Many reports of automobile accidents in Ohio end with the phrase, “Police are continuing to investigate the accident.” What exactly does this sentence mean? How can police continue to investigate an accident after the vehicles, debris and victims have been removed from the scene? The answer lies in two topics: a thorough examination of the scene as soon as possible after the accident occurred, and an equally thorough recording of the positions of the vehicles involved to permit later analysis.Accident reconstruction is the process of obtaining, refining and analyzing information from a car crash. The information is derived from a number of sources, but the principal source of information comes from the vehicles, the crash scene and witnesses and drivers. The investigation of an auto accident is essentially the reverse engineering of the events that caused the vehicles to collide. A proper investigation usually includes the following:

• The positions of the vehicles at various times during the collision
• Evaluation of the scientific links in the chain of events
• A determination of the speed of the vehicles
• Direction of travel
• Calculation of time, speed and changing distance relationships between the vehicles
• Analyzing driver action
• Plotting the respective location of the vehicles as the accident progressed
• Evaluating contributing factors such as weather, road conditions, lines of sight
• Effects, if any, of alcohol or drugs on the drivers

The investigators work to gather as much evidence as possible from the crash scene and any witnesses. Skid marks are measured, the degree of malformation of the vehicles is determined. This information is then analyzed according to the laws of physics and engineering works that are accepted as standard references. Not all questions about an accident can be answered, but careful work by a knowledgeable engineer or physicist can provide a remarkably clear picture of how an accident occurred.