A peace officer, any officer of the Fire Department when at the scene of a fire, or a person directed to do so by a peace officer or otherwise authorized by the City is authorized to direct all traffic by voice, hand, or signal in conformance with traffic laws. In the event of an emergency, traffic may be directed as conditions require, notwithstanding the provisions of the traffic laws.
(Code of Iowa, Sec. 102.4 & 321.236[2])