The Darpa Grand Challenge-not since the fabled transcontinental races of a century ago have so many engineers, professors, students, corporate teams, and garage tinkerers been drawn to so daunting a task. On the surface, it seems, well ... impossible. Once the race starts, the design teams can do nothing. There's no remote control, no driver. Using stereo cameras, radar, and lasers, the vehicles themselves must check for obstacles, then roll forward at speeds up to 60 mph, across sand dunes, through valleys, along highways, and over rivers, all the while obeying the way-points beamed to them from global-positioning satellites.
