Ask yourself , " Would I get in a car with no human driver if it pulled up right now? "
There's testing for these vehicles now and in California manufacturers/testers of driverless vehicles asked for and received permission to make these vehicles without conventional steering wheels and pedal controls. Just a dash and a seat.
Hacking is a real threat. If cell phones , TV's , computers , email , anything electronic and connected to the internet have and can be hacked - what do you think will happen to a set of doubles pulling hazmat at 2am south of Chicago?
And like it was mentioned above , a proof of concept would be trains. It would be a LOT less challenging to automate trains on so many levels , yet there's little talk of this happening anytime soon. I will say I have used automated trains at major airports though.