The cars would crash at different spots even with no variables changed. Idk what is causing this, but between this and the fact that the game doesn't show where the crash happened unless I happen to be looking at the intersection when it happens means that I would occasionally "solve" the puzzle without knowing what I did or even not doing anything different at all.
With these things fixed and a lot of fleshing out artwork and sound-wise, I think I would enjoy this game a lot. It is fun to build complexity incrementally when it works and see the whole thing moving smoothly. There's something satisfying here, but not yet.