Accelerations and Shock Load Characteristics of Tail Lamps From Full-Scale Automotive Rear Impact Collisions

An estimated fifty percent of automobile accident fatalities occur at night. When investigating these accidents, the question often arises as to whether the lamps were on or off at impact. One approach to answering this question is to inspect the lamp for damage evidence that can be compared to research or previous investigations. Articles addressing automotive lamp examination can be found in the literature dating back prior to 1960; however, only a relatively few of these articles have incorporated experimental work. The articles that have experimentally studied the shock load characteristics of automotive tail lamps have: 1) based conclusions on acceleration data far removed from the lamps, or 2) have made assumptions as to what the “actual” accelerations are at the tail lamp itself. In order to gain insight into what accelerations, and associated shock load characteristics, are actually “seen” by tail lamps during an automotive collision, four full-scale, instrumented, rear impact crash tests were conducted. The results indicate that the accelerations at the directly contacted tail lamp housing can reach values an order of magnitude greater than those “seen” at the vehicle CG. Pre- and post-impact lamp condition comparisons were made for selected lamps. Comparisons were also made between lamps with respect to their location relative to the direct contact zone, as well as with respect to their filament state at impact (i.e., on or off).