I really like the Diddy Kong Racing approach and the vehicles look really nice.
However, i'm a bit scared when comes to three karts (Four for the super snowmobile which I assume is on land)* that are controlled on the ground alone. If that one surface (ground) is reserved for that one type vehicle, wouldn't all the other vehicles (ATV, Super Snow-Mobile*, Super-kart, and Hover-Cart) be able to travel on it just the same as a normal vehicle would with nothing to separate them other basic stats and design?