Self-driving cars could be on U.S. roads by 2020

DETROIT — Cars that drive themselves could be on U.S. roads by the end of this decade. But don't take your foot off the pedal just yet.

Automakers, universities and others are at various stages in the development of autonomous cars. Google is testing some in California. General Motors recently announced that its "Super Cruise" system, which uses radar and cameras to steer and stop a car, could be on Cadillacs by the end of this decade. And Nissan has boldly promised that it will have an autonomous driving system by 2020.

But there are still a host of issues to work through. State laws requiring a licensed driver at the wheel will have to change. Insurers will have to determine who's at fault if a self-driving car crashes. Highways will need to accommodate cars with and without drivers. And auto companies will need to ensure that cars' on-board computers can't be hacked.

In a recent report, consulting company Navigant Research estimated it will be at least 2035 before a majority of vehicles sold worldwide will be able to drive themselves. Navigant predicts that technology will come in bits and pieces, and will take some time to migrate from luxury cars to more mainstream brands.

Autonomous cars are moving from pipe dream to reality thanks to rapid advances in technology. Lane-departure warning systems, for example, first appeared a decade ago. Newer systems have multiple cameras and radars that can detect pedestrians and avoid them by telling the car to apply the brakes. Some cameras can even read street signs. And some lane-departure systems not only warn the driver with a beep or a buzz, but also gently nudge the steering wheel to make sure the car stays in the middle of its lane.

But technology isn't perfect. Amnon Shashua, the co-founder of Mobileye, a Dutch company that writes software for automotive cameras, says there are still some situations in which humans outperform computers.

Even as the research and development continues, some autonomous cars are already being tested. Last year, British auto supplier and engineering firm Ricardo successfully led an autonomous vehicle demonstration near Barcelona, Spain. One vehicle led four others — three Volvo cars and a truck — that drove themselves for more than 120 miles. The cars stayed 20 feet from each other and traveled at 53 miles per hour.

Despite all the uncertainties surrounding autonomous cars, many agree on their benefits. David Strickland, head of the National Highway Traffic Safety Administration, says self-driving cars could potentially save thousands of lives, since human error is currently a factor in as many as 90 percent of traffic deaths.