Michael Griffiths

CHILDREN IN ADULT SEAT BELTS AND CHILD HARNESSES: CRASH SLED COMPARISONS OF DUMMY RESPONSES

Many children are still restrained in adult belts alone, even though an adult seat belt is not optimal for small occupants for whom a child restraint would be safer and more desirable. Therefore, a test programme was designed to investigate the impact responses of three dummies representing children aged 18 months, three years, and six years. The simulations were sled runs at a delta-V (change of velocity) of 48 km/h with accelerations of 27 g. The dummies were restrained in adult lap/shoulder, lap-only and child harness belt systems. Neck shear, axial tension and bending moments were rather higher with a lap/shoulder than with a lap-only belt. However, the lap/shoulder system minimised dummy head and upper torso excursion, head acceleration and pelvic accelerations. Lap belt loads, head accelerations, Head Injury Criterion (HIC) and chest accelerations were higher with the lap belt alone than with the lap/shoulder belt. The lap belt also permitted considerable excursion and head contact with the hard frame of the test seat, which affected HIC and neck loads. The lap/harness system gave generally the highest head and neck forces. (A) For the covering abstract of the conference see IRRD 899572.

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.

A COMPARISON OF ALTERNATIVE ANCHORAGE SYSTEMS FOR CHILD RESTRAINTS IN SIDE IMPACTS

This paper presents the results of a test programme comparing the performance of the CAUSFIX (originally known as CANFIX) and the Uniform Child Restraint Anchorage (UCRA) systems to the conventional Australian anchorage system of adult belt and top tether. Each anchorage configuration was subjected to both 45 and 90 degree simulated side impacts. The performance of the attachment systems was assessed using the TNO P3/4 dummy in both a rearward facing restraint and a forward facing restraint. Assessment was based on peak head acceleration and displacement. The results indicate that both the CAUSFIX and the UCRA system can provide improved protection for children in side impacts. The CAUSFIX system was found to offer the greatest potential for improvement. The results of the work are significant to the current debate concerning the proposed draft international standard for universal anchorage systems. (A) For the covering abstract of the conference see IRRD 899572.

Motorcycle fuel tanks and pelvic fractures: A motorcycle fuel tank syndrome

ABSTRACT Objective: Pelvic injuries are a serious and commonly occurring injury to motorcycle riders involved in crashes, yet there has been limited research investigating the mechanisms involved in these injuries. This study aimed to investigate the mechanisms involved in pelvic injuries to crashed motorcyclists. Method: This study involved in-depth crash investigation and 2 convenience-based data sets were used. These data sets investigated motorcycle crashes in the Sydney, Newcastle, and Adelaide regions. Participants included motorcycle riders who had crashed either on a public road or private property within the study areas. The mechanism of injury and the type of injuries were investigated. Results: The most frequent cause of pelvic injuries in crashed motorcyclists was due to contact with the motorcycle fuel tank during the crash (85%). For riders who had come into contact with the fuel tank, the injury types were able to be grouped into 3 categories based on the complexity of the injury. The complexity of the injury appeared to increase with impact speed but this was a nonsignificant trend. The pelvic injuries that did not occur from contact with the fuel tank in this sample differed in asymmetry of loading and did not commonly involve injury to the bladder. They were commonly one-sided injuries but this differed based on the point of loading; however, a larger sample of these injuries needs to be investigated. Conclusion: Overall improvements in road safety have not been replicated in the amelioration of pelvic injuries in motorcyclists and improvements in the design of crashworthy motorcycle fuel tanks appear to be required.