GHSA's sensational report

Taking an incredibly liberal definition of the meaning of "news", much of the main street media was reporting on a report released by the Governors Highway Safety Association report that included the fact that cyclist deaths are up 16% over the last two years. This, of course, has been known since the NHTSA reported the 2012 fatalities nearly a year ago (some of the data has been updated since then causing a change of 4 fatalities).

There are a few facts that are being widely reported, and a lot of the context is being left out.

The number of bicyclists killed in motor vehicle crashes between 2010 and 2012 was up 16 percent 

That's true. But 2010 had the fewest number of bike fatalities on record. So the first thing to note is that there is some reversion to the mean. 2011 was basically on the trendline, and while 2012 is above it, so were the years 2004-2008. 

This two year increase is similar to ones seen from 2003-2005, 1992-93 or 1984-86. When you have an outlier, like 2010 was, it's not unusual to see a short term rise. Unscrupulous people can use that to hide the longer trend as did global warming denialists who liked to claim for many years that, because 1998 was such a warm year, "there has been no recorded global warming for more than a decade," but then 2010 came along and ruined that.  Similarly in each of the earlier cases where deaths went up, the number of deaths eventually reverted to the overall trend down. That doesn't mean this will happen again, with more people biking, it's possible we will continue to get more crashes and more deaths, but it isn't yet reason to panic. 

Three years isn't much of a trend. 

Furthermore, over the same period, injuries were down from an estimated 52,000 to 49,000, a fact which should conteract some of the worry. 

I'd be willing to bet even money with anyone that the number of bike fatalities in the US will be lower in 2013 than they were in 2012. 

Lack of helmet use is a major contributing factor in fatalities. 

This paper is very pro-helmet.

The lack of universal helmet use laws for bicyclists is a serious impediment to reducing deaths and injuries, resulting from both collisions with motor vehicles and in falls from bicycles not involving motor vehicles.

But some of the sources it cites are dubious. For example, Haworth isn't a study, but a report that looks at many other studies including several [Thompson, Rivera, etc...] that have been discredited. 

In the paper, Dr. Williams notes that 65% of cyclists were reported to not be wearing a helmet (with another 18% unknown) and that 46% of cyclists reported that they never wore a helmet. Certainly the other 54% only sometimes wear a helmet, which means that the rate of actual helmet wearing isn't too far from 65%. The 65% comes from FARS data, which while significantly better than before 2010, still has some flaws (The form gives those filling it out a choice between several safety features like helmets, lights, etc...And though it instructs them to choose "all that apply" in reality they only choose one.) In addition those that are killed are biased towards those who take bigger risks. So while there is likely a correlation between not wearing a helmet and dying in a bike crash, some of it probably comes from taking higher risks and not wearing a helmet. 

Which is not to say that helmets don't save lives or reduce injuries. They likely do. But I suspect the lack of universal helmet use is a minor contributing factor to bike fatalities. [I'm working on a post about helmet use coming from my review of FARS data and I don't want to put in any spoilers here, but I have more to say on this]. And it is another jump from saying that helmets save lives to saying that universal helmet use laws save lives, for which the evidence gets even more contentious. 

Despite the association of biking with healthy lifestyles and environmental benefits, a
surprisingly large number of fatally injured bicyclists have blood alcohol concentrations of
0.08% or higher.

It's higher than it should be, but not surprising unless you think that all cycling is for recreation. It's 28%*, which is lower than the percentage of driver fatalities (31%) and pedestrian fatalities (36%). I'm not sure why anyone would expect cyclists to be significantly better behaved. If anything, the fact that many repeat DWI offenders lose their licenses would cause me to expect cyclists to have more alcohol related fatalities. My analysis of DC area bike crashes shows that cyclists killed in traffic crashes are slightly more likely to be killed by a driver who was under the influence than to be under the influence themselves.

Drunk biking is a bad idea, and we should do more to educate cyclists about it, so this study is good in that regard. But there's nothing unique about their bad behavior. 

The media has done a less than stellar job of reporting this, focusing on the more sensational details mentioned above - none of which is "news" but rather regurgitated stats from NHTSA and IIHS. 

Martin Di Caro nails it on the fatality rate, which Dr. Williams sort of breezes over, as a critical fact in all of this. Di Caro quotes an advocate from the Alliance for Biking and Walking.

“As the rate of bicycling increases, the rate of fatalities actually decreases,” said Jeffrey Miller, the advocacy group’s director. “As more people are bicycling the overall number of crashes does not keep pace and actually decline in many cities.”

But then he misses it here.

Among the factors the GHSA blames for the increase in deaths (from 621 in 2010 to 722 in 2012) are alcohol and helmet use. 

Actually the paper never blames those for the increase, as helmet use and BAC levels in cyclists remain pretty constant over the time period. The only cause for the increase the paper brings up is increased exposure. 

And another misleading statement come from Kara Macek, a GHSA spokeswoman.

“We have to look at the numbers. We have to look at where the problem exists. And it exists in urban areas such as D.C.”

That's not what the report says. It says that urban areas have become a larger percentage (69% up from 50% in 1975) of total fatalities. But the total fatalities in urban areas have gone down in the time, even as the population has gone up (and so has cyclist exposure). 

NPR has a bad line too.

 And a lot of those bikers are male, drunk and not wearing a helmet.

No. A lot of them are male, and a lot of them are not wearing a helmet, but only ~30% are drunk. Fewer than that are all three. 

