US Seeks to Invalidate California Higher Emissions Standards
By Reuters | 12 Mar, 2026

Trump wants to impose lax Federal tailpipe emissions standard on California which has been setting its own more stringent standard since 2022.

President Donald Trump's administration on Thursday sued California, claiming the state's zero-emission vehicle and tailpipe greenhouse gas emissions rules are illegal and preempted by federal law.

The U.S. Transportation Department sued the California Air Resources Board in U.S. District Court in California over vehicle rules that remain in place after Trump signed legislation last year to overturn California’s Advanced Clean Cars II rules that aim to phase out new gasoline-powered cars by 2035.

The lawsuit wants a ruling declaring that all zero-emission vehicle mandates by California are unlawful and unenforceable.

"This litigation will help automakers design and produce cars and trucks to meet one federal fuel economy regulation," said Jonathan Morrison, who heads the National Highway Traffic Safety Administration.

California won approval in 2022 from the Environmental Protection Agency for its current vehicle rules known as Advanced Clean Cars I, which the state says remain in effect. 

The California Air Resources Board declined comment. A spokesperson for California Governor Gavin Newsom said the lawsuit is meritless and the state will not back down.

He added as Americans face higher gasoline prices since the start of the Iran war, "the Trump administration sued California for advancing cleaner, cheaper cars that free drivers from the grip of foreign oil markets and the bad actors who stand to profit from global instability."

This is the latest in a series of efforts by the Trump administration to bar California from setting vehicle rules. In August, it sued California to stop the state from enforcing stringent emissions standards for heavy-duty trucks.

California's rules require automakers to sell a rising number of electric vehicles and meet increasingly stringent limits on tailpipe emissions.

Those rules are much stricter than those imposed by the Trump administration, which plans to roll back federal fuel economy rules.

California contends the fuel savings for consumers from the rules far exceed the higher upfront costs of EVs.

Congress rescinded authority for California to outlaw traditional gas-powered vehicles after 2035 after Toyota and the Detroit Three lobbied Congress and the White House for significant relief from California's emissions regulations. 

The White House also significantly weakened federal tailpipe rules and Congress passed legislation to stop collecting penalties for not meeting vehicle tailpipe standards.

A group representing major automakers did not immediately comment.

(Reporting by David Shepardson; Editing by Deepa Babington and David Gregorio)