I don’t have time to figure any of this out, but in a nutshell, this sounds like a reasonable explanation;
The traffic fatality rates tend to be tied together (i.e. car vs. bike vs. ped), and…
high death rate places have faster traffic in general and vice versa.
Beyond Safety in Numbers: Why Bike Friendly Cities are Safer. The full published paper is linked, but i haven’t looked at it yet. (and i can’t open it on my android tablet?)
Why is AZ so deadly; and why does no one seem to notice or care?
Does, or could this explain the huge disparity between, for example, Arizona’s high traffic fatality rate and Massachusett’s extraordinarily low fatality rate? Check out the NHTSHA numbers here. Arizona’s rates are between TWO AND THREE TIMES as deadly as MA. Why?
These are composite traffic fatality rates, not bicyclist or ped or motorcyclist.
Safety In Numbers
Safety in numbers: more walkers and bicyclists, safer walking and bicycling P L Jacobsen 2003
Inj Prev 2003;9:205-209 doi:10.1136/ip.9.3.205