For the 2005 race, DARPA has said the course will be at most 175 miles.  As for roads, because of environmental restrictions outside of their control (the desert tortoise for example), all or most of the course is over dirt roads.  The course can and most likely will cross active roads.  In last year's competition, one team was paused to allow a truck to cross the road.  The only external control allowed (actually, its required) is a 3-way control, RUN, PAUSE, and STOP.  If the vehicle is paused, the timer stops running for that team until they start running again.   12:08, 6 Jun 2005 (UTC)