There are 19,519 bridges on public roads in the state of Tennessee. These bridges fall into two categories for the purpose of distributing state and federal funds. On-System Bridges are those maintained, owned and operated by the state. They are found on the Interstate System, the National Highway System and the State Route System and include 8,113 bridges. Off-System Bridges are those found on roads owned, maintained and operated by local governments that include counties, cities and towns in Tennessee. Those number 11,406.
Tennessee has been working steadily to improve the conditions of its bridges, both on and off-system for the last two decades. A statistical overview of how we have progressed since 1982 demonstrates our success since that year.
- The total number of bridges for on-system has increased by 2,753 or 50%, yet the following has also occurred.
- The number of posted bridges (those carrying less than 15 ton loads) has decreased by 91.8%
- The number of structurally deficient bridges has decreased 57.4%
- The number of functionally obsolete (not containing enough traffic lanes for the amount of traffic crossing the bridge) has increased by only 17.3%. This reflects an aging bridge population, and ever increasing traffic.
- The total number of bridges on off-system routes has declined by 6.5%, but
- The number of posted bridges has declined 82.8%
- The number of structurally deficient bridges has decreased by 89.1%
- The number of functionally obsolete bridges has decreased by 23.3%
Current Bridge Status
- The number of bridges carried as structurally deficient is 337 (4.2%) of the bridge population.
- Functionally obsolete bridges are 1,223 (15.1%) of the population.
- There are no bridges on the state system that require posting, which are not already posted.
- There are only 2 closed on-system bridges. These bridges are currently under construction and are closed for that reason.
- The number of bridges deemed structurally deficient is 856 (7.5%) of the bridge population.
- Functionally obsolete bridges number 1,719 (15.1%)
- There are 46 off-system bridges on which TDOT has recommended closure to the owner. Of these, only 3 to date have not been closed. However, these 3 represent only 1/38 of one percent (.00026) of the off-system bridge population.
- Of those off-system bridges requiring posting, only 37 of 1,010 are not. This represents 3.7% of bridges not properly posted. This comprises only 0.32% of all off-system bridges.
Between 1982 and 2007 under the federal bridge replacement program TDOT spent $1,457,000,000 and, on the state grant bridge program, TDOT spent an additional $261,000,000. This totals over $1.7 billion in money spent on bridges in the last 23 years.