Three years ago, news stories all but laughed aloud at the driverless vehicles in their now-famous race across the Mojave Desert, as they gamely tried to cross a 142-mile desert course on their own. In “comic” fashion, the stories said, the robotic vehicles drove in dizzy circles, stalled atop rocks, and slowly halted themselves, apparently confused by the breadth of their electronic chores. As if on cue, a robotic motorcycle added to the already-mirthful tone of the day by traveling just two feet before toppling over. A San Francisco Chronicle headline summed it up: “Robot race suffers quick, ignoble end.”
How times change. On Oct. 8, 2005, just 19 months after that “quick, ignoble end,” five driverless vehicles stunned the American public by crossing the finish line in the second DARPA Grand Challenge. Stanford University’s Volkswagen Tourag – dubbed “Stanley” by its designers – crossed the rock-strewn, 132-mile course in an astounding six hours and 51 minutes. Three others completed the off-road course in less than eight hours; a final vehicle finished in 12 hours, 51 minutes.
The unspoken lesson was obvious: Robotic technology was advancing faster than anyone had imagined. Moreover, during the ensuing months since that second government-sponsored race, many have come to believe that engineers might yet prevail in an effort to put autonomous vehicles on our roads in the next quarter-century.
“The biggest thing ‘Stanley’ taught us is that autonomous cars are really possible,” says David Stavans, a Ph.D. student at Stanford and co-creator of Stanley, which won a $2 million purse on that day. “Stanley drove flawlessly in the Grand Challenge, and in the national qualifying event, and for many hundreds of miles before the race.”
To be sure, it wasn’t easy. Most of the robotic driving was on an off-road course strewn with obstacles, natural and man-made. Sensors, microprocessors, and software struggled to recognize roads, let alone rocks, ruts, tunnels, bridges, tumbleweed, fence posts, barbed wire, competing vehicles, and mechanical traps that the Defense Advanced Research Projects Agency (DARPA) had laid out for them. Still, Grand Challenge engineering teams were supposed to make it happen with off-the-shelf hardware.
“It was like teaching a baby to walk,” says William “Red” Whittaker, Fredkin research professor of robotics at Carnegie Mellon University, and team leader for the school’s two race entries. “At this point in history, computers simply aren’t as competent at driving as humans are.”
Still, some robotics experts believe that robotic vehicles could one day be up to the task of controlling everyday transportation, given their extraordinary pace of advancement. If that’s so, robots will one day enable drivers to snooze or read while their vehicles drive them to the office.
The greatest challenge in making that happen, however, may arrive in the earliest years, when robotic vehicles will undoubtedly share the road with aggressive and unpredictable humans.
“Being able to drive in traffic is a much harder problem than the vehicles faced at the Grand Challenge,” Stavens says. “The biggest problem is other drivers. The robot has to use reasoning to predict what other drivers will do.”
Moreover, many experts warn that social and legal obstacles could prevent robotic cars from reaching the road for many, many years. Most drivers are likely to distrust machines, at least in the beginning. Moreover, our increasingly litigious society is likely to make automakers balk at the thought of taking responsibility for the operation of a robot.
Still, many high-level engineers believe the technology will be available and reliable long before society expects it, which is why the Defense Advanced Research Projects Agency (DARPA) is sponsoring a 2007 yet another robot race – this one across urban terrain. Known as the DARPA Urban Challenge, it will force the robotic vehicles to interact with city traffic. Participating vehicles will have to change lanes to pass slower-moving vehicles, stop at traffic lights and stop signs, and do virtually every task that city drivers do on a routine basis.
Stanford’s 50-member engineering team for the race believes that machine-learning may be one of their biggest keys to success, as well as in eventual efforts to put robotic vehicles on our roadways. The team used the same strategy in the development of Stanley, which incorporated more than 100,000 lines of computer code to examine old driving data, which enabled Stanley to learn whether it should stop, swerve, or just keep moving when it “saw” a potential obstacle. As a result, Stanley didn’t pause to “hallucinate” as some other vehicles did when they thought they saw obstacles in their paths.
Ultimately, the birth of autonomous vehicles may also benefit from the parallel emergence of smart highways, which are already being discussed by automakers, electronics companies, and government agencies. Using a concept known as a Dedicated Short Range Communication (DSRC) system, the new smart highway will employ a 5.9-GHz transmission frequency to enable roadside transceivers to talk to vehicle-based transceivers and GPS units. By knowing the number, location and speed of nearby participating vehicles, the system could create a local area network in which vehicles and traffic lights will share data.
“You could put one of these radio devices at a traffic light, stop sign or intersection, and it could broadcast information to approaching traffic,” says Bob Lange, executive director of structure and safety integration for General Motors Corp. “In the event of a collision threat, it could alert drivers. In extreme cases, it might even be aggressive enough to intervene and apply the brakes or steering.”
To be sure, DSRC isn’t being targeted at autonomous vehicles. But some engineers see it as a piece of the puzzle that might one day speed the development of robot cars.
“That’s a very important part of making autonomous vehicles a reality,” Stavens says. He adds that it will serve as a good way to reliably detect what’s happening at traffic lights and on roadways across the country.
“The goal is to create a system that works well and is safe,” Stavens concludes. “Certainly within 20 years, and maybe even in ten, we will have autonomous cars capable of driving reliably on any kinds of roads.”
Get more information about DARPA’s 2007 Urban Challenge