Stats based on NHTSA numbers, I believe. Would be very rough (not really apples to apples, at very least because Tesla has human supervision and Waymo is autonomous, but likely many other differences as well such as collection of driving routes), but better than anything else.
We probably couldn’t do even this rough calculation without NHTSA oversight.
Comparison of Tesla and Waymo incident rates:
We can easily compute the exact Poisson 95% confidence interval for this data.
[Tesla]
7 incidents in 250k miles: 11 to 52 incidents per million miles.[Waymo]
234 incidents in 128m miles: 1.6 to 2 incidents per million miles.[Ratio of Tesla to Waymo Incident Rate]
95% confidence interval for the ratio is about 8.87 to 23.76.In all this we assume constant average incident rate. And with continued development of both systems this assumption is quite shaky.
If we use 100m miles instead of 128m, then the interval is 8.03 to 22.61 times.