You are disputing that blunt force trauma to your head causes injury? Or that having a barrier between your head and the point of impact prevents severity of injury? Which part exactly are you saying isn't true?

And actually, looking at actual accident statistics doesn't do a whole lot of good due to all of the variables involved (this point was actually made by the author and is about the only one that I agree with).

> You are disputing that blunt force trauma to your head causes injury?

No, I'm disputing that the majority of bike accidents involve blunt trauma to the head.

And looking at real data is the only way you can determine both the causes and results of real accidents, as opposed to artificial lab setups.