Hmm, I think that, in fact, this comparison is disingenuous! If you want to reduce net collisions, you want to compare to the mean, not median. In that case, once you've produced a self-driving car that's better than the mean, you're saving lives. You don't need to create a self-driving car which is better than every driver, ever.
SDC will only move the average upwards if they're taking less safe drivers off the road. If a 40% safe SDC replaces a 50% safe human driver, then you've shifted the average downwards.
