Self-driving != Driverless
Self-driving cars is largely a technology problem, and one that we have made great advances in the last 5-10 years. Driverless cars are a legal/social/political problem that we have barely started to look at yet. Self-driving is a driving tool, like cruise-control, but the human driver is still ultimately responsible for the vehicle. Driverless on the other hand places the responsibility for the vehicle, and it's occupants, onto the vehicle itself. Driverless implies that you should be able to use it while you yourself are not capable of operating a vehicle. That is a massive step, and it is something that has never been done before. All other forms of transportation, despite advanced automation, still defers to a human in the end. I would say that true driverless cars is still a significant amount of time away, despite our advances in self-driving tech.