A collision avoidance system detects a person or vehicle in a forklift's path and acts on the truck itself, by limiting speed or braking on compatible forklifts, rather than only warning the driver.
The difference between warning and avoidance is the intervention. A proximity warning system tells people about a hazard; a collision avoidance system connects to the truck’s controls, usually through the CAN bus or a speed-control interface, and reduces speed or stops travel when a detection zone is breached. In the hierarchy of controls this sits closer to an engineering control, because it does not rely entirely on the driver’s reaction.
Intervention only works on forklifts that can accept a slowdown command, so mixed and older fleets may get warnings on some trucks and slowdown on others. Sudden braking with a raised load can create its own hazard, so slowdown profiles need to be set per truck type and load. Ask what triggers an intervention, how quickly the truck responds at its real top speed, and what the driver can override. These systems reduce the risk of collisions; none makes them impossible. The collision avoidance page covers how active systems differ from warnings.