JSTE Journal of Traffic Engineering
Online ISSN : 2187-2929
ISSN-L : 2187-2929
Volume 4 , Issue 1
Showing 1-48 articles out of 48 articles from the selected issue
Special Edition A (Research Paper)
  • Koki HIOKI, Masahiro TADA, Katsuhiro IIDA, Masaya OKADA, Kazumi RENGE
    2018 Volume 4 Issue 1 Pages A_1-A_7
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    In this study, we measured and analyzed elderly drivers' behavior (gaze position) in real traffic conditions including traffic scenes such as turning left/right busy intersections, driving narrow residential streets, etc. using eye camera to investigate when and how elderlies behave riskily. By comparing measured gaze position data of 24 elderlies and those of 14 non-elderlies, we found out that elderlies performed significantly less scanning behavior than non-elderlies when (1) turning right at a busy intersection where driver should simultaneously pay attention to multiple vehicles, bicycles and pedestrians around, (2) passing through an intersection of narrow residential streets without any traffic sign indicating location/risk of the intersection. We also found that elderlies tended not to check safety of backside of vehicle while braking as he approached to an intersection with stop sign. In addition to these, the number of elderlies' visual confirmation to the overhead mounted stop sign is significantly less than non-elderlies'.

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  • Ryota ISHIYAMA, Azusa GOTO, Hideki NAKAMURA
    2018 Volume 4 Issue 1 Pages A_8-A_16
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    In Japan's unsignalized crosswalks on basic road sections, it is hard to say that safety and efficiency of crossing pedestrians are sufficiently ensured. On the other hand, in recent years, attention has been paid to a "two-stage crossing", that is a method in which a crosswalk is split into two stages by using a median island. However, as application examples are still limited in Japan, it is necessary to quantitatively show its effect. In this study, stop-or-go decisions of pedestrians at crosswalks were analyzed considering the impacts of pedestrian crossing time as well as position and speed of approaching vehicles by using observed data. Based on that, the change of the critical gap at the time of applying the two-stage crossing was estimated by formulating a pedestrian gap acceptance model. In addition, the effect of improving efficiency was quantitatively evaluated, by calculating the average delay of crossing pedestrians using this critical gap.

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  • Mikiya ANDO, Shinji TANAKA, Fumihiko NAKAMURA, Shino MIURA
    2018 Volume 4 Issue 1 Pages A_17-A_22
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    At-grade intersections in highway network generally hold issues on safety and efficiency when traffic volume on those intersections increase. “Alternative Intersections” that is recently introduced especially in the US is one of the solutions for these issues to increase intersection capacity and to improve safety. It avoids conflicts between left-turn (right-turn in Japan) and oncoming through traffic, then realizes safer and more efficient situations in low cost compared with grade separation. It is important to estimate the capacity accurately when we design at-grade intersections, however, its actual value is not investigated sufficiently. This study evaluated the capacity of major three types of Alternative Intersections (MUT, RCUT and CFI) based on field observations. As a result, even intersections in the same control type showed different performance according to the geometrical characteristics and signal phase pattern. Also, comparison of different control types revealed different applicability of each type in conjunction with the demand conditions.

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  • Noritake HARADA, Tomoyuki INAGAKI, Satoru KOBAYAKAWA, Hideo YAMANAKA
    2018 Volume 4 Issue 1 Pages A_23-A_29
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    It's pointed out that drivers have to pay more attention for two-way traffic of bicycles on a sidewalk which many bicycles users pass through as customary in Japan. In this study, it is intended to identify the dangerousness of twoway traffic of bicycles on a sidewalk by analyzing near-miss accidents which were recorded a behavior on a driving recorder in case of heavy braking occurred. <br/>From the macro-analysis focusing on bicycle behavior, it is observed the difference of incidents condition based on passing positions of bicycle. It is also observed the difference of near-miss accidents type based on passing direction of bicycle. Furthermore, on an analysis of near-miss accidents on left turn vehicles at the signalized intersections of arterial streets, it is clear that a reversing bicycle on a sidewalk has a high risk because it conflicts with a vehicle more closely than the bicycle passing right way.

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  • Asami FUKAWA, Tomoyuki INAGAKI, Satoru KOBAYAKAWA, Yoshinori TERAUCHI
    2018 Volume 4 Issue 1 Pages A_30-A_37
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    Traffic accidents of children have been decreasing every year, but the countermeasures for traffic safety are still needed for more safety roads. Currently, education of traffic safety for children has mostly focused on “recognitions”because of the problems on characteristics at children’s road crossing. However, it may be caused children’s traffic accident by making a mistake in "decisions". Therefore, traffic safety education on "crossing decisions" is necessary as well as “recognitions of vehicles”. In this paper, experimental study was conducted to research about the parents’understandings of their children’s “crossing decision” who has the closest relationship on a daily life. As a result, there are gap between parents and children so that the parents are seems to believe that children are making “crossing decision” based on vehicle’s speed but children don't consider it when they cross a road. In addition, even though parents recognized the reality of the child who tends to make a mistake to a high-speed vehicle, they don't understand the seriousness of their mistakes.

