(A) It shall be the duty of the officers of the Police Department or such officers as are assigned by the Chief of Police to enforce all street traffic laws of this city and all state vehicle laws applicable to street traffic in this city.
(B) Officers of the Police Department, or officers assigned by the Chief of Police, are authorized to direct all traffic by voice, hand, or signal in conformance with traffic laws, provided that, in the event of a fire or other emergency, or to expedite traffic or to safeguard pedestrians, officers of the Police Department may direct traffic as conditions may require, notwithstanding the provisions of the traffic laws.
(C) Officers of the Fire Department, when at the scene of a fire, may direct or assist the police in directing traffic thereat or in the immediate vicinity.
('67 Code, § 70.11)