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Greenhouse Gas and Fuel Effiency Standards for Trucks and Buses

Most Recent Action

Final rules were published in the Federal Register on September 15, 2011.



The Environmental Protection Agency (EPA) and the Department of Transportation’s (DOT) National Highway Traffic Safety Administration (NHTSA) are proposing new standards for three categories of heavy trucks: combination tractors, heavy-duty pickups and vans, and vocational vehicles. The categories were established to address specific challenges for manufacturers in each area.

The EPA is adopting GHG emissions standards under the Clean Air Act, and NHTSA is adopting fuel efficiency standards under EISA.

The EPA and the NHTSA are referring to the proposed rules as the “HD National Program.”



President Obama issued a Presidential Memorandum on May 21, 2010, directing the EPA and the NHTSA to work on a joint rulemaking under the Clean Air Act (CAA) and the Energy Independence and Security Act of 2007 (EISA) to establish greenhouse gas emissions and fuel efficiency standards for commercial medium- and heavy-duty vehicles.



The agencies have each adopted complementary standards under their respective authorities covering model years 2014-2018, which together form a comprehensive HD National Program. EPA and NHTSA have adopted standards for CO2 emissions and fuel consumption, respectively, tailored to each of three main regulatory categories: (1) combination tractors; (2) heavy-duty pickup trucks and vans; and (3) vocational vehicles.

Combination Tractors

Heavy-duty combination tractors – the semi trucks that typically pull trailers – are built to move freight. The agencies have adopted differentiated standards for nine sub-categories of combination tractors based on three attributes: weight class, cab type and roof height. The standards will phase in to the 2017 levels shown in the table below. These final standards will achieve from nine to 23 percent reduction in emissions and fuel consumption from affected tractors over the 2010 baselines.

The agencies’ scopes are the same except that EPA is including recreational on-highway vehicles (RV’s, or motor homes) within its rulemaking, while NHTSA is not including these vehicles. The EPA has additionally adopted standards to control HFC leakage from air conditioning systems in pickups and vans and combination tractors. Also exclusive to the EPA program are EPA’s N2O and CH4 standards that will apply to all heavy-duty engines, pickups and vans. Trailers are not included in this rulemaking, but will be addressed in the future.

The EPA and NHTSA estimate that the HD National Program will cost the affected industry about $8 billion, while saving vehicle owners fuel costs of about $50 billion over the lifetimes of model year 2014-2018 vehicles, discounted at three percent.

EPA Emissions Standards (g CO2/ton-mile)

NHTSA Fuel Consumption Standards (gal/1,000 ton-mile)

Low Roof Mid Roof High Roof Low Roof Mid Roof High Roof
Day Cab Class 7 104 115 120 10.2 11.3 11.8
Day Cab Class 8 80 86 89 7.8 8.4 8.7
Sleeper Cab Class 8 66 73 72 6.5 7.2 7.1


Heavy-Duty Pickup Trucks and Vans

The EPA has established standards for this segment in the form of a set of target standard curves, based on a “work factor” that combines a vehicle’s payload, towing capabilities, and whether or not it has 4-wheel drive. The standards will phase in with increasing stringency in each model year from 2014 to 2018. The EPA standards adopted for 2018 (including a separate standard to control air conditioning system leakage) represent an average per-vehicle reduction in GHG emissions of 17 percent for diesel vehicles and 12 percent for gasoline vehicles, compared to a common baseline.

The NHTSA is setting corporate average standards for fuel consumption that are equivalent to the EPA‘s standards. The final NHTSA standards represent an average per-vehicle improvement in fuel consumption of 15 percent for diesel vehicles and 10 percent for gasoline vehicles, compared to a common baseline. To satisfy lead time requirements under EISA, the NHTSA standards will be voluntary in 2014 and 2015. Both agencies are providing manufacturers with two alternative phase-in approaches that get equivalent overall reductions. One alternative phases the final standards in at 15-20-40-60-100 percent in model years 2014-2015-2016-2017-2018. The other phases the final standards in at 15-20-67-67-67-100 percent in model years 2014-2015-2016-2017-2018-2019.

Vocational Vehicles

Vocational vehicles consist of a very wide variety of truck and bus types including delivery, refuse, utility, dump, cement, transit bus, shuttle bus, school bus, emergency vehicles, motor homes, tow trucks, and many more. Vocational vehicles undergo a complex build process, with an incomplete chassis often built with an engine and transmission purchased from different manu-facturers, which is then sold to a body manufacturer. In these rules, the agencies are regulating chassis manufacturers for this segment. The agencies have divided this segment into three regulatory subcategories – Light Heavy (Class 2b through 5), Medium Heavy (Class 6 and 7), and Heavy Heavy (Class 8), which is consistent with the engine classification.

After engines, tires are the second largest contributor to energy losses of vocational vehicles. The final program for vocational vehicles for this phase of regulatory standards is limited to tire technologies (along with the separate engine standards). The standards depicted in the table below represent emission reductions from six to nine percent, from a 2010 baseline.

EPA Full Useful Life Emissions Standards (g CO2/ton-mile)

NHTSA Fuel Consumption Standards (gal/1,000 ton-mile)

Light Heavy Class 2b-5 373 36.7
Medium Heavy Class 6-7 225 22.1
Heavy Heavy Class 8 222 21.8



Related Documents

Final Rulemaking: Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles, September 15, 2011

Fact Sheet: EPA and NHTSA Adopt First-Ever Program to Reduce Greenhouse Gas Emissions and Improve Fuel Efficiency of Medium- and Heavy-Duty Engines and Vehicles (PDF), August 2011

Fact Sheet: Paving the Way Toward Cleaner, More Efficient Trucks (PDF), August 2011

Final Regulatory Impact Analysis (RIA) (PDF), August 2011

Heavy-Duty Vehicle Greenhouse Gas Emissions Inventory for Air Quality Modeling Technical Support Document (PDF), August 2011

Air Quality Modeling Technical Support Document: Heavy-Duty Vehicle Greenhouse Gas Emission Standards Final Rule (PDF), August 2011

Correction Notice: Preamble and Regulations; December 29, 2010

Preamble and Regulations; November 30, 2010

Fact Sheet; October 2010

Draft Regulatory Impact Analysis; October 2010