"How many miles would autonomous vehicles have to be driven to demonstrate that their failure rate is statistically significantly lower than the human driver fa

"How many miles would autonomous vehicles have to be driven to demonstrate that their failure rate is statistically significantly lower than the human driver failure rate? ... Suppose a fully autonomous vehicle fleet had a true fatality rate that was A=20% lower than the human driver fatality rate of 1.09 per 100 million miles, or 0.872 per 100 million miles. We apply Equation 7 to determine the number of miles that must be driven to demonstrate with 95% confidence that this difference is statistically significant ... It would take approximately 5 billion miles to demonstrate that difference. With a fleet of 100 autonomous vehicles test-driven 24 hours a day, 365 days a year at an average speed of 25 miles per hour, this would take about 225 years." This is from http://www.rand.org/pubs/research_reports/RR1478.html http://www.rand.org/pubs/research_reports/RR1478.html I'd love to hear any problems with RAND's analysis, because it'd be great for this to not be the case.