Last year my infant daughter came down with a potentialy fatal blood infection. So I've spent 3 weeks in the Pediatric ICU. In the ICU was my daughter, 1 car accident kid, and 10 other beds full of 8 ATV accidents and 2 golf carts.
Not a single moto injury. These kids didn't have broken limbs, they had crushed spleens and livers. As in Moto, the most serious injuries result from body-machine contact. These things weigh as much as a refrigerator and they will screw you up.
Of course a couple of the injuries were the kids with no helmet, oh well. Their parents should be locked up.
Anyway, I've seen it first hand. So if anybody gives you any four wheeler propaganda, have them stop by the local Pediatric ICU. The kids will be waiting for them.