I’m zipping down the freeway at 70 miles per hour in a Mercedes-Benz S-Class and my hands aren’t on the steering wheel.

The wheel jogs slightly to the left, then returns to centre, moving eerily on its own. The executive-class sedan is driving itself—gas, brake and steering.

I’m trusting the digital ghost in this machine to keep us from plowing into the left-hand guardrail. I always figured the day of self-driving cars would arrive; just not so soon.

A soft warning chime. The car will self steer for only ten seconds without a hand on the tiller. After that you get another warning beep and the wheel goes slack. You—or the car—are on your own.

That’s okay, I’m happy to take back control.

Mercedes’s S-Class has always been a technological powerhouse, the repository of the company’s most radical advances and forward-thinking ideas. The results can’t be denied.

They include truly significant safety advances like crumple zones in the 1950s and electronic stability control 40 years later; advances that have filtered down to every car on the market. It’s possible someone you know has had their life saved by a car that they didn’t even buy.

The all-new, 2014 S550 rear- and all-wheel-drive models will be released this fall, with prices likely to start just south of $100,000. (I estimate the car I tested with all the gizmos was more than $140,000.)

Stutter step

While the sedan takes a stutter step towards autonomous driving, neither legislation nor the technology is at the point where an owner can crawl into the back seat and let the car whisk you to work. But Mercedes is telling us the day is coming.

There are loads of other advances and gadgets you can load on to this classic big black luxury sedan aimed at power brokers, CEOs and diplomats.

Some options are silly. You expect luxury and comfort in terms of leather, wood and superb temperature control (yes on all counts). But do you need the $350 package which places a perfume container in the glove box, atomizing the liquid at random intervals and wafting in Mercedes’s scents like Sport, Nightlife and Downtown?

Perhaps they should call it the covering up an illicit affair package, masking mysterious colognes or perfumes on one’s collar.

The seats include a massaging feature that is supposed to replicate a hot-stone treatment. Sounds odd, but it feels very, very good.

Safety strides

The biggest practical strides are those of safety. The car is surrounded by fields of invisible radar and festooned with cameras. It knows when other cars are crossing in front of you at an intersection, entering a blind spot or even likely to rear-end you.

In the last scenario, before a rear impact it will tighten your seat belts and automatically lock the brakes, so you’re less likely to plow into the car in front of you.

By contrast, the semi-self-driving features are destined to be used by drivers who text or e-mail in traffic. (Everyone agrees that is a no-no, yet I see people doing it all the time.)

The S550’s latest cruise control follows the flow of highway traffic, slowing or speeding up in relation to the car in front of you. Your feet stay off brake and gas. The steering assist helps keep centred in the lane, tugging gently when your hand is on the wheel. It also keeps you from veering into oncoming traffic.

Stop signs

Which means you can pay less attention, but you still need to be aware. If there are no lane markings on the road, the S550 will simply follow the car in front of you.

Fine, as long as that driver isn’t sending e-mails himself. And while the Mercedes halts for stopped vehicles in your lane, it doesn’t recognize red traffic lights or stop signs.

This brings another question into focus: Do owners want to drive this car or to be driven? Optioned correctly, rear seats recline and have nifty folding tables ideal for laptops.

An especially trick optional suspension ($4,450) uses twin cameras to read the road ahead and adjust wheel travel accordingly. You can literally roll over a speed bump and not spill your coffee in the back.

Bringing us, finally, to the drive itself. Because in truth, actual driving seems to be the last thing on anyone’s mind. The car has more CPUs than NORAD in the 1980s, so it perhaps come as little surprise that the experience feels synthetic and distant.

The 4.6-liter V-8 puts out a load of power (455 horsepower and 516 pound-feet of torque), and yet that potency gets lost in translation. The gas pedal is spongy, the steering drowsy. The S550 is a bore to drive.

Ultimately the place you want to be is the passenger-side rear, drowsing or sending e-mails. Let’s just hope that your chauffeur isn’t doing the same thing up front.

The 2014 Mercedes-Benz S550 at a glance

Engine: 4.6-liter V-8 with 455 horsepower and 516 pound-

feet of torque.

Transmission: Seven-speed automatic.

Speed: 0 to 60 mph in 4.8 seconds.

Gas mileage per gallon: 17 city, 27 highway (estimated).

Price as tested: $145,000 (estimated).

Best feature: Passive safety systems.

Worst feature: Synthetic driving experience.

Target buyer: The rear-seat CEO who doesn’t entirely trust

his driver. BLOOMBERG

Jason H. Harper writes about autos for Muse, the arts and leisure section of Bloomberg News. The opinions expressed are his own.

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