Quote Originally Posted by Jonathan View Post
....it's the "restrain the head relative to the torso in a way that wouldn’t add injurious loads to the neck" that I refer to. Your device does not accomplish this.
I can't believe I'm wading into this, but Gregg's system *does* accomplish it as long as the torso and head are both restrained relative to the seat belts.

In other words, as long as the belts constrain the body, using the belts to also constrain the head accomplishes the same purpose.

I think Gregg would say that this assumption is totally valid and in fact the only way to approach it, because if the belts fail to constrain the body, then neither system succeeds.