Safety assurance at GM and using model management to support it

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When a vehicle is designed, the car maker - the Original Equipment Manufacturer (OEM) - makes every effort to ensure that the vehicle will be safe and reliable. As vehicles have increased in complexity with the addition of software-enabled hybrid powertrains and Advanced Driver Assistance Systems, the system design and safety processes have had a corresponding increase in required effort and difficulty. Recently, seemingly minor incremental changes in the vehicle's software and/or physical design have resulted in safety recalls because of unforeseen subsystem interactions that have reduced vehicle safety and/or reliability to unacceptable levels. To help address these issues, OEMs and their suppliers collaborated to produce the standard ISO 26262 Road Vehicles - Functional Safety, which prescribes processes and their outputs that should be produced as part of the system, software and safety processes for vehicle features that require different Automotive Safety Integrity Levels. As OEMs and suppliers strive to be consistent with ISO 26262, an increasingly important question arises: when can design and safety assurance artefacts be safely reused and when do the processes and the resulting work products have to be redone? Automotive companies must address this key question if they want to remain competitive and be able to deliver ever safer vehicles at a purchase cost that the public is willing to pay. To help the Canadian automotive industry address this issue, this project will model the design and safety artefacts and their relationships with explicit safety assurance arguments known as a (safety) assurance case. We will provide model management processes and tools to analyze the models and determine the impact of a design change on the assurance case. This will help engineers determine which parts of the assurance case can be safely reused and where it requires further engineering effort to demonstrate that the new system is acceptably safe. The work will be extended to manage models of safety assurance for entire product lines to help OEMs deal with the reality of manufacturing for global product development.