(a) Officers of the Police Department or such other personnel as are assigned by the Chief of Police shall enforce all traffic laws of the City and all State vehicle laws.
(b) Such officers are hereby authorized to direct all traffic by voice, hand or signal in conformity with traffic laws, provided that in the event of a fire or other emergency or to expedite traffic or safeguard pedestrians, officers of the Police Department may direct traffic as conditions may require, notwithstanding the provisions of the traffic laws.