No person shall place, maintain or display upon or in view of any highway, street or alley any unauthorized sign, signal, marking or other device which purports to be or is an imitation of or resembles an official parking sign, curb, marking or traffic control device or railroad sign or signal or which attempts to direct the movement of traffic or which hides from view or interferes with the effectiveness of any official traffic control device or any railroad sign or signal. No person shall place or maintain upon any highway or street or alley any traffic sign or signal bearing thereon any commercial advertising. This section shall not be deemed to prohibit the placement upon private property adjacent to highways any signs giving useful directional information of a type that cannot be mistaken for official signs and subject to the zoning laws as provided in the ordinances of the city. (1978 Code §23-35; amd. 1994 Code)