Wheelchair integrated occupant restraint system feasibility in frontal impact

Individuals with limited mobility and unable to transfer from their wheelchair into another seat, often use their wheelchairs as motor vehicle seats in transportation. Belt and docking type wheelchair securement systems fasten wheelchairs to the vehicle floor during transport. Upper torso and pelvic restraint systems are installed in motor vehicles to prevent wheelchair occupants from impacting the vehicle's interior during motor vehicle collisions. Commonly installed fixed vehicle mounted occupant restraint systems result in poor belt-fit and decreased occupant crash safety when used for an occupant population of varying height and using various wheelchair designs. Results from an investigation of individuals using their wheelchairs as motor vehicle seats during transportation affirm the need for an improved wheelchair occupant restraint system that is safe, comfortable, easy and independent to use.; Research in the automotive industry showed improved crash safety and user comfort with seat integrated occupant restraint systems. A concept wheelchair integrated occupant restraint system (WIRS) featuring a wheelchair mounted upper torso and pelvic restraint was constructed and evaluated using quasi-static and dynamic test methods. Frontal sled impact testing showed WIRS crash safety and occupant injury risk compliance with safety standards. A computer simulation model was built and validated based on frontal sled impact test data. A sensitivity analysis was conducted on wheelchair seating system and occupant restraint parameters using this computer simulation model. Multiple parameters such as reduced restraint slack and the inclusion of restraint pretensioners and restraint load-limiters reduce restraint loads and occupant injury risk. Wheelchair seating system design parameters such as seat stiffness, seat- to back joint stiffness and seat back recline angle affect occupant injury measures and wheelchair seat surface loads. The Quality Function Deployment (QFD) method was used to communicate user needs and technical requirements of a WIRS to the wheelchair industry and wheelchair standards development organizations. When developing a WIRS, Good Manufacturer Practice, ergonomic design and compliance with wheelchair safety standards were shown to be the central elements to ensure user lifestyle fit, user safety, product usability and user comfort.; Additional sled impact testing is suggested to confirm this study's findings. Future studies should examine WIRS usability, user comfort and esthetics. The present study shows feasibility of a WIRS providing wheelchair occupants with improved safety, comfort, independence and ease of use when securing themselves during transport in motor vehicles. The present study provides wheelchair manufacturers and wheelchair standards organizations with key principles to develop a WIRS that meets users' needs.