Do the thought experiment where the front vehicle is a bus and a passenger is standing at the front of the aisle facing forward and wearing roller skates; do another thought experiment where everything is the same and the back of the minivan front seat is made out of a thin web of tissue paper; then re-evaluate your analysis.

But we agree that the post-hoc engineering by the jury and the courts makes no sense.

It seems to me that you see the human body to be composed of independent sections. The bottom half of the passenger would by thrown forward by the bottom part of the seat and the top part by the back of the seat. You ignore the fact that the passenger has a backbone and other skeletal members. The same is true of the child.

You are absolutely right when you say the the collisions of the heads would be a terrific head-butt. The child’s head might actually be stronger because of it’s shorter radius of curvature. That is how a bullet penetrates a skull. No one could contest that it was the collisions of the heads that killed the child. My claim is that the collapse of the back of the passenger’s seat is like an optical illusion. We need some calculations from the crash dummy guys to settle the matter.

The main problem with the case is the post-hoc engineering by amateurs. None of the judges would submit to dental work by a jury.

Through the back of the seat. Which, if it isn’t strong enough, and if the collision is hard enough, and the passenger heavy enough, will yield from the resulting several-thousand-foot-pound force.

Bill, the physics are pretty clear: the child in the rear seat can be secured in such a situation, the front-seat passenger will rotate backwards relative to the car, and the effect of seat failure can be devastating: it’s a high-speed head-butt, and an adult’s head is harder than a child’s. There is a lot that is wrong with the Flax case (for one thing, if the passenger was heavy enough, no vehicle seat would have survived such a high-speed collision, and the only reason we’re talking about the seat-back is because they were in a minivan–if Flax was in a smaller car, he’d be just as dead for different reasons; for another, there are very good safety reasons to have a seat-back yield) but no one contests the theory of how Flax was hurt.

Let’s first look at the passenger. The acceleration from the crash would have been transmitted to the passenger through the seat. The bottom of the seat would have done most of the work in accelerating the passenger. There was a pivot around the seatbelt and there would have bee a torque on the back of the seat. Some of this energy would have been absorbed by the seat breaking.

Now from the child. Had the child been secured to the rear seat, then the forces on the child would have been synchronized with the forces on the passenger and the relative positions, separation, would have been maintained. If the child was not secured, then the initial acceleration from the crash would not have been mitigated by the deceleration of the total mass of the vehicles. The child’s head would be a cannonball. In fact one great argument for securing children in automobiles, after protecting them, is protecting you from the cannonball effect.

I may have the situation wrong but I think you have the wrong image of the accident.

Car rear ended so that is driven forward by the impact. Child in seat is driven forward in seat along with entire car. Passenger in seat would have experienced that same except that the seat failed. Her body remained more stationary relative to the outside plane of reference but flew backwards relative to the car’s accelerating plane.

This still doesn’t make it the manufacturer’s fault. Had the rear seat been empty and the passenger seat reinforced, the passanger might well be suing over injuries caused by having the seat driven into her and snapping her neck.

these stories keep making me think of the Laryy Niven Short Story, “Safe at any speed”
http://variety-sf.blogspot.com/2007/12/larry-niven-safe-at-any-speed-short.html

The passenger’s head would had gone forward in the accident. It had to be that the child was not secured, and it was the child’s head, not the passenger’s head, that was the cannonball.

Would a Daubert claim be possible?