The newly confirmed transportation secretary, Sean Duffy, signed an order on Tuesday seeking to roll back key fuel economy standards set by President Joseph R. Biden Jr.
The order is the latest effort by the Trump administration to roll back initiatives introduced by the Biden administration aimed at promoting electric vehicles and reducing greenhouse gas emissions.
In a memo to the National Highway Traffic Safety Administration, Mr. Duffy instructed the agency to re-evaluate fuel economy rules for new cars and trucks through the end of the decade. The order came as one of Mr. Duffy’s first acts as the head of the Department of Transportation.
The Biden fuel economy standards require American automakers’ passenger cars to average 65 miles per gallon by 2031, up from 48.7 miles last year. The average mileage for light trucks, including pickup trucks and sport utility vehicles, would have to reach 45 miles per gallon, up from 35.1 miles per gallon.
Some automakers have criticized the rule as a costly distortion of the market.
“Artificially high fuel economy standards,” the transportation secretary’s memo said, “impose large costs that render many new vehicle models unaffordable for the average American family and small business owner.”
Mr. Duffy, a former Wisconsin representative, was confirmed earlier in the day despite a late wave of opposition from some Democrats upset about the Trump administration’s freeze on federal grants and loans. The final vote was 77 to 22.
In his memo, Mr. Duffy expressed doubts about whether the current fuel economy standards accurately reflect the United States’ abundant oil reserves and refining capabilities. The memo states that these standards may not take into account the vulnerabilities of the U.S. electricity grid or the national security risks of relying on foreign sources for materials, particularly those used in electric vehicle batteries.
Mr. Duffy’s memo directs the National Highway Traffic Safety Administration to review all fuel economy standards for vehicles from the 2022 model year onward.
