Steven M. Schorr, P.E.
Case Description:
A southbound Cadillac Escalade was attempting to turn left at a signal controlled intersection. While executing its left turn, the Cadillac was contacted on the right side by a northbound Ford pick-up truck. The Ford pick-up truck operator testified that as he approached the intersection, the already moving southbound Cadillac suddenly turned left into his path, not providing him with sufficient time or distance to avoid it. The Cadillac operator testified that he was not "already moving," and did not "suddenly turn" into the pick-up truck's path, but rather he was stopped completely at the signal, accelerated normally into his left turn and was struck. The Cadillac operator claimed he was within the intersection for enough time to allow the pick-up truck to easily avoid him.
Expert Analysis:
Both vehicles had airbags and both airbags deployed. The airbag module (The Cadillac's Sensing & Diagnostic Module [SDM] and the Ford's Restraint Control Module [RCM]) were downloaded for each vehicle. The downloaded data indicated that in the five seconds prior to airbag deployment, the Cadillac was decelerating from 30 mph to 15 mph. The SDM showed no indication that the Cadillac was stopped at any time in the 5 seconds prior to impact. The crush data and the RCM download of the Ford indicated change in velocity and "g" forces were consistent with the Ford was not traveling at, or above, the 35 mph speed limit. The SDM and RCM data were then correlated to other available physical evidence, including the damage to both vehicles, the points of rest positions of the vehicles and the point of impact position of the vehicles.
Result:
The SDM ["black box"] data from the Escalade indicated that the Cadillac did not stop prior to entering the intersection and as such, the testimony of the Ford operator, that the left-turning Cadillac was not turning for sufficient time and distance to be avoided was reasonable and credible. Further, the testimony of the Cadillac operator, that he stopped prior to accelerating through the turn, was not credible when compared to the "black box" data and the physical evidence. The RCM data from the Ford and the available physical evidence confirmed that the Ford pickup truck did not exceed the speed limit.
DJS Associates, Inc.
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Automotive Engineering
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Abington, PA 19001
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Posted by
DJS Associates, Inc.
at 9:43 AM
Division: Automotive Engineering
