The link between helmet laws and motorcyclists fatalities may seem intuitive and obvious, but now because of a study published in the American Journal of Surgery we have scientific proof that helmets save lives.

The study focuses around Michigan, which repealed its mandatory helmet law (thanks to help from the AMA) in April 2012, and has since had three riding seasons with a greatly reduce helmet-wearing requirement.

After the repeal, motorcyclists in Michigan can now ride without a helmet if they are over 21-years-old, have had their license for at least two years, and have at least $20,000 in additional medical insurance coverage.

Postulating that legislatures made a mistake in that repeal, the basic conclusions from the study are that the state has seen an increase in injury severity for motorcycles, a higher in-patient mortality for motorcyclists, and worse neurological damage for motorcyclists.

While those are all painful logical results, the numbers paint an even more grim picture.