The Chief of Police is hereby authorized:
1. To designate and maintain by appropriate devices, marks or lines upon the surface of the roadway, crosswalks at intersections where, due to traffic conditions, there is particular danger to pedestrians crossing the street or roadway, and at such other places as traffic conditions require.
2. To mark lanes for traffic on street pavements at such places as traffic conditions require, consistent with the traffic Code of this City. Where traffic lanes have been marked, it shall be unlawful for the operator of any vehicle to fail or refuse to keep such vehicle within the boundaries of a lane except when lawfully passing another vehicle or preparatory to making a lawful turning movement.