NHTSA Interpretive Rule Asserts Authority to Reset CAFE Standards

NHTSA published an interpretive rule claiming that the Biden Administration ignored statutory requirements in establishing CAFE standards, providing NHTSA with the authority to revise these standards. NHTSA also claimed related authority to revise the commercial medium- and heavy-duty on-highway vehicle and work truck fuel efficiency improvement program.

NHTSA’s interpretation argues that, under 49 U.S.C. 329023, when carrying out its statutory directive to set fuel economy standards at the maximum feasible level, “NHTSA must not consider the fuel economy of dedicated automobiles; must consider dual-fueled automobiles to be operated only on gasoline or diesel fuel; and must not consider, when prescribing a fuel  economy standard, the trading, transferring, or availability of credits.” NHTSA further asserts that it cannot, “in any respect and at any point in the process,” consider designated vehicles when setting fuel economy standards, and that the Biden Administration’s accounting for California’s and other states’ Zero-Emission Vehicle mandates violated this policy, by “increasing the level of standards that could be considered maximum feasible.”

This interpretive rule does not by itself change existing CAFE or medium- and heavy-duty standards. However, NHTSA stated that, during the rulemaking process for replacement standards, it will “exercise its enforcement authority regarding all existing CAFE and medium- and heavy-duty standards in accordance with the interpretation set forth in this rulemaking.”