Hi again. Some more ideas for you. Hope they're helpful:
1. Gridlocked cars obscure the coloured traffic light arrows. Maybe the coloured arrows could be overlaid "on top" of the cars so they are always visible?
2. The "Final Report" window obscures the final scene, showing which cars/junctions are having problems. I wish I could move it out of the way.
3. With the saved maps/layouts slots, it would be useful if they were labelled with the score they achieved (if any).
4. I really want to know if anyone can beat my scores! It would be great if users could upload their best score, so the "Final Report" could say: "The highest score so far is 21,320."
5. Regarding AI/game logic, a user below said below that the cars aren't "crashy" enough in the latest (v0.21) release. As you said, it's a delicate balance to get right. I think the most important thing is that the best solutions make logical sense, and don't rely too heavily on random trial-and-error. For example:
In the screenshot below, no cars are routed via the circled traffic light. I can set that light to all red, or all green; or remove the light, or even remove the road square it's on. I always get exactly the same score of 20,000, which makes sense.
But, if I set that traffic light to 1-on/1-off (x6), to match the lights above and below, I get a score of 20,900. If I set that light out of phase (by rotating the wheel once), I get a score of 20,700. That doesn't seem logical.
Then again, the restricted budget limits these "hacks", so maybe the possibility of discovering these illogical "Easter eggs" is intentional? Or maybe I've misunderstood how the cars could stray into (and immediately out of) that lane, and how that might affect collisions...? In any case, it's a very minor quirk that probably doesn't matter, but I thought I'd mention it.
Best wishes :-D