It should be Zero. Computers don't make mistakes is the entire reason anyone would even consider letting an automated car pickup their kids.

I disagree and I have a kid. I'd be happy to let an automated car pick up my kid if it was demonstrated to be safer than I'd likely be.

Car related deaths are fairly common, I can't see any rational reason to not switch to autonomous driving as soon as they are statistically likely to save lives.

Do you really want a large (35,000 a year or so in the USA) people to die every year until autonomous cars are perfect? Not to mention nothing is ever perfect.

It's a trust issue.

Doing your best and working towards safety is one thing. Putting 100% trust to autonomous thing is a different thing. If you know it's 100% safe, than it's rather easy to do. But if it's 98% safe.. It's pretty much gambling. You know it may fail and you have no chance to influence it. Sit back and hope you're not the (un)lucky one.