By JOAN LOWY and MIKE BAKERWASHINGTON (AP) â¿¿ Motorists coming off the Frederick Douglass Memorial Bridge into Washington are treated to a postcard-perfect view of the U.S. Capitol. The bridge itself, however, is about as ugly as it gets: The steel underpinnings have thinned since the structure was built in 1950, and the span is pocked with rust and crumbling concrete. District of Columbia officials were so worried about a catastrophic failure that they shored up the horizontal beams to prevent the bridge from falling into the Anacostia River. And safety concerns about the Douglass bridge, which is used by more than 70,000 vehicles daily, are far from unique. An Associated Press analysis of 607,380 bridges in the most recent federal National Bridge Inventory showed that 65,605 were classified as "structurally deficient" and 20,808 as "fracture critical." Of those, 7,795 were both â¿¿ a combination of red flags that experts say indicate significant disrepair and similar risk of collapse. A bridge is deemed fracture critical when it doesn't have redundant protections and is at risk of collapse if a single, vital component fails. A bridge is structurally deficient when it is in need of rehabilitation or replacement because at least one major component of the span has advanced deterioration or other problems that lead inspectors to deem its condition poor or worse. Engineers say the bridges are safe. And despite the ominous sounding classifications, officials say that even bridges that are structurally deficient or fracture critical are not about to collapse. The AP zeroed in on the Douglass bridge and others that fit both criteria â¿¿ structurally deficient and fracture critical. Together, they carry more than 29 million drivers a day, and many were built more than 60 years ago. Those bridges are located in all 50 states, plus Puerto Rico and the District of Columbia, and include the Brooklyn Bridge in New York, a bridge on the New Jersey highway that leads to the Lincoln Tunnel, and the Main Avenue Bridge in Cleveland.