It's Police LS, LV, SF by GTA:SA side, however outside the game they can be used by much more. LAPD for example doesn't only use Crown Vics, they also have Chargers, Impalas (I guess), Explorers, Tahoes, etc. If you look into the default car mods you'll see each has their own shader which displays the department you spawned in, for example if you spawn in Red County your cruiser will show "Red County Sheriff Department", LS will show "Los Santos Police Department", etc. In addition, leaving Police LS, SF, LV to all departments also allows people to mod the game how they want (for example mod all 3 of the cars into LAPD car mods, etc.) After stating these facts I will have to respectfully deny this suggestion.