Who’s Responsible?

There is a claim floating around that some study has concluded that motorists are responsible for some 90% of car-bike collisions.

This would be a lot higher than is generally appreciated. I’ve grappled with this a little bit before in Understanding Collision Summaries, where I pointed out an inexplicably high proportion of  “other” violations assigned to bicyclists.

So far, I’ve found a page at projectfreeride.org with a table that is said to be source from Tomlinson, David. Conflicts Between Cyclists and Motorists in Toronto, Canada. Link to a .pdf on the Velomondial.net.

The same claim can be found in a newslettery article dated Aug 19, 2009 on a University of Toronto website entitled Smart Cycling. the information was supplied by a physcian, Dr. Chris Cavacuti, who is also involved with projectfreeride. And a correction with that article that was posted Aug 26:

In the interview, Dr. Cavacuiti is quoted as saying “The [Toronto Collision] study concluded that cyclists are the cause of less than 10 per cent of bike-car accidents”. Dr. Cavacuiti has asked us to make readers aware that the Toronto Collision study was actually designed to look at the cause of bicycle/motorist collisions but not culpability.

It is actually several studies conducted by the Charles Komanoff and member of the Right of Way organization in New York that concluded that concluded that cyclists were strictly culpable for less than 10 per cent of bike-car accidents.

Dr. Cavacuiti would like to apologize for any confusion this error may have caused.

On the projectfreeride page,  in a statement summarizing Tomlinson’s findings, the page at projectfreeride says “In fact, cyclists are the cause of less than 10% of bike-car accidents in this study”. Is that really what Tomlinson found? Or should the correction mentioned above be also applied to the projectfreeride page too?

This claim got picked up by the Freakonomics blog, garnering wide exposure.

Skepticism at the commuteorlando blog. Links the 90% claim back to Komanoff’s group Killed by Automobile paper. More links here on cycledog.

(more to come…)

See my own figures for manner-and-fault-in-bicyclist-traffic-fatalities-arizona-2009 which, according to the police reports/investigation, found motorists most-at-fault in about 50% of fatal traffic collisions between a MV and bicyclist in 2009.