The cars around that car are still communicating. So the car next to it sees a drastic speed drop and tells everyone else.

Also say the cars regularly ping each other for updates, then one car that was in sight and is still in sight disappears doesn't respond, then it gets flagged as a possible hazard.

What if 2 cars fail to communicate and can't flag each other?

You'll have an accident. But we have accidents already. The question is, what failure rate will we tolerate from autonomous vehicles?

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.

You mean for the system to work every vehicle which might have to stop in the road will have to be upgraded? Doesn't seem feasible.