Anyone driving the twists of Highway 1 between San Francisco and Los Angeles recently may have glimpsed a Toyota Prius car with a curious-looking thing on the roof. Harder to notice was that the person at the wheel was not actually driving. The car is a project of Google, which has been working in secret but in plain view( anyhow, no one can keep such a thing from the public) on vehicles that can drive themselves, using artificial-intelligence software that can sense anything near the car and imitate the decisions made by a human driver. With someone behind the wheel to take control if something goes wrong and a technician in the passenger seat to monitor the navigation system , seven test cars have driven 1,000 miles without human intervention and more than 140,000 miles with only occasional human control. One even drove itself down Lombard Street in San Francisco, one of the steepest and curviest streets in the nation. The only accident, engineers said, was that one Google car was rear-ended   when it stopped at a traffic light. Autonomous cars are years from mass production, but technologists who have long dreamed of them believe that they can transform society as profoundly as the Internet has. Robot drivers react faster than humans, have 360-degree perception and do not get distracted or sleepy, the engineers argue. They speak in terms of lives that could be saved and injuries that could be avoided--- more than 37,000 people died in car accidents in the United States in 2008. The engineers say the technology could double the capacity of roads by allowing cars to drive more safely while closer together. Because the robot cars would eventually be less likely to crash, they could be built lighter, reducing fuel consumption. But of course, to be truly safer, the cars must be far more reliable than, say, today's personal computers, which crash on occasion and are frequently infected.    The Google research program using artificial intelligence to revolutionize the automobile is proof that the company's ambitions reach beyond the search engine business. The program is also a departure from the mainstream of innovation  in Silicon Valley, which has turned toward social networks and Hollywood-style digital media. However, the Google researchers said the company did not yet have a clear plan to create a business from the experiments. The author's purpose of writing this passage is   _  .
to call on more people to buy the new car to tell us something about the artificial intelligence to introduce the new invention of Google to describe the development of the Internet