The motor vehicle was invented over 100 years ago and we're still learning, adapting, and legislating around that. As soon as a functioning form of the technology becomes affordable it will kick away and we will spend the next 100 years learning and adapting.
The choice the machine will be programmed to make will have no value judgements in it. If there are two objects in it's path it will be programmed to steer in the direction that gives it the best opportunity to stop. But we all know that accidents will be unavoidable. If you have cruise control engaged in your car now and plow into the back of a vehicle who is responsible? I think it follows on logically from there.
Of course its a different scenario if ALL the cars are autonomous. When the car 6 in front of you brakes all the cars behind can know about it at electronic speed.
Nearly every day i'll be travelling at 80km/h and some clown will pull in front of me from a side road, causing me to brake or change lane. If i crashed and i had it on camera to prove it, it would be their fault. But its much better not to crash.
Statistics are one thing but there is also a psychological barrier to accidents caused by technology.
I die in the accident. My wife thinks......
My husband died, he drank and drove, he was so silly, if only i hadn't let him.
My husband died, he was texting, if only he hadn't, i'll tell other people not to do that.
My husband died, his car couldn't tell there was a truck in front of him and it didn't even slow down.
etc
Even if the accident rate halves, there will still be a non-acceptance of accidents caused by system failure.
There are currently legal cases involving conventional cruise control systems where people have claimed it causes accidents.
FWIW , when cars are all autonomous they will become totally boring IMO, like a tram or a suburban train.