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Most accident reconstructionists realize that valuable information about a collision can be obtained from evaluating light bulb filaments. However, few fully understand the scientific phenomenon involved, and little research has been conducted in recent years. This study presents an applicable representation of realistic automobile collisions. In addition, the study takes into account the effect of used/aged bulbs and determines how effective filament stretch analysis can be used and under what conditions such analysis should be avoided. An innovative duration sensitive light bulb acceleration apparatus was used to determine if a consistent threshold Delta V exists that can be used to assist in the determination of impact severity.

The concept of brake dive is not new and most drivers are aware of this phenomenon. However, no known data is available to quantify the amount of change in vehicle height during braking. Often investigators involved in under-ride/over-ride collisions or relatively low speed collisions are faced with questions such as, “How much does the front bumper dip during braking?” or, “Is it likely that the relative bumper height mismatch is due to pre-impact braking?” This paper will provide the results of field testing aimed at providing answers to these and associated questions. The study will also review the factors that affect brake dive and the parameters under which these factors can be determined or be reasonably estimated. We consider how these factors can be used to predict the amount of change in bumper height.