Anyway, the whole thing might result in a good conversation, and many of Dr. Williams recommendations like education, better enforcement, separated bike facilities, slowing down cars and getting fewer road users to get on the road after drinking (and yes, encouraging cyclists to wear helmets) are things cyclists can support, but there's nothing really new about it and a lot of the statistics are presented out of context. 

* Williams makes a reporting error here. He says that it's 28% for cyclists 16 and over, but the IIHS says that's for cyclists 20 and over. This is also how FARS reports the data, so it's likely that is what is meant. It's also an estimate done by imputation. "Imputations for missing BACs were provided by the U.S. Department of Transportation's multiple imputation model beginning in 1982." Actual data actually shows a lower rate. For all cyclists 16 and over, only 16.2% have a BAC of 0.08 or higher. For those who are tested, 27% are that high. But there are many where no test is given, it's not reported, it is positive but too low to be measured or blank. I'm not sure how that imputation model works.

Comments

[Mike]

If you bike drunk you're more likely to die. If you drive drunk you're more likely to kill. On balance, if someone is going to either drive or bike while drunk, I'm gonna have to say it's better for society for them to bike.

[SJE]

What is the rate of fatalities associated with drunk biking versus drunk driving? How does it compare to driving fatality rates 40 years ago, before legal and social changes discouraged DUI.

[ACyclistInThePortCity]

On the bright side, Dr Gridlock nailed it, mentioning only the ridership increase in the lede.

[washcycle]

SJE, I don't know what you mean by "the rate of fatalities associated with drunk biking". What are the numerator and denominator you're looking for?

[Smedley Burkhart]

Apologies for not having read the source material, but is there any speculation on the cause of the overall downward trend in fatalities? Presumably non-fatal accidents are steady or increasing.

[washcycle]

I think there are several theories out there.

1. Drunk driving is down
2. Fewer kids are biking (probably the main one)
3. Design of better facilities for cyclists
4. Bike lights are much cheaper and better.
5. Increased helmet use (at least since 1975)

Non fatal injuries have dropped from an estimated 75,000 in 1988 to a low of 41000 in 2004 and back up to an average of 50,000 over the years 2007-2012.

[Crickey7]

Indeed, probably no single cause.

[SJE]

Sorry Washcycle. It is 28% for cycling, which is lower than drivers. I wonder how many automotive deaths were linked to drinking 40 years ago.

[John Laidlaw]

I've been a "driver" for sixty years - six of them exclusively on a bike, the rest in cars and trucks, as well as the bike.

One factor that is sadly lacking in the study is any indication of the experience of the cyclist.
I can recall, as a young rider, being very concerned about the possibility of a fall, and hitting my head. The first ten years of cycling taught me that this was, really, very low - at least as long as I did not take unnecessary risks.
A helmet will reduce/eliminate the severity of a concussion - it will NOT "save lives", and any argument based on that is a false one.
The other comment is on "risk". What passes for "risky" behavior in a less experienced rider may well be merely calculated action. As I've grown in experience, I've discovered that what I had thought dangerous was not quite so - if I approached it correctly, knew when it would or would not be dangerous, and so forth - so what the inexperienced, or the non-cyclist may see as "risky" proves to be as reasonably safe as many things that same person would do in a car.
Experience can be a big factor in a rider's safety.

[washcycle]

My personal reading on helmets goes something like this:

They don't really do anything for concussions. For slow speed crashes they can help to mitigate a head strike and are particularly good at preventing skull fractures. Because kids are more often in slow speed crashes they're particularly good for them. When being hit by a car they probably save some lives, but not as many as boosters seem to indicate. Often a victim has more than just a head injury.

[Crickey7]

Let's keep those numbers trending down!

[Smedley Burkhart]

As I see it, the list of mitigating factors above, would act on the accident or injury rate, not fatalities, per se, and I suspect it has more to do with the increasing use of aggressive interventions for severe head injury, e.g. intracranial pressure monitoring.

Also, re: helmets, I don't think there is evidence that they mitigate concussion significantly, but, as washcycle writes, prevent skull fractures. Skull fractures are obviously not a good thing in and of themselves, but they are associated with epidural hemorrhage, due to tearing of arteries in the damaged tissues. These are high-pressure bleeds, which kill rapidly after the famous "lucid interval". Sorry for the technical banter.

[DE]

Helmets can do some good in some situations, but they are not a panacea and I think they serve as a red herring when discussing cyclist safety, diverting attention from more important issues.

Since they can actually cause or worsen injuries in some limited cases--added torsional forces and the ability to catch on things that otherwise would not be caught--I'd be upset if they were mandated. It would cause me to break the law, in fact. As in most things, I support freedom of choice for things that don't harm others.

I wear mine when mountain biking and in the winter or rainy conditions. I have wrecked countless times over 20+ years of mountain biking and have never once hit my head. This is, of course, anecdotal.

On the other hand, I could also cite my girlfriend, who wrecked and hit her head while wearing a helmet road biking and received a concussion and months of headaches. She thinks the helmet maybe saved her, but she doesn't remember a single thing about the accident or the half hour that followed, so who knows.

[washcycle]

Smedley, I think if there are fewer accidents (or crashes for the purists out there) then there are probably fewer injuries and fatalities.

[Smedley Burkhart]

Right. I should have said, "assuming the crash rate has been constant," which I thought was the case.