Traffic light on yellow with sky and trees in background. - Ktsimage/Getty Images Ah, the yellow light. You know, that signal that is supposed to let you know to slow down as you approach the ...

Red and green traffic lights have been around since the 1800s, when British traffic officers used to rotate gas lamps that burned red and green to control the movement of mostly horse-drawn vehicles.

The idea of a fourth traffic light has gone viral online, with several reports claiming that a white signal will soon join the familiar red, amber and green at road intersections. The reason, ...