JSTE Journal of Traffic Engineering
Online ISSN : 2187-2929
ISSN-L : 2187-2929
Special issue: JSTE Journal of Traffic Engineering
Volume 7 , Issue 2
Showing 1-50 articles out of 51 articles from the selected issue
Special Edition A (Research Paper)
  • Satoshi TOI, Kaito MIHARA, Koji OOTSUKA, Yoshinao OEDA
    2021 Volume 7 Issue 2 Pages A_1-A_10
    Published: February 01, 2021
    Released: February 20, 2021
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    There are few studies on the methods to quantitatively estimate guidance effects by road information signs. Therefore, in previous researches, we have been developing a model in which the driver travels based on the guide sign information that appears on the planned route to the destination. In this research, we investigated the actual condition of the information use of the drivers, and constructed three types of driver’s inferring models which are “comprehensive type”, “sign dependent type” and “distance dependent type” considering the information use characteristic of the drivers. And based on the driving experiment using driving video image, the inferring models were verified on how they exactly estimate the rate of identification on the branch point by the drivers. And it was confirmed that the inferring model has sufficient accuracy with respect to two classifications of " branch in front or just branch point " and "pass the branch point".

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  • Akira HARAO, Jian XING, Fumiko SATO, Toshiyuki OKABE, Yuta TAKAHASHI, ...
    2021 Volume 7 Issue 2 Pages A_11-A_18
    Published: February 01, 2021
    Released: February 20, 2021
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    It is necessary to pursue countermeasures against wrong-way driving on expressways, because it may lead to serious accidents. We devised directional rumble strips which have different vehicle vibrations in the right way and in the wrong way. Based on the authors’ past research results using vehicle motion simulation and driving simulator, we carried out an actual vehicle running test using three types of groove shapes that varied in depth with different speed and vehicle type. The running test was composed of the measurement of vehicle vibration on the dashboard and questionnaire survey about the vibration degree for passengers after each running. Directivity of the proposed rumble strips for some vehicle types and running speeds was confirmed. The level of the vehicle vibration was found to be different with vehicle type, and some vehicle types showed larger vibration than other vehicle types even in the right way, which is a future issue.

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  • Kota MIYAUCHI, Kazuyuki TAKADA, Moeko SHINOHARA, Makoto FUJIU
    2021 Volume 7 Issue 2 Pages A_19-A_28
    Published: February 01, 2021
    Released: February 20, 2021
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    In recent years, with the development of intelligent transportation systems (ITS), the performance of automobiles has improved. On the other hand, in Japan, intentional dangerous driving by drivers and accidents by elderly drivers have become serious social problems. As a method to solve these problems, it is necessary to have a technology that detects the factors that lead to the occurrence of accidents and allows the vehicle to take appropriate control.

    In this study, we focus on driving behavior at intersections and propose a method to detect factors that lead to accidents appear. Applying the Long Short Term Memory Auto Encoder, we assumed that anomaly driving occurred when driving behavior that deviated from normal driving was observed and verified the effectiveness of the method. Comparing the proposed method with previous studies, it was confirmed that the detection accuracy was the highest and the detection timing could be detected relatively quickly.

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  • Katsuhiro IIDA, Masanori ASADA, Masahiro TADA, Hideo SAWADA
    2021 Volume 7 Issue 2 Pages A_29-A_37
    Published: February 01, 2021
    Released: February 20, 2021
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    The development of autonomous driving technology is pushed forward rapidly to improve the safety and smoothness of road traffic. In a previous study, focusing on adaptive cruise control (ACC) system, we simulated mixed-traffic flow consisting of ACC vehicles and non-ACC vehicles, and evaluated the safety and smoothness of the traffic flow and drivers’ behaviors. In the results of this study, it has been confirmed that the smoothness of traffic flow was improved with the increase of the mixture ratio of ACC vehicles, and that driver’s stress could be relieved by the ACC vehicles being mixed. This study assumes that a driver can become easily careless when the driver's stress is extremely reduced. Based on the assumption, the driver's viewpoint movement and reaction time was analyzed to evaluate the driver's carelessness. As a result, it has been confirmed that a driver can become possibly careless in the environment where many ACC vehicles are driven even when driving a non-ACC vehicle. It has also been confirmed that driving an ACC vehicle can cause a driver's arousal level to be lower, if not cause him or her to drive carelessly.

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  • Katsuhiro IIDA, Reo FUJIMOTO
    2021 Volume 7 Issue 2 Pages A_38-A_43
    Published: February 01, 2021
    Released: February 20, 2021
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    In case of level 3 autonomous car which has continuously spread now, a warning for driving relay is raised before the system is released and a driver is obliged to respond to it. Therefore, it is believed to be an important problem on security to understand the release conditions. In this study, clarification of the release conditions as described above was pursued by grasping how a state of traffic lane dividing lines had impacts on detection performance of lane departure warning system. Based on a driving experiment conducted on a test course equipped with traffic lane dividing lines that imitated a deteriorated state in a simulated manner, we measured detectability of the traffic lane dividing lines as well as luminance of the traffic lane dividing lines and the road surface. From results of the experiment data analysis, it has been suggested that difference in luminance between traffic lane dividing lines and road surface is a factor to affect detection performance which could be reduced when the difference in luminance falls down to a certain value or less in a case that the traffic lane dividing lines have deteriorated to some extent.

