If Mercedes-Benz and Nissan are right, 2020 will be a watershed year for self-driving cars.

Both automakers have promised to bring computer-controlled cars to market this decade.

In an interview at the 2014 Detroit Auto Show, we asked Ludwig Willisch, CEO of BMW North America, if the 2020 mark seemed premature.

He declined to speculate about others' efforts, but said, "I don't see that happening for BMW."

Willisch did little cheerleading for cars that drive themselves: "We would not say that going from A to B automatically should be done by the car. It should be done by the driver. Otherwise the whole notion of being the 'ultimate driving machine' would go away."

It might be good for lesser brands, he added: "Maybe if you have some car, some brand that's not at all exciting to drive, it probably is okay if you're driven by the car. Because you're not losing anything."

The point is, if you buy a BMW, you'll want to drive it, not let some computer have all the fun. An exception would be driving in heavy traffic, when driving is boring and you might as well read the newspaper.

But that stance doesn't seem to match up with the show BMW put on at the Consumer Electronics Show (CES) earlier this month in Las Vegas. It presented a prototype M325i which didn't just drive itself around a track — it drifted. That's the coolest thing a self-driving car has done since Google's version took a blind guy to Taco Bell.

To find out where BMW really stands on this, we turned to Dave Buchko in product and technology communications. He explained there is in fact a happy middle ground.

"BMW does not make cars for people who don't like to drive," Buchko told us in an email. But it recognizes that boring or aggravating driving circumstances (long highway distances, heavy traffic) create a risk for a risky "lapse in attention."

The CES demonstration, "while fun, was not meant to suggest that the company’s aim is to build the self-drifting car but to demonstrate that in order for highly automated driving assistant systems to be viable," they have to be able to take over in intense conditions. Thus, the awesome shot of the car sliding sideways around a corner, fully in control.

 "We still think that whatever electronics you have in the car," Willisch said, "it should support the driver, not dominate the driver."

So you drive when you want to. The car can take over when things get boring or dangerous. For those who love being behind the wheel, but hate traffic and prefer not to crash when things get out of control, that's great news.