors on the Agency's Web site for public use. We are not making any other determinations (beyond the equivalency factor) regarding whether other information submitted by a manufacturer is or is not confidential business information. These decisions to release other information will be made on a case-by-case basis using the existing regulations [Ref. 40 CFR part 2]. We agree with Afton that the Court's mandate applies to all certification decisions made after the effective date of the mandate. However, once the Court's mandate became effective, EPA ceased requiring durability showings as a prerequisite to issuing a certificate of conformity. The basis for granting certification after the vacature of the CAP 2000 rule was EPA reliance on a statement made by the manufacturer using good engineering judgement that the vehicles in question will comply with the applicable standards for their full useful life. This statement was typically placed in the Application for Certification and has not generally been viewed by manufacturers as confidential business information. There are no approved durability procedures between the effective date of the Court's mandate and the effective date and model year of today's final rules. Consequently, there are no equivalency factors nor any supporting data that can be made [[Page 2823]] available by the manufacturers that apply to certification during that period. K. Carryover Summary of Proposal. EPA did not propose any changes to the carryover provisions in the current regulations (ref. 40 CFR 86.1839- 01). These provisions allow manufacturers to use durability data that was previously generated and used to support certification provided that the data ``represent a worst case or equivalent rate of deterioration''. EPA proposed that the manufacturer may not, however, continue to use CAP 2000 durability processes to generate new data starting with the effective date of the new regulations. When the proposed rule becomes effective, manufacturers must use durability procedures that have been approved under the new rules to generate new durability demonstrations. Summary of Comments. The Alliance and AIAM commented that, in addition to allowing carry over of existing durability data prior to CAP 2000 vacature, manufacturers should also be allowed to use existing durability data employed after vacature from previously approved processes conforming with good engineering judgment. They also suggested that manufacturers should be allowed to carry over aging data generated after the vacature of the CAP 2000 rules providing that these data were compiled using aged component processes approved by EPA prior to the vacature. Lastly, they commented that manufacturers should be allowed to continue to use aging processes approved by EPA prior to the vacature to age components on future data fleet vehicles. Response to Comments. EPA did not propose any change to the carryover provisions. After the effective date of the new regulations, if a manufacturer can meet these requirements, it may use existing durability data (i.e., DFs or aged hardware). This would apply to any data that exists prior to the effective date of the today's regulation which is compiled using a durability procedure that was approved prior to the vacature of the CAP 2000 rules. All new data generated after the effective date of today's rulemaking must meet all the applicable requirements including the requirement that it was generated using an approved durability procedure. L. Evaporative Durability Procedures Summary of Proposal. The proposal contained provisions for conducting evaporative durability using either a (1) whole vehicle demonstration using the SRC or another approved road cycle or a (2) bench aging demonstration using procedures contained in the regulations or (3) a combination of whole vehicle and bench procedures. Summary of Comments. The Alliance and AIAM commented that the Court's ruling dealt exclusively with tailpipe emissions and did not compel EPA to revisit evaporative durability. They also commented that separate durability demonstration for each evaporative family should be allowed via carryover using good engineering judgment. They also commented that EPA's right to revoke use of evaporative durability based on IUVP is not in keeping with CAP 2000, which said that EPA would use the data primarily for modeling purposes. They are concerned that the sample size is too small and would force manufacturers to ensure that IUVP evaporative emission test vehicles match the emission level of certification test vehicles. Non-fuel related emissions can not be represented in the certification durability process. Response to Comments. We disagree that the Court's decision regarding durability was limited to exhaust emission deterioration. Consequently, we proposed (and are finalizing) exhaust, evaporative, and refueling durability procedures. As discussed previously, the carryover procedures of the current regulations (ref. 40 CFR 86.1839-01) are not changed on the proposal. These provisions allow manufacturers to use durability data that was previously generated and used to support certification provided that the data ``represent a worst case