I believe the potential of Locomotion to play it like a road traffic simulation is pretty undiscovered (or did I miss any posted savegames? ), but can be fun. Of course, some things could be improved, for example traffic lights at small junctions (alternatively you need to modify all small junctions to small roundabouts to avoid unsolvable traffic congestions) and I wish traffic would be animated more fluid, but there's no other game offering this possibility as far as I know, because all games in this genre have only very simple roads, missing oneway-roads or wide curves that don't let you build interchanges and the more advanced simcity 4 rushhour has the problem that you can't control trucks and vehicles just "pop up and fade away" after a short time, which is killing most of the fun in my opinion.
Because building a small island with an advanced road system can be part of the fun, my suggestion is to use this thread as an invitation to post or show similar creations if you feel inspired. (perhaps I should change the thread title, suggestions?)
By the way, one trick to avoid buildings popping up at undesired places is to build roads like bridges in the editor and then simply raise the land under them.