"CB radio scanners"
Not CB radio. We (on this side of the pond) have available VHF/UHF analog/digital trunked radio scanners. And not many police departments encrypt their traffic (it decreases their comms reliability). Even an SDR dongle and some clever software will get you a good bit of the way there.
There are some streaming audio web sites that rebroadcast police and fire radio traffic. So you don't even need to invest in a radio.