Some people like to role play a little bit, so, using the LA mod as an example, they put CHP on the highway, and have other police cars and whatnot setup around the city. I usually save a freeplay game that has the setup I like as soon as I set it up, that way I can just start a new freeplay game with the setup already done and not have to do it again. With the maps switching during the game in this mod though, it won't really be that big a deal.