Yet another update!
It took me a week, but I managed to implement elevated outer loop (think Wangan expressway in Tokyo).
There was a surprising amount of things that needed changing for this to happen: I had to implement slope for curved roads, then include negative slope too, then connect all the roads to their intersections if either the road or intersection was elevated, spotted an issue where some straight road meshes left holes (fortunately was a straightforward fix because the mapgen code is the opposite of simple), then fix physics as it turns out convex shapes don't work with curved/spiral meshes so I had to do series of box shapes, then implement stairstepping as colliders weren't perfectly lined up and the car could get stuck even before I did the box shapes trick... and on top of that I had to implement procedural POI placement because I now had to exclude all the elevated intersections (a garage or a dealer floating in the air looks just silly)
Finishing all this warranted another merge to 4.x branch, and next... likely saving/loading the game itself since the map is now interesting, events reset every day and there is stuff to do!
