Are traffic lights in Washington state getting a fourth color?

For as long as I can remember, traffic lights have always had three colors. Red, amber and green. According to Wikipedia, the first traffic light showed up in the world in London in 1868. Instead of electric lights, it was the semaphore system, and it was used to replace a police officer.

In 1912, the first electric traffic light was developed by a policeman in Salt Lake City, Utah in 1920, the first three color traffic light was created by William Potts. In 1921, two stop lights were installed in Detroit, MI. loading...

In 1968 something called the Vienna Convention for Road signs and Signal lights Happened. They established standards that would be used, or mostly used around the world. Now for those of you who are confused about what the amber light means. If you live in America,