Don't know much about this aspect of transport in other places, but where I live all trams/buses (except night lines) go to the depot for maintenance only once per day, during the night. IMO it would be more sensible to have the vehicles return to the depot in this manner instead of after making every single round...
Here too. And I agree with you.
It’d be good if you create a line, and decide the timetable (like, I want a bus every ten minutes at peak hours and every hour at night, or maybe nothing at all at night, or only at night), then the game should tell you how many buses you need to have in order to have a bus every ten minutes (the moment of the day with the most frequent buses according to the timetable you made). At that point the line is open and buses leave the depo and go to the line, when the frequency is reduced, a few of them go back to the depo (and they’re available for other lines).
I know it is complicated, but the fact that every line has to go through the depo every time might be a bit weird.
Anyway, keep up the good work! I really like the day/night transition and the different number of pedestrians!