	Background

The United States has approximately 608,000 bridges on public roads subject to the National Bridge Inspection Standards mandated by Congress. In 2013, approximately 64,000 bridges, or 10% of the total number of bridges, were classified as structurally deficient, as compared to 138,000 in 1990. The share of bridges classified as functionally obsolete in 2013 was 14%. The funding increase was largely due to the American Recovery and Reinvestment Act of 2009 ( P.L. 111-5 ; ARRA). According to FHWA, to keep the backlog at the 2010 level through 2030 would require $8.9 billion annually (in 2010 dollars), less than the level of spending in 2010. FHWA, however, does not make the determination as to which bridges should benefit from federal funding. The 2012 surface transportation reauthorization, the Moving Ahead for Progress in the 21 st Century Act (MAP-21, P.L. Bridge improvements remain eligible for funding under two programs created by MAP-21 that distribute funds to the states under formulas specified in the law, the National Highway Performance Program (NHPP) and the Surface Transportation Program (STP). FHWA is involved in the project decision-making process in two significant ways. Under MAP-21, which eliminated the HBP, the states have even more freedom to decide how much of their federal surface transportation grants to spend on bridges. States may use this information to identify which bridges need replacement or repair. The condition of roads has not experienced the same degree of improvement as the condition of bridges. The terms "structurally deficient" and "functionally obsolete" are not synonymous with "unsafe." Under MAP-21, FHWA is to develop performance measures in regard to bridges. Federal Pressure for State Bridge Spending

To encourage state spending on structurally deficient bridges, MAP-21 sets a penalty threshold under the NHPP: any state whose structurally deficient bridge deck area on the National Highway System within the state's borders exceeds 10% of its total National Highway System bridge deck area for three years in a row must devote NHPP funds equal to 50% of the state's FY2009 Highway Bridge program apportionment to improve bridge conditions during the following fiscal year and each year thereafter until the deck area of structurally deficient bridges falls to 10% or below. Even if a state were required to spend more of its federal highway funding on bridges (and therefore less on roadway projects) due to this penalty, its mandated spending on deficient bridges would be less than was required prior to the enactment of MAP-21. Emphasize public-private partnerships (P3s) as a mechanism to help reduce the number of structurally deficient bridges, for example, by allowing states to offer long-term leases of toll facilities to private investors in return for large up-front payments that could be used to supplement normal state and federal spending on bridge replacement and repair. Redirect Spending Away from Off-System Bridges

Historically, nearly all federal highway funding was restricted to roads and bridges on the federal-aid highway system.
Of the 608,000 public road bridges in the United States, about 64,000 (10%) were classified as structurally deficient in 2013, and another 84,000 (14%) were classified as functionally obsolete. The number of structurally deficient and functionally obsolete bridges has been declining steadily for more than two decades, and those that remain are not necessarily unsafe. Nonetheless, several high-profile bridge failures, including the 2013 collapse of a bridge on Interstate 5 in Washington State, have drawn public attention to the condition of bridges on federal-aid highways.
As it debates reauthorization of the Moving Ahead for Progress in the 21st Century Act (MAP-21; P.L. 112-141), the 2012 law which reauthorized federal surface transportation programs, Congress may consider mandating increased spending on bridge improvements. The choice Congress makes will largely determine how quickly deficient and obsolete bridges will be replaced or improved. At the spending level of 2010, which included a significant amount of money provided by the American Recovery and Reinvestment Act of 2009 (P.L. 111-5), the Federal Highway Administration (FHWA) estimates that the bridge investment backlog (in dollar terms) would be reduced by 93% by 2030. Reducing the backlog to near zero during the same period is estimated to require an annual spending rate about 2% higher than the 2010 level.
MAP-21 eliminated the former Highway Bridge Program, which distributed federal money specifically for bridge improvements. States may use funds received under two major FHWA programs, the National Highway Performance Program and the Surface Transportation Program, for bridge repairs or construction, but the decision about how much of its funding to devote to bridges rather than roadway needs is up to each state. FHWA enforces certain planning requirements and performance standards established in MAP-21, but it does not make the determination as to which bridges should benefit from federal funding.
Congressional issues regarding the nation's highway bridge infrastructure include
Given the steady decline in the number of structurally deficient bridges during recent decades, should Congress accelerate work on the remaining deficient bridges? Should Congress encourage the states to spend more of their federal funds on their deficient bridges, potentially reducing the flexibility states were granted under MAP-21? Given large projected shortfalls in highway trust fund revenues relative to authorized spending, should Congress encourage increased use of tolling and public-private partnerships (P3s) to improve bridges? Should Congress redirect spending away from off-system bridges to more heavily used bridges on the designated federal-aid highways? Congressional oversight of bridge conditions could be complicated by the absence of a freestanding program. How quickly can FHWA develop the MAP-21 performance measures to report to Congress on progress on bridge conditions?
A brief CRS video on this subject may be viewed at http://www.crs.gov/video/detail.aspx?PRODCODE=WVB00009&Source=search.