Alert latency is the time between a hazard occurring, such as a person entering a forklift's detection zone, and the safety system delivering a warning or slowing the truck.
Latency adds up across the chain: the sensor’s update rate, processing time on the device or server, communication with the truck or the wearable tag, and the time for a light, buzzer or brake command to act. While all of that happens, the forklift keeps moving. Then the driver or pedestrian needs time to react, and the truck needs distance to stop. OSHA 1910.178 requires that a truck be operated at a speed that lets it stop safely under all travel conditions, and latency eats into that margin.
Buyers should ask for end-to-end latency measured from detection to alert, not a sensor specification, and should ask how it changes when many tags or people are present or when the network is busy. Test it in a pilot with the truck at its normal speed. Processing on the vehicle usually responds faster than a round trip to a server. Latency and detection zone size have to be set together. The collision avoidance page covers how response time affects slowdown.