or equivalent rate of deterioration''. Consequently, existing evaporative durability data and results may be carried-over providing they meet these requirements. We agree that the IUVP sample size (one test per test group) is too small to make this decision on an individual test group basis. However, EPA intends to review in-use evaporative data and evaluate the effectiveness of the durability process to achieve the durability objective when a reasonable amount of data does exist for this purpose. This expanded data set could include data from another source or it may consist of data combined from several related test groups or from several years of IUVP data. If the expanded data set indicates a problem, EPA believes it is appropriate to invoke this provision to re- evaluate the manufacturer's evaporative durability procedure. Furthermore, if the Agency ultimately concludes that there is sufficient data and that the data indicate that the durability objective is not achieved, EPA believes it is appropriate to require modifications to the durability procedure in the same method used for exhaust emission deterioration. It would not be acceptable to continue to use an evaporative durability process that was demonstrated to not achieve the durability objective; EPA relies on the accuracy of this data to make appropriate decisions to grant certification. Consequently, we are finalizing these provisions as proposed with the acknowledgment that a sufficient body of data must exist to make this determination with appropriate confidence. M. Starting Model Year for the Rule Summary of Proposal. EPA proposed that the rules would apply to 2006 model year vehicles certified after the effective date of the regulations. Summary of Comments. The Alliance and AIAM commented that the proposed effective date of 2006 model year (MY) should be changed to 2008 MY, or later if final rule published after August 2004. They stated that manufacturers are already doing durability testing on 2006 models, and developmental work is already underway for early introduction 2007 models. Volkswagen commented that the effective date of 2006 MY is unworkable, but they do not propose an alternative date. Ford commented that the effective date for the regulation should be changed to 2009 MY if component durability issues are addressed in a single rulemaking and 2008 MY if the emission deterioration provisions are finalized separately. The Alliance and AIAM suggest that we add a provision allowing early opt-in at the manufacturer's discretion. Response to Comments. We agree that 2006 is no longer possible given the current timing for publication of the final rule. Because publication of the FRM has taken longer than expected, and manufacturers are now certifying 2006 model year vehicles and already performing durability testing for 2007 models, we are delaying the implementation of the rule to become effective beginning with the 2008 MY. N. Special Provisions for New Manufacturers Summary of Proposal. EPA did not propose any special procedures for new manufacturers to obtain approval of a customized/alternative durability procedure. However, the standard procedures may be employed by these [[Page 2824]] manufacturers without generating any in-use emission data. Also, the Agency did not change the special certification procedures that apply to small volume manufacturers (ref. 40 CFR 86.1838-01). Summary of Comments. The Alliance and AIAM commented that new manufacturers should not have to rely on IUVP data for feedback purposes since they supply little or no IUVP data. They suggested that the rule should have clear provisions for new manufacturers. Response to Comments. New manufacturers may use the standard durability procedures without submitting in-use data or obtaining EPA approval. We believe that these standard procedures provide a reasonable method for new manufacturers to supply the required durability data without the need to compile in-use emission data. However, if a new manufacturer did wish to obtain approval for a customized/alternative durability road cycle, EPA would accept appropriate data from another manufacturer's comparable in-use vehicles to demonstrate the effectiveness of their durability procedures to achieve the durability objective. O. Delete Incorrect Reference to Intermediate Useful Life Standards for the Evaporative and Refueling Durability Objective Response to Comment. We made the appropriate correction in the final regulations. P. Comments From a Private Citizen Summary of Comments. One citizen submitted comments that touched upon various topics, many of which were not germain to the proposed rule. In general, the consumer believed that the proposal was ``too friendly'' to manufacturers. The commenter requested that the public should always be invited to all meetings EPA has with manufacturers to assure that no ``secret dealings'' are taking place. EPA response. Some of the comments touched on issues that have been addressed elsewhere in this section. We disagree that the proposal was ``too friendly'' to manufacturers. Emissions durability requirements impose a significant burden on manufacturers, and the provisions to allow for alternatives