Tenn. Code Ann. § 4-3-2007

Subject to the approval of the department of general services under the authority of § 4-3-1105(9), the department of safety shall develop rules and regulations for the acquisition, assignment, use and disposal of motor vehicles. Such rules and regulations should promote the efficient and effective use of motor vehicles in law enforcement activities. These rules and regulations are also subject to approval by the department of finance and administration.