Trump’s Fuel-Economy Rollback: The 2031 MPG Proposal and What Remains Unknown

President Donald Trump said on September 26, 2026, that he had approved new fuel-economy standards to replace Biden-era rules, describing the move as ending what he calls an “EV mandate.” But the administration had not released the final rule alongside the announcement. Officials said the Transportation Department would unveil it Monday, leaving its precise requirements unclear in the reporting available at the time. 211

What the earlier NHTSA proposal would change

The earlier National Highway Traffic Safety Administration proposal would lower the projected fleetwide fuel-economy target for new cars and light trucks in model year 2031 from about 50.4 mpg to 34.5 mpg. That is a fleet average—not a requirement for every individual vehicle—and it describes the proposal, not necessarily the final rule. 2

Price claims versus projected trade-offs

Trump said the new standards would reduce vehicle prices, give consumers more choice and support U.S. auto manufacturing. Those are the administration’s stated expectations; the available reporting does not establish them as confirmed outcomes of the final rule. 24

The earlier proposal’s projected effects point to a trade-off: lower upfront vehicle prices, but more fuel consumed, higher fuel spending over a vehicle’s lifetime and greater carbon dioxide emissions. A lower purchase price would not, by itself, show that a vehicle costs less to own overall. 2

Why environmental groups object

Environmental groups have criticized the planned rollback over concerns that weaker efficiency standards could mean more gasoline use and climate pollution. They also warn that drivers could face higher fuel costs, offsetting some savings at purchase. The scale of those effects—and whether the final rule differs from the earlier proposal—cannot be determined from the announcement alone. 12

What is still uncertain

The key distinction is between Trump’s announcement and the published rule. The announcement said he had approved new standards, while reports said the Transportation Department planned to release the final text on Monday. Until that text is available, the 34.5-mpg figure and the projected price, fuel-use and emissions effects should be treated as details of the earlier proposal, not confirmed terms or outcomes of the final rule. 2511