Gas prices continue to skyrocket due to the ongoing U.S. war against Iran, which has interrupted global oil shipments. On Monday, President Donald Trump proposed one way to help drivers that are paying more at the pump: a holiday from the federal gas tax.

In an interview with CBS News, Trump said, “We’re going to take off the gas tax for a period of time, and when gas goes down, we’ll let it phase back in.”

“It’s a small percentage, but you know, it’s still money,” Trump added.

There’s a few major problems from this plan becoming reality. For one, Trump can’t do this kind of federal gas tax pause on his own. Suspending the tax, which currently is 18 cents per gallon for regular gas and 24 cents for diesel, requires congressional approval. So far, Congress has not approved a federal gas tax holiday, although there is bipartisan interest in Trump’s proposal of a federal gas tax suspension. But drivers would pay a price in the long run.

Modest savings would come at the cost of bumpy roads for drivers.