According to a detailed breakdown of 2013 federal highway funding obligations by the Government Accountability Office, states used just less than 6 percent of the $41 billion contract authority received on construction projects to build new roads or bridges.

The largest portion of federal aid went toward upkeep of states’ existing systems. Fifteen percent of contract authority went toward adding new capacity to existing highways and bridges. In addition, 8.5 percent of aid supported operations including engineering, right-of-way acquisition, planning and utilities. Another 6.3 percent went toward safety projects, while smaller amounts went toward areas such as federal lands, research, enhancements and environmental work.