Why do traffic lights use red, yellow and green? What is the origin?

/kloc-At the beginning of the 9th century, in Yorktown, central England, red and green clothes represented different identities of women. Among them, the woman in red said that she was married and the woman in green was unmarried. Later, the carriage ran over people in front of the Parliament Building in London, England, and people were inspired by red and green clothes. 186865438+February 10, the first member of the signal lamp family was born in the Parliament Building Square in London. At that time, Hart, a British mechanical teacher, designed and manufactured a lamp post 7 meters high with a red and green lantern hanging. At the foot of the lamp, a policeman with a long pole pulled the belt to change the color of the lantern at will. Later, a gas lampshade was installed in the center of the signal lamp.

There are two red and green glasses in front of it. Unfortunately, the gas lamp that had been on for only 23 days suddenly exploded, killing 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. However, it is already an "electronic signal lamp". Later, traffic lights reappeared in new york, Chicago and other cities.

With the development of various means of transportation and the need of traffic command, 19 18 gave birth to the first true tricolor lamp (red, yellow, green). It is a three-color circular four-sided projector, which is installed on a tower on Fifth Street in new york. Because of its birth, urban traffic has been greatly improved.

The inventor of the yellow signal lamp is Hu Ruding in China. With the ambition of "saving the country through science", he went to the United States for further study and worked as a clerk in the American General Electric Company with Edison as its chairman. One day, he stood at a busy intersection waiting for the green light signal. When he saw that the red light was about to pass, a turning car roared past, which scared him into a cold sweat. Back in the dormitory, he pondered it over and over again, and finally thought of adding a yellow signal light between the traffic lights to remind people of the danger. His suggestion was immediately affirmed by relevant parties. Therefore, in the field of land, sea and air transportation, red, yellow and green signal lights have spread all over the world as a complete command signal family.

The earliest traffic lights in China appeared in the British Concession in 1928.

From the earliest handheld to the electrical control in 1950s, from computer control to modern electronic timing monitoring, traffic lights are constantly updated, developed and improved in science and automation.

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Is the traffic light African-American Gallette? Morgan invented it on 1923. Previously, railway traffic has been using automatic transfer light signals for some time. However, because the trains run in a single row according to a fixed timetable, and it is not easy for the trains to stop, there is only one command used on the railway: pass. Road traffic lights, on the other hand, are responsible for telling car drivers to stop to a great extent.

Drivers don't want to see the stop signal. James, a psychologist at the University of Hawaii in the United States, pointed out that people have a tendency to associate brakes and accelerator with self-esteem. He said: When the driver saw the yellow light, he secretly prepared to speed up. If the red light is on at this time, there will be a feeling of disappointment immediately. He called this intersection "psychological dynamic zone". If his theory holds, this region should belong to the superego rather than the instinct (id) in Freud's psychological theory.

The new traffic lights can take pictures of people who run red lights. The guilty driver will receive a ticket soon. Some traffic lights also have the function of monitoring the speed.

The earliest traffic lights appeared in 1868 in London, England. The traffic lights at that time were only red and green. After the improvement, a yellow light is added, red light means stop, yellow light means preparation, and green light means passage.

In fact, using these three colors as traffic signals is related to people's visual function structure and psychological reaction.

Our retina contains rod-shaped and cone-shaped photoreceptor cells. Rod cells are particularly sensitive to yellow light, while three cone cells are most sensitive to red light, green light and blue light, respectively. Because of this visual structure, people can easily distinguish between red and green. Although yellow and blue are easy to distinguish, red and green can distinguish colors better because there are fewer photosensitive cells in the eyeball that are sensitive to blue light. So what color is used for traffic lights is also asked by the university!

Colors also have active meanings. Indicates heat or intensity, the strongest is red, followed by yellow. Green has a colder and calmer meaning. So people often use red for danger, yellow for vigilance and green for safety.

Moreover, because red light has the strongest penetrating power, other colors of light are easy to be scattered, and it is not easy to see in foggy days, while red light is the least easy to be scattered, and it is easy to see even if the air visibility is low, and no accidents will occur. So we use red to indicate prohibition.

Traffic signals have a history of 100 years. It has gone through the control process from manual to automatic, from point to line and from line to surface. The first traffic light in the world was 1868 in Westminster, London, England. The traffic lights at that time were lit with gas. Because of the explosion caused by the use of gas, the police were injured, which also diluted the interest in studying traffic signals. It was not until 19 14 that the traffic lights of electric switches were used in Cleveland, Ohio, USA. This device laid the foundation of modern traffic command signals. The first traffic light in China appeared in 1929. According to records, the traffic lights in Beijing first appeared in Xijiaomin Lane at 1932. The earliest traffic light is a veritable traffic light, because it has only two signals: red light and green light. 19 18 manual three-color traffic lights were born in new york, USA. At that time, the yellow light signal was set for vehicles changing lanes left and right. Until the late 1970s and early 1980s, China still used green and yellow lights to turn left. With the appearance and development of automobiles, people realize that automobiles are a high-speed means of transportation. If the vehicle turns red when it meets the green light, it is easy to hurt passengers because of sudden braking. Around 1925, the manual three-color traffic lights used in Piccadilly Street in London, England, put the yellow light in front of the red light as a preparatory signal for the driver to stop. Now our common green light flashes first, then turns yellow, and then turns red, which is how it develops. 1926, the British used the world's first automatic traffic light, which is a mechanical one-off periodic traffic light, that is, the time of green light and red light is single and constant. However, people gradually found that the change of single-cycle red light and green light could not meet the needs of traffic flow change, so traffic lights controlled by multi-cycle signal machines were developed. With the development of electronics and other technologies, automatic traffic lights have also appeared. Its birth laid the foundation for computer-controlled traffic lights. The traffic lights with single point and fixed period only solve the traffic command problem at one intersection. But people always want the green light all the way to the finish line, so in the 1930s, people began to study a kind of green light line to control traffic lights. 1954 the former federal Republic of Germany adopted the line control mode of pre-signal and speed indication for the first time. It is on a main road, besides setting traffic lights at intersections, it also sets pre-signals and high-speed signals at a certain distance, that is, installing traffic lights on road sections to make vehicles power at a certain speed and ensure smooth intersections. Beijing used a similar line to control traffic lights in February 1985. However, by-wire control can only solve one line, but it can't solve the problem of one region and one city. People began to study the traffic lights of regional control. The appearance of computers opened the door to the field of traffic lights. The traffic lights controlled by computer area are produced by 1959. It has been widely used in developed countries. It was in June1987165438+10 that Beijing first used traffic lights at 39 intersections in the eastern district. Then the central, western and northwest regions were established and used one after another. So far, Beijing has realized network management. You may not be familiar with the red and blue lights that have been used for a long time. In view of the fact that drivers can't distinguish between green light and red light under certain circumstances, traffic accidents are prone to occur, which affects the smooth flow of roads. So I tried red and blue lights in Beijing. This red and blue light is not only easy to identify, but also needs almost no maintenance for life, and the power consumption is only one-fifth of that of the red light. In the future, with the continuous changes and development of people's production and life, there may be "traffic lights" of other colors, but the ultimate goal is traffic and safety.