I wish I could give you an actual solid answer but I'm not a lawyer. My suspicion is that if Boeing could kill 346 people with their 737 MAX negligence without anyone going to jail, then

• The people responsible for the self driving car software
• The people in Waymo who collate the evidence for why it can go on-road
• The legislators reviewing that evidence and approving it

Would have little to no legal consequences except if there is a very obvious negligence, like what happened to Uber. In this case this resulted in,

• negligent homicide for the person legally driving
• suspension of autonomous vehicle testing which led to shuttering the whole division

But it's a different one as there was a driver "monitoring" the system. I don't know how it would pan out in a driverless case to be honest.