While the Highway Trust Fund, backed by motor fuel taxes and several other Federal taxes, provides about 91 percent of surface transportation funding, the remaining revenue comes from the Federal General Fund - about 9 percent. Most of the Federal funding derived from the General Fund is used to support intercity passenger rail and Amtrak through FRA and mass transit capital investment grants through FTA. Other uses of the General Fund include USDOT agency operations, emergency highway relief beyond authorized levels, and transportation research.
All funding administered by the FRA comes from the General Fund. This includes state intercity passenger rail capital assistance to states and operating, capital, and efficiency incentive grants to Amtrak.
New Starts and Small Starts fixed guideway capital projects administered by FTA under Title 49, Section 5309.