Every mile marker you pass sits on pavement somebody paid for. The money comes from more places than most drivers expect, and the biggest single source has not changed its rate since 1993.

The federal gas tax

The federal tax on gasoline is 18.4 cents a gallon. On diesel it is 24.4 cents. Congress set both rates in 1993 and has not raised them since. The tax is a fixed number of cents, not a percentage, so it does not rise with the price at the pump. Adjusted for inflation, 18.4 cents today buys less than half of what it bought in 1993.

That tax, plus a few taxes aimed at heavy trucks (an annual heavy-vehicle use tax, a tax on truck tires, and a sales tax on new heavy trucks and trailers), feeds the Highway Trust Fund. Congress created the fund in 1956, the same year it authorized the Interstate System, so that road users would pay for roads.

The fund runs short, and has since 2008

Cars go farther on a gallon than they did in 1993. Construction costs have roughly doubled. The tax rate stayed put. The result is a fund that spends more than it takes in every year. Since 2008, Congress has moved more than 270 billion dollars from the general treasury into the Highway Trust Fund to keep it solvent, according to the Congressional Budget Office. The largest single transfer, 118 billion, came with the 2021 infrastructure law.

So the honest answer to "do drivers pay for the roads" is: partly. Fuel and truck taxes cover most of the federal share. General tax revenue covers the rest.

The federal government does not own the interstates

The states do. Washington paid 90 percent of the original construction cost of the Interstate System and still reimburses states for eligible work, but every interstate mile is owned, maintained, plowed and patrolled by the state it runs through. The same is true of the green mile-marker posts. A state DOT sets them, and a state DOT's feed is what reports a closure at one of them.

Federal money reaches the states as reimbursement. A state builds or repairs, submits the bill for the federal share, and gets paid back. The 2021 infrastructure law put about 350 billion dollars into federal highway programs over five years, most of it distributed to states by formula.

State fuel taxes are the bigger pump number

Every state adds its own fuel tax on top of the federal one, and the range is wide: under 10 cents a gallon at the low end, around 70 cents at the high end once fees are counted. A growing number of states index the rate to inflation or to the price of fuel so it does not freeze the way the federal rate did. Some states also charge sales tax on fuel.

State fuel taxes go into a state highway fund, and in many states the constitution restricts that money to roads. That is why a state can be short on transit money and flush on highway money at the same time.

Registration fees, tolls and the electric-vehicle question

Vehicle registration and title fees are the second-largest state source. Tolls are third: a little over 6,000 miles of US road are tolled, and toll roads generally pay for themselves and no one else. The Pennsylvania Turnpike, the New Jersey Turnpike, the Kansas Turnpike and Florida's Turnpike each keep their own mile numbering for that reason. They are separate books.

Electric vehicles pay no fuel tax, so most states now charge them an extra annual registration fee, typically 50 to 250 dollars a year. A few states, including Oregon, Utah and Virginia, run road-usage-charge programs that bill by the mile instead. The mile marker is, in the end, the unit those programs are built on.

Local roads run on property taxes

About three quarters of US road miles are owned by counties, cities and townships, not by any DOT. Those roads are funded mostly by local property and sales taxes, with a share of state fuel-tax money passed down by formula. When a county road washes out, the county pays. When an interstate washes out, the state pays and bills the federal government for its share.

The interstates themselves are a small fraction of the network, roughly one percent of road miles, carrying about a quarter of all miles driven.

Why any of this matters at mile 184

Funding decides what you see out the window. The federal reimbursement rules are why interstates get repaved on a schedule and county roads get patched. State fuel-tax restrictions are why a DOT can widen a highway but not run a bus down it. Toll-road bookkeeping is why the mile marker changes when you pass from I-95 onto the Turnpike.

And the reference posts are a funding tool too. Every state reports its federal-aid road inventory by route and milepoint, which is the same linear system the little green signs mark. The mile marker is how the road describes itself to the people who pay for it.

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Related: Who maintains the roads  ·  Mile markers vs exit numbers  ·  How interstates are numbered  ·  How a crash report reaches your phone

Sources: Federal Highway Administration, Highway Statistics and the Highway Trust Fund fact sheets; Congressional Budget Office, Highway Trust Fund projections; Infrastructure Investment and Jobs Act (2021). Rates and totals checked September 2026.