Fish & Game dispatches their own calls during business hours. Wardens are in contact with some of the county sheriff's dispatchers at night, on weekends and holidays. I've never heard any car-to-car traffic with local law enforcement agencies.
Cal Trans and the State Parks are using a conventional 800 MHz system; while the prisons and universities are trunked. The CHP is almost alone on the VHF low band. Not likely that everybody will get on the same page any time soon.[/QUOTE
Many Wardens are in contact with allied agencies during the day as well. I have handed out more than a few UHF antennas and 800 MHz radios to Wardens who want to be able to talk to people other than DFG and CDF. A friend of mine just helped strip a Parks truck and is putting the 800 MHz parks radio into his patrol truck. That is interoperability.
Caltrans still uses the lo band, more so in some areas than others. Not all of the universities are trunked, not all of them are on 800 MHz either.
When I used to work with State Parks frequently (before my retirement) they had a Midland 80 channel VHF radio with local sheriff's, PD's, BLM, USFS, NPS, etc. The program was identical with that of DFG's.
Someone related that CDF and DFG have coverage in the rural areas. The DFG coverage is getting better as they slowly add some repeaters, however there are some areas, some significant, that don't have coverage.
CDF has coverage in the counties that they have SRA in. The contract counties don't have close to the coverage CHP would need. In Mono County the CDF repeater coverage is not good at all. CHP has fair coverage of the paved highway portion of the county, but not in the many large dirt road only areas, such as the area east of Bridgeport. To cover all of Mono County with 800 MHz would require at least 7 additional repeaters, perhaps more. These sites are not currently state sites with electrical present and would be difficult to link to the State's microwave linking system. CHP only has 4 repeaters in the county now. The Caltrans 800 MHz system has a lot of blind spots that the CHP could not tolerate due to officer safety issues. Inyo County would require about 5 more, adding to the 4 that exist now. So more than a doubling in Inyo/Mono with at least 12 more needed as the 8 existing won't do the job. Some of these new sites are quite primitive with all solar/propane facilities, a single low level antenna (short mast or with no mast at all) and vaults that may not allow techs to enter as they are really just metal boxes that are less than 6 feet in height. Some don't have any other users of the site except the BLM, NPS, and USFS. Some of those may not be available for the state to use due to environmental issues such as not being able to build a road to the site and not being able to place larger buildings and more substantial antennas (towers instead of short masts).
Other rural and mountainous counties would have similar issues. VHF trunking would have the same number of sites needed. Rural counties on the west side of the Sierra may have good VHF and 800 MHz coverage as the State sites to the west such a Joaquin Ridge provide pretty good coverage for the mountains. Take a look at the NPS, BLM, and USFS in the database and you can see how many repeaters are needed to cover an entire unit under their jurisdiction. Many or most of these repeaters are needed just to cover the roaded sections of those units. Very few repeaters provide coverage to wilderness areas alone. Coverage in those wilderness areas is not all the great anyway.
Give these factors I see some significant obstacles for the CHP trunking using VHF or 800 MHz. By the way I've seen better terminology used for the 700/800/900 MHz bands. It is called UHF high with a corresponding UHF low designation for the 400/500 MHz band. With trunked and simplex systems on 700/800 MHz's it sure would be nice not having to refer to these bands by their frequency range.