April 4, 2023 | Cara Horowitz and Gabriel Greif

On April 3, 2023, faculty at the Emmett Institute on Climate Change and the Environment filed an amicus brief in the U.S. Court of Appeals for the District of Columbia Circuit supporting the National Highway Traffic Safety Administration’s consideration of California’s Zero-Emission Vehicles standards in its rulemaking adopting nationwide fuel-economy standards.

The brief responds to claims by some parties that California’s Zero-Emission Vehicles standards are preempted by the Energy Policy and Conservation Act (EPCA) as “relating to” fuel-economy standards and that NHTSA therefore may not consider them in its rulemaking. The amicus brief emphasizes California’s clear authority to create ZEV standards under the Clean Air Act, an authority Congress recognized when it passed EPCA and subsequent legislation.

This brief is related to a recent amicus that Emmett Institute faculty filed in State of Ohio et al. v. Environmental Protection Agency et al., in which Petitioners directly challenged the U.S. Environmental Protection Agency’s authority to grant a long-held waiver of preemption to California to regulate vehicle emissions more stringently than the federal government. Petitioners in Ohio v. EPA advanced similar preemption theories to those placed at issue by Petitioner-Intervenors here.

It was filed as part of the Frank G. Wells Environmental Law Clinic on behalf of Congressional Democrats by Emmett Institute Executive Director Cara Horowitz along with Emmett/Frankel Fellow Gabriel Greif. The amici members of Congress are Sen. Tom Carper (D-Del), chairman of the U.S. Senate Committee on Environment and Public Works, and Rep. Frank Pallone Jr. (D-New Jersey), Ranking Member of the House Committee on Energy and Commerce. The pair has chaired the two committees with jurisdiction over the Clean Air Act. 

This brief addresses important questions about the relationship between two longstanding federal statutes: the Clean Air Act, which provides for the protection of public health and air quality through the creation of motor vehicle emission standards, and the Energy Policy and Conservation Act of 1975, which governs federal fuel economy standards. Sometimes, standards that regulate pollution from cars also affect fuel economy. Does that mean EPCA preempts such air pollution standards, as Fuel Intervenors argue? For nearly 50 years, including at EPCA’s enactment and at every major opportunity since, Congress has been clear that the answer is “No.” Motor vehicle air pollution standards—including, explicitly, California’s Zero-Emission Vehicles standards—are not preempted by EPCA, even if they affect fuel economy. This brief explains why.

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