Home > Complete Streets, Safety Issues, Visual Stimulus > Graphic Friday: Safety In Numbers, Change Through Numbers

Graphic Friday: Safety In Numbers, Change Through Numbers

Graphic Friday

(click for larger view (PDF))

Contrary to some of the fears I’ve seen expressed (PlanforTC comments), as the numbers of people on bicycles increases, the trend is that crash rates decline, not increase. The latest data crunching to support this is out of Minneapolis.

This happens, in part, through the increased visibility of cyclists and people on foot when active living becomes more common. Which, in turn, also increases the numbers as nothing is better for changing behaviors than…more people changing their behavior.

Despite our rugged individualism, we remain human and humans are innately social animals who strive to be perceived normal. Driving a 2-ton motorized transportation pod to buy a gallon of milk is only normal because people do it, not because it makes sense.




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  1. Rick Shimel
    February 11, 2011 at 12:37 pm

    Gary, no sale on the police statistics graph. This is a police report, not a scientific study. Bicycle/car crashes are at best under-reported, if reported at all. There is also nothing in this graph that would indicate behaviors have changed. You’re making stuff up.

  2. February 11, 2011 at 1:07 pm

    Non-fatal or injurious car-bicycle crashes are likely under reported, yes. Crashes involving “ugly” & “costly” results-are likely to be reported, particularly in one of our most bikable cities.

    Anyway, I didn’t make the report; just passing it on & adding commentary. If it doesn’t represent a pattern of success for you, perhaps one of the following reports/studies will. I will gladly publish your analysis of these 4, including the one above, if you choose to write it. I haven’t read through them, but they are frequently cited.

    Other Safety in Numbers Studies:

    • Out of Australia: http://bit.ly/fEablN (PDF)
    • Out of New York City: http://bit.ly/dT2KMc
    • 2003 Berekly Study: http://bit.ly/g74rcl (PDF)

    The behaviors that changed? Increased commuters by bicycle.

  3. Brian
    February 11, 2011 at 1:48 pm

    Huh. Well if one were going to do a scientific study on serious vehicle/bicycle interactions, police reports for a given population (City of Minneapolis) would be the good place to start. Also note, according to the article citied above, that the police reports include accidents for bicyclists that are not counted in the total number of bicyclists.

    “All but one of the fatalities and the preponderance of those injured last year were male, while close to half were between ages 10 and 24.”


    “The number of cyclists is taken from the number of people ages 16 or older ….”

    I also suspect that serious accidents are under-reported, but the study definitely under-counts the number of bicyclists.

  4. Mike Grant
    February 11, 2011 at 2:04 pm

    Of course it would be difficult based on this graphic alone to figure out the correlation versus causation question of the displayed increasing bike ridership and decreasing car/bike crash rate. But visibility of cyclists would seem like one plausible explanation. Another explanation might be because, possibly, Minneapolis may have constructed more bike-only facilities (i.e. separated lanes). In fact, from looking into possibly moving there last year, I think they have done quite a bit of that. Those facilities would, by design, be far less likely to lead to bike/car crashes.

    Under-reporting of crashes as Rick has suggested would seem fairly implausible to me. At least as far as suggesting that for some reason starting in 1998 and continuing to 2008 people just decided to stop calling the cops as often as before.

    Oh, don’t take my point to be that TC needs to build more separated facilities for bikes. Bikes on city streets help address a couple of challenges. One is it more people on bikes means fewer cars on the streets. The other is that, in great enough numbers, it forces drivers to slow down and be more cautious.

  5. February 11, 2011 at 3:02 pm

    The pattern supports the idea that policies & priorities aimed at getting people to make more commuter trips by foot or wheel can make those choices safer over-all. Certainly better infrastructure counts. This isn’t happening in a vacuum, there are many variables that come into play. To me, it’s a convincing pattern.

    Here are similar graphs from the NYC study linked in the previous comment & one from Portland. Of course, without the context of each study, they aren’t intended to answer the questions raised:

    And, Portland:

    By the way, nice set-up for a future post, Mike. Segregated bike lanes & paths are something I plan on writing about in a TC context.

  6. Rick Shimel
    February 11, 2011 at 3:32 pm

    Thanks for the challenge but you know I’m way too lazy to do any serious work. The behavioral changes I’m referring to are drivers becoming better operators because there are more bikes on the streets. This has been your position in the past and I don’t subscribe to it. Also, not graphed, I question who was responsible for the crashes the car or bike? I concede that more and more people are biking and I think that is a good thing. I also agree that only serious accidents with resulting injuries and insurance company involvement are reported. If this graph was re-titled to Estimated Number of Serious Car/bike Crashes I would find it more believable.

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