A Survey on Enhancing Autonomous Vehicle Safety through Fault Tree Analysis and SOTIF Integration

As autonomous vehicles continue to evolve and integrate into modern transportation systems, ensuring their safety in uncertain and dynamic environments remains a critical challenge. Fault Tree Analysis (FTA) is widely applied in autonomous vehicle risk assessments, offering structured insights into system failure. However, traditional FTA mainly address hardware and software malfunctions, while hazards arising from functional insufficiencies remain less systematically explored. The Safety of the Intended Functionality (SOTIF), outlined in ISO 21448, focuses on these non-fault-based hazards. There is a lack of surveys that thoroughly investigate FTA within the SOTIF context to comprehensively address both malfunction-induced and functionality-induced risks. It is valuable to bridge the traditional risk analysis with SOTIF-specific hazard evaluation through a dedicated review. This survey reviews the fundamentals and key challenges of autonomous vehicle systems and FTA, and discusses how FTA can be adapted to support SOTIF-based safety assessments. Qualitative and quantitative FTA methods are summarized, along with advanced extensions like Bayesian Networks and Dynamic FTA. The survey highlights the critical research trends in integrating FTA with SOTIF for autonomous vehicle safety assurance. Finally, current challenges, opportunities and future directions of use of FTA within the SOTIF framework are outlined to enhance risk analysis frameworks for next-generation autonomous vehicles.