Wheelchair occupant studies

Abstract

The goal of this project was to improve transportation safety for occupants of motor vehicles seated in wheelchairs (i.e., to improve wheelchair transportation safety, or WTS), with an emphasis on drivers seated in wheelchairs. Investigation of crash and non-crash events involving one or more occupants in wheelchairs indicates that a primary reason occupants in wheelchairs sustain serious-to-fatal injuries is improper or incomplete use of lap/shoulder-belt restraints due, in large part, to interference by wheelchair arm supports with proper belt positioning. Efforts to improve frontal crash protection for drivers in wheelchairs resulted in a prototype seat-belt deployment system (SBDS) that provides components needed to complete the vehicle lap/shoulder belt for use in a passive mode while eliminating obstacles that interfere with maneuvering a wheelchair into the driver space. Sled-test evaluations and design improvements of a commercially available vehicle-anchored headand-back restraint for rear-impact protection of drivers in wheelchairs led to several design and material changes that improved performance and that the manufacturer can use to improve the commercial system. Results of sled tests and computer simulations of drivers in wheelchairs with and without steering-wheel air-bag deployments during a 48-kph frontal crash indicate that there is little basis for concern that advanced steering-wheel air bags will cause serious injuries in frontal crashes. Rather, steering-wheel air bags almost always reduce the risk of head, neck, and chest injuries. Deactivating steering-wheel air bags should only be considered when the driver in a wheelchair is positioned with his/her chest or chin 200 cm or less from the air-bag module during normal operation of the vehicle. Using a fixed upper shoulder-belt anchor point instead of the OEM seat-belt retractor will reduce driver movement toward the airbag module during pre-impact braking and may enhance safety for many drivers in wheelchairs by providing greater torso stability in their optimal posture. Safety Tip Sheets and a DriveSafe brochure have been developed to provide vehicle modifiers and other key stakeholder with information on how to provide safer transportation for occupants seated in wheelchairs. These are being made available on a new UMTRI website that provides a wide range of educational materials on WTS, including lists of wheelchairs, wheelchair tiedown and occupant restraint systems (WTORS), and wheelchair seating systems that comply with WTS industry standards. Additional work is needed to implement the SBDS into a commercial product and to continue efforts to educate key stakeholder groups with regard to best practice in WTS and their role in improving transportation safety for passengers and drivers seated in wheelchairs.