Nearly 56,000 bridges in the U.S. are “structurally deficient,” a new report finds.

The bridges are traversed an estimated 185 million times daily. Among the highest- profile “deficient” bridges are New York City’s Brooklyn Bridge and the Arlington Memorial Bridge in Washington, D.C.

“Structurally deficient” doesn’t necessarily mean the bridges are unsafe, but that they need attention. To earn the rating, one or more key bridge elements ― such as the deck, superstructure or substructure — must be in “poor” or worse condition, according to the report.

“Just because a bridge is classified as structurally deficient doesn’t mean that it’s unsafe to drive on,” Peter Jones with Caltrans in California told ABC-7 News. “Those roads are perfectly safe.”

The 14 most-traveled deficient bridges are in California, and 10 of those are in Los Angeles, notes The Associated Press.

The study was conducted by the American Road and Transportation Builders Association, which has a vested interested in fixing up spans, but the findings are based on data from the Department of Transportation.

Almost 174,000 bridges (more than 1 out of 4 of all the bridges in America) are at least 50 years old and have never had major reconstruction work. Some 1,900 of the structurally deficients bridge are on interstate highways, the study found.

Iowa, Pennsylvania, Missouri, Oklahoma and Nebraska have the highest number of bridges with problems, according to the report. States with some of the highest percentages of structurally deficient bridges include Rhode Island (25 percent), Pennsylvania (21 percent), and Iowa and South Dakota (20 percent).

Six percent of the bridges in Minnesota are structurally deficient. In 2007 bridge collapse in Minneapolis killed 13 people dead and injured dozens of others.

The news comes just as dams are giving Americans the jitters after a rupture in the spillway at Oroville Lake in Northern California forced the evacuation of some 200,000 people. Other California dams are in trouble as are other systems in the U.S. The nation’s aging dams, most of them a half-century old, has earned a “D” from the American Society of Civil Engineers.

President Donald Trump has proposed a $1 trillion infrastructure program for the next decade, but the source of funding hasn’t been identified. He also needs $21.6 billion to build a wall along the border with Mexico.

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