Some jurisdictions have taken the step of banning cycling without a helmet. In Australia for example, it is now illegal even for children to ride around without a helmet. And in Australia, cycling-related deaths have fallen. But what’s intriguing is that cycling overall has also fallen, at a faster rate than cycling-related fatalities. In other words, the rate of cyclist death has increased. More worryingly, the rate of head injuries – which one might naively expect to be more directly affected by helmet use – has not fallen as a result of legislation, again implying that the rate has gone up. (See the links here.) Put another way, if you cycle in Australia, where cycle helmets are mandatory, you’re more likely to get a head injury now than before the law was changed.