At first glance, traffic lights are stunningly simple: green means go, red means stop, and yellow means it’s about to turn ...

The yellow light didn’t enter the scene until the 1920s. William Potts, who was a police officer in Detroit, is credited with designing the first three- and four-way colored traffic lights.

According to the Florida Department of Transportation, if a traffic light is flashing red, come to a complete stop an treat it as if it were a four-way stop sign.