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© 2003 Brian F. Schreurs
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So we thought we'd cast aside all the "it just makes sense" and "if just one life is saved" rubbish and find some real, hard numbers to evaluate the effectiveness of crash helmets, and then we thought it'd be extra fun to compare those numbers against other modes of personal transportation to see where bicycling fits in with the bigger picture.

In doing this, we've found several different ways to qualify injuries and fatalities. One way is to look at raw numbers, e.g., "28 people choked on apples last year." However, for the most part, we have ignored such figures as they are largely meaningless. There is no way to judge the significance of a raw number without some measure applied to it (e.g., the number of choking deaths each year, the number of apples safely consumed each year, or some other means of determining relative risk); we only mention them as sort of a grounding to put abstract rates into real-world perspective.

Instead, we've selected three rates of injury and fatality:

• ...per 10,000 vehicles: The number of injuries and fatalities are weighted against the number of registered vehicles to determine how many injuries and fatalities will occur per 10,000 vehicles. This, presumably, is of greater consequence if you happen to live in areas of dense traffic. However, these numbers cannot be considered entirely reliable because the number of registered vehicles does not truly reflect the number of vehicles in use. We suppose the theory is that reducing the number of registered vehicles will reduce traffic crashes, but this is based on the massive assumption that the vehicles being de-registered are regular-use cars and not just seldom-used beaters.

• ...per 1 million population: The number of injuries and fatalities are weighted against the size of the population to determine how many injuries and fatalities will occur per 1 million people. While these numbers have some validity simply from the huge sample size, they are not too useful in gauging an individual's level of risk, as each individual will always be exposed to a risk weighting of "1" (one individual) regardless of behavior -- whether a shut-in or a travelling salesman. Consider that, by this measure, walking is riskier than motorcycling. Nevertheless, this is the statistic most often quoted by bicycle helmet activists, as it is really easy to calculate.

• ...per 1 million miles travelled: The number of injuries and fatalities are weighted against the number of miles travelled by the population to determine how many injuries and fatalities will occur per 1 million miles travelled. This is the statistic most often quoted in car crash figures (when they're being honest and not just using "gory" raw numbers) and for good reason: it weights risk by exposure. If you drive 50,000 miles a year, using this method you are exposed to twice as much risk as someone driving 25,000 miles a year. This still isn't perfect, as travelling conditions greatly affect a traveller's likelihood of crashing, but for a general overview of risk this is the fairest model available.

	Pedestrian	Bicycle	Motorcycle	Car
Death Rates
per 10,000 vehicles	N/A	N/A	6.7	1.6
per 1 million population	16.9	2.5	11	12.9
per 1 million miles travelled	0.2	0.2	27.6	1.3
Injury Rates
per 10,000 vehicles	N/A	N/A	133	124
per 1 million population	280	453	210	987
per 1 million miles travelled	3.9	15	551	99

Look at that: before even factoring in anything else, the fatality rate for each mile on a bicycle is the same as each mile on foot. And the injury rates are stunningly low either way: four injuries per million miles versus 15. Fifteen injuries per MILLION miles on a bicycle! And the CDC says that only one-third of injuries are head-related, so the rate of injury that a helmet might help with is only FIVE injuries per million miles, once again essentially the same as taking a walk!

Fatalities don't even become whole numbers until five million miles on a bicycle! Heck, even riding a motorcycle doesn't look that bad in the big scheme of things at 28 fatalities per million miles, and cars seem positively vaultlike considering how many miles most drivers put on them.

But wait, there's more.

The federal government is really big on fatality statistics because they track them so carefully -- it's a lot easier to collect information about someone on the slab as they don't have any say in the matter. The Fatality Analysis Reporting System (FARS) records every traffic-related fatality in the country. Injury statistics, derived from the General Estimates System (GES), are considerably more vague because they use statistical sampling from incident reports. Because of this difference in reporting, discussions on the cause of accidents tend to revolve around the more reliable fatality data, and this is why we're going to use it -- it's not just because we like being morbid.

It turns out that alcohol is a major player in all fatalities, not just car crashes. Drunk drivers cause 40% of car fatalities; drunk riders cause 29% of motorcycle fatalities; drunk bicyclists cause 24% of bicycle fatalities; and drunk pedestrians (we are not making this up) cause 33% of pedestrian fatalities. Apparently, staying sober while trying to move, or not trying to move while drunk, are both excellent ways of improving one's odds of survival.

