Using STPA in Compliance with ISO 26262 for Developing a Safe Architecture for Fully Automated Vehicles

Abstract

Safety has become of paramount importance in the development lifecycle of the modern automobile systems. However, the current automotive safety standard ISO 26262 does not specify clearly the methods for safety analysis. Different methods are recommended for this purpose. FTA (Fault Tree Analysis) and FMEA (Failure Mode and Effects Analysis) are used in the most recent ISO 26262 applications to identify component failures, errors and faults that lead to specific hazards (in the presence of faults). However, these methods are based on reliability theory, and they are not adequate to address new hazards caused by dysfunctional component interactions, software failure or human error. A holistic approach was developed called STPA (Systems-Theoretic Process Analysis) which addresses more types of hazards and treats safety as a dynamic control problem rather than an individual component failure. STPA also addresses types of hazardous causes in the absence of failure. Accordingly, there is a need for investigating hazard analysis techniques like STPA. In this paper, we present a concept on how to use STPA to extend the safety scope of ISO 26262 and support the Hazard Analysis and Risk Assessments (HARA) process. We applied the proposed concept to a current project of a fully automated vehicle at Continental. As a result, we identified 24 systemlevel accidents, 176 hazards, 27 unsafe control actions, and 129 unsafe scenarios. We conclude that STPA is an effective and efficient approach to derive detailed safety constraints. STPA can support the functional safety engineers to evaluate the architectural design of fully automated vehicles and build the functional safety concept.

Enhancing reliability analysis of AI systems using STPA: a case study on the DroneResponse UAV system

“…Many scholars have proposed improvement methods for STPA. Abdulkhaleq et al [8] combined the STPA method with the ISO 26262 standard and proposed a safety analysis method for developing safety architectures in autonomous driving car development. This research adopts a combination of STPA, FTA (Fault Tree Analysis), and FMEA (Failure Mode and Effects Analysis) to ensure the safety of modern automotive systems during the development cycle.…”

On ISO 26262 Compliance and Safety Assurance for Autonomous Vehicles using STPA

“…By repeatedly applying STPA, more risks could be identified [9]. Abdulkhaleq, A. et al (2017) presented the concept of how to use STPA to extend the safety scope of ISO 26262 and support the Hazard Analysis and Risk Assessments (HARA) process. As a result of verification by applying it to Continental's current fully automated vehicle project, it was concluded that STPA is an effective and efficient approach for deriving detailed safety constraints [10].…”

A Functional Safety Assessment Method for Cooperative Automotive Architecture

“…Studies to derive FSRs from the vehicle perspective present different mechanisms to generate safety goals and map these to the functional architecture using safety analysis methods. For instance, Beckers et al [7] presents a model-based method to define FSRs given safety goals while Abdulkhaleq et al [1] uses system theory for safety analysis.…”

“…Traffic congestion was estimated to cost 305 billion dollars in 2017 to traffic participants in the United States of America. 1 With continuously increasing urban population [3], traffic congestion will continue to be an inevitable problem for the foreseeable future. Around 70% of all goods transported around the United States are moved by trucks, and the lion's share of the cost for operating trucks comprises fuel costs and driver salary [54].…”