Monitoring of Congestion on Expressways and Provision of Information using Probe Data: an Initiative Regarding the Rehabilitation Work following the Great East Japan Earthquake

The influence of the Great East Japan Earthquake to the expressway was extensive. To complete the restoration work in two years, the authors conducted construction projects under traffic control throughout days and nights on long stretches of highway in multiple sections. Because of this traffic control, there is more traffic congestion than usual and the length of congestion was longer than usual. To decrease the trouble and accidents for the expressway users, it was necessary for the road operator to monitor the accurate congestion status and to provide information. However, since there are enough traffic measurement devices on the expressways in the Tohoku region, it is impossible to detect traffic congestion automatically. Therefore, the authors embarked on the automatic detection of congestion status by applying a probe data, which can be obtained from vehicles which run in the congested sections. This article reports on a new inspection involving the accuracy of monitoring the congestion status by using probe data.