California Spearheads 26-State Lawsuit Challenging Trump Administration Fuel Efficiency Rollback

Two lawsuits were filed on Friday challenging a Trump administration decision to cut fuel efficiency standards. Twenty-six states, including California and New York, initiated legal action against United States President Donald Trump’s administration after the US Department of Transportation lowered fuel economy standards for petrol-powered vehicles.

The lawsuit targets the Department of Transportation’s rollback of fuel economy standards to a fleet average fuel economy of 34.9 miles (56km) per gallon (3.78 litres) by model year 2031. Under the administration of former President Joe Biden, these standards were previously set at 50.4 miles (81km) per gallon by model year 2031.

California Attorney General Rob Bonta, who is leading the litigation, argued that the Trump administration improperly changed how federal regulators calculate fuel economy standards. The National Highway Traffic Safety Administration (NHTSA) bases standards on technological improvements that could make petrol-powered vehicles more efficient by modeling current fleet performance and evaluating additional manufacturer actions.

Bonta stated that the Transportation Department's methodology change ignores existing electric vehicles, making it easier to justify weaker standards for petrol-powered vehicles, and labeled the approach as "flawed" and "dramatically distorted." The lawsuit further alleges that the new rule is contrary to law and violates Congress's mandate to set fuel-economy standards at their "maximum feasible" level.

While the Transportation Department argued the change could save American taxpayers $138bn over the next five years, Attorney General Bonta strongly criticized the move, stating it forces Americans to spend billions more on gas while harming community air quality. Conversely, the rollback received support from automakers, with Shane Karr of Stellantis North America welcoming the reset to more achievable targets.

In tandem with the states' legal action, a second lawsuit was filed on Friday by progressive and climate groups, including the Environmental Defense Fund and Public Citizen. Robert Weissman of Public Citizen condemned the rollback as lawless and harmful to air quality. Meanwhile, auto stocks trended downward, with Ford, General Motors, and Toyota closing down around 1 percent, while Stellantis fell more than 6 percent amid slumping sales reports.