AP Photo

Google has now proved that a self-driving car can travel more than 300,000 miles without a mishap. Well, it did suffer a parking-lot fender-bender -- but a human was at the wheel. Its customized Toyota Priuses use an impressive combination of GPS, radar, and a 3-D mapping camera on the car's roof that "sees" traffic signals, road lanes, and pedestrians in real time. Google (GOOG) is not alone. In 2010, as part of the VisLab Intercontinental Autonomous Challenge, four driverless electric vans made the 8,077-mile drive from Parma, Italy, to the World Expo in Shanghai. Last month California became the third state, after Nevada and Florida, to make self-driving vehicles street legal. (The catch, for now, is that a human must sit in the driver's seat, ready to take over in an emergency.) In...