Tennessee Code Title 68. Health, Safety and Environmental Protection § 68-140-326

(a) Notwithstanding department of health rule 1200-12-1.02(3)(a)-(f), or any other provision of law to the contrary, any municipality, located within any county having a population of more than eight hundred thousand (800,000), according to the 2000 federal census or any subsequent federal census, that owns, operates or maintains ambulances as a part of the services provided by the municipality is authorized to select the color of its ambulances; provided, that the color scheme is the same as is used by the fire department in the municipality.

(b) Subsection (a) shall also apply in any county having a metropolitan form of government and a population in excess of five hundred thousand (500,000), according to the 2000 federal census or any subsequent federal census.

(c) Subsection (a) shall also apply in any county having a population of not less than one hundred fifty-three thousand (153,000) nor more than one hundred fifty-three thousand one hundred (153,100), according to the 2000 federal census or any subsequent federal census.