Thank you, Meswif. About the mentioned bug, it's actually not a bug. Hehe. It was intended to be that way to reflect the theme and let the player decide wisely which road to use to avoid borders but there is no guarantee a favorable road tile will be available.
During development I thought of wrapping the world around where if the car goes to north outer bound, the car will enter to the south outer bound. But I discard that idea thinking of the possibility of a bigger map and player must scroll all the way to the opposite edge within short time- it was 3s per player turn that time. Now it is 5s per turn, maybe that is enough time to consider this idea. And I'll probably let the player move the camera with mouse when cursor touched the edges of the screen for easier map navigation.
Let me know if this is a good idea. I will add it in todo list.