Medium- and heavy-duty vehicles currently account for about 20% of GHG emissions and oil use in the US transportation sector, but only comprise about five percent of vehicles on the road. Globally, oil consumption and GHG emissions from heavy-duty vehicles are expected to surpass that of passenger vehicles by 2030. Through the G-20 and discussions with other countries, the United States is working with other major economies to encourage progress on fuel economy standards in other countries.

The proposed standards are expected to lower CO₂ emissions by approximately 1 billion metric tons, cut fuel costs by about $170 billion, and reduce oil consumption by up to 1.8 billion barrels over the lifetime of the vehicles sold under the program. These reductions are nearly equal to the greenhouse gas (GHG) emissions associated with energy use by all US residences in one year. The total oil savings under the program would be greater than a year’s worth of US imports from the Organization of the Petroleum Exporting Countries (OPEC) each year, the agencies calculated.

The proposed standards do not mandate the use of specific technologies. Rather, they establish standards achievable through a range of technology options, and allow manufacturers to choose those technologies that work best for their products and for their customers

The proposed rule (1,329 pages) includes averaging, banking, and trading (ABT) compliance provisions for the engine and vehicle standards. These provisions would allow manufactures to trade credits, bank credits for future years, and average credits, which allows manufacturers to certify engines or vehicles that do not perform up to the standard and offset them with engines or vehicles that perform better than the standard.

This ABT program was established under Phase 1, and EPA and NHTSA are proposing to continue it with some minor revisions. The ABT flexibilities are designed to help increase the rate at which new technologies could be implemented, reduce the cost of compliance, and address potential lead time challenges in meeting the standards.

Proposed CO₂ and Fuel Consumption Standards. The agencies are proposing new, more stringent standards for the same classes of heavy-duty vehicles currently regulated through model 2018 and beyond under Phase 1. They are also proposing the first CO₂ and fuel efficiency standards for certain trailers used with heavy-duty combination tractors.

EPA’s proposed CO₂ emissions standards and NHTSA’s proposed fuel consumption standards are tailored to each of four regulatory categories of heavy-duty vehicles. The proposal also includes separate standards for the engines that power combination tractors and vocational vehicles.

1. Combination Tractors. Class 7 and 8 combination tractors and their engines account for roughly two thirds of total GHG emissions and fuel consumption from the heavy-duty sector due to their large payloads and high number of vehicle miles traveled (VMT).

   The proposed CO₂ and fuel consumption standards for combination tractors and engines would start in model year (MY) 2021, increase incrementally in MY 2024, and phase in completely by MY 2027. The proposed standards differ by vehicle weight class, roof height, and cab type (sleeper or day).

   The fully phased-in standards would achieve up to 24% lower CO₂ emissions and fuel consumption compared to the Phase 1 standards. The proposed tractor standards could be met through improvements in the engine, transmission, driveline, aerodynamic design, lower rolling resistance tires, extended idle reduction technologies, and other accessories of the tractor.

2. Trailers Pulled by Combination Tractors. The proposed standards would apply to certain trailer types beginning in MY 2018 for EPA’s standards, and would be voluntary for NHTSA from 2018 to 2020, with mandatory standard beginning in 2021. The proposed standards would extend to more trailer types in MY 2021.

   The fully-phased standards would apply to 5 categories of trailers: long (longer than 50 feet) highway box trailers-dry vans; long highway box trailers - refrigerated vans; short (50 feet and shorter) highway box trailers - dry vans; short highway box trailers -refrigerated vans; and non-box highway trailers.

   The standards increase in stringency in MYs 2021 and 2024, with final standards in MY 2027. Some types of trailers would have reduced requirements or would be excluded from the trailer standards altogether, including those designed for logging and mining, as well as mobile homes.

   The fully phased-in trailer standards would achieve up to 8% lower CO₂ emissions and fuel consumption compared to an average MY 2017 trailer. Technologies that could be used to meet the proposed standards include: aerodynamic devices, lower rolling resistance tires, automatic tire inflation systems, and weight reduction.

