Home > Uncategorized > Relative injury risk of cycling, walking, driving and motorcycling

Relative injury risk of cycling, walking, driving and motorcycling

April 15th, 2011

Monday’s post on whether helmets encourage risky behaviour sparked a rather spirited discussion in the comments section. One of the louder claims was that, by choosing to write an article about bike helmets, I was making an implicit and unwarranted assumption that biking is more dangerous than, say, walking.

It’s an interesting question: is cycling more any more dangerous than walking? I went to look for some data. This is the first paper I found on Pubmed. I don’t know if it’s representative; I didn’t do a comprehensive search, and I’m under no illusion that this data will change anyone’s mind. Nonetheless, it’s data, from a paper published last fall in BMC Public Health. Researchers examined records from New Zealand’s Mortality Collection and National Household Travel Surveys to determine the incidence of injuries for several different survey periods. Here’s what they found for the most recent period, 2003-7 (the full paper is freely available at the link above, if you want to see the rest of the data):

Activity / Total injuries per year / Injuries per million hours spent travelling

Cyclists / 682 / 30.74

Car/van driver / 1714 / 2.10

Car/van passenger / 1086 / 2.89

Motorcyclist / 784 / 107.64

Pedestrian / 471 / 2.38

[UPDATE April 19: I've closed comments on this post, as I think we've reached a point of diminishing returns. Thanks to everyone for their contributions!]

  1. John Lofranco
    April 15th, 2011 at 13:23 | #1

    Wow. I would never have thought this would be such a controversial issue.

  2. .
    April 15th, 2011 at 16:38 | #2

    should my injuries while practicing stunts really count as indicating bicycling is more dangerous?

    I think that frequent injuries in sports often indicate it’s less fatal – frequent, but not debilitating crashes remind people to put on their safety gear and watch out.

    while some motorists end up thinking they could put on makeup while driving, or shaving.

  3. AG
    April 15th, 2011 at 19:30 | #3

    so roughly 30% of cycling injuries in non-motor-vehicle collisions involve “open wounds to head, neck, face or traumatic brain injury” which could arguably be prevented with a helmet. What would be interesting is to explore further the numbers that show traumatic brain injuries declined while other injuries increased (broken bones, etc.) Does that prove people are taking more risks with helmets and not hurting their heads/brains but hurting other body parts in the process? Very cool stuff.

  4. Brad
    April 16th, 2011 at 16:59 | #4

    did you consider the report on Ontario head injuries I linked from the previous discussion?

    http://secure.cihi.ca/cihiweb/en/downloads/bl_otr_mar2004_1_e.pdf

    out of 4,066 head injuries, only 54 were attributed to cyclists and for hospitalizations for serious head injuries only 50 were attributed to cyclists.

    Perhaps there is a difference between New Zealand and Ontario, or maybe there is a difference between serious and other injuries that are not serious, or then again, maybe there is a difference between the quality of the two studies.

  5. Brad
    April 16th, 2011 at 17:27 | #5

    another informative page with links to external sites that examines the relative risk of cycling

    http://www.cyclehelmets.org/1026.html

  6. Brad Kilburn
    April 16th, 2011 at 23:46 | #6

    a couple of more references.

    This one shows the fatality trend in Canada with a comparative graph of both cyclists and pedestrians

    http://www.vehicularcyclist.com/fatals.html

    and on another page, a graph from New Zealand showing cycling head injury percentage against helmet usage and head injury percentage in the general population:

    http://www.chapmancentral.co.uk/wiki/Cycle_helmets_overview

  7. Brad Kilburn
    April 17th, 2011 at 01:55 | #7

    also worth considering is Cycling England’s report, “Cycling and health. What the evidence?”

    http://www.dft.gov.uk/cyclingengland/site/wp-content/uploads/2009/01/cycling_and_health_full_report.pdf

    In the “risks of cycling” section it is written,

    “… while cyclists do bear a risk higher than car drivers per billion kilometers travelled, they bear a lower risk than pedestrians… It is also important to note that actual risk remains small… the level of risks also needs to be related to potential benefits in terms of improved health”

  8. Brad Kilburn
    April 17th, 2011 at 15:25 | #8

    and yet another report from the Australian government that dispenses with the notion that cycling is dangerous.

    from “Getting Australia Moving”

    http://www.cyclingpromotion.com.au/images/stories/downloads/CPF_Hlth_Rprt_08_web.pdf

    “The perception of risk from cycle accidents is often disproportionate to the actual risk. However, perceptions of risk were found to decrease with cycling experience. Whilst acknowledging the legitimate concerns people have to bicycle riding, the evidence demonstrates that in Australia, per 100,000 participants, an individual is seven times more likely to be hospitalised playing football than riding a bicycle. Risk-benefit analyses consistently report that the health benefits of cycling outweigh the risks by factors ranging from five to one, to 20 to one.”

