Where was the Point of Impact?


Steven M. Schorr, PE ::::

Case Synopsis: Head-on, offset collision occurred between the left front of a westbound (WB) pickup truck and the left front of an eastbound (EB) passenger vehicle. Collision occurred while the pickup truck was negotiating a curve to the left, and the passenger vehicle was negotiating a curve to the right. Three occupants in the passenger vehicle all testified that the pickup truck “cut the corner” while negotiating the curve, came into the EB lane, and contacted their vehicle. Operator of the pickup truck testified that he was properly within the WB lane and the passenger vehicle came around the curve “too wide”, entered his path and struck him head-on.

Analysis: Physical evidence left as a result of the collision included: damage to the vehicles, points of rest of the vehicles, fluid from the vehicles left on the roadway, debris left on the roadway, and gouge marks near the centerline of the roadway. Damage to the vehicles established the principle direction of force [PDOF] that acted upon the vehicles as a result of the collision. Points of rest of the vehicles established the position the vehicles reached following the impact. Laws of physics defined how the vehicle would move based on the PDOF. Gouge marks occurred after the collision [when the damage vehicles dug unto the roadway following the initial impact]. Post-impact paths of the vehicles, as defined by the physical evidence, were pieced together. Data showed that the only sequence that was consistent with the laws of physics that allowed both vehicles to have ended up where they did and have sustained their documented damage was for the passenger vehicle to have crossed over the center line into the westbound lane. The laws of physics could not reconcile the physical evidence and the sequence of the collision as defined by the occupants of the passenger vehicle. That is, the vehicles would have ended up in different locations if the sequence proffered by the occupants of the passenger vehicle was accepted. It should be noted that the laws of physics define that a vehicle traveling too fast for a curve will slide to the outside of the curve. Movement of the passenger vehicle into the WB lane was consistent with the vehicle exceeding the critical speed of the curve and moving across the centerline [or in this case, the outside of the curve].

Result: The case went to trial. The jury concluded that the EB passenger vehicle crossed the centerline resulting in the collision.

Categories: Case Studies


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