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Where are the traffic lights?
- Oct 02, 2018 -

"Stop at the red light, go at the green light", we are used to it. But when did the traffic lights come into use, which country and which city they were first used in, who invented them, and when did they start to be used internationally? Looking forward to your reply

On December 10, 1868, the first member of the signal lights family was born in the square of the houses of parliament in London. The lamppost designed and manufactured by the British mechanic DE hart was 7 meters high, and he was wearing a red and green lantern, the gas traffic light, which was the first light on the city street. At the foot of the lamp, a police officer with a long pole changes the color of the lantern by shifting the belt at will. Later, a gas chimney was installed in the center of the signal light, with two pieces of red and green glass alternating in front. Unfortunately, a gas lamp that had been on the scene for only 23 days suddenly exploded, killing a policeman on duty.
Since then, city traffic lights have been banned. It wasn't until 1914 that traffic lights were restored in Cleveland, but this was the "electric light." Traffic lights later reappeared in cities like New York and Chicago.
With the development of various means of transportation and the demand of traffic command, the first true tri-color lamp (red, yellow and green signs) was born in 1918. It is a three-color, circular, four-sided projector that was installed on a tower on fifth street in New York City.
The inventor of the yellow light is hu ruding of our country. He went to the United States with the ambition of "saving the country through science" and worked as a clerk in the American general electric company where the great inventor Thomas Edison was the chairman. One day, he stood at a busy intersection waiting for the green light signal. When he saw the red light and was about to pass, a turning car passed by with a loud exclamation, which scared him into a cold sweat. Back in the dorm, he thought about it and finally thought of adding a yellow light to the red and green lights to alert people to the danger. His suggestion was immediately recognized by the concerned parties. So the red, yellow and green signal light is a complete command signal family, all over the world land, sea, air traffic field.
The earliest road traffic light in China appeared in the British concession in Shanghai in 1928.
From the earliest hand leash to the electrical control in 1950s, from the use of computer control to the modern electronic timing monitoring, traffic lights are constantly updated, developed and perfected in the scientific and automatic way.
The traffic lights are African American Garrett. Morgan invented it in 1923. Rail traffic has been using auto-switching light signals for some time. But because the train is run in a single line according to a fixed timetable, and it is not easy to stop the train, there is only one order for the signal to be used on the railway: to pass. Traffic lights on roads are different, and their job is largely to tell motorists to stop.
Nobody in the car wants to see a stop sign. James, a psychologist at the university of Hawaii in the United States, pointed out that people have a tendency to associate the brake and accelerator with self-esteem. When motorists see the yellow light on, they are secretly ready to speed up, he said. If the red light turns on, a sense of disappointment immediately follows. He calls intersections "psychodynamic zones." If his theory holds up, the field in freudian psychology should belong to the category of superego (supere go) rather than instinct (id).
New traffic lights can take pictures of people running red lights. The offending driver will soon receive a ticket. Some traffic lights also monitor the speed of vehicles.
The earliest traffic lights appeared in London, England in 1868. At that time, the traffic lights were only red and green. After being improved, another yellow light was added. The red light means stop, the yellow light means prepare, and the green light means pass.
In fact, the use of these three colors as traffic signals is related to the visual structure and psychological reactions of people.
Our retina contains rods and three cones. The rods were particularly sensitive to yellow light, while the three cone cells were most sensitive to red, green and blue light, respectively. Because of this visual structure, people can distinguish red from green. Although yellow and blue are also easy to distinguish, due to the lack of photoreceptors sensitive to blue light in the eye, red and green are preferred. Therefore, traffic lights with what color is also asked by the university ah!
Color also has the meaning of activity. To express heat or intensity, the strongest color is red, followed by yellow. Green has a cold and calm meaning. Therefore, people often represent danger in red, alert in yellow and safety in green.
Moreover, because red light is the most penetrating light, other colors of light are easily scattered. It is not easy to see in foggy days, while red light is the least easy to be scattered. Even if the air visibility is relatively low, it is easy to be seen and accidents will not happen. So we'll do it in red.

Author:Bunny Sun