The legal battle over automotive emissions has intensified as the United States Department of Justice and Department of Transportation filed a lawsuit against the California Air Resources Board (CARB). The complaint aims to block California from enforcing its stringent carbon dioxide (CO2) and zero-emission vehicle (ZEV) mandates. The federal government argues that these measures violate the Energy Policy and Conservation Act of 1975 (EPCA), which grants the federal government exclusive control over vehicle fuel economy standards.
The lawsuit takes direct aim at two specific CARB regulations: the fleetwide CO2 emission standards and the ZEV sales mandate. The fleetwide standards require automakers to adhere to strict carbon emission targets, currently set at 131 grams per mile for passenger cars starting with the 2025 model year. Meanwhile, the ZEV mandate requires that a percentage of each manufacturer’s sales in California be zero-emission vehicles, with a goal to reach 100 percent by 2035. Although the ZEV sales mandate was invalidated in June 2025 via the Congressional Review Act, CARB has continued to enforce it under an emergency mandate. Details about these contested regulations are outlined in the complaint.
Central to the federal lawsuit is the argument that California’s regulations are inherently linked to fuel economy, which under the EPCA, states are prohibited from regulating. Historically, California has acquired waivers under the Clean Air Act to enforce its emissions rules. However, the DOJ argues that these waivers are not applicable to EPCA’s distinct preemption clause.
In support of the federal position, Attorney General Pam Bondi emphasized that such mandates contribute to higher costs for consumers, aligning with the “Freedom Means Affordable Cars” initiative. Bondi stated, “Oppressive, expensive electric vehicle mandates drive up costs for American consumers and violate federal law.” The DOJ and DOT seek declaratory judgments and permanent injunctions to stop CARB from enforcing or developing these regulations.
This legal confrontation reflects ongoing tensions over state versus federal authority in environmental regulation, following earlier challenges from truck manufacturers and fuel industry groups to California’s ambitious green policies. As legal proceedings unfold, the ramifications of this lawsuit could significantly impact the future of automotive emissions standards across the United States.
The outcome of this lawsuit could set a precedent, potentially influencing not just California, but the nationwide approach to regulate vehicle emissions and combat climate change.