weight and height as Mr. Clark) to come into contact with the vehicle’s roof. Ibid; NR 61:Tab 2 at 27, 29. Based on his review and analysis of the movements of the surrogate diver during those tests (as reflected in photographs and film), Smith concluded that “even when properly restrained * * * the driver will come in contact with the roof rail as well as roof under static conditions with ample additional distance through which to flex the neck and produce the same or similar injury.” NR 47:Tab 3 at 5, 7. Moreover, Smith explained that in “a dynamic situation” as was involved in the actual accident (where the vehicle traveling at a high speed actually rolls over and impacts the ground during the rollover), the movement of “the restrained driver” off the seat will be even greater. Ibid.
In response to this evidence, Clark offered the expert testimony of James Lafferty, Ph.D., an engineer. NR 54:Exhs. 1, 3. Lafferty’s two-page expert report stated that “[i]f Mr. Clark’s lap belt had functioned properly, he would have been restrained from impacting the roof of the Honda * * * .” NR 54:Exh. 1A. Lafferty’s report offered the following explanation for this opinion:
From measurements made of Mr. Clark, I understand that his seated height is approximately 32 inches. The distance from the bottom seat cushion of the driver’s seat of the Honda to the top of the head rest (restraint) is 32 inches. Thus, he had about four inches of clearance between the top of his head and the crushed roof of the car. A lap belt, therefore, would have prevented his neck injury.
Ibid. When asked, however, at his deposition about “[w]hat evidence” he had to show “that the lap belt did, in fact, unlatch during the accident sequence,” Lafferty first testified that he was assuming the lap belt had become unlatched and had no opinion on that subject. NR 47:Tab 11 at 80 (“I didn’t address that question. I haven’t considered it, so I have no opinion on that.”). Later, in response to the request that he explain the “basis for saying that a properly functioning belt would [have kept Clark] from reaching