A.   Police Department: The police department shall have the power 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 the officers of the city in the administration of the traffic laws and in developing ways and means to improve traffic conditions.
   B.   Fire Department: Officers of the fire department, when at the scene of a fire or other emergency, may direct or assist the police in directing traffic there or in the immediate vicinity. (1983 Code § 15-117)