Waymo's 68% Lower Accident Rate: Superior Control or Survivorship Bias?

Last week, while debugging an autonomous driving simulation test, my first reaction upon seeing this IIHS report was, "The 68% figure is likely underestimated." Don't be surprised too quickly—I'm not saying Waymo is unsafe, but rather that this comparison itself comes with "unfair" conditions. Human driver data represents the full sample set, whereas Waymo's test scenarios are filtered/selected.