The effective restraint of vehicle occupants in a crash partly depends upon the ability of the seat belts to ride against the load bearing elements of the human skeleton. This is normally achieved through good positioning of the restraint belts over the bony structures of the torso and pelvis in a three point system.
The Belt-fit Test Device (BTD) is a mannequin that measures the placement of the restraint belts relative to the human skeletal landmarks. The scores are used with performance criteria that relate belt fit with the risk of severe injury to the thoracic and abdominal regions. The BTD can be used for driver and passenger seat restraint design evaluation and is referenced in a memorandum of understanding (MOU) introduced by Transport Canada for all passenger vehicles sold in Canada. An electronic version of the device, the eBTD, has been developed by Human Solutions Inc. for use with RAMSIS software and provides a simulation of belt fit for compliance of restraint systems under the MOU.