People in cars would do well to buckle up: 60% of fatalities are not buckled. But wearing a helmet isn't as effective for motorcyclists: only 47% are bare-headed. Motorcyclists also put themselves in greater risk of death when they leave the road (28% of fatalities are from hitting a fixed object) or riding without training (27% of fatalities had no license).

And on a bicycle, it doesn't pay to be a youngster: 21% of bicycle fatalities are children younger than 16.

Remove these high-risk groups from the fatality rates, and suddenly they look much different:

	Pedestrian	Bicycle	Motorcycle	Car
Death Rates
per 1 million miles travelled	0.20	0.20	27.6	1.30
without drunks	0.13	0.15	19.6	0.78
without any high-risk groups	0.13	0.12	5.45*	0.31*
actual 2001 W.Va. fatalities	28	3	21	376

* Note that these numbers are probably a bit on the low side, as it is entirely possible for one person to engage in more than one risky activity, such as driving both drunk and unbelted. But they still help to put bicycling in perspective.

We threw those actual fatality numbers in there as a reminder of what all these statistics mean to us here in West Virginia, where mountain biking is a very popular sport.

But wait, there's more!

We took the helmet lobby's own numbers for per-capita deaths and injuries, and compared them to other per-capita deaths and injuries:

	Death Rate	Injury Rate
from cancer	2,010	N/A
from pneumonia/flu	237	N/A
from poisoning	73.5	1,842
from falling	50.9	27,100
from suffocation	44.0	137
while walking	16.9	280
from drowning	14.8	28.5
while driving	12.9	987
while motorcyclng	9.8	717
on horseback	3.8	127
while bicycling	2.5	453
struck by lightning	2.0	8.0
while skiing	0.2	43

Nearly twice as likely to be killed by a horse, six times more likely to drown, 100 times more likely to die of pneumonia or the flu, than to be killed while riding a bicycle. More than twice as likely to be seriously injured in a car, and four times as likely to be poisoned, than seriously injured on a bicycle. And keep in mind, according to the CDC, only a third of those bicycle injuries are head injuries.

Too many numbers? There are two important points to take away from all this talk of fatality and injury rates:

1. On a per-mile basis, the odds of being killed or sustaining a serious head injury while riding a bicycle are about the same as the odds of being killed or injured while out for a walk.
2. On a per-capita basis, the odds of being killed while riding a bicycle are nearly the same as the odds of being killed by a bolt of lightning (this author has, in fact, been struck by lightning -- albeit indirectly -- so he is well aware that "extremely improbable" is not quite the same as "impossible"); the odds of sustaining a serious head injury while riding a bicycle are about half the odds of sustaining a serious injury while out for a walk.

   and a side point...

3. Being drunk really screws up your ability to do anything right.

Helmets save lives? Well, sure, occasionally they do. There are always a few freak accidents. Bicycling is so dangerous that you'd be crazy to ride without a helmet? Hardly. In the real world, biking is no more dangerous than taking the dog for a walk, and often even safer. But we're pretty sure that helmet manufacturers are enjoying this new trend immensely. We wonder what walking helmets will cost.

If someone built a radar detector that only saved drivers from a traffic ticket one time in five million, the outcry would be enormous. Yet here the helmet people are trying to characterize an inherently safe activity as dangerous, and making tons of money off the ignorance they're breeding, and this deception goes unchallenged because who can question "safety"?

For once we'd like to hear the helmet lobby say something like, "Hey, this activity is really, really safe, especially for sober adults. We've got the helmets if you consider yourself at high risk." Instead they sell millions of helmets by claiming the sky is falling. Is it any wonder some of us are skeptical of the altruism?

Of course, it's up to each cyclist to determine how his exposure to risk -- and tolerance for risk -- matches up with the level of risk for the general population. Frankly, we started this search for data expecting the numbers to be much higher than they are. But it turns out we're talking about a few thousand injuries out of 3,000,000,000 miles cycled every year. With odds like that we feel no more need for a helmet than we feel the need to strap a lightning rod to our shorts.

But then again, we don't bother playing the lottery either.