Daimler Truck North America LLC v. California Air Resources Board

The federal district court for the Eastern District of California granted heavy-duty truck and engine manufacturers’ motion for a preliminary injunction enjoining the California Air Resources Board (CARB), the Executive Officer of CARB, and Governor Gavin Newsom from implementing, enforcing, attempting to enforce, or threatening to enforce the Clean Truck Partnership, a 2023 agreement in which CARB agreed to undertake certain regulatory actions sought by the manufacturers and the manufacturers agreed to meet certain state clean vehicle standards. The court found that the manufacturers showed that there were clear questions going to the merits of their claim that the Clean Air Act preempts the Clean Truck Partnership and that CARB’s filing of a breach of contract lawsuit on October 27 to enforce the agreement (discussed below in the “New Cases” section) was sufficient to establish concrete and nonspeculative irreparable harm. The court also found that the balance of equities tipped in the manufacturers’ favor. The court denied the preliminary injunction motion to the extent relief was sought on the basis of the manufacturers’ preemption claims for six sets of CARB regulations; a now-superseded May 2025 manufacturers advisory correspondence expressing CARB’s intent to continue enforcing its vehicle standards even if the President signed Congressional Review Act resolutions disapproving the preemption waivers for the standards; and an executive order issued by Governor Newsom in June 2025 that directed CARB to develop clean vehicle regulations. The court found that the manufacturers failed to establish irreparable harm for these claims. The court also found that the manufacturers’ First Amendment claim did not provide grounds for a preliminary injunction.

The manufacturers argued to the court that the Northern District of California was not a proper venue for the case.

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.