[marssaxman]

That was true for the first two Grand Challenges, but once that prize was claimed DARPA simply cranked up the difficulty level; the 2007 race was all about navigation in urban environments, and compliance with traffic laws was a condition of success.

Sure, of course you're right that "the bulk of the work" is not related. But it's also no secret that the "sudden spike in interest in this technology" lucker referred to above happened because the US government paid for it to happen, as a means of advancing military vehicle automation technology.