In all the talk of graphical downgrades no one seems much preoccupied with 'why?'. Why build something and then proceed to tear it down, piece by piece, in the hope that ever more diminished expectations about the final product won't be severe enough to...
Play the tutorials - otherwise, you'll have no idea what's going on.
Crossing roads can make your drivers confused. Lift them over each other instead.
Check that the catchment areas of your goods stores are actually in useful places.