US study: Waymo's autonomous vehicles are safer than human drivers - by a large margin

Waymo's autonomous vehicles (a subsidiary of Google) are involved in 68% fewer traffic accidents than vehicles with human drivers, according to a study by the Insurance Institute for Highway Safety (IIHS).

"The results show that driverless cars are safer than human drivers, who can be tired or suffer from a lack of attention," said IIHS President David Harkey.

The Federal Highway Safety Administration requires autonomous driving companies to report accidents in which their vehicles were involved. For the purpose of the report, researchers collected Waymo reports from July 2021 to December 2024, alongside data on the number of miles traveled in autonomous mode. The data was compared to the accident rate per mile for human drivers in cities where Waymo operates at scale: San Francisco, Phoenix, Los Angeles, and Austin.

Analysis showed that, relatively speaking, Waymo vehicles were involved in more than two-thirds fewer accidents than human drivers. The largest difference was in rear-end collisions, where vehicles were involved in 91% fewer accidents, followed by single-vehicle accidents (85% fewer). In side-impact collisions, the difference was 77%, and in front-to-side collisions, 61%. Interestingly, Waymo vehicles were involved in 40% fewer accidents where the autonomous vehicle was rear-ended by another vehicle.

Furthermore, the blame for accidents rarely fell on the autonomous vehicle: in only 17.2% of cases was the Waymo car the striking vehicle, and in only 15.6% was it the primary contributor to the accident. Accidents involving pedestrians, cyclists, or motorcyclists were very rare—only 20 cases—and in only 3 of them was Waymo the striking vehicle.

"These are encouraging signs for the future of driverless cars. Now we need a comprehensive data collection system so that we can ensure that this level of safety is maintained as technologies become more common," said lead researcher Eric Tao.