The CB radio thing is going to be very location specific, I work in 911 dispatch, I think the state police around me theoretically monitor channel 9 on the highways, but in practice I wouldn’t have a lot of confidence in that, they barely look at info we send them over the computer, CB also has a somewhat limited range, so you’re counting on them having an officer somewhat nearby or you being close to their station.

As for local police, around me I suspect a few of them probably still have a CB antenna on the roof of their station and maybe even an old radio stashed somewhere in a closet but not hooked up and not being monitored, and the officers definitely don’t have them in their vehicles.

I’m in a pretty dense suburban area outside of a major city, they might still get some use in more rural areas where cell signals aren’t as reliable, though you’re probably going to run into the same issues with range limitations, in normal ideal conditions, you might get a range of about 20 miles or so, depending on atmospheric conditions, geography, etc. you might get only a fraction of that.