I just keep in mind that local city traffic means nothing.
City-to-City trafic is a key to get money. So i use local lines as a feeder to the long lines only. My local lines end on the long range station. Therfore I make local line as forth and back, never circular. I need to transfer people from their location to the long travel port. If they need to go buy a bread to their local shop, I dont care. If they need to buy a bread in the shop on the other side of map, well, thats interesting. 🙂