Although federal funding is provided to states to help improve highway  infrastructure, state and local agencies own and maintain most of the  nation’s bridges. The percentage  of structurally deficient deck area and bridges declined along the same  trajectory from 2006 to 2015. Specifically, the deck area on bridges  classified as structurally deficient decreased from 9 percent to 7 percent,  and over the same time period, structurally deficient bridges, by number  of bridges, decreased from 13 percent to 10 percent (see fig. Specifically, our review of 2015 NBI data shows that some  states have substantially higher percentages of deck area on bridges  classified as structurally deficient than others have (see fig. Bridge Conditions May Become More Challenging to Address as Bridges Age

The number of bridges and amount of total deck area increased  dramatically from the 1950s through 1970s. Federal Bridge Funding has Been Stable in the Last 10 Years, but the Effects of Expended Resources Are Unclear

		Federal Funds Obligated for Bridge Projects Have Generally Remained Stable

Federal funds obligated for bridges have remained relatively stable over  the last 10 years, between $6 billion and $7 billion annually in most years  (see table 1). In the last 10 years, federal obligations have shifted somewhat from  building new bridges to projects that preserve existing bridges. Given that FHWA already  estimates total funds dedicated to bridges and collects data on bridge  conditions nationwide, it has the information needed to create  performance measures that would demonstrate the link between federal  funding and the outcomes for bridges. We have reported that linking performance outcomes with  information on resources invested (i.e., data on the resources used to  produce an outcome, including costs) can help agencies to more clearly  understand how changes in invested resources may result in changes to  performance. Using such performance measures would help FHWA to  demonstrate the link between federal funding and outcomes for bridges. Selected States Reported Little Change in the Way They Fund and Manage Highway Bridges, and Identified Various Challenges Related to Funding and Aging Bridges

		Selected States Reported That Bridge Funding Has Generally Not Changed but That Flexibility of Funding Has Increased

Most of the state government officials we interviewed reported that,  consistent with FHWA data, bridge funding has been stable since the  federal bridge program was consolidated into other programs in 2012. We  interviewed officials from 24 states and D.C., and officials from 21 states  and D.C. told us there had been no change in funding their bridge  programs in the last 4 years. Officials from 3 states reported an overall  increase in bridge funding since that time, although officials from 2 of  those states indicated that the increase in bridge funding was not  necessarily a result of federal changes. The general stability in bridge funding may be a result of the long time  frame for programming bridge projects, which could create a lag in  funding levels’ response to policy changes. Officials from some selected states reported increased flexibility in their  ability to use federal funds for bridges. In addition to allowing states the  flexibility to determine whether to spend federal highway funds on bridges  or other highway needs, changes provided by MAP-21 gave states  flexibility to use federal funds for a greater range of bridge projects. Specifically,  officials from 18 states and D.C. reported that they give bridges the same  priority as they did prior to MAP-21. Of the  officials we interviewed from 24 states and D.C., officials from 14  described inadequate funding as a challenge. Officials  from 13 of the states we interviewed reported aging bridges as a  challenge. For many of these states, the challenge of aging bridges is  intertwined with the challenge of inadequate funds. Recommendation for Executive Action

We recommend that the Secretary of the Department of Transportation  direct the FHWA Administrator to develop an efficiency measure or  measures that demonstrate the linkage between the federal funding of  bridges and the desired performance outcomes, such as maintained or  improved bridge conditions, and report the resulting information to  Congress. In addition, DOT provided technical comments that we  incorporated as appropriate. Appendix I: Objectives, Scope, and Methodology

This report addresses the funding and management of bridges and  examines: (1) trends, over the past 10 years, in the condition of the  nation’s bridges; (2) trends, over the same period, in federal funding of  the nation’s bridges and how FHWA monitors the linkage between this  funding and outcomes; and (3) changes since MAP-21 in how selected  states fund and manage their bridge programs, including any challenges  they face.
Why GAO Did This Study

The nation's 612,000 bridges are critical elements of the surface transportation system, but the entire system is under growing strain and funding it is on GAO's High Risk List. While state and local governments own and maintain most of the nation's bridges, the federal government provides some funding for them, administered by FHWA. In 2012, legislative changes consolidated the bridge-funding program into other highway programs, giving states more flexibility in how to allocate funds.
GAO was asked to review the funding and management of bridges. This report examines trends, over the past 10 years, in (1) the condition and (2) the funding of the nation's bridges, as well as (3) how states fund and manage their bridge programs, given the 2012 legislative changes. GAO analyzed FHWA's bridge conditions and funding data; reviewed applicable laws, relevant FHWA program guidance, and federal guidance on performance measures; and interviewed federal officials and transportation officials from 24 states and D.C., selected to include those with large bridge inventories, among other factors.

What GAO Found

Bridge conditions have generally improved nationwide from 2006 to 2015, based on GAO analysis of federal bridge data. For example, the percentage of structurally deficient bridge deck area (the surface area that carries vehicles) decreased from 9 percent to 7 percent nationwide during this period. The number of structurally deficient bridges also decreased from 13 percent to 10 percent nationwide. However, some states have substantially higher percentages of structurally deficient deck area than others. Bridge conditions may become more challenging to address as bridges age, because the number of bridges and amount of total deck area increased dramatically from the 1950s through the 1970s, generally with a 50-year design life. Analysis of federal bridge data shows that the amount of structurally deficient deck area is greatest for bridges built from 1960 through 1974, indicating an expected need for additional maintenance, replacement, or rehabilitation.
Federal funds obligated for bridge projects have remained relatively stable from 2006 to 2015, between $6 billion and $7 billion annually in most years. During this period, the use of federal funds on bridges shifted somewhat from building new bridges to projects that preserve existing bridges, such as bridge rehabilitation or preventative maintenance. While the Federal Highway Administration (FHWA) estimates total funds dedicated to bridges and collects data on bridge conditions nationwide, it does not track the linkage between federal funds and changes in bridge conditions. GAO has previously reported that linking performance outcomes with resources invested can help agencies to more clearly determine how changes in invested resources may result in changes to performance. Using such performance measures would help FHWA demonstrate the link between federal funding and outcomes for bridges.
Officials from the selected 24 states and the District of Columbia (D.C.) reported little change in the way they have funded and managed bridges since 2012. Officials from 21 states and D.C. reported bridge funding has been stable since the federal bridge program was consolidated in 2012. Officials from 3 states reported an increase in bridge funding since that time. The general stability in bridge funding may be a result of the long time frame for planning bridge projects; for example, bridge funding cycles can be 5 years or longer, a time span that means any changes would not be apparent for several years. Officials from 10 states mentioned increased flexibility in their ability to use federal funds for bridge projects. Changes from the Moving Ahead for Progress in the 21st Century Act provided states flexibility to determine whether to spend federal highway funds on bridges or other highway needs. Further, officials from 18 states and D.C. reported that they have not changed how they prioritize bridge projects relative to other transportation projects. With respect to challenges, officials from 14 states described inadequate funding as a challenge, and officials from 13 states reported aging bridges as a challenge. For many of these states, the challenge of maintaining aging bridges is intertwined with the challenge of inadequate funds.

What GAO Recommends

GAO recommends that DOT direct FHWA to develop measures on the linkage between the federal funding of bridges and the desired outcomes—maintained or improved bridge conditions—and report results to Congress. DOT concurred with our recommendation. DOT also provided technical comments, which we incorporated, as appropriate.