Uncertainty-Aware Probabilistic Risk Quantification of SOTIF for Autonomous Vehicles

Ensuring the Safety of the Intended Functionality (SOTIF) for autonomous vehicles (AVs) is critical. Effective risk assessment helps AVs make decisions and avoid risks. However, existing methods face challenges due to environmental uncertainties, insufficient multi-dimensional risk quantification, and limited predictive accuracy. To address this challenge, we propose an uncertainty-aware probabilistic risk assessment framework that quantifies the risk of AVs violating safety constraints and calculates the expected average severity of such violations in uncertain environments. We first establish a general SOTIF risk model to characterize the static risk of the AV and surrounding traffic participants. Following this, we introduce a method for predicting dynamic uncertainty risks, resulting in probabilistic risk quantification. This framework accounts for multi-dimensional uncertainties and enhances safety under dynamic conditions. Extensive evaluations across typical traffic scenarios-including highways, intersections, and roundabouts-demonstrate that our method outperforms typical algorithms like Time Headway (THW) and Time-toCollision (TTC). Empirical studies in extreme scenarios further validate the framework's ability to reduce risks and improve system generalization. The related code is available at: https://github.com/idslab-autosec/risk-uncertainty.