Five groups ask US appeals court to review eased CAFE rules

Five environmental and consumer advocacy groups have taken the Trump administration’s revised fuel economy rules to a federal appeals court. Their petition for review, filed on Friday, October 2, 2026, argues that looser mileage requirements will mean more gasoline burned and higher bills for drivers. The rules themselves were announced the previous Monday.

What changed in the CAFE standards

The dispute centers on the Corporate Average Fuel Economy (CAFE) standards, which govern how many miles per gallon the vehicles a manufacturer sells must be able to cover. According to the Associated Press report carried by Yahoo, the revised standards require carmakers to reach a fleet-wide average of 34.9 mpg by 2031. Rules adopted under the Biden administration had pointed to a projected 50.4 mpg.

Fuel economy requirements date back to the energy crisis of the 1970s, and over the decades they have helped raise the average efficiency of cars on American roads. Electrek adds that a manufacturer whose fleet falls short of its required average faces a fine for each non-compliant vehicle it sells.

The administration’s argument

In presenting the new standards, the Department of Transportation said they would lower the average upfront price of a new vehicle by $1,300, reduce yearly oil consumption and give automakers a wider choice of the models they build. Transportation Secretary Sean Duffy described the earlier approach as an illegal mandate that pushed manufacturers toward costlier electric vehicles, a product he said American families did not want.

The Transportation Department and the National Highway Traffic Safety Administration (NHTSA) did not immediately respond when the Associated Press asked them to comment on the lawsuit.

Who filed, and what they claim

The petition names Duffy and Jonathan Morrison, the NHTSA administrator, as respondents. NHTSA is the agency that sets the CAFE rules. The groups behind the filing are Public Citizen, the Sierra Club, Environmental Defense Fund, Conservation Law Foundation and the Center for Biological Diversity, whose Climate Law Institute is involved.

The petitioners say that weaker efficiency requirements will raise costs for drivers and push up vehicle emissions, a leading cause of climate change. In a statement, Katherine Garcia, who directs the Sierra Club’s Clean Transportation for All program, said that rolling back fuel-efficient cars was unlawful and would make drivers spend more on gasoline while leaving communities with dirtier air. Robert Weissman, co-president of Public Citizen, said consumers need more fuel-efficient choices and should be able to buy cars that deliver more miles per gallon and more miles per dollar.

Electrek describes the filing as a short petition that does not yet lay out the legal arguments the groups intend to make.

Figures cited by Electrek

Electrek, an outlet that covers electric vehicles and is openly critical of the rollback, reports that the Department of Energy’s own numbers show the change adding 76 cents to the price of a gallon of gasoline, and that vehicles would use 45% more fuel by 2031. It also states that the large majority of the 68,294 public comments submitted while the rule was being proposed opposed it. These figures come from that outlet’s account rather than from the Associated Press text, so readers should treat them as reported claims until the underlying documents are consulted.

Emissions and fuel prices in context

The Associated Press cites the Environmental Protection Agency for two reference points. Each year, a typical passenger vehicle gives off 4.6 metric tons of carbon dioxide, and in 2022, the latest year with data, transportation accounted for 28% of all greenhouse gas emissions in the United States.

The filing also arrives while drivers are paying a lot at the pump. The national average for a gallon of gasoline stood at $4.40 on the day of the filing, compared with $3.16 a year earlier and roughly $2.98 in the days before the war involving Iran began in late February.

What happens next

A petition for review is only the first step in challenging a federal rule, and the groups have not yet laid out their arguments. Neither side can point to an outcome. The filing does show how far apart they are on the central trade-off: lower sticker prices for new vehicles on one hand, fuel costs and emissions over a car’s lifetime on the other.

Featured image. Source: Wikimedia Commons. Credit: Jamie Street. License: CC0.