There are 185 million daily crossings on nearly 56,000 structurally deficient U.S. bridges. Image Credit: U.S. Department of Transportation

The 2016 National Bridge Inventory recently released by the U.S. Department of Transportation indicates that more than 55,000 bridges in the nation are structurally deficient.

Analysis of the inventory data by the American Road & Transportation Builders Association (ARTBA) concludes that 28% of bridges (173,919) are over 50 years old and have never had any major reconstruction work in that time. The inventory of structurally deficient bridges has declined 0.5% since the 2015 report. At that pace, it would take more than two decades to replace or repair all of them.

The most structurally deficient bridges are located in Iowa (4,968), Pennsylvania (4,506), Oklahoma (3,460), Missouri (3,195), Nebraska (2,361), Illinois (2,243), Kansas (2,151), Mississippi (2,098), Ohio (1,942) and New York (1,928).