At first, Sebastian Thrun didn't feel quite comfortable behind the wheel of the modified Volkswagen Touareg R5 named Stanley. That's understandable, because he wasn't driving. Stanley was. As the Stanford University entrant in the DoD's Defense Advanced Research Projects Agency's (DARPA) $2 million Grand Challenge, Stanley was designed to compete against 26 other driverless robot vehicles in a race through 132 miles of hostile terrain in the Mojave Desert. On test drives (the real race would be run with no passengers), Thrun had a red panic button to stop the car when Stanley failed to notice a sharp turn, or swerved toward the brush to avoid an obstacle that wasn't there. After months of software tweaking, Stanley got so good at driving that Thrun, head of Stanford's Artificial Intelligence Lab, relaxed, even allowing himself to gab on a cell phone or consult his maps while Stanley made its way through tough desert roads. Thrun and his team began to think that on Oct. 8, Stanley might complete the DARPA challenge.
That was an achievement that many observers considered possible only in the distant future, if ever. Computers, despite success in e-commerce, data mining and chess, have behaved like utter idiots when it came to getting from point A to point B in the real world. Only a year and a half ago, in the first DARPA challenge, the robots promptly drove into rocks or bushes or simply died at the starting gate. The best effort was from a Humvee that went seven miles before steering itself into a drop-off, its front wheels grinding helplessly in the air. This year was different--and historic. There was a winner: Stanley, which completed the course in six hours and 54 minutes.
What's more, four other empty vehicles also triumphantly made it to the finish line, avoiding gullies, making tight turns, scooting through tunnels and, finally, navigating the treacherous twists of Beer Bottle Pass on the route's home stretch--all without a hint of human intervention.
What was Stanley's secret? According to Thrun and Mike Montemerlo, a postdoc who was the software guru for the Stanford team, this robot had the ability to learn about the road. Its sensors gathered information about what was underneath its front bumper and used that knowledge to figure out what was road and what was not road for hundreds of feet ahead. Also, when it came to figuring out what should be avoided and what could be ignored, Stanley was trained to emulate the behavior of human drivers. After that, says Thrun, "the false positives [incorrectly identifying an obstacle] went from 12 percent to 1 in 50,000."
Thrun is the first to admit that Stanley and his robot kin aren't ready to negotiate the "dynamic environments" of L.A. freeways or New York City cross streets--yet. "It's like walking up to the Wright brothers and asking them if their plane could fly across the Atlantic," he says. He believes that winning the challenge is a milestone toward a development he thinks is inevitable: the day we'll be able to turn the keys of the car over to... the car. In a few years, he predicts, we won't drive into the parking garage--we'll get out and let the Chevy climb the ramps and squeeze into a space by itself. Eventually--20 years? 30 years?--you're reading the paper during the commute, and on family trips you're in the back seat with the kids, watching a DVD. Meanwhile, the Pentagon is more than eager to make use of self-driving robots--that, after all, was DARPA's explicit objective. The goal is to have a third of the military's land vehicles driving themselves by 2015. For human beings driving in convoys in Iraq, the robots can't come soon enough.