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0 Comments | May 11, 2018

Why Do Stop Signs Have Eight Sides?

Red and white MUTCD stop sign

Considering many drivers can’t recall traffic sign designs, it’s only right that we discuss the most important sign on the road: the Stop Sign. At the turn of the 20th century, before speed limits, lanes, and driver licenses existed, American roads were chaotic. Out of that chaos, traffic signs were born.

Stop Signs Make an Appearance

The first stop signs were posted in Detroit in 1915, but they didn’t resemble the red octagonal signs most of us know today. Originally, they were 24 by 24 inch squares that had black text on a white background. Since there weren’t many cars on the road, they were probably adequate enough in most situations. However by the 1920s, the number of cars on the road skyrocketed and the U.S. standardized all stop signs to be octagonal.

Stop Signs Become Eight Sided

“Why do stop signs have eight sides?” you may ask. The Mississippi Association of State Highway Departments wanted to keep things fairly simple: the more sides a sign has, the more dangerous the road is ahead. For example, round signs, such as railroad crossings, are the most dangerous because they were considered to have infinite sides. Octagonal signs, such as stop signs, denote the second most dangerous stretch of road. Diamond shaped signs were for warnings. The rectangle and square shapes, meanwhile, were chosen as informational/regulatory signs. The concept behind the shapes worked so well that they continue to exist today.

Stop Signs Turn Red

Even after the shape was selected, the stop sign didn’t see a color change until 1935. You probably wouldn’t recognize it today though, because the nation’s first uniform standards on road signage, the Manual on Uniform Traffic Control Devices, recommended a yellow stop sign with black letters. It wasn’t until a 1954 revision that the stop sign became red with white letters. The colors were arbitrary though, it followed the color-coding system developed for railroads and traffic signals.

Now that you know why stop signs have eight sides, perhaps you’ll have an easier time recalling its design.