The big city can be a stressful place to drive; the best way forward is to choose a car that is the zenith of years of research into how to create the calmest possible driving environment

Like any great city, London is a challenging place to drive in. Can you cut across three lanes of traffic in time for that turning? Squeeze into that gap? Miss that pothole? Do all the above everyday without having a cardiac arrest?

My urban motoring strategy is simple: I live and work in central London and spend a lot of time (if not many miles) behind the wheel. It’s a hectic schedule, and I want a car that will a) decrease my stress levels; b) enhance my working capabilities (partly by doing a); and c) be enjoyable to drive properly, given the chance.

And that is why I have just taken possession of a Mercedes S-Class. It might seem counterintuitive to have a big car in London, but not to me. The obvious ways to decrease stress are found by nature in large cars, which tend to be quieter and smoother than small ones. And the S-Class works in far more subtle ways too, the result of 15 years’ extremely serious, Germanic research by Daimler, Mercedes’ parent company, into the preferred driving environment of wealthy business people.

So, I settle down into my car and onto a seat so utterly comfortable that it has the seal of approval of Germany’s ‘healthy back campaign’. It somehow manages to be soft and firm at the same time, like a great bed. Inside, the seals are so effective that there is sepulchral silence: even the noisy stereos of other cars don’t penetrate. Potholes and bumps in London’s roads disappear under a suspension that benefits from a topographically patterned floor panel designed specifically to counterbalance vibration. The screen displaying the sat-nav and the car’s settings is the climax of a decade of research into what the most restful colours are for a driver to look at. The result is an unprecedented sea of calm that washes over you in the car. When I sit in the car after a meeting, I emit a large involuntary sigh of relief, and downshift into a state of peace previously unknown in Mayfair.

Peace and silence is wonderful, but if the car is frustrating to drive, the whole effect is lost. And that’s where the other side of the coin comes into play. You want something agile in London traffic, and the S-Class’s steering has been developed to be both light and super-responsive, with a rapid reaction to a tiny input at the wheel. The three-litre, six-cylinder turbodiesel engine has been retuned for extra torque, the force that propels you into gaps in the traffic. A smart electronic system even brakes the car when a white van cuts in front of you. The result is a car that is very agile for its size, making driving easier still. And because it’s an efficient diesel, it doesn’t even gulp fuel: its latest reading is 26 mpg, which is remarkable for a luxury car.

Daimler, which takes these things extremely seriously, conducted 35,000 kilometres of tests on the car’s effect on drivers, hooking them up to physiological monitoring machines while they plied busy routes in Germany in the S-Class and its two biggest rivals. The result? A driver’s heartbeat, a direct measure of stress, is up to six per cent lower in the S-Class than its rivals; the biggest difference is in the city. Given the amount of importance placed by executives on reducing stress levels, it’s a remarkable result, and one I can back through my subjective experience. Now all I need is for Daimler to get started on my office and home… – Darius Sanai

Mercedes-Benz S 320 CDI; www.mercedes.com