Highway Trust Fund projected to exhaust its reserves, triggering a 40% cut to federal highway spending

CBO projects the Highway Trust Fund will run out of reserves in fiscal year 2028. The fund is financed primarily by the federal gasoline tax, which has not been raised since 1993 and has lost significant purchasing power to inflation. Upon insolvency, federal law requires highway spending to be cut to match incoming revenue — an immediate reduction of roughly 40%. The 2021 bipartisan infrastructure law transferred $118 billion in general revenue to extend the fund's solvency by approximately five years from an earlier projected exhaustion. Without a new funding mechanism — such as a vehicle-miles-traveled fee, a higher gas tax, or additional general revenue transfers — the shortfall returns.