An important issue in many vehicle accidents is to determine if the vehicles lights were on or off at impact. It may be the brake lights, signal lights, back-up lights, or headlights that are at issue. Review of the literature indicates that analysis of halogen headlights ace not covered in the detail of other lights. This paper will evaluate halogen headlights.Many indicators used to determine if lights are on or off at impact do not generally occur with halogen headlights. The filament is structurally stronger, and the filament envelope is rarely broken during impact. Included in this paper will be a brief theory on differences between standard lights and halogen lights. Several case studies will be evaluated and conclusions presented to determine if a halogen headlight was on or off at impact.