Environmental Groups Sue Trump Administration Over Eased Fuel Economy Rules

A coalition of environmental organizations filed a lawsuit Friday against the Trump administration, challenging its recent decision to relax key vehicle fuel economy standards. The groups argue that the relaxed rules will result in less efficient vehicles, increased pollution, and higher gasoline consumption.

The lawsuit, filed in the U.S. Court of Appeals, names Transportation Secretary Sean Duffy and National Highway Traffic Safety Administration (NHTSA) Administrator Jonathan Morrison as defendants. The organizations involved include the Sierra Club, the Center for Biological Diversity, the Conservation Law Foundation, the Environmental Defense Fund, and Public Citizen.

Katherine Garcia, director of Sierra Club’s Clean Transportation for All program, stated that the administration is "turning back the clock on fuel-efficient cars," forcing drivers to spend more on gas and exposing communities to toxic air. She characterized the rollback as a prioritization of "Big Oil and automaker profits over American families."

The Transportation Department and NHTSA officially lowered the Corporate Average Fuel Economy (CAFE) standards earlier in the week. The new regulations set a fleetwide average of approximately 34.9 miles per gallon for passenger cars and light trucks by the 2031 model year. This represents a significant decrease from the projected 50.4 miles per gallon under previous rules established by the Biden administration.

Administration officials have defended the change, asserting it will offer consumers more vehicle choices and encourage the purchase of newer, safer vehicles. Secretary Duffy stated the new rule removes an "illegal mandate" that pushed automakers to produce expensive electric vehicles that he claimed American families did not want. However, experts note that reducing fuel economy requirements does not necessarily lower vehicle costs or guarantee increased new vehicle sales, and that there has been no mandate forcing manufacturers to sell or consumers to buy electric vehicles.

Auto companies and industry groups have generally welcomed the regulatory change, deeming the previous standards too stringent. However, environmental advocates have sharply criticized the move.

"With gas prices at historic highs, Trump picked the worst possible time to roll back federal mileage standards," said David Pettit, an attorney at the Center for Biological Diversity’s Climate Law Institute. He added that while oil companies stand to profit, drivers will face financial burdens and children will breathe dirtier air due to increased tailpipe pollutants.

The lawsuit comes amid elevated energy prices, with gasoline prices averaging around $4.50 per gallon and diesel reaching unprecedented levels recently, according to AAA. The Department of Transportation projected that the rule change would cut yearly oil consumption by about 1.3 billion barrels by 2050 compared to 2024 levels. In contrast, NHTSA had previously estimated that the 2024 standards would have saved 14 billion gallons of gasoline from being burned by that year.

Fuel economy requirements have been a feature of U.S. vehicle regulations since the energy crisis of the 1970s, contributing to improvements in average vehicle efficiency over time. The Trump administration has previously taken several actions impacting cleaner vehicle initiatives, including the elimination of electric vehicle tax credits, the scrapping of vehicle emissions standards, and the repeal of fines for automakers failing to meet mileage rules.