The Insurance Institute for Highway Safety (IIHS) has published a study showing that Waymo autonomous taxis crash 68% less than the average human driver per vehicle mile traveled. The study analyzed federal crash reporting data for robotaxi services from 2021 to 2024.
Waymo's crash rate compared to 4.06 for human drivers.
Waymo vehicles traveled approximately 50 million miles autonomously during the study period, while human drivers covered about 222 billion miles in the same areas. Per million vehicle miles traveled, human drivers had a crash rate of 4.06, compared to Waymo's rate of 1.28.
The results varied by city. Waymo's crash rate was 76% lower in Phoenix, 35% lower in San Francisco, and 71% lower in Los Angeles compared to human drivers. In Austin, Waymo had a 4% higher crash rate, which some sources attribute to a small sample size.
Waymo vehicles were involved in 85% fewer single-vehicle crashes and 81% fewer crashes resulting in injuries per vehicle mile traveled than human drivers, according to the IIHS study. However, Waymo had a higher share of crashes in dark conditions than human drivers. Half of Waymo's crashes occurred on streets with speed limits under 25 mph, compared to 8% of human crashes.
Nearly half of Waymo's miles were driven with no humans in the vehicle. The IIHS study also notes that only 22% of the 736 reported autonomous-vehicle crashes during the study period were likely to be police-reportable. Of those 736 crashes, 89 involved Waymo vehicles, and only 64 of those were in autonomous mode.
The IIHS estimates that around half of crashes and a third of injuries go unreported by human drivers, which could affect comparisons. Additionally, Waymo does not operate on highways, a factor that may influence crash rates.
Those are encouraging signs for the future of driverless vehicles. Now we need to...
Previous studies by Waymo employees, submitted for peer review, have also reported safety benefits. A 2023 study found that Waymo vehicles reduce injury-causing crashes by 85% and police-reported crashes by 57%. A 2025 study claimed Waymos are 25 times safer for pedestrians and cyclists.