Traffic Light Color

  •  Traffic light colors are based on universal standard. According to the International Commission on Illumination (CIE), colors that can be used for traffic lights are “red, yellow, green, blue, purple and white,” but we use only “red, yellow and blue-green” in most cases. Although a green light might look completely green, the actual color is usually blue-green. Since our eyes are sensitive to green, we view the blue-green light to be green light.


     Also, Japanese people refer to a green light as “青信号 (blue light),” though, we look it’s green. It is said that the reason is that we represented all colors from green to blue using only the word “blue,” or we thought the contrast of red is blue.

    Original sentence