Federal law mandates the uniform inspection of all bridges for structural adequacy at least every two years; bridges rated “deficient” are eligible for federal repair dollars. Table 16 and Figure 11 of this analysis use the National Bridge Inventory (NBI) as the source of the bridge data, which is provided in summary form in Better Roads (see Appendix). Since the NBI contains some recent inspections and some as old as two years, the age of the “average” inspection is about one year. So, a “December 2020” summary from the NBI would represent, on average, bridge condition as of December 2019.
The condition of the nation’s highway bridges in 2021 improved slightly from 2020, the last time this assessment was completed. Of the 617,008 highway bridges reported, 43,289 (7.02%) were rated structurally deficient for 2021 (Table 16, Percent of Structurally Deficient Bridges, 2021, Figure 11). This represents a 0.44% improvement over 2020 when 45,861 of 614,490 (7.46%) were rated as structurally deficient.
Arizona, Nevada, Texas, and Delaware reported less than 2% of their bridges as structurally deficient (1.38%, 1.40%, 1.43%, and 1.94% respectively). West Virginia reported more than 20% of its bridges as structurally deficient (at 20.37%). The majority of states (39) reported at least some improvement in the percentage of structurally deficient bridges between 2020 and 2021, with Rhode Island and South Carolina seeing the most improvement (4.88 and 3.13 percentage points, respectively). Of the 11 states that reported a higher percentage of deficient bridges, none saw an increase of more than one percentage point.
Structurally Deficient Bridges — Percent Deficient
|2021 Rank||State||Percent Structurally Deficient Bridges|