This is really hard to tell...will they even save lives at all? Is technology that reliable?
One thing is for certain, these cars will not work in many countries...especially in countries with too much traffic, such as India, Brazil...
Price will be high, technology will have to be perfect...in fact these cars already made victims in the USA. I personally love technology but I do not trust this kind of thing, as we know that technology fails...and one failure can cost lives.
Maybe it will spare a few lives in the long run, (decades from today) when the technology used is top notch...but until then I do not think I trust these, especially in crowded areas.