Most of the $41 billion in annual federal highway spending is not being adequately tracked by the Federal Highway Administration, a new report from the Government Accountability Office found.

Lax reporting standards by the FHWA make it difficult to track the start-to-finish costs for most projects financed by federal highway dollars, the GAO said in a report released Thursday. All but about $2 billion of the money is passed on to states to build roads and bridges.