Tenn. Code Ann. § 54-11-222: Joint county and city bridges authorized - Terms - Toll or free

(a) The county, acting through the county legislative body, has the power to unite with any municipal corporation in the erection and regulation of bridges for public travel and traffic, over any stream, running by or through the municipality, upon terms agreed upon by the county and municipality erecting the bridges.

(b) The bridges may be toll or free, and may be changed from toll to free, or from free to toll bridges, from time to time, by the joint action of the county and municipality interested.