Investigating impacts of communication loss on signal performance with use of event-based data

Reliable communication in a traffic signal network is essential for responsive traffic management. However, communication malfunctions often go unnoticed by transportation agencies because of unfamiliarity with the potential problems and inefficiencies that can arise from poor communication quality. Therefore, this paper focuses on the critical effects of communication loss on data quality and signal coordination. On the basis of regionwide event-based data collected in the city of Tucson, Arizona, a data quality control method with criteria specifying the completeness of event-based data was proposed and implemented. The quantified analysis provides a better understanding of data completeness than is possible by simply scanning real-time monitoring states. The proposed method provides an effective tool that will enable practitioners to diagnose problems with missing data and to evaluate the health and capability of a communication network for event-based data collection. A further investigation of how signal performance is affected by communication loss found unexpected changes in traffic progression, a situation identified by using a statistical analysis method and evaluated by monitoring control delay. The evaluation results for test cases found significant increases in the control delays between 27% and 720% when communication losses occurred. This study provides an innovative data-driven approach that supports smarter asset management of signal communication networks and ultimately will enhance signal performance.