Here in Central Oregon we are currently suffering from "black" ice on some of the roads. I suspect these self driving things would kill you in these conditions. In packed snow, you have to start braking very early and very gently. You then pick your spot on where to stop based on road surface conditions and slope. Are these smart cars that smart? I doubt it.
There are many other situations were experience and common sense are way beyond the capabilities of self driving cars. For example, there are times when it is best to illegally cross a double line (kids, livestock, people on horseback, joggers wearing ear phones, drunks staggering along the roadside, etc.).
IMHO, the car companies are spending billions of dollars on something that is going to be a total failure. The lawyers are licking their chops.