It’s a mixed bag for the condition of U.S. bridges according to a new analysis of the U.S. DOT’s 2015 “National Bridge Inventory” database. The good news is there were 2,574 fewer structurally deficient bridges in 2015 compared to the number in 2014. The bad news is there are still 58,500 on the structurally deficient list—and at the current pace of bridge investment—it would take at least 21 years before they were all replaced or upgraded.
The American Road & Transportation Builders Association (ARTBA), which conducts the annual review of state bridge data collected by the federal agency, notes that if placed end-to-end, the deck surface of the nation’s structurally deficient bridges would stretch from New York City to Miami (1,340 miles).
About 9.5% of the nation’s approximately 610,000 bridges are classified as structurally deficient, ARTBA found, but cars, trucks, school buses and emergency vehicles cross these deficient structures nearly 204 million times a day.
To help ensure public safety, bridge decks and support structures are regularly inspected by the state transportation departments for deterioration and remedial action. They are rated on a scale of zero to nine—with nine meaning the bridge is in “excellent” condition. A bridge is classified as structurally deficient and in need of repair if its overall rating is four or below. Unfortunately, the funding made available to state and local transportation departments for bridge work is not keeping pace with needs.
While these bridges may not be imminently unsafe, the purpose of the report, the association said, is to help educate the public and policymakers that they have structural deficiencies that need repair.
Almost all of the 250 most heavily crossed structurally deficient bridges are on urban highways, particularly in California. Nearly 85% were built before 1970.
Iowa (5,025), Pennsylvania (4,783), Oklahoma (3,776), Missouri (3,222), Nebraska (2,474), Kansas (2,303), Illinois (2,244), Mississippi (2,184), North Carolina (2,085) and California (2,009) have the most structurally deficient bridges, the analysis found. The District of Columbia (10), Nevada (35), Delaware (48), Hawaii (60) and Utah (95) have the least.
At least 15% of the bridges in eight states—Rhode Island (23 percent), Pennsylvania (21%), Iowa (21%), South Dakota (20%), Oklahoma (16%), Nebraska (16%), North Dakota (16%) and West Virginia (15%)—fall in the structurally deficient category.