Industrial Experiences of Building a Safety Case in Compliance with ISO 26262

The ISO 26262 functional safety standard provides appropriate development processes, requirements and safety integrity levels specific for the automotive domain. One crucial requirement consists of the creation of a safety case, a structured argument, which inter-relates evidence and claims, needed to show that safety-critical systems are acceptably safe. The standard is currently not mandatory to be applied to safety critical systems installed in heavy trucks, however, this is likely to be changed by 2016. This paper describes the experience gathered by applying the standard to the Fuel Level Estimation and Display System, a subsystem that together with other subsystems plays a significant role in terms of global system safety for heavy trucks manufactured by Scania. More specifically, exploratory and laborious work related to the creation of a safety case in compliance with ISO 26262 in an inexperienced industrial setting is described, and the paper ends with presenting some lessons learned together with guidelines to facilitate the adoption of ISO 26262.