The proposed UL 4600 standard focuses on ensuring that a comprehensive safety case is in place, including safety claims, argumentation, and evidence. It is intended to cover computer-based system aspects of autonomous operation. It is specifically designed to build upon the strengths of existing standards such as ISO 26262, and evolving standards such as ISO 21448-SOTIF. It is not a competing standard to those and other standards being developed. UL 4600 permits claiming appropriate credit for conforming to those standards while ensuring autonomy-specific gaps are filled.
Areas of specific emphasis include safety practices for machine learning-based approaches, functionality for which complete requirements are not available, addressing “unknown unknowns” in safety argumentation, and ensuring that adequate fault mitigation capabilities are present in systems that do not have oversight by human drivers. We anticipate that many users of the standard will, in fact, build upon existing ISO 26262 and newly created ISO 21448-SOTIF conformance strategies, and we believe these standards complement UL 4600.