After an extensive rewrite of the field handling, i am proud to say that the functionality of both the road and the cars are now working! i'd have to tidy up some of the 3d shapes but everything is being auto-layered via script so it won't look stupidly out of place. oh and there's a cheat script in place that you can easily disable.
rename as needed.
edit: got to reupload it
Edit 2: as of further testing there's very minor bugs but still very usable. 3dn
Edit 3: screenshot added