One of the statewide programs funded by TDOT is the Federal-Aid Bridge
Following the collapse of a major bridge over the Ohio River on December 15, 1967, with the loss of 46 lives, Congress enacted legislation that laid the framework for a National Bridge Inspection Program. This was accomplished primarily by the Highway Acts of 1968 and 1970. The funding program was designated as the Highway Bridge Rehabilitation and Replacement Program (HBRRP).
In order for bridges to be replaced in a systematic and prioritized manner, the condition of the nationís bridges had to be ascertained. Hardly any states, Tennessee included, had any kind of formal bridge inspection program, nor did they possess detailed bridge records. Therefore, the first step to determine the nationís needs was to establish and fund the National Bridge Inspection Standards (NBIS).
Funding under the HBRRP was initially focused on Federal Aid Routes (System Bridges). With the 1978 Surface Transportation Act, HBRRP funding was extended to cover the inspection and replacement of locally owned (off-system) bridges. Provisions in the act established that 15 to 35 percent of HBRRP funds would be spent on off-system bridges, as determined by the individual states. Since almost 60 percent of the highway bridge inventory in Tennessee is classified as off-system and since the off-system inventory contains a disproportionately larger percentage of deficient bridges, TDOT initially set aside the maximum of 35 percent of HBRRP funding for off-system bridges. In more recent years, local Governments have been reluctant to accept offers of bridge replacement funding due to fiscal restraints. Under the HBRRP, the Federal Government pays 80 percent of the cost for a project with the bridge owner providing the remaining 20 percent as matching funds. Currently TDOT sets aside 20 percent of available HBRRP funds for off-system bridges. This seems adequate to meet current demands.
Since the beginning of the Bridge Replacement Program in Tennessee, over $1.5 billion has been spent to replace or rehabilitate bridges on public roads in Tennessee, and the HBRRP continues to represent a significant part of TDOTís annual budget.
This graph indicates progressive reductions in deficient and obsolete bridges over time. This data is courtesy of the Federal Highway Administration.