A new study finds that 260 million people a day cross bridges in the USA that are structurally deficient. 
 
 A collapsed section of the Interstate 5 bridge over the Skagit River is seen in an aerial view on May 24 in Mount Vernon, Wash. (Photo: Mike Siegel, AP) Story Highlights Federal Highway Administration estimates repairs would cost $76 billion 
 
 Average age of the structurally deficient bridges is 65 years old 
 
 One expert says: 'We've never had a better bridge system" 
 
 More than one in nine bridges in the USA — at least 66,405, or 11% of the total — are structurally deficient, according to a new report. 
 
 These are not rarely used, out-of-the way structures: Each day, Americans take 260 million trips over structurally deficient bridges, says the report from Transportation for America, a Washington, D.C.-based coalition that works to improve transportation. 
 
 The report comes less than a month after the May 23 collapse of a span of the Interstate 5 bridge over the Skagit River in Washington state. Part of the bridge collapsed when it was struck by a truck with an oversize load. That bridge, built in 1955, was not structurally deficient. 
 
 The structurally deficient bridges are 65 years old on average, and the Federal Highway Administration estimates that repairing them would cost $76 billion. 
 
 A structurally deficient bridge isn't necessarily one that's dangerous or about to collapse; rather, they are bridges that require significant maintenance, rehabilitation or replacement. 
 
 A truck is removed May 27 from the wreckage of an Interstate 5 bridge over the Skagit River in Mount Vernon, Wash. That bridge, which was built in 1955 and collapsed May 23, was not structurally deficient. (Photo: Washington State Department of Transportation via AP) 
 
 The repair bill will likely increase as many of the nation's most heavily traveled bridges, including those built as part of the interstate system, near the end of their expected life spans. "You're seeing the aging of the system," says David Goldberg, a co-author of the report. "It really does parallel the (aging of) the Baby Boomers in a startling way." 
 
 This is a problem that has worsened since Transportation for America's last report on bridges, in 2011: Fifteen states have seen an increase in their structurally deficient bridges. The report projects that in 10 years, one in four bridges will be 65 years old or older. 
 
 In the two-year federal transportation funding bill it passed last year, Congress eliminated a dedicated fund for bridge repair. "The upshot is that bridge repair now must compete with other transportation needs," the report says. Money previously targeted for bridge repair was rolled into a new National Highway Performance Program, which can be spent only on highways that are part of the National Highway System, which includes interstates and major state highways. Nearly 90% of structurally deficient bridges are not part of the National Highway System. 
 
 Transportation for America recommends that Congress raise new dedicated revenues for transportation programs including bridges; that 180,000 bridges be made eligible for the new funding program, and that repair of bridges and highways be made a national priority. 
 
 Not everyone is alarmed over the state of the nation's bridges. "From my perspective, we've never had a better bridge system than we have right now," says David Hartgen, senior fellow at the libertarian Reason Foundation who co-authored a February report on the condition of roads and bridges in the USA. "The overall system is getting better slowly and steadily over time" as states work to improve their roads and bridges. 
 
 Hartgen, emeritus professor of transportation studies at the University of North Carolina at Charlotte, says it's good that more responsibility for repairing bridges is shifted from the federal government to the states. "The states are closer to the problem," he says. "I'm not overly pessimistic about the funding picture. At the state level, there is more willingness to raise state taxes for bridges." 
 
 Read or Share this story: http://usat.ly/11XSsQ1 ||||| Elaine Thompson / AP The north end of the Interstate 5 bridge crossing the Skagit River lies collapsed in the water on Friday, in Mount Vernon, Wash. A truck carrying an oversize load struck the four-lane bridge on the major thoroughfare between Seattle and Canada, sending a section of the span and two vehicles into the Skagit River below Thursday evening. All three occupants suffered only minor injuries. At an overnight news conference, Washington State Patrol Chief John Batiste blamed the collapse on a tractor-trailer carrying a tall load that hit an upper part of the span. 
 
 The Washington state bridge collapse that spilled two cars into the Skagit River could give Americans pause as they hit the roads for Memorial Day holiday travel. 
 
 With good reason. 
 
 This weekend, millions will cross 66,000 bridges that the federal government has deemed "structurally deficient," meaning key elements are in poor condition. 
 
 The Federal Highway Administration hastens to note that label doesn't mean they are unsafe or in danger of collapse, but transportation advocates say it highlights a growing crisis of aging infrastructure, deferred maintenance and rebuilding, and design flaws. 
 
