Leveraging Systems Theoretic Process Analysis (STPA) for Efficient ISO 26262 Compliance 2021-01-0067

There has been a significant increase - both in the content of electronics and software in vehicles as well as in recalls attributed to these components and systems. The advanced features, including the onset of autonomous vehicles accompanied by millions of lines of code in software have exponentially increased the complexity of vehicle systems and decreased effectiveness of many of the safety analysis techniques being used to identify hazards and safety requirements - for example, FMEA, FTA, ETA, etc.- which were invented decades before the existence of complexities of such magnitude.

This paper examines a new hazard identification technique formalized by Nancy G Leveson of Massachusetts Institute of Technology (MIT), USA in her book “Engineering a Safer World” and further elaborated in the STPA Handbook co-authored with John P Thomas in March 2018. This paper explains how the STPA technique could be effectively used to comply with ISO 26262 in various phases of the “V” lifecycle of product development and later during production, operation, service, and decommissioning. It is interesting to note that although STPA is referenced in the Standard for Safety for the Evaluation of Autonomous Products, UL 4600, the ISO 26262:2018 standard second edition makes no explicit reference to this technique although it allows practitioners to use any suitable technique so long as evidence can be provided that the objectives of the applicable clauses are met. Some reference(s) to prior work in this context will also be provided.