Highway Agency Defends Fuel Economy Calculations After Chevron

The National Highway Transportation and Safety Administration told a federal appeals court its longstanding methodology for calculating fuel-economy standards shouldn’t change in a post-Chevron era.

The agency filed a brief to the US Court of Appeals for the D.C. Circuit on Monday after the court ordered parties last month to explain how the Supreme Court’s decision in Loper Bright Enterprises v. Raimondo could apply to related suits challenging vehicle emissions standards.

The Natural Resources Defense Council asked the court to review NHTSA’s use of outside metrics for fuel efficiency standards in 2022, arguing the agency wasn’t setting high enough benchmarks—particularly ...