The economy of the United States depends on our nation’s transportation infrastructure. Every day, tens of millions of people commute to work in the United States using public roads and transportation systems. Billions of dollars’ worth of freight is transported using the nation’s highways, railroads, ports, and inland waterways (Fact 3). Significant public investment—at all levels of government—is required to maintain this system, conduct periodic repairs, and expand our nation’s transportation systems to safely handle movement of greater numbers of goods and people. A well-functioning system of mass transportation is both a substitute for and a complement to our nation’s highway system (Fact 4), but funding for these systems is also stretched thin.

The facts make it clear that the state of public financing for transportation infrastructure warrants serious attention. Federal spending as a share of GDP has fallen (Fact 1) and the federal Highway Trust Fund (HTF)—the designated source of revenue for spending on our nation’s highways—is about to run out of money (Fact 2). The primary source of funding for the HTF is the federal gas tax, but that tax has not been raised since 1993. Of course, state and local governments also play an active role in both the funding and building of infrastructure projects. Interestingly, there is large variation across states in both their reliance on state-level gas taxes (Fact 5) and the amount of federal funding states receive for the construction and maintenance of roads (Fact 6).

An efficient and reliable transportation infrastructure facilitates the transactions that enable the economy to grow and to create private sector jobs. Many observers agree on the need for increased investment in America’s aging infrastructure, including roads, bridges, and airports. However, determining how to fund and finance infrastructure investment presents important policy and political challenges. The purpose of this document is to provide objective background facts to help guide those necessary policy and political discussions.