Many media reports about traffic accidents include or end with the sentence, “The cause of the accident is under investigation.” What, exactly, is being investigated in such cases? In basic terms, the investigators are trying to determine how or why the accident happened. Such investigations are also directed at determining which driver may have been at fault or whether the accident was the result of a mechanical failure.
Accident reconstruction is a highly specialized field of mechanical engineering. Most reconstruction experts have engineering or similar degrees. An investigation begins with a careful collection of information. Police usually complete some kind of Traffic Collision Report that contains their observations and measurements of the scene of the accident. If further investigation is required, perhaps to support the claims of parties to a law suit involving the accident, a private investigation firm will be summoned. Such firms usually have several engineers or physicists on their team.
The investigators almost always inspect the vehicles after the accident. If any vehicle was operated by a commercial enterprise, the investigators may look at maintenance records. Physical evidence may include skid marks and the degree of distortion in the body of one or more vehicles. Investigators often inspect the ground beneath a vehicle looking for gouge marks in the pavement to determine vehicle position and heading at the moment of collision.
Collision reconstructionists use a number of formulas to derive the velocity of the vehicles and acceleration and deceleration. Principal Direction of Force is a term that is frequently used to simplify the collision analysis.
Accident reconstruction is used for a number of purposes. Police departments and public safety agencies want to know if any of the vehicles suffered from mechanical failure. Persons injured or killed in an accident may be represented by experienced trial attorneys who understand the value of a thorough and specific investigation.