I have been riding motorcycles for 40 years and was relieved when the mandatory helmet law was repealed. I put my helmets away and hope never to wear them again. The reasons are simple. Helmets obstruct vision and create enormous noise from wind turbulence. Yes, helmets obstruct a rider’s vision and hearing. I have suffered great hearing loss from being forced to wear helmets for years. In addition, helmets that meet the Department of Transportation standards offer marginal impact protection at low speed and at highway speed offer zero protection. Trust me, at 70 mph a helmet is not going to protect you from injury in the event of a crash. That notion is just plain stupid.
If reducing injury to motorcycle riders is the goal, then do what Canada did. They made it a criminal act and imposed mandatory jail for hitting a motorcycle. The number of motorcycle accidents dropped dramatically overnight.
It would be interesting to see the results of a study about how many accidents are caused by helmets obstructing sight and how many deaths occurred from helmets being caught on something during an accident resulting in a broken neck to the rider.