Well, I tried UPS and it works well for creating civilian people walking inside the city. It also works with cars which are driving inside the city. But I can't make cars to drive from one city to another city and back. Cars can only drive into one city direction, eg. from city1 to city2. When car arrive in city2, it will drive inside the city2 forever, but will never return to city1. It will be nice if cars can drive for example from city1 to city2-city3-city4 and then back to city3-city2-city1, or drive randomly from city to city. :)