Robert T. Lynch, P.E., Principal Collision Reconstruction Engineer

For multi-vehicle collisions, which often occur on limited access highways in poor weather / roadway conditions, the typical questions that are asked of the reconstructionist are which vehicles came in contact with each other and when?

The reconstruction engineer generally starts with evaluating the points of rest and damage to the vehicles. Then, any and all electronic data from the vehicles should be gathered and evaluated, including event data from the Airbag Control Module (ACM) of a passenger vehicle or the Electronic Control Module (ECM) of a commercial vehicle. DashCam and GPS data from commercial vehicles are also becoming more prevalent.

Even if a commercial vehicle is only equipped with a GPS tracker for basic fleet management purposes, instead of one that also records sudden deceleration data from a hard-brake or collision event, this information is still important to secure for the engineer to evaluate when that commercial vehicle arrived to the pile-up relative to the other vehicles. Specifically, electronic logs are tracked via GPS and store a data point at regular intervals or whenever a vehicle comes to rest (i.e.- after a collision). The time of the stop is recorded from a universal GPS clock. When multiple commercial vehicles with GPS data tracking are involved in the pile-up, this data can be evaluated to figure out the order that each vehicle arrived, as the time between the various GPS-based systems will be synced.

Robert T. Lynch, P.E., Principal Collision Reconstruction Engineer with DJS Associates, Inc., can be reached via email at experts@forensicDJS.com or via phone at 215-659-2010.