Milton, Washington, 28 miles south of Seattle, repealed its bicycle helmet law in June. Portland never had a bike helmet law to begin with. Same with Paris, Amsterdam, and Rome.

Seattle, though: Helmet City. It’s been illegal to bike here without one since 2003. Bare your unprotected pate while pedaling within city limits and it’ll land you a $30 fine. You could argue there’s good reason for that. A 2011 study by the National Highway Traffic Safety Administration showed that wearing a helmet during a crash is 85 to 88 percent effective in reducing head and brain injury. 

Yes, the law significantly increased helmet use, which jumped in the downtown corridor from 82 percent, in 2000, to 93 percent in 2010. But had the city council consulted a widely cited study in Injury Prevention (released the same year the law went into effect)they might have voted differently. The researchers found that the number of collisions between motorists and cyclists is inversely related to the number of cyclists on the road: More cyclists and pedestrians means fewer collisions; the prevalence of cyclists makes motorists more alert to their presence.

So the key, say bicycle advocates like Tom Fucoloro of Seattle Bike Blog, is to make sure bike helmets don’t deter more bikers from getting out on the road. 

He says the helmet law, for example, is why Seattle, unlike other bike enclaves such as Denver and Portland, has yet to adopt a public bike-share system. Let the cyclists make the decision to wear a helmet on their own, he says, and chances are they’ll still wear one: Last year 80 percent of Portland’s riders were helmeted.

Officials in Milton found the same thing after its law was passed. “We haven’t seen any changes,” says Milton city administrator Subir Mukerjee. The helmet folks are still wearing helmets; the rebels still aren’t.

They’re just not technically rebels anymore.