California Leads Lawsuit Against NHTSA Over Weakened Fuel Rules
California Attorney General Rob Bonta on October 2, 2026, led a coalition of 26 states, counties, and cities in filing a lawsuit against the National Highway Traffic Safety Administration (NHTSA) to challenge its final rule weakening corporate average fuel economy (CAFE) standards for new passenger cars and light trucks. The lawsuit, filed in the U.S. Court of Appeals for the First Circuit, alleges that NHTSA violated its statutory mandate to set fuel-economy standards at their maximum feasible
level, as required by Congress.
The rule, which reduces the fuel-economy requirement for 2031 model-year vehicles to 34.9 miles per gallon—down from 50.4 mpg under the Biden administration—has been criticized for undermining consumer savings and environmental protections. California and its allies argue that NHTSA’s approach wildly distorts the starting point
for its analysis by excluding existing electric vehicles (EVs) from the baseline used to determine future efficiency targets. This, they claim, results in dramatically weaker standards
that fail to reflect the technological advancements already in use.
Legal Disputes and Broader Impacts
The final rule also ends the CAFE credit trading program by 2028, which has provided revenue to EV manufacturers like Tesla and Rivian. California highlighted that the U.S. fleet achieved higher efficiency in 2021 than the standards set by the new rule, calling it a “backsliding” move. The lawsuit marks California’s 97th legal challenge against the Trump administration in 88 weeks, underscoring the state’s ongoing efforts to counter policies it deems harmful to public health and the environment.
NHTSA officials did not immediately respond to requests for comment, though the agency previously defended the rule as a measure to boost the domestic auto industry and lower consumer costs. The case now awaits judicial review, with implications for federal vehicle regulations and the future of EV incentives.
Byline: priyanka.patel tech editor