The technology to enable self-driving vehicles is maturing faster and faster these days. Google, Delphi, and others are testing their autonomous cars on the streets of California and elsewhere, taking journalists for rides and even getting into the occasional fender-bender. Audi is one of the car makers leading the charge for autonomous vehicles, and it's been demoing its technology on the racetrack. Last year the company showed off a self-driving RS7 called "Bobby" at the season finale of the German equivalent of NASCAR. Today, the company announced that Bobby's smarter, lighter sibling "Robby" has been taking to the track here in the US, and he's faster than ever.

Robby has been putting Audi's autonomous driving tech to the test at Sonoma Raceway in California, 90 minutes north of Silicon Valley. The new car is 882lbs (400kg) lighter than its predecessor, and even with the sensors and processors it's only now approaching the weight of the production RS7. Audi says it isn't just teaching the car to lap for publicity though, the point is to make sure that a self-driving car is capable of exploiting the entire performance envelope of the vehicle.

"In Sonoma we brought the Audi RS7 piloted driving concept lap after lap to the physical limit, and in constant precision. The car reached lap times that were better than those of some experienced sport riders," said Thomas Müller, Head of Development for Braking, Steering, and Driver Assistance Systems at Audi. The company put some politicians, including California's Lt. Governor, in the passenger seat for the demo. This was probably a smart move, as getting regulatory approval (along with insurers and customers) is going to be more of an impediment to autonomous cars than the silicon side of things.

The next generation Audi A8 will be the first car from the company with the ability to drive itself out of the showroom, assuming the policy problems are solved by then.