Whenever there are criminal cases involving moving vehicles (cars, snowmobiles, bikes, motorcycles, etc.), it may be necessary to determine if the headlamps, turning signals, and/or tail lights were “on” or “off’ and functioning correctly at the time of impact. Microscopic examinations of the filaments, bulbs, and lamp housing often give the scientist useful information about the general condition of the lamp. For example, in the pictures below, you can see a big difference between the filaments of two bulbs. In one picture, there is a clean brittle fracture of the filament. In the other picture, the filament is extremely distorted.