It turns out that mandatory helmet laws for bicyclists are largely peculiar to the United States, where the National Highway Traffic Safety Administration recommends that "all cyclists wear helmets, no matter where they ride," and just a few other countries. In cities like Melbourne, Australia, where helmet use is mandatory, such laws may be contributing to the dismal use of its bike-sharing program, contends Rosenthal.
"One common denominator of successful bike programs around the world - from Paris to Barcelona to Guangzhou - is that almost no one wears a helmet, and there is no pressure to do so."
While helmets can prevent serious head injury in certain types of crashes, Rosenthal says that such falls are exceedingly rare in "mature urban cycling systems. On the other hand, many researchers say, if you force or pressure people to wear helmets, you discourage them from riding bicycles."
"'Pushing helmets really kills cycling and bike-sharing in particular because it promotes a sense of danger that just isn't justified - in fact, cycling has many health benefits,' says Piet de Jong, a professor in the department of applied finance and actuarial studies at Macquarie University in Sydney. He studied the issue with mathematical modeling, and concludes that the benefits may outweigh the risks by 20 to 1."
He adds: "Statistically, if we wear helmets for cycling, maybe we should wear helmets when we climb ladders or get into a bath, because there are lots more injuries during those activities."