This ponderously-name technical report from the NHTSA, Incidence of Pedestrian and Bicyclist Crashes by Hybrid Electric Passenger Vehicles [DOT HS 811 204 pdf here]
Has a bunch of interesting tidbits. It’s obviously leading or suggesting that quieter motorvehicles, particularly at low speeds where tire noise would be less significant, have a tendency to not be heard by cyclists or peds thus leading to more crashes. Sounds plausible. The difference may explain some human behavioral factors of operators of bicycles; such as why cyclists rarely make a complete stop, yet rarely get seriously injured in those situations. (Motorist, too, rarely stop but that’s another story)
What mainly caught my eye was a juicy dataset as describe in the METHODS section “State crash files from NHTSA’s State Data System (SDS)… The SDS includes all police-reported crashes, regardless of the injury or crash outcomes”. Though the SDS actually only contains records for 32 states, arizona not being one of them.