"The sudden failure and collapse of the I-35W Interstate System bridge in Minneapolis has raised policy concerns in Congress regarding the condition of the nation's transportation infrastructure in general, and in particular the federal role funding, building, maintaining, and ensuring the safety of roads and especially bridges in the United States. Highway bridges are of particular interest both because of the recent tragedy in Minneapolis and the catastrophic results of a major bridge failure, in terms of loss of life and economic impact. Of the 600,000 public road bridges listed in the National Bridge Inventory, roughly 12%, or 74,000, are classified as structurally deficient. This is, however, roughly half the number classified as deficient in 1990. Given the I-35W collapse, however, even this lower number of deficient bridges leaves Americans potentially exposed to what some might consider an unacceptable level of risk. A policy question is how fast can and should the remaining deficient bridges be replaced or improved. At current annual spending levels, roughly $10.5 billion (2004 dollars at all levels of government), the bridge investment backlog (in dollar terms) would be reduced by roughly half by 2024. Reducing the backlog to near zero during the same period would require an estimated annual spending rate of roughly $12.4 billion (in 2004 dollars). The Emergency Relief Program (ER), administered by the Federal Highway Administration (FHWA), provides funding for bridges damaged in natural disasters or that were subject to catastrophic failures."
CRS Report for Congress, RL34127