Traffic Control Systems


Impact of Errors on the Quality of Active Traffic Control Systems

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In the future, process-oriented quality management should be used to ensure the efficiency of the transport infrastructure in Germany in the field of collective traffic management systems. This research work achieved a complete process and quality model and practicable recommendations for actions to enhance quality for the entire life cycle of active traffic control systems. In order to develop a complete process model, existing designs of quality management systems of traffic control systems were used. The final process model is divided into the life cycle phases ‘planning’, ‘construction’, and ‘operation’ including maintenance, which supports the phase ‘operation’.

The process model contains 34 valuation-relevant processes. A failure mode and effect analysis (FMEA) was created and executed to identify problems in the quality assurance of the processes defined in the process model. On the basis of expert knowledge, failure and failure causes were analyzed and the most critical quality problems were identified. Based on the results of the process model, a quality model for a quantitative description of the effect of failures was developed. The concept of Bayesian network was used to systematically illustrate the impact of failures on following processes throughout the life cycle of active traffic control systems. The probabilistic quality model can also be used as a diagnostic tool for analyzing failure causes of observed disturbances of an active traffic control system.

As part of the research, practicable and resource-saving recommendations for action to enhance quality were derived, based on the results of the process model and compiled in a document for planners and operators of active traffic control systems. Additionally, a method to estimate the benefit of the recommendations was described for justify the required investment for quality assurance. The focus of future research should examine the adaption of the quality model to a specific active traffic control system, in particular the optimization of the model topology. Furthermore, it should be analyzed whether the elaborated results of research can be applied to other types of traffic control systems



Federal Ministry of Transport and Digital Infrastructure, represented by the Federal Highway Research Institute


Dr.-Ing. Adrian Fazekas

Year of Completion