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  • Katsuhiro IIDA, Yasuaki WADASAKI, Hisanaga SATO, Fumihiro ITOSHIMA
    2018 Volume 4 Issue 1 Pages A_38-A_46
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    In recent years, variable road information boards on expressways have become highly developed. However, due to differences in times of posting and renewal, these information boards are not uniform in graphical symbol designs and display methods of character information. Particularly, it has been pointed out that some graphical symbols among the present ones are not understood correctly by road users. In previous studies, graphical symbols were newly created and readability of 2-event information boards with symbols was reviewed. In this study, upon analyzing these previous study results, we tried to clarify issues of the display method in 2-event information boards. Furthermore, on the basis of these issues, we developed new display designs for information boards and verified the efficacy by evaluating their readability. As a result, it has been suggested that the intelligibility of the second event, which is a highly important issue, improves substantially by laying out two 1-event information boards alongside the other.

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  • Keisuke YOSHIOKA, Hideki NAKAMURA, Sumio SHIMOKAWA, Hirohisa MORITA
    2018 Volume 4 Issue 1 Pages A_47-A_54
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    For the safety performance and smooth operation of roundabouts, designing geometric elements that can realize appropriate driving behavior is an important issue, particularly regarding the S-shaped trajectory which is different from ordinary cross intersections. However in Japan, this kind of driving behavior characteristics on roundabouts has not yet been studied enough. In this study, video surveys for driving behavior by using an UAV were carried out at seven roundabouts with different geometric design and the impact of geometric design elements on driving behavior are analyzed. As a result, the entry corner radius and the turning angle which is formed by entry and exit legs are shown as critical factors for the lateral acceleration applied to the vehicle. Moreover, it is shown that oversized entry corner radius and turning angle smaller than 150 degrees could lead to lower lateral acceleration and result in lower speed control effect on straight through vehicles.

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  • Sumio SHIMOKAWA, Naoya KOYAMADA, Keisuke YOSHIOKA, Hirohisa MORITA
    2018 Volume 4 Issue 1 Pages A_55-A_63
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    In this study, we found the threshold values for the road structure conditions and others of two-lane and multilane road to permit a travel speed of 50 km/h with the goal of identifying the factors of road structures which made it impossible to achieve speed services for roads in which traffic functions and expected corresponding speed service is not achieved, and to develop the countermeasures for that purpose. In this study, we proposed an approach for analyzing the necessary and sufficient road structure conditions and based on the road traffic census data, analyzed the roads in Japan which are of a higher class than prefecture roads. And finally, we can confirm that it is likely that the obtained threshold value is able to be used for the analysis for the performance verification of the National Highway Bypass.

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  • Noboru ISE, Emi MINATO
    2018 Volume 4 Issue 1 Pages A_64-A_70
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    Recently, Michi-no-Eki is expected to be the area with various functions for regional revitalization in Japan. However, it might be difficult to introduce Michi-no-Eki considering regional characteristics, because the method to quantitatively evaluate the necessity of various functions has never been developed. In particular, little attention has been given to Michi-no-Eki for regional well-being which includes a supermarket, a playpark for children, a restaurant, and others. This study focuses on Michi-no-Eki for regional well-being and mainly aims to clarify the factors which influence on demand for Michi-no-Eki for regional well-being, in order to obtain fundamental knowledge to develop the method for quantitatively evaluating the necessity of Michi-no-Eki for regional well-being. As a result, we found that (1) local residents mainly use a supermarket in Michi-no-Eki and about 85% of them spend 1-3,000 JPY/time there and (2) six factors influence on demand for Michi-no-Eki for regional well-being in common with three scenario analyses.

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  • Eiji MORIMOTO, Tomohiro KOSHIKAWA, Mamoru TANIGUCHI
    2018 Volume 4 Issue 1 Pages A_71-A_79
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    To cope with Japan is declining population and aging society, a plan based on "Compact plus Networks" is progress in cooperation with regional public transportation services. To complement service facilities in core areas with a network linking them, service facilities must be agglomerated. Moreover, smooth movement between core areas using public transportation is important. This study was conducted to obtain information when each city considers a compact plus network through the Agglomeration rate of Service facilities in Urban core areas (ASU) and Travel time by Public transportation between Core areas (TPC). Results clarified the relation of ASU and TPC in each city, demonstrating the progress of "Compact plus Networks." In addition, results show that two important tendencies: 1) the TPC of many smaller cities tends to be more than 60 min, and 2) especially between core areas including a core area with a low ASU, complementary service facilities are needed.

