Playing the experimental simutrans, the following things occured to me:
1.
Citycars - maybe I'm not good at handling them, but at some point, on the traffic density 6 (perfectly manageable on Standard) the thing got a little out of hand. The cities were PACKED with them. But the worst thing was, the intercity roads quickly filled up with cars too ! About half intercity roads were one long queues of cars. The other half had only screen-sized queues on them. Deadlocks in cities started to get very common, and deadlocks that were not simply because cars got in some stupid want-to-go-around-the-monument deadlock, but because the cities were completely full of them. The problem is, I get the feeling that for each city house there were at least one or two cars out there (there were no "no route" passengers on stops, or at most trace amounts). That means each city produced more cars than there were roads inside the city. This gets unrealistic - normally you can fit more than one car in 1km of road
My proposal is to completely remove "random" city cars, and only spawn cars with destinations. I don't know how much it would help, but it should decrease the traffic a bit AND make it more believable. Do citycars with destinations disappear upon arrival at the destination ? If not, then it should be the case. I think the problem is not too high car generation, but the fact that the cars accumulate like crazy. Do the game keep track how many passengers actually are in cars and therefore can't appear again with another car ? Also, I'm not sure if passengers without access to cars generate them anyway if there is "no route". If it is so, then they shouldn't. Just too bad for them.
2.
Aircrafts. I stumbled upon a "problem" of sort. The speed of the aircrafts mean that their travel times are really short. Which make them really most preferred transport type with current routing algorithms. Like instead of taking train from Paris to Berlin, we will take plane... through Moscow. Because passengers don't pay for moving them away form their destination, they are quite happy to fly to Moscow and then to Berlin instead taking train that goes 1 hour longer. The problem is : they choose any route they want, but pay only for when they get closer. I want that too ! I would go from Amsterdam to Rotterdam through Shanghai, Los Angeles, Chicago and Paris ! What a trip... for almost free !
Well, enough problem exagarrating. I have a question : are loading times incorporated into "travel time" or "waiting time" ? If so, then I guess making most aircrafts extremely long-loading would cut the problem of them going there and back (a little ?). Alternatively, you could either put aircraft flight time modifier into simuconf file. The routing algorithm would consider all flight times this many longer
for routing purposes only.
Also, in long term it might be especially good for experimental to have paksets with first-class and second-class passengers (or however you call them). And there might be no planes for second-class passengers. Anyway, the issue is that good airplane network would steal all passenger traffic at the moment.
3.
Passenger routing - I know that passengers wait for specific line with best travel time to get them to destination, ignoring other lines that directly link them to destination. This is sensible, but I would add a tweak - compare not pure traveltimes, but
traveltime of currently considered line versus traveltime + averagewaittime of the "best" line
This way passengers would be less fixated upon taking specific line and if better option would suddenly present itself they would jump at it !
