There were other things wrong with CiM, but the busses were terrible.
In real life you can obviously make a route go on whichever road you want, for example if there are busy streets, I want to make my bus take the highway instead. But in Cities in motion you can do that because they overlooked a huge game feature, so your bus only went automatically-generated routes between stops that the game workd out automatically.
Stupid, even Traffic Giant didn’t screw that up and that game is like over a decade old now.