Performance of seats with active head restraints in rear impacts

Voo, Liming; McGee, Bethany; Merkle, Andrew; Kleinberger, Michael; Kuppa, Shashi

Affiliations

¹Johns Hopkins University Applied Physics Laboratory, United States of America

²National Highway Traffic Safety Administration, United States of America

Abstract

Seats with active head restraints may perform better dynamically than their static geometric characteristics would indicate. Farmer et al. found that active head restraints which moved higher and closer to the occupant’s head during rear-end collisions reduced injury claim rates by 14-26 percent. The National Highway Traffic Safety Administration (NHTSA) recently upgraded their FMVSS No. 202 standard on head restraints in December 2004 to help reduce whiplash injury risk in rear impact collisions. This upgraded standard provides an optional dynamic test to encourage continued development of innovative technologies to mitigate whiplash injuries, including those that incorporate dynamic occupant-seat interactions. This study evaluates four original equipment manufacturer (OEM) seats with active head restraints in the FMVSS 202a dynamic test environment. The rear impact tests were conducted using a deceleration sled system with an instrumented 50th percentile Hybrid III male dummy. Seat performance was evaluated based on the FMVSS 202a neck injury criterion in addition to other biomechanical measures, and compared to the respective ratings by the Insurance Institute for Highway Safety (IIHS). Three of the four OEM seats tested were easily within the allowable FMVSS 202a optional dynamic test limits. The seat that was outside one of the allowable limits also received only an “acceptable” rating by IIHS while the other three seats were rated as “good.” Results also suggest that the stiffness properties of the seat back and recliner influence the dynamic performance of the head restraint.

Links

URL: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv20/07-0041-O.pdf

Cited Works (4)

Year	Entry
2003	Farmer CM, Wells JK, Lund AK. Effects of head restraint and seat redesign on neck injury risk in rear-end crashes. Traffic Inj Prev. 2003;4(2):83-90.
1990	Olsson I, Bunketorp O, Carlsson G, Gustafsson C, Planath I, Norin H, Ysander L. An in-depth study of neck injuries in rear end collisions. In: Proceedings of the 1990 International IRCOBI Conference on the Biomechanics of Impact. September 12-14, 1990; Lyon, France.269-278.
1993	Svensson MY, Lövsund P, Håland Y, Larsson S. The influence of seat-back and head-restraint properties on the head-neck motion during rear-impact. In: Proceedings of the 1993 International IRCOBI Conference on the Biomechanics of Impact. September 8-10, 1993; Eindhoven, The Netherlands.395-405.
2003	Kleinberger M, Voo L, Merkle A, Bevan M, Chang S-S, McKoy F. The role of seatback and head restraint design parameters on rear impact occupant dynamics. In: Proceedings of the 18th International Technical Conference on the Enhanced Safety of Vehicles (ESV). May 19-22, 2003; Nagoya, Japan.

Cited By (2)

Year	Entry
2009	Locke G, Veine E, Merkle A, Kleinberger M, Wing I. Influence of seatback content and deflection on FMVSS 202a dynamic response. In: Proceedings of the 21st International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 15-18, 2009; Stuttgart, Germany.
2008	Farmer CM, Zuby DS, Wells JK, Hellinga LA. Relationship of dynamic seat ratings to real-world neck injury rates. Traffic Inj Prev. December 2008;9(6):561-567.