Tenn. Code Ann. § 55-52-104

The purpose of this part is to reduce the incidence of disability and death resulting from injuries incurred in bicycling accidents by requiring that, while riding on a bicycle on state highways, streets and sidewalks, all bicycle operators and passengers under sixteen (16) years of age wear approved protective bicycle helmets; that all bicycle passengers who weigh less than forty pounds (40 lbs.) or who are less than forty inches (40") in height be seated in separate restraining seats; and that no person who is unable to maintain an erect, seated position shall be a passenger in a bicycle restraining seat.