This is an interesting metric. Although self driving test cars are rare, the whole point of their existence is to drive so they probably clock more hours than a normal car.

About 5400 pedestrians are killed each year in the US. US drivers go 3.1 trillion miles a year. So they kill a pedestrian about every 5.7 billion miles. Last November, Waymo said they had 4 million self driven miles, so well short of statistically expecting to hit a pedestrian. In September of some unspecified year Axios claims Uber had self driven over 1 million miles.

My estimate needs help, the distribution of pedestrian bearing roads and pedestrian free roads likely does not match from my total miles per year number and what carbot testers cover. Also, this may have been a cyclist death, which adds another 800 or so deaths per year.

But, in any event, in rough numbers, Uber appears to have beat their expected time to pedestrian fatality by two or three orders of magnitude.