When I came to Oregon after forty years split between the SF (L)East Bay and the Sacramento Valley, it was a shock. I briefly stopped riding altogether due to the overly hostile motoring public. After a while, I saw the way it was working and got back in the saddle, but it's still more stressful than NorCal.
Hereabouts, when I go out for a training/joy ride, I always wear a bright reflective vest (we call then newbie vests), reflective ankle straps and at least one bright blinkie, sometimes a Dinotte 400R. About one-third of the motorists pass me illegally with about 5% of them passing close enough that it is uncomfortable/stressful. When I ride back in NorCal, which happens several times per year, I just wear what I want and rarely put a blinkie on the bike for daytime riding. The motorists almost all change lanes to pass and I don't even consider the possibility of getting hit. There's also a LOT more intercity cyclists in NorCal than there are in Oregon and that may be a factor.
Other parts of the country that I have ridden in have been a mixed bag. Oddly enough, I found Lubbock, TX to be quite bike-friendly/tolerant, at least as far as the behavior of the motorists. Perhaps it was just their shock at seeing someone on a bike that led to that. However, if that was the case then I can't explain Pittsburgh; what an angry city.