Tenn. Code Ann. § 54-5-102: Main traveled roads - Designation

(a) The commissioner is given the power to proceed to designate main traveled roads, with a view to connecting all county seats, and also to designate other main traveled roads, that are deemed of sufficient importance to be included in the general highway plan of the state, and receive for their construction and improvement financial aid under this chapter and chapters 1 and 2 of this title.

(b) It is the intent of the general assembly that all county seats should be connected by a four-lane highway to the nearest interstate highway by the best route available.