How to give control back to hands-off drivers?

As industry engineers and designers contemplate the transition to more vehicle autonomy, they're looking especially hard at what happens in Level 3 automation, as defined by the U.S. Department of Transportation.

In the Level 3 scenario, the driver's hands could be completely off the steering wheel for extended periods. But drivers have the option of resuming control.

What happens to the steering wheel when it's not needed for driving? How does it return when the driver opts to retake control? And how fast should the entire transition happen? It's a complex issue, fraught with engineering and design challenges.

"Bringing the driver back in the loop in a safe way and acceptable time is a difficult task to solve and surely not only a steering wheel issue," said Manuel Poyant, senior manager, core engineering, steering wheel systems for ZF TRW.

"Challenges are diverse, not only technical but also ergonomic. Thinking of a situation where the driver's seat would be in a pushed back and in a semireclined position, would make it very difficult for the driver to be able to take control of the car in a short time."

That "will force OEMs and Tier 1s to rethink active- and passive-safety concepts," for example, positioning of the seat belt and the driver, says Poyant.

At the Consumer Electronics Show in Las Vegas in January, Rinspeed showed its Etos concept, equipped with a ZF TRW retractable steering wheel that is designed to enable the driver to move efficiently in and out of autonomous mode.

Says Richard Matsu, director of engineering for Autoliv Inc., the Swedish supplier: "If someone's in full autonomous mode and decides it's time to take over, how long does it take a person to take over?

"Then you compare that to the time involved in an accident or dramatic event on the roadway," Matsu said. "You really have to understand: "Can the person come back into control quickly enough?' The handoff becomes critical."

Automakers and suppliers are working on systems that will allow drivers to resume control as quickly as possible, while ensuring they're fully prepared to do so safely.

Mercedes-Benz says its Vision Tokyo concept is designed to anticipate several minutes in advance when the handover would take place. The vehicle signals the driver when to assume control of the wheel as the seat moves into "a classical driving position."

At CES this year, French supplier Valeo introduced a next-generation cockpit concept called Valeo Mobius. When the car is in autonomous mode, the system uses smartwatch-size touch screens on either side of the wheel that allow the driver to do various functions such as texting or reading email.

But when the vehicle is in manual mode, the buttons display only driving-related functions or standard operations such as changing radio stations. The steering wheel doesn't retract.

Amine Taleb, manager of advanced projects for Valeo comfort and driving assistance systems, says the "talk in industry is that you should be able to take back control within 10 seconds."

Jeremy Carlson, autonomous vehicle analyst for IHS Automotive, says 10 seconds is for the kind of "leisurely" transition from autonomous to manual control, such as when a driver is exiting a freeway into urban traffic, for example, but not an emergency situation that calls for slamming on the brakes.

It's that emergency reaction time that has some wondering.

Like others in the industry, Robin Page, Volvo's chief interior designer, isn't at all sure about whether this intermediate step involving retractable steering wheels will even happen. Accidents often take a fraction of a second to unfold; by the time a driver resumes control, it might be too late.

"If it's going to take a few seconds to come back, that's quite daunting -- maybe that's not attractive for a real-time customer," said Page.

"I think there are definitely two worlds -- where it is absolutely full autonomous, and a world where the steering wheel is what you need to drive. Do we need to do anything in between or not?"