Sunday, October 18, 2009

Are you safe, stupid, or selfish by wearing a motorcycle helmet?

I ran across an interesting study titled, "Donorcycles: Do Motorcycle Helmet Laws Reduce Organ Donations?"[1] which argues that organ donations due to motor vehicle fatalities increase by 10 percent when states repeal helmet laws, and that every death of a helmetless motorcyclist prevents or delays as many as 0.33 deaths among individuals on organ transplant waiting lists.

The article also contains many interesting facts about motorcycling and the reasoning behind mandated helmet laws -- at least where they exit, for not many states have such laws: "Currently, 20 states and the District of Columbia require all motorcycle riders to wear helmets, and 27 states have partial coverage laws that typically mandate coverage for all riders age 17 and younger.6 Illinois, Iowa, and New Hampshire do not require any riders to wear a helmet."

Suppose you live in a state that had helmet laws and repealed them. Would you continue wearing the helmet? Well, a betting man would have trouble making money off you either way, since "several papers using single-state data find consistent evidence that the percentage of riders wearing helmets decreases from nearly 100 percent under universal helmet laws to roughly 50 percent when helmet laws are repealed." If you do wreck, the data on helmet protection is pretty convincing: "
Using [a] within-vehicle approach, [it was] found that helmets reduce fatality risk by 34 percent. Similarly, a recent meta-analysis found that helmets reduce the risk of death by 42 percent and the risk of head injury by 69 percent. A related literature estimates the effects of helmet laws on state-level fatality rates. Estimates based on within-state variation in fatalities and helmet laws over time suggest that universal helmet laws reduce per capita fatalities by 27 to 29 percent relative to states with no laws and by over 20 percent relative to states with partial laws"
I suspect the reason most riders forego a helmet is they just don't think they will have a wreck. Actually, I think there is something to this excuse. For example, there are well over 4 million register motorcycles in the U.S., and only around 5-6 thousand people will die in a crash in a given year. On average, only 12-13 motorcyclists die a day.[2] So, of all the millions of motorcycle trips happening per day, only a dozen or so of them are going to die on that day? Actually, those are extraordinarily good odds in favor of the person not wearing a helmet, at least that they won't die.

But what about injuries? I didn't immediately find statistics for this, but in Calif. it looks like the deaths to injury ratio is 1:22. So a reasonable per day injury rate would be around 270 or so. Again, extraordinarily good odds on any given day that a helmet-less rider climbs on a motorcycle. (Interestingly, while I consider this a statistically rational defense for not wearing a helmet, I myself am so irrationally risk averse that I wear one anyway.)

There are also "substantial differences across gender as regards donors and death rates. In every year, men account for roughly 90 percent of all motorcycle fatalities but only two-thirds of deaths in other types of vehicles," which is not too surprising, given even a casual glance at riders out the car window, or at a local bike showroom on Saturday mornings. Yes, there are more men riders, and men are far more prone to taking risks; but still, the study notes, "helmet laws decrease motorcycle fatalities roughly proportionately for men and women."

With four million registered bikes, there certainly are lot of motorcycle riders out there[3] But what if there were absolutely no mandated helmet laws? Among the conclusions of the study: "Estimates imply that nationwide elimination of helmet laws would increase annual organ donations by less than one percent." I found that surprising. Of course, if all states had opt-out organ donation laws, instead of opt-in laws, I'm sure there would be a much larger effect, but then donations via motorcycle casualties still probably wouldn't be significant in that case, since there would be many more organs available for transplant anyway.



[image] "This was worn by Dave Swisher who, at last count, has north of 1 million miles under his belt." melm00se July 31, 2009 (Accessed October 18, 2009)

[1] Stacy Dickert-Conlin, Todd Elder and Brian Moore "Donorcycles: Do Motorcycle Helmet Laws Reduce Organ Donations?" (.PDF) Michigan State University June 10, 2009 (Accessed October 18, 2009)

[2] L.A. Motorcycle Lawyers - Detailed Motorcycle Injury Statistics (Accessed, October 18, 2009)

[3] There are some interesting, if unsettling trends in motorcycle fatalities: "Motorcycle crash-related fatalities have been increasing since 1997, while injuries have been increasing since 1999. More than 100,000 motorcyclists have died in traffic crashes since the enactment of the Highway Safety Act and the National Traffic and Motor Vehicle Safety Act of 1966. " (source: National Highway Traffic Safety Administration: Motorcycle Safety Program.) As the NHTSA graph shows, people apparently born to be wild again after 1997:

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At 7:21 PM, Blogger wallisorama said...

You report that there are 4 million registered motorcycles in the U.S. and that 5-6000 will die in a crash each year. Does that factor, at all, the relatively small amount of people who frequently ride their bikes? Do you have a guess as to how many "registered motorcycles" belong to folks to don't ride often versus those who do?

At 1:15 PM, Anonymous Anonymous said...

Actually, I do not have any information on frequency of riding bikes that people own. I am sure it would vary with climate, northerners less so, southerners more so.


At 1:26 PM, Blogger Chad said...

This comment has been removed by the author.

At 1:28 PM, Blogger Chad said...

According to Sarah (somewhat of an expert given both family and professional history), less motor cycle helmets would potentially lead to less organ donation, not more. The amount of helmeted motor cyclists that led to organ donations in her Trauma ICU in KC far outweighed the unhelmeted. No helmet = quicker death in many cases and organ donation requires a fairly stable environment and extensive amount of time (for transplant team to be in place and family to make decisions) between brain trauma and organ harvesting. Personally, while her dad's helmet didn’t save his life, it kept the brain injury from being so catastrophic that he died before paramedics arrived. It kept him alive long enough for paramedics get him to the hospital and create a situation where organ donation was a viable option. Also, the amount of motorcycle accidents that result in organ donation is much lower than one might expect because of the pounding the organs take in these sorts of traumas - most motorcycle accidents produce unusable organs. Now, if we all stopped wearing helmets when we're shot in the head, we'd have a TON of donatable organs.


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