How Did The Stop Sign Get Its Shape?

On Monday I wrote about how I am not good at noticing things. One thing I do always notice is a stop sign. It could be my attention to detail 15 years ago in my drivers ed class, but more realistically it probably has to do with the shape.

The shape just stands out. Unless you are a big fan of UFC, the octagon is probably not a shape you see very often. Outside of a stop sign, that is.

That got me wondering…Why did they pick the octagon as the shape of the stop sign? And who decided it would be red? Let’s find out…

How Did The Stop Sign Get Its Shape?

In the early years of the automobile, the streets were a chaotic place. There were horses, bicycles and cars, but very few rules. There were no drivers licenses, speed limits or Uber.

In a 1900 article titled “Reforming Our Street Traffic Urgently Needed,” for Rider and Driver magazine, William Phelps Eno proposed to clean up this mess by placing stop signs at intersections. However, it wasn’t until 1915 that Detroit installed the first official stop sign, a 2-by-2-feet sheet of metal with black lettering on a white background.

In 1923, the Mississippi Valley Association of State Highway Department developed the street-sign shapes, many of which we still follow today. Among other reasons, they picked the unique eight-sided shape because it would allow drivers facing the back of the sign to identify that oncoming drivers have a stop sign and prevent confusion with other traffic signs. Since original signs were not reflective, it was also chosen so that it could be identified easily at night.

So the shape was determined in 1923 but it was not until 1935 that the color of the sign was decided. Traffic engineers created the first uniform standards for the nation’s road signage, known as the Manual on Uniform Traffic Control Devices. Originally, the Manual recommend a yellow stop sign with black letters. in 1954, a revision was made for the sign to be red with white letters, which followed the color-coding system developed for the railroad and traffic signals.

Here are some fun images of stop signs:


1915 Detroit Stop Sign



Old American Stop Sign



Ethiopian Stop Sign (looks like it says, Stop and High Five)




Stop Hammer Time



Source: New York Times & Wikipedia

Cover photo credit: Flickr