How New Technology Has Assisted Accident Reconstructionists

As I take a moment to reflect back on our many years of performing accident reconstructions, I am astounded by the vast diversity of the reconstructions and how the methods may have evolved but the physics remain the same. By that I mean, 20 years ago, most cars did not have any crash data being recorded in a crash, and now almost all vehicles record some type of data within their airbag computer – Event Data Recorder (EDR). Though airbags were almost universally incorporated in US automobiles by 1995, even if the vehicle recorded crash data, the vehicle owner might not be able to easily obtain it or even know that the data was collected. Now, thanks to Federal Motor Vehicle Safety Standard (FMVSS) 563, if the vehicle records crash data, it must be accessible to the owner, and this information needs to be conveyed in the owner’s manual.

Going back 20 years again, there were no 3-D laser scanners to map accident sites or vehicle crush. We used hand-held tape measures and vehicle databases to determine bumper heights and various measurement jigs and fixtures and plumb bobs to get the proper crush measurements at the bumper height and maximum crush profiles. Also, we often used a computer program such as Excel to plot the crush profiles and then used the coefficients and equations developed by the National Highway Traffic Safety Administration (NHTSA) to determine a delta-V. Now we can perform a laser scan of the crushed vehicle and compare it to the database of an exemplar vehicle. This comparison can all be done while sitting at my computer. With this information I can determine just about any dimension that I desire. In the end, though, it is still measuring crush correctly and using the coefficients and equations developed by NHTSA and based on physics to determine the delta-V. That part has not changed.

Now, similarly, a 3-D laser scan of the scene can develop a realistic image, including photograph overlays, and obtain virtually any distance measurement with incredible precision. In the past if you didn’t get the measurement during your initial site visit, you either had to go without the measurement or re-visit the site. Also, at times the site could change (repaving, add/subtract/change the lane layout, etc.) so if you did not obtain a measurement or photo on your initial time at the site, it might be too late later. With a laser 3-D map of the site, this is much less likely to be an issue.

These are just a few of the ways that technology is assisting the accident reconstructionist gather data in a more efficient and cost-effective manner.

DONALD EISENTRAUT, BSME, P.E., ACTAR, is a mechanical engineer at ARCCA, specializing in vehicular accident reconstruction and forensic analysis of crash protection systems and components.