  9. Brad Kilburn
    April 18th, 2011 at 13:01 | #9

    Hmmm…. No response to contradictory information

    Is there anything to conclude from this, or is the evidence presented good enough to show that the welfare of a person who cycles improved, rather than worsened as a result of riding a bicycle?

  10. AG
    April 18th, 2011 at 15:20 | #10

    @ Brad, interesting articles you posted, but instead of replying with more articles, how about criticizing the one Alex referenced? Is there something inherently wrong with the design of the study? Is there something wrong with the conclusion compared to the studies you referenced? I think conducting an argument by citing articles without first discussing the merits (or problems) of each is silly.

  11. Brad Kilburn
    April 18th, 2011 at 16:07 | #11

    I’m just a regular guy that reads the papers and tries to use a bit of common sense. By no means am I an analyst with a background in the apicable applied sciences involved.

    It seems to me that one need look at an entire issue in order to get a good idea of it’s scope and the concept of cycling being dangerous just doesn’t sit right. I’m sure cycling results in a few bumps and scrapes for those who try to push themselves beyond their limits, but overall, for most people cycling is as safe as anything anyone can participate in and provides additional benefits beyond it’s safety.

    Articles that portray cycling s dangerous are misleading and harmful to the public at large as they discourage peppe from cycling and distract from those that are more responsible for greater danger

  12. AG
    April 18th, 2011 at 16:21 | #12

    I’m a regular guy too…well…I’m a natural skeptic with a scientific upbringing and a technical career. I’m not advocating for/against helmets or for/against cycling as being portrayed as more/less dangerous. I just think the issue is clouded with all these myopic studies sometimes.

  13. Brad Kilburn
    April 18th, 2011 at 16:39 | #13

    I think it’s funny what studies get more attention. It probably says more about human nature than about the studies.

    I’m not sure just what is the cause of the specific findings of Alex’s presented study but what I can deduce by looking at other studies is that Alex’s study isn’t consistent with them.

    I think there are other issues at play here and I don’t think those issues are representative of reality

  14. Ian
    April 18th, 2011 at 19:52 | #14

    Brad,

    You say:
    “…what I can deduce by looking at other studies is that Alex’s study isn’t consistent with them.”

    One can just as legitimately say:
    “…what I can deduce by looking at Alex’s studies is that Brad’s studies are not consistent with them.”

    Both are equally valid statements but each imply certain conclusions as to which theories one believes to be the ultimate truth.

    If you’d truly understood this and the previous post/discussion, you’d know that Alex is not saying definitively one way or another whether cycling is inherently dangerous or that wearing helmets is intrinsically safer. He in fact explicitly says there is conflicting evidence and so the question is not settled one way or another.

    However you seem to have already made up your mind and pretty well every comment you are posting seems singularly focused on saying that any study or information that doesn’t agree with your beliefs is obviously flawed, mistaken or outright faked by people who have existing biases contrary to your own.

    Your position may be right. But it also may be wrong. And that is the point that Alex has been repeatedly trying to make. The science is not settled and that is why it is a topic worthy of further research.

    Blindly plugging your ears and repeatedly saying “you are wrong because this study says otherwise” is not indicative of an open mind when there exists significant evidence to the contrary.

  15. Brad Kilburn
    April 18th, 2011 at 20:21 | #15

    I don’t think I’m doing anything of the kind.

    I think I’ve simply provided a number of sources that run counter to the single study that heads the blog

    I do find it odd that something that is so beneficial as transportation by bicycle can be seen as extra-ordinarily dangerous. The inherent nature of a bicycle is one of improvement of health, not one of destruction of health, but I understand that to some people, the bicycle “seems” dangerous, even if it has a record that is as “safe” or safer than any other activity.

  16. Phil
    April 18th, 2011 at 21:36 | #16

    Brad Kilburn :
    I understand that to some people, the bicycle “seems” dangerous, even if it has a record that is as “safe” or safer than any other activity.

