NHTSA Declares It Lacks Authority to Set Fuel-Economy Standards for Standalone Engines

NHTSA issued an interpretive rule concluding that it possesses legal authority to set fuel-economy standards only for medium- and heavy-duty vehicles, not for standalone engines. This reverses the position NHTSA has held since 2011. It lays the legal groundwork for eliminating the engine-level component of the jointly issued NHTSA/EPA Phase 1 (2011) and Phase 2 (2016) medium- and heavy-duty fuel efficiency program. Through its engine-level standards, NHTSA had been able to set fuel-economy standards not only for expressly covered vehicles, but also separately for engines used in combination tractors, vocational vehicles such as dumptrucks, and motorhomes.

NHTSA issued an interpretive rule concluding that it possesses legal authority to set fuel-economy standards only for medium- and heavy-duty vehicles, not for standalone engines. This reverses the position NHTSA has held since 2011. It lays the legal groundwork for eliminating the engine-level component of the jointly issued NHTSA/EPA Phase 1 (2011) and Phase 2 (2016) medium- and heavy-duty fuel efficiency program. Through its engine-level standards, NHTSA had been able to set fuel-economy standards not only for expressly covered vehicles, but also separately for engines used in combination tractors, vocational vehicles such as dumptrucks, and motorhomes.