Washington — General Motors Co., Fiat Chrysler Automobiles NV and Toyota Motor Corp. are siding with the Trump administration in a legal fight with California over the gas mileage rules that govern the nation's automobile industry.

The automakers, together with the Association of Global Automakers, which lobbies for foreign-owned carmakers in Washington, announced Monday they are seeking to intervene in a lawsuit between California and the federal government to argue in favor of the Trump administration's position that Washington should create one set of gas mileage rules for all the nation's cars.

“The decision to intervene in the lawsuit is about how the standard should be applied, not what the standard should be,” John Bozzella, president and CEO of Global Automakers and spokesperson for the new Coalition for Sustainable Automotive Regulation, said in a statement. “By participating we ensure the concerns of consumers, autoworkers, retailers and manufacturers are heard in this dispute.”

Since the earliest days of Trump's presidency, the federal government and California have been at odds over gas mileage rules in a fight that is dividing the auto industry. California is the nation's largest state, which accounts for 12% of the U.S. auto market. Thirteen states and Washington, D.C., have adopted California’s gas mileage rules.

California has reached an agreement with Ford Motor Co., Volkswagen AG, Honda Motor Corp. and BMW AG to voluntarily increase the average fuel economy of their fleets from 2021 levels by 3.7% per year, reaching an average of nearly 50 mpg by 2026. The U.S. Department of Justice has launched an antitrust investigation into that agreement.

GM, Fiat Chrysler and Toyota declined to comment beyond their joint statement. The automakers had faced pressure from Democratic lawmakers to join the voluntarily agreement with California.

“To say I’m disappointed is an understatement, especially given the number of times these companies have told me personally that they wish to avoid costly litigation and regulatory uncertainty," Sen. Tom Carper, D-Del., who is the top Democrat on the Senate Environment and Public Works Committee, said in a statement.

"By aligning themselves with this administration’s reckless and illegal proposal, these companies are actively challenging the rights of states to set their own emissions standards and tackle the climate crisis," Carper continued. "Instead of choosing the responsible path forged by four automakers and the state of California, one that will move us toward the cleaner, alternative fuel vehicles of the future, these companies have chosen to head down a dead-end road."

The Trump administration has moved to revoke California's right to set its own gas mileage rules for vehicles, expressing confidence it will prevail in the legal fight that creates uncertainty for automakers.

California has already sued over the Trump administration's proposed rollback of stringent fuel economy rules that were adopted by the Obama administration in 2012. Michigan has joined California and 21 other states in suing to stop the Trump administration from revoking the Golden State's authority to set emission standards for cars and trucks.

klaing@detroitnews.com

202-662-8735

Twitter: @Keith_Laing