What is the difference between occupant-restraint belts and positioning or postural belts?

The term occupant-restraint system is borrowed from automotive safety field and means that the systems is designed and protect an occupant in a motor-vehicle crash. Few postural and positioning belts on wheelchairs have been designed to withstand the forces generated by an occupant in a frontal crash, which can exceed a 3000 lb force. Positioning belts should not be used as an occupant restraint in a motor vehicle, even if they look similar to a regular vehicle seatbelt. While WC19 and WC20 allow for positioning and postural belts on wheelchairs or seating systems to be crash tested and approved as occupant restraint belts, the types of anchorages and buckles typically used in these systems, such as sheet-metal screws through metal grommets and Velcro fasteners, would generally fail in the frontal-impact test. Such postural/positioning belts provided by the manufacturer of a wheelchair or seating system must therefore be labeled as “not for restraint in a motor vehicle.”

NOTE: In WC18, WC19 and WC20 the term “belt” is used to refer to a length of webbing material in occupant restraint systems and the term “strap” is used to refer to a length of webbing material used in a wheelchair tiedown system.