SAFE: The new M-Class has all the safety mod cons, even at the bottom of the range. Picture: QUICPIC

YOU probably haven't heard of Nils Bohlin, but if you've ever had a serious accident, he probably saved your life. After an early career designing ejector seats for aircraft manufacturer Saab, he went on to invent the three-point seatbelt, which he presented to Volvo in 1959. The Volvo Amazon was the first car to have them as standard.

In a modern car, the driver and passengers are protected by an array of safety systems. I spent a few days in Jo burg last week and drove a new Mercedes B-Class during my stay. This is not a top-of-the-range car, and yet the steering wheel vibrates when its sensors see I may be drifting out of my lane, and it flashes a red light when it thinks I am too close to the car in front. And if it thinks I haven't seen a car braking in front of me, it sets off a loud alarm. None of these things are perfect. I did spend a lot of time shouting at the car, "I know, I know!", as a car designed for Germany's disciplined motorways had electronic hissy fits. And, of course, top-of-the-range cars have airbags for your knees and stability control and crumple zones and so on. Modern Mercedes-Benzes keep a watchful eye on your driving style and suggest a cup of coffee if they think you're driving like you're a bit tired. But it's the seatbelt, as invented by Bohlin, that really saves lives.

The US National Highway Traffic Safety Administration reckons seatbelts save 11000 lives a year in the US alone. In 2009, the 50th anniversary of the three-point seatbelt was marked by Volvo's announcement that by its reckoning, Bohlin's invention had saved more than 1-million lives. And while Volvo continued to innovate for automotive safety, Bosch invented electronic stability control, which first appeared on the Mercedes S-Class, and it was Mercedes again that introduced, in 1998, what it calls Disctronic, or adaptive cruise control, which uses radar to adapt its speed to that of a slower car.

Perhaps it is because of this clever stuff that some people think they don't need to wear seatbelts. But, as the numbers show, not only should you be clicked in, so should your children. Nothing makes my blood boil more than seeing people holding children on their laps or letting them rampage about on the back seat. Can people seriously think the back seat of the car is in any way less involved in a crash than the front seats?

As a committed libertarian, I oppose laws that force adults to wear seatbelts. If they want to die by being decapitated by their airbag, then so be it. A very informal survey of the Joburg traffic suggested that 20% of drivers don't wear a seatbelt, and the police never seem to, so it's not as if they're worried about it either.

But children? To channel a certain TV personality, people who do not strap in their children should be shot. If you can afford the car, you can certainly afford the car seat.

Mercedes-Benz recently released what might arguably be one of the finest family cars I have driven in a long time. The ML250 Bluetec. The all-new M-Class is a bit of a leviathan to be honest, almost as large as the gigantic GL. But its size is just one thing. For the first time doing this job, I got the impression driving this car that Mercedes might be back to building as beautifully over-engineered cars as it did in the 1980s. There is not a single fitting or element of the interior of the ML that does not feel bomb-proof and of top quality. And while it's pretty scandalous for a Mercedes executive to claim that the firm invented the luxury SUV in 1997 (1970's Range Rover and 1989's Land Rover Discovery might find the idea a bit much), it certainly has moved it forward in this car.

On the road, the new ML is incredibly refined and quiet - noticeably better than anything that might compete with it. It also rides very well and corners just fine for a big old barge. You can order your ML with self-levelling hydraulic suspension if you like, but to be honest the steel springs felt just fine to me.

In fact, the ML is such a quality product that it bodes extremely well for the next-generation S-Class, which, if this is anything to go by, will have Rolls-Royce-worrying levels of sophistication and refinement. I'd plump for the entry-level 250 Bluetec, which has a 2,1l diesel motor and returns an astonishing official combined consumption number of 6,3l/100km. On our quick test, we averaged 8,3. In a car that weighs 2,2-tons, that's between clever and voodoo.

A small motor in a big car means the ML250 is pedestrian, but not dangerously so. They've still squeezed 500Nm of oomph out of that motor, giving it a towing capacity of no less than 3,5 tons. All of this costs no less than R683900, for this, the bottom of the range. It's enormously expensive. But it is excellent.

And, of course, it has the safety kit in droves, so you can expect the drowsiness detection system, Attention Assist, the "anticipatory safety system", Pre-Safe, BAS, Active Lane Keeping Assist, Blind Spot Assist, nine airbags and on and on it goes.

It also comes with seatbelts to Bohlin's design. And you should wear them.

.Parker is deputy editor of Top Gear Magazine SA.