Every motor truck having an unladen weight of four thousand (4,000) pounds or more, and every truck or tractor, irrespective of weight when operated upon any street or highway during darkness, shall be equipped with and carrying at least two (2) flares or two (2) warning lights or reflectors, which reflectors shall be of a type approved by the department of California highway patrol. When any vehicle above mentioned is disabled upon streets or highways within this city where there is insufficient street lighting to reveal the vehicle at a distance of two hundred feet (200') during darkness, a warning signal of the character indicated above shall be immediately placed at a distance of approximately one hundred feet (100') in advance of and one hundred feet (100') to the rear of such disabled vehicle by the driver thereof. The warning signal herein mentioned shall be displayed continuously during darkness while such vehicle remains disabled upon such street or highway. (1975 Code §9-10.12)