Will my bike hitch fit on any car?
As for the vehicle most buyers need only consider the size of hitch they have, 1 1/4" or 2" are the typical sizes and try to get a hitch of the same size. You can usually get an adapter to fit a rack that is sized differently than the hitch. 

Typically the hitch racks sit a bit back off the rear of your car to accommodate rear features of most vehicles. I'd only be worried if they had a spare tire mounted on the rear of the vehicle.