Truck OEMs Challenge Clean Truck Partnership in Federal Court

(Advanced Clean Tech News) Four of the nation’s largest heavy-duty truck makers have filed a lawsuit in the U.S. District Court for the Eastern District of California, challenging the California Air Resources Board (CARB) and Governor Gavin Newsom’s ability to enforce certain state emissions regulations and the 2023 Clean Truck Partnership agreement.

Plaintiffs Daimler Truck North America, International Motors, PACCAR, and Volvo Group North America allege that California is attempting to require compliance with heavy-duty truck emissions standards that Congress recently preempted under the federal Clean Air Act. The complaint states that these manufacturers are now caught between conflicting directives — California requiring adherence to its rules, and the U.S. Department of Justice instructing them to stop following the same standards.

At the center of the dispute is the Clean Truck Partnership, an agreement announced in July 2023 between CARB, several truck manufacturers, and the Truck and Engine Manufacturers Association. The plaintiffs state that while the agreement was intended to align state and federal standards, it is now being applied to enforce regulations that no longer have federal waivers. The lawsuit also challenges provisions in the agreement that plaintiffs say limit manufacturers’ ability to contest CARB regulations.

According to the filing, Congress in June 2025 passed — and the president signed — resolutions under the Congressional Review Act that nullified EPA’s earlier waivers allowing California to implement three key programs: the Advanced Clean Trucks regulation, the Omnibus Low NOx regulation, and parts of Advanced Clean Cars II. The U.S. Department of Justice has since advised manufacturers that these programs, and the Clean Truck Partnership itself, are preempted by federal law.

California has filed its own lawsuit against the U.S. Environmental Protection Agency and the federal government, challenging the validity of those Congressional actions. That case is pending in federal court.

In their suit, the truck makers are asking the court for declaratory and injunctive relief to clarify their regulatory obligations and prevent enforcement of state standards they argue are invalid under federal law. The complaint also raises constitutional claims related to free speech and the ability to petition the government. READ MORE

Excerpt from MSN/The Hill: As the nation’s major truckmakers seek to abandon California’s stricter-than-federal emissions rules, experts are weighing whether this U-turn could allow new players to disrupt the market.

“All your competitors just announced their strategy,” Craig Segall, former deputy executive officer and assistant chief counsel of the California Air Resources Board (CARB), told The Hill.

This now unmasked strategy — an about-face on compliance with the Golden State’s heavy-duty vehicle standards — came to light this week when four manufacturers sued California regulators over the matter.

Then, Friday, the Department of Justice sued California about the same partnership, in a bid to “advance President Donald J. Trump’s commitment to end the electric vehicle (EV) mandate.”

The week’s initial lawsuit, filed Monday by Daimler Truck, International Motors, PACCAR and the Volvo Group, alleged the federal government had deemed California’s emissions rules “unlawful” in June.

At the time, President Trump signed off on three congressional resolutions revoking a Biden administration waiver that had allowed the state to set these rules. Under the 1970 Clean Air Act, California can create emissions standards that are stricter than federal norms but must acquire a waiver from the Environmental Protection Agency to do so. READ MORE

Excerpt from The Hill: The Trump administration is seeking to sue California to halt the state from enforcing its effort to electrify its truck fleet.

Now, the Trump administration and truckmakers are accusing the state of enforcing the now-overturned standards through its “Clean Truck Partnership” under which truck companies agreed to follow the state’s rules in exchange for some additional flexibility.

The California Air Resources Board, which is in charge of the truck rules, declined to comment.

At issue are California rules including the Advanced Clean Trucks rule, which would require a large percentage of trucks sold in the state to be electric by 2035.

In 2023, a group of truckmakers agreed to meet California’s standards in exchange for some concessions from the state in what became known as the Clean Truck Partnership.

Under the Clean Air Act, California is required to get federal approval for its auto regulations. The Biden administration approved the state’s rule.

This year, however, Congress and President Trump approved a resolution using the Congressional Review Act to overturn the approval of the California rule.

The move occurred despite determinations from the Senate parliamentarian and the Government Accountability Office, a nonpartisan congressional watchdog, which said that it was not subject to the Congressional Review Act.

Now, the Trump administration is arguing in court that California has sought to enforce its rules through the Clean Truck Partnership, describing the state’s effort as a “a stunning act of defiance.”

Earlier this week, Daimler Truck North America, International Motors, Paccar and Volvo Group North America sued the Trump administration to try to axe the state’s rules and the partnership. READ MORE