The idea of self-driving cars is a tantalizing promise. Get in the car, tell it where to go, and kick back. Already, YouTube videos show people sitting back and letting Google, Mercedes-Benz, and Tesla cars drive themselves.

But Volkswagen’s top autonomous-driving executive warns about rolling out the technology too quickly—even as the company hires a self-driving car expert from Apple.

Although big steps have been made in areas such as intelligent cruise control, and pre-collision warning and automatic braking, those advances are still a long way from a properly working autonomous vehicle in a larger traffic system, said Thomas Form, VW’s head of electronics & vehicle research.

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“An automatic driving car will not take the role of the driver. (It) can be overwhelmed by a situation, whereas I, as a driver, would never fail in this situation,” Form said in a speech at the Connected Car Expo at the 2015 LA Auto Show. “There will be accidents with automatic driving cars. We must (decide) what kind of driving skills they will be allowed to have.

Volkswagen Golf GTE Sport Concept eveals a future vision for a high-performance plug-in hybrid. Where do self-driving cars fit into the picture?
Volkswagen's Golf GTE Sport Concept reveals a future vision for a high-performance plug-in hybrid.

Form noted several complicated obstacles that autonomous vehicle systems still must overcome:

  • Today’s autonomous systems often fail in inclement weather, dim light, or nighttime.
  • The system logic may become confused by a situation, such as a policeman telling a driver to run a red light or stop at a green light.
  • Although self-driving cars can identify other cars, how would an autonomous car react to a tumbleweed in the road? Would it run over a rabbit but stop for a hog? Would it know that a truck with a wide load extending into the adjacent lane should not be passed?
  • Road signs, street markings, and traffic signal locations are different in various U.S. states, let alone between different countries, making the software programming for self-driving cars that much more challenging.
  • If the car recognizes a difficult situation ahead that requires the driver to intercede, the driver may not be ready to take over the car. 
Google Self-Driving Car
Google Self-Driving Car

“Either the car is capable to drive by itself, or the car must know well in advance—at least 10 seconds—to give the car control back to the driver,” Form said.

Form said that there have been some “convincing” demonstrations of intelligent driving technology—such as automotive supplier Delphi taking a self-driving car across the United States, and VW subsidiary Audi racing a TTS around Thunderhill Raceway in California faster than a skilled human driver—but “the real world is 24-7.”

“There are so many tiny problems that we must solve,” Form said in an interview following the speech.

When asked what an autonomous car should do if faced with a Catch-22 accident situation—where someone will be hurt or killed no matter what action the autonomous car takes—Form took the question out of the realm of the ethical and into the pragmatic.

“If the collision is unavoidable, the car should aim for the farthest ‘target,’ and brake as much as possible,” Form said.

But what if the farthest target is a bus filled with children, and a nearer target might be a solitary driver?

Said Form: “Giving a car decision algorithms leads to disaster.”