The City Council shall determine those intersections at which drivers of vehicles shall not make a right, left, or U-turn and shall place proper signs at the intersections. The making of the turns may be prohibited between certain hours of any day and permitted at other hours, in which event it shall be plainly indicated on the signs or they may be removed when the turns are permitted. When signs are so placed, it shall be unlawful to make a turning movement in violation thereof at the intersections described in Traffic Schedules XV, XVI, XVII, and XVIII, hereby incorporated herein.
('58 Code, §§ 16-30 and 16-31)