Almost 56,000 U.S. bridges are 'structurally deficient.' Is one near you on the list?

FILE - This Sept. 11, 2013, file photo shows the bridge on Western Avenue over the Cal-Sag Channel framed by the rusted supports of the closed Chatham St. bridge in Blue Island, Ill. The Western Avenue bridge was classified as both "structurally deficient" and "fracture critical" in federal data for 2012. An analysis of Transportation Department data released by the American Road & Transportation Builders Association on Feb. 15, 2017, says more than 55,000 bridges in the U.S. have been deemed structurally deficient. (AP Photo/M. Spencer Green, File)

FILE - This Sept. 11, 2013, file photo shows the bridge on Western Avenue over the Cal-Sag Channel framed by the rusted supports of the closed Chatham St. bridge in Blue Island, Ill. The Western Avenue bridge was classified as both "structurally deficient" and "fracture critical" in federal data for 2012. An analysis of Transportation Department data released by the American Road & Transportation Builders Association on Feb. 15, 2017, says more than 55,000 bridges in the U.S. have been deemed structurally deficient. (AP Photo/M. Spencer Green, File)

A study released Wednesday warns that nearly 56,000 bridges across the United States are structurally deficient.

The study, by the American Road and Transportation Builders Association, lists 55,710 “deficient” bridges used by more than 185 million drivers a day.

According to the study, one quarter of the bridges listed are at least 50 years old, and have never undergone any reconstruction.

Bridges that have been labeled structurally deficient aren't necessarily in immediate danger of collapse, the study pointed out. The term “structurally deficient” means that the bridges need rehabilitation or replacement because at least one major component has deteriorated or because the bridge has other problems.

The study listed problem bridges in every state. Iowa has the largest number of structurally deficient bridges at nearly 5,000. The top 14 most-traveled deficient bridges are located in California.