So if they can help reduce injury, shouldn’t they be mandatory, just like motorbike helmets? Australia tried it in the early 90s and the result was a 15 to 20 per cent drop in the number of hospital admissions for head injuries. That would have been great, but it also reduced the number of cyclists by around 35 per cent. The hassle and, for teenagers, embarrassment of wearing one steered people away from bikes and towards public transport and cars. And that, counter-intuitively, could have been bad news for their health.  A recent study in the British Medical Journal showed that cycling has a positive health impact around 77 times larger than the potential for serious injury; essentially, there’s a small chance that you’ll come a cropper, but a very large chance that you’ll reduce your likelihood of suffering mental illness, heart disease and obesity. That means the laws were hugely counterproductive; they reduced cycling injuries, but only by reducing the number of cyclists, and those people then became more likely to come to some other kind of less-dramatic and tangible harm. Clearly, if this was an acceptable approach then we could easily slash injuries by 100 per cent simply by banning bicycles.  The CTC, the UK’s largest cycling charity, has long argued against mandatory helmet laws for a similar reason. It claims they would make cycling seem more dangerous than it actually is, putting people off. “The evidence on this question is complex and contradictory, providing as much support for those who are deeply sceptical of helmets as for those who swear by them,” it says.  Then there’s the problem of enforcing new laws. In the first year after the Australian State of Victoria made helmets mandatory there were 19,229 Bicycle Offence Penalty Notices issued. Do we want to tie up that much police time on a crime which has no negative impact on a third party? South Africa made helmets mandatory, then couldn’t agree on exactly how to enforce it, so never did.  There's even evidence that wearing a helmet can put you at more risk. A 2006 study by Jeff Brewster from the University of Bath found that drivers passed closer to cyclists wearing a helmet when overtaking than they did those without them. The driver's subconscious sees them as less vulnerable and therefore less worthy of a wide berth.  It’s undeniable that mandatory safety devices such as motorbike helmets and seatbelts in cars have been lifesavers on a huge scale. But neither had the same potential for harmful side-effects: dissuade motorcyclists from riding and they’ll buy a car, which is actually far safer (if less fun). Meanwhile, there is virtually nothing that will discourage drivers.  Personally, I believe that wearing a helmet has more pros than cons, even though cycling is not as risky as many would have you believe. But there are those out there who would rather not ride than be made to wear a helmet, and for that reason the idea is a non-starter.
Bare-headed cyclists are often branded reckless and there are regular calls   for helmets to be compulsory, as politicians in Jersey are currently   demanding. But is it a practical way to keep riders safe?