Comparison of Automated Vehicle Struck-from-Behind Crash Rates with National Rates Using Naturalistic Data

Automated vehicle developers in California are required to submit records of crashes and distances traveled in autonomous mode for all vehicles in their fleets. Several studies have investigated this database to compare automated vehicle crash rates with national rates. Although automated vehicles are struck from behind in 73% of their autonomous mode crashes, this is the first study to compare automated vehicle struck-from-behind crash rates to national rates using equivalent crash definitions. Rear-end collisions have substantial public health and economic impacts, representing a third of all collisions and $3.9 B in annual economic costs. In this study, automated vehicles were found to be struck from behind while in autonomous mode 17.2 (14.2–20.7, 95% CI) times per million-miles traveled, significantly higher than human-driven vehicles in naturalistic driving studies (3.6, 3.0–4.3, 95% CI). These differences narrow when comparing urban driving and business/industrial driving in the naturalistic driving studies with AV testing in similar environments. Automated vehicles were more likely to be struck when stopped than when moving, suggesting that automated vehicles’ decisions about where and when to stop at intersection are more plausible as contributing factors than unexpected rates of deceleration.

100th Annual Meeting of the Transportation Research Board