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  • Jun ITO, Noriyuki SAKAI, Kazushi SANO, Kiichiro HATOYAMA
    2021 Volume 7 Issue 2 Pages A_44-A_53
    Published: February 01, 2021
    Released: February 20, 2021
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    In this research, as one of the researches to promote various measures for traffic facilitation in winter, we analyzed influence of winter weather condition, especially snowfall, on value of travel time and calculated travel time-saving benefits. In this research, we adopted preference approach since distress and physical fatigue due to traffic congestion during snowfall may have influence on value of travel time. The case study was conducted in Niigata Prefecture, where most of the prefecture is designated as a special heavy snowfall area. The results confirm that the value of travel time is significantly higher in the winter period than in the non-winter period. The value of travel time in winter was used to calculate the travel time-saving benefits based on the cost-benefit analysis manual. The results show that even if the reduction in traffic volume during the winter period is subtracted, the travel time-saving benefits is greater when using the value of travel time in winter.

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  • Yoshitaka MOTODA, Seiji USAMI
    2021 Volume 7 Issue 2 Pages A_54-A_59
    Published: February 01, 2021
    Released: February 20, 2021
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    In this paper, a basic analysis of the walking rate of the 1000 mm width escalator passengers at railway stations had been carried out. Following results were obtained by observing eight escalators with different vertical rises at three subway stations in Tokyo. Walking rate was higher at down going escalator than up going escalator. The relation between walking rate and passenger volume was different at up going escalator and down going one. There was a significant correlation between passenger volume and walking rate at up going escalator, but not at down going escalator. There wasn’t a significant relation between walking rate and escalator vertical rise either at up going or down going escalator when a vertical rise was at least less than 20 m. Using the quantification method type II , significant parameters that affected walking rate were passenger’s cellphone using, passenger’s grasping handrail, passenger’s age generation and gender. Concerning gender, female walking rate was lower than male only at up going escalator.

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  • Naoki HATTORI, Nobuaki OHMORI, Teppei OSADA
    2021 Volume 7 Issue 2 Pages A_60-A_67
    Published: February 01, 2021
    Released: February 20, 2021
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    This study aims to examine the effectiveness of education for high-school and university students to keep the rules and improve manners on bicycle riding. We conducted an online questionnaire with providing information on safe bicycle riding and analyzed changes in attitude towards safe cycling. The questionnaire focused on the three major cycling behavior against traffic rules or manners: “cycling with an umbrella”, “cycling with smartphone” and “cycling on a shopping mall but not walking with bicycle”. To investigate the effects of psychological reactance, we divided the respondents into four groups and provided them with the four different types of information combining the two types of messages and two types of photos. It was found that behavioral intention on safe cycling increased for all the four groups of high-school students. However, for university students, their behavioral intention has increased for the only one group which was provided with the information of non-interference message and photo against the rule, and kept the level for one month. In addition, the frequency of cycling and the experience of traffic accidents affects the changes in their attitudes toward safe bicycle riding.

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  • Yasuhiro MIMURA, Keiichi HIGUCHI, Riku NAKAMURA, Ryo TOMURA, Shinji YO ...
    2021 Volume 7 Issue 2 Pages A_68-A_77
    Published: February 01, 2021
    Released: February 20, 2021
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    This study clarified the spatial cognitive characteristics of elderly drivers at non-signalized intersections, which have spatial characteristics that make them likely to be the at-fault drivers to encounter crossing collision accidents, through experiments using a head-mounted display (HMD). We asked 29 elderly people and 14 non-elderly people to watch 360-degree images from five different inflow sections at two non-signalized intersections under conditions close to actual driving. The results showed the following.

    (1) Compared to non-elderly people, elderly drivers have a shorter horizontal line-of-sight movement distance on non-priority roads "before stopping under the stop sign" and "when passing through an intersection after stopping".

    (2) In the above section, the spatial cognition of elderly drivers is generally centered.

    (3) At intersections where non-priority roads connect at acute / obtuse angles, the spatial awareness of elderly drivers is reduced.

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  • Shohei ISHIDA, Satoru KOBAYAKAWA, Hiroki KIKUCHI, Yuya TABEI
    2021 Volume 7 Issue 2 Pages A_78-A_85
    Published: February 01, 2021
    Released: February 20, 2021
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    The various countermeasures for serious traffic accidents are implemented at black spot intersections. However, the traffic accident data and near-miss data, which is used for considering traffic accident countermeasures, cannot grasp all occurrences of dangerous situations. For example, the signal phase at traffic accidents and/or near-miss events is recorded subjective data only. It is also difficult to analyze quantitatively using the number of accidents at a specific intersection only because the traffic accidents are an accidental event. Therefore, in this study, the occurrence of dangerous situations at the black spot intersection of right turn vehicles and crossing bicycles and pedestrians was analyzed using PET (Post Encroachment Time) indicator, a traffic conflict indicator for identifying dangerous events quantitatively. As a result, it was found that there was a hazardous risk for the right-turning vehicle in the vehicle group and pedestrians/bicyclists crossing alone after the green signal starts lately.

