DO HELMETS REALLY DO ANY GOOD?

Some insist that a bike helmet is worthless in a high-speed crash.  They argue, plausibly enough, that no helmet would keep a bicyclist's skull from being smashed if he slammed head-first into a solid object at 30 miles per hour.

But while it is true that your odds of survival are slim if you plow headlong into a utility pole at that speed, in the real world most bicycle mishaps do not involve direct frontal impacts, but falling or glancing blows.  In such accidents, most of the energy of forward motion is gradually dissipated by sliding or rolling after the initial impact.  The speed of the impact itself (usually hitting the ground) is typically about what one would experience from falling off a bike from a dead stop—less than 15 mph.  Under those conditions even an inexpensive approved helmet, properly fitted and worn, is capable of preventing or limiting head injury.

Of course, unprotected arms, legs, and collarbones do get broken in crash impacts.  And the "road-rash" produced by the subsequent sliding and rolling can be very ugly.  But these injuries are usually not fatal.  Scraped flesh and broken bones eventually heal; spattered brains do not.

Some people worry that wearing helmets will make them too hot on a summer day.  But in fact, by keeping the direct rays of the sun off your head, a helmet actually helps you stay cooler while riding, by keeping your head in its own little patch of shade.  Modern helmets feature multiple vents, providing substantial cooling at speed even when the ambient air temperature and humidity are relatively high.

WEAR IT RIGHT!

Even the finest bicycle helmet cannot protect your skull if it is poorly fitted or improperly worn.  A helmet works by spreading a concentrated impact force over as broad an area as possible, and to perform that function adequately the helmet's interior must be in firm contact with that broad area to begin with.  If your helmet is just flopping around on your head and not covering the parts which need to be protected, it obviously won't work very well when you need it to.

When buying a helmet, be sure you get the right size for your head.  Too small and it's uncomfortable; too large and it won't stay where it belongs; in either case it won't conform to the contour of your head and thus can't protect effectively.  If this is your first time shopping for a bike helmet, your best move is to visit a regular bike store, where the personnel are trained and experienced at sizing, fitting, and adjusting helmets.  They can help you be sure you're getting all the protection you're paying for by properly matching the helmet to your head.  (Department and discount stores also market good helmets, but their salespeople are usually not trained in sizing and fitting.  So you must provide the know-how and experience yourself, if you buy a helmet at K-Mart.)

Once you have a helmet that fits your head, you must adjust the straps to hold it in proper position.  When properly adjusted, the helmet should sit far enough forward that it covers and projects beyond your forehead, which is most vulnerable in a crash.  (Some people fancy that wearing a helmet on the back of the head makes them look "cool."  Actually, it makes them look stupid, since the helmet isn't protecting anything particularly vulnerable back there, and the money spent on it is therefore wasted.  Dumb!)

When the helmet size, fit, and position are correct, snug the straps enough to prevent the helmet's shifting about on your head.  Tightening might feel a little uncomfortable (but not painful) at first.  However, you get used to it quickly.

By the way, if you are buying a helmet for a child, do not buy one that is oversize, expecting him / her to grow into it.  If the kid happens to have a bad accident his first trip out (It happens!), and the helmet can't do its job because it's too big, he might never live to grow into it.  If you worry about getting his shoes the right size for his feet, you should give at least as much consideration to protecting his brain.

AN OPINION

As you might have guessed, I always wear a helmet while biking—as a matter of choice, not because some politician with too much time on his hands decided I should.  But as I see it, adults who feel they have nothing in their skulls worth protecting are probably correct, and should be free not to protect it—as long as they also accept full responsibility for the consequences.  People who refuse to take reasonable measures to guard their own safety should be obliged to pay their own medical bills.  Don't send them whining to me, in the form of higher taxes and insurance rates!