Love this. Great physics engine and I love how much detail you put into the map and that I can go pretty much anywhere. I'd like to see a car reset button, though, as I do have a habit of ending up upside-down and I can't get my car unstuck D:
Might I suggest fixing the proximity of water/lava to the spawn point? I happened to spawn adjacent to a water block, and died before I could move. I know the level generation is random, but...
In a HTML5 version - http://www.kongregate.com/games/predbannik/carmyard-html5