"he could have hit that window, his head could have snapped back very quickly, and he could be a quadriplegic today. "
I'm confused about why people think this-at that kind of velocity I don't think either head or helmet would have bounced off a piece of glass. I would kind of think that like a hard metal bullet vs. a rubber one, a hard helmet would penetrate even more forcefully foreward through the glass than a soft head, not bounce back. I tend to think if you're gonna get a spinal cord injury you'll get it helmet or no helmet, but brain injury of course should be much less frequent with a helmet. But I'm no scientist, and no one can really say what exactly would have happened in any one accident. The facts are that helmet wearers get fewer and less severe injuries overall than non-helmet wearers. I think you have to go with that stat, just like seatbelts, there are far more people injured and dead as a direct result of not wearing them than as a direct result of wearing them.
I don't know the answers. I have never gotten on a motorcycle. I was involved in sports at a rather high level for a couple of decades, and just never wanted to get my legs crushed or whatever other thing. It just seems a little silly to be out there on the roads with all the morons in the cars.
;-)