In our case, the guy went through the arborvitae hedge (destroying
about 4) and was stopped (very luckily, he probably would have kept
driving into our livingroom) by the fact that it had been raining and
our front yard has poor drainage - he sank up to his axles in the
ground. So if it happened a lot (it doesn't this was just an
exceptionally skilled drunk) I would probably go with a similar mud
trap - or water feature. I think a good thick mud would absorb most of
the energy. Mythbusters made a quicksand tank - maybe that would work.

First time I've ever called the cops on a guy...