The Chief of Police is hereby authorized:
(a) To designate and maintain, by appropriate devices, including 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 of such kind and character and at such places as he may deem necessary for the protection of pedestrians.