Something to think about...a huge project it would be. So imagine, you get in-game, load your EUP character up, got your car ready, and you "force duty" or whatever into the game, and all of a sudden, you have ambient patrol units that spawn around you say the size of the whole Vespucci area. The catch is, those units are persistent, and say you don't answer a call via lspdfr, they take it. You drive to their location, and they are active in something, maybe talking to a pedestrian on the street, or walking around. Doesn't have to be perfect, just for the immersion. And while that's going on, the other units driving around may pull vehicles over. If you call backup, they actual drive from where they were and respond, giving you a limit on how many backup units you can get. Even have a parked air unit on standby. Make an XML file listing how many units for the shift, distance they spawn from you, give it a minimum distance so they don't all spawn in your face, their unit call-sign, type of unit, how many officers in unit, the area in which they are restricted to (i.e Vespucci division, Central LS division, Rockford Hills division, Le Mesa division, LSIA/Port division).
I know it would be a big project but it be something that would take immersion to the next level. It could tie into Police Computer, LSPDFR+, LSPDFR main code, and so many other great mods.
Let me know what you guys think.