PeopleforBikes promotes a new study

There hasn’t been time yet for a thorough review of the new study of barrier-separated bikeways on streets now being touted by the bicycling-industry lobbying organization PeopleforBikes, though claims of lack of traffic conflicts on these bikeways fly in the face of the experience of actually riding in them, and the results of earlier studies. The saying on the sign below is pertinent. Update, July 1, 2014: a quick “review preview” is now available.

The amount of energy necessary to refute bs is an order of magnitude bigger than to produce it.

A comparison

As is usual among advocates for such  bikeways,  PeopleforBikes uses the feelgood propaganda term “protected bike lanes” for them — though they are technically paths, not lanes, and are unprotected where most car-bike crashes happen, at intersections and driveways. PeopleforBikes cites three earlier studies as setting the stage for the new one, and offers a tepid acknowledgement of criticism of these studies, with a link to criticism of only one of them, along with an appeal to groupthink, and while reiterating the studies’ conclusions:

Three widely noticed Canadian studies, led by Harvard’s Ann Lusk, the University of British Columbia’s Kay Teschke and Ryerson University’s Anne Harris, focused mostly on safety. And though all three concluded that protected bike lanes greatly improve bike safety (28 percent fewer injuries per mile compared to comparable streets with no bike infrastructure using Lusk’s methodology, 90 percent fewer using Teschke’s; in Harris’s study, protected lanes reduced intersection risk by about 75 percent), they’ve drawn some thoughtful criticism for underexamining the importance of intersections, where most bike-related conflicts arise.

The three Canadian studies which PeopleforBikes cites have been reviewed, in detail, and demolished.

The study Lusk, A. C., Furth, P. G., Morency, P., Miranda-Moreno, L. F., Willett, W. C., & Dennerlein, J. T. (2011). Risk of injury for bicycling on cycle tracks versus in the street. Injury prevention, 17(2), 131-135, claims a 28% lower crash rate for cycle tracks in Montreal, relative to comparison streets. Flaws of the study include describing stretches of paths in parks and away from streets as cycle tracks; including stretches which had not been built yet in the reported mileage; selecting a multi-lane comparison street 10 blocks away with heavy, faster traffic for comparison with a cycle track street which is small and has light, slow traffic, examining short stretches which end just short of busy intersections; giving the length of one of the paths as twice as long as it is, halving its reported crash rate, and neglecting injuries to pedestrians. A detailed rebuttal and a link to the study online may be found here. Another review reaches similar conclusions.

Teschke, K., Harris, M.A., Reynolds, C.C., Winters, M., Babul, S., Chipman, M., Cusimano, M.D., Brubacher, J.R., Hunte, G., Friedman, S.M., Monro, M., Shen, H., Vernich, L., & Cripton, P.A. (2012). Route infrastructure and the risk of injuries to bicyclists: a case-crossover ctudy. American journal of public health, 102(12), 2336-2343. has been reviewed and debunked by John Forester. The central problem is that the one facility described in the study as a cycle track and used for comparison with all the others is a bikeway on a long bridge separated by a Jersey barrier, with no cross traffic.

M Anne Harris, Conor C O Reynolds, Meghan Winters, Peter A Cripton, Hui Shen, Mary L Chipman, Michael D Cusimano, Shelina Babul, Jeffrey R Brubacher, Steven M Friedman, Garth Hunte, Melody Monro, Lee Vernich and Kay Teschke, Comparing the effects of infrastructure on bicycling injury at intersections and non-intersections using a case–crossover design, 19:5 303-310 doi:10.1136/injuryprev-2012-040561, has also been reviewed and demolished. The comments published on the Injury Prevention Web site are a condensed version of the ones published here and here. An explanation of how they came to be condensed is here. The authors oddly found bicycle-only paths in parks to be 17.6 times as dangerous as bicycle-only paths in (or adjacent to) streets. They find multi-use paths in parks to be 22.8 times as dangerous as bicycle-only paths in streets; and riding in the street to be 20 times as dangerous as riding in a bicycle-only path in the street. These results are bizarre and contradict those of numerous other studies.

Note that the authorship of these two studies overlaps.

Teschke gave a presentation at the 2012 Velo-City conference in Toronto. I have posted comments on this presentation. My review addresses the deficits in epidemiology as an approach to the study of traffic safety, and also, specifics of the presentation. The graphics for the presentation display the preposterous result from the Harris study that bicycle crashes were 2000% as high on streets without cycle tracks as on streets with them, although the study also reports that more than half of all the crashes did not involve a motor vehicle. There are other absurdities. Also, it is clear from the authors’ presentation at a conference that they do not understand the definition of a collision, or intentionally skewed their data by describing single-bike crashes as collisions.

