Hi, based on my observations:
-what is better : a round-trip or to a point in town and back the same way
I usually make use of point to point running through the center of the town (covering 2 or 3 zones) to the station. Than I make a second line to cover the missed out zones. I usually get 80+ line usage. It all depends upon the town structure. In some towns I have a successful circular lines
– how to take land use (red/yellow/blue/green) in considaration?
People travel from one zone to another. There is no specific destination. As long as your zones are connected effeciently, people will use your lines
– how to take land value in considaration (bright versus dark colors)
I usually place stops at the end of intersection, near bright areas to get maximum passenger. However, in the future, you will want to place stops near darker zones as well, in order to develop them
– what spacing between stops?
Depends upon how long is the road intersection and road network. Placing stops where various roads meet is a good idea. Avoid placing more than one stop in a single intersection provided that it is not toooo long.
– how many stops on one line?
Depends upon the size of the town
– should all lines start/end near the railway station?
– how many lines in a town?
I usually have 3 lines (1st is profitable, 2nd is profitable but little 3rd is break even or loss
– how many vehicles on a line?
Depends upon the line lenght, maintaining a correct frequency lets say 30 to 60 seconds is more important.
I hope this was helpful