Tenn. Code Ann. § 54-4-601: Eligibility

(a) Eligible bridges shall be those located on public roads under the jurisdiction of a local government, and shall not include bridges located on the state system of highways. Any local government that meets the eligibility requirements in § 54-4-504(c) shall be eligible for participation in the high priority bridge replacement program.

(b) For purposes of this part, "bridge" means a structure on a public road, including supports, erected for carrying traffic over a depression or an obstruction, such as water or a highway or railway, and having an opening measured along the center of the roadway of more than twenty feet (20') between under-copings of abutments or spring lines of arches, or extreme ends of openings for multiple boxes; it may also include multiple pipes, where the clear distance between openings is less than half of the smaller contiguous opening.