Wednesday, January 27, 2010

Pedestrian Deaths and Weather

The GTA has experienced 14 deaths of pedestrians in traffic so far in January 2010. It is natural to ask why so many deaths, and why now. Of course, as Dylan Reid points out, there are a lot of factors likely involved, including the rise of smartphones and other devices that can distract pedestrians, and the sorry state of Toronto infrastructure at resent. But none of this can explain the sudden rise in deaths. A more plausible explanation is the weather: it's been too damn good this month, which is likely to bring more pedestrians out on the streets. Could that, coupled with winter driving conditions, and the fact that drivers are not expecting pedestrians in such numbers at this time of year, explain the difference?

The figure below charts the daily maximum temperature this month and in January 2009. Temperatures are indeed higher -- the montly average is -1.1C, compared to -4.6C last year. Furthermore, notice that the real rise above seasonal normals occurred around January 12 -- and 11 of the 14 pedestrian deaths (marked by yellow bars on the chart) have occurred since Jan. 12.

Again, no one factor can explain what is happening, and there is doubtless just some collective bad luck involved. But the linkt o good weather seems pretty clear.