Born before the car, the signal light was originally only for trains. At first, it was lit with gas. After 43 years they run on electricity but still need a maneuver until fully automatic in 1950. Initially the traffic signal did not have a yellow light and replaced it with a siren when needed.
The history of signal lights goes back to October 1868, when the lights were placed right next to the British parliament building in London. They are installed here to signal passing trains. On the elbow-shaped pillar are two lights: one red and the other blue for nighttime. A red light means stop and a green light means attention.
In August 1914, a traffic signal company was born in the United States and was responsible for installing lights at intersections in Ohio. The special thing was that at that time, the signal light did not have a yellow light, so when the police switched state, the police pressed the siren to alert the drivers.