Fatal Telsa crash shows limits of self-driving technology

Right now, those vehicles always have a steering wheel, brakes and a driver ready to take over in case of a problem, but prototype cars without steering wheels are also being developed.

A network of cameras, radars and lasers feeds information to the car's computers, helping to fill in the gaps in the GPS system, which knows how to get the car from point to point.

Later this summer, the federal government is expected to release guidelines for the safe deployment of autonomous vehicles.

Intel CEO Brian Krzanich said Friday that 90 percent of car accidents are caused by human error, and distracted or drowsy driving accounts for some 13 percent of those crashes.

A few automakers offer cars and SUVs with semi-autonomous modes that can perform some functions without help from the driver, including maintaining a set speed, braking, changing lanes and even parallel parking.

Semi-autonomous features can be found on high-end vehicles from Tesla, Mercedes-Benz, Infiniti and Volvo.

Toyota, for example, plans to make automatic emergency braking standard on its vehicles by 2017, ahead of a self-imposed deadline of 2022 that most automakers have agreed to.

IHS Automotive, a consulting firm, predicts that the U.S. will see the earliest deployment of autonomous vehicles, with several thousand on the road by 2020.

Driverless cars need detailed maps to follow, and companies are still mapping roads.

Tesla CEO Elon Musk said the car's radar is also designed to tune out what looks like overhead signs to prevent false braking.

Raj Rajkumar, a computer engineering professor at Carnegie Mellon University who leads its autonomous vehicle research, said computers can't be programmed to handle every situation.

Tesla would not comment directly on the radar and computer programs, but the company issued a statement saying that it continually advances its software by analyzing hundreds of millions of miles of driving data.