Many media reports of a serious motor vehicle accident end with the statement that “Police are continuing their investigation.” What are police continuing to investigate? Depending upon the nature and location of the collision, police may be looking for witnesses. In almost all such cases, however, police are attempting to “reconstruct” the accident.
How is this possible? Most post-accident reconstruction investigations are using the science of forensic engineering to understand exactly how fast was each vehicle moving, where did they collide and how did each vehicle end up at the spot where they were found by on-the-scene police. The results of such an investigation may seem like black magic, but in fact, accident reconstruction depends upon the careful application of well-established scientific principles.
Documenting the scene
The first job of the accident reconstruction team is to document the scene of the accident. This task involves photographing the entire scene to establish the location of each vehicle. Occasionally, videography is used to capture the entirety of a scene that occupies a broad swath of road and land near the road. Investigators also record other data, such as the size and location of skid marks, the nature and extent of the damage inflicted on each vehicle that was involved, and in accidents involving death or serious injury, the location of each person who was injured or killed. Police will also strive to locate, identify and interview every person who witnessed the accident.
Police will also collect physical evidence such as parts from each of the vehicles and damaged signs and traffic signals.
The accident reconstruction team will then shift the scene of the investigation to their laboratory. The extent to which the body of each vehicle was deformed by the collision is compared with reference works that use such data to calculate the speed of each vehicle. Finally, the engineers will use computer programs to calculate the forces involved in the accident. If needed, the investigation team will use computer graphics to create an animated reconstruction of the accident.
Accident reconstruction is not a technique limited to police departments. Attorneys representing people who were injured or the families of persons killed in such accidents can use accident reconstruction to present their case in court in order to explain the case to the jury.