Tenn. Code Ann. § 54-5-101: System of state highways - Designation by department for construction, repair or maintenance

The department of transportation has full power, and it is made its duty, through its highway engineers or otherwise, to designate a system of state highways, to designate the road or roads to be constructed, repaired, or maintained by the use of the funds mentioned in chapter 2 of this title, and to lay out and locate all such roads.