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  • Daisuke SHIMADA, Akinori MORIMOTO
    2021 Volume 7 Issue 2 Pages A_86-A_93
    Published: February 01, 2021
    Released: February 20, 2021
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    In recent years, the practical application of driver assistance technologies has been advancing in Japan, and it is expected that efforts toward the social implementation of autonomous driving systems will continue to intensify in the future. It is expected that the widespread use of autonomous vehicles will help to reduce traffic congestion and accidents. On the other hand, in the transitional period where autonomous vehicles and conventional vehicles coexist, traffic flow may be adversely affected by the difference in driving behavior of the vehicles. In this study, a traffic flow simulator was developed to simulate the mixed traffic flow, and the smoothness and safety of the traffic flow were quantitatively evaluated by changing the mixing rate of autonomous vehicles and the setting values of the driving behavior parameters. As a result, it was confirmed that the influence on the traffic flow differed greatly depending on the mixing rate of the autonomous vehicles and the driving behavior parameters.

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  • Nobuhiko MATSUMURA, Saki MOHRI, Nagahiro YOSHIDA
    2021 Volume 7 Issue 2 Pages A_94-A_101
    Published: February 01, 2021
    Released: February 20, 2021
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    Accidents caused by failing to observe safety at intersections make up a large portion of bicycle traffic accidents. As such, practical road safety education is compulsory for children. The present study investigated the application of brakes by parent cyclists in accordance with a principle of verbal communication (i.e., verbally communicating their ongoing process of checking and decision making), and the road safety outcomes on children achieved by means of parent child communication while riding on bicycles with two infant seats. Applying the principle of verbal communication was seen to raise the parent cyclists’ awareness of checking for safety, and there was a greater incidence of applying the brakes at intersections as a safety measure. Further, the children displayed a range of responses to their parents’ communications, and responded actively when prompted by their parents checking for safety and anticipating dangers and surrounding physical objects. This was seen to have implications for the children’s road safety education.

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  • Kunihiro ADACHI, Koji SUZUKI, Yuki OKADA, Hiroki ITO
    2021 Volume 7 Issue 2 Pages A_102-A_109
    Published: February 01, 2021
    Released: February 20, 2021
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    In this study, we conducted observation surveys at two unsignalized two-stage crosswalks and analyzed both the characteristics of pedestrians’ and cyclists’ crossing movements near/at two-stage crosswalks and the relationship between their jaywalking behaviors and the surrounding situations. Firstly, we indicated that jaywalking tends to occur in cases where it is possible to short-circuit by using their traffic line to the station or continuous intersection. Second, we found that company employees are more likely to cross illegally by examining the attributes of crossers. We also identified both differences in the conditions under which the elderly people and housewives were more likely to cross uncontrolled, and in the occurrence of jaywalking by pedestrians and cyclists. Furthermore, we clarified that jaywalking behaviors are subject to occur when the moving distance can be significantly reduced by jaywalking, and that it is also affected by the presence of surrounding pedestrians and cyclists by statistical analysis.

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  • Shizuha BABA, Ryo INOUE
    2021 Volume 7 Issue 2 Pages A_110-A_118
    Published: February 01, 2021
    Released: February 20, 2021
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    Deep learning has been attracting attention as a prediction method of traffic condition. Deep learning, which can automatically extract the relationships inherent in the data, has shown high performance for many types of prediction problems, and its usefulness for prediction of traffic condition has also been confirmed. However, most previous prediction methods using deep learning do not consider the relationships between multiple traffic variables and only consider location-based predictions. However, when considering traffic control for mitigating traffic congestion as an example of application of the prediction results, the prediction of traffic condition for a region, which is the unit of control implementation, are highly useful, rather than a point-based one. In this study, the LSTM, a deep learning model, was used to examine short-term predictions aimed at representing the relationship between multiple macroscopic traffic condition indices aggregated on a regional basis, and its performance was confirmed through application to the observed data of urban roads.

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  • Hirotoshi SHIRAYANAGI, Shingo HAYASHI, Shinya KURAUCHI, Toshio YOSHII
    2021 Volume 7 Issue 2 Pages A_119-A_125
    Published: February 01, 2021
    Released: February 20, 2021
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    Lateral viewing where the directions of the head and eyes are different and the change of the lateral viewing with time interferes with attentive visual search performance because visual attention resources are divided and coordinated into head and eye directions. In this study, we hypothesize that lateral viewing and the change of the viewing affects the duration required for visual perception of road space. Specifically, we focus on the lateral viewing of pedestrians when they cross a road and analyze the effect of the lateral viewing and the change of the viewing on the search time for a target stimulus in the road space by conducting a visual search task. The results showed that the longer the time required to search time for target stimulus in the road space, the greater the lateral viewing and the greater the change of the lateral viewing with time. The results supported the above hypothesis.

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  • Takato MIYAMURA, Shinji TANAKA, Fumihiko NAKAMURA, Ryo ARIYOSHI, Shino ...
    2021 Volume 7 Issue 2 Pages A_126-A_132
    Published: February 01, 2021
    Released: February 20, 2021
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    Traffic congestion continues to occur at many intersections in Japan, obstructing the smooth flow of traffic. On the other hand, in recent years, the long-term reduction of traffic capacity on expressways has been attracting attention, and this phenomenon may also apply to ordinary roads. In this study, we focus on the space clearance between queued vehicles at signalized intersections, and investigates whether or not the distance changes over time, and the effect of such changes on traffic flow.