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  • Syuji YOSHIKI, Hiroshi TATSUMI, Kayoko TSUTSUMI, Kensuke HAJI
    2018 Volume 4 Issue 1 Pages A_80-A_87
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    In accordance with “Guideline for creation of safety and comfort bicycle environment” established in 2012, bicycle lanes has been implemented all over Japan. Various types of bicycle lanes, painted other than blue, painted only a part of lanes and so on, have been seen because the guideline allows various method for coloring them. In implementation of bicycle lanes, it is considered that it is desirable not only to provide visibility for drivers but also consideration for the landscape of a circumference and environment. This paper, therefore, examined influences of a method for coloring on its visibility and landscape. We focus on painted color (blue, colcothar and green), width of bicycle lanes (1.0m, 1.5m and 2.0m), painted area of bicycle lanes (entire, both ends and one end), and interval of arrows on bicycle lanes (20m, 40m and none), and the influences of these on visibility and landscape have been examined by a driving simulator and a questionnaire survey.

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  • Suguru WATANABE, Masami YANAGIHARA, Hiroyuki ONEYAMA
    2018 Volume 4 Issue 1 Pages A_88-A_96
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    As one countermeasure for traffic congestion in the sag section, for the purpose of promoting suppression of speed reduction and early recovery of traffic jams, "the moving light guide system" is set up on expressways all over Japan. However, regarding the moving light guide system, there are not many studies on light emission conditions to increase the effect of increasing traffic capacity during congestion. About the moving light guide system, we conducted a comparative experiment of driving behavior using a driving simulator by changing the lighting condition, light emitter shape and brightness of the light emitter. The purpose of this experiment is to obtain knowledge about the light emission conditions for further improving the effect of increasing the traffic capacity by the moving light guide system. As a result, it was confirmed that the moving light guide system clearly had the effect of increasing the traffic capacity. Furthermore, it was suggested about the effect difference of changing the shape and brightness of the light emitter.

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  • Yuya TABEI, Teppei OSADA, Nobuaki OHMORI
    2018 Volume 4 Issue 1 Pages A_97-A_105
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    In many Japanese cities, congestions caused by large-scale retail stores are big problems. In order to solve this problem for them, we conducted a research on traffic impact assessment focusing on a method of calculation for traffic of large-scale retail stores from various directions. At present, many large-scale retail stores use a circular trading area to estimate the traffic volume. In this research, it was found that the sizes of the circular catchment areas were uneven by the stores, and there were low correlations with the sizes of the stores. Furthermore, we succeeded in reducing the errors in estimations by using the catchment area based on travel times for calculation of the number of customers by directions and the frequencies of their visits depending on the distance. Even in the case of using a circular catchment area, we succeeded in reducing the errors in estimations by matching the sizes of the trade areas to the sizes of the stores. From these results, we also identified the relationship between the sizes of the stores and the sizes of the trade areas.

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  • Hirotoshi SHIRAYANAGI, Shun TAJI, Takahiro TSUBOTA, Shinya KURAUCHI, T ...
    2018 Volume 4 Issue 1 Pages A_106-A_112
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    This study investigates the relationship between driving experience and generalization of driver's stopping behavior. Previous research has suggested that an acquired behavior is triggered by positive reinforcement, and the same behavior is replicated by the same trigger in any situations once it is generalized. Driving behavior is a type of acquired behaviors, and therefore it is possible that a procedure in driving is generalized by accumulating driving experience. This study aims to relate the generalization of driver's stopping behavior to the driver's driving experience by comparing the stopping behavior in real space and virtual space presented by a driving simulator. The results showed that drivers with longer driving experience performed stopping behavior based on the same positive reinforcement regardless of the situations: real space or virtual space, which suggests that their stopping behavior is generalized. On the other hand, drivers with shorter driving experience did not exhibit the generalization in their behavior.

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  • Seiji HASHIMOTO, Yusuke TSUNEFUJI
    2018 Volume 4 Issue 1 Pages A_113-A_119
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    Residents in areas where bus routes have been abolished has a major challenge that it is difficult to have the opportunity of movement if private cars can not be used. As one of the countermeasures, there are cases where the local residents themselves are the administrators themselves to have community based public transport, and there are merits such as cost savings, fine-tuning of operations, and improvement of local community vitality, so introduction and operation continuation is done throughout the country. In this research, we focus on the "consciousness of the supporting side" by residents who do not normally use it, and we aim to know that in the area where the local residents mainly operate community based public transport, how they are related to the satisfaction level of the residents' living, eventually the sense of subjective well-being. As a result, " consciousness of the supporting side " is related to subjective well-being, indicating the possibility of giving positive influence.

