All official traffic signals, signs, and other control devices within the city used in regulating and directing traffic must be obeyed, unless otherwise directed by a police officer; and on public highways where authorized signs are erected, indicating that no left, right, or “U” turn is permitted, no person or persons operating a bicycle in the city shall disobey the regulation contained therein, except that when such person dismounts from the bicycle to make any such turn, he shall obey all the traffic ordinance provisions applicable to pedestrians.
('71 Code, § 5-3) Penalty, see § 70.99