Citation

Shaw CG, Dalrymple G, Ragland CL. Annu. Proc. Assoc. Adv. Automot. Med. 1998; 42: 245-260.

Copyright

(Copyright © 1998, Association for the Advancement of Automotive Medicine)

DOI

unavailable

PMID

unavailable

Abstract

This study explored the injury potential associated with the use of steering control devices in frontal impacts. Steering control devices, an example of which is the spinner knob, are used by people who have difficulty gripping a steering wheel. These devices typically are clamped to the lower quadrant of the wheel rim and have projections that may extend out toward the occupant up to 14 cm and inward towards the airbag module up to 9 cm. A series of investigations were conducted to determine if the devices would: (1) be propelled off the rim by airbag deployment; (2) compromise airbag performance; and/or (3) cause injury to the driver. The investigations included frontal 48 km/h sled tests, quasi-static load tests, static airbag deployments, out-of-position static airbag deployments, and pendulum tests. Test subjects include the Hybrid III 50th percentile male and Hybrid III 5th percentile female anthropomorphic dummies and a male cadaver. The results indicated that there is little chance of the devices being thrown off the rim by airbag deployment and that the presence of the device had little effect on deployment or airbag performance. In addition, the presence of an airbag reduced the frequency and severity of impacts with the devices. The test results provided ample evidence of the potential of one of the devices, the "tri- pin," to cause severe injury to the chest upon impact. Steering control devices (SCDs) are used by drivers with reduced ability to grip the wheel rim. SCDs, essentially clamp- on handles, are commercially produced in a variety of configurations to suit the various needs of drivers with upper extremity limitations. A representative from MPD Inc., the largest United States manufacturer of these devices, estimates that 8-10,000 SCDs are sold annually, over 80% of which are spinner knobs (Lynn Ringdahl, personal communication, January 1998). The spinner knob is relatively small compared to the u- grip and tri-pin, devices that are designed for use by drivers with more substantial deficits. The tri-pin, designed to capture the hand and wrist, requires no grip strength. Both the u-grip and the tri-pin use vertical projections that extend from 11 to 14 cm perpendicular to the face plane of the wheel. The base of the tri-pin extends approximately 9 cm from the inner surface of the rim towards the wheel center. The series of studies reported in this paper investigates the potential for injury in a motor vehicle crash due to the presence of an SCD. SCDs were designed to maximize driver function and little or no attention was given to safety in crash situations. The development of SCDs predated the introduction of airbags. We were concerned that the devices, especially the larger ones, would: (1) degrade airbag performance either by tearing the bag or affecting its deployment; (2) be ejected from he wheel rim during airbag deployment; or (3) be impacted by the driver in a frontal collision. To our knowledge, only one prior study has examined SCD crash safety. This study, conducted by Gayle Dalrymple at the University of Virginia Automobile Safety Laboratory (ASL), consisted of static airbag deployments with seven SCD types (Dalrymple, 1996). Results of those tests indicated the potential for the tri-pin design to prevent proper airbag deployment. Interviews with several trauma surgeons and a literature search, primarily of the SAE Index and the Medline database, failed to produce information that would allow us to predict injury levels for the type of "blunt penetrating trauma" that appeared possible from impacts with SCD projections. Given the general lack of information regarding injury potential for SCDs, we proceeded with the series of investigations reported here. The ultimate objective of this ongoing work is to determine if these devices represent a significant threat to driver safety and, if so, to recommend strategies to reduce this risk.

Language: en