California and a coalition of 26 states, cities, and counties filed a federal lawsuit Friday to challenge a National Highway Traffic Safety Administration rule that weakens corporate average fuel economy standards for passenger cars and light trucks, cutting projected fleet efficiency targets for 2031.
The Trump administration’s rollback lowers the fuel-economy requirement for 2031 model-year vehicles to 34.9 miles per gallon, far below the 50.4 miles per gallon target set under the Biden administration, or 52.5 miles per gallon according to Transportation Department figures cited in separate filings. The legal challenge was filed in the U.S. Court of Appeals for the First Circuit in Massachusetts.
Federal officials argue the adjustment supports domestic automakers and lowers vehicle acquisition costs for consumers. State attorneys general and environmental organizations counter that the standard violates the Energy Policy and Conservation Act of 1975 by failing to meet congressional mandates for maximum feasible efficiency.
Fuel Targets Drop as Consumer Costs Rise
The rollback lowers requirements across the next five years below the efficiency levels the national automotive fleet actually achieved in 2021. This weaker standard will force the average driver of a new car to spend more than $1,600 more on gasoline over the lifetime of the vehicle.
Transportation Department estimates indicate the regulation reduces manufacturing compliance costs by an average of $1,289 per vehicle. However, it increases total U.S. gasoline consumption through 2050 by 4.6%, or roughly 121 billion gallons, compared to prior rules.
“Joe Biden and Pete Buttigieg illegally twisted mileage standards to create an electric vehicle mandate — jacking up car prices for American families and forcing manufacturers to produce vehicles no one wanted. I’m proud to stand with President Trump to say that those days are over.”
Sean Duffy, U.S. Transportation Secretary, via Los Angeles Times
States Claim NHTSA Ignored Existing Electric Vehicles
California Attorney General Rob Bonta and Michigan Attorney General Dana Nessel lead a multi-state coalition asserting that NHTSA mismanaged its statutory authority under the Energy Policy and Conservation Act enacted by Congress in 1975. The lawsuit contends the administration ignored millions of electric vehicles already on American roadways when establishing its baseline, distorting the analysis of what technological improvements are economically and practically feasible.
“The President started a war that has created volatility in oil markets, disrupted global energy supplies, and left families and businesses paying the price at the pump. Yet, the Trump Administration is attempting to gut fuel economy standards and force Americans to spend billions more on gas while poisoning the air in our communities.”
Rob Bonta, California Attorney General, via State of California Department of Justice
State officials highlighted surging pump prices. In California, gasoline averaged $6.40 a gallon on Friday, compared with $4.65 a gallon one year prior, according to AAA data.
Regulations End Credit Trading for EV Makers
The revised federal regulations terminate the CAFE credit trading program in 2028. This mechanism allowed electric vehicle manufacturers such as Tesla, Rivian, and Lucid to generate substantial revenue by selling compliance credits to legacy automakers.
Traditional manufacturers supported the reset. Stellantis officials stated the company welcomes efforts to align fuel economy rules with existing market realities.
“The government should be encouraging automotive innovation that our workers, manufacturers and communities have helped drive for generations. This new rule leaves Michigan families more exposed than ever to the swings of global oil prices and I stand firmly with my colleagues in telling NHTSA it’s time to follow the Congressional mandate.”
Dana Nessel, Michigan Attorney General, via The Detroit News
Chicago Mayor Brandon Johnson confirmed his city’s participation in the coalition led by California.