Sorry to double post, but I'm amazed that I seem to be the only one here who knows of this gem.
I mean, just look into the level of detail he puts into his writeup on the pathfinding algos [1]. SC4 is a whole region simulator with multi-city economics in play. Runs in Linux on Wine. Best damned $20 I ever spent.
There is (or was, I suppose) a vibrant and diverse community of SC4 modders. Really cool stuff to be found there.
[1] https://sc4devotion.com/namdoc/feature-guides/traffic-sim/tr...