Advancing Functional Safety in Automated Driving: A Methodological Approach to Legacy System Integration under ISO 26262

Abstract: This article presents a novel method for enhancing the design of Functional Safety Concepts (FSC) in automated driving systems, addressing the challenges of integrating legacy components within the ISO 26262 framework. The proposed approach systematically leverages existing diagnostic specifications of legacy subsystems to assess their impact on safety-critical functions, producing abstracted reports suitable for vehicle architects. This method facilitates the creation of Preliminary Architectures (PA) and supports FSC verification argumentation. Tested on a safety-critical braking subsystem at Scania C.V. AB, the approach demonstrates several benefits: effective reuse of existing work products, comprehensive requirement gathering for automated driving, efficient parallelization of work across expertise domains, and broad applicability to various subsystems. Results indicate that this method not only enables cost-effective and robust design but also aligns with evolving industry standards for safety in automated driving systems. The article concludes by discussing the implications of this approach for the automotive industry and suggesting directions for future research in functional safety concept design