Traffic lights are commonly known as traffic lights. In the early 19th century, in the central English city of york, the red and green dresses were different from women. Among them, women in red suits show that I am married and that the green women are unmarried. Later, London, United Kingdom, the house of parliament often attack the carriage rolled before the accident, so people are red green, December 10, 1868, the top of a light clan members of the parliament building in the square was born in London, by the then British mechanical ethics hart, planning, production of light 7 meters high, hanging on a light red, green lantern, traffic light gas, which is at the top of the city street light. At the foot of the lamp, a man with a long stick is doing whatever he wants to touch the color of the lantern. Later, the gas lampshade was installed in the center of the signal lamp, with two red and green glass in front of it. Unfortunately, the explosion of a gas lamp, which had only been available for 23 days, was extinguished, leaving a poor man on duty to die.

Since then, the city's traffic lights have been cancelled. It was not until 1914 that the city of Cleveland, in the United States, was the first to recover. Later, in cities such as New York and Chicago, road traffic lights were presented from scratch.

Following the development of various means of transportation and the demand of traffic conductors, the top of the list (red, yellow, green, three signs) was born in 1918. It was a three-colour circular projector, installed on a tower on 5th street in New York City, because of its birth, which greatly improved urban traffic.