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  • Keisuke MATSUDA, Masami YANAGIHARA, Hiroyuki ONEYAMA
    2018 Volume 4 Issue 1 Pages A_120-A_128
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    There are studies focusing on the intersection structure and the presentation pattern concerning the safety and efficiency of the intersection, but there are few studies focused on the position of the signal lamp, few knowledge such as the difference in driving behavior due to the difference in lamp position. In this study, in order to obtain useful knowledge about differences in driving behavior, behavior judgment and driver's feeling due to the difference in position of the signal lamp, we analyzed the driving behavior date obtained by the DS experiment about the influence on driver’s behavior and judgment by the position of the signal lamp. The position of the signal lamp was experimented in the far-side of the intersection, mainly adopted in Japan and near-side of the intersection, mainly adopted in many foreign countries such as Germany. Based on the experimental results, differences were found in behavior judgment of passing and stopping, and reaction time at stop and start.

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  • Hiroki TAKEI, Makoto OKUMURA
    2018 Volume 4 Issue 1 Pages A_129-A_137
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    Evacuation using a car got allowed in Japan after the 2011 Great East Japan Earthquake, if it is really needed for the community. Excessive car usage may increase the risk being caught by tsunami due to the traffic jam and queue in road, as well as traffic accident risk due to collisions with pedestrians. This study proposes a cell-based tsunami evacuation model to minimize the risk of being caught by tsunami, considering vehicle-pedestrian mixture and resulted traffic accident risk. An illustrative analysis for a real scale municipality facing to the Pacific Coast in Japan shows that the optimal vehicle usage rate is around 20% with usage of alternate routes other than the shortest route of each car, having negative effects to increase of traffic accident. We show that traffic safety measures must be considered based on the time and location of high traffic accident risk, calculated by the proposed model.

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  • Daiki NISHIHARA, Hiroshi TATSUMI, Syuji YOSHIKI, Ryota MORI, Kotaro HA ...
    2018 Volume 4 Issue 1 Pages A_138-A_146
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    Guideline for creation of safety and comfort bicycle environment” established in 2012 recommends that an apron of road shoulder is maintained as a space saving type when necessary. For this study, cycling experiments were conducted on road shoulders of different types to examine the impact apron width on the consciousness and their cycling behavior. A hearing survey was carried out, and it was found that a sense of security about cycling was influenced by apron width on only 1.15-meter-wide road shoulders and cyclists were especially conscious on bicycle lane and apron width. Next, the impact of these on cycling behavior was examined. Any road shoulder, cyclists were able to use the bicycle space wider on space saving type sections than Standard type ones. In addition, they were able to avoid toward sidewalk side on space saving type sections when they were overtaken by several vehicles on 1.3-meter-wide and 1.5-meter-wide road shoulders.

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  • Yu HASEGAWA, Miho IRYO
    2018 Volume 4 Issue 1 Pages A_147-A_153
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    This paper validates reproducibility of a virtual reality simulation and reveals its feature, in order to investigate feasibility of virtual reality experiments for evaluation of safety and comfortability against personal mobility vehicles from the point of pedestrian view. 32 participants were gathered and played a pedestrian role. They experienced scenarios in which a personal mobility vehicle approached them in both virtual and real spaces. In each scenario, they gave their feedback of the perception against the approaching personal mobility vehicle including the spatial perception of distance and the subjective perception of safety and comfortability by questionnaire method. From a comparison of the questionnaire results of virtual space and real space, this paper clarified that virtual reality simulations are valid in terms of spatial perception when personal mobility vehicles approach from the front and the side of participants. It also revealed that the simulations are feasible when they approach from the front and behind regarding subjective perception.

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  • Yasutaka SHIMODA, Akinori MORIMOTO
    2018 Volume 4 Issue 1 Pages A_154-A_160
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    In Japan, the number of traffic accidents has been reducing for many years, and it can be assumed that various factors, such as law amendment, road construction, and traffic safety education, have contributed it. However, the decrease tendency of traffic death accidents is becoming smaller these few years. To achieve the target of ‘The 10th Fundamental Traffic Safety Program’ that is to make the number of fatalities within 24 hours below 2,500 people per year, efforts to contribute to further reduction of traffic accidents are necessary. Among the various efforts that may lead to achieve this goal, traffic enforcement is listed as one of the priority measures in ‘The 10th Fundamental Traffic Safety Program.’ Based on these backgrounds, this research has revealed the traffic accident suppression effect by showing traffic enforcement activity to help reduce traffic accidents in our country. As a result, it was found out that showing vigilance activity has the effect of suppressing frequent occurrence of traffic accidents.

