Red Green

why are traffic lights green,yellow and red and not any other colour?

why cant it be pink purple and blue.why only red green and yellow.

In 1920 Police Officer William Potts addressed the chaotic traffic of Detroit, Michigan, by co-opting the red, amber, and green automatic traffic light system used on railroads. Around the same time, the prolific African American inventor Garrett Morgan devised and patented the precursor to the automatic traffic lights we use today.

Apparently the colors of red and green were standard in the electrical industry at the time. The makers of railroad signals and traffic lights simply adopted the familiar color scheme.

Red-Green Bike