Stop and Go Safety Signaling loading dock warning light devices help alert truck drivers and loading dock personnel to the safety status of docked or docking trucks. When a truck is safely parked and secured at the loading dock, the inside light is turned to green. This indicates to the forklift driver that it is safe to enter the vehicle. Any time the green light is on inside the building, the outside light is red. This indicates to the truck driver that he is not to move the truck. Once the truck is unloaded, the inside light is turned to red. This tells the forklift rider to stay away from the truck. At the same time, the outside light is now green, so the driver knows it is safe to move the truck. Best safety communication package for most loading docks.