Automatic Steering and Functional Safety – an Application of IEC 61508

This paper describes the approach used, in accordance with IEC-61508 Standard, to define and allocate the safety requirements of a Magnetic Guidance System applied to urban buses. This paper covers the concept and design activities specific to the system safety lifecycle encompassing the Concept, Overall Scope Definition, Hazard and Risk Analysis, Overall Safety Requirements and Safety Requirements Allocation phases. Highlights of the adopted methodology include the application of the Controllability principle for determining the system risks, and the relevant role played by the FTA (Fault Tree Analysis) technique.