Improvement of Congestion Detection on Expressways

This paper develops a method of improving congestion detection in urban motorway traffic surveillance and control systems in Japan. When developing motorway traffic surveillance and control systems, accurate congestion detection is often difficult or impossible because of the disturbances due to the oscillation of congested traffic flow. To improve the accuracy of congestion detection, it is necessary to distinguish noncongested flow from congested flow. Traffic flow data for the Tokyo Expressway and the Keiyo Expressway were collected. Computer experiments were carried out to develop a test to improve the accuracy of congestion detection on urban expressways. Applying the reference value proposed in this study greatly improved the accuracy of congestion detection.