It's cute, but is it for real? Google's self-driving prototypes have received lots of attention, but the real advances may be happening elsewhere. Image source: Google.

This article was updated on Aug. 12, 2015.

Google (GOOG 0.74%) (GOOGL 0.55%) has received a lot of attention for its experiments with cars that can drive themselves. After extensive experiments with heavily modified Toyota (TM 1.07%) Priuses, the company last year moved to the purpose-built prototype shown above.

Google's self-driving car is certainly cute, but the vehicle -- or anything like it -- is still years away from the mass market.

And while Google's experiments have won a lot of headlines, some global automakers have made big progress toward autonomous cars.

In fact, one recently made a giant leap forward -- with a car that you can actually buy, right now.

This is what a self-driving car really looks like
I should qualify that. The Mercedes-Benz S-Class is a car you can actually buy -- but with a starting price of $95,650, it's not a cheap one.

It's big, it's expensive, and it's the closest thing you can buy to a self-driving car today: The Mercedes-Benz S-Class. Image source: Mercedes.

The latest S-Class was new for the 2014 model year. It goes farther than any other production vehicle has to date in integrating the technologies that will be key to the self-driving cars of the (near) future.

Many luxury vehicles -- and an increasing number of not-so-luxury vehicles -- already offer safety and convenience systems that are products of the effort to build cars that can drive themselves. 

American car shoppers are becoming increasingly familiar with features such as "adaptive" cruise control, which uses radar to keep you at a set distance from the car in front of you on the highway, and systems that use radar and cameras to detect objects in your blind spots.

Mercedes has taken all of that technology one big step ahead with an integrated system it calls "Intelligent Drive." The name is no exaggeration: Under some conditions, the system will actually drive the car for you.

Under some conditions, this Mercedes can drive itself
The feature that had industry insiders buzzing when the latest S-Class was launched is Mercedes' Traffic Jam Assist system. In certain situations -- think stop-and-go driving on the highway at rush hour -- the car can accelerate, brake, and steer itself, up to speeds of 37 mph.

The driver still has to pay attention, and be ready to take over from the computers. But even though it's very limited, it's the first self-driving system that goes beyond cruise control.

The Mercedes-Benz S550's dashboard combines traditional high-end luxury-car touches with elaborate high-tech features. Image source: Mercedes-Benz.

Only Mercedes has this technology available today, though Tesla Motors (TSLA 12.06%) is rolling out software updates that are expected to give its cars some of the same functions later this year. Volkswagen Group's (VWAGY -1.13%) Audi A8 will get its own Traffic Jam Assistant next year. And General Motors(GM -0.04%) new Cadillac CT6 will be offered with GM's similar "Super Cruise" system next year.

The traffic jam assist feature is just one of a host of functions included in the Intelligent Drive system. There are also systems that watch your blind spots, help you brake in emergencies, stabilize the car in stiff crosswinds, and assist with parking in tight spaces. There's even a feature that scans for bumps in the road ahead and automatically adjusts the suspension's settings to soften the blow.

It's expensive technology now, but not for long
Some of those features are just high-tech luxury-car excess, of course. But that's how new high-tech features have always come to market in the auto business: They start out on high-end luxury cars like the S-Class, then move into the mass market as volumes grow and costs come down.

Many of the features of Intelligent Drive aren't all that far from those already available in mass-market cars such as Ford's Fusion. Even GM's tiny new-for-2016 Chevrolet Spark -- the brand's cheapest car -- has forward collision alert and highway lane-departure warning systems. It's a safe bet that most of the key features included in Intelligent Drive will make their way to the mass market over the next several years.

Truly self-driving cars still face big obstacles, starting with the need for regulation that takes them into account. But the effort Mercedes has already made to integrate these systems into a cohesive package that is simple for drivers to use and available right now is enormous, and impressive. 

Trade publication Automotive News quoted a source within Mercedes parent company Daimler (MBGA.F -0.04%) as saying that Intelligent Drive had been in the works for 15 years before it was released. 

It's certainly ahead of anything Google or anyone else is offering at the moment. But it's fair to say that Daimler's development effort is far from over -- and its biggest rivals probably aren't too far behind.