Tennessee Code Title 54. Highways, Bridges and Ferries § 54-1-101

(1) Cause to be made and kept blueprints and maps showing a general highway plan of the state; the plan to consist of the main traveled roads that will, when improved, show and provide a connected system of improved highways throughout the state;

(2) Collect information and statistics with reference to the mileage, character, and condition of highways and bridges in the counties;

(3) Investigate and determine the method of road construction best adapted to the various sections; and

(4) Establish standards for the construction and maintenance of highways in the counties, giving due regard to topography, natural conditions, availability of road material, prevailing traffic conditions, and ways and means of the counties to meet their portion of the cost of building and maintaining roads under this chapter and chapters 2 and 5 of this title.