Waymo Driverless Cars Crash 68% Less Often Than Human Drivers, IIHS Study Finds
Independent analysis validates Alphabet subsidiary's safety claims across four cities while exposing critical regulatory data gaps.
Waymo's driverless vehicles crashed 68% less often than human drivers from 2021 to 2024, according to a study released Wednesday by the Insurance Institute for Highway Safety (IIHS).
The analysis compared approximately 50 million miles of Waymo's driverless operation against 222 billion miles driven by humans in San Francisco, Phoenix, Los Angeles, and Austin—one of the first comprehensive independent comparisons of autonomous vehicle safety against human benchmarks.
Safety Metrics Show Significant Gap
Waymo vehicles experienced 85% fewer single-vehicle crashes and 81% fewer injury crashes per mile than human drivers, the IIHS found.
In absolute terms, human drivers crashed 4.06 times per million vehicle miles traveled, while Waymo's robotaxis crashed 1.28 times per million miles.
Performance varied by city. Phoenix showed the largest safety advantage at 76% fewer crashes, followed by Los Angeles at 71% and San Francisco at 35%. Austin was the outlier, with Waymo vehicles involved in 4% more crashes than human drivers.
Independent Validation After Years of Self-Reporting
Previous safety claims from Waymo, a subsidiary of Alphabet Inc., relied primarily on internal company data. The IIHS study applied what it called a "common-sense standard" to filter police-reportable crashes from the National Highway Traffic Safety Administration's Standing General Order database, excluding minor incidents like undercarriage scrapes that human drivers typically would not report.
"The results show that, on a limited scale, these driverless cars are safer than human drivers — who can be impaired or drowsy or suffer lapses in attention," said David Harkey, IIHS president.
Data Collection Gap Raises Oversight Concerns
Despite the positive findings, the IIHS emphasized a critical regulatory weakness: companies must report crashes but are not obligated to report miles logged, making the present data collection system inadequate for continuous monitoring of large-scale expansion.
This gap makes it nearly impossible to independently verify safety performance for any autonomous vehicle company that does not voluntarily share its vehicle miles traveled data.
"Now we need to get the data collection system right, so that we can ensure that level of safety continues as these technologies become more prevalent," said Eric Teoh, IIHS director of statistical services.
The study validates Waymo's safety claims while underscoring that federal and state oversight infrastructure has not kept pace with the deployment of Level 4 autonomous technology.