The results are clear: bike helmets reduce the severity of head injuries but not the frequency of accidents or the percentage of head injuries caused by those accidents. Worse, the passage of mandatory helmet use laws have actually been associated with increased accident rates because they led to significant decreases in the overall number of bicyclists, undermining the “safety comes from numbers” reality, with particularly disastrous impact on bike share programs.
A good article that sums up my thoughts on bike helmets. Yes, everyone should wear them but not because of a law. It’s more important to focus on improved facilities and getting more people riding bikes.