A General Motors promotional film envisions the future: Drivers enter the highway, put their cars on "autopilot" and sit back as the vehicle takes over and heads for the horizon. The film's date? 1956.
Nearly 60 years later, automakers are making that dream a reality.
But the technology has sprinted ahead so fast that lawmakers and regulators are scrambling to catch up with features like hands-free driving that are now months away, rather than years.
This summer, Tesla, the maker of high-end electric cars, is promising to equip its Model S sedan to take over highway driving under certain conditions. In January, Audi will introduce a vehicle that can pilot itself through traffic jams. And next year, Cadillac will offer no-hands highway driving with its "Super Cruise."
Limited forms of hands-free driving have already arrived. Luxury brands such as Mercedes-Benz and Infiniti offer "lane keeping" features that allow drivers to take their hands off the wheel for periods of time on straight stretches of road.
But the innovations have prompted the question: Is it legal?
Few rules on the books
The vast majority of states do not have any rules at all. The few that do passed the laws primarily to allow research and testing. Only New York specifically requires that drivers keep one hand on the wheel, but that dates to a law from 1967.
As a result, automakers are pushing into a regulatory void.
"Where it's not expressly prohibited, we would argue it's allowed," said Anna Schneider, vice president for governmental relations at Volkswagen, which owns Audi.
"We don't need any change in legislation to put Super Cruise on the road," said Dan Flores, a spokesman for General Motors.
On a recent afternoon, a Volvo official demonstrated its new XC90 sport utility vehicle along a leafy road in New Jersey. Set for release in June, the XC90 has a semiautonomous feature called "pilot assist" intended for congested traffic.
After a driver pressed a button on the steering wheel, sensors scanned the road and locked on to the vehicle a few car lengths ahead. A white icon lit up on the dashboard, and the wheel began moving on its own.
As the road curved, the Volvo steered itself through it, automatically adjusting the throttle and steering. The vehicle seamlessly kept on going, though after about five seconds, a subtle dashboard light asked the driver to keep a gentle touch on the wheel.
Not that it was needed — the Volvo could keep going hands-free for miles at speeds up to 30 mph on a properly marked road. But for now, Volvo has programmed the XC90 to start slowing down if a driver does not heed the warning light, making the vehicle a bridge between "lane keeping" and the truly hands-free technology set to hit the market soon.
"This is about making the tedious parts of people's drives less stressful," said Jim Nichols, a Volvo spokesman. "We're not talking about a driver simply checking out and not paying attention."
Drivers may still face scrutiny
Car manufacturers see hands-free technology as the natural next step in driving — an evolution that has gone from cruise control to anti-lock brakes to electronic stability control. None of those innovations required permission from regulators.
And legal experts say the automakers' positions are most likely correct — that in the absence of specific laws against it, hands-free driving is legal.
"Most states don't expressly prohibit automated vehicles," said Bryant Walker Smith, a professor of law and engineering at the University of South Carolina.
But that does not necessarily mean drivers will not face scrutiny.
"It's not just what's on the books; it's what's enforced," Smith said. "If a police officer sees you driving down the road with no hands, he could determine that's reckless and still give you a ticket. Individual officers have a tremendous amount of discretion."
California, Nevada, Michigan, Florida and the District of Columbia legalized autonomous technology in certain circumstances — primarily to encourage testing. Several others are considering rules.
But for consumers, and local officials themselves, the fractured nature of what is allowed, and where, may create uncertainty.
No federal rules explicitly bar the practice. Part of why federal and state officials have struggled to define autonomous rules is that the issue cuts across traditional legal turf.
"The federal government largely regulates vehicle design, such as 'Does it meet crash safety standards?' " Smith said. The states are the ones that have regulated drivers and their behavior, he said. "Now the car is becoming the driver."