Volvo

There are no fully self-driving cars on sale today. Any vehicle with a semi-autonomous system -- whether Cadillac Super Cruise, Tesla Autopilot or something else -- requires the driver to pay attention and take over at a moment's notice. But by 2021, Volvo hopes it'll have a car so advanced that a driver could nap behind the wheel while the car drives itself.

Speaking at the launch of the S60 sedan yesterday, Volvo Senior Vice President Henrik Green told The Car Connection that the next-generation XC90 SUV would offer Level 4 self-driving technology by 2021. The goal is for the system to allow for "sleeping passengers" when driving on certain limited-access highways.

The Society of Automotive Engineers defines Level 4 automation as a car that can handle all driving operations in certain situations, without requiring a human fallback if something goes wrong. Volvo has been testing cars with autonomous technology likes this around the world, including in partnership with ride-hailing company Uber. And it even let two Swedish families borrow self-driving XC90 prototypes. But so far, no automaker sells a Level 4 autonomous system to the public.

Green told The Car Connection that the autonomous system would be called Highway Assist and would be a "four figure" paid option on the next XC90, which will be built alongside the S60 at Volvo's new plant in South Carolina. Volvo said it would work with regulators to make sure the Highway Assist system was legal. So far, even Level 3 autonomous systems -- namely Audi's Traffic Jam Pilot -- have met legislative resistance here.