USA – Daimler Truck North America LLC of Portland, Oregon is leading a lawsuit against the California Air Resources Board as it seeks to block the state of California from enforcing emissions standards that were rendered null and void by the federal government in June.

On 11 August, Daimler, Volvo Group North America, Paccar, and International jointly filed a complaint with the federal district court for the Eastern District of California, requesting that it prohibits the enforcement of various regulations and standards that are still in place in the state. The lawsuit seeks to enjoin the following:

• The “Advanced Clean Trucks” regulation, consisting of a sales mandate for zero emission vehicles and a one-time reporting requirement; 

• The “Advanced Clean Fleets” regulation, requiring the phase out of new combustion-powered trucks by model year 2036; 

• The “Advanced Clean Cars II” regulation, mandating that all new trucks sold in California in 2035 will be zero emission; 

• Onboard diagnostic requirements for heavy-duty vehicles with engines rated at 525 bhp or higher; 

• The “Heavy-Duty Low NOx” regulation for nitrogen oxide emissions; 

• “Phase 2 Greenhouse Gas” standards for medium- and heavy-duty vehicles, enforced from 2018 through 2027.

The manufacturers also seek to block a 23 May 2025 directive from the board requiring them to follow CARB standards and an executive order from the state governor (June 2025) mandating the continuation of the “Clean Truck Partnership”.

California’s power to set its own vehicle emission standards was put under notice when President Trump came into office in 2025. The state repealed its zero-emission vehicle mandate when the Environmental Protection Agency withdrew a waiver in January 2025 allowing California to enforce zero emission quotas on fleets. Subsequently in June, Trump signed three congressional resolutions to support the agency’s action and to rescind other waivers and approvals granted to the state.

In a statement, International said that manufacturers “have been placed squarely in the crossfire” between the state of California and the federal government, “forcing us to operate in an environment where the rules change midstream and compliance targets shift with little warning”. It stated further that the current situation makes it “impossible” to plan ahead “with confidence”. The company requests a “swift resolution” from the court in order to provide greater “regulatory certainty”.