    As a result, space clearance have been gradually increasing, especially since the 2000s, and the increase is about one meter greater than it was 30 years ago. The results of the study suggest that the increase in space clearance is not necessarily due to the type of vehicle, but rather to changes in driver behavior. It was also found that a one-meter increase in space clearance resulted in a 15% increase in the length of the queue at intersections.

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  • Mitsuhiro HATTORI, Hajime INAMURA, Takashi OGUCHI, Naohiko HIBINO, Shi ...
    2021 Volume 7 Issue 2 Pages A_133-A_141
    Published: February 01, 2021
    Released: February 20, 2021
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    Under the rainy weather, compared with the dry weather, driving condition is worsened by the extension of the braking distance and reducing visibility. In this research speed distributions are shown to contribute traffic safety and effective operation on the highway by using high spatiotemporal resolution radar network data called XRAIN. At the beginning, the advantage of using XRAIN is presented, compared XRAIN data with AMeDAS rain gauge data, on the highway by showing actual raining example on 10th of August 2015. By using XRAIN data and vehicle detector data on the Metropolitan Expressway #3 Shibuya line and #4 Shinjuku line, non-linear relation is found between operating speed on highway and precipitation intensity. The speed reduction in a lower precipitation intensity is higher than the speed reduction in a higher precipitation intensity. In addition, similar distributions are found in the corner section. However, as the curvature increases, its tendency becomes weaker.

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  • Takuro SATO, Satoru KOBAYAKAWA, Junya OYANAGI, Hiroki KIKUCHI, Yuya TA ...
    2021 Volume 7 Issue 2 Pages A_142-A_150
    Published: February 01, 2021
    Released: February 20, 2021
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    Bicycle-only spaces are being built to promote the passage of bicycles on the road. However, bicycle-only spaces have not been networked because the bicycle lane's width cannot be secured in the city area in many cases. On the other hand, bicycle-only spaces in a new town can be more comfortable to secure because the new town's road network is well designed systematically. Therefore, this study was surveyed to understand the road width composition for securing the bicycle-only spaces in Chiba Newtown. As the results, it was found that 30% of the road length had a width of 1.5m or more required as a bicycle lane in the new town. Additionally, many cyclists passed on the sidewalk without decreasing their speed, regardless of their attributes. In conclusion, it is essential to set the bicycle lane on the road, which can produce the space by the spatial reallocation of roadways without structural modification on the 70% of the road length.

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  • Kazuki SAKURAI, Satoru KOBAYAKAWA, Hiroki KIKUCHI, Yuya TABEI
    2021 Volume 7 Issue 2 Pages A_151-A_159
    Published: February 01, 2021
    Released: February 20, 2021
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    In Japan, the shortage of parking lots became apparent until the bubble economy period with high economic growth. Hence, it caused the problem of illegal parking on the streets. In order to solve this problem, off-street parking lots were promoted to develop around Japan. However, as the area occupied by parking lots in the city gradually increased, the utilization rate of off-street parking lots declined yearly. Hereafter, it is necessary to optimize and consolidate excess parking lots, but the impacts of consolidation of parking lots for users have not been analyzed in existing studies. Therefore, in this study, users' parking choice behavior was clarified first, and the impacts on the walking distance of parking users after parking lots consolidated were analyzed. As a result, it was found that combined plural parking lots can reduce the impacts on the walking distance of the parking users in consideration of the situation of the utilization of parking users of each parking lot.

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  • Yoichi SEKI, Satoru KOBAYAKAWA, Hiroki KIKUCHI
    2021 Volume 7 Issue 2 Pages A_160-A_166
    Published: February 01, 2021
    Released: February 20, 2021
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    The parking facilities for freight vehicles in the building are where freight cars with cargo handling can be used are insufficient. The handling of freight vehicles is important for conducting economic activities, but it is difficult to increase parking facilities for freight vehicles immediately in terms of land and cost. So that on-street parking facilities for freight vehicles must be operated to meet demand. The parking meter section and loading bay have been operated as on-street parking facilities. Currently, there are free on-street parking facilities for 20 minutes only for freight vehicle. However, it is not clear which type of parking facilities are optimal for actual situation of freight cars parking.

    This study, the surveys were conducted at several on-street parking facilities with different operations and analyzed the actual utilization of on-street parking facilities, parking meter section, loading bay, and free on-street parking facilities for freight vehicle for 20 minutes.

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  • Kosuke MIYAZAKI, Kojiro MATSUO
    2021 Volume 7 Issue 2 Pages A_167-A_174
    Published: February 01, 2021
    Released: February 20, 2021
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    In Japan the largest percentage of victims of pedestrian traffic accidents are 7 years old children. However, the reason for this has not been found. The purpose of this research is to investigate the relationship between travel behavior and traffic accidents in case studies of Kagawa and Aichi. Person Trip Survey and data on traffic accidents were used. No significant differences were found between the result in Kagawa and in Aichi. The accident rate of pedestrian traffic accidents was defined as the number of pedestrian traffic accidents divided by the length of time of walking trips. The length of time of walking trips was calculated by multiplying the number of walking trips by their length of time. It was found that the greatest number of walking trips and accidents was for children aged 5 to 7 years. The accident rate of a pedestrian accident decreased for children over 5 years old. From a gender analysis, there was a greater number of boys who had pedestrian accidents than girls, however, there was no difference in the relative number of walking trips of boys and girls.

