The Chief of Police 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 believes necessary;
(b) To establish safety zones of such kind and character and at such places as he believes necessary for the protection of pedestrians;
(c) To mark lanes for traffic on street pavements at such places as he believes advisable, consistent with the Traffic Code. (1947 Code §19.29)