does not lessen the responsibility placed upon manufacturers to perform the required emission durability demonstration. We also disagree that all meetings with manufacturers should be open to the public. The discussions at these meetings center around individual manufacturers' business plans and are forward-looking in nature. Revealing these plans publicly would compromise the competitive automotive market. However, by informing the public of what sort of information is exchanged in these meetings, we believe we have provided the public with enough assurance that no ``deals'' are being made. III. What Is EPA Promulgating Today? Today's final rule includes two well-defined test methods for determining the exhaust emissions durability of vehicles from which manufacturers may choose: the standard whole vehicle aging process and the standard bench aging process. It also includes well-defined criteria allowing EPA to approve customization of or alternatives to these test methods, based upon a demonstration to EPA of the level of stringency needed to meet the durability objective, and the level of stringency demonstrated for the SCR and the customization or alternative. A. Standard Whole Vehicle Exhaust Durability Procedure EPA is promulgating a standard road cycle (SRC) which is targeted to effectively cover a significant majority of the distribution of exhaust emission deterioration rates that occur on candidate in-use vehicles. The SRC is fuel-neutral. It applies to all vehicles, regardless of fuel used. The SRC consists of seven laps of 3.7 miles each. The average speed on the SRC is 46.3 mph, the maximum cruise speed is 75 mph, and the acceleration rates range from light to hard accelerations. Most accelerations are moderate and there are no wide- open-throttle accelerations. The SRC contains 24 fuel-cut decelerations. The deceleration rates range from coast-down (no brake force applied) to moderate. EPA is promulgating a standard whole vehicle durability procedure which consists of running a vehicle (the durability data vehicle (DDV)) on the SRC for the full useful life mileage of the vehicle. We are also finalizing rules that manufacturers may terminate mileage accumulation at 75% of full useful life and project DFs based upon the upper 80% statistical confidence limit. The weight of the vehicle during SRC mileage accumulation is proposed to be the loaded vehicle weight (curb plus 300 pounds) for light-duty vehicles and light light-duty trucks. The weight basis for SRC mileage accumulation is the adjusted loaded vehicle weight ((curb + gross vehicle weight)/2) for all other vehicles covered by this rule. The fuel used on the SRC is proposed to be representative of commercially available gasoline (with a provision that extra poisoning may be added, such as phosphorus, sulfur or lead). EPA is retaining the CAP 2000 options of determining emission compliance levels by either (1) calculating deterioration factors (DF) and applying the DF to the emission data vehicle (EDV) emission results or (2) testing the EDV with emission control components aged using the SRC and installed prior to testing. If DF's are to be calculated, emission testing would be conducted at periodic intervals during milage accumulation. B. Standard Bench Aging Exhaust Durability Procedure Bench aging is a different way to achieve the same emission deterioration as whole-vehicle aging using a road cycle. EPA is promulgating a standard bench aging procedure that uses a bench aging time (BAT) equation and the standard bench cycle (SBC) to reproduce emission deterioration from a road cycle. EPA's standard bench procedure specifies that the SRC be used to generate the catalyst temperature histogram needed to determine bench aging time. Because the standard bench aging procedure relies on increasing catalyst thermal aging to account for all sources of emission deterioration, this procedure is not applicable to diesel fueled vehicles or vehicles which do not use a catalyst as the principal after-treatment emission control device. The standard bench aging durability procedure has been designed to reproduce the exhaust emission deterioration that occurs on the standard whole vehicle durability procedure. The standard bench aging procedure is as follows: a. Catalyst temperature data is measured at a minimum rate of one hertz (one measurement per second) during at least two replicates of the standard road cycle (SRC). The temperature results are tabulated into a histogram with temperature bins of no larger than 25 [deg]C. b. The effective reference temperature of the standard bench cycle (SBC), described below, is determined for the catalyst system and the aging bench which is to be used for the bench aging. c. The bench aging time is calculated using the bench aging time (BAT) equation, described below, using the effective reference temperature of the SBC and the catalyst temperature histogram measured on the SRC. d. The exhaust system (including the catalyst and oxygen sensors) is installed on the aging bench. The aging bench [[Page 2825]] follows the SBC for the amount of time calculated from the BAT equation. e. Catalyst temperatures and A/F ratios are measured during the bench aging process to assure that the proper amount of aging has actually occurred. Aging on the bench is extended if the aging targets are not properly achieved. 