Smart luxury elevates common sense above extravagance.

It is costly, unaffordable for most of us, which defines it as luxurious.

But it sets standards desirable for many of us, especially in automobile safety. Consider, for example, the adaptive braking technology in this week’s subject vehicle, the 2013 Mercedes-Benz S550 4Matic sedan.

The all-wheel-drive car’s brakes are as impressive as its 429-horsepower, twin-turbocharged V-8, direct-injection gasoline engine. One moves you quickly. The other stops you with assurance. Peace of mind often is a matter of balancing equations.

The adaptive braking system blends a suite of safety technologies into several useful functions:

Predictive braking helps to provide immediate stopping power in emergencies. When you quickly remove your feet from the accelerator pedal, the brake pads automatically move toward the brake discs, preparing for a quicker stopping response when you actually apply the brakes.

Automatic brake drying periodically applies enough brake pressure to clear water build-up from brakes in inclement weather.

Hill-start assistance prevents unwanted rollback when the S550 4Matic, a car with a curb weight of 4,861 pounds (factory poundage minus passengers and cargo), is stopped on a steep incline. Gravity becomes a potentially dangerous enemy in such a circumstance. Hill-start assistance helps even the odds.

There is so much here, including torque-vectoring brake technology. Think of it as a system that applies the right amount of braking pressure to the correct wheel at exactly the right time in a turning maneuver to help keep the car on the line of travel, or vector, best suited to the turn.

It is wizardry fascinating to behold in performance. It is not infallible. Human frailty can undermine any system.

Consider the S550 4Matic’s “attention assist” system. It is engineered to monitor driving behavior — jerky turns, lane drifting, that sort of thing — and automatically alert the driver with visual and audible cues if it detects driver drowsiness on long trips. But there is only so much it can or will do to get your attention. It will not stop the car and serve you a cup of coffee. It will not move ambient traffic or potential crash objects out of your way. The fix is simple: If you are too tired to drive, park and rest.

There is also what Mercedes-Benz calls “distronic plus.” It is a radar-based cruise that monitors the distance and speed of a vehicle ahead of you and helps you maintain a chosen distance, or even bring your car to a halt if it senses stopped traffic. Driving resumes when traffic movement resumes.

I am aware that much of this runs counter to what many of us who love driving regard as driving. Many of us are control freaks, often with inflated self-assessments of our driving skills. We believe we can handle anything on the road and long for the opportunity to demonstrate as much. Automated, well-tufted fortresses such as the big S550 4Matic aren’t exactly the kinds of cars we think about when we think about zoom.

But there is so much good stuff here that demands attention. The S550 4Matic, of course, has legendary Mercedes-Benz S-Class comfort, craftsmanship and materials quality. There is supple leather superbly stitched. There is real burl walnut wood trim. There is more than enough here to make you feel rich, even if you aren’t.

But its resonance with me was the safety of it all, the motorized version of an all-inclusive, practically everything covered health insurance policy. All of us should have access to the safety technology in this automobile. But we should not have to pay $120,000, the full price of the subject vehicle plus options, to get it.