Anecdotally...
Having spent time driving in both Europe and Southern California, I'd say that European drivers are more attentive to their driving and way less likely to be looking at their phone while driving, since it's policed. You can often see drivers in SoCal holding their phone for a video call.
In downtown LA I routinely spot on-duty police officers, who are usually cruising in large SUVs, texting while driving.
Everyone around the world seems to eat cereal while driving:
https://www.bbc.com/news/uk-scotland-edinburgh-east-fife-614...
https://www.cbs42.com/news/crime/ohio-woman-caught-eating-ce...
https://www.carthrottle.com/news/cyclist-berated-woman-eatin...
I’m pretty sure I’ve seen drivers in the Bay Area conducting a full blown Zoom call, video and all.
(I used to have a corporate laptop I put a 4G WiMax chip in, and would boot it and connect to corporate VPN, open Lotus Notes, and then start my one hour commute. Then at work my Notes would be fully sync’d which otherwise took a half hour.)
One thing I was surprised by when driving in Coquitlam where I have cousins is that drivers there would start moving right after the green. This is strange to me because drivers in San Francisco will frequently be stationary for seconds afterwards. Looking at the rough statistics, it appears the RCMP police for smartphone usage in a stricter manner than SFPD does (or at least they write more citations) which makes me think that drivers in that region have adapted by not using their smartphones as much.
I wonder if this metric of "traffic light change to driver action" delay is a thing we could use as a performance metric for how well cities are ensuring smartphones aren't used by drivers.