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Durability Compliance Program
The goal of the Durability Compliance Program is to ensure that manufacturer durability programs accurately predict in-use emission levels and deterioration rates for vehicles they wish to certify. The predictions must reflect in-use vehicle field data and engineering knowledge of the emission control system. The following information is designed to assist manufacturers as they demonstrate compliance with emission standards for the intermediate and full useful life of a vehicle.
Manufacturers may use accelerated deterioration methods and artificial aging techniques to simulate wear on vehicle and emission system components. Manufacturers may also use proprietary aging cycles to conduct their durability program. All manufacturer durability program plans must be submitted to EPA annually for review and approval. In addition, manufacturers that use a unique aging cycle for durability demonstration purposes must develop an equivalency factor (read Equivalency Factors below for more details) that equates their cycle to a standard EPA aging cycle. Specifically, the equivalency factor relates the amount of aging performed on the unique road or bench aging cycle to the amount of aging that occurs over EPA's standard cycles.
EPA will provide a list of manufacturer equivalency factors and other applicable vehicle information for each model year on this web site.
For durability compliance questions please contact: Arvon L. Mitcham at 734-214-4522 (mitcham.arvon@epa.gov) or Lynn Sohacki at 734-214-4851 (sohacki.lynn@epa.gov).
NOTE: You will need Adobe Acrobat Reader, available as a free download, to view some of the files on this page. See EPA's PDF page to learn more about PDF, and for a link to the free Acrobat Reader.
Regulations
Final Rule and Supplemental Notice for Durability Procedures for New Light-Duty Vehicles, Light-Duty Trucks, and Heavy-Duty Vehicles (Published January 17, 2006)
- Final Rule: Emission Durability Procedures for New Light-Duty Vehicles, Light-Duty Trucks and Heavy-Duty Vehicles
- Final Rule (also available as a PDF file, 156 pp, 575K)
- Fact Sheet: Final Rule for Emissions Durability Test Procedures (PDF) (3 pp, 33K, EPA420-F-05-061, December 2005)
- Supplemental Notice of Proposed Rule: Component Durability Procedures for New Light-Duty Vehicles, Light-Duty Trucks and Heavy-Duty Vehicles
- Supplemental Notice of Proposed Rule (also available as a PDF file, 66 pp, 187K)
- Fact Sheet: Supplemental Notice of Proposed Rule (PDF) (2 pp, 33KB, EPA420-F-05-062, December 2005)
Proposed Final Rule for Durability Procedures for New Light-Duty Vehicles, Light-Duty Trucks, and Heavy-Duty Vehicles (Published April 2, 2004)
This rulemaking fulfills a court mandate issued on October 22, 2002, by the United States Court of Appeals for the District of Columbia Circuit that ordered EPA to issue new emissions durability regulations. Contact: Linda Hormes (734-214-4502) hormes.linda@epa.gov.
- Proposed Preamble and Regulations (Also available as a PDF file, 38 pp, 415K)
- Proposed Technical Support Document (PDF) (5 pp, 30K) and the Attachment (PDF) (152 pp, 7.3MB)
- Fact Sheet: Proposed Rule for Emissions Durability Test Procedures (PDF) (3 pp, 104K, January 2004, EPA420-F-04-013)
Final rule for Extension of Interim Revised Durability Procedures for Light-Duty Vehicles and Light-Duty Trucks (Published August 22, 1997)
Proposed rule for Extension of Interim Revised Durability Procedures for Light-Duty Vehicles and Light-Duty Trucks (Published March 11, 1997)
- Proposed Rule
- Extension of Interim Revised Durability Procedures for Light-Duty Vehicles and Light-Duty Trucks
Guidance
CISD-07-05
Manufacturer Guidance on Compliance Demonstration with the Emissions Durability Procedures and Regulations (PDF, 5 pp, 49K)
Equivalency Factors
The purpose of equivalency factors is stated in the preamble language contained in the January 17, 2006, 71 FR 2818, Final Rule (also available as a PDF file, 156 pp, 575K).
Manufacturers have three options to demonstrate full useful life durability (120,000 or 150,000 miles) of their vehicles and emission control components:
- EPA Standard Road Cycle or Standard Bench Cycle (SRC/SBC): EPA developed the Standard Road Cycle (EPA SRC: 40 CFR Part 86, Appendix V) and the Standard Bench Cycle (EPA SBC: 40 CFR Part 86, Appendix VII and Appendix VIII) to provide a universal road/bench aging cycle. These cycles are available to all manufacturers for purposes of demonstrating durability. Manufacturers may use a standard EPA cycle without prior EPA approval but must inform EPA of their intent to do so when they submit their durability plan for review.
In addition, EPA has developed a "Bench Aging Time" calculator that outputs the bench aging hours necessary on the SBC to replicate aging and deterioration that would occur on a road cycle (either the SRC or a manufacturer's alternative cycle).
- Alternative Road or Bench Cycles (ARC/ABC): Manufacturers may design their own cycles to mimic the aging or deterioration of emission control components that would occur on real-world vehicles over their useful life. These cycles are typically designed to reproduce useful life aging/deterioration in a shorter period of time. The manufacturer can choose to age the emission control components on the vehicle (i.e., whole vehicle aging) or, to reduce cost and test burden, use a test bench to age the emission control components (i.e., bench aging). Manufacturers must obtain prior EPA approval to use an alternative road or bench cycle.
- Customized Standard Road Cycle or Standard Bench Cycle (Cust. SRC/SBC): Manufacturers may also customize the EPA SRC/SBC to fit their specific in-use vehicle fleet aging/deterioration rates (e.g., higher speeds regimes to achieve more deterioration within the full useful life) or unique test facilities (e.g., shorter or longer test track lengths). These methods also require prior EPA approval.
The standard EPA bench and road cycles represent a baseline or measuring stick for all other cycles since they can be applied to all vehicles. Manufacturer-derived alternative or customized cycles may be more or less severe than the SRC/SBC, depending on the design of the cycle. Therefore, EPA requires manufacturers to develop an equivalency factor, or EF, that can be used for comparison. Specifically, the EF is the ratio of the SBC bench aging hours for a manufacturer-derived alternative or customized cycle and the SBC bench aging hours for the SRC, at the applicable full useful life mileage.
Specific details on how to calculate and use the EF are provided in Manufacturer Guidance on Compliance Demonstration with the Emissions Durability Procedures and Regulations (PDF, 5 pp, 49K). Note that manufacturers using the EPA SRC and/or SBC for durability demonstration will simply have an equivalency factor of 1.0.
The equivalency factors must be provided by manufacturers of light-duty vehicle, light-duty trucks and heavy-duty vehicles each model year and will be published semi-annually on this site.
Presentations
- Emissions Durability Rule Implementation Presentation from May 17, 2006 EPA Industry Meeting (PDF) (12 pp, 33K)
- Emissions Durability Rule Implementation Presentation from November 29, 2006 EPA Industry Meeting (PDF) (12 pp, 33K)
- Emissions Durability Rule Implementation Presentation from April 26, 2007 EPA Industry Meeting (PDF) (9 pp, 69K)