Originally Posted by mconlonx

Mainly? Laceration/tears, contusion, road rash. I expect a helmet help and protect when less than serious head injury might otherwise be sustained. I don't not expect injury mitigation to be greater than negligible. Measurable? Maybe, but I've so far not seen studies regarding less than serious head injury, so I can't say for sure, not being any kind of safety/medical/statistics expert.