Journal of JSCE, Vol. 1, 490-506, 2013 Special Topic - 2011 Great East Japan Earthquake (Invited Paper) HEAVY VEHICLE TRAFFIC FLOW CHANGES ON EXPRESSWAYS IN THE TOKYO METROPOLITAN AND SURROUNDINGS CAUSED BY THE GREAT EAST JAPAN EARTHQUAKE Arata WADA1, Hajime INAMURA2 and Takashi OGUCHI3 1Member of JSCE, Metropolitan Expressway Company Limited (Former Graduate Student at National Graduate In- stitute for Policy Studies) (1-4-1 Kasumigaseki, Chiyoda-ku, Tokyo 100-8930, Japan) E-mail: [email protected] 2Fellow of JSCE, Professor, Dept. of Civil Eng. And Management, Tohoku Institute of Technology (35-1, Yagiyama Kasumicho, Taihaku, Sendai 982-8577, Japan) E-mail: [email protected] 3Fellow of JSCE, Professor, Inst., Industrial Science, University of Tokyo (4-6-1 Komaba Meguroku, Tokyo 153-8505, Japan) E-mail: [email protected] This paper summarizes the detailed heavy vehicle traffic flow on expressways for three months from March 11, 2011 as a result of the Great East Japan Earthquake. Day-by-day traffic changes, compared with historical data, and analysis together with related statistics showed the following results: The Western route called Kan-etsudou experienced 20% increase in traffic caused by detour trip toward the disaster region Tohoku during the first week. From the fourth week until mid-July after the earthquake, the average traffic volume increased by 20% compared with 2010, and average trip length increased by 10%. One of the major reasons for this change was that ports in the Tokyo Bay area were used as alternative freight transport routes in place of damaged ports in Tohoku. The influence of the disaster to the Tokyo Metropolitan Expressway network was quite limited. Key Words : the Great East Japan Earthquake, expressway, heavy vehicle, traffic flow change 1. INTRODUCTION NEXCO), was also damaged by the earthquake. The damage spread over to 5,800 points in 22 routes of A great earthquake with 9.0 magnitude occurred in the 1,200km-long expressway. As a result of emer- Japan on March 11, 2011, resulting in catastrophic gency recovery works for 20 hours, the entire ex- damage to infrastructure in the Pacific Ocean side of pressway network became available for specially the Tohoku region. Immediately after the earth- designated emergency vehicles. quake, urgent lifesaving activities, transport of relief Various types of very specific traffic phenomena, material supplies, and emergency recovery of infra- which will be beneficial for traffic and transportation structure such as roads were implemented. With policies as well as research works in this field, were regard to the recovery of the road network, for ex- observed in the expressway network, including the ample, urgent recovery operation or the so-called Tokyo Metropolitan Expressway. These phenome- comb strategy was successfully carried out by the na, however, were far from the normal business and Tohoku Regional Development Bureau, Ministry of routine jobs of the firm, thus, staff members were Land, Infrastructure and Transport. About 97% of reluctant to analyze the data and/or store the data for the road network was functional within one week future requirements. Those data sets were, therefore, from day 1 and all towns and villages, including quite perishable. some detour routes, were connected within one This paper aims to find out the real situation of the month. The elevated expressway network operated emergency traffic on the highway and to analyze the by East Nippon Express Company Ltd. (hereafter background of their time series changes. Since the 490 study focuses on the physical distribution and logis- (2) Study period and data sets tics, three months worth of data of trucks/trailers The earthquake broke out on March 11, 2011. The were analyzed for this purpose. study period was subdivided into three periods for Nakagawa and Kobayashi3) analyzed the traffic convenience: changes on the urban toll road caused by the great 1) From March 14 to 18 or the first week Hanshin-Awaji earthquake. Kim et al.4) estimated 2) From March 22 to April 15 or the second to fifth the economic loss caused by the detour by the cut-off week network. Tanaka and Yonekawa5) studied the time 3) After April 18 to June 17 or after six weeks. series changes of traffic at the border between Weekly-based average traffic using five weekdays Hanshin Expressway and other highways after the (Mon. to Fri.) was calculated. Because use of earthquake. There is no detailed traffic study of a Tohoku Exp. became free of charge from July 20, wide area, such as the Kanto Plain with 40,000 km2, 2011, traffic conditions drastically changed after affected by the large-scale disaster. that. After the East Japan Great Earthquake, many The data sets used for analysis are as follows: research committees and groups have conducted 1) Traffic volumes on Tokyo Metropolitan Ex- various traffic studies. Although