So far as practicable, all traffic control signs, signals and devices required hereunder for a particular purpose shall be uniform as to type and location throughout the City and shall conform to the uniform state standards for traffic devices. No traffic control signal or device shall 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 unless first approved by the state highway commission. 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. 304 § 27, 1963).