It’s shortly after 11 p.m. at the beginning of December. With perfect timing – it’s the start of meteorological winter – the low-pressure system dubbed “Katharina” has brought snow and frosty temperatures to South Germany. But whilst many people would rather not venture out in their cars, Anton Rosinger is looking forward to a nocturnal drive through snow and ice.

“There’s nothing nicer than being out on the Jura plateau when it’s full moon and there’s fresh snow on the ground”, says the Swabian as he steers his C-Class through hairpin bends. The 55 year-old has plenty of dream roads to choose from: as a test driver for Mercedes he gets to drive on testing grounds and tracks all over the world, and knows the frozen surfaces of Scandinavia like the back of his hand, as he does the vertical curves of Nardo in Italy, the Namibian desert and Death Valley, scorched by the Californian sun.

But now it’s time for testing in his home country: the new-generation C-Class has to prove its long-term qualities in what is known as in-camera testing in the Swabian Jura. “We do this to simulate the first year of a new vehicle with the customer”, Rosinger explains. “Working in two shifts, my colleagues and I cover around 1000 kilometres every day.” Within two weeks the thinly disguised near-series prototypes will have more than 10,000 kilometres on the clock. The circular route is precisely defined and is composed of around 65 percent rural roads, 30 percent motorway and five percent urban traffic. The torture track on the test site in Stuttgart-Untertürkheim is also used.

Today the trained car mechanic is on a night shift, and he has no idea what awaits him between 11 p.m. and 7 a.m. “The procedure might be a very routine one, but every test day is different.” Rosinger certainly has plenty of experience under his belt: he has been with Daimler for 32 years, 28 of which have been spent in endurance testing. The E-Class predecessor, the W 123, was the first car he tested when he took on this role. Since then there have been huge changes in automotive technology – “above all in the fields of electronics and assistance systems”.

So the C-Class holds a sedate Sunday drive in store for us, pleasantly air conditioned and with the sounds of the audio system as a backdrop? Hardly. “I usually leave the radio switched off, so that I don’t miss hearing any rattling or creaking noises”. Because the endurance testing is not just about rigidly eating up the kilometres – Anton Rosinger’s tasks also include having an ear for locating the noises that only occur on certain road surface conditions or at specific speeds. After all, ensuring that Mercedes models do not draw attention to themselves on account of inappropriate noise or unpleasant vibrations is all part of the brand’s premium standard.

But Rosinger does not sit back and wait to see if a problem will arise – he actively subjects the C-Class to the same stresses the customers will be inflicting on their car over the course of several months: he diligently presses buttons, operates switches and plays with the controls, as the test drivers have to work through an extensive testing schedule, which includes frequent use of the power windows and closing the doors, as well as ignoring the route suggested by the navigation system – in order to see how the software reacts to the disobedient driver. If he notices anything untoward, Rosinger records a short message on his dictating machine, and then at the end of his shift he notes down every detail on his laptop.

But he is still only halfway through his shift, and no sooner has he reached the motorway, than Rosinger takes a short break. He has already covered a good 150 kilometres on the narrow, steep and sometimes snow-covered lanes of the Swabian Jura. So far there have been no problems to report – only the marten and fox have put in brief appearances at the side of the road. Even the 11 percent gradient on which a tester colleague had got stuck in freshly fallen snow the previous night was no trouble for the C-Class Saloon. It turns out that Rosinger is a brilliant driver who is sensitive in his operation of the steering wheel, accelerator and brake, displaying foresight in his driving style: “As time goes by you develop a sixth sense for the way in which other car drivers react”, says the Mercedes employee, who has covered nearly three million kilometres in his testing career.

Even members of Germany’s elite anti-terror unit, the GSG9, have profited from Rosinger’s driving skills, as he has demonstrated to them in courses how to act at the wheel in dangerous situations. He also uses his leisure time to prove his mastery of machines: Rosinger is a successful participant in motorcycle dexterity tournaments. These involve the completion of tests in which the entrants have to try and drive faultlessly in a circle one-handed, for example.

It goes without saying that both hands remain firmly on the steering wheel in the C-Class. Safety has top priority; the test drivers have to undergo extensive training and adhere to a code of conduct, and Mercedes-Benz also insists on annual health checks.

Now we’re cruising on the main road to Stuttgart. There’s an increasing among of traffic about: the revellers on their way home to bed and the morning commuters going to work keep us company as night turns into day. “I like working shifts, as it gives me more free time”, explains family man Rosinger, who currently enjoys spending every spare minute he has with his 20 month-old granddaughter.

In Untertürkheim we meet up for the first time with colleagues who have already completed their series of tests on the torture tracks. Is being a test driver not a lonely job? “That suits me down to the ground”, Rosinger admits, grinning. “As there’s no-one to stick their oar in all the time.” It is indeed very difficult to imagine the Swabian in a desk job. When he first started at Mercedes-Benz he was in the motor racing department, where he worked on the Mercedes 450 SLC rally car under Erich Waxenberger, which was how he also came to meet Walter Röhrl.

It’s now shortly before 7 a.m., and we’re approaching the circular route’s starting point. To round off his shift Rosinger still has to see to the documentation. Any incidents of note: none. A perfectly normal night’s work draws to a close.

Source: Daimler AG