these groups have pressway by vehicle detectors data published many reports and papers, all studies have 2) Traffic volumes on other expressway by vehicle focused on some specific sections of the expressway detectors data and/or highway or on short time period of at most two weeks. Three months after the disaster, Shimizu6) compared the traffic volume with the traffic before the disaster. This paper aims to summarize the detailed heavy vehicle traffic flow on expressways for three months from March 11, 2011 resulting from the Great East Japan Earthquake. Day-by-day traffic changes, comparison with historical data, and analysis, together with related statistics, were carried out. 2. METHODOLOGY (1) Study areas As illustrated in Fig.1, the study area and study network cover some 400km2 and 1600km, respectively. These routes are the Tohoku Expressway (hereafter Exp.), Kan-etsu Exp., Jo-ban Exp. as a radial network, Ban-etsu Exp., and Fig.1 Study Area. Kita-Kanto Exp. as a circular network, besides the Tokyo Metropolitan Exp. Table 1 Study Routes. Expressway Nickname Type Cover area Section Tohoku Expressway Tohoku Do Radial A part KawaguchiKohriyama Joh-Ban Expressway Joh-Ban Do Radial A part MisatoIwaki Kan-Etsu Expressway Kan-Etsu Do Radial Whole Line NerimaNagaoka Hoku-Riku Expressway Hoku-Riku Do Radial A part NagaokaNiigata Chuo Nihon-Kai Tohoku Expressway Nihon-Kai Tohoku Do Radial Whole Line Niigata ChuoArakawa Tainai Ban-Etsu Expressway Ban-Etsu Do Ring Whole Line IwakiNiigata Chuo Kita-Kanto Expressway (west) Kita-Kanto Do Ring A part TakasakiIwafune Kita-Kanto Expressway (east) Kita-Kanto Do Ring A part Tochigi-TsugaMito-Minami Higashi-Mito Expressway Higashi-Mito Do Ring Whole Line Mito-MinamiHitachiNaka Syutoken-Chuo-Renraku Expressway(east) Ken-Oh Do Ring A part InashikiTsukuba-Cho Syutoken-Chuo-Renraku Expressway(west) Ken-Oh Do Ring A part Hachi-OjiOkegawa-Kitamoto Tokyo-Gaikan Expressway Gaikan Do Ring Whole Line Oh-IzumiMisato-Minami Tokyo Metropolitan Expressway MEX Ring Whole Line Whole lines 491 3) O-D (from origin to destination) traffic volume (2) Time series changes in LVT on the East Japan on Tokyo Met. Exp. by ETC O-D data. Expressways (EJE) ETC: Electronic Toll Collection System a) General trend Because of the difference in data sources stated Fig.3 shows the time series changes in the average above, we refer to all expressways except Tokyo Met. traffic volume on the EJE. The average traffic is a Exp. as East Japan Expressway or EJE. Hereafter weighted average using the section length of two Tokyo Met. Exp. shall be referred to as TME. interchanges as the weight. After the event, traffic volume rapidly recovered in four weeks. The traffic (3) Target traffic volume hit a peak in the fourth week (March 28 to Because of the transportation demands of emer- April 1) after the event. Because of slightly less gency relief goods and materials for reconstruction traffic volume in 2010, the increment ratio against works, large-size vehicles such as trucks and trailers year 2010 hit the peak in the fifth week. The LVT rapidly increased on the expressways. This paper after the event increased more than 20% after the focuses on the large-size vehicle traffic, which in- East Japan Great Earthquake. Fig.4 shows the cludes mid-size trucks, large-size trucks, and changes in average trip length of LVT on EJE esti- king-size trucks/trailers depending on the limitation mated using ETC OD data. The trip length of LVT is of classification sensitivity of detectors. also increased by more than 10 % after the event. Changes in traffic volumes are increment or dec- rement amount from the traffic last year (2010). 3. CHANGES IN LARGE-SIZE VEHICLE TRAFFIC (LVT) (1) LVT before the disaster Fig.2 shows the percentage changes in LVT compared with the previous year by route during year 2006 and 2011. The previously increasing rate of LVT had decreased from 2006 to 2008. Because of the Lehman economic shock (crisis) in September of Fig.3 Weighted Average Daily Traffic Volume on East Japan 2008, LVT in 2009 decreased significantly. LVT Expressways (LVT: detector data). enjoyed economic recovery in 2010 until the disaster on March 11, 2011. Fig.2 The Percentage Changes of LVT for 6 Years. 492 b) Time series changes in small size vehicle traffic Although the LVT increased on all expressway (SVT) on the EJE networks in the study area after the fifth week, it was In order to identify the characteristics of LVT, obvious that Tohoku Do played a central role in the Fig.5 and Fig.6 demonstrate the same statistics of freight transport to the disaster region in Tohoku. small size vehicles (SVT) in the same period. We can identify a significant difference in average traffic volume and trip length between LVT and SVT. The LVT volume increased almost 20% compared with the previous year while the SVT maintained the volume level of year 2010.