The U.S. government has officially reduced the gas mileage requirements for new cars and trucks to allow manufacturers more flexibility in their vehicle lineups. As part of the final rules issued on Sept. 28, the Trump administration will terminate fuel economy credit trading in 2028, removing a regulatory mechanism that previously allowed automakers to offset lower-efficiency models with more efficient ones.

The updates set a fuel economy target of 34.5 mpg by 2031, down from the 50.4 mpg goal established under the Biden administration. The rollback removes electric vehicles as a source of extra credit for manufacturers, though the administration's own estimates suggest the move may increase emissions and gasoline use. Because Congress already eliminated fines for missing fuel targets, the new standards are largely symbolic in terms of enforcement.