The primary intervention for injury in children traveling in cars in Australia has involved the mandatory use of a restraint while traveling in a vehicle. This intervention has been successful as evidenced by high restraint usage rates by Australian children and substantial casualty reductions since the 1970’s. However casualty rates have been relatively stagnant over the last couple of decades. Currently more than 3,000 child occupants are seriously injured in Australia every year. There is a need to examine the scope for further preventing injury among restrained child occupants.

This thesis presents four interrelated studies examining the factors and mechanisms involved when Australian children are seriously injured while using some form of restraint in a crash. Methods used include retrospective medical record review, in-depth crash investigation and analysis of mass in-depth crash data. Both descriptive and nonparametric statistical analysis techniques, including those that allow for the control of potential confounders, were used.

Observations and results indicate there is substantial scope for further reducing serious injury in children traveling in cars in Australia. To realize this reduction there is a need to address the quality of restraint use by children through the development of strategies that not only encourage restraint use, but encourage the correct use of the most appropriate forms of restraint. There is also a need to address the protection provided by restraint systems and vehicles to child occupants in high severity crashes, and in crashes that involve impacts with fixed roadside objects such as trees and poles.