Whenever authorized signs are erected indicating that no right or left or U-turn is permitted no driver of a vehicle shall disobey the directions of the sign. When authorized marks, buttons, or other indications are placed within an intersection indicating the course to be travelled by vehicles, no driver of a vehicle shall disobey the directions of the indications. The intersections at which certain turns are prohibited, and the prohibited turning movements are described in Chapter 77, Schedule I.
('64 Code, § 21-39)