CALIFORNIA – Four major truck manufacturers – Daimler Truck, PACCAR, Volvo Group North America, and International Motors, filed a lawsuit, August 11, against the California Air Resources Board (CARB) in the U.S. District Court for the Eastern District of California.
The lawsuit challenges California’s enforcement of its clean truck rules after the federal government revoked the EPA waiver that allowed the state to set stricter emissions standards.
CARB’s Advanced Clean Trucks (ACT) regulations mandate increasing sales of zero-emission vehicles.
Impossible situation
The truck manufacturers (OEMs) say they are stuck in an “impossible” situation because two authorities are giving them conflicting orders.
“On the one hand, California insists that Plaintiff OEMs must follow CARB’s standards, including CARB’s truck and engine certification requirements, or be excluded from the California market…” according to court documents.
On the other hand, they argue that the U.S. Department of Justice issued cease-and-desist letters declaring CARB’s standards are invalid, stating only EPA regulations apply, and that CARB’s Clean Truck Partnership is blocked by federal law.
Selling without certification can lead to fines up to $48,788
The truck makers said prior to filing the lawsuit, they sought clarification from CARB regarding their legal obligations under the Clean Truck Partnership and CARB’s underlying emissions standards.
“To date, CARB has declined to address the concerns raised by regulated parties, despite requests by the Plaintiff OEMs and their trade associations, and instead issued the May 23, 2025 MAC and Executive Order N-27-25 without any dialogue with industry,” according to court documents.
The May 23, 2025 Manufacturers Advisory Correspondence (MAC) states CARB will continue enforcing certification requirements, which manufacturers must meet to legally sell trucks in California. Selling without certification can lead to fines of up to $48,788 per violation.
However, the federal Clean Air Act prohibits CARB from issuing such certifications without an EPA waiver – which has recently been revoked.
Despite this, CARB says it will keep accepting and processing certification applications for upcoming vehicle models to enable legal sales in California.
Restricts constitutional right to challenge regulations
Truck makers say California’s Clean Truck Partnership unlawfully restricts their constitutional right to challenge regulations and threatens penalties if they do.
They’ve sued to clarify their legal obligations and stop these rights violations, seeking a quick court decision.
