On 1 July 1990, Victoria became the first Australian State to introduce mandatory helmet laws for cyclists. Within a few years, all Australian States and Territories also introduced the law. Australia and New Zealand are the only countries on the planet with national mandatory bicycle helmet laws.
Once the laws were introduced, cyclist numbers reduced by up to 40%. The reduction came mainly from those cyclists who prior to the law never wore helmets. The numbers have not recovered since. While numbers of cyclists have increased in recent years, they have been almost exclusively male and what might be described as "sports" cyclists.
Once the laws were introduced, in Victoria numbers of cyclists admitted to hospital with and without head injuries fell marginally. Importantly though, head injuries did not fall any more than non-head injuries.
In New Zealand, adult helmet wearing increased from 43% to 92%. There was no reduction in hospital admissions.
In all Australian States, there has been a steady decline in hospital admissions of all road users since the late 1980s. With cyclists, the introduction of mandatory helmet laws made no difference to that general trend.
We are the fattest nation in the world.
Obesity costs us $36b a year.
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My humble opinion is that studies to date are inconclusive. Some studies tend to point to helmets reducing injuries but as the studies themselves note, differences in exposure are very difficult to measure. I have not seem any conclusive evidence either way. If people wish to wear helmets, good on them. But the choice of others not to wear them should also be respected.
One thing that is abundantly clear to me is that the present way of marketing cycling in Australia (tights, space goggles, leaning over the handlebars, day-glo tops, helmets, funny shoes that make you walk like a duck) does not appeal to most normal people. It gives the impression of a specialist activity instead of normal everyday transport. It also gives the impression that it is somehow dangerous and requires special safety clothing and goggles. Cycling itself is not at all dangerous.
The figures speak for themselves. The introduction of mandatory helmet laws discouraged cycling and we have been paying for it ever since.
From time to time, State cycling bodies organise a special ride pitched just at women. They are often advertised in the State's newspaper. Invariably they are advertised with a picture of some women in the specialist gear smiling under their helmets. Go to any of the women in your workplace who you know do not use a bicycle as every day transport and ask them whether the picture encourages them to get on a bike. Then show them some pictures from Copenhagen Cycle Chic. Ask them whether they would consider a bike for short trips if it looked like the ones in the picture and they could wear normal clothes like in the picture and they had safe, separated cycle lanes going exactly where they want to go. There is a small chance the answer might be different.