Police - Accident Investigation and Reconstruction
The purpose of accident investigation is to determine what factors contribute to the cause of a collision and then through enforcement, education, and engineering apply those factors to reduce future collisions. A good Accident Investigator is able to interpret and analyze evidence collected at the scene of a motor vehicle collision. Based on available data from the collision scene the investigator will be able to perform complex speed calculations, involving vehicles that leave the road surface which may or may not become airborne speed calculations, and momentum and time position diagramming. Without accurate and complete investigation of serious collisions, remedial efforts are simply shots in the dark.

In general, the public that a police agency serves is more likely to be affected by traffic safety issues then violent crimes against property. There is a homicide committed every 21 minutes but there is a fatality due to a collision every 13 minutes. Also, there is a violent crime committed every 16 seconds but there is a personal injury accident every 10 seconds. In 1993 there were 40,114 people killed in collisions while 24,530 were victims of homicide. It is projected that collisions cost $137 billion annually as compared to $19 billion lost to victims of personal and household crimes.

Traffic related fatality and personal injury investigations identify who did it and why, but with a big difference. Since almost all collisions are unintentional, the factors that led to those collisions can be identified and then modified through enforcement, education, and engineering countermeasures. This leads to a reduction of those collisions, improved safety in the community and the very goal of law enforcement, police work with results.