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  • Takafumi KONO, Akinori MORIMOTO
    2018 Volume 4 Issue 1 Pages A_161-A_168
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    One of the representative road safety measures in Japan is traffic enforcement, and to implement in accordance with the actual condition, traffic execution plans have been formulated at each police station since 2011. These plans are conducted in the PDCA cycle, and the actual traffic enforcement is carried out based on the plans. However, there have been no studies which grasp the actual condition and compare regions of these Plans. Therefore, this study attempts to quantitatively organize the components and characteristic of the traffic execution plans of 5 stations in Hokkaido by using text analysis. As a result, the traffic execution plans were able to be classified into 11 constituents, and it was found that the effect of suppressing traffic accidents is expected also for countermeasures not focusing on traffic violation arrest. Also, co-occurrence relation and implementation focus in the plans, there were both similarities and differences between each police stations, and regional characteristics and road environment were cited as a factor.

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  • Akira ANDO, Keonhee MIN
    2018 Volume 4 Issue 1 Pages A_169-A_176
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    In this research, from the viewpoint of improving traffic safety policies, we focus on clarifying the characteristics of dangerous driving events (stop sign violation, ignoring traffic light, pedestrian disturbance, excessive speed etc.) which are thought to be closely related to traffic accidents. Conventional studies on traffic safety focused mainly on improvement of road structure etc. and aimed at extraction of dangerous places or spots from probe data, meanwhile this research focuses on dangerous driving behaviors which are initial but hidden cause of traffic accident. In addition, analysis of whole set of data which includes both of Video and GPS data during whole travel hours stored in drive recorders of 175 participants, which is unprecedented. As a result, it was shown that the dangerous driving has a certain occurrence tendency, which is attributed to the individual characteristics of the driver, the driving place, and the driving hours. The results of this research can be expected to contribute to effective driving safety enlightenment campaigns for reducing traffic accidents.

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  • Yo-hei WATARI, Yoshiyasu YANAGISAWA, Naoki TODOROKI, Noriyoshi NARISAW ...
    2018 Volume 4 Issue 1 Pages A_177-A_186
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    In response to the declining birthrate and aging of the population and the declining population in the future, there are many local cities that promote the transition to intensive urban structure aiming at compactification of cities, mainly at transportation bases such as stations. In the city structure in Nagano city, the policy to make it compact by centering on transportation stations such as stations is shown. In implementing compact of urban areas based on location optimization planning, it is necessary to clarify the distribution situation of urban function facilities and the movement ranges of visitors centering on stations, centering on the stations as the hub. Therefore, we clarify the influence of each facility distribution on the trips in the transport hub considering the distribution of urban function facilities centering on the railway station in Nagano city and the migration behavior of visitors. Furthermore, by clarifying the number of trips between hubs and actual situation of trip purpose, it aims to clarify the actual situation of movement to evaluate the consolidation of intensive urban structure centered on the transport hub.

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  • Hikaru KOSAKADA, Masahiro TADA, Masaya OKADA, Kazumi RENGE
    2018 Volume 4 Issue 1 Pages A_187-A_195
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    In this study, we have developed a real-time safety driving advice system based on automated method of driver’s skill. Our system measures drivers scanning behavior with head motion by wearable sensors and detects his/her risky behavior (e.g. a driver enters a blind inter section with excessive speed without scanning around) from the view point of active safety. By evaluating measured driving behavior based on driving instructors’ safety driving knowledge, our system provides safety driving advice in real time. In Japan, elderly drivers aged over 70 years are required to take the mandatory driving retraining course when renewing their driver’s licenses. In this paper, we experimentally take our system into the retraining course for elderly drivers and verified the effectiveness of our system. Through experiments with 72 subjects (36 subjects were given safety driving advice in real time, and the others were not), we confirmed that our system can improve elderly drivers’ behavior by providing safety driving advice in real time.

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  • Shoichi HIRAI, Jian XING, Shin-ichiro KAI, Ryota HORIGUCHI, Nobuhiro U ...
    2018 Volume 4 Issue 1 Pages A_196-A_205
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    The objective of the paper is to construct rest area choice model and rest time model during a trip on inter-urban expressways by using ETC 2.0 probe data and attribute data of rest areas. First, principal component analysis is conducted with regard to the attributes of rest area size and shop types that are assumed to affect driver's resting behavior during their trips, and as a result, three components are selected to feature rest areas. Secondly, as a binomial choice problem of pass or drop-by when a driver comes to a rest area, the paper constructs several disaggregate logit models with independent variables of trip contextual information and three components of rest area attribute characteristic, and also estimates model parameters with high likelihood ratio. It is found with the identified models that time period dummy variable tends to distort the model structure and consequently reduces the model accuracy. Finally, a rest time model is formulated as a composite Gamma distribution of short rest time and long rest time in consideration of the existence of dining facilities and time period that may affect the rest time.

