Highway taxes are called "user fees" because they are paid by citizens for use of the highways. Despite South Carolina's high level of responsibility, fees paid to the state by each SC citizen are among the lowest in the nation. On a recurring basis, South Carolina invests fewer state dollars per mile than any other state. Fortunately, good stewardship has been the hallmark of SCDOT's existence and the agency has consistently been ranked by the Reason Foundation as one of the nation's most efficient highway agencies. So, the state's taxpayers are getting a lot of "bang for their buck".
The highway user fee is collected at the rate of 16 cents per gallon. It does not grow with the price of fuel. The only way to increase revenues is to consume more fuel (i.e. have more vehicles on the highways). This puts a greater strain on the roads, requiring more maintenance and more construction.
The motor fuel user fee in South Carolina has not been increased or adjusted for inflation since 1987. SCDOT operations are funded through the State Highway Fund, which is over 90% dependent on motor fuel revenues (the national average is 35%).
There are actually four sources of state highway funding in South Carolina: The State Highway Fund and the State Non-Federal Aid Highway Account administered by SCDOT; the C-Fund, under the control of 46 separate County Transportation Committees (CTC's); and, the State Transportation Infrastructure Bank (SCTIB), governed by an independently appointed board. When all four sources are combined for statistical purposes, it shows that the State of South Carolina is 71% dependent on motor fuel revenues for state-source highway funding. This is about double the national average.