    The Major Head and Spinal Cord Injury Hospitalizations in Ontario,
    2001-2002
    bulletin that you cited in post #4 above states on page 10 that:

    Among head injuries the leading sports and recreation activity was
    driving a pedal cycle (23%, n=50). Other leading sports and recreation activities among head injuries
    included ATVs (15%, n=33), snowmobiling (9%, n=20), playing (running, jumping, skipping, general
    play) (8%, n=18), and dirt biking/minibike/motocross (6%, n=13).

  17. Brad Kilburn
    April 18th, 2011 at 21:40 | #17

    Yes, but the qualifier was, “sports and recreational activities”

    Overall, people on bikes make up a tiny percentage of serious head in jury victims

  18. Phil
    April 18th, 2011 at 22:05 | #18

    Brad Kilburn :
    Yes, but the qualifier was, “sports and recreational activities”

    In that case how would you rephrase your statement in post #15?

    even if it has a record that is as “safe” or safer than any other activity.

    Is it also possible that this statement requires qualification to be meaningful?

    Overall, people on bikes make up a tiny percentage of serious head in jury victims

    e.g. the number that were wearing helmets, the total time/distance/participants in each of the other activities

  19. Brad Kilburn
    April 18th, 2011 at 22:28 | #19

    Well, off the top of my head I guess I could rephrase by saying the risk of head injury per exposure hour hasn’t been shown to be greater for those on bicycles than for those off bicycles.

    I would suppose that that qualification would apply to your second query as well

  20. Brad Kilburn
    April 18th, 2011 at 22:56 | #20

    I’d also add that, “Injury” is a very broad and general category.

    Just what type of injury is a concern? Could a scraped chin be as much of a concern as a fractured skull? Is it fair to rate every type of injury equally?

  21. Phil
    April 18th, 2011 at 23:08 | #21

    Brad Kilburn :
    I could rephrase by saying the risk of head injury per exposure hour hasn’t been shown to be greater for those on bicycles than for those off bicycles.

    I’m unfamiliar with the literature. Can you cite the studies that show the contrary? i.e. the risk of head injury per exposure hour is less for those on bicycles (without helmets) than for those off bicycles.

  22. Brad Kilburn
    April 18th, 2011 at 23:21 | #22

    I have already provided links to information showing fatalities per exposure hours for various activities but I fear that may not satisy all. Clearly some have preconceptions that they don’t like to be challenged.

    Let’s just say that for all that people worry about injuries and accidents, what gets us all in the end are more often conditions that could be improved by riding bicycles on a regular basis. Just 4% of deaths are attributal to accidents and most of those deaths happen to people in automobiles.

    Cyclist on average live longer than do the general population despite the worries and concern some have about how “dangerous” it is to ride a bike

  23. Graeme
    April 18th, 2011 at 23:34 | #23

    Phil: Brad’s argument is nicely summed up here: http://www.youtube.com/watch?v=teMlv3ripSM

  24. Ian
    April 19th, 2011 at 00:46 | #24

    @Brad Kilburn
    “I don’t think I’m doing anything of the kind.”

    I understand that’s what you think. I simply said that is not what it appears to others.

    “I think I’ve simply provided a number of sources that run counter to the single study that heads the blog”

    No one is denying there are sources that run counter. If you’ll recall from the previous thread, there are more than one source that runs counter to your sources.

    That’s the point – there are legitimate studies that are apparently in contradiction to each other and that suggests no one can make a definitive conclusion one way or another. Yet you seem dead-set sure in your determinations being correct.

    “I do find it odd that something that is so beneficial as transportation by bicycle can be seen as extra-ordinarily dangerous.”

    Your characterization of this activity as being seen to be “extraordinarily dangerous” is further indicative of your own absolutism. Few, if any, of the studies referenced make any suggestion about cycling being “extraordinarily dangerous”. Some, which you assert are incorrect, are simply suggesting it is more dangerous than other things.

    But that certainly doesn’t make it “extraordinarily dangerous”. Walking down Yonge St may be statistically more dangerous than walking into a suburban cul-de-sac, but that does not automatically mean you are taking a huge risk with your life by being a pedestrian on Yonge St.

    I’m in total agreement that biking is a good thing and that society would be better off as a whole if more people did it. But it is not an activity that can be pigeon-holed when it comes to evaluating its risk and inherent dangers.

    For example, is the injury rate per km traveled for a professional bike courier in downtown Toronto more or less than an eight year old doing a leisurely bike ride with their family on a park bike path?

