When it comes to polarizing social issues, the choice of whether to wear a helmet while biking is midrange. It's below legalizing same-sex marriage, but above, say, the battle to digitize the nation's medical records.
In the behelmeted corner, we've got your mom, anyone who's seen or done something like the above helmet-cracking mountain bike crash, and professional cyclists who like their job as is. Most of the facts support their case. Helmet use reduces the risk of head injury by 85 percent, and head injuries are cited in the vast majority of cycling-related deaths. And if you live, head injuries are a bad, bad thing. Ever see the film Memento, where the guy looking for his wife's killer has to tattoo things on his arms to remember them? That's the afterparty of a head injury. Avoiding head injuries where possible is a sign of basic competency in adults.
As for the unhelmeted contingent, the reasoning turns fuzzy and anecdotal, abetted by the relative rarity of streetside brainings and by an abundance of excuses. You know the ones: People don't need them in Amsterdam or Portland! It won't work with this hairstyle/fancy clothing/hot weather! I just forgot it today!
But there's a subtler line of thinking regarding the "brain bucket." Some cycling advocates assert that pro-helmet information campaigns and laws mislead the riding public into thinking that they're covered on road safety simply by wearing a helmet. They say that the "ride with a helmet or not at all" approach alienates non-riders, and gives new riders a potentially terminally false sense of security. If you had to choose between learing about how to avoid getting hit by cars or a helmet, they say "ditch the helmet." Yet they also acknowledge you'll not have to make that choice, so do both.
Some respected figures even advocate not wearing a helmet, citing the role helmets play in today's culture of fear. Going lidless, they say, forces cyclists to ride more cautiously overall. (Note that this man lives in Copenhagen, whose name comes from an Old Norse phrase meaning "unimaginably slow and safe.") Nonetheless, there is research that suggests bicyclists who wear helmets are at higher risks of being hit.
Most of the time, I wear a helmet. Sometimes I don't. In those cases, I'm usually on my mountain bike, pretending that its slow beefiness will defend me against some sudden force. Maybe I'm just going a few blocks. Also, maybe I've got a nice outfit on, and I want to stay unencumbered for the night, and I forget how easy it is to lock it with my bike (threading your lock through the rear adjustment mechanism, mind you, not the straps, which thieves can easily cut).
Sure, critics of helmet laws seem justified in some theoretical sense. (Although their high-minded focus on safe riding techniques ignores chance accidents where a helmet might be life-saving.)
Principles are nice to have when biking, but they ignore the physics of what helmets do in practice. They're not some passive hedge against road scrapes. Helmets directly absorb the impact of a fall, so that your skull doesn't absorb it. They're meant to compress or even crack a little bit upon impact. Anyone who's ever gotten a concussion knows the sickeningly sharp surprise followed by the fear and confusion of dulled senses. Why tempt that feeling or worse? The crash's circumstances, your speed, and who is to blame are all background noise when the body's physics takes over. Imagine the tip of a bullwhip in mid-crack, fluidly concentrating its channeled energy into the final segment. In most crashes, that segment is your noggin.
With that in mind, I'd like to adapt Pascal's Wager for an era of red-light runners and trolley tracks: You gain more by wearing a helmet and never crashing than you gain by never wearing a helmet and crashing even once.
Without sounding like a Reagan-era "Just Say No" ad, I encourage the lidless to embrace the well-chosen helmet as a part of life. I'm not only talking about fashionable cityfolk, for whom wearing a helmet should be another welcome opportunity to accessorize. (I have many different jaunty cycling caps for wearing under my helmet.) Because kids under 14 are the most at-risk population, parents should know better. Fit kids' helmets in a way that doesn't make them look like dopes.
By the way, if you've ever crashed and hit the ground with your helmet, throw it out now and buy a new one -- it has served its purpose and won't work again if you crash. Same thing if you've had it for more than a few years or store it in the sun, as the foam will break down.
Digitizing medical records is a larger battle for another day, as is bicycling infrastructure and mode-sharing theories. Today, very easily, you can do your part to temper America's health-care costs and tame that pesky culture of fear. Statistics show injuries from bicycle crashes are getting more severe -- and such statistics are made of up humans, remember -- humans with soft, lovely treasure inside, a trove that's worth finding again and again.