As the result of a joint rulemaking effort, the US Environmental Protection Agency’s (US EPA) Office of Transportation and Air Quality and the US Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) finalized new standards for medium- and heavy-duty vehicles and their engines on August 16, 2016. Included among the types of vehicles affected by these changes are vans, pickup trucks, tractors, trailers, semis, buses, and vocational vehicles with a gross vehicle weight rating of 8,500 lbs. or greater.

This new round of regulations, first proposed on June 19, 2015 and published for public comment on July 13, 2015, represents the second of two phases constituting a national program geared toward reducing greenhouse gas emissions and improving the fuel efficiency of medium- and heavy-duty vehicles. The final rules constituting Phase 1 of the national program, published on September 15, 2011, were presented as the “first-ever program to reduce greenhouse gas emissions and improve fuel efficiency of medium- and heavy-duty vehicles.” Vehicles built for the model years 2014-2018 were governed by the Phase 1 regulations, whereas Phase 2 focuses on model years 2018-2027 for certain trailers and model years 2021-2027 for semi-trucks, large pickup trucks, vans, and all buses and work trucks.

Phase 2 represents a combined effort by US EPA and NHTSA to advance fuel and emissions standards in accordance with President Obama’s February 18, 2014 directive on improving the fuel efficiency of American trucks. US EPA expects Phase 2 to reduce CO₂ emissions by approximately 1.1 billion metric tons and amount to savings of about $170 billion on fuel costs.  Oil consumption is expected to be reduced by up to 2 billion barrels over the lifetime of the vehicles covered by Phase 2.  In a departure from Phase 1, Phase 2 not only bases its standards on currently available technologies, but also contemplates technologies that are still emerging and not yet in widespread use.

In general, Phase 2 utilizes the same underlying regulatory structure as did Phase 1, including the separate engine standards and general categorization of medium- and heavy-duty vehicles. As did Phase 1, the new regulations adopt separate standards and test cycles for tractor engines, vocational diesel engines, and vocational gasoline engines.  These engine standards cover model years 2021-2027, with interim standards in model year 2024, for diesel engines.  Additionally, Phase 2 sets emissions and fuel efficiency standards for certain trailers used with heavy-duty combination tractors, which did not exist in the Phase 1 regulations.

Over 230,000 written comments were submitted on the proposed Phase 2 regulations. While many commenters expressed general support for the Phase 2 program, others called for no regulation or questioned the need for Phase 2 standards at all.  Additionally, some comments received addressed very specific details of the regulations.

This rulemaking affects a broad and diverse array of vehicles and engines.  Squire attorneys who participated in the public comment process for this rulemaking note that some vehicles will have a harder time meeting these new standards than others.  Manufacturers who face disproportionate burdens have legal options to seek reconsideration and/or judicial review if they act quickly.