The history of signal light development
Release time：
2023-03-02 14:22
Source：
In 1858, a mechanical wrench type signal in red and blue with coal-fired gas as the light source was installed in the main street of London, England to direct carriages to pass. In 1868, British mechanical engineer Naite installed the world's earliest gas traffic light in the square in front of the Palace of Westminster in London. It consisted of red and green rotating square glass lights, red for "stop" and green for "attention". On the 23rd day of its operation, the gas light suddenly exploded, killing a policeman on duty, and was cancelled.
In 1914, the electrically activated traffic light appeared in the United States. The light consisted of a red, green and yellow circular light projector, and was installed on a tower on 5th Street in New York City. The red light means "stop" and the green light means "pass".
In 1918, there were controlled traffic lights and infrared traffic lights. With the control of the traffic lights, one is the pressure detector placed in the ground, the vehicle will turn green when approaching the red light; another is to use the loudspeaker to start the traffic lights, the driver opportunity to press the loudspeaker when the red light, so that the red light to green light. Infrared traffic lights when pedestrians step on the pressure-sensitive road, it can detect that someone is going to cross the road, infrared beam can extend the red light of the signal for a period of time, delaying the release of cars to avoid traffic accidents.
The emergence of signal lights, so that traffic can be effectively controlled, for the diversion of traffic flow, improve road capacity, reduce traffic accidents have obvious effects. 1968, the United Nations "road traffic and road signs and signals agreement" on the meaning of a variety of signals made. The green light is a signal for passage, and vehicles facing the green light can go straight, turn left and turn right, unless another sign prohibits a particular turn. Left and right turning vehicles must give priority to vehicles that are legally moving through the intersection and pedestrians crossing the crosswalk. A red light is a no-traffic signal, and vehicles facing a red light must stop behind the stop line at the intersection. The yellow light is a warning signal; vehicles facing the yellow light cannot cross the stop line, but may enter the intersection if they are too close to the stop line to stop safely. Since then, this rule has become common throughout the world.
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The scientific basis of the light color of the traffic signal
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In the intersection, four sides are hanging red, yellow, green, three color traffic signal, it is silent "traffic police". Red and green lights are the international unified traffic signals. Red light is the stop signal, green light is the signal to pass. Intersection, several directions to the car are gathered here, some want to go straight, some want to turn,
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