Operational and System Hazard Analysis in a Safe Systems Requirement Engineering Process - Application to automotive industry

Automotive engineers have to meet evolving customer expectations, particularly growing concerns for safety, by introducing new sophisticated devices like Line Keeping Assistance, Collision Mitigation Braking System or Pedestrian Detection. These devices are composed of electrical components. They are likely to be subject to failures that may impact automobile safety, which means the safety of the vehicle occupants or pedestrians. Recent standards like ISO 26262 aim at mitigating these safety problems. Automobile engineers must prove that they perform safety studies along the design process. Meanwhile, they have to cope with other changes in their engineering practices. Due to the goals of verifying the satisfaction of all requirements, the design offices have introduced new practices based on Systems Engineering (SE) which are based on models. SE tools or processes are based on a functional approach of the system in which dysfunctional aspects are missing. Thus, there is a need to integrate the safety domain into the SE framework in order to improve safety studies and the collaboration between systems engineers and safety specialists. This paper analyzes this issue by focusing on the definition of high-level (or vehicle-level) safety requirements. It proposes a Safe Systems Requirement Engineering Process and a method named Operational and System Hazard Analysis (O&SHA) that helps to specify the high-level safety requirements (called safety goals in ISO 26262). It is based on a Model-Based Systems Engineering approach (MBSE) which integrates safety aspects. The added value of the proposed method is illustrated by applying it to two case studies. (C) 2016 Elsevier Ltd. All rights reserved.