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  • Yuki SAWAMURA, Yasuhiro SHIOMI, Takashi YAMAMOTO, Kouzi YAMAMOTO
    2018 Volume 4 Issue 1 Pages A_206-A_215
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    In recent years, Variable Speed Limit (VSL) is adopted as one of the active traffic management system in some developed countries, and VSL works significantly to mitigate congestion and prevent traffic accidents. However, in Japan, the effect of VSL has not been revealed yet. In order to position the VSL as a menu of dynamic traffic management that contributes to easing mitigate congestion and reducing accidents, it is considered that drivers need to recognize the speed control sign include the VSL signs, and they also obey the speed limit. Therefore, in this research, we aim to clarify the potential effect of the VSL signs in Japan and the psychological factor which determines the driver’s behavior to the speed limit on the expressway by using the questionnaire survey. As a result, driver's degree of recognition of VSL signs and speed compliance rate on expressway were shown quantitatively. In addition, it is suggested that the three psychological factor, “selfish belief”, ”normative conscious”, and ”attitude to information”, may have an effect on consciousness on speed limit compliance.

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  • Takahiro TSUBOTA, Toshio YOSHII, Hiro HARADA, Hiroaki JINNO
    2018 Volume 4 Issue 1 Pages A_216-A_222
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    This study aims to develop an average travel speed estimation model for signalised arterials based on the relationship between flow (Q) and speed (V). Such relationship, or the QV relationship, describes the travel speed at given flow levels, which plays crucial role in designing traffic management schemes to evaluate the traffic performance after devising the policies. On the other hand, in the state of the practice, the QV relationship of signalised arterials only relates the daily traffic volume and daily average travel speed, which is unable to capture the dynamic changes in traffic, and therefore, hinders the proper evaluation of traffic performance after the policies. This study developed the methodology to estimate the QV relationship of signalised arterials using traffic data aggregated in smaller time intervals (e.g., 15 minutes). The proposed QV relationship relates the space-mean flow and speed along a corridor by utilising multiple detectors. The travel speed estimation model was developed based on a multiple linear regression model, which defined the average travel speed using the space-mean flow, road geometry and time of day. The model exhibited sound accuracy with R2 of 0.77, and revealed the impact of road geometry and temporal difference on travel speed.

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  • Gen HAYAUCHI, Fumihiko NAKAMURA, Shinji TANAKA, Ryo ARIYOSHI, Shino M ...
    2018 Volume 4 Issue 1 Pages A_223-A_228
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    Recently, ropeways have been introduced to world's several cities as an urban transportation system and are expected to play a role as a new urban transportation mode. This study aims to investigate roles of ropeways quantitively from the viewpoints of travel time based on the theory of transportation gap. First, the existence of the "gaps", the distance whose demand is not covered sufficiently by existing modes in terms of travel time, was revealed by comparing travel time of existing transportation modes with acceptable travel time by using Person Trip Data in Tokyo metropolitan area. Secondly, maximum acceptable travel distance of ropeways was revealed to be from 0.3km to 4.2km by comparing travel time of world's in-service urban ropeways with acceptable travel time. Finally, combining results of analyses of existing transportation modes and ropeways, it was found that one of the "gaps" which is from approximately 2km to 4km, can be covered by ropeways.

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  • Hiroki TOYAMA, Aya KOJIMA, Teruhiko TUZUKI, Yasusuke NAGAIZUMI, Kouic ...
    2018 Volume 4 Issue 1 Pages A_229-A_237
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    In 2016 Government of Japan issued a guideline for physical devises in community areas. In this guideline, the detailed form of humps placed in uninterrupted road sections is shown, however, the shape of humps implemented in intersections, especially its splays, is not described specifically. In this study, the authors focused on a hump placed in an intersection that does not have sidewalks and investigated its shape on a view point of universal design. The authors verified the gradient of splays a hump and implemented a prototype in Saitama University. After the pretest, social experiment was conducted in a residential area in Saitama City. Using a wheel chair, subjects tended to feel difficulty when they passed on a part splay of the hump which gave cross-section gradient more than 2%. The results of traffic surveys revealed that the hump made passing cars slow and it did not produce unacceptable noise and vibration.

