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United States adopt final GHG emissions and fuel efficiency standards for heavy-duty trucks

9 August 2011

The US Environmental Protection Agency (EPA) and the Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) adopted final regulations to reduce greenhouse gas (GHG) emissions and improve fuel efficiency of heavy-duty trucks. The standards apply to model year 2014-2018 medium- and heavy-duty vehicles, from semi trucks to the largest pickup trucks and vans, as well as all types and sizes of work trucks and buses in between.

For purposes of this program, the heavy-duty fleet incorporates all on-road vehicles rated at a gross vehicle weight (GVW) at or above 8,500 lbs, and the engines that power them, except those covered by the current GHG emissions and Corporate Average Fuel Economy standards for model year 2012-2016 passenger vehicles.

EPA and NHTSA have adopted standards for CO2 emissions and fuel consumption, respectively, for three main regulatory categories: (1) combination tractors, (2) heavy-duty pickup trucks and vans, and (3) vocational vehicles.

The stringency of the adopted standards is largely unchanged from the proposed rule, said EPA. In response to comments, technical changes were made to the emissions compliance model, which resulted in different numerical standards for combination tractors and vocational vehicles. Changes were also introduced to some testing and reporting requirements, to the averaging, banking and trading (ABT) provisions to make them more flexible, and provisions were added to encourage the development of advanced technologies and to simplify certification of engines and vehicles using innovative technologies.

In addition to the CO2 standards, EPA has adopted standards for N2O and CH4 emissions, that 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. The EPA has also adopted an HFC refrigerant leakage standard from air conditioning systems.

The standards for combination tractors and vocational vehicles include both engine and vehicle-based CO2 and fuel consumption limits. Compliance with the engine emission limits will be determined through engine dynamometer testing, while compliance with vehicle-based standards will typically be determined based on a customized vehicle simulation model, called the Greenhouse gas Emission Model (GEM), developed by EPA specifically for this regulation. Instead of using a chassis dynamometer as an indirect way to evaluate real-world operation and performance, various characteristics of the vehicle are measured and these measurements are used as inputs to the model. These characteristics relate to key technologies appropriate for this subcategory of truck—including aerodynamic features, weight reductions, tire rolling resistance, the presence of idle-reducing technology, and vehicle speed limiters.

The costs to the industry are small and will be more than offset by the expected fuel savings, according to the EPA. For example, the upgrades to a tractor trailer truck will cost $6,220 and will save an estimated $73,000 over the truck lifetime. For pickup trucks and vans the extra costs could be $1,050, and for vocational vehicles only $380.

The development of the program was conducted in cooperation with Environment Canada, who conducted truck emission testing at their facilities, under the Canada-US Air Quality Committee. Environment Canada is expected to adopt harmonized fuel economy and GHG emission standards for trucks.

The EPA and NHTSA said they 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 United States.

Source: US EPA