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Each year in the United States, approximately 1 million collisions occur at signalized intersections, representing over 15% of all collisions and almost 9% of traffic fatalities. Engineers seeking to understand the roadway, vehicular, and driver factors related to these collisions are often asked to investigate and assess the traffic signal timing, right of way issues, and the signal indications displayed to involved drivers during the period of time leading up to and including the impact events. Until relatively recently, investigators were limited by the absence of any recording devices within the systems used for traffic signal phasing and timing. Accident reconstruction methods have long relied on the generalized signal phasing and timings programmed for that intersection by the responsible jurisdiction, combined with the vehicle dynamics calculated for the collision sequence in conjunction with witness testimony regarding signal indications and phase changes.

Numerous mathematical models for reconstructing vehicle-pedestrian collisions have been developed over the years utilizing common sources of physical evidence. As sources of video data recording proliferate, new sources of physical evidence are now available in some cases. This paper presents an expanded methodology for analyzing video footage of actual pedestrian collisions, including both static and dynamic camera positions. Each video was analyzed using digitizing motion analysis software to quantify the pre-impact and post-impact trajectories and speeds of the vehicle, the pedestrian, and the camera position for each collision. The relationship between vehicle speed and pedestrian throw distance has frequently been used in collision reconstruction to answer questions regarding vehicle/pedestrian impacts.

A number of methods have been presented previously in the literature for determination of the impact speed of a motorcycle or scooter at its point of contact with another, typically larger and heavier, vehicle or object. However, all introduced methods to date have known limitations, especially as there are often significant challenges in gathering the needed data after a collision. Unlike passenger vehicles and commercial vehicles, most motorcycles and scooters carry no onboard electronic data recorders to provide insight into the impact phase of the collision. Recent research into automobile speedometers has shown that certain types of modern stepper motor based speedometers and tachometers can provide useful data for a collision reconstruction analysis if the instrument cluster loses electrical power during the impact, resulting in a “frozen” needle indication.

Light bulb filaments of a vehicle involved in a collision can provide valuable information about the state of the vehicle's lights at the time of the impact. Through examination of bulb filaments for hot or cold shock, accident reconstruction professionals can gain information about which bulbs were and were not illuminated prior to the collision. A number of papers have been published on the general topic of hot and cold shock, however there is little published research about light bulb voltage and how it relates to filament distortion. Although a normally functioning electrical system of a passenger vehicle will operate at around 12-14 Volts, vehicles that have failing electrical systems or that have experienced damage to their electrical system may deliver less than full voltage to the bulbs. In order to help answer questions about vehicles with sub-optimal electrical systems, this paper focuses on the relationship between hot shock deformation and bulb voltage.