Will your first self-driving car be a Cadillac? General Motors hopes so, and is working hard on introducing "Super Cruise", their name for self-driving technology.
According to Cadillac, one of the main features still in development is the pivotal “lane centering” technology. When combined with the other pieces of the puzzle, this will allow the car to see the lines that make up driving lanes and ensure that the car stays centered while en route to it’s destination. Coupled with the GPS, the car with be able to be aware of the exact lay out of the road. The only exception is when the lines do not exist, or are not visible, in which case the driver will have to take the old-fashioned route and drive with both hands.
(Cadillac Super Cruise video)
"Super Cruise is designed to ease the driver's workload on the freeway, in both bumper-to-bumper traffic and on long road trips by relying on a fusion of radar, ultrasonic sensors, cameras and GPS map data."
Robert Heinlein thought your first self-driving car would be a Camden speedster; he wrote this explicit description of a car driving itself on a highway:
The car slid up the ramp, waited until the traffic control signaled a predicted break in traffic, then joined the high-speed northbound stream. Mary Risling settled back for a little nap...
She woke just before the signal from the car which would have called her... She signaled the traffic control ahead; it cut her out of the stream of vehicles and reduced the speed of her car, then rang the alarm which notified her to resume local control.
(Read more about Heinlein's self-driving car)