Fuel Consumption credit (deficit)(gallons) = (Std-FEL) × (Payload Tons) × (Volume) × (UL) × 103,

where:

Std = Standard associated with the regulatory category (gallons/1,000 ton-mile) (fuel consumption: Gallons/1,000 ton-mile)

Payload tons = Prescribed payload for each subcategory (12.5 tons for Class 7 tractors, 19 tons for Class 8 tractors, 2.85 tons for light heavy-duty [LHD] vocational, 5.6 tons for medium heavy-duty [MHD] vocational, 7.5 tons for heavy heavy-duty [HHD] vocational vehicles)

FEL = Family emission or fuel-consumption limit for the vehicle family (gallons/1,000 ton miles)

Volume = (Projected or actual) production volume of the vehicle family

UL = Useful life of the vehicle (435,000 miles for HHD, 185,000 miles for MHD, and 110,000 miles for LHD)

Early Credits

The final rules include an option for a manufacturer to obtain early credits by certifying a subcategory of vehicles at fuel-consumption levels below the standard prior to the model year the standard becomes effective. A 1.5 multiplier will be applied to early credits earned in model year 2013. Early credits provide an incentive for manufacturers to introduce more efficient engines and vehicles earlier than required by the standards.

Advanced Technology Credits

The final rules include a provision for obtaining credits for introducing advanced technologies to provide an incentive for their introduction. A 1.5 multiplier will be applied to these credits, but the total credits are capped in any model year. Hybrid powertrain designs that include energy storage systems are one of the advanced technologies defined by the agencies.

REFERENCES

EPA/NHTSA (Environmental Protection Agency [Office of Transportation and Air Quality]/National Highway Traffic Safety Administration [Department of Transportation]). 2010a. Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles. Dockets No. EPA-HQ-OAR-2010-0162 and No. NHTSA-2010-0079, October 25, 2010. Available at http://www.regulations.gov.

EPA/NHTSA. 2010b. Draft Regulatory Impact Analysis, Proposed Rulemaking to Establish Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles. EPA-420-D-10-901. October.

EPA/NHTSA. 2011a. Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles, Final Rules. August 9.

EPA/NHTSA. 2011b. Final Rulemaking to Establish Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles, Regulatory Impact Analysis. EPA- 420-R-11-901. August.



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