Gibsonia is the PSP T Barracks for District 1. Their units are IDed by Gibsonia X (usually a low number). 8100 units are usually the maintenance trucks and sometimes the State Farm patrol units. They also can be 8200 at times.
PSP can be identified by the end tone after their transmission. Sounds like a cricket.
This is all I know for now.
Maintenance crews and the State Farm patrols trucks all ID just like the troopers...facility name followed by a number. All of the 8000 series numbers are contracted service facilities that do towing of vehicles off the pike , tire changes, etc. 7000 series units are contracted emergency services (fire and ems companies).
Each of the five districts is broken up into patrol zones. While I have never paid much attention to the numbers, it did always seem that the zone numbers increased sequentially from the west to the east across the state. My guess would be that each zone covers a 10 or so mile stretch of the highway or some segment between two turnaround points (for ease of patrol).
I'll start paying attention to the zone numbers given by troopers when I am listening.