A red zone light projects a red line or arc onto the floor beside or around a forklift to mark a keep-out distance that pedestrians should not cross while the truck is working.
Red zone lights, sometimes called halo or side lights, mark the area around a truck where a pedestrian is at risk from the swing of the rear end during turns or from a load being handled. The line gives people a visible boundary rather than a vague instruction to keep clear. Some trucks combine a red line on the sides with a blue spot behind, and some halo systems light all four sides.
Like blue lights, red zone lights warn but do not detect. They depend on pedestrians understanding the line, they fade in bright light and on light floors, and the boundary they mark is a fixed distance that may not match how far the truck travels before stopping. They do not tell the driver anything about who is nearby. OSHA 1910.178 does not require them. Use them as one layer of a pedestrian plan that starts with separating people and trucks. The forklift warning lights guide compares strobes, beacons and projected floor lights.