Green highway signs, also called guide signs, are everywhere, and we pass them by without much thought. But their design has ...

Red is used exclusively for regulatory road signs prohibiting doing something. So, a stop sign is red because you are prohibited from driving past it without stopping. “Yield,” “do not enter,” no left ...

Distance signs on the highway tell you important information, including how far you are from your destination, where the next exit is, or when to expect a rest stop. These signals aren't always ...