The minute you can make a truly driverless vehicle is the day you can pretty much replace every human with a robot.
I saw a video of these buses when it was announced and they still needed a "safety" driver behind the wheel.
Untill they can invent an Ai that can see and think like a human then it will never replace a human as the sensors/radar way of doing it at the moment falls flat on its face with weather, longer distances etc or unfamiliar territory due to needing to learn it's surroundings.