An International Standard for functional safety, ISO 26262, aimed to avoid failure in safety related electrical and electronic systems in passenger cars, is under development. A correspondent standard for heavy vehicles is expected in a few years time. Therefore the heavy vehicle manufacturer Scania has initiated this master thesis to be able to judge the current state of the company in comparison to the draft of ISO 26262 that is present at this point of time.
In this master thesis the requirements of some parts of ISO 26262 is compared to how the development is performed at Scania. The parts handled are concerning: early stages in the development; management of functional safety; requirements specification and management; and integration and testing. Many documents were read and several interviews were conducted to investigate how the development is performed at Scania to be able to analyze the gap to the requirements of ISO 26262. The result of the analysis was discussed with and verified by authorised persons at Scania.
The comparison shows that the most significant difference between Scania and ISO 26262 is the so called ASIL classification and derivation of requirements. ASIL classification is demanded in ISO 26262 as a way to know what efforts are required to achieve functional safety, i.e. what requirements in ISO 26262 to follow. Because of that, the ASIL classification impacts the performance of large portions of ISO 26262. At Scania, no ASIL classification is performed and to be able to comply with ISO 26262 this has to be done.
Derivation of requirements is connected to the ASIL classification, since the ASIL class of a requirement is inherited by the requirement(s) derived from that requirement. In ISO 26262, four levels of requirements have to be derived. To be able to know what requirements in ISO 26262 to follow when developing and testing at the different levels, derivation of requirements has to be performed. This means that derivation of requirements also impacts the performance of other parts of ISO 26262. At Scania, derivation of requirements is not performed as required in ISO 26262 and to be able to comply with ISO 26262 this has to be done.