Using artificial-intelligence, Internet giant Google is secretly developing a car that can drive itself, a development experts say could transform society as profoundly as the World Wide Web has.

Seven test cars of Google have driven 1,000 miles without human intervention and more than 140,000 miles with only occasional human control, New York Times reported.

The car project of Google uses artificial-intelligence software that can sense anything near the car and mimic the decisions made by a human driver.

The device a top the car produced a detailed map of the environment which was used to navigate safely.

One test car drove itself down Lombard Street in San Francisco, one of the steepest and curviest streets in the US.

The only accident, engineers said, was when one Google car was rear-ended while 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, sleepy or intoxicated, the engineers argue.

They 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.

The car can be programmed for different driving personalities ? from cautious, in which it is more likely to yield to another car, to aggressive, where it is more likely to go first.

The project is the brainchild of Sebastian Thrun, the 43 -year-old director of the Stanford Artificial Intelligence Laboratory, a Google engineer and the co-inventor of the Street View mapping service.

Besides the team of 15 engineers working on the current project, Google hired more than a dozen people, each with a spotless driving record, to sit in the driver's seat, paying USD 15 an hour or more. Google is using six Priuses and an Audi TT in the project.

The Google researchers said the company did not yet have a clear plan to create a business from the experiments.