When any motor truck having an unladen weight of four thousand pounds or more, any truck tractor irrespective of weight, or any trailer or semitrailer, is, at any time mentioned in 618 of the Vehicle Code, disabled upon the roadway, or within ten feet thereof, of any highway outside of any business or residence district, upon which highway there is insufficient street lighting to reveal a vehicle at a distance of two hundred feet, a warning signal of the character indicated in Section 590 of the Vehicle Code shall be immediately placed at a distance of approximately one hundred feet in advance of and one hundred feet to the rear of such disabled vehicle. The continuous flashing of at least four approved Class A-Type I turn signal lamps, at least two toward the front and at least two toward the rear of the vehicle shall be considered to meet the requirements of this section until the devices mentioned above and in said Section 590 of the Vehicle Code can be placed in the required locations. The warning signals herein mentioned should be displayed continuously during the times mentioned in said Section 618 while such vehicle remains disabled upon the roadway or within ten feet thereof. (Ord. 3658-NS § 1 (part), 1958)