Road signs appear in a wide variety of different colors and shapes, from yellow triangles to orange diamonds, and, of course, the iconic red stop sign octagon. The reasons why traffic signs appear in these specific shapes is by no means an accident or a mystery. In fact, there is some clever psychology behind the selection of traffic sign shapes, which we lay out in this article.
It all began in 1923 in the state of Mississippi. You see, at that time, stops signs were white and square across the country, but the state’s highway department believed that the white and square sign didn’t attract enough attention and drivers would be more prone to miss it.
As an improvement to the then-current system, they suggested that the shape of each sign ought to reflect the level of danger. While a simple square sign would be informative, a stop sign should be octagonal because its message is more urgent.
Although many of us haven’t been taught about this pattern, drivers still follow and understand it intuitively, and at times, subconsciously. This is because our brains naturally recognize shapes that are more complex as more noteworthy, and so a simple triangle, circle, or square would not be as catchy as, let’s say an octagon.
Needless to say, this system worked, and today, the US Department of Transportation denotes a specific shape and color to each road sign. Each shape carries a specific message. For example, the octagon is a complex shape, a mix of a square and circle, and so it suggests power and importance. Since the stop sign is considered to be the most important traffic sign, it is also bright red in color, which our brains are wired to notice immediately.
On the opposite side of the spectrum, an oval shape has no angles and is more natural and soft, so oval signs of different neutral colors like green or yellow are generally used for friendly, polite notices. Neutral, yet still formal instructions are usually shown on square or rectangular signs, which are also the two most common traffic sign shapes.
More urgent messages, like ‘road work ahead’, in turn, must be shown in bright colors like yellow, orange, and red, pictured on triangular and diamond-shaped signs, as they often indicate warning and danger. Finally, rounded shapes are reserved for friendly community notices for the most part, since we often associate circles with unity and security.
Now that you know what most sign shapes mean, you’ll understand an extra layer of meaning to each sign you encounter on the road, which is both fun and useful, isn’t it?
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