August 23, 2021
![Highway Trust Fund's excise tax receipts over time Highway Trust Fund's excise tax receipts over time](https://www.taxpolicycenter.org/sites/default/files/fiscal-facts/ff_detailed_08.23.2021_1.png)
Fact:
Taxes on motor fuels are the biggest revenue source for the Highway Trust Fund, but those tax rates have not changed since 1993. In recent years, transfers from the General Fund have been necessary to support trust fund spending.