The Trump Administration Flunked Its Math Homework


The administration’s clean-cars rollback is riddled with errors. In one case, it forgot to divide by four. In another, it accidentally deleted 700 billion miles of driving.

One of the White House’s most consequential environmental rollbacks may be in self-inflicted legal danger.

In trying to freeze gas-mileage rules for new cars and trucks, Trump officials have hit an unusually damaging snag: They seem to have messed up their math homework.

The Trump administration’s official case for repealing car fuel-economy rules is riddled with calculation mistakes, indefensible assumptions, and broken computer models, according to economists, environmental groups, and a major automaker. The errors may seriously endanger the rule, hampering the White House’s ability to prove the proposal’s benefits exceed its costs and raising questions about whether it can survive an almost inevitable court challenge.

The mistakes range in scope from the comical to the bizarre, from the obviously accidental to the how-did-they-miss-that. In one case, federal employees have forgotten to divide a crucial figure by four. In another, officials have assumed that raising the cost of cars will lead more people to buy them, a violation of the principle of supply and demand. In a third case, the proposal asserts that freezing fuel-economy standards for new cars will lead the owners of old cars to drive their vehicles less.