bikes a mainstream part of transport -- close to zero. One of the very interesting things about the Fishman et al paper that you mention is that they cite a survey of Melbourne Bike Share users (or non-users, more commonly) with a majority citing helmets as the deterrent. Despite this they don't mention helmets in their recommendations -- the person paying the piper is calling the tune I suspect. In Melbourne the Minister for roads is considering what to do about the bikeshare, as it approaches the end of the contract period. Freestyle Cyclists is calling on members (& everybody) to write to the Minister asking him to give an exemption from helmets as a trial. Then we can stop speculating about the reasons for the low usage, and get some good data on the safety of cycling with or without a helmet. @Luke -- I do wonder how structurally sound the helmets provided with the Brisbane system would be after getting soaked by the rain then baked in the hot sun, two types of weather Brisbane has plenty of. My guess is that the majority of these helmets would cease offering much in the way of protection after a few months of weather exposure, which if true goes to show the silliness of the entire concept of forcing people to wear them is. Cycle hire in london has been a sucess. However you could not just turn up and hire a bike to begin with, you had to register