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  • Satoshi HYODO, Hiroaki NISHIUCHI, Shinya KURAUCHI, Toshio YOSHII, Take ...
    2021 Volume 7 Issue 2 Pages A_175-A_184
    Published: February 01, 2021
    Released: February 20, 2021
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    Accident risk communications including accident risk information provision are important approaches to raise a driver’s awareness of road traffic safety from a long-term perspective by providing the information via various information media. The objective of the study is to investigate the effects of accident risk information provision using road information boards. A questionnaire survey for a total of 681 drivers living in Ehime and Niigata prefecture. In this study, we examined whether accident risk information provision using road information boards contributes to improving accident risk information attitudes and driver safety awareness by using structural equation model. The results shows that individual information acquisition factors make effects on accident risk information attitude and driver’s awareness of road traffic safety. It also shows that the accident risk information attitude such as understanding level, convincing level and the driver’s awareness of road traffic safety improved the driver who received the accident risk information on the road information boards.

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  • Masahiro ARAKI, Kiichiro HATOYAMA, Kazushi SANO, Takao TAKAHASHI
    2021 Volume 7 Issue 2 Pages A_185-A_192
    Published: February 01, 2021
    Released: February 20, 2021
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    Ride-sharing service is being considered as a new local public transit system in aging and depopulated rural areas in Japan. The purpose of this study is to consider the possibility of ride-sharing services in order to promote exchanges within community. In this study, we conducted a questionnaire survey in two depopulated areas in Niigata Prefecture, where the level of dependence on automobiles are different. The results suggest that the areas with low dependence on cars have high usage intentions of ride-share service, and that increasing the number of users may lead to the promotion of community exchange. On the other hand, in areas that are highly dependent on cars, although the intention to use the service was not high, it was suggested that the system could be used in combination with events to promote exchanges. However, how to recruit drivers is still a challenge in both regions and flexible countermeasures are necessary.

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  • Hironobu HASEGAWA, Yui CHIBA, Makoto KASAI, Tohru TAMURA
    2021 Volume 7 Issue 2 Pages A_193-A_200
    Published: February 01, 2021
    Released: February 20, 2021
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    KYT (hazard prediction training, K: kiken (hazard), Y: yochi (prediction), T: (training)) has been promoted in Japan as a part of traffic safety education. Most of the conventional KYT instructional materials are in third person perspective and mainly use illustrative images. On the other hand, recent developments in VR-related technologies have made it possible to create a first-person perspective, 360-degree, all-round video VR instructional material. However, VR instructional material’s effectiveness for traffic safety education has not yet been fully investigated. In this study, we first created VR and photographic instructional materials, then randomly assigned 10 students to VR instructional material, photographic instructional material and a control group, and evaluated the educational effects of the instructional materials in an experiment. The results of the pre- and post-survey questionnaires revealed that 1) the most appropriate teaching materials differed depending on the learning items, and 2) photographic materials were the most effective overall.

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  • Toshio YOSHII, Rui OKUHARA, Takahiro TSUBOTA
    2021 Volume 7 Issue 2 Pages A_201-A_206
    Published: February 01, 2021
    Released: February 20, 2021
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    Once a traffic accident causes a traffic obstruction, the effect extends not only to the vicinity of the accident site but also to the surrounding roads, resulting in the deterioration in road function on a network scale. The purpose of this study is to clarify that the effect of traffic accident on the deterioration in the network-wide traffic states, targeting the road network in Matsuyama City, Ehime Prefecture. Specifically, we analyze the change in shapes of the Macroscopic Fundamental Diagram ("MFD") after the occurrence of the accident. The trajectory data from the ETC2.0 probe vehicles is utilized in estimating the MFD. The network traffic states are represented by the network-wide traffic flow and density by ETC2.0 probes. Considering that the number of the equipped vehicles is increasing over time, these data is normalized by the monthly average of flow and density. As a result of estimating the MFD with and without the occurrence of traffic accidents, it was observed that there was a significant difference in the shape of the MFD due to the influence of the accident.

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  • Shota KAWAKAMI, Hiroshi SUGITA, Jun MORIO, Tetsuo MORITA
    2021 Volume 7 Issue 2 Pages A_207-A_215
    Published: February 01, 2021
    Released: February 20, 2021
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    In this study, we analyzed based on the Tokyo metropolitan area PT survey data, which has been continuously conducted five large-scale surveys every 10 years since 1968. Focusing on the "Life Stage (age)", we added the viewpoints of "Period" and "Generation". and considered changes in traffic behavior due to changes in socio-economic conditions and their factors. As a result, (1) the factors that increase the outing rate are more influenced by the "Generation" than the "Period", and (2) the factors that change the number of trips and the number of trips for commuting purposes are "age" and "Generation". (3) The factor of the change in the number of trips for private purposes is the influence of "age", and the influence of the temporal change by "Period" and "Generation" is small, (4) It was shown that the factors behind the change in the automobile usage rate are all influenced by the "Period", "age" and "Generation".

