what is a stale green light

A stale green light is a term used in traffic terminology to refer to a green traffic light that has been green for a while, particularly if the driver has been in view of the light from a distance. Essentially, it means that the green light has been green so long that its about to turn red soon. When approaching a stale green light, drivers should anticipate that the light will change and be prepared to stop in a safe, controlled manner. A stale green light is a traffic light that is green when you first see it, thus you do not know how long it has been green. Safe, professional drivers are always on the lookout for stale green lights and make the necessary adjustments to stop safely.