No person not of the department shall erect a sign of any character upon the right-of-way of any street, road, or highway, outside of incorporated municipalities, designated by the department as a main traveled road and included in the general highway plan of the state.
Signs not to be erected along highways designated as main traveled roads
Tenn. Code Ann. § 54-5-703, under Directional Signs.
Tenn. Code Ann. § 54-5-703