The authors of these studies flaunt their academic credentials, which may look impressive except when noting their errors of methodology and selection of data. These are not unbiased researchers: they are avid promoters of separate bikeways on streets, and the bias shows.

19 Responses to PeopleforBikes promotes a new study

  1. I never read JF’s review of the case-crossover design. Has anyone else verified that there was only one cycletrack during data collection? That’s ridiculous.

    • This is from page 3 of Forester’s paper:

      “Today, the Vancouver city website shows that cycle tracks exist on the Burrard Bridge, Hornby Street, and Dunsmuit Street. But the Hornby and Dunsmuir cycle tracks were installed in or after 2010. The Toronto Staff Report, Bikeway Network, 2011, says that their first cycle track is planned for installation in 2011 along the Bloor Viaduct.

      “In summary, the only cycle track existing in the study cities during the study dates was on Vancouver’s Burrard Bridge. This bridge is at a high level to allow ship passage, with long approaches at each end. Being a bridge it has no crossing or turning traffic to produce the conflicting traffic movements that make cycle tracks so dangerous.”

  2. Roberta Franchuk

    Some of the links in this article are broken, but John Forester’s critique can be found at http://www.johnforester.com/Articles/Facilities/Infrastructure%20&%20Injuries.pdf; on page 3 of that PDF he states “The crashes in this study occurred in some months of the years 2008 and 2009. The crashes all occurred within the cities of Vancouver or Toronto. Today, the Vancouver city website shows that cycle tracks exist on the Burrard Bridge, Hornby Street, and Dunsmuit Street. But the Hornby and Dunsmuir cycle tracks were installed in or after 2010. The Toronto Staff Report, Bike- way Network, 2011, says that their first cycle track is planned for installation in 2011 along the Bloor Viaduct.”
    First, the Teschke report says “The study population consisted of adults (≥ 19 years) who were injured during bicycle riding and treated within 24 hours in the emergency departments of the following hospitals between May 18, 2008 and November 30, 2009.” So that’s the data collection time confirmed.
    And indeed, the City of Vancouver website includes a PDF of traffic counts in the ‘separated bike lanes’ (http://vancouver.ca/streets-transportation/separated-bicycle-lanes.aspx) that shows counts in the Burrard bridge beginning August 2009, at Dunsmuir street in July 2010, the Dunsmuir viaduct in March 2010, and Hornby St. in July 2011. The Toronto Staff report he sites is at http://www.toronto.ca/legdocs/mmis/2011/pw/bgrd/backgroundfile-38906.pdf and says exactly what Forester quotes. So yes, apparently they did use data from only one cycletrack (the Burrard Bridge).

  3. From P4Bs: ‘”This has never been done on this scale — having five cities and a number of different sites being done at the same time,” NITC spokesman Justin Carinci said in an interview Monday. “The number of hours of video review is unprecedented. But the perceptions piece is really the most definitive of it: This is a big enough sample that we could say for each of the (projects), people feel safe riding them. People say we should have more of them.”‘

    That is right. It is very little except 2 things: (1) a survey of people who think protected lanes feel safer (we already knew that a lot of people think that, despite the reasons to think otherwise); (2) 168 hours of video on some intersections showing a few minor conflicts with motorists and cyclists on the ‘protected lanes.’ P4Bs wants that tiny sample to demonstrate how safe the lanes are, but the study didn’t compare the number or types of conflicts both before and after the PBLs were installed.

  4. One thing I find odd is that 168 hours are exactly one week of 24-hour days — and I also read on bikePortland, here, that 144 hours — exactly 6 days — were selected for review from the 168 hours of video. What explains this? Also, when I rode the Montreal bikeways, potentially crash-causing conflicts — including a couple of near-misses — occurred more like one every 5 or 10 minutes, on 9th Avenue in NYC, there were illegal left turns across the bikeway, and on Pennsylvania Avenue in DC, there are illegal U-turns. I’m going to post an edited version of my Rue Rachel video to highlight what I’m discussing here.

  5. To an outsider, this all sounds a bit like a study of the benefits of anesthesia for surgery or of the advantages of electric lighting over kerosene. Don’t several decades of experience in Northern Europe demonstrate the usefulness of dedicated bicycle infrastructure?

  6. The bike industry has no shame. Its wholesale embrace of junk science maims and kills its customers. John Allen, thank you for such a clear and concise documentation of why this “study” is so bad.

  7. I’d prefer “advocacy research” to junk science, in order to be a little more polite. The problem with advocacy research is that it often tends to want to prove something with statistics rather than test a hypothesis. So one has to be wary of methodologies.

