I hung out in Aldan last night for a couple hours but wasn't able to pickup any close call hits at all. I also could not find any hint of anything in the FCC database. It's worth noting that the cars have 2 identical UHF antennas on them, so my guess would be whatever it is resides in the UHF band. I'm thinking it's a leased frequency, maybe from one of the local communications companies. Problem is, without peeking inside the car there's no way to tell if it's analog, digital, conventional or trunking. The other possibility is that they aren't using radio at all, but rather a "channel" on an app like Zello.
My father-in-law lives in Aldan, and I'm tempted to setup a remote scanner with one of my Uniden scanners and Proscan and see what I can come up with. I know he wouldn't mind.