One accident reconstruction is worth 10,000 expert opinions. Forensic engineers gather evidence to recreate the crash scene via computer simulation. Source: Granite State Graphics

Additionally, climate records are scrutinized. Weather and road conditions can play a big role in crashes, even when dry and sunny. Dry asphalt road will have less traction if dust is blown onto it. Or, traction is significantly reduced if any wet or slick foreign substance is spilled onto sections of the road.

Drivers and maintenance personnel may be deposed by either side, and may be called to testify about safety training, maintenance practices, and a host of factors that may have affected the crash. These interviews may uncover a fleet practice that contributed to the crash. Therefore, forensic engineers will interview the driver, if possible, and other fleet personnel, especially in maintenance.

Other vital evidence to be examined includes electronic data recorders. New trucks have recorders that monitor throttle position, steering wheel angle, and rates of change of pedal movement, brake pedal, and steering. Recorders lock data into memory for a given number of seconds before and after the crash.

When the engineers are done, they can go to court with a virtual reality model of the crash. They can reconstruct the driver's actions, often with greater accuracy than the driver can recall.

In one case, after engineers presented a crash simulation, each witness stated that it did not occur as reconstructed. But when each was asked where they were, and the computer was programmed to present the scenario as seen from each witness's position, each agreed that the simulation was exactly what happened.

Forensic engineers are not cheap. If there is no personal injury involved, it may be better, or at least less costly, to settle the damages and accept the court's judgment. But when injuries or deaths are involved, your insurance provider may insist on hiring one.

— Paul Abelson is a former director of the Technology and Maintenance Council of the American Trucking Associations, a board member of Truck Writers of North America, and active in the Society of Automotive Engineers.