Formal Safety Analysis of a Radio-Based Railroad Crossing Using Deductive Cause-Consequence Analysis (DCCA)

In this paper we present the formal safety analysis of a radiobased railroad crossing. We use deductive cause-consequence analysis (DCCA) as analysis method. DCCA is a novel technique to analyze safety of embedded systems with formal methods. It substitutes error-prone informal reasoning by mathematical proofs. DCCA allows to rigorously prove whether a failure on component level is the cause for system failure or not. DCCA generalizes the two most common safety analysis techniques: failure modes and effects analysis (FMEA) and fault tree analysis (FTA). We apply the method to a real world case study: a radio-based railroad crossing. We illustrate the results of DCCA for this example and compare them to results of other formal safety analysis methods like formal FTA.