3. Heavy-duty Pickup Trucks and Vans. Heavy- and medium-duty pickup trucks and vans represent about 15% of the fuel consumption and GHG emissions from the heavy- and medium-duty vehicle sector. The agencies are proposing new CO₂ emission and fuel consumption standards for heavy-duty pickups and vans that would be applied in largely the same manner as the Phase 1 standards.

   Under this approach, all manufacturers face the same standards, but the average emission and fuel consumption rates applicable to each manufacturer depend on the manufacturer’s sales mix, with higher capacity vehicles (payload and towing) having less stringent targets. The proposed standards for this segment take the form of a set of target standard curves, based on a “work factor” that, as in Phase 1, combines a vehicle’s payload, towing capabilities, and whether or not it has 4-wheel drive. The proposed standards would become 2.5% more stringent every year from model years 2021 to 2027.

   The proposed program would reduce CO₂ emissions and fuel consumption for these vehicles by about 16% beyond Phase 1 when fully phased in. Under Phase 2, the agencies expect newer, advanced technologies such as engine stop start and powertrain hybridization will also become available in this segment of the market. These newer technologies are not mandated but some manufacturers may choose to use them to meet the standard.

4. Vocational Vehicles. Vocational vehicles consist of a wide variety of truck and bus types, including delivery trucks, refuse haulers, public utility trucks, transit, shuttle, and school buses. This segment also includes very specialized vehicles such as emergency vehicles, and cement and dump trucks. Vocational vehicles represent about one fifth of the total medium- and heavy-duty fuel consumption.

   The agencies are proposing new CO₂ and fuel consumption standards for vocational vehicles starting in MY 2021, with increased stringency in MY 2024, and a fully phased-in stringency level in MY 2027. The proposed vocational vehicle standards are differentiated using three vehicle weights and three driving cycles. The agencies are also proposing separate standards for emergency vehicles.

   The fully phased-in standards would achieve up to 16% reduction in CO₂ emissions and fuel consumption relative to Phase 1. The agencies project that the proposed vocational vehicle standards could be met through improvements in the engine, transmission, driveline, lower rolling resistance tires, workday idle reduction technologies, and weight reduction.

5. Engine standards. As with the Phase 1 program, the agencies are proposing separate standards and test cycles for tractor engines, vocational diesel engines, and vocational gasoline engines.

   For diesel engines, the proposed standards would begin in model year 2021 and phase in to MY 2027, with interim standards in MY 2024. The agencies are also proposing a revised test cycle weighting for tractor engines to better reflect actual in-use operation.

   The proposed diesel engine standards would reduce CO₂ emissions and fuel consumption by up to 4% compared to Phase 1. Technologies that could be used to meet the standards include: combustion optimization; improved air handling; reduced friction within the engine; improved emissions after-treatment technologies; and waste heat recovery.

Because certain refrigerants are also extremely potent GHGs, the program includes EPA- proposed standards to control leakage of hydrofluorocarbons (HFCs) from air conditioning systems in vocational vehicles. Similar HFC standards already apply under the Phase 1 program for combination tractors, and for pickup trucks and vans. EPA is also proposing more stringent nitrous oxide (N₂O) standards for heavy-duty engines.

The proposed standards are fully harmonized between NHTSA and EPA. The agencies have worked closely with the State of California’s Air Resources Board (ARB) in developing the proposed standards. All three agencies are committed to the goal of setting a single set of national standards. Throughout every stage of development, the Administration’s fuel efficiency program has benefited from close partnership with industry, labor and environmental leaders. With this proposal, a high level of engagement with stakeholders will continue to be critical, as feedback will be instrumental to the agencies’ work to finalize the standards by 2016.

A public comment period will be open for 60 days after the proposal is published in the Federal Register. In addition, NHTSA and EPA will host two public hearings and continue our open-door policy of meeting with stakeholders over the course of the comment period.

In addition to the proposed standards, EPA and NHTSA are seeking comment on alternative standards that would accelerate the program by 2-3 years as well as several other alternative sets of standards, including less stringent and more stringent options.

Resources

• Notice of Proposed Rulemaking)