Federal gas tax freeze (1993)
The federal gas tax has been 18.4 cents per gallon since 1993. Congress has declined to raise it for over three decades, and the Highway Trust Fund has repeatedly faced shortfalls requiring transfers from general revenue.
Federal road spending has been propped up by general fund transfers since 2008.
The federal impasse pushed funding decisions to the states, which must find their own solutions.
Michigan's pilot is a state-level response to a revenue problem Washington has refused to solve for 30 years.
