All officers of the Police Department, or such other persons as may be so assigned by the Chief of Police, are hereby authorized to direct and control all traffic by voice, hand, sign or signals in conformance with law. However, during a fire or any other emergency, or because of the street condition or in order to expedite traffic or safeguard persons or property, any police officer shall have the power to direct, control, divert or exclude traffic, as conditions may then and there require, notwithstanding any other provisions of law.
('77 Code, § 10-3)