Red, Yellow, Green _____ Rest, Set, Go vroom vroom

Why are the traffic lights worldwide of red, yellow, green color only? There is a history behind it.

Why only Red, Yellow and Green?

You see traffic lights in these colors almost every day, but have you ever given a thought that why only these colors? And why not others? It would be interesting to know that traffic lights or signals originated even before the time, cars came on roads. In earlier days, they were used to signal trains.

History of Red, Yellow and Green?

But in case of trains, the red light was used to stop, and white to go, but green light was used as a signal of carefulness, like of yellow in road signs. But that white light used to create hindrances for train drivers. Even, once train driver started the train to see a blinking star as an indicator of white light. After such incidences, white light was changed to green. And instead of green, yellow light was introduced, which was quite an effective move. And it lowered the number of incidents to a considerable number.

RED, A Warning

As far as red color is concerned, it is a sign of alarm or danger in many cultures, and this thought is even before car invention. The reason for choosing it is that it is of maximum wavelength and the driver can view it from the largest possible distance. Yellow light’s wavelength is just little shorter than red light and so, it is a message for diver to be careful.

But you may also not know that yellow light had been used in past in the 1900s, as a stop sign. It was done especially in low light regions where it was hard to see the red color. But with time, such materials are used which can reflect the light to its maximum extent, and so stop, ready and go indications are spotted as red, yellow and green light.

via Dawn