Final rule · 2025-10586

Resetting the Corporate Average Fuel Economy Program

The National Highway Traffic Safety Administration is issuing this interpretive rule to set forth the agency's interpretation of the factors the agency is prohibited by law from considering when setting maximum feasible fuel economy standards under the Energy Policy and Conservation Act of 1975, the Energy Independence and Security Act of 2007, and other applicable law. This rule describes NHTSA's interpretation of its authority to establish the necessary legal foundation for bringing the Corporate Average Fuel Economy (CAFE) program into compliance with relevant statutory requirements. The rule also describes NHTSA's interpretation of its authority for a commercial medium- and heavy-duty (MDHD) on-highway vehicle and work truck fuel efficiency improvement program, also establishing the necessary legal foundation for bringing that program into compliance with the law. Pending the rulemaking process for the establishment of replacement standards, NHTSA will exercise its enforcement authority with regard to all existing CAFE and MDHD standards in accordance with the interpretation set forth in this rule.