With the advent of the industrial age, especially the appearance of high-speed carriages and cars, it is no longer possible to ensure smooth traffic and protect pedestrians and vehicles only by conventional traffic habits. So in 1868, the first traffic light with the function of directing traffic appeared in Britain. It is said that the reason why it is forbidden to run red lights and allow green lights to pass is to refer to the dress style of ladies in Yorkshire, England at that time: wearing a red skirt means married, and wearing a green skirt means unmarried. Actually, it's not. At that time, people had studied spectral physics, and red had the strongest penetrating power, so as a sign of no walking, the opposite color was green, so it was chosen to represent traffic.
Interestingly, the first person who invented traffic lights was actually a textile worker. He came to London in 1859 with an oil lamp with a movable roof, but the invention was laughed at. It was not until a few years later that there were frequent accidents in high-speed cars on the streets of Britain that the government remembered this invention.
1868 65438+February 10, the first member of the signal lamp family was born in the Parliament Square in London. At that time, the lamp post designed and manufactured by Hart, a British railway signal engineer, was 7 meters high and hung with a red and green lantern-gas traffic signal lamp, which was the first signal lamp. At the foot of the lamp, a policeman with a long pole pulled the tape to change the color of the lantern. Unfortunately, 23 days after its appearance, the gas lamp suddenly exploded, resulting in the death of a policeman on duty. Since then, traffic lights in the city have been banned. It was not until 19 14 that traffic lights were restored for the first time in Cleveland, USA.
The appearance of yellow light is due to the increase of vehicle speed.
During World War I, traffic lights in the modern sense began to appear on the streets of the United States. Modern traffic lights first appeared in the United States because Europe was ravaged by war, and with the rise of the United States, the number of motor vehicles surged, and the streets where cars came and went became more and more dangerous, so electric traffic lights and linkage traffic lights came out one after another in the United States.
With the "silent command" of traffic lights in the United States, road traffic has become more orderly and safe, which has promoted the United States to become the first "country on wheels" in the world. Stimulated by the national patent application and economic development, dozens of technologies related to traffic light rules have been popularized, and flow control lights and computer-controlled traffic lights have appeared one after another, becoming the "originator" of modern traffic light rules.
The popularization of yellow light is a bit late. One of the main reasons for the appearance of yellow light is that the speed of vehicles is getting faster and faster. If a vehicle with a speed of 20 kilometers per hour can stop in time when the green light turns red, it will be more difficult for a vehicle with a speed of 40 kilometers per hour to stop in time: First, sudden braking may lead to rear-end collision and cause additional injuries; Second, according to the theory of physical inertia, it is difficult to stop suddenly.
Many China documents show that the inventor of the yellow signal lamp was Hu Ruding from China in 1927. Hu Ruding, who was studying in the United States at that time, thought it would be safer to add a yellow signal light between the red light and the green light. However, according to records, the world's first red, yellow, green, three-color and four-way traffic light was put into use in June of 1920 10. The signal lamp was invented by police officer William Potts and installed at the intersection of Woodward Street and Ford Street in Detroit. Yellow means "be careful". The railway system has been used for a long time. 1899, the railway systems in new york, New Haven and Hadford used tricolor lights, red means "stop", green means "clear all" and yellow means "be careful".