Whenever authorized signs are placed which indicate that no "right", "left", or "U" turn is permitted, the driver of a vehicle shall obey the directions of that sign. When authorized markers, buttons, or other indications are placed within an intersection which indicate the course to be traveled by vehicles traversing or turning, the driver of a vehicle shall obey the direction of such indications.
('70 Code, Ch. E, Art. IV § 2) Penalty, see § 70.99