(A)   It is the duty of the Police Department to enforce the street traffic regulations of the city and all of the state vehicle laws applicable to street traffic in the city, to make arrests for traffic violations, to investigate accidents and to cooperate with other officers of the city in the administration of the traffic laws and in developing ways and means to improve traffic conditions, and to carry out those duties specially imposed upon the Department by this chapter and any other traffic ordinances of the city.
   (B)   Officers of the Police Department or officers as are assigned by the Chief of Police are hereby authorized to direct all traffic by voice, hand or signal in conformance with traffic lays and ordinances.  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 and ordinances.
   (C)   Officers of the Fire Department, when at the scene of a fire or other emergency, may direct or assist the police in directing traffic thereat or in the immediate vicinity.
(`90 Code, § 20-2)