Traffic lights are a common sight in many cities and towns, and they are used to regulate the flow of traffic. The colors of a traffic light are typically GREEN, YELLOW'>AMBER, YELLOW, and amberyellow. GREEN indicates that it is safe to proceed, YELLOW'>AMBER indicates that the driver should slow down and prepare to stop, YELLOW indicates that the driver should stop if it is safe to do so, and amberyellow indicates that the driver should be prepared to stop.