An Integrated Approach to Requirements Development and Hazard Analysis

The introduction of new safety critical features using software-intensive systems presents a growing challenge to hazard analysis and requirements development. These systems are rich in feature content and can interact with other vehicle systems in complex ways, making the early development of proper requirements critical. Catching potential problems as early as possible is essential because the cost increases exponentially the longer problems remain undetected. However, in practice these problems are often subtle and can remain undetected until integration, testing, production, or even later, when the cost of fixing them is the highest.In this paper, a new technique is demonstrated to perform a hazard analysis in parallel with system and requirements development. The proposed model-based technique begins during early development when design uncertainty is highest and is refined iteratively as development progresses to drive the requirements and necessary design features. The technique is evaluated by applying it to a realistic but generic Shift-By-Wire design concept in two iterations with varying levels of detail. In addition, as the requirements and design evolve and change over time, the changes can be immediately analyzed for new hazards without repeating the entire analysis. The approach is also applicable even before requirements are developed, providing feedback when some of the most important decisions are being made instead of waiting for a finished design or model to begin an analysis. In this way, potential issues can be identified immediately and more efficiently, thereby reducing the need for future rework.