The city manager, subject to any directions which the city council may give by motion or resolution, is hereby authorized:
A. To designate and maintain, by appropriate devices, marks or lines upon the surface of the roadway, crosswalks at intersections where in his opinion there is particular danger to pedestrians crossing the roadway, and at such other places as he may deem necessary.
B. To establish safety zones or islands of such kind and character and at such places as he may deem necessary for the protection of pedestrians. (1991 Code § 21-38)