The state's primary source of revenue for transportation infrastructure comes from motor fuel. Often referred to as the "gas tax," the state charges a $0.28 user fee on each gallon of motor fuel (gasoline and diesel) purchased and an additional $0.0075 per gallon inspection fee.
Motor fuel revenues are allocated to the state's Highway Fund and Infrastructure Maintenance Trust Fund (IMTF) to address repairs and improvements to our state's extensive transportation network. In addition, County Transportation Committees (CTCs) are solely dependent on 3.99 cents from the gasoline user fee.
While South Carolina imposes a flat fee on motor fuels, some states index their rates to keep pace with economic factors in an attempt to maintain buying power. These adjustments are based on formulas chosen by legislators and can be based on factors like inflation (Consumer Price Index), the wholesale price of fuel, highway construction costs or other factors.
South Carolina's motor fuel user fee remains lower than our sister states and lower than the national average for both gasoline and diesel.
Many states have adopted variable rate structures that automatically adjust fuel taxes to maintain purchasing power over time. These rates can be indexed to:
• U.S. Energy Information Administration (EIA) - July 2025
• ARTBA TIAC, Variable Rate State Taxes - July 2025
• Individual state law changes as of July 1, 2025
Click here to learn more about South Carolina’s motor fuel revenue collections and trends.