A. The traffic authority shall have the power and duty to place and maintain and cause to be placed or maintained official traffic-control devices when and as required under this division to make effective the provisions of said division, and may place and maintain such additional traffic-control devices as he may deem necessary to regulate traffic under this division or under state law, or to guide or warn traffic.

B. Barriers may be erected by public utilities when and as authorized by the traffic authority. (Prior code § 11.04.090)