NCJ Number
217228
Journal
Journal of Forensic Sciences Volume: 52 Issue: 1 Dated: January 2007 Pages: 119-124
Date Published
January 2007
Length
6 pages
Annotation
This paper explains how investigators determined whether or not one car's headlights were on at the time of a two-car road accident, given conflicting claims on this issue by the parties involved in the accident.
Abstract
Based on an examination of one damaged and one intact headlight assembly, investigators could not determine whether the headlights were on or off at the time of the accident; however, investigators' consultation with Ford dealers (the car was a 1992 Ford Crown Victoria) found that the car's headlights could not be on without the parking lights also being on. This meant that if the parking lights were off at the time of the accident, so were the headlights. The examination of the right parking/turn light found that the turn filament was intact. This filament was shiny and did not present any glass splinters or tungsten oxide. Thus, it was possible to conclude that the filament was off at the time of the shock that broke the glass and was not turned on after the accident. The fact that the parking-light filament's diameter diminished toward the rupture and that there was tungsten oxide in great quantity on each side of the fracture indicated that the filament did not rupture due to a shock, but rather by burning in the air. Also, the absence of any glass bead on the filament was inconsistent with the filament being lit at the time the bulb broke. This was also supported by the absence of any significant distortion. A complicating factor in the investigation was the fact that the first-responding officer turned the headlights on and off to see if they were working. This suggests the importance of training first responders in evidence-preservation procedures at vehicle accident scenes. 10 figures and 8 references