Our Nation's Highways: 2008

Figure 7-4. Bridge Conditions, 1991-2007

The National Bridge Inventory data documents the conditions of bridges on all public roads, regardless of their ownership. Bridges are evaluated and rated as “not deficient,” “functionally obsolete,” or “structurally deficient.” A bridge rated “functionally obsolete” is not unsafe for all vehicles. Rather, it typically has an older design that lacks modern safety features such as adequate shoulder space, an appropriate railing system, or other features. A bridge rated “structurally deficient” is not necessarily unsafe either. Strict observance of signs limiting traffic or speed on the bridge will generally provide adequate safeguards for those who use the bridge.

As shown in Figure 7-4, the number of structurally deficient bridges has been declining since 1992. The number of functionally obsolete bridges has stayed relatively constant since 1992. As of December 2007, of the 599,766 bridges in the United States, 72,524 bridges were structurally obsolete and 79,792 were functionally obsolete.

Data represented in the inset chart
Table in Excel format

Data Source: U.S. Department of Transportation, Federal Highway Administration, Office of Bridge Technology, National Bridge Inventory.