Current averages for the US are around 10 per billion miles and decreasing; best countries in Europe are already below 5 per billion miles.

There's some really interesting progress both on vehicles monitoring driver attention, and on monitoring for alcohol in the air, that would yield substantial improvements even beyond 2019 tech. I have no doubt we'll see fatality rates below 1 per billion miles in Western Europe within a decade.

The corollary of the statistics quoted above is that you need to observe your self-driving vehicle system over tens of billions of miles before you even know if you're safer or not.