Many newspaper and TV accounts of auto accidents in Prince William County and Manassas end with the statement that the accident is “still under investigation.” What, exactly, is meant by that vague phrase? Usually, it means that one or more forensic engineers are trying to understand the exact sequence of events that led to the accident. The forensic investigation has two basic purposes: identifying any mechanical or human element that may have caused the crash, and, if necessary, establishing legal liability for the accident.

Accident reconstruction

Another term for “forensic engineering” in this context is “accident reconstruction.” In plain English, reconstructing an accident means the use of standard rules of physics and chemistry to identify each event in the chain of events that comprised the accident. Forensic engineers usually begin their investigation by making a careful record of the accident scene. Many photographs and videos are taken to record the position of the various vehicles after the accident. Once these records collected, the investigators gather up the physical evidence from the crash scene. Such items may include pieces of the involved vehicles, tires, personal effects from occupants of the vehicles such as cell phones and containers for alcoholic beverages, and anything else the investigators think may be pertinent.

Using the laws of physics and chemistry

The next steps involve applying various laws of physics and chemistry to the evidence found at the scene. The length and direction of skid marks, for example, can help investigators determine the speeds of the vehicles in the moments just before the collision. Investigators often make scale drawings of the accident scene to help them establish the position of each vehicle at different states of the collision. The investigators can verify their laboratory calculations by comparing them to photographs and video tapes of the scene.

Essential tools for accident investigators are the results of researchers concerning the strength of the frames of different models, the resistance to skidding of various kinds of tires, a vehicle’s minimum turning radius and the coefficient of friction of various paving materials. This information is usually found in volumes of research data that have been compiled by other investigators on different accident scenes. Virginia has its own record and data collection branch known as the Traffic Records Management Reporting and Analysis Division.

DWI/DUI

An important aspect of any investigation is the determination of whether any drivers were under the influence of alcohol at the time of the accident. Investigators will look at the results of any field sobriety tests administered by officers in the field and any blood tests performed at a jail or hospital.

The long view

Many accidents involving death or serious injury are referred to the Virginia Multidisciplinary Crash Investigation Team for analysis. Many cities and counties within the Commonwealth of Virginia have their own crash investigative teams that involve officers who are undergo additional training and courses on crash reconstruction.  Another important use for accident investigation is by attorneys who have been retained to seek damages for one or more victims of the accident. Experienced accident attorneys will often hire their own accident reconstruction team to report on potential driver errors or mechanical failings that played a part in causing the accident.