The U.S. Department of Justice has filed a pair of complaints seeking to stop California from enforcing emissions standards for heavy-duty trucks. 

The DOJ filed complaints in two federal courts on August 15 against the California Air Resource Board (CARB), as part of a challenge to the state's Clean Truck Partnership (CPT) signed in 2023. The partnership between the state and major truck manufacturers was originally designed to give the industry more flexibility to meet California's emissions requirements, and included requirements for phasing out gas-powered trucks in favor of zero-emission vehicles. Although the Biden administration had granted CARB a waiver to preempt less stringent federal emissions standards, President Trump revoked that waiver in June.

“Agreement, contract, partnership, mandate — whatever California wants to call it, this unlawful action attempts to undermine federal law,” said Acting Assistant Attorney General Adam Gustafson. 

Days before the DOJ's complaints surfaced, four truck manufacturers also filed a separate lawsuit, asserting that they've been "caught in the crossfire" between the state and federal government, and that manufacturers haven't been given enough time to comply with California's "aggressive" emission standards. That said, the CPT includes a commitment from manufacturers to stick to the deal's timeline for phasing out gas-powered vehicles in the event of any legal challenges.