Sonoma, California - What Audi calls piloted driving - cars that drive themselves - is rapidly getting closer to the real world.

And in this case, 'rapidly' means lapping the challenging 4.05 kilometre Sonoma Raceway - better known by its former name, Sears Point - at race pace, lap after lap, without a driver on board.

The car in these pictures is Robby, an updated version of the autonomous RS7 that blitzed the Hockenheimring in October 2014 in front of a race day crowd at speeds of up to 240km/h. Robby is about 400kg lighter than its predecessor and has 412kW on tap - never mind who's driving, this is one quick car.

Thomas Muller, Audi's top boffin for brakes, steering and driver aids, said: "We took the RS7 piloted driving concept to its physical limits at Sonoma, and it posted lap times better than those of sports-car drivers."

How quick? Robby's 'personal best' was a potentially race-winning 2m01.01s - and it could get very close to that, every lap, until the tyres gave out.

And the two RS7s are by no means the first: in September 2010 a driverless TTS called Shelley ran the 19.8 kilometre Pikes Peak hill-climb course in 27 minutes.

Audi is already moving that technology on to real-world roads. Early this year an Audi A7 called Jack, fitted with a number of near-production systems, drove itself from Silicon Valley to the Consumer Electronics Show in Las Vegas.

No long afterwards, it coped with traffic on a German autobahn at speeds of up to 130km/h and in May, it gave journalists covering CES Asia a taste of piloted driving on the busy streets of Shanghai.

The technology works - that's no longer in dispute. Audi is now developing series-production systems, refining its sensor and data processing capabilities, and teaching it the niceties of car control and stabilisation.

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Muller points out that piloted driving is about safety, saving time, efficient driving and, of course, convenience, as it gives drivers more freedom to do their own thing while the car deals with the daily commute.

And it's just around the corner; the next-generation A8, due to debut in 2017, will be able to park itself and drive itself on in stop-go traffic on freeways at up to 60km/h.

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