All private emergency vehicles shall be equipped with at least one lighted red light that flashes intermittently, visible under normal atmospheric conditions from a distance of five hundred feet to the front of the vehicle, and also equipped with a siren or whistle audible under normal traffic conditions for a distance of five hundred feet, and shall use both red light and siren or whistle when proceeding under an emergency situation. (Code 1962, § 37-34.07)