Just last week, I took a friend of mine to the DMV so she could get a new license. While I waited 6 hours for her to finish up, I perused the official DMV literature to pass the time. As I was looking through the section on road signs, I asked myself, “What’s up with the different shapes?” A thought that has passed through everyone’s brains at one time or another. More specifically, I wondered, why do stop signs have 8 sides?

Photo Credit: Flickr, Paul Benson

It turns out there’s an actual reason, and it goes back almost 100 years, to the very invention of road signs. Early 20th century roads were a mess. It was pretty much every man and woman for themselves. There were no lanes and no signs at all. You didn’t even need a license to operate a car.

Photo Credit: Public Domain

The first stop sign debuted in Detroit in 1915 but looked nothing like the ones we are bombarded with on roads today. In 1923, folks who worked for Mississippi’s highway department suggested a new sign. One that would give drivers a heads-up that a potential hazard might be just up the road. The idea they came up with was that the more sides a sign had, the more dangerous was the road ahead.

Photo Credit: Library of Congress

A circle (considered to have infinite sides) denoted the riskiest stretches of road, such as railroad crossings. It was decided that the 8-sided octagon would represent a sign for intersections, the next level of potential danger. Diamond-shaped signs were next in line, followed by rectangles which are used only for information. In case you haven’t noticed, we still use all these sign shapes today.

Photo Credit: Public Domain

Next time you’re driving, think back to a time when the roads were essentially lawless, and thank those folks in Mississippi who had the foresight to try to keep us all safe.