Tenn. Code Ann. § 55-1-125

“Medium speed vehicle” means any four-wheeled electric or gasoline-powered vehicle, excluding golf carts, whose top speed is greater than thirty miles per hour (30 mph), but whose maximum speed allowed is thirty-five miles per hour (35 mph) only on streets with a forty mile per hour (40 mph) or less posted speed limit pursuant to § 55-8-191(b)(1), including neighborhood electric vehicles and mini-trucks. Medium speed vehicles must meet or exceed the federal safety standards set forth in 49 CFR 571.500, except as otherwise provided in § 55-4-136.