All traffic-control signals, signs, and traffic-control devices to be erected or maintained upon any city street designated as forming a part of the route of a primary state highway or secondary state highway must be approved by the State Highway Commission prior to their installation. All signs and signals required hereunder for a particular purpose shall so far as practicable be uniform as to type and location throughout the city. All traffic-control devices so erected and not inconsistent with the provisions of state law or this title shall be official traffic-control devices. (Ord. 282 § 14, 1968).