To add to this. The first DARPA Grand Challenge was held a little more than 18 months ago. At that time no one completed the race. CMU's Sandstorm went about 7 miles and then crashed out of the challenge. None of the others even came up to 7 miles.

I was working under one of the CMU Prof's who also happened to be one of the external technical advisor for Sandstorm. The reason he gave for the crash was the technical people behind Sandstorm did not forsee the following situation: Encounter a curved uphill slope.

So apparently Sandstorm did not reduce its speed when it encountered the curved uphill slope. Hence it jumped the tracks, which lead it to crash and eventually one of the wheels caught fire.