The WIBU is fully called: "Waarschuwings Installatie Bellemerend Uitzicht", which means: "Warning System Obstructed View". The WIBU is a system that uses light signals to show people if there is a train approaching where they aren't able to see if there is a train approaching. The WIBU system uses mostly light signals with two white lights. The lights start flashing when there is a train approaching. If there's no train approaching, the lights won't flash.