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Highway Bridges: Linking Funding to Conditions May Help Demonstrate Impact of Federal Investment

GAO-16-779 Published: Sep 14, 2016. Publicly Released: Sep 14, 2016.
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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.

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.


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.

Recommendations for Executive Action

Agency Affected Recommendation Status
Department of Transportation The Secretary of the Department of Transportation should 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.
Closed – Implemented
The Department of Transportation (DOT) administers the federal-aid highway program that supports the construction, maintenance, and preservation of the nation's highways and bridges. As part of its oversight role, DOT distributes and tracks federal funds for bridge projects and collects some data to estimate annual spending by state and local governments on such projects. DOT also collects information from states on bridge conditions and maintains this data in its national bridge database. In 2016, GAO reported that bridge conditions have improved nationwide from 2006 to 2015, by some measures. However, bridge conditions may become more challenging to address as bridges age, and the effects of expended resources are unclear. DOT currently lacks a mechanism for tracking the relationship between the invested funds and the corresponding outcomes-maintained and improved bridge conditions. According to leading practices for government management identified by OMB and GAO, agencies should not only have and report performance measures but also use them to link outcomes with resources invested. According to DOT officials, they had not developed measures linking resources to outcomes mostly due to limitations of the previous version of their financial tracking system, but that such a comparison could be possible with the newest version of this system by creating a connection between their financial tracking system and the national bridge database. Given that DOT already collects information on bridge conditions annually and maintains data on federal obligations dedicated to bridges, it has the information needed to create performance measures demonstrating the link between bridge funding and changes in bridge conditions. Therefore, GAO recommended that DOT 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 fiscal year 2020, GAO confirmed that DOT had developed an efficiency metric that incorporates bridge funding and improvement in bridge conditions. Specifically, the metric divides the fiscal year obligation by the percent improvement in bridge condition, based on area of bridges classified as in poor condition. DOT stated it will incorporate this metric into the next bridge safety report to Congress, which it expects to release by December 1, 2020. As a result of these efforts, DOT is in a better position to support Congress in making informed choices about how to best invest limited available resources in maintaining or improving the condition of the nation's bridges.

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BridgesData collectionFederal aid for highwaysFederal aid for transportationFederal fundsHighway researchPerformance measuresPublic roads or highwaysTransportation