    The courier is probably way more skilled than the eight year old, but is biking in an environment significantly more hostile to cyclists and likely is pushing the limits of the traffic rules and his physical exertions.

    The eight year old is probably a lot less stable on the bike and not as seasoned to be able to anticipate hazards and respond to them when they occur. But then they are facing a lot fewer threats and are going at a much slower velocity. She’s not going to be dealing with a collision with a car but rather falling over sideways as her biggest risk – a fall that due to the dynamics of her position on the bike has a significant chance to cause her head to smack the ground. With a helmet this would just be a scary bang but without one, likely to cause serious damage.

    So can one really lump those two cyclists into the same statistical pool when evaluating whether cycling as an activity is more or less dangerous than walking down the sidewalk, driving down the street, swimming, pogo-sticking or just sitting on one’s butt watching TV?

  25. Phil
    April 19th, 2011 at 00:48 | #25

    @Graeme
    Thanks for the link Graeme, I haven’t seen that sketch in a long time. My guess was that you had posted something like this: http://blog.lextext.com/_photos/DSCN0126.JPG

  26. Graeme
    April 19th, 2011 at 01:09 | #26

    @Phil
    Ha! That just about sums it up.

    Brad: “Try as they might helmet proponents cannot claim cyclists receive head injuries to any greater degree than others.”

    Alex: Injuries per million hours spent travelling: Cyclists 30.74, car drivers 2.10, pedestrians 2.38

    Brad: “The risk of head injury per exposure hour hasn’t been shown to be greater for those on bicycles than for those off bicycles.”

    John Cleese: “Sorry, time’s up.”

  27. Brad Kilburn
    April 19th, 2011 at 01:34 | #27

    I’d say my argument could be better summed up by saying, it’s not that something can happen but more about how likely something is to happen.

    I think by looking at what has been presented on this blog, the majority findings are that cycling is safe. Not all would agree, but that ‘s not unexpected. Views on or about cycling usually represent a cultural bias; asking a Texan or a Copenhager would yield wildly different opinions.

  28. Brad Kilburn
    April 19th, 2011 at 03:35 | #28

    Ian – I guess when the government of England examines all the evidence and issues the report I linked, I would lean toward it’s conclusions. It’s not that cycling is without danger, nothing is, it’s just that, on balance, the preponderance of evidence reveals that risking a bicycle is not any more dangerous than walking

  29. Graeme
    April 19th, 2011 at 04:53 | #29

    “I guess when the government of England examines all the evidence and issues the report I linked, I would lean toward it’s conclusions.”

    Oh, good. Here’s another report from the same department (Transport) of the UK government: http://www.dft.gov.uk/rmd/project.asp?intProjectID=10083

    From its conclusions:
    “The critical review of the extensive literature concludes that there is a considerable amount of scientific evidence that bicycle helmets are effective at reducing the incidence and severity of head, brain and upper facial injury.”

    “After consideration of the range of opinion pieces concerning bicycle helmets the authors conclude that ‘The way in which the debate has been conducted is unhelpful to those wishing to make a balanced judgement on the issue.’”

    I couldn’t have put it better myself. Of course, I understand that you’ll consider THIS report from the UK Department of Transport to be meaningless and biased, while THAT report from the UK Department of Transport is definitive and can’t be questioned.

    Or perhaps we should conclude from these conflicting reports that there are differing views on this complex issue, and the fanatical myopia you’ve exhibited in these threads is precisely what sabotages any attempts to discuss the issue rationally.

  30. Brad Kilburn
    April 19th, 2011 at 06:07 | #30

    And just where in that report does it mention cycling holds a greater danger than being a pedestrian?

  31. Phil
    April 19th, 2011 at 07:31 | #31

    Miss Louise: Welcome to 2nd grade children. Now class, can any of you tell me some of the differences between walking and riding your bike?
    Sid: I walk pretty slow but I can ride my bike really fast!
    Johnny: When I’m walking I stay on the sidewalk but sometimes I ride my bike on the street and the bike trail.
    Mary: It only takes me one step to stop walking but I have to go a long way to stop my bike.
    Pete: My sneakers never go flat all of a sudden like my bike tire does sometimes.
    Jane: One time my bike broke and I fell over.
    Mitch: I can stand still without falling over but I can’t keep my bike up unless it’s moving.
    Miss Louise: very good class, now go on the web and tell Brad what you just told me.

  1. No trackbacks yet.
Comments are closed.