A line-of-sight contact between a fixed point in the environment (a doorway, a corner, etc) or a
moving pedestrian and the forklift vehicle can be established using ultraviolet light (”AMSKAN”),
microwave radio frequency (Identcode, Tagmaster) or laser (NDC, Lazerway, Sick). The restrictions are that
line-of-sight might provide inadequate distance between vehicle and pedestrian at blind corners or in places
where the view is blocked. Microwave frequency will not travel well through water (incl. the human body),
which means that tags will require special solutions stitched into garments in order to be detected from any
angle.