Hockenheim, Germany - A lap of the Hockenheimring is only 4.574km - hardly a great distance in term of automotive progress. Yet on Sunday 19 October it represented a giant leap forward for autonomous driving - the first lap of a Grand Prix circuit at racing speed by a car with nobody on board.
And we're not talking about a private test run behind closed gates - this was during the lunch interval on the final day of the German Touring Car season finale, in front of tens of thousands of knowledgeable German fans. Now that's what we call putting your microchip where your mouth is.
Audi calls them 'piloted' cars, which to us sounds a bit too much like remote control, while Google prefers 'driverless' (as in 'horseless carriage'?) so we'll stick to autonomous, if you don't mind.
Be that as it may, Audi's unmanned RS7 concept went round in just a few seconds more than two minutes, stuck to the racing line like it was being coached by The Stig and never once looked like it was getting out of shape.
Audi board member for technical development, Professor Doctor Ulrich Hackenburg, said: "This outstanding performance showcases the skills of our development team in terms of piloted droving at Audi
"And it's derived from current production technology, which is very important for future development."
HOW'D THEY DO THAT?
The autonomous RS7 uses specially corrected GPS signals, transmitted via WiFi and backed up by a simultaneous high-frequency radio signal, to orientate itself on the circuit.
At the same time, 3D cameras in the car film the track and a computer program compares the images to a data set stored on board, in much the same way a top racing driver memorises the circuit.
That's what makes it possible to drive the perfect lap, on the fastest racing line all the way round.
Audi, in partnership with Stanford University and the Electronics Research Laboratory in California, has been getting cars to think for themselves for 10 years. These high-speed tests are crucial to the development of automatic avoidance functions in critical driving situations.
The results are already to be seen in production cars such as the latest A6 and A7, in the form of lane departure warning - and assistance - and adaptive cruise control, with idle stop and pre-sensing functions.