Waymo published research in December comparing Waymo Driver's crash rates to human drivers' over 7+ million rider-only miles from Phoenix, San Francisco, and Los Angeles.

In a statement, Waymo said: "Our new research found that Waymo Driver performance led to a significant reduction in the rates of police-reported and injury-causing crashes compared to human drivers in the cities where we operate."

Source: Waymo

"These reports represent a good-faith effort by Waymo to evaluate how the safety of its autonomous driving system compares with the safety of human driving. The results are encouraging and represent one step in our evolving understanding of autonomous driving safety," said David Zuby, Chief Research Officer of The Insurance Institute for Highway Safety (IIHS) after reviewing the papers.

In the study, Waymo compared the Waymo Driver's crash rates to human drivers' on multiple benchmarks, including comparing overall crash rates using data from fully autonomous operations only, rather than a mix of fully autonomous driving and human drivers.

Waymo stated, "Waymo Driver demonstrated an 85% reduction or 6.8 times lower crash rate involving any injury, from minor to severe and fatal cases (0.41 incidence per million miles for the Waymo Driver vs 2.78 for the human benchmark)" and "A 57% reduction or 2.3 times lower police-reported crash rate (2.1 incidence per million miles for the Waymo Driver vs. 4.85 for the human benchmark)."

"This means that over the 7.1 million miles Waymo drove, there were an estimated 17 fewer injuries and 20 fewer police-reported crashes compared to if human drivers with the benchmark crash rate would have driven the same distance in the areas we operate," Waymo points out.

Waymo also notes that "being safer than human drivers in aggregate" is just one way the company evaluates Waymo Driver's performance.