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  • Hiroaki TERADA, Masami YANAGIHARA, Hiroyuki ONEYAMA
    2021 Volume 7 Issue 2 Pages A_216-A_225
    Published: February 01, 2021
    Released: February 20, 2021
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    As a measure against traffic congestion in uphill and sag areas, a Moving Light Guide System that introduces light using LED light emitters that are continuously installed near the road shoulder has been introduced. In addition, although the development of autonomous vehicles has been progressing, it is thought that the mixed state of manual vehicles and autonomous vehicles will continue for several years, but no study has been conducted on the effect of the Moving Light Guide System under a mixture of manual and autonomous vehicles. The purpose of this study was to conduct a driving simulator experiment to understand the influence of the Moving Light Guide System on the traffic flow when the autonomous driving vehicles are mixed with manual ones. Our observations suggested that the Moving Light Guide System may be effective against manual vehicles, even in the presence of autonomous vehicles. Furthermore, we also analyzed the effects of individual characteristics on these and obtained findings.

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  • Yoshiaki TAKASAKI, Jun ITO, Kazushi SANO, Kiichiro HATOUYAMA
    2021 Volume 7 Issue 2 Pages A_226-A_235
    Published: February 01, 2021
    Released: February 20, 2021
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    This study focuses on the estimation of winter road surfaces, which are thought to have a significant effect on winter travel speed reduction, and clarifies the relationship between meteorological conditions, passing traffic and winter road surfaces. To this end, we observed weather conditions such as temperature and snowfall and traffic volume under various winter road surfaces during winter, analyzed the effects of weather conditions and passing traffic on winter road surfaces, and constructed a winter road surface estimation model. The results of the analysis show that there is a significant difference between the 15-hour cumulative snowfall and 10-minute and 7-hour cumulative traffic volumes as the road surface changes. A model for estimating three types of winter road surfaces (dry/wet, sherbet and compacted snow) was constructed with a high accuracy of 88.9%. It can be said that it is important to take traffic into parameter in the estimation of winter road surface, because the model that excludes traffic volume from the variables has a lower accuracy rate than the model that includes traffic volume.

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  • Taro MATSUMOTO, Hiroshi TATSUMI, Syuji YOSHIKI, Kayoko TSUTSUMI, Ryuta ...
    2021 Volume 7 Issue 2 Pages A_236-A_245
    Published: February 01, 2021
    Released: February 20, 2021
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    The bicycle environment has been improved on roadways in Japan as “A guideline for creating a safe and pleasant cycling environment” was enacted in 2012. In these cycling environments such as "Bicycle lane" and "Mixed-carriageway road", there is no physical separation between bicycles and vehicles, therefore it is necessary to pay more attention to the safety and smoothness of these cycling environments.

    We conducted biking experiments on various roads in 2019, and this study examined the influence of differences in width composition such as shoulder width and lane width on the vehicle behavior, road safety, and smoothness related to overtaking bicycles. The results show that the overtaking behavior differs depending on the width composition and that the composition effects on the vehicle speed, acceleration/deceleration, and avoidance distance. Based on the results, the safety and smoothness of each road are examined and integrated assessments of the safety and smoothness are conducted.

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  • Dang CHI ANH, Seiji HASHIMOTO
    2021 Volume 7 Issue 2 Pages A_246-A_253
    Published: February 01, 2021
    Released: February 20, 2021
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    In Hanoi, the capital city of Vietnam, motorcycles have been a popular means of transportation up to now, but as the level of income rises, the number of private vehicles tends to increase. In recent years, ride sharing has been introduced around the world and is attracting attention. Even in Hanoi, ride-sharing is a new means of transportation has been widely used. However, no research clarifies the effect of ride-sharing on the user's consciousness of owning a private car. The purpose of this study is to examine the change of the user's going-out behavior caused by the use of ride-sharing in Hanoi, and to grasp the user's consciousness of owning a private car. As a result, we conclude that ride-sharing improves the road environment and that there is an option to use motorcycles as the most accessible means of transportation instead of private cars and to use ride-sharing.

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  • Katsuhiro IIDA, Takaki ENDO, Masahiro TADA, Kazumi RENGE, Takashi YAMA ...
    2021 Volume 7 Issue 2 Pages A_254-A_262
    Published: February 01, 2021
    Released: February 20, 2021
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    Junction of the deep underground expressway which is currently under construction has a specific road structure that sharp curves and split or merge points are concentrated in a short section. It has been proved in a previous study that lack of guide information occurs. In addition, in a previous study, application of color-coordinated destination indicators as a guidance method not solely depending on traffic guide signs has been examined as a possible countermeasure against lack of guide information. Upon analysis of behaviors of vehicles and drivers obtained from indoor driving experiment using the driving simulator, effectiveness of the color-coordinated destination indicators as a countermeasure against the problems have been verified. In this study, color-coordinated destination indicators with traffic guide signs which layout are different from usual pattern has been estimated. And, to make the factor of the effectiveness clear, driver's recognition of visual information and judgement about a direction were analyzed.

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  • Jun SAKAMOTO, Ren IWAI, Nozomu NAGATA
    2021 Volume 7 Issue 2 Pages A_263-A_269
    Published: February 01, 2021
    Released: February 20, 2021
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    In the event of a large-scale earthquake in a densely built-up area of wood, road blockages due to the collapse of houses may hinder evacuation. Local governments are taking measures such as earthquake resistance for dwellings that may collapse. Still, they have not adequately responded due to the difficult financial situation in recent years.

