“Chauffeur” means every person who is employed for the principal purpose of operating a motor vehicle and every person who drives a motor vehicle while in use as a public or common carrier of persons or property except a person who operates a motor vehicle as a public or common carrier of persons over a regular route on a fixed schedule within the limits of any city or town or over a regular route on a fixed schedule between cities and towns where the boundaries between them are not more distant than five (5) miles.