Explained: this is why traffic lights are green, red and yellow

Have you ever asked yourself why traffic lights are colored the way they are? One day someone needed to choose colors for traffic lights and they opted for green, yellow, and red. Why is that? Maybe you’ve never actually stopped and thought about it. Or maybe you’ve been thinking about it for a very long time now. Either way, you’re going to have an answer to that question today. You can learn more below.

Origin

To know why they picked these colors, it’s useful to learn a little about the history of traffic lights (and their colors). The first traffic light was placed in the nation in 1910. Whistles and lights were used by policemen to inform drivers when to stop and when to proceed, to maintain the movement of autos. In 1920, the first traffic light was invented by William Potts. Then, there was no law regarding what colors or patterns must be employed. So, these lights all appeared differently wherever you were. In 1935, the Federal Highway Administration published the “Manual on Uniform Traffic Control Devices,” in which it established standards for all signs and signals. In this manual, it also made traffic lights throughout everywhere red, yellow, and green.

How then did these particular colors arise? Prior to traffic lights, trains had already been employing light signals to assist in the flow of train traffic. In these traffic signal lights, red indicated halt, white indicated proceed, and green indicated “caution proceed.” When white proved to be a problem (it could be confused with causing something else by train drivers and resulting in accidents), they switched the ‘proceed’ signal from white to green. Yellow was the color designated for “proceed with caution” because it was easier to see.

Red

But why red? Red is the longest wavelength of color. That means you can view it from afar. This is very useful when it comes to warning signs and traffic lights that need you to stop for safety purposes. Now you know why the colors of traffic lights have a history spanning more than a century. This is certainly an interesting fact to pass around at a party!