This is a bicycle helmet. According to the maker, it's "brainwear for smart people"

Over the last few years I’ve been progressively reviewing the various arguments for and against Australia’s mandatory helmet law for cyclists e.g.see herehereherehere and here (1).

Most of the arguments revolve around whether or not helmets reduce head injuries and whether or not the law deters cycling. But there’s one common non-instrumental argument I haven’t discussed before.

It’s the contention that, if cyclists are compelled to wear helmets, motorists should be too because they suffer more head injuries. A variation on this line of argument is that pedestrians should also be required to wear helmets since they too suffer head injuries (2).

My response in principle is yes, motorists should indeed be compelled to wear helmets, provided it can be demonstrated that the social benefits exceed the social costs.

Any activity where regulation would have a net social benefit is prima facie worth doing. There are many behaviours that would make us better off if they could be regulated successfully.

I suspect, for example, there would be real social benefits from successfully compelling middle-aged men to wear helmets when climbing ladders. The cost to the community in medical care and lost productivity from even the small sample of men I personally know who’ve come to grief on ladders while putting up decorations or cleaning gutters amounts to a small fortune!

But many behaviours are simply too hard to regulate so we cop the social cost. It might be, for example, that a proposed regulation is too hard to enforce; or it’s too inconvenient; or it offends too many people’s sense of what’s fair and equitable; or we think some behaviours just shouldn’t be regulated.

As a consequence many proposed regulations don’t get up even though they’d be socially beneficial.

One way of looking at the helmet law is to conclude that those who proposed it in the late 1980s and 90s simply got lucky. Their timing was perfect.

Broader economic and social changes were starting to undermine the traditional cycling base; and the structural forces that would drive the current cycling boom were still in their infancy.

If the law had never been introduced in Australia, I expect any proposal to introduce it now would get short shrift.

Even in Copenhagen today there are calls from a minority for a mandatory helmet law. The big difference of course is we already have it and it’s often much harder to get rid of something that seems innocuous to most of the population than it is to introduce something new.

The law in Australia might owe a lot to serendipitous timing, but provided the benefits exceed the costs it makes sense. The best strategy for those who oppose it isn’t to focus on inconsistency but to demonstrate unequivocally their claim that the benefits actually don’t exceed the costs.

And what about the idea of motorists wearing helmets? The reason there’s no law mandating helmets for car occupants is probably because there’re better regulatory solutions for protecting their heads.

The combination of seat belts and air bags, supported by primary safety technologies like stability control, achieves an acceptable outcome with considerably less inconvenience than helmets would impose.


  1. The mandatory helmet “law” refers to separate State and Territory laws that were introduced at various times between 1990 and 1992 – see Did the helmet law reduce commuting by bicycle?
  2. For the purposes of this discussion, I’m ignoring the question of whether motorists are as much or more at risk of head injury as cyclists after taking account of matters like relative exposure.