When a traffic signal malfunctions but still has power, it will often revert to an all-red flashing mode. When you approach a signal light that is flashing red, you must come to a complete stop (signals that are in flashing mode can return to normal operation at any time and without warning, even when repair workers are not present). The flashing red may change to a solid red, and drivers often fail to notice the difference, running the red light. Proceeding on a solid red light is always illegal and can lead to a deadly crash. Be alert, and make sure that the light is still flashing and that it is safe to proceed before entering the intersection.