Calgary Collision Comparison

Gian-Carlo Carra asked at the SPC LPT meeting on the Cycling Strategy if anyone know "how dangerous" it is to ride a bike relative to driving a car.  I don't think anyone does know this, certainly not for Calgary,  We have collision statistics for bicycle-involved collisions, though, and the CPD's annual reports contains overall collision numbers.  They only have annual reports for 2007 and 2008 online, so numbers for 2006-2008.  These are reportable collisions under the Alberta Traffic Safety Act, so they all involve at least one motor vehicle.  I don't think there are numbers available for how many injured persons there were, broken down by road user class.  But: almost all the injuries and all the fatal injuries in bicycle-involved collisions were sustained by the cyclists involved in those collisions.

I'm not sure what conclusions to draw from these stats.  I think it's safe to assume that the ratio of distance covered by bicycles/distance covered in cars by Calgarians is nowhere near 5.8%.  So per km travelled, it's probably safer in a car.  Not sure how the rate compares to time spent on bikes/time spent in cars or number of trips by bike/by car; probably still higher by a factor of 2 or so.  But the main problem is that this all counts numbers of collisions and not numbers of injured, and we don't have the breakdown by road user class.  In 2008, for all of Alberta, cyclists amounted to 2.4% of all injured, pedestrians 5.7%, and drivers and passengers for almost 70%.  But in an urban area, the percentage of pedestrians injured is probably going to be much higher.  Also note that children under 16 make up a quarter of the injured cyclists; they don't make up nearly as high a share in the persons injured in collisions overall. 

This recent article from the Guelph Mercury states that there are 27 bicycle collisions per year per 100,000 resdents in Calgary; that's a lot higher than the numbers I came up with.  It also has us a lot lower than Montreal and Toronto: but there the ridership is also much higher, so no surprise there.

Here's an interesting site about the risk involved in cycling.

  2008   2007   2006  
  Total Per 100,000 Total Per 100,000 Total Per 100,000
Injury Auto 3019 278.5 3369 316.6 3600 347.9
Fatal Auto 37 3.5 39 3.7 46 4.6
             
Injury Bike 177 16.3 157 14.8 190 18.4
Fatal Bike 2 0.2 1 0.1 0 0.0
             
Injury Bike/Auto 5.86%   4.66%   5.28%  
Fatal Bike/Auto 5.41%   2.56%   0.00%  

Forums: 

Depends a lot on how you measure

For example, I've seen one comparison (ah, here it is) where the numbers look pretty bad for cyclists if you do per-kilometer (``Pedestrian fatalities are 36 times higher than car occupant
fatalities per km traveled, and bicycling fatalities are 11 times higher than car occupant fatalities
per km''). He does a per-trip analysis, but doesn't compare that to cars (only US vs Germany vs Netherlands for walking vs. cycling). Really, it's not surprising (to me) that the per-km stats show pedestrians at a huge disadvantage to cyclist who are at a huge disadvantage to drivers: it takes a lot longer to walk than cycle and to cycle than to drive the same distance.

Note that Germany has about 4 times fewer fatalaties per billion km for cyclists. Nonetheless, even per hour (if we arbitrarily say cars are about 5 times faster than cycling) cycling comes out more dangerous in the US (about 2 times). In Germany, cycling is about half as dangerous (if cars are 5 times faster, on average, than bikes).

Here are some more random links:

decent article in Grist including an assertion, ``In Vancouver, B.C., during the period in which the number of cycling trips has almost tripled, the number of insurance claims involving bicycle collisions hasn't budged, according to the Vancouver Courier (sorry, the link is no longer available).''

UBC overview, with references.

A fairly weak wikipedia entry, mostly with UK stats.