Every vehicle already stationary when the fire alarm shall have been sounded must remain so for a period of five (5) minutes after the sounding of the fire alarm. No vehicle, except by the specific direction of the Fire Chief or Assistant Fire Chief, shall follow, approach or park closer than five hundred (500') feet to any fire vehicle, or to any fire hydrant to which a hose is connected. Nothing herein shall be construed to apply to vehicles carrying doctors, members of the Fire Department, or emergency vehicles. (Ref. 60-6,183 RS Neb.)