History of traffic lights
At the beginning of the 19th century, in York City in central England, red and green clothes represented different identities of women. Among them, a woman in red dress said that I was married, while a woman in green dress was unmarried. Later, in the front of the London Parliament Building, there was a frequent accident of the carriage rolling, so people were inspired by the red and green. On December 10, 1868, the first member of the signal light family was born in the square of the London Parliament Building. The British mechanic De Hart designed and manufactured the lamppost 7 meters high, with a red and green lantern on the body - the gas traffic signal, which is the first signal light on the city street. At the foot of the lamp, a policeman with a long pole can pull the belt to change the color of the lantern as he pleases. Later, a gas lampshade was installed in the center of the signal light, and two red and green glass were alternately blocked in front of it. Unfortunately, only 23 days of gas lamps suddenly exploded, causing a police officer on duty to ruin his life.
Since then, the city's traffic lights have been banned. It was not until 1914 that Cleveland in the United States took the lead in recovering traffic lights, but it was already an "electrical signal light." Later in the cities of New York and Chicago, traffic lights reappeared.
The emergence of red, yellow and green traffic lights
With the development of various modes of transportation and the need of traffic command, the first three-color lamp (red, yellow, and green) was born in 1918. It is a three-color circular four-sided projector that was installed on a high tower on Fifth Street in New York City. Due to its birth, the city's traffic was greatly improved.
The inventor of the yellow signal light is Hu Yuding of China. He went to the United States with the ambition of "scientific saving the country" and worked as a staff member at the General Electric Company of the great inventor Edison. One day, he stood at the bustling crossroads waiting for the green light signal. When he saw the red light and was about to pass, a turning car slammed through the ground and scared him into a cold sweat. Back in the dormitory, he repeatedly pondered, finally thought of adding a yellow signal light in the middle of the red and green lights to remind people to pay attention to danger. His suggestion was immediately confirmed by the relevant parties. Therefore, the red, yellow and green signal lights are a complete family of command signals, covering the land, sea and air transportation fields all over the world.
China's first street lamp
The earliest road traffic lights in China appeared in the British Concession in Shanghai in 1928.
Traffic lights and vehicles
From the earliest hand straps to the electrical control of the 1950s, from computer control to modern electronic timing monitoring, traffic lights are constantly updated, developed and improved in science and automation.
The traffic light was invented by the African American Garrett Morgan in 1923. Previously, rail traffic had been using auto-converted lighting signals for some time. However, since the train is operated in a single train according to a fixed schedule, and the train is not very easy to stop, the signal used on the railway has only one command: pass. The traffic lights of road traffic are different. Its duty is to tell the car driver to stop the car.
People who drive do not want to see the parking signal. James, a psychologist at the University of Hawaii, points out that people have a tendency to connect brakes and throttle with self-esteem. He said: When the driver saw the yellow light, his heart was secretly prepared for acceleration. If the red light is on at this time, there will be a feeling of disappointment. He called the intersection "the psychological power zone." If his theory is true, this area should belong to the category of supere go rather than instinct (id) in Freudian psychology theory.
New traffic lights can take pictures of people with red lights. The driver who committed the crime will soon receive a fine. Some traffic lights also have the ability to monitor the speed of the vehicle.
The earliest traffic lights appeared in London, England in 1868. At that time, the traffic lights were only red and green. After the improvement, a yellow light was added. The red light indicates stop, the yellow light indicates preparation, and the green light indicates traffic.
The effect of traffic light color on vision
In fact, using these three colors to communicate the communication number is related to the visual function structure and psychological reaction of the person.
Our retina contains rods and three cone-shaped photoreceptors. Rod cells are particularly sensitive to yellow light, and the three cones are most sensitive to red, green and blue light, respectively. Due to this visual structure, it is most easy for people to distinguish between red and green. Although yellow and blue are also easy to distinguish, but because of the eyeball, there are fewer photoreceptors that are sensitive to blue light, so it is better to distinguish between colors and red and green. Therefore, what color is used for traffic lights is also asked by the university!
Color also has the meaning of activity. To express heat or violent, the strongest is red, followed by yellow. Green has a colder and calmer meaning. Therefore, people often represent danger in red, yellow as alert, and green as safety.
Moreover, since the red light has the strongest penetrating power, the light of other colors is easily scattered, and it is not easy to see in the fog, and the red light is the least likely to be scattered. Even if the visibility of the air is low, it is easy to be seen. No accidents will occur. So we use red to prohibit.
Relevant laws and regulations
Implementation Regulations of the People's Republic of China Road Traffic Safety Law
Article 38: Motor vehicle signal lights and non-motor vehicle signal lights indicate:
(1) When the green light is on, the vehicle is allowed to pass, but the turning vehicle shall not obstruct the passing of the straight-through vehicles and pedestrians;
(2) When the yellow light is on, the vehicle that has crossed the stop line can continue to pass;
(3) When the red light is on, vehicles are prohibited from passing.
In the case where no non-motor vehicle signal lights and pedestrian crossing signal lights are provided, non-motor vehicles and pedestrians shall follow the indications of the motor vehicle signal lights.
When the red light is on, the right-turning vehicle can pass without obstructing the passing vehicles and pedestrians.
Article 39: Crosswalk signal lights indicate:
(1) When the green light is on, pedestrians are allowed to pass the crosswalk;
(2) When the red light is on, pedestrians are prohibited from entering the crosswalk, but if they have entered the crosswalk, they can continue to pass or wait at the centerline of the road.
The fortieth lane signal light indicates:
(1) When the green arrow light is on, the vehicle in the lane is permitted to pass in the direction indicated;
(2) When the red fork light or the arrow light is on, the traffic of the lane is prohibited.
The direction of the arrow of the direction indication signal light to the left, up, and right respectively indicates left turn, straight turn, and right turn.
Article 42 The flashing warning signal light is a yellow light that continues to flash, indicating that the vehicle and pedestrians should pay attention to the passage when passing, confirm the safety and pass.
Article 43 When there are two red lights alternately flashing or a red light is on at the intersection of road and railway plane, it means that vehicles and pedestrians are prohibited from passing; when the red light is off, it means that vehicles and pedestrians are allowed to pass.
Feyvan electronics offers a wide variety of cable assemblies including Servo Motor, Sensor, Automotive, Medical and other custom wire harness to help you prepare for installation. Whether you need cables, connectors, electrical components, tapes or heat shrink tubes, we have the products for you.
Our cable parts and accessories offer safe and efficient ways to get the job well done, all of which are RoHS, UL and CSA compliant. More than 10 years experiences of professional engineers ensure that your custom cables, assemblies, connectors and harnesses are perfectly suited to meet your exact requirements.
Wire Harness
Wire Harness,Cable Assembly,Cable Harness,Wire Assembly
Feyvan Electronics Technology Co., Ltd. , http://www.fv-cable-assembly.com