Highway Trust Fund Balance | Funding Sources

The Highway Trust Fund (HTF), established by the Highway Revenue Act of 1956, is the source of revenue for the interstate highway system and other federal-aid highway programs.  The HTF derives its revenue primarily from the Federal motor fuel tax (18.4 cents per gallon on gasoline and 24.4 cents per gallon on diesel fuel as of 2020), in addition to other Federal taxes on truck users and interest on invested balances.  

The HTF has two accounts, the Highway Account, which provides funds for road construction and related surface transportation projects, and the Mass Transit Account, which supports mass transit. 

Highway Trust Fund Balance | Funding Sources

The HTF derives its revenue primarily from the Federal motor fuel tax (currently 18.4 cents per gallon on gasoline and 24.4 cents per gallon on diesel fuel), in addition to other Federal taxes on truck users. These taxes are known as excise taxes. The percent of revenue derived from gasoline and related fuels (excluding diesel) has fallen since 2008, while the percent from heavy vehicle use has risen. As of February 2021, the motor fuel tax on gasoline and diesel has not changed since 1993.

In recent years, the trust fund has needed significant transfers of general revenues to remain solvent. Congress has authorized multiple fund transfers – primarily from the general fund – to keep the fund balance from falling below zero. See "special transfers" in the above visualization to find out more about these transfers and for other sources of income, including interest income on invested balances.

U.S. Department of Transportation, Bureau of Transportation Statistics, Transportation Economic Trends, available at www.bts.gov/product/transportation-economic-trends.