The director of public works may make regulations necessary to make effective the provisions of this title and to make and enforce temporary regulations to cover emergencies and special conditions, and also to determine and designate the character of all traffic signs and signals required by this title. The director may also erect and maintain, at dangerous intersections and other hazardous locations, slow, danger or warning signs or signals, with a speed limitation not inconsistent with 625 Illinois Compiled Statutes 5/11-601. (1976 Code § 41.04)