 "We don't expect an epidemic of collapses — that's the extreme," said Dan Goldberg, communications director for Transportation for America, a coalition that identified the busiest deficient bridges in the nation in a 2011 report. 
 
 "We are going to see probably some more of this, but the more likely scenario is contending with the issues of decay that happen before the collapse." 
 
 Big potholes, weight restrictions and lane closings are some of the inconveniences bridge users face unless reconstruction and replacement is ramped up across the nation, Goldberg said. 
 
 The Interstate 5 bridge in Mount Vernon, Wash., which apparently crumpled after being hit by an oversized truck, was not on the Federal Highway Administration's structurally-deficient list. 
 
 Famed spans aren't the problem. San Francisco's Golden Gate, for instance, is in pretty good shape. The Brooklyn Bridge is undergoing a massive rehabilitation project to correct its deficiencies. 
 
 But hundreds of less glamorous bridges — many of them generic overpasses that take commuters over cross streets or other highways — remain vulnerable. 
 
 Here are six crossings, together used by more than 1 million vehicles each day, that don't make the grade: 
 
 Maryland DOT A view of I-695 crossing over Liberty Road in Maryland in August 2012. 
 
 I-76 over Klemm Ave. in Gloucester, N.J.: The deck and superstructure are in poor condition on this 11-lane interstate overpass that dates to 1956. More than 191,000 vehicles use it every day, and $30 million has been earmarked for deck replacement. 
 
 IS-695 over Milford Mill Road in Baltimore, Md.: Built in 1961 and reconstructed in 1979, this eight-lane overpass on the Baltimore Beltway has a deck and substructure in poor condition. But good news for nearly 190,000 vehicles that cross each day: It will be replaced in a two-year project starting this summer. 
 
 Halona St. Bridge in Honolulu, Hawaii: Built in 1938, this slab bridge over the Kapalama Canal is not slated for replacement until 2019. Some 184,000 vehicles travel the two-lane crossing, which has a deck and substructure in poor condition. 
 
 Colorado DOT A view of the I-70 bridge over Havana Street in Denver, Colo. E-17-JP 
 
 I-70 over Havana St. in Denver, Colo.: This 10-lane structure, which has a deck and substructure in poor condition, is slated for a rebuild in the next few years. Built in 1964 and reconstructed in 1978, it services 183,000 vehicles a day. 
 
 I-278 approach to the Verrazano-Narrows Bridge in Staten Island, N.Y.: On an average day, 182,700 vehicles take this overpass to a majestic double-decker bridge. The substructure of the two-lane approach, built in 1961, is in poor condition. 
 
 I-95 over Hendricks Ave. in Jacksonville, Fla.: The deck is in poor condition on this nine-lane section of interstate that handles 121,000 vehicles a day. Built in 1959 and reconstructed in 1989, it is undergoing a replacement. 
 
 Source: Information about the structures was compiled by Nationalbridges.com, a website that analyzes data in the Federal Highway Administration's national bridge inventory. ||||| Visualizing the numbers 
 
 Did you know that in another ten years, one in four bridges will be 65 years old or older? And today, almost 50 percent of bridges of that age are structurally deficient? 
 
 In the minute it’ll take you to view this full infographic with more facts like that, another 180,000 trips will be taken on deficient bridges. Click to see the whole graphic, learn more, and share it with your friends. 
 
 Click for more details about the data.
– If this story didn't already cause you to develop a mild case of gephyrophobia, then this one may do the trick: Some 11% of America's bridges are structurally deficient and in need of repair, according to a new report from Transportation for America. It's a stat made more serious when you consider this next one: 260 million trips are made across the 66,405 problematic bridges each day. As USA Today explains, these bridges aren't necessarily dangerous, they just need a lot of work, which has been priced at $76 billion by the Federal Highway Administration. That amount will just get larger as the years pass. These bridges are, on average, 65 years old, and in 10 years, the number of "senior citizen" bridges will be one in four. "You're seeing the aging of the system," says a co-author of the report. "It really does parallel the [aging of] the Baby Boomers in a startling way." Congress recently eliminated a dedicated bridge repair fund, meaning "bridge repair now must compete with other transportation needs," the report states. Rather than "an epidemic of collapses," the more common consequences of the aging bridge system will be things like more large potholes and closed lanes, the co-author tells NBC News.