I’ve been looking for a while now for evidence that bike helmets are unequivocally good – so good that they ought to be enforced on a population. But what I keep finding instead is evidence like this*:
If I’ve got my Dutch right, and I think I have, the vertical axis is deaths per billion kilometres cycled and the horizontal axis is percentage of cyclists wearing helmets. The letters are, of course, the initials of countries. Bear in mind when you look at this that the Dutch (NL on the chart) ride 15 billion kilometres a year. That’s with a population of 12 million, folks.
In the last 18 months, Israel and Mexico City have repealed their helmet laws. Hong Kong refused to implement one because of the nasty chilling effect they have on cycling. Spain has a sort of half-baked law under which you don’t have to wear one in the city but you do if you’re riding between cities – except if it’s hot or you’re going uphill. Most other countries don’t have any helmet requirement and the few that do apply it only to children. And some of those don’t even enforce it. Despite this, there’s a marked lack of people dying in droves.
We got our helmet requirement as a result of an emotive, non-evidence based campaign. Here’s a graph showing the effect of the law on head injuries in NZ at the time it was implemented.
If helmets were effective you’d expect to see a big downwards rush in the red line showing head injuries from the time the helmet requirement was implemented, right? And yet the line is carrying on in much the same way as it already was.
Everything I’ve read points towards helmets being a bad idea for a population. The effect of mandatory helmet requirements is to reduce the number of people riding, and the number (or rather, the proportion) of people riding is the single biggest safety factor. More cyclists = more safe, and New York’s measurable experience is that improving cyclists’ safety makes the streets safer for everyone.
There’s reasonable evidence that wearing a helmet in a low-speed crash provides some level of protection. But there’s also evidence that wearing a helmet can make a crash involving a car more likely(!).
And bear in mind, folks, that helmets aren’t designed to protect you if you’re hit by a car. They’re tested by having a 5kg weight placed inside before being dropped from a height of one metre. The force of the impact is measured and that gives the safety rating. The best that I can say about that is that if you weigh 5kg and you fall one metre on to the centre/top of your helmet you’ll probably be OK.
Australia and New Zealand are the only two countries in the world that actively enforce helmet laws on adult populations. So do you think we’re safer than countries without helmet compulsion? To help you decide on your answer, let me ask you this: Is New Zealand’s road safety record so good that other countries are knocking on our door saying “How the heck do you achieve this great result? Tell us your secret, please!” or is it we who are looking to other countries for guidance?
I won’t tell you the answer, you can make an educated guess. But having considered the evidence I’ve gone right off helmets.
This post will be actively moderated. Grown-up, evidence-based, good-natured comments only, please.
Unfortunately I haven’t noted down the source of the first graph, which isn’t helpful. If you come across it let me know. See http://amsterdamize.com/documents/NVC2011_paper.pdf for the English version.