Improving protection system for wheelchair-seated occupants in vehicle side impacts

Objective: Previous research on occupant protection systems for wheelchair-seated occupants focused on frontal impacts, while similar studies on side impacts are very limited. The objective of this study was to identify the major injury concerns for wheelchair-seated occupants in side impacts and develop restraint systems to mitigate such injury concerns.Methods: Seven sled tests in side impact conditions were first conducted at 30 km/h with a 24 g peak deceleration. An ES2-RE ATD and surrogate wheelchair base (SWCB) were used in all tests, which varied armrest design, width of the SWCB, and wheelchair tiedown conditions. These sled tests set up the baseline performance and provided validation data for computational models. A set of validated MADYMO models were then used to investigate the safety concerns and potential restraint solutions for wheelchair-seated occupants in side impacts. Simulations covered nearside and farside impacts, inboard or outboard D-ring locations, varied wheelchair locations relative to the side door, varied seatbelt anchorage locations, and a few Center Airbag To Contain Humans (CATCH) designs. Finally, another set of sled tests were conducted to demonstrate the effectiveness of varied CATCH designs for protecting wheelchair-seated occupants in farside impacts.Results: Simulations suggested that wheelchair-seated occupants might fall from the wheelchair in farside impacts, while in nearside impacts the seatbelt and curtain airbag can provide reasonable protection to occupants using wheelchairs. The CATCH design, a curtain airbag mounted to the roof centerline with tethers attached outboard of the wheelchair station, was effective at preventing the ATD from falling off the wheelchair. Results from sled tests to iterate CATCH parameters confirmed that the concept was effective at retaining occupants seated in wheelchairs under farside impact loading.Conclusions: This study is the first to investigate wheelchair-seated occupant protection in both nearside and farside impacts. The injury concerns identified in farside impacts and the CATCH design can potentially help improve the protection of wheelchair-seated occupants in side impacts in the future. The CATCH design has potential to improve farside protection for occupants in traditional seating.