(A) Every person riding a bicycle shall obey the instructions of official traffic-control signals, signs and other control devices applicable to vehicles, unless otherwise directed by a police officer.
(B) Whenever authorized signs are erected indicating that no right, left or U turn is permitted, no person operating a bicycle shall disobey the direction of any such sign; except, that when such person dismounts from the bicycle to make such turn, he shall then obey the regulations applicable to pedestrians.
(`90 Code, § 6-2) Penalty, see § 73.99