Heavy-duty vehicles include both work trucks and commercial medium and heavy-duty on-highway vehicles as defined by the Energy Independence and Security Act (EISA). Heavy-duty engines affected by the final standards are generally those that are installed in commercial medium- and heavy-duty trucks and buses. The agencies’ scopes are the same except that EPA is including recreational on-highway vehicles (RVs, or motor homes) within its rulemaking, while NHTSA is not including these vehicles.

Under the new program, trucks and buses built in 2014 through 2018 will reduce oil consumption by a projected 530 million barrels and greenhouse gas (GHG) pollution by approximately 270 million metric tons. The joint DOT/EPA program will include a range of targets which are specific to the diverse vehicle types and purposes. Vehicles are divided into three major categories:

• combination tractors (semi-trucks);
• heavy-duty pickup trucks and vans; and
• vocational vehicles such as transit buses and refuse trucks.

The joint standards cover not only engines but also complete vehicles, allowing the agencies to achieve the greatest possible reductions in fuel consumption and GHG emissions, while avoiding unintended consequences.

To account for this in the regulatory program, two types of standard metrics have been adopted: payload-dependent gram per mile (and gallon per 100- mile) standards for pickups and vans; and gram per ton-mile (and gallon per 1,000 ton-mile) standards for vocational vehicles and combination tractors. These metrics account for the fact that the work to move heavier loads burns more fuel, and emits more CO₂ than in moving lighter loads.

Within each of the three categories of trucks, even more specific targets are laid out based on the design and purpose of the vehicle—e.g., a semi truck with a low roof versus a semi truck with a high roof. Fuel efficiency improvement goals are then charted for each year and for each vehicle category and type.

By the 2018 model year, the program is expected to achieve significant savings relative to current levels, across vehicle types.

• Combination Tractors. Heavy-duty combination tractors—the semi trucks that typically pull trailers—are built to move freight. Freight transportation customers choose tractors primarily based on two major characteristics: the gross vehicle weight rating (GVWR, which establishes the maximum carrying capacity of the tractor and trailer) and cab type (sleeper cabs provide overnight accommodations for drivers). Operators also consider the tractor roof height when mating with trailers for the most efficient configuration.

  The agencies have adopted differentiated standards for nine subcategories 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 Table 1. These final standards will achieve from 9–23% reduction in emissions and fuel consumption from affected tractors over the 2010 baselines.

• Heavy-Duty Pickup Trucks and Vans. The agencies are setting corporate average standards for heavy-duty pickup trucks and vans, similar to the approach taken for light-duty vehicles. Each manufacturer’s standard for a model year 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. This approach recognizes both the inherently higher GHG emissions and fuel consumption of higher-capacity vehicles, and the importance of payload and towing capacity to the owners of these work trucks and vans.

  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% for diesel vehicles and 12% for gasoline vehicles, compared to a common baseline.

  NHTSA is setting corporate average standards for fuel consumption that are equivalent to EPA’s standards (though not including EPA’s final air conditioning leakage standard). The final NHTSA standards represent an average per-vehicle improvement in fuel consumption of 15% for diesel vehicles and 10% for gasoline vehicles, compared to a common baseline.

  To satisfy lead time requirements under EISA, 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 manufacturers, 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 Table 2 represent emission reductions from 6–9%, from a 2010 baseline.

Click to enlarge.

In addition to the CO₂ standards described above, EPA has adopted standards for N₂O and CH₄ emissions. N₂O and CH₄ are important GHGs that contribute to global warming, more so than CO₂ for the same amount of emissions. While today’s gasoline and diesel engines emit relatively low levels of N₂O and CH₄ emissions, EPA’s standards will act to cap emissions to ensure that manufacturers do not allow the N₂O and CH₄ emissions of their future engines to increase significantly above the currently controlled low levels.

Air conditioning (A/C) systems contribute directly to GHG emissions through leakage of HFC refrigerants, which are powerful GHG pollutants. EPA has adopted standards to assure that high-quality, low-leakage components are used in each air conditioning system designed for heavy-duty pickup trucks and vans, and semi trucks. The standard for larger A/C systems (capacity above 733 grams) is measured in percent total refrigerant leakage per year, while the standard for smaller A/C systems (capacity of 733 grams or less) is measured in grams of refrigerant leakage per year.

While the first two years of the NHTSA standards will be voluntary, vehicle manufacturers will be required to meet the corresponding EPA standards for those two years. Small businesses are excluded from both the EPA and DOT standards.

Flexibilities. EPA’s and NHTSA’s final HD National Program provides flexibilities to manufacturers in terms of how they can comply with the new standards. These flexibilities are expected to provide sufficient lead time for manufacturers to make necessary technological improvements and reduce the overall cost of the program, without compromising overall environmental and fuel consumption objectives.

The primary flexibility provisions are an engine averaging, banking, and trading (ABT) program and a vehicle ABT program. These ABT programs will allow for emission and fuel consumption credits to be averaged, banked, or traded within each of the defined averaging sets.

There are three weight-based averaging sets for two of the regulatory categories: combination tractors and vocational vehicles. The pickup trucks and vans are one fleetwide averaging set, and there are four averaging sets for engines.

In addition to the general ABT programs, EPA is providing engine manufacturers and heavy-duty pickup and van manufacturers the added option of using CO₂ credits to offset CH₄ or N₂O emissions that exceed the applicable emission standards based on the relative global warming potentials of these emissions.

The structure of the ABT program for HD engines is based closely on earlier EPA ABT programs for HD engines; the program for pickup trucks and vans is built on the existing light-duty GHG and fuel economy credit carry-forward, carry-back, and trading provisions; and first-time ABT provisions are adopted for other HD vehicle manufacturers that are as consistent as possible with the provisions for other categories.

The agencies have adopted three additional optional credit opportunities:

• An early credit option intended for manufacturers who demonstrate improvements in excess of the standards prior to the model year that they become effective;

• a credit program intended to promote implementation of advanced technologies, such as hybrid powertrains, engines with Rankine cycle waste heat recovery systems, and electric or fuel cell vehicles; and

• a credit intended to apply to new and innovative technologies that reduce vehicle CO₂ emissions and fuel consumption, for which the benefits are not captured over the test procedure used to determine compliance with the standards (i.e., “off-cycle”).

Administration analysis projects that the standards will yield an estimated $50 billion in net benefits over the life of model year 2014 to 2018 vehicles, and to result in significant long-terms savings for vehicle owners and operators. A semi-truck operator could pay for the technology upgrades in less than a year and realize net savings of $73,000 through reduced fuel costs over the truck’s useful life. These cost saving standards will also reduce emissions of harmful air pollutants like particulate matter, which can lead to asthma, heart attacks and premature death.

The agencies are considering a next phase of rules for this sector, as there are more opportunities to reduce GHG emissions and fuel use from the heavy-duty fleet for model years beyond 2018. The goals would include spurring innovation as well as updating the assessment of actual emissions and fuel use from this sector. Such future regulation would also be designed to align with similar programs developed outside the US.

Resources

• Heavy Duty regulations

• Final Rulemaking to Establish Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles: Regulatory Impact Analysis