Abstract
In this paper, daily traffic volumes on highway networks damaged in the 2016 Kumamoto Earthquake Disaster were spatiotemporally visualized and analyzed. The network functions of highways in Kumamoto and Oita prefectures were severed immediately after the main shock. Once the traffic restrictions and controls were lifted, traffic volumes got back to normal after mid-May. Next, in order to understand an initial response after an earthquake, trends of restoration and traffic flow, average daily travel speeds were also shown. Moreover, three kinds of highway network performance measures were assessed. Two physical measures describing the number of sections and total distances opened to traffic decreased by approximately 60% to 100% than normal in Kyusyu expressway and Oita expressway, while the functional measure describing traffic volumes decreased by approximately 50% to 80%. Each measure got back to normal within three weeks after the earthquake. Comparison with the past two catastrophic disasters, the Great Hanshin-Awaji Earthquake Disaster and the Great East Japan Earthquake Disaster were made. The functional measures were consistently lower than the physical measures, reaching the pre-quake level after the physical measures completely recovered.
