STPA‐based analysis of driver misuse risk scenarios in level 3 automated driving

Abstract

This paper proposes an analytical framework that integrates the SOTIF perspective with System‐Theoretic Process Analysis (STPA) to systematically analyze driver misuse in Level 3 automated driving environments. In Lv.3 systems, drivers must intervene when Takeover Requests (TOR) occur, making misuse a critical safety risk even when the system operates as intended. Driver misuse is modeled as inadequate control actions within the control structure, and the four psychological states that induce misuse—overtrust, distrust, distraction, and interference—are treated as the causal factors of those unsafe control actions. Following the STPA procedure, 41 causal scenarios were derived and evaluated using severity, likelihood, and controllability. Clustering analysis was then applied to identify recurring risk patterns and representative Risk Archetypes. The results show that many high‐risk scenarios are strongly related to drivers' failures to perceive or properly respond to TOR. The proposed framework provides a structured basis for understanding driver misuse risks and supports the design of driver monitoring, improved HMI strategies, and multilayer safety assistance mechanisms.