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  • Katsuhiro IIDA, Yasuaki WADASAKI, Masahiro TADA, Tomohiro CHIKUGO, Si ...
    2018 Volume 4 Issue 1 Pages A_238-A_245
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    Recently, automated driving technology has been developed in order to reduce traffic accidents and to mitigate traffic congestions. In terms of road and traffic administration, however, some problems remain to be solved. For example, it is concerned that traffic safety and efficiency will be affected by the penetration of automated vehicles to traffic flow. In this paper, adaptive cruise control (ACC), which is a principal system of automated driving technology, was focused. Then, the traffic flows which consist of both ACC vehicles and non- ACC vehicles, were generated and its safety and efficiency were investigated through an indoor driving experiment using a driving simulator. As a result, it was observed that traffic flow rate was improved especially in the section with sag or sharp curve as the proportion of ACC vehicles increased. In addition, it was also revealed that the potential collision risk was alleviated by the introduction of ACC vehicles.

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  • Shinji ODAKA, Toshio YOSHII, Nobuto KANBE
    2018 Volume 4 Issue 1 Pages A_246-A_251
    Published: February 01, 2018
    Released: February 01, 2018
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    Implement traffic management which encourages traffic shift from a high risk route to a low risk route in the view of spatially and temporally with understanding the probability of accidents in the road network (referred to as "accident risk"). It can reduce the number of traffic accidents. However, accident risk in expressways and arterial roads can be calculated from the problem of acquiring traffic flow data by sensors, On the other hand, accident risk calculation on specific residential roads was difficult. In this research, using the ETC 2.0 data which is becoming popular in recent years, we propose a method to estimate the distance that ETC2.0 vehicles running of residential roads. Furthermore, accident risk of residential roads is analyzed based on the distance that ETC2.0 vehicles running estimated by the same method for actual road network in Matsuyama metropolitan area. As a result, the accident risk becomes high in the narrow road width road.

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  • Koji SUZUKI, Akari KATO, Yoshiki YAMAGUCHI
    2018 Volume 4 Issue 1 Pages A_252-A_257
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    This study revealed pedestrian safety, ease of crossing and mental load at two-stage crosswalk on basic section by field survey. The field survey is consisted not only the observation survey by video camera recorders but also walk experiment with heart rate meter at 4 sites. First we analyzed the heartbeat interval data and made a comparison between the mental load of the edge of crosswalk and that of the median refuge island. As a result, it is found that the mental load for waiting at the refuge island is not so high as compared to that for waiting at the edge of crosswalk. Second we analyzed the vehicles’ yielding movements for crossing pedestrian near at crosswalk. It is shown that the proportion of yielding behavior at two-stage crosswalk is higher than that of normal crosswalk. Furthermore, we conducted statistical analyses for the yielding behaviors. It is revealed that the proportion of yielding behavior is high at near-side of two-stage crosswalk and in case of the wider median refuge island. On the other hand, the higher approach speed is, the lower proportion of yielding behavior is.

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  • Hiroki GOTO, Toshiyuki NAKAMURA, Nobuhiro UNO
    2018 Volume 4 Issue 1 Pages A_258-A_264
    Published: February 01, 2018
    Released: February 01, 2018
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    Urban expressway is the aorta that supports the traffic of metropolitan area in Japan. But many accidents are still occurring due to complicated road linearity. So far various safety measures have been taken, but the effect is not necessarily permanent. Further it is assumed that there is a possibility of diminishing. Therefore, in this research, we aimed to grasp the long-term trend of the effect of traffic safety measures implemented in the past. We analyzed the anti-slip measure which is the longest implementation extension and is a representative countermeasure. Focusing on the planar linear shape of the countermeasure part, it was recognized that the countermeasure effect diminishes after a long period in the sharp curve section with a curved line radius of less than 200 m, and in other sections, it was suggested that the countermeasure effect will continue. Based on these findings, it is possible to apply additional measures before the effect is reduced in the future, and it is expected to contribute to the prevention of accidents.

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  • Shotaro KAWABUCHI, Shoki IIDA, Naoyuki NISHIKAWA, Shun FUJII, Tomoyuki ...
    2018 Volume 4 Issue 1 Pages A_265-A_273
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    Risk models by some traffic accident types with independent variables of geometric structures at 17 adjacent signalized intersections were identified using robust regression on Japan’s national Route 2 in Fukuyama City, Hiroshima Prefecture. A reduced size intersection using traffic inlands was excluded as an outlier due to its exceptionally low risk of rear end collision. Running trajectories of vehicles were estimated at every 1/30 second interval based on video observation data for the above outlier intersection and another intersection that is projected to be reduced in size. In addition, the running behavior of vehicles at the two intersections was analytically compared with accident risks. As a result, indexes of safety were found to be stable, despite relatively higher approaching speeds, at the reduced size intersection than at the standard size intersection. Left turn vehicles were found to maintain the lowest speeds when passing through a zebra crossing at the exit of the reduced size intersection.

