I know a few FHP troopers use scanners "unofficially" because their system is a nightmare when it comes to interoperability.
Worked the other way around when I was a dispatcher....
"Radio, do we know why we have a half dozen troopers running code down the interstate?"
"Stand by, we'll have a call taker give them a ring."
*10 minutes later*
"They're pursuing a homicide suspect, but they're already in the next county."
The state patrol in Iowa does. Not sure on the model, but in recent years they have switched from a 5/8 wave VHF antenna to a tri-band antenna so they can listen to more counties as everything is going there own way now. Iowa was all VHF-Hi analog for a number of years. Now we got PS on VHF analog/P25, UHF conventional, 800 conventional, 800 P25, and operating on private 800 systems. Where I grew up, nobody had scanners, every had everyone else's OPS channels in their radio. Where I'm at now, they have scanners and some of the officers have to buy their own if they want one.
Here in South Dakota Highway Patrol and Game Fish and Parks carries the Radio Shack Pro 197. Most of the state is on VHF digital Motorola type 2 smartzone trunked system, but some counties either have agencies that havent bought the radios because of cost, but most counties/agencies that are without the digital radios becuase they dont have decent tower reception
I would think it would mostly be in rural areas or in places that allow you to take it in car when you done work.There is a myth on TV that taxi cab drivers and state troopers are the only one that seem to do this!!
But now with use of the cell phone and laptop use many PD are not using their radio much other than priority E and priority 1 calls.