I would love to see a feature added whereby you could customise the maximum distance a certain unit is able to respond. For example, I believe (although am happy to be corrected) that Civil Nuclear constabulary (CNC) officers have jurisdiction up to 5 miles radius from the site they are meant to protect. It would also be handy for limiting the distance airport units were able to respond etc...
I am not suggesting you are able to override the maximum distance a vehicle is allowed to respond but to have the option to reduce it based on real life would be a nice addition to the game.