Should airbags be deactivated for wheelchair-seated drivers?

Objective: Field data have shown significant benefit from driver airbag for occupant protection in frontal crashes. However, vehicle modifiers almost always permanently deactivate airbags for wheelchair-seated drivers. The objective of this study was to conduct sled tests and computational simulations to answer whether driver airbags should be deactivated for drivers seated in wheelchairs.

Methods: Five sled tests were conducted under a 48-kph 20-g frontal crash pulse all with driver airbag. Seat-belt fit (good, poor, and unbelted), airbag deployment time (proper and late), and occupant size (midsize male and small female HIII ATDs) were varied in the tests. The 2006 Chrysler Town-and-Country minivan was selected as the nominal vehicle environment, and a surrogate wheelchair with a docking securement system was used for all sled tests. ATD injury measures for the head, neck, chest, and lower extremities were recorded in each test, and were used for validating a set of MADYMO models. Parametric studies with a total of 28 MADYMO simulations were then conducted to investigate the airbag effects on occupant injury risks with varied occupant size, belt fit, and impact angle (0, 15, and 30 deg).

Results: The sled tests showed potential safety concerns for wheelchair-seated drivers with a poor belt fit or without a belt. Specifically, the unbelted midsize male ATD sustained high femur forces and the small female ATD with poor belt fit sustained high chest deflections. The parametric simulations showed that airbag generally improved the protection for wheelchair-seated drivers. It is especially useful for unbelted wheelchair-seated drivers, and is also helpful for reducing the head and neck injury risks regardless of the belt condition, occupant size, and impact angle.

Conclusions: This is the first study using sled tests and computational simulations to investigate the effects of airbag deployment on injury risks of wheelchair-seated drivers. Overall, the results showed little basis for concern that the energy of deploying a driver airbag in today's vehicles will cause serious-to-fatal injuries to drivers seated in wheelchairs. The results of this study therefore support the idea that driver airbags generally offer tangible safety benefits for a wide range of wheelchair-seated drivers in frontal crashes.