[asift]

1.25 per 100 million miles is almost certainly a bad benchmark since the majority of those miles are interstate miles. Fatality rate per mile of urban driving would be much better, although I'm not really sure whether I would expect that number to be higher or lower.

Edit: Actually, maybe I'm wrong in assuming (a) the majority of miles driven are interstate miles, or (b) that the majority of existing miles logged by self-driving cars have not been on the interstate. Would love to see some data if anyone has it, although I suspect Google, Uber, et al. are reluctant to share data at this point.