Daimler Truck North America LLC v. California Air Resources Board

Four heavy-duty truck and engine manufacturers filed an action asking the federal district court for the Eastern District of California to enjoin the California Air Resources Board (CARB) from enforcing certain vehicle standards without a Clean Air Act preemption waiver from the U.S. Environmental Protection Agency (EPA). The manufacturers alleged that they had been “caught in the crossfire” between California’s demands that original equipment manufacturers (OEMs) follow requirements for which EPA preemption waivers had not been obtained or had been disapproved pursuant to the Congressional Review Act and the United States’ orders directing OEMs to disregard the California requirements. The standards the plaintiffs sought to enjoin included the Advanced Clean Trucks, Advanced Clean Fleets, Advanced Clean Cars II, Heavy-Duty On-Board Diagnostic, and Omnibus Low NOx, and Phase 2 Greenhouse Gas standards. They also sought to enjoin CARB from enforcing the 2023 Clean Trust Partnership, which the manufacturers said was intended to harmonize compliance with state and federal law. The manufacturers also sought to enjoin a May 23, 2025 directive by CARB that manufacturers must continue to follow CARB standards and an executive order issued by Governor Gavin Newsom in June 2025 directing continued implementation of the Clean Truck Partnership. The manufacturers asserted claims of Clean Air Act preemption, a claim that the defendants violated the manufacturers’ First Amendment rights as well as their rights under the California’s counterpart to the First Amendment, and claims under the California Administrative Procedure Act.