It is no defense to say that Uber also told a human driver to be present. If Uber had directed a five year old to drive the SUV, with a back-up driver ready to take control, I think everyone would agree that qualifies as gross negligence notwithstanding the presence of the back-up driver. (To be clear, I think some risk in the name of progress is acceptable. But it's one thing to use testing on public roads to work out the kinks in the software. It's another to put vehicles on the road that you know cannot perform the basic, essential functions of driving.)
[1] http://www.latimes.com/business/autos/la-fi-uber-arizona-nts... ("However, Uber also disabled its own emergency braking function whenever the test car was under driverless computer control, 'to reduce potential for erratic behavior.'").