Trucking associations are indeed involved in legal actions related to emission mandates, particularly those imposed by California’s Air Resources Board (CARB). These lawsuits focus on challenging the state’s aggressive truck emissions standards and the enforcement mechanisms California has employed, such as the Clean Truck Partnership (CTP). The core of the dispute lies in whether California has the legal authority to impose and enforce these stringent emissions rules, especially after federal actions have revoked the Environmental Protection Agency (EPA) waivers that previously allowed California to set its own vehicle emissions standards.
The background is that California, aiming to combat air pollution and climate change, developed strict emissions regulations for heavy-duty trucks, including mandates for increasing sales of zero-emission vehicles and reducing nitrogen oxide (NOx) emissions. These rules were supported by agreements with truck manufacturers and engine makers under the Clean Truck Partnership, which sought to phase out internal combustion engines in favor of electric trucks over time.
However, the federal government, particularly under the Trump administration, pushed back against these state-level mandates. In 2025, President Trump signed congressional resolutions that nullified the EPA waivers granted under the Biden administration, effectively revoking California’s authority to enforce these stricter standards. Following this, the U.S. Department of Justice (DOJ) filed lawsuits against California and intervened in lawsuits brought by truck manufacturers and associations, arguing that California’s enforcement of these rules violates the Clean Air Act. The DOJ contends that without the EPA waivers, California cannot legally impose or enforce these emissions standards, and that the Clean Truck Partnership is an unlawful attempt to circumvent federal law.
Several major truck and engine manufacturers, including Daimler Truck North America, Paccar, International Motors, and Volvo Trucks North America, have joined or initiated lawsuits against CARB. These manufacturers argue that the mandates disrupt their business operations and that the state is overstepping its regulatory authority. The DOJ has also sent cease and desist letters to these companies, instructing them to halt compliance with the Clean Truck Partnership and the associated emissions regulations.
California and some allied states, on the other hand, maintain that their unique air quality challenges and climate goals justify their authority to regulate emissions more strictly than federal standards. They argue that the revocation of waivers was improper and that states should retain the right to protect their environments. This legal battle raises fundamental questions about the balance of power between state and federal governments in environmental regulation and could potentially reach the Supreme Court.
For trucking associations, these lawsuits represent a critical front
