Where Does Gas Tax Money Go?

Guides · October 7, 2026

Every gallon of gas you buy carries 18.4 cents of federal tax, and none of it goes into the government's general checking account. It flows into a dedicated pot called the Highway Trust Fund, which splits it three ways before it ever touches a road. Diesel carries 24.4 cents and goes to the same place.

Where gas tax money goes: the federal split

The Highway Trust Fund dates to 1956 and runs on the user-pays principle: drivers fund the roads they wear out. The tax is collected at the wholesale level before fuel reaches the pump, so you never see a line item. It is baked into the price on the sign. The transit slice arrived in 1982, when the Surface Transportation Assistance Act divided the fund into a Highway Account and a Mass Transit Account.

One tenth of a cent sounds like a rounding error, but it has its own story. The Leaking Underground Storage Tank fund cleans up gas station tanks that leak petroleum into soil and groundwater. Your gas tax pays to clean up old gas stations. Nobody told you, and now you know.

Then your state takes its cut on top

The federal tax is only the first layer. State gas taxes stack on top of it, and they range from roughly 9 cents a gallon in the lowest states to over 70 cents in the highest. Those dollars fund state road funds and transportation budgets: maintenance, state troopers in some states, local construction projects. A gallon in California and a gallon in Alaska carry almost the same federal tax and wildly different state taxes, which is most of why pump prices vary by state.

Run your own annual number: the average driver burns about 500 gallons a year, so a 50-cent combined rate is $250 a year out of pocket, nearly all of it invisible inside the pump price. Our yearly gas tax calculator guide works the math for your state.

Why the fund keeps running dry

Here is the uncomfortable part of the answer. The federal rate has not been raised since 1993, when it went to 18.4 cents. It is a flat cents-per-gallon charge, not a percentage, so inflation has quietly eaten about half of its purchasing power while cars got more fuel efficient and EVs arrived, paying nothing at all. Since 2008, the Highway Trust Fund has spent more than it takes in every single year. Congress has transferred roughly $275 billion from the general fund to keep it solvent over 15-plus years. In fiscal year 2025 alone, the gap between what drivers paid in and what roads cost hit $30.6 billion.

The Congressional Budget Office projects the fund could run dry around 2028 without further action. So the current direction of money is, ironically, reversed: the gas tax was supposed to keep road money separate from everything else, and now everything else is paying for the roads. Whether Congress raises the rate, indexes it, or moves to mileage-based fees is the open question nobody in Washington has answered yet.