Forester Fudges Figures

November 10, 2013

On this article http://momentummag.com/features/the-rise-of-the-north-american-protected-bike-lane/page-5.html

is a comment containing this link

http://ntl.bts.gov/lib/25000/25400/25439/DOT-HS-803-315.pdf

to a study by Kenneth D. Cross and Gary Fisher which is cited by John Forester in Effective Cycling to support his claim that accidents where the cyclist is hit from behind are not a large risk, and thus we should not be afraid to ride with traffic and even somewhat in the part of the road where automobiles commonly travel. I believed this claim for decades, because presumably he would represent that study fairly, and not cherry pick or distort the data to support his position.

What can I say, I was young and naive, right?

Surprising to me, when you read the cited statistics, you discover that things are not exactly the way Forester claimed. Accidents in which cyclists are hit from the rear (Problem Type 13, p. 33) cause 23.4% of the fatalities. That’s not at all the impression you would get from reading Forester. It is true that 70% of these fatalities occur on narrow, rural roads at night, and alchohol is often involved, but that still leaves 7% of all fatalities in the non-narrow+rural+night case of hit from behind.

Is 7% large? Probably. Riding against traffic poses a significant risk of injury (p. 174, a factor in 20.1% of injuries) but only a 4.8% risk of a fatal injury.

In contrast, sidewalk riding in the presence of driveways (Problem Type 8, p. 31) is not nearly as dangerous as portrayed by Forester — no fatalities! (Yes, there are injuries, 5.3% of the total).

And thus my opinion of Effective Cycling takes another lurch downwards. The study itself is interesting; what I read there makes me feel happy about my decision to equip my bike (and all my kids’ bikes) with hub-powered lights that are always on when the bike is rolling; again and again, visibility is a factor.

One Response to “Forester Fudges Figures”

  1. Fred Says:

    No hyperbole, best blog post on cycling ever. I so loved this accurate and concise analysis.


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