The Mayor, subject to any directions given by the City Council by motion or resolution, is authorized to place markers, buttons or signs within or adjacent to intersections indicating the course to be traveled by vehicles turning at such intersections. The course to be traveled, as so indicated, may conform to or be other than as prescribed by law and is hereby authorized to determine those street intersections at which drivers of vehicles shall not make right, left or other turns, and shall have proper signs placed at the intersections. The making of the turns may be prohibited between certain hours of any day and permitted at other hours. Where turns are restricted during certain hours pursuant to this Section, the same shall be plainly indicated on the signs, or they may be removed when turns are permitted. (1988 Code § 15-902)