Every gallon of gas you buy in Wisconsin includes about fifty-one cents in taxes — roughly thirty-three cents to the state, eighteen to the federal government. People grumble about it. But here's what that money does: it builds and maintains the roads you're driving on.

Wisconsin's gas tax used to be indexed to inflation — but lawmakers eliminated that in 2006. It's been frozen at thirty-three cents for twenty years. The state has lost an estimated four billion dollars in transportation revenue because of that decision. The federal gas tax is even worse — eighteen point four cents since 1993. Over thirty years, no adjustment, and nearly half its purchasing power gone.

That's one reason America's roads and bridges keep falling behind. The Highway Trust Fund has been running short for years, and Congress keeps patching it with general tax revenue rather than raising the gas tax — because nobody wants to be the politician who raised gas prices.

Meanwhile, the oil and gas industry has received federal tax breaks and subsidies for over a century. The roads wear out. The subsidies don't.

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Wisconsin's gas tax is 32.9¢/gallon (state excise) plus a 2¢ petroleum inspection fee. The tax was once indexed to CPI, but state lawmakers eliminated the indexing provision in 2006. The rate has been frozen ever since — unchanged for 20 years. The Wisconsin Transportation Builders Association estimates the state has lost approximately $4 billion in transportation revenue over the past two decades as a result. The gas tax is the single largest source of revenue for WisDOT to fix, maintain, and improve Wisconsin's roads. Gas tax revenue contributed about $1.07 billion to the state transportation fund in 2021-22, roughly 45% of total fund revenue. Wisconsin ranks 12th highest among states. (WI Legislative Fiscal Bureau, Informational Paper 40)

The federal gas tax — 18.4¢/gallon — has not changed since October 1, 1993. It is not indexed to inflation. In today's dollars, it has lost roughly 45% of its purchasing power. (EIA FAQ)

Total Wisconsin gas tax: About 51.3¢/gallon combined. For comparison: California charges 70.9¢, Illinois 66.4¢, and Alaska just 9¢. The national average is about 33.5¢ as of January 2026. (Tax Foundation; EIA state tax data)

The Highway Trust Fund keeps running short. Congress has transferred over $275 billion in general fund revenue since 2008 to keep the HTF solvent — essentially using income taxes to make up for a gas tax that hasn't been raised in over 30 years. (Congressional Budget Office)

Fossil fuel industry subsidies have existed for over a century. The federal government has provided direct tax expenditures to oil, gas, and coal companies since at least 1918. See CM-33 (Who's Subsidizing Whom?) for detailed subsidy data.

Related Civic Minute segments: What's in a Gallon of Gas (CM-22), Who's Subsidizing Whom? (CM-33)