The USA is very much a bike-unfriendly country with some very small regional exceptions, and any effectiveness should be placed in a regional context.<p>In absence of bike-lanes a helmet probably makes sense. What also <i>really</i> helps is to educate drivers and to shift responsibility to the drivers of cars in car-bike collisions. If there was one factor that made bike riding safer here in NL then I&#x27;d point at that one rather than bike lanes or helmets.<p>People are simply much more careful around bikes.