The Need for Enhanced Protocols for Assessing the Dynamic Performance of Booster Seats in Frontal Impacts

Objective: The primary objective of this work was to examine variations in the level of crash protection provided by different models of high-back booster seats in frontal impact. Secondary objectives included examination of the influence that specific belt positioning features have on the ability of a booster to achieve and maintain good seat belt fit; and the relationship between dummy loads, motion, and belt fit, both statically (pre-impact) and dynamically (during impact). Methods: Seventeen different models of high-back booster seats were subjected to simulated frontal impacts on a rebound crash sled. The TNO P10 dummy, instrumented to measure head and chest accelerations and targeted to allow head motion tracking, was used in these tests. Three high-speed cameras were used to record dummy motion. Associations between pre-impact seat belt geometry, the dynamic seat belt fit, and dummy response were examined. Results: Clear variations were observed in the level of protection provided by the booster seats tested. Specifically, there were variations in the ability to provide and maintain good seat belt fit. Only three of the seventeen booster seats provided good sash (shoulder) and lap belt fit during dynamic testing. All seventeen boosters had a “sash guide.” Sash guide type did not appear to influence the dynamic belt fit. However, the location of the guide and ultimately where on the shoulder the sash was positioned pre-impact did influence the dynamic sash fit. Anti-submarine clips (ASCs) that work to position the lap belt low on the abdomen were also found to maintain good lap belt fit during the dynamic tests. However, two booster seats without ASCs were also able to maintain good dynamic lap belt fit, although the mechanism of this behavior is less clear. Though there was a relationship between head excursion, head acceleration and the pre-impact static position of the sash belt (shoulder belt), there was no relationship between dummy response and the overall ability of a booster seat to provide and maintain both good sash and lap belt fit. Conclusions: Booster seats aim to achieve a good seat belt fit for children too small to use the adult seat belt. Variations in dynamic seat belt fit observed among these seventeen commercially available booster seats demonstrate the need for regulatory protocols that incorporate assessment of dynamic seat belt fit. With current technologies, visual examination of the seat belt during dynamic testing is the best method for assessing this performance.

[1]  David Paine,et al.  Revised assessment protocols and scoring methods for the Australian child restraint evaluation program , 2007 .

[2]  Thomas G. Molnar,et al.  A New Concept in Child Restraint Design , 1979 .

[3]  Matthew P. Reed,et al.  Comparison of Child Body Dimensions with Rear Seat Geometry , 2006 .

[4]  W. New,et al.  Standards New Zealand. , 2005 .

[5]  Claude Tarriere,et al.  Protection of children on board vehicles: influence of pelvis design and thigh and abdomen stiffness on the submarining risk for dummies installed on a booster , 1996 .

[6]  Jason Forman,et al.  Biomechanical response of the pediatric abdomen, part 1: development of an experimental model and quantification of structural response to dynamic belt loading. , 2006, Stapp car crash journal.

[7]  Heiko Johannsen,et al.  Development and assessment of a surface force abdominal sensor , 2007 .

[8]  Roger Biard,et al.  CHILD ABDOMINAL PROTECTION: PRESENTATION OF A NEW TRANSDUCER FOR CHILD DUMMIES , 1993 .

[9]  Lynne E Bilston,et al.  Geometry of rear seats and child restraints compared to child anthropometry. , 2007, Stapp car crash journal.

[10]  Kristy B. Arbogast,et al.  Evaluating Pediatric Abdominal Injuries , 2005 .

[11]  Julie Brown,et al.  High back booster seats: in the field and in the laboratory. , 2006, Annual proceedings. Association for the Advancement of Automotive Medicine.

[12]  D. Durbin,et al.  Belt-positioning booster seats and reduction in risk of injury among children in vehicle crashes. , 2003, JAMA.

[13]  Matthew P Reed,et al.  Improved positioning procedures for 6YO and 10YO ATDs based on child occupant postures. , 2006, Stapp car crash journal.

[14]  Claude Tarriere,et al.  ABDOMINAL INJURY RISK TO CHILDREN AND ITS PREVENTION , 1997 .

[15]  Hans Norin,et al.  Child Restraints in Cars - An Approach to Safe Family Transportation , 1979 .

[16]  Lynne E. Bilston,et al.  Spinal injuries in rear seated child occupants aged 8 – 16 years , 2007 .

[17]  K Weber,et al.  CRASH PROTECTION FOR CHILD PASSENGERS: A REVIEW OF BEST PRACTICE , 2000 .

[18]  Julie Brown,et al.  Improving child restraint design – upcoming changes in restraint standards and remaining challenges , 2007 .

[19]  Kristy B Arbogast,et al.  Recent trends in child restraint practices in the United States. , 2004, Pediatrics.

[20]  Schindler,et al.  Abdominal injuries, injury criteria, injury severity levels and abdominalsensors for child dummies of the Q family , 2005 .

[21]  John W. Melvin,et al.  Abdominal Intrusion Sensor for Evaluating Child Restraint Systems , 1986 .

[22]  Suzanne Tylko,et al.  Protection of Rear Seat Occupants in Frontal Crashes , 2005 .

[23]  J R Rundell.  Children Are Not Miniature Adults , 2000, Psychiatry.

[24]  D C Herbert,et al.  CRASH PROTECTION FOR THE SUB-TEEN CHILD , 1974 .

[25]  Kristy B. Arbogast,et al.  Abdominal Injury Risk for Children Seated in Belt Positioning Booster Seats , 2007 .

[26]  Stephen W. Rouhana,et al.  Assessing Submarining and Abdominal Injury Risk in the Hybrid III Family of Dummies: Part II - Development of the Small Female Frangible Abdomen , 1990 .