Functionality resilience in connected autonomous vehicles: a perspective to enhanced road vehicle safety

Widespread deployment of connected autonomous vehicles (CAVs) is hampered by road-vehicle safety concerns rooted in the intrinsic complexity of CAV systems and in the unpredictability of operational environments, spanning functional safety (FUSA), the safety of the intended functionality (SOTIF), and cybersecurity. To confront these complexity-driven challenges in a unified manner, this paper re-examines road-vehicle safety through a functionality-centered resilience lens. The classical risk triplet (events A, consequences C, uncertainties U) is recast as a resilience triplet (A, F, U), in which F denotes the set of system functionalities to be preserved under adversity. This re-framing moves the focus from after-the-fact consequence angle toward the real-time safeguarding of critical functions throughout an adverse event. Building on this view, the interrelation between resilience and road-vehicle safety is elaborated across FUSA, SOTIF, and cybersecurity, and recent advances in CAV resilience within each domain are systematically surveyed. The conceptual demarcation between resilience and related notions such as robustness, recovery, and fault-tolerance are then clarified, showing that a functionality-centered stance absorbs these attributes as complementary  phases of one unified objective. The paper closes with an open-issue discussion and future research avenues toward engineering resilient CAV systems.