    This study proposes a method for road blockage countermeasures during a large-scale earthquake. First, it calculates the possibility that residents can reach the evacuation site after the disaster using the census, digital road map, and each section's road blockage rate. Next, it considers the priority of road blockage measures that can efficiently increase the number of evacuees, taking into account local governments' financial constraints.

    The proposed method applied to the earthquake and fire priority countermeasure area in Kochi City as the case study area. As a result, it founded that it is efficient to take priority measures from the section where the number of people who can evacuate is the largest, the road blockage rate is high, or the frequently used route from each point to the evacuation site.

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  • Keitaro NAKAMURA, Akinori MORIMOTO
    2021 Volume 7 Issue 2 Pages A_270-A_279
    Published: February 01, 2021
    Released: February 20, 2021
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    In recent years, the improvement of public transportation services has been being examined by building a system that allows people to freely transfer between various types of public transportation. In this process, it is necessary to accurately identify the burden of transfer and reduce transfer resistance. In this study, we define transfer resistance as the burden caused by public transportation transfer, and conduct a quantitative analysis of how transfer resistance changes depending on the uncertainty of travel time, service frequency, and transportation behavior habits.

    This study examined changes in the intention to use public transportation, assuming the integration of information, reservations, and payments, and examined the effects of soft services on reducing transfer resistance. The results show that people who are not aware of public transportation services estimate low resistance to transfer because they do not usually use public transportation very often, and are unlikely to change their behavior toward public transportation when soft services are introduced.

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  • Yoshinao OEDA, Yusuke MORI, Satoshi TOI, Masayuki TAKADA, Ki-Hong KIM, ...
    2021 Volume 7 Issue 2 Pages A_280-A_288
    Published: February 01, 2021
    Released: February 20, 2021
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    This study observed vehicle horn usage on three intersections in Seoul, Korea, to investigate the relationship between horn use and traffic situations, such as traffic flow, composition of vehicle lanes, recording by video camera and writings. Then, we picked up one of those cases, ‘cutting in’, and tried to make a model for it, considering some causes related to vehicle speed, headway, traffic flow and arrangement of intersection. From the investigation, we classified horn usage into some types, ‘Cutting in’, ‘attention’, ‘pressure’, etc., and inferred a couple of causes of the horn use. We resulted that one of the causes is due to the way of using lane for right turn vehicles, another one is due to no match for lanes on inflow and outflow. For modeling, we could gain a statistically significant model including the factors related to vehicle drive, ‘velocity’, ‘distance between vehicles’ etc.

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  • Shuhei WADA, Sho TAKAHASHI, Naoyuki SHIRAISHI, Kazunori MUNEHIRO, Mino ...
    2021 Volume 7 Issue 2 Pages A_289-A_297
    Published: February 01, 2021
    Released: February 20, 2021
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    In the present study, objective is to reveal the driver's subjective risk perception when closing to a preceding vehicle in car-following situation under snowy or dry/wet road conditions. It was assumed that the driver uses the ACC to follow a preceding vehicle, and the preceding vehicle decelerated and approached. The results of the field experiment shown that the driver's subjective risk perception to the preceding vehicle was increased by ACC use. The models for estimating the driver's subjective risk perception to the preceding vehicle based on values of the 1/TTC and the 1/THW in the situation of preceding vehicle deceleration were delivered in each type of road conditions (Risk Feeling equation). From the Risk Feeling equation, the THW of the ACC, which corresponds to the conventional driving of the driver's subjective risk perception to the preceding vehicle, is shown in each road conditions. It was suggested that longer value of the THW is required to reduce driver's risk feeling when driving with ACC on snowy roads.

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  • Hirotaka OOKI, Masami YANAGIHARA, Hiroyuki ONEYAMA
    2021 Volume 7 Issue 2 Pages A_298-A_306
    Published: February 01, 2021
    Released: February 20, 2021
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    In this study, we analyzed the right-turn behavior in an intersection due to the difference in the installation positions of far and near signal lamps by experiments using a driving simulator. As a result of the experiments, there was no significant difference between far and near signal positions in the clearance time at the time of signal switching and the critical gap calculated from the gap selection behavior at the time of green light, and there was also no significant difference in the number of times the accelerator pedal was depressed. It was suggested that the signal position does not have a significant effect on the right turning behavior. On the other hand, in the analysis of the gaze point when waiting for a right turn after approaching, some subjects gazed at their front signal lamp most in far position, but in near position without the front signal light, they changed to gaze at the approaching vehicle in front. It was suggested that they are encouraging safe safety confirmation actions. It was also shown that the driver's passive driving characteristics affect these differences in gaze characteristics.

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  • Ryoko KOMATSUZAKI, Riku TAKEDA, Mamoru TANIGUCHI
    2021 Volume 7 Issue 2 Pages A_307-A_315
    Published: February 01, 2021
    Released: February 20, 2021
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    In recent years, the practical application of automated driving systems has been increasing in Japan. One benefit of automated driving systems is that they enable people to engage freely in activities while moving. However, accumulation of studies based on individuals' intentions is necessary because the intentions and subjective values of activities conducted while moving remain unknown. This study was conducted to examine automated driving effects in terms of the value of the activity. First, an original questionnaire survey was administered to ascertain the relation between individual attributes and intentions for in-vehicle activities after automated driving. Then, using the subjective activity time value of individuals, we calculated the value of travel time activity (VTTA) before and after the introduction of automated driving. Results revealed that the increase in VTTA nationwide is greater than the current value of time lost to congestion, and particularly, that the increase in non-work activity time during travel creates value.

