A peace officer, and, in the absence of a peace officer, any employee of the Fire Department when at the scene of a fire or incident, 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.
(Iowa Code §§ 102.4, 321.236(2)) (1999 Code, § 60.04)