The Department of Justice filed lawsuits Thursday against California, accusing the state of unlawfully enforcing emissions regulations for heavy-duty trucks through its “Clean Truck Partnership” with truck and engine manufacturers.
Two complaints were filed against the California Air Resources Board (CARB). The Justice Department says CARB’s actions violate the Clean Air Act, which bars states from regulating vehicle emissions without a preemption waiver from the Environmental Protection Agency (EPA).
Under the Biden administration, the EPA granted California waivers for two CARB regulations that imposed stricter emissions limits on heavy-duty trucks. Those rules were aimed at advancing California’s electric vehicle mandate and could be adopted by other states following California’s standards.
In June 2025, President Donald Trump signed congressional resolutions under the Congressional Review Act that nullified the EPA’s waivers. According to the DOJ, without those waivers, CARB is prohibited from enforcing its regulations, yet it is attempting to do so through the Clean Truck Partnership.
“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 of the DOJ’s Environment and Natural Resources Division. “President Donald Trump and Congress have invalidated the Clean Air Act waivers that were the basis for California’s actions. CARB must respect the democratic process and stop enforcing unlawful standards.”
The lawsuits are part of Trump’s broader effort to roll back electric vehicle (EV) mandates and preserve consumer choice in the automotive market. On his first day back in office, the president signed an executive order that called for the elimination of the EV mandate, saying the promotion of consumer choice is “essential for economic growth and innovation.”
