Right now, laws still require a driver to be "in control" of the vehicle, usually meaning someone in the driver's seat, ready to take control when needed. Even if you never needed to take active control of the vehicle, you would still be unable to if the situation did arise. The "in control" part is how you can be arrested for DUI even if you're in a stopped car while intoxicated.
In the future, when self-driving cars get to the point of not needing someone in the driver's seat, the law will likely still require someone to be "responsible" for the car. In other words, similar to now, someone that could take over control in an emergency and would be held responsible for the car's actions. As is said in the thought-provoking I, Robot movie, "...a robot cannot be charged with homicide.... murder can only be committed when one human kills another".
In the future, there may be new legislation to allow kids, people without license, empty and drunk people to in a self-driving car.