A federal judge has partially granted a preliminary injunction in a closely watched lawsuit between leading truck manufacturers and the California Air Resources Board (CARB), temporarily halting the enforcement of the state’s Clean Truck Partnership (CTP) while broader questions over federal preemption are litigated.
The decision in Daimler Truck North America LLC et al. v. California Air Resources Board et al. was issued by Judge Dena M. Coggins of the U.S. District Court for the Eastern District of California on October 31, 2025.
Judge Coggins granted the injunction in part, ordering CARB and the State of California to stop implementing, enforcing, or threatening to enforce the Clean Truck Partnership until the merits of the case are resolved. The injunction also bars CARB from seeking specific performance of the partnership in a related Alameda County action. Other elements of the plaintiffs’ request were denied.
In her 45-page order, Judge Coggins emphasized that the limited injunction “preserves the status quo” without pre-judging the validity of California’s regulatory approach to truck emissions. The court noted that the plaintiffs had made a sufficient showing of harm tied specifically to the CTP’s enforcement mechanisms but not to the broader regulatory framework.
The ruling leaves California’s truck and bus rules, including the Advanced Clean Trucks and Advanced Clean Fleets regulations, intact for now. However, the CTP remains on hold pending final resolution.
