I cant answer all your question but I’m very surprised about Tucson’s place on this list. I spent a month there this winter, finding a biking paradise.
There is an extensive MUP system. Bike lanes on almost all major streets. A number “Bike Boulevards” which are routed through quiet neighborhood streets, well marked with sharrows and signs, special protected crossings of major roads, traffic calming features.
The only explanation I could guess at is that the arterial roads are motoring madness. There always is a bike lane, but there are many motor traffic lanes in each direction and people drive super fast. As many as three left turn lanes at some intersections. Road surfaces are very bad.