1. The Standard Bench Cycle (SBC) EPA is promulgating a standard bench cycle (SBC) which contains a mix of rich, lean and stoichiometric A/F ratios designed to achieve appropriate emission deterioration on the aging bench when operated for the period of time calculated from the BAT equation. The standard bench cycle consists of a 60-second cycle which is defined based on the A/F ratio of the engine (which is part of the aging bench) and the amount of secondary air injection (shop air which is added to the exhaust stream in front of the first catalyst). 2. The Bench-Aging Time (BAT) Calculation EPA is promulgating a bench aging time (BAT) equation to calculate the appropriate length of time to age a catalyst system on an aging bench to yield equivalent emission deterioration as running a vehicle on the associated road cycle. The standard bench aging durability procedure uses catalyst temperatures measured on the SRC to calculate the bench aging time necessary to reproduce the thermal exposure seen on the SRC. As discussed in the NPRM preamble, the BAT equation is based on the Arrehenius equation which relates chemical reaction rates with temperature. 3. The Effective Reference Temperature for the SBC The BAT equation uses a single temperature value called the effective reference temperature to represent the entire temperature- history experienced during the SBC on the catalyst aging bench. The effective reference temperature will be calculated using catalyst temperature histogram data measured in the catalyst on the aging bench following the SBC. The BAT equation would then be used to calculate the effective reference temperature by iterative changes to the reference temperature (Tr) until the calculated aging time equaled the actual time representing in the catalyst temperature histogram. The resulting temperature is the effective reference temperature for the SBC. C. Customization of the Standard Procedures 1. Customization of the Standard Road Cycle EPA has established criteria to obtain approval for a customized/ alternative road cycle that require the manufacturer to demonstrate that the objective of the durability program will be achieved for the breadth of the vehicles which are covered by the cycle. Approval of a customized/alternative road cycle requires a thorough analysis of whether the cycle will achieve the durability program objective using in-use emissions data, including a demonstration of the relative stringency of the SRC and the manufacturer's program. To make the initial demonstration necessary for the Agency to approve a customized/alternative cycle, EPA is requiring that the manufacturer supply high mileage in-use emission data on applicable candidate in-use vehicles. The vehicles would be randomly procured from actual customer use, generally with an age of 4 to 5 years and with a minimum of approximately 50,000 miles. They would cover the breadth of the vehicles that the manufacturer intends to certify using the customized/alternative cycle. Vehicles would be procured and FTP tested as received under the provisions of the IUVP program (ref: 40 CFR 86.1845-04). Manufacturers could use previously generated in-use data from the CAP 2000 high mileage IUVP program or the fourth-year-of- service RDP ``reality check'' in-use program as well as other sources of in-use emissions data for this purpose. EPA will also consider additional emissions data or analyses that the manufacturer may choose to provide, including data from vehicles which have been screened for proper maintenance and use. The amount of in-use emission data required for this analysis is based on whether the customized/alternative cycle is more or less severe than the SRC. In most cases, EPA will accept a minimum of 20 candidate in-use vehicles. There is less risk of underestimating actual in-use emission levels when the customized/alternative cycle is more severe than the SRC. However, if the customized/alternative cycle is significantly more severe than the SRC, EPA may accept less data. Conversely, if the customized/alternative cycle is significantly less severe than the SRC, EPA may require more data up to a maximum of 30 vehicles. EPA will also consider the equivalency factor of the customized/ alternative cycle when evaluating the cycle for approval. Once the durability process is approved, the manufacturer must determine, using good engineering judgement, whether to apply the durability procedure to a particular test group. The manufacturer may make modifications to an approved customized/alternative road cycle and apply them to a test group to ensure that the modified process will effectively achieve the durability objective for future candidate in- use vehicles. The manufacturer would be required to identify such changes in its certification application and explain the basis for the changes. Manufacturers must use good engineering judgement in making these decisions. Significant, major, or fundamental changes to a customized/alternative cycle would be considered new cycles and would require adv