Flashing Red Lights: If a traffic light is flashing red, a driver must make a complete stop before the intersection or crosswalk. A flashing red light must be treated like a stop sign, and drivers should only proceed with caution after coming to complete stops. Flashing Yellow Lights: A flashing yellow light warns drivers to proceed with caution. Drivers should slow down and observe traffic carefully, and proceed only when it is safe to do so.