The belt-fit test device (BTD) measures and assesses static seat belt geometry of automobile seat belts. It was conceived and developed by Transport Canada throughout the 1970s, 1980s and 1990s to address abdominal and upper body injuries that resulted from a mismatch between seat belt geometry and occupants’ anthropometric characteristics. When positioned on an automobile seat, the BTD indicates whether the lap and shoulder belts fall within specified bounds that have been established to minimize the risk of serious injuries to soft tissue and organs from belt intrusion.

Recently, work has focused on the development of an electronic version of the BTD using computer-human modeling techniques and computer-aided design (CAD). tecmath AG, creators of the RAMSIS 3D human modeling system, are currently developing an electronic BTD (or eBTD). In addition to providing a convenient tool with which to certify seat belt fit of current vehicle models, the eBTD will help designers assess seat belt geometry before a vehicle reaches production.