# Waymo's driverless cars crashed 68% less often than human drivers in four cities > A four-city comparison of driverless and human crash rates, with the limits IIHS states. By Ryan Porter ยท Published 2026-11-09 Canonical: https://machines-on-machines.anth.us/posts/waymo-four-city-crash-study/ ::image{src="assets/waymo-four-city-crash-study/waymo-four-city-crash-study.jpg" alt="A white Waymo Jaguar I-Pace at a traffic light in San Francisco" credit="Image: 9yz, CC BY 4.0, via Wikimedia Commons."} A Waymo vehicle in San Francisco, one of the four cities in the study. [Image source](https://commons.wikimedia.org/wiki/File:Waymo_Jaguar_I-Pace_-_Front_Quarter_View_02.jpg). [Licence](https://creativecommons.org/licenses/by/4.0/). Waymo's driverless vehicles were involved in police-reportable crashes at a rate 68 percent lower per mile than human drivers, according to a July 2026 study by the Insurance Institute for Highway Safety (IIHS). The comparison covers 2021 to 2024 in San Francisco, Phoenix, Los Angeles and Austin: about 50 million driverless Waymo miles against human driving on the same roads. The gain was not the same everywhere. Phoenix was 76 percent lower, Los Angeles 71 percent and San Francisco 35 percent. In Austin, Waymo's rate was 4 percent higher, which IIHS attributes to a relatively small sample. Across the four cities, Waymo had 85 percent fewer single-vehicle crashes and 81 percent fewer injury crashes per mile. Human crashes are under-reported, so IIHS compared like with like. It kept only the Waymo crashes a person would typically report to police, and it noted that around half of all crashes and a third of injury crashes go unreported. Waymo is the only company that voluntarily provides driverless mileage, so no other system could be compared. IIHS concludes that "on a limited scale" driverless cars are safer than human drivers. It also says the current data system is not good enough to monitor a large-scale expansion. For the wider question of what "safer than a human" does and does not mean, see [What the evidence says about driverless and human crash rates](/articles/waymo-driverless-cars-are-safer-than-human-drivers/). [Read the source](https://www.iihs.org/news/detail/waymos-driverless-cars-crash-less-often-than-people).