Released last month, new Tesla software includes (the NYT reports)
a semiautonomous feature that allows hands-free, pedal-free driving on the highway under certain conditions. The car will even change lanes autonomously at the driver’s request (by hitting the turn signal) and uses sensors to scan the road in all directions and adjust the throttle, steering and brakes.
It is the first time that a production vehicle available to consumers will have such advanced self-driving capabilities. Or more to the point, the first time they will be unleashed for driving 70 miles per hour along twisty, though clearly marked, highways for long stretches. (Other manufacturers like Volvo and Mercedes-Benz recently introduced their own semiautonomous features, but limit the functions to lower speeds or require the driver to constantly touch the wheel.) And it’s perfectly legal. Among the states, only New York has any law prohibiting hands-free driving.
Check out the NYT's account of driving an autonomous vehicle.