    The case-crossover method applied to bike crashes by the above authors always gave me heartburn, but I’m not a mathematician and am glad one critiqued these. What I do know as a working scientist and a dozen-year member of my county’s transportation advisory board is one has to pick one’s samples carefully. Not all segments of road or path are equal, so how one picks control segments is critical. For example, we have a 4 mile length of bike lane we built in the last half dozen years along Diamond Drive, one of our two main arterials. 3.5 miles of it have curbcuts that are spaced far apart and all but a couple have good visibility. The last half mile has ten closely spaced and heavily used curbcuts. If you took the average of crashes over that four miles, it would be meaningless because IIRC, virtually ALL of the crashes and close calls are in….the last half mile. So if one were to compare the quarter mile of protected bike lane that exists on the Los Alamos Canyon Bridge (actually, a 7 foot wide sidewalk shared with peds) to the Diamond bike lane, you could run into trouble with crash comparisons if you randomly selected a location.

    All of John Allen’s other caveats about the US vs. Europe apply in asking whether ridership will jump to Copenhagen levels. Sure, high ridership exists in ideal locations such as Davis, CA. But one cannot compare a city like Albuquerque to one like Bremen, Germany or Amsterdam for all the reasons Allen mentions.

    I’m also a little concerned at the LAB’s recent wholesale endorsement of separate facilities, as given in the BRAIN interview (link after this paragraph). Sure, having even a mediocre separate facility may be better for your garden variety cyclist than having a badly designed high speed arterial but as we all know, the devils are in the details. I’d hate to cut the ribbon on a bad design that has cyclists smeared all over intersections just to give them safety between intersections. But after that, to use Preston Tyree’s well-worn phrase, “it depends”.
    http://www.bicycleretailer.com/north-america/2014/05/28/q-new-league-study-challenges-assumptions-about-fatal-bike-crashes#.U5hsO3eqoqM

    Let’s keep the discussion going here. Also, thanks, John, for the easy to read spam filter. A lot of times I can’t read those convoluted letters in the more typical ones that say “type what you see”.

    • I’d also add climate to the list of differences. West-coast cities in the temperate zones — European and American — benefit from the moderating effects of a prevailing wind off the ocean, and more moderate — though often wetter — weather than inland and east-coast cities. Northern winters and southern summers in the USA also are an impediment to bicycling. Electric bikes will make hot summers easier to tolerate.

      • I read a study that tried to account for the effect of climate on cycling mode share, and it found that it couldn’t account for the difference. Rather the study concluded that differences are more due to the costs of automobile ownership (as you point out above) and commuting distances.

        http://www.sciencedirect.com/science/article/pii/S0967070X05001381

        One of the authors is John Pucher, so maybe this is already in the category of “advocacy science”, but from my reading it sounded like a relatively well-done study.

    • Thanks for mentioning that LAB study. From comments posted elsewhere, it would seem that the LAB study (1) lumps all from behind collisions together but separates from the front collisions into various types (add up those from the front and it is roughly equal to from behind) which makes from behind collisions seem very high (2) overcounts from behind collisions by taking mid-block collisions (e.g., right hook by motorist turning into driveway) as from behind and undercounting intersection collisions by counting some as being too far back from the intersection despite the collisions being of the same nature as intersection collisions. I can’t confirm this, having only seen rough reports.
      This is the kind of thing we might expect as the league has aligned itself with pedestrian advocates and “bikeway” advocates, against the true interests of most of its members.

      • Hmm, all my friends who live in Florida say that they ride much less in the summer, not to speak of friends in Phoenix where it gets up to 110 (43 Celsius) — and I know that I ride less here in Boston in the winter. Of course, that’s anecdotal.

  8. Yes it’s bizarre, particularly the video from DC. The cars and bicycles converge on the same area at the same time, so I would hesitate to call it ‘separate infrastructure’ as it seems, on the contrary, very mush ‘shared’. I think it’s known that tracks on two-way streets should preferably be unidirectional and stick to the corresponding side of the street, but mostly there should’ve been a signal for both the drivers (right turn on green arrow only) and the riders in order to remove contention. After all, isn’t that what traffic lights are for?

    However, is it the result of the bike-lobby conspiracy or local incompetence?

    I’m sure you have seen materials like the following http://youtu.be/XuBdf9jYj7o which show that even given the climate, the terrain, and the city sizes, cycling had been in decline – until it was revived. Clearly a lot of thought (and possibly trial and error) has gone into the proper cycling facilities, but now that they are there for all to see, why not just copy them?

  9. How are you going to identify the “proper” cycling facilities and distinguish them from the improper ones? A lot of thought (and trial and error) went into the Berlin side paths, but the Berlin police study still found them to be far more dangerous than riding in the streets. As a result, Berlin began to move toward bicycle boulevards and painted stripe bike lanes in the streets–then found modal share shot up markedly.

  10. I look forward to the full review!

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