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  • Rena KAWAI, Toru HAGIWARA, Sho TAKAHASHI, Yoshihiro TERAKURA, Yusuke O ...
    2021 Volume 7 Issue 2 Pages A_316-A_325
    Published: February 01, 2021
    Released: February 20, 2021
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    This study proposed speed adjustment delineators embedded in the center of the travel lane as a preliminary speed adjustment device for drivers who is operating a semi-automated vehicle to reduce conflicts with the merging vehicles on the expressway. We conducted experiments using a driving simulator with 46 participants, and the results of driving records and subjective evaluations showed that the information provided about speed adjustment delineators affected the driver’s avoidance behavior. The participants who were explained the intention of the speed adjustment delineators selected the appropriate speed adjustment to follow the instructions of the speed guide light at the upstream of the nose end in the merging section. This result led to merging behavior smoothly and reduced the subjective risk perceived by the drivers due to the merging vehicles. In addition, based on the acceleration and deceleration behavior of drivers when the speed guide lights were not turned on, the proper location of the speed adjustment delineators were revealed.

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  • Yo KAMIJO, Giancarlos PARADY, Kiyoshi TAKAMI
    2021 Volume 7 Issue 2 Pages A_326-A_335
    Published: February 01, 2021
    Released: February 20, 2021
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    Assuming that fully autonomous vehicles (AV) are widespread and shared AV (SAV) services exist, this study conducted a stated preference (SP) survey on private AV purchase and mode choices. Specifically, after acquiring revealed preference (RP) data on the use of privately owned vehicles and the most frequent trips, we designed and executed an SP survey of AV purchase and mode choice based on the RP data, and modeled behavioral intention using mixed logit models. Results from the the private AV purchase model suggests that financial aspects such as the cost of private AV, and individual psychological factors purchase intention, rather than the level of service of SAVs. The mode choice model results suggest that the value of time for the SAV service, in which users are expected to ride with many other users, is higher, suggesting a larger disutility from travel. Nevertheless, it became clear that disutility of travel time was smaller than that of non-motorized modes.

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  • Naoki TODOROKI, Yoshiyasu YANAGISAWA, Shinya IWASAKI, Yoshio NISHIKAWA ...
    2021 Volume 7 Issue 2 Pages A_336-A_345
    Published: February 01, 2021
    Released: February 20, 2021
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    In the central area of Nagano City, as one of the measures to revitalize the area, a pedestrian priority road project is being carried out with the aim of improving the mobility of pedestrians. In order to expand this project over a wider area in the future, it is necessary to aim for more efficient and effective maintenance. Therefore, in this study, we focused on the fact that visual information accounts for 83% of human perceptual information. By clarifying the relationship between the visual information such as the degree of attention to the walking space components and the focal length indicating the depth and the evaluation of the street, the factors that influence the evaluation of the street were clarified. As a result, it became clear that the degree of attention affects the evaluation of streets.

    In addition, it was shown that the occupancy rate and focal length of the walking space components may have an effect on the degree of attention, so there is a need to consider the depth of the street and the occupied area of the walking space components when developing streets.

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  • Ayuka WAKAHARA, Ryo ARIYOSHI, Fumihiko NAKAMURA, Gen HAYAUCHI, Shinji ...
    2021 Volume 7 Issue 2 Pages A_346-A_353
    Published: February 01, 2021
    Released: February 20, 2021
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    It is generally assumed that travel is a derived demand and that the time it takes is desirable to be short. However, travel time is sometimes accepted or deliberately reserved because it has meanings other than reaching a destination, and it is not clear under what conditions such recognitions are formed. The purpose of this study is to identify the factors that shape recognition of travel through a survey of intentions to shorten travel time. The aggregate analysis revealed that working on the day, the mode of transportation, the attributes of the accompanying person, and the level of satisfaction with the pre-movement activities made a difference in the recognition of travel. In addition, we evaluated each factor relatively by binary logit models describing whether the trip was a target for shortening or not. The results show that the presence of adult companions makes the largest contribution to acceptance for travel time, etc. These results provide new perspectives that should be considered in future transportation planning.

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  • Wenhao LI, Shinya KURAUCHI, Toshio YOSHII, Takahiro TSUBOTA
    2021 Volume 7 Issue 2 Pages A_354-A_361
    Published: February 01, 2021
    Released: February 20, 2021
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    In urban areas, many people drive into narrow roads without signal lights to avoid congestion on arterial roads. This is, however, a great danger to the residents as well as pedestrians and cyclists. To solve this "rat-run" problem, it is indispensable to develop the consciousness of rat-runners.

    To this end, we consider providing factual examples that the disadvantages of taking rat-tun outweigh the disadvantages. This study is based on Matsuyama City, Ehime Prefecture, While verifying the effect of shortening the required time by rat-running, it also analyzed the driving characteristics of vehicles taking rat-run. As a result, due to the waiting time when merging to the main road and the influence of the signal system control, the effect of shortening the time when taking a rat-run becomes smaller. Besides, while taking rat-run frequently, vehicle speed tends to increase significantly when there is more congestion.

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