Updated: 8/1/2024

In September of 2019, the National Highway Traffic Safety Administration (NHTSA) and EPA jointly issued a final rule: The Safer Affordable Fuel-Efficient (SAFE) Vehicles Rule Part One: One National Program (SAFE Part One Rule). In this rule, NHTSA and EPA, under separate statutes, removed states’ authority to regulate greenhouse gas emissions from vehicle tailpipes and to implement zero-emission vehicle (ZEV) mandates. CBF filed a comment letter opposing this Rule.

For decades, EPA has granted California a waiver under the Clean Air Act to establish its Clean Cars program, including greenhouse gas emissions and ZEV (zero emissions vehicle) standards. In the Bay watershed, Delaware, Maryland, New York, Pennsylvania, Virginia, and D.C. have adopted elements of California’s program in order to reduce air pollution and fight climate change. In addition to rescinding California’s authority to establish the Clean Cars program, the Part One Rule also removed other states’ authority to adopt California’s stringent standards.

In response, CBF filed an administrative petition requesting that NHTSA reconsider and withdraw its portion of the Part One Rule. CBF also joined a coalition of public interest groups in filing a petition for review with the D.C. Circuit challenging EPA’s portion of the Part One Rule. Our case was consolidated with other cases filed by NGOs, industry groups, and states.

On January 19, 2021, NHTSA denied CBF’s petition for reconsideration. On January 20, 2021, President Joseph Biden signed Executive Order 13990 on “Protecting Public Health and the Environment and Restoring Science to Tackle the Climate Crisis” which establishes a policy to listen to science and improve public health and protect our environment. The Order directed all executive departments and agencies to review, and as appropriate, take action to address federal regulations finalized during the last four years that conflict with these objectives. On February 8, 2021, the D.C. Circuit granted a motion from the Agencies to hold the consolidated Part One cases in abeyance while the Agencies conduct their review of SAFE Part One.

In April 2021, both Agencies issued proposed rulemakings reconsidering and revising SAFE Part One. CBF joined coalition comments on both EPA and NHTSA’s regulations. NHTSA issued a final rule repealing its portion of SAFE Part One in December 2021 and in March 2022, EPA issued a final rule reinstating California’s waiver and states’ authority to adopt the Clean Cars program.  

CBF’s case has been held in abeyance pending the resolution of separate legal challenges to EPA’ s 2022 action reinstating California’s waiver, consolidated under the lead case, Ohio v, EPA, No, 22-1081.  On April 9, 2024, the D.C Circuit issued its opinion in Ohio v. EPA reaffirming EPA’s authority to grant California a Clean Air Act waiver to issue standards for vehicles that are more stringent than the federal government’s. As a result, CBF’s case and the original challenges to the SAFE Part One Rule were dismissed on July 25, 2024.  

United States Court of Appeals for the District of Columbia Circuit
Competitive Enterprise Institute, et al. v. United States Environmental Protection Agency, et al.
Case No.: 20-1145 (and consolidated cases)
Updated: 4/15/2026

On April 30, 2020, NHTSA and EPA issued The Safer Affordable Fuel-Efficient (SAFE) Vehicles Rule for Model Years 2021–2026 Passenger Cars and Light Trucks (“SAFE Part Two Rule”). In the Part Two Rule, NHTSA weakened existing federal fuel economy standards (fuel economy is the number of miles a car can travel on one gallon of gasoline) and EPA weakened the federal carbon dioxide emissions standards for vehicle tailpipes. The Agencies’ weakening of the federal standards would have resulted in significant increases of climate and air pollution that harm the environment and human health, including the residents and ecosystem of the Bay watershed. 

As a result, in May of 2020 CBF joined a coalition of public interest groups to challenge the Part Two Rule in the D.C. Circuit by filing petitions for review of both NHTSA’s and EPA’s actions.  The petitions were consolidated with other appeals filed by industry groups, state air quality management agencies, and a coalition of states (including the Bay jurisdictions of Maryland, Pennsylvania, Virginia, New York, Delaware, and the District of Columbia).  Petitioners, including the public interest groups, filed opening briefs on January 14, 2021.  Prior to briefing being completed, and due to President Joe Biden’s Executive Order 13990 which required EPA and NHTSA to review and consider revising SAFE Part Two, the consolidated cases were held in abeyance. CBF joined coalition comments on both EPA’s and NHTSA’s proposals to reconsider and revise SAFE Part Two.  

On December 30, 2021, EPA finalized a rule strengthening the greenhouse gas emissions standards for light-duty vehicles, acknowledging that the SAFE Part Two Rule weakened the prior standards.  In April 2022, NHTSA concluded its review of SAFE Part Two and issued a final rule strengthening fuel economy standards.  

However, legal challenges were filed to EPA’s new standards and CBF’s case remains held in abeyance pending the resolution of these challenges. 

On February 18, 2026, EPA issued a Final Rule repealing all greenhouse gas emission standards for light-duty, medium-duty, and heavy-duty vehicles and engines, including the greenhouse gas emission standards in EPA’s prior Rule from December 2021 that strengthened greenhouse gas standards. CBF joined a coalition of organizations from across the country challenging the rescission of these standards in federal court. (See Endangerment Finding Litigation.)

CBF is represented in these cases by Director of Litigation Ariel Solaski.