Contextual Cycling

Responding to the Wall Street Journal article on why the Dutch don’t wear helmets, Bikes Can Work nails it.  The Dutch don’t wear helmets because, he writes, “they have the world’s safest streets.”  The incidence of injuries and fatalities is so low there that the benefit of adding helmets into the mix would be hard to measure.  It’s one place, in fact, where requiring helmet use might actually cause people to bike less.

Photo credit: Amsterdamize.com

BCW’s insightful post is an example of what I call contextual cycling.  Most of the typical arguments for and against helmet use–which you’ll find perfect examples of in the comments under the WSJ’s story–rely on either a misunderstanding of facts or personal anecdotes as a substitute for true evidence.  Context is rarely a factor.

Take this comment from beneath the WSJ story:

Even motorcycle helmets only reduce the risk of head injury by about 20%, according to US statistics. Now compare a motorcycle helmet to a bicycle helmet. Bit of a difference, huh? Nonetheless, the bicycle helmet mongers often claim an 85% reduction. Maybe motorcyclists should start wearing bicycle helmets…or maybe the helmet mongers are blowing smoke.

If bicycle helmets reduce the risk of serious injury by 85%, it’s probably because most biking happens at such slow speeds that the risk of injury is low relative to motorcycles use.  Motorcycle accidents most likely happen at speeds of at least 55 miles per hour, and even the best helmet may not be enough to prevent serious head trauma at such high speeds.  (I’ve worn a motorcycle helmet, but I still don’t think I’d want Juan Uribe swinging a bat against my head.)  Plus, bike riding occurs in a variety of locations–city streets, but also parks, bike paths, sidewalks, and quiet cul de sacs–that are safer, generally, than where motorcycles can be found almost exclusively: on streets and highways.  Again, it’s all about context.

Then there’s this comment, a perfect example of confusing one’s personal experience with facts:

In 200,000 miles I’ve hit my head twice, neither time serious although I needed stitches once. This is all the proof I need that helmets are not necessary.

One could probably point to lifelong smokers who never develop lung cancer, but you’d be hard pressed to find doctors who would trot out such people as an example of why smoking is okay.  We all know terrible drivers who never get into an accident.  Comments like this represent a terrible misunderstanding of black swan theory.  Just because the probability of some event is low, or, more importantly, perceived to be low, that is not a reason for it not to happen.  (You hear this reasoning when it comes to driving and talking on a cellphone: how can it be dangerous if I can do it just fine?)  This commenter may live somewhere where traffic is light or drivers expect to see bikes on the road, but he also may live in New York and just be lucky.  There’s no way of knowing.

What I loved about BCW’s post–and Amsterdamize’s tweets on the subject–is that it takes in the full context of where the cycling occurs as a basis for whether or not helmet use matters.  Imagine having a discussion about jacket use that failed to consider where a jacket wearer lives.  Yeah, jackets keep you warm, but in Miami you might not need one for more than one or two days a year.  Context, more than any single study or personal example, is the best way to talk about cycling.