MD/HD vehicles are typically grouped into seven classes based on gross vehicle weight rating (GVWR), and ranging from 8,501 to 10,000 pounds (Class 2b) to more than 33,001 pounds (Class 8). However, for the purposes of standard-setting, the agencies divided the industry into three discrete regulatory categories: combination tractors, heavy-duty pickups and vans, and vocational vehicles.
Combination Tractors (Classes 7 and 8)
The agencies created nine subcategories within the Class 7 and 8 combination tractor category based on the differences in expected emissions and fuel consumption associated with the key attributes of GVWR, cab type, and roof. To better performance, improvements are needed in aerodynamics and tires and reduction in idle operation as well as engine-based efficiency. Accordingly, two sets of standards have been issued. For vehicle-related emissions and fuel consumption, tractor manufacturers are required to meet vehicle-based standards. Compliance with the vehicle standard will typically be determined based on a customized vehicle simulation model, called the Greenhouse Gas Emissions Model (GEM). The model will be used to quantify the overall performance of the vehicle in terms of CO2 emissions and fuel consumption. In addition, the agencies are finalizing separate performance standards for engines manufactured for use in these trucks.
EPA’s standards include requirements to control leakage of leakage of HFC refrigerant from cabin air conditioning (A/C) systems from combination tractors, to apply to the tractor manufacturer.
Pickups and Vans (Classes 2B and 3)
The approach taken in developing standards for heavy-duty pickup trucks and vans is similar to that used for light-duty vehicles. Each manufacturer’s standard for a model year (MY) depends on its sales mix, with higher capacity vehicles (payload and towing) having numerically less stringent target levels, and with an added adjustment for 4-wheel drive vehicles.
About 90 percent of HD pickups and vans are 3/4-ton and 1-ton pickup trucks, 12- and 15-passenger vans, and large work vans sold by vehicle manufacturers as complete vehicles; no secondary manufacturer makes substantial modifications prior to registration and use. For these and related reasons, EPA says it believes it is appropriate to adopt GHG standards for HD pickups and vans based on the whole vehicle (including the engine), consistent with the way these vehicles are regulated by EPA today for criteria air pollutants. NHTSA believes it is appropriate to adopt corresponding gallons per 100 mile fuel consumption standards that are likewise based on the whole vehicle. Separate standards have been issued for diesel and gasoline heavy duty pickups and vans.
The standards take 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. Both agencies are providing manufacturers with two alternative phase-in approaches that get equivalent overall reductions. One alternative phases in the final standards at 15-20-40-60-100 percent in model years 2014-2015-2016-2017-2018. The other phases in the final standards at 15-20-67-67-67-100 percent in model years 2014-2015-2016-2017-2018-2019.
EPA’s standards include requirements to control leakage of hydrofluorocarbons (HFC) refrigerant from A/C systems for 2018 models in this category.
Vocational Vehicles (Class 2b-8)
The regulations for vocational vehicles are directed at companies that put together an incomplete vehicle — a chassis with an installed engine and an installed transmission. The vehicle is typically completed by other companies, generally small businesses that install other features, such as dump bed, delivery box, or utility bucket. As noted, the agencies believe it would be impractical to attempt to regulate these small businesses. Manufacturers will use GEM, the same customized vehicle simulation model used for Class 7 and 8 tractors, to determine compliance with the vocational vehicle standards.
The main manufacturer-generated input into the GEM for this category of trucks will be a measure of tire rolling resistance because tire improvements are the primary means available at this time to better the performance of vocational vehicles. Engine performance will also be an input into the model. The final standards vary based on the expected weight class and use of the truck into which the engine will be installed.
The vocational vehicle standards include provisions to account for and credit the use of hybrid technology, which can reduce emissions and fuel consumption. However specific fuel efficiency and GHG standards have not been developed for hybrids because EPA says it lacks the necessary test procedures, regulatory mechanisms, and baseline performance data.
Compliance with EPA’s GHG emission standards must begin with MY 2014. However, based on a statutory obligation, NHTSA must provide industry with four years of regulatory lead time. Therefore, the CAFE standards will be voluntary for MYs 2014 and 2015, becoming mandatory with MY 2016, except for diesel engine standards, which will be voluntary for MYs 2014, 2015, and 2016, becoming mandatory in MY 2017. If a manufacturer opts in to the NHTSA program, it must stay in the program for all the optional MYs.
The final GHG and CAFE standards for MD and HD engines and vehicles were published in the September 15, 2011, FR.