Other automakers, such as Nissan Motor Co. and Honda Motor Co., have systems coming that will give drivers 30 seconds to prepare to re-engage and that can pull to the side of the road if the car doesn’t detect human hands on the wheel.

“You can even go to sleep and the car can wake you up,” said Amnon Shashua, co-founder and chief technical officer of autonomy supplier Mobileye NV, which is providing Level 3 systems to Audi, BMW, Honda and others. “You know, waking up for 30 seconds is quite a long time.”

That’s not how Hakan Samuelsson sees it. A person at rest or distracted by e-mail or entertainment can’t be expected to quickly take the wheel and save the day, according to the Volvo Cars CEO. No sensor exists yet that can predict far enough into the future to give a driver enough time to prepare to avoid a crash, he said.

“We don’t believe in five seconds, 10 seconds,” Samuelsson said. “It could even be dangerous. If you are doing something else, research shows that it will take two minutes or more before you can come back and take over. And that’s absolutely impossible. That really rules out Level 3.”

Manual Operation for Pleasure

Volvo, siding with Ford and Waymo, will deploy a self-driving system in 2020 that won’t require human intervention. It’s now being tested as a robot taxi by Uber Technologies Inc. Volvo will outfit its self-driving XC90 sport utility vehicle with a steering wheel that tucks away while in autonomous mode, but also allows its owner to drive manually for pleasure.

“A premium car is one you can use as an office in the morning and then drive it yourself on a nice country road in the evening,” Samuelsson said. “You will never end up in no-man’s land.”

Legal liability could be driving most automakers to put the wheel in the driver’s hands in an emergency, said Joe Vitale, global automotive leader for consultant Deloitte.

“With a vehicle crash when it’s operating in Level 3, I’m sure manufacturers will believe the consumer is responsible because they have their hands on the wheel and they’ve been alerted,” Vitale said. “But I don’t think regulators are going to easily turn over on that issue.”

Confusion Around Legal Liability

Volvo has pledged it will accept responsibility for any crashes by its self-driving vehicles. Samuelsson said Level 3 could create confusion over who is legally liable for a crash.

“It should be black and white,” Samuelsson said. “With responsibility, you cannot tell anybody you are a bit responsible. Either you are responsible or you are not.”

One matter both sides agree on is that too many requests for human intervention could wreck the autonomous experience.

As part of its testing, Ford used sensors that monitor facial expression and track eye movement to determine if a driver was alert and ready to take over. This led to an unenviable experience in which drivers felt they were being constantly reminded to pay attention. “The car is actually yelling at you all the time,” Nair said.

"Still Annoying"

Takeover requests from your car should be “quite rare,” Mobileye’s Shashua said. “If it’s every 10 minutes, even with the 30-second grace period, that’s still annoying.”

It also would undermine the value of having an automated chauffeur, according to Mark Fields, Ford’s CEO.

On Feb. 10, Ford announced a $1 billion investment over five years in Argo AI, a months-old startup founded by former leaders on the self-driving car teams at Uber and Google.

If Level 3 cars are constantly badgering the driver, Fields said, owners will wonder: “Why did I spend that extra premium for this if I have to be alert and pay attention?”

By Keith Naughton