The effect of pre-impact braking on the performance of child restraint systems in real life accidents and under varying test conditions.

This study compares a sample of approximately 900 real-life accidents with dynamic tests using a fully instrumented TNO P-3 dummy, in order to describe the effect of varying degrees of pre-impact braking. Altered test conditions, in particular the forward shift of seat belt anchorage points, are evaluated. It is concluded that pre-impact braking has little effect on horizontal head excursion and chest deceleration. Pre-impact braking does however reduce neck loads, resultant head deceleration and Head Injury Criteria (HIC). Reducing the excessive head excursion observed in vehicles with extreme forward anchorages may well require replacing automotive seat belts with a new interface for child restraints. (A)