It shall be unlawful for any unauthorized person to erect or display any device upon or in view of any highway, which device is an imitation of an official traffic sign, or which directs or purports to direct the action of operators of vehicles or the movement of traffic, or to wilfully deface, injure, move or interfere with any sign placed in compliance with the provisions of this chapter. (Ord. 77, 9-4-1973)