(WHTM) — When driving on an interstate or any other major highway, you may see a sign directing you to a different city or another roadway. Most of these signs are green.

But, what or who made that decision to make these signs green? Well, there is actually a science behind these highway signs being green.

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Green is a reassuring color, according to builderspace.com. Being on an interstate or highway is already hazardous because of high-speed limits. Because of this, you have to keep your eyes on the road at all times.

The science behind this is that if highway signs, mile marker signs, or any other non-emergency signs were a different color, like red, our eyes would be darting all over the place looking at these bright-colored signs, making driving even more hazardous.

Green was chosen because of how it blends in with the surrounding environment. Green, unlike red, actually calms humans down. In a study that is linked on the National Library of Medicine’s website, it revealed that walking in a green environment included a significant reduction in heart rate values as compared to red and white conditions.

Other signs, like rest stop signs, or signs to national parks are usually blue and brown, respectively. These are also considered natural tones, which will guide you and not make you alert for a possible hazard.

These signs are made to tell drivers where they are in the most efficient way possible, without distracting them.

The color of highway signs has been around for decades. But, did you know that the font on these signs has changed within the past 20 years and that a Pennsylvania-based university was the one that studied the change in fonts?

I think I’ll save that story for another day.