With more and more bicyclists hitting the streets every day, we should probably pass some sort of law requiring helmets, right? An article in Next American City Magazine questions this logic, pointing out that helmet laws decrease bike ridership — either because it leads people to think cycling is dangerous or, more likely, because fashion conscious cyclists won’t be seen dead in one — and this decrease in ridership makes things increasingly less safe for bikers.

But the results [of a helmet law in Western Australia] were disastrous. According to the Bicycle Helmet Research Foundation, immediately after the law went into effect, the state of Victoria, where cycling rates had been increasing dramatically over the previous 15 years, saw a 36 percent decrease in ridership. For every one teenager who began to wear a helmet, more than 10 others abandoned their bicycles. While 80 percent of Western Australian children walked or biked to school in 1977, that rate has plummeted to a measly 5 percent in 2009.

What’s more, when the Victoria helmet law took such a hefty chunk out of cycling rates, it ended up paradoxically decreasing cyclist safety. This is because one of the biggest determining factors of bicycle safety is not protective wear, but the number of other cyclists out on the road. In 2003 health consultant Peter Jacobsen published a widely read report that tracked this trend across such disparate locales as California, Denmark and the U.K. Even when cities within the same country or state were compared, the results bore out this fact.

One of the primary reasons helmet laws depress ridership is that they seem to imply that cycling is a dangerous activity. But this is not the case. According to a study published in 2006 by the British Medical Journal, cycling is not significantly more dangerous than either walking or driving. The study estimates that on average it takes 8,000 years of normal cycling to produce a serious head injury, and it takes 22,000 years to produce one death.

I definitely see why people wear helmets, though. Imagine if you had to transport a hard-drive full of your entire life’s files and memories — the only copies of all your artwork and photos and music and finances. Wouldn’t you put it in a protective case before bicycling across town? In any case, the argument here is not against helmets per se, but against helmet laws.

I remember reading about the Jacobsen study mentioned here years ago when it came out, which made the incredibly sane argument that the more people walk or bike, the more safe it is to walk or bike. Here’s a link to the abstract of the study, and you can get the PDF version of the whole thing there if you’re interested.