I did read the RAND paper, when it came out months ago, and I double-checked the traffic accident per mile citation and the power calculation as well. Their point is irrelevant because their fleet size estimate is ludicrously small, and their statistics is a little dodgy as well: it should be a one-tailed test (since the important question is only if the Tesla is worse than a human driver), and if one wanted to debate the statistics, this is somewhere that Bayesian decision theory minimizing expected lives lost would be much more appropriate, and that approach would roll out self-driving cars well before a two-sided binomial test yielded p<0.05.