Another problem with maps is that once you make them, you have to keep them up to date, a challenge Google says it hasn't yet started working on. Considering all the traffic signals, stop signs, lane markings, and crosswalks that get added or removed every day throughout the country, keeping a gigantic database of maps current is vastly difficult. Safety is at stake here; Chris Urmson, director of the Google car team, told me that if the car came across a traffic signal not on its map, it could potentially run a red light, simply because it wouldn't know to look for the signal. Urmson added, however, that an unmapped traffic signal would be "very unlikely," because during the "time and construction" needed to build a traffic signal, there would be adequate opportunity to add it to the map.
But not always. Scott Heydt, director of marketing at Horizon Signal Technologies, says his company routinely sets up its portable traffic signals at road construction sites. Frequently, they are simply towed to a site and turned on. "We just set one up like that in New Jersey," said Heydt. "You can be driving to work and everything is normal, but on your way home, discover a new traffic light." (Of this possibility, a Google spokesperson said, "We will have to be ready for that.")
Noting that the Google car might not be able to handle an unmapped traffic light might sound like a cynical game of "gotcha." But MIT roboticist John Leonard says it goes to the heart of why the Google car project is so daunting. "While the probability of a single driver encountering a newly installed traffic light is very low, the probability of at least one driver encountering one on a given day is very high," Leonard says. The list of these "rare" events is practically endless, said Leonard, who does not expect a full self-driving car in his lifetime (he's 49).
The mapping system isn't the only problem. The Google car doesn't know much about parking: It can't currently find a space in a supermarket lot or multilevel garage. It can't consistently handle coned-off road construction sites, and its video cameras can sometimes be blinded by the sun when trying to detect the color of a traffic signal. Because it can't tell the difference between a big rock and a crumbled-up piece of newspaper, it will try to drive around both if it encounters either sitting in the middle of the road. (Google specifically confirmed these present shortcomings to me for the MIT Technology Review article.) Can the car currently "see" another vehicle's turn signals or brake lights? Can it tell the difference between the flashing lights on top of a tow truck and those on top of an ambulance? If it's driving past a school playground, and a ball rolls out into the street, will it know to be on special alert? (Google declined to respond to these! additional questions when I posed them.)
Every unfinished piece of technology—every prototype, which is what the Google car is—has plenty of items to check off on its to-do list. But the biggest issue with the Google car is one that has bedeviled computer researchers for as long as computers have been around: how to endow the machines with the sort of everyday knowledge that humans acquire and use from childhood on. Because Google is promising the world a totally driverless car, it will need an in-vehicle computer that can deal not only with all the obvious tasks of driving but anything else the world throws at it, whether on a congested city street or a highway with an 85 mph speed limit.
Computer scientists have various names for the ability to synthesize and respond to this barrage of unpredictable information: "generalized intelligence," "situational awareness," "everyday common sense." It's been the dream of artificial intelligence researchers since the advent of computers. And it remains just that. "None of this reasoning will be inside computers anytime soon," says Raj Rajkumar, director of autonomous driving research at Carnegie-Mellon University, former home of both the current and prior directors of Google's car project. Rajkumar adds that the Detroit carmakers with whom he collaborates on autonomous vehicles believe that the prospect of a fully self-driving car arriving anytime soon is "pure science fiction."
Clearly, "autonomous driving" will increasingly be built into automobiles. One example is the "adaptive cruise control" offered now by many carmakers, which allows a vehicle to keep up with the flow of traffic. But it will be a far cry from having a Google-style computerized chauffeur.
We tend to lionize computer researchers, forgetting that they've made some colossally bad predictions over the years. When 2001: A Space Odyssey premiered in 1968, MIT's Marvin Minsky assured the public that machines like HAL would indeed be possible in 30 years. Perhaps one day tech enthusiasts will be able to visit a Museum of the Future That Never Was, where the Jetsons' hover car and the Google super-robocar will sit side-by-side as showcase exhibits. Expect long lines for both, because the demos will be sensational.
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