26 States and Three Cities Sue to Block Trump's Cut in Fuel Economy Standards

Twenty-six states, the District of Columbia and the cities of New York, Chicago and Denver sued the Trump administration on Friday to stop a rule that sharply lowers federal fuel economy standards for new cars and trucks.

The lawsuit, led by California, challenges a final rule from the Department of Transportation that sets a fleet-wide fuel economy requirement of 34.9 miles per gallon by model year 2031. The standard adopted under President Joe Biden would have required 50.4 miles per gallon by the same year. Other states in the suit include Arizona, Colorado, Connecticut, Massachusetts, Michigan, New Jersey and Washington.

California Attorney General Rob Bonta argues the rule breaks the law. Federal statute directs the National Highway Traffic Safety Administration to set standards at the "maximum feasible" level, and the states say the agency picked a number that is far below it. They also say the agency's analysis "tries to paper over nearly $220 billion in lost fuel savings" for drivers.

The Transportation Department's own estimates, cited in the complaint, show that the weaker standards will lower the price of new vehicles but increase gasoline use and carbon dioxide emissions for decades. The agency has defended the rollback as a way to make cars cheaper and give automakers more room to sell the vehicles buyers want. Industry groups have lobbied for looser rules, saying the Biden-era targets were out of step with what shoppers are buying.

The suit is one more fight over vehicle rules between California and Washington. The state has long set its own tailpipe standards under a Clean Air Act waiver, and the administration has moved against that authority too. A fuel economy fight matters because the federal rule sets the floor for the whole national market. A weaker floor makes it easier for automakers to sell less efficient vehicles everywhere, including in states that want cleaner cars.

The case will be heard in a federal appeals court, and a ruling could take months or longer. In the meantime the new standards stand unless a court stays them, and the states have not said whether they will ask for that.

The states argue that a weaker rule leaves drivers paying more at the pump over the life of the vehicles, while the department points to lower sticker prices for new cars.

Fuel economy standards, known as CAFE rules, are set by the National Highway Traffic Safety Administration, part of the Transportation Department. They require each automaker's lineup of new vehicles to meet a fleet-wide average in miles per gallon, so the number the agency picks shapes what every manufacturer can sell for the model years covered. The gap between the Biden-era 50.4 miles per gallon and the new 34.9 is about 15.5 miles per gallon, or roughly 30 percent of the old target.