It's difficult to find a modern person who has never seen a traffic light. The device, which alternately illuminates red, yellow, or green lights at regular intervals, regulates the movement of vehicles and pedestrians.

    Everyone knows the meaning of these signals from childhood, but not everyone is aware of why these specific colors were chosen for the light signals.

    In 1868, the world's first traffic light appeared on a street near the London Parliament. The device was designed to slightly ease traffic congestion on Bridge Street, which was very crowded. The idea for such a device came from engineer John Peake Knight. However, objectively speaking, he simply adapted this device from a railway semaphore.

   Before the eyes of the cabin and diligence drivers, a portable axle pole with a height of 6.7 meters appeared. They leaned in opposite directions (the "Stop" sign) or down to 45 degrees (the "Attention" signal is used for authorization). In the evening, a gas lamp with red and green lenses was used. For the system to function, the police were on unstable duty at the traffic light 24 hours a day.

   Thus, the red and green colors used in the railway semaphore were borrowed for the current traffic light. Interestingly, initially, the "attention" sign is represented by green, and after the white signal, movement is permitted. However, such a procedure proved to be unsuccessful. Engineers sometimes took large stars in the sky as a semaphore sign, and this led to many disasters. 

   Only ten years later was it possible to explain why red, green, and yellow lights were established as standard colors for physicists. Among the colors in the rainbow, these colors have the longest wavelengths in the spectrum. Therefore, these signals are visible from the maximum distance.

Collector: Mamura Turaeva