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  • Kuniaki SASAKI, Masaya TOHYAMA, Akane SAWADA, Satoshi KUREBAYASHI
    2018 Volume 4 Issue 1 Pages A_274-A_279
    Published: February 01, 2018
    Released: February 01, 2018
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    This study focused on a kind of stock effect of the community road. The stock effects of the road are mainly discussed on the trunk roads and highways, but even on the community level road, there could be multi-effects on the life, economy and health of the inhabitants. The purpose of this study is to find out those effects on the residents'life. The process we adopted is the measurement of the road environment of the community and the proposition of the indices made from them, that implies the walkability and drivability. Then we estimated multilevel logistic regression model using the questionnaire survey of the residents' health condition and physical activities as the objective variable, while we used the proposed indices as the explanatory variable. The results of the model indicated the significance of the relationship between the indices and the residents' physical activities. We concluded the community roads have significant stock effects on the residents' physical activity.

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  • Haruka UNO, Yuyang ZHANG, Seiji HASHIMOTO
    2018 Volume 4 Issue 1 Pages A_280-A_285
    Published: February 01, 2018
    Released: February 01, 2018
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    The number of occurrences of traffic accidents in Japan has decreased, but in recent years the rate of decrease has been decreasing, and traffic safety measures for automobiles are still necessary. In response to these, implementation of various traffic safety measures and introduction of automatic braking system are progressing in Japan, and many studies have focused on driver's consciousness. In this research, we not only grasp the driver's consciousness, but also the difference of driving experience, personal characteristics, safety awareness by "Social Capital". Because of classifying respondents according to the tendency of driving consciousness, it was classified into four clusters "safe driving tendency", "speed-oriented type driving tendency", "pedestrian / bicycle gaze type driving tendency", and "dangerous driving tendency". When analyzing the factors of driving tendency, it became clear that factors such as sex, number of near unsafe incidents and social capital greatly affected.

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  • Mitsuaki OBARA, Takehiro KASHIYAMA, Yoshihide SEKIMOTO, Hiroshi OMATA
    2018 Volume 4 Issue 1 Pages A_286-A_293
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    As more and more attention is layed on the assets that the public sector holed, public-owned vehicles are expected to play important roles along with the development in technology. However, there is no accurate data of public-owned vehicles in local government units. Therefore, the current status of public vehicle use is not yet grasped in the first place. In this research, all vehicle records of Kakogawa City and Fujisawa City in 2016 are analyzed. For example, link coverage rate by the public-owned car is calculated. Also, a system of optimize vehicle utilization is devised and evaluated. The findings are that public-owned vehicles can fully play the role as probe cars for daily inspection of public roads, and the optimization system shows that it is possible to perform business with 40 vehicles that was performed with 117 vehicles in actually. The possibility of reducing possession of public-owned vehicles by optimization is high.

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  • Masahiro OHTANI, Masahiro TADA, Masaya OKADA
    2018 Volume 4 Issue 1 Pages A_294-A_301
    Published: February 01, 2018
    Released: February 01, 2018
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    In Japan, since bus service is one of the most important transportation infrastructure especially in regional cities, traffic accidents by bus make large impact to our daily life. However, the number of bus accidents is still at a generally high level. In this study, we let 23 bus drivers (16 newly-employed bus drivers in training, 7 bus instructors) drive on public roads and measure their gaze behavior in traffic scenes frequently occurred in a daily service (e.g. departing from/stopping at bus stop, turning at busy intersections). By comparing measured data of drivers in training and those of instructors, we investigate in what kind of traffic conditions bus drivers behave riskily. As a result of our analysis, we found that drivers in training performed significantly less checking behavior than instructors while departing from bus stop or driving narrow residential streets where driver should simultaneously pay attention to multiple mirrors and traffics around to prevent in-vehicle/inter-vehicle accidents.

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  • Takeshi SHIBUKAWA, Shin YAMASHITA, Akinori MORIMOTO
    2018 Volume 4 Issue 1 Pages A_302-A_309
    Published: February 01, 2018
    Released: February 01, 2018
    JOURNALS FREE ACCESS

    As global environmental issues are pointed out, Japan's carbon dioxide emission remains to be one of the top in the world, and thus transformation to an environmentally friendly city is sought after in the field of transportation. For this purpose, appropriate estimation of environmental load due to traffic is crucial. However, the Person Trips survey data that has been used as the basic data of this estimation has not been fully grasped due to fiscal constraints and other factors. Meanwhile, utilization of the Population Flow data (the Mobile Spatial Dynamics) supplemented by the mobile telephone network is beginning to be considered, yet there are several concerns regarding its application such that transportation modes choice and trip purposes are being unknown. Based on this situation, this research examines the methodology to estimate traffic energy consumption as an indicator for the urban structural analysis through the usage of the Mobile Spatial Dynamics.

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