Driverless cars and the big conundrum

DETROIT -- Soon we'll be driving vehicles that can steer, accelerate and brake themselves on the highway without the motorist's intervention.

The technology isn't foolproof, however, so drivers must be ready to take over if the vehicle encounters an unexpected obstacle. But if a motorist is texting a spouse or -- heaven forbid -- taking a nap, he or she may be too distracted to do so.

Indeed, if autonomous driving is Megatrend No. 1 in the global industry, the matter of how to handle the human interface may be Conundrum No. 1. It was certainly a hot topic last week here as auto executives debated the technology of driverless cars during the annual SAE World Congress, an event that attracted thousands of engineers.

"This is one of the most challenging parts of the development," said Cadillac spokesman David Caldwell. "There are many schools of thought and many concepts being tried."

Automakers have devised different techniques to ensure that the motorist stays alert. Some, such as BMW, require drivers to keep their hands on the steering wheel. Others, such as General Motors, plan to use other techniques.

The stakes are huge. It might take just a few well-publicized accidents to convince motorists that self-driving cars can't be trusted. If so, billions of r&d dollars would go up in smoke.

German luxury brands have been early adopters. In 2013, BMW unveiled the i3 hybrid equipped with Traffic Jam Assistant, which allows the vehicle to accelerate, brake and steer at speeds up to 25 mph.

Every 1,600 feet or so, touch-sensitive sensors ensure that the motorist is keeping his or her hands on the wheel.

BMW subsequently introduced the feature in the X5 crossover, the 5-series sedan and the 2-series Active Tourer. And the sensor supplier, IEE SA of Luxembourg, was a finalist for a 2015 Automotive News PACE Award for its technology.

Mercedes-Benz also requires motorists to keep their hands on the wheel when the vehicle is in self-driving mode. But it's too soon to assume that this will become the industry standard.

Cadillac, for example, will not require hands on the wheel when it introduces Super Cruise in the CT6 sedan in 2017.

John Capp, GM's director of controls and active safety technology, declined to reveal how GM will monitor the driver. Nor did he explain how the vehicle will alert the motorist that it's time to take over.

But he did offer some hints. In 2013, GM introduced a driver's seat that would vibrate to warn that the motorist was backing into an obstacle. The seat can vibrate on the right or left, letting the driver know which way to look.

Car owners liked it. "We got lots of feedback, and it's been positive," Capp said last week.

The vibrating seat seems to work better than audible alarms, which annoy some motorists, Capp said. For automated highway cruising, he said, GM might consider a dual warning setup -- perhaps a flashing light on the windshield plus a vibrating seat -- to warn motorists of road obstacles.

Will the Cadillac CT6 employ that setup? Stay tuned.

To reduce the motorist's stress, Toyota Motor Corp. favors a "no surprises" approach to transfer control from computer to driver.

Toyota's goal is a system that would give the driver 5 to 10 seconds to react to road obstacles, said Hideki Hada, general manager of Toyota's Intelligent Vehicle Systems, during an industry conference here last September.

At the time, Toyota offered journalists a glimpse of its technology -- called Automated Highway Driving Assist -- by demonstrating a modified Camry equipped with radar, cameras and lidar.

The car steered, accelerated and braked within its own lane on Detroit highways. Inside the cabin, an infrared camera tracked the driver's eye movements while touch sensors determined whether the driver's hands were on the wheel.

While Toyota's prototype worked pretty well, the automaker has not indicated whether it will use the same setup in production vehicles. But during the SAE conference, a Toyota executive reiterated the company's determination to avoid abrupt transfers of control.

"We want the system to be robust enough that it can give the driver enough time to take control of the vehicle," said Derek Caveney, Toyota Technical Center's manager of Integrated Vehicle Systems. "There's a lot of effort going into the sensors and algorithms."

While Toyota, GM and other automakers are tight-lipped about their plans to monitor the driver, suppliers are betting on in-cabin cameras.

Suppliers favor infrared cameras because they can track the motorist's eyes whether it's day or night, and even if the driver is wearing sunglasses. The camera can determine whether the motorist is fatigued or distracted.

Now Denso Corp. is trying to take the next step: Create an algorithm that analyzes travel conditions -- which might include weather, vehicle speed, traffic density, etc. -- to estimate the driver's stress level.

A year ago, Denso formed a research consortium -- dubbed AHEAD, or Advanced Human Factors Evaluator for Automotive Distraction -- with Honda, Subaru, Jaguar Land Rover and the MIT AgeLab.

The group wants to learn how to measure the driver's alertness and attention. That would prove useful for the design of intuitive vehicle controls.

"The key situation will be motorists who are inexperienced and not accustomed to the vehicle," said Pat Bassett, vice president of North American research for Denso International America Inc. "We are looking for a measurement method -- a meter -- to track the driver's workload."

Bassett acknowledged an uncomfortable reality for the auto industry: It's all very well to design partially autonomous vehicles for tech-savvy professionals, but others will be driving those cars, too.

Can the car owner's mother drive it? How about the owner's teenage son? The auto industry will have to sort that out -- and soon.