If you're speaking of the P25 frequencies in the 760/770 range, those are used as mobile extender frequencies (replacing the former 154.905MHz analog frequency) for when the officer is out of his vehicle, also for area offices to talk to dispatch. I've tested and verified that these do work (driving near accident sites, area offices, construction zones, etc.).
As far as I know (and I could be wrong), the CHP will be staying on their 42/44 VHF range.
My guess is they just doing some updates on the frequencies in the radios for some reason, maybe utilizing the new planned WHITE channel that used to be listed in the database for the San Andreas/Amador offices.
But, then again, I could be wrong!
