Federal programs for bridge construction, reconstruction, and repair are authorized in surface transportation acts. In 2012, MAP-21 consolidated a number of existing highway formula programs, including the Highway Bridge Program (HBP). Bridge projects are now generally funded through the National Highway Performance Program (NHPP) and the Surface Transportation Block Grant Program (STBGP). MAP-21 included a number of statutory requirements related to transforming the surface transportation system to a performance-based approach. For instance, MAP-21 directed DOT to establish performance measures related to highway safety, asset condition, and highway system performance, among other things. In some cases, MAP-21 required DOT to use the rulemaking process to implement performance-based requirements. In 2015, the Fixing America’s Surface Transportation Act (FAST Act), which reauthorized surface transportation programs, largely maintained current program structures, including MAP-21’s overall performance- management approach. The FAST Act also expanded the eligibility of NHPP funds to be used for reconstruction, resurfacing, restoration, rehabilitation, or preservation of a non-National Highway System (non- NHS) bridge if the bridge is on a Federal-aid highway. FHWA is the agency charged with oversight of the condition of the nation’s bridges. FHWA administers the federal-aid highway program that provides about $40 billion each year to states to design, construct, and preserve the nation’s roadway and bridge infrastructure. These funds are distributed through annual apportionments established by statutory formulas. FHWA oversees the federal-aid highway program primarily through its 52 Division Offices located in each state, D.C., and Puerto Rico. FHWA Division Offices have 10 to 61 staff each, depending on the size of the state’s highway program and other factors. As of June 2016, FHWA had approximately 2,800 staff—about two-thirds in the field and the remaining third at FHWA headquarters. FHWA distributes and tracks federal funds for highway and bridge projects and collects some data to estimate annual spending by state and local governments on highway and bridge projects. Specifically, FHWA tracks federal-aid highway program obligations in FMIS, for individual project segments or contracts. This allows FHWA to collect and report information on the types of activities (such as obligations for the construction of new bridges) funded with Highway Trust Fund monies. 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. State and local agencies typically provide matching funds on bridge projects that receive federal funding and may contribute funds beyond their match amount. State-level DOTs are responsible for ensuring bridge inspections are completed and for inventorying bridges within their states according to federal standards (except for tribally or federally owned bridges). State DOTs and local-planning organizations have discretion in determining how to allocate available federal funds among various projects and are responsible for selecting highway projects, including bridge projects. FHWA collects some data to estimate annual spending by state and local governments on highway and bridge projects. Specifically, FHWA requests that state DOTs submit several forms to the Office of Transportation Policy Studies on a regular basis, such as: Form 532, State Highway Expenditures—submitted annually, it requests the total spent on all highways by the state, including bridges; bridges are not separately reported. Form 536, Local Highway Finance Report—submitted biennially, it requests the total spent on all highways by all units of the state’s local governments. Bridges are not separately reported. Acknowledging difficulties in obtaining data from local agencies, FHWA recommends that states use sampling and estimation to prepare this form, such as collecting data from a selection of local governments and then expanding the sample to generate statewide totals. Form 534, State Highway Capital Outlay and Maintenance Expenditures—submitted annually, it requests bridge-specific and other highway outlays. This form is designed to complement the data in Form 532 by classifying the highway expenditures of states into improvement types, such as new construction and rehabilitation, among other things. As part of its oversight role, FHWA collects information from states on bridge conditions and maintains this data in its NBI database. Bridges that receive low inspection ratings on specific bridge elements are classified as deficient. Bridges may be classified as deficient for one of two reasons: A structurally deficient bridge has one or more structural components, such as the deck that directly carries vehicles, in poor condition. Structurally deficient bridges often require maintenance and repair to remain in service. A functionally obsolete bridge has a configuration or design that may no longer be adequate for the traffic it serves, such as being too narrow or having inadequate overhead clearance. Functionally obsolete bridges do not necessarily require repair to remain in service. A bridge that is both structurally deficient and functionally obsolete is listed as structurally deficient in the NBI. In this report, we assess the conditions of bridges classified as structurally deficient by both the total deck area and number of bridges. Analysis of conditions based on the total number of bridges without considering the size of bridges can create an incomplete picture. A state may have a large number of deficient bridges, but if the deficient bridges are small bridges, the total deck area in need could still be relatively low. In comparison, another state could have very few deficient bridges, but if those deficient bridges are large, the total deck area in need could be much higher. Bridges may vary significantly in size and generally, the needs of larger bridges are more costly than those of smaller bridges. Measuring the total deck area, which accounts for the size of a bridge, provides more information than counting the number of bridges (see fig. 1). We found that bridge conditions, as indicated by data in the NBI, have improved nationwide over the past 10 years, as measured by total deck area and number of bridges that are structurally deficient. 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. 2). Bridge owners have broad discretion in determining how to address bridge needs, but statutory requirements enacted in 2012 directed that states allocate some federal funds to bridges if states do not meet specified standards. FHWA does not issue guidance on which bridges to target with federal funds, such as specifically targeting structurally deficient bridges. However, MAP-21 contained a penalty provision where any state whose percentage of total deck area of bridges on the NHS classified as structurally deficient exceeds 10 percent for 3 years in a row must devote funds (equal to 50 percent of the state’s fiscal year 2009 HBP apportionment) to eligible projects on bridges on the NHS until they meet this minimum threshold. FHWA officials told us they plan to use bridge condition data from 2014 through 2016 to determine if a penalty is to be applied to the states, and begin imposing this penalty in 2017 if needed. Despite overall improvements, among states there is variation in bridge conditions. 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. 3). For example, 21 percent of the total deck area in Rhode Island, affecting 23 percent of the 766 bridges in the state, is structurally deficient. While in Texas, less than 2 percent of the total deck area, affecting less than 2 percent of the state’s 53,209 bridges, is structurally deficient. Most but not all states have made some improvements in reducing their percentage of deck area on bridges classified as structurally deficient over the past 10 years. Forty-one states, D.C., and Puerto Rico reduced the percentage from 2006 to 2015. Rhode Island had the greatest reduction, going from over 40 percent to over 20 percent of total deck area on bridges that are structurally deficient. However, in 9 states the percentage increased from 2006 to 2015. Delaware had the highest increase in the percentage of deck area on bridges classified as structurally deficient, going from 2 percent to almost 6 percent. GAO has reported that reducing structurally deficient bridges may not always be a state’s highest priority. For example, a state may have other priorities for bridge projects such as seismic retrofitting. According to AASHTO representatives, states use their judgment in deciding how to prioritize their funding for bridge projects. See appendix II for more information about the percentages of bridges and total deck area that are structurally deficient in each state. The number of bridges and amount of total deck area increased dramatically from the 1950s through 1970s. The average age of bridges nationwide is 45 years, based on our analysis of NBI data. According to FHWA, the design life of the majority of existing bridges is 50 years, though bridges have life spans that are dependent on factors such as materials, environment, level of use, and level of maintenance. Also according to FHWA, new design guidelines and construction materials may raise the expected service life of new bridges to 75 years or longer. However, states and other bridge owners are faced with significant challenges in addressing the needs of existing bridges. In the 1950s, at the beginning of the Interstate-era, through the 1970s, the number of bridges constructed in the United States as well as the total square footage of bridge deck constructed increased greatly (see fig. 4). Analysis of NBI data indicates that the large number of bridges built during that time has led to an increase in the need to address those bridges that are now structurally deficient. Specifically, as shown in figure 5, the levels of structurally deficient total deck area are greatest for those built from 1960 through 1974, during which years the total deck area of bridges built in the United States peaked.