Separate California and Nevada Highway Patrol cars
This mod turns the generic police car into California Highway Patrol, and adds a separate Nevada Highway Patrol car. Each appears in their respective state. The city police cars still appear in San Francisco, Los Angeles and Las Vegas.
One issue: Some areas on the map have parked police cars, e.g. on the road to Jackpot, Nevada. Those parked cars will appear as California Highway Patrol. It would require editing the maps to change this. I invite someone to do so.
Also, I'd like it very much if someone could make proper black-and-silver wheels for these police cruisers. They do look a little silly with the default BMW rims on them.
I'm sure there's a more efficient and elegant way to achieve what this mod achieves, but I've done it the only way I could figure out how. I'd love it if someone could slim it down -- and prepare it for adding Arizona Highway Patrol (since, when Arizona comes out, the California Highway Patrol will be policing that state, so I'll need to update this as soon as Arizona is released).