Map matching (MM) is an important technology because it is used in the pre-processing of GNSS and GPS data. In this study, we compared the accuracy of route inference between MM based on the shortest path search, which is often used in practice in Japan, and MM based on the hidden Markov model (HMM), which has been studied in recent years. Specifically, we examined how different time resolutions (1, 5, 10, 20, 30, and 90 seconds) affect the accuracy of route inference for both MMs, using probe (GPS) data and true driving route information acquired in Matsuyama City, Ehime Prefecture. The results showed that the accuracy of both methods did not change significantly up to a time resolution of about 10 seconds, worsened at 20 seconds, and declined sharply at 90seconds. It was also confirmed that the accuracy of MM using HMM was generally higher than that of MM based on shortest path search.

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We investigated the characteristics of unsafe driving behaviors of community-dwelling older adults based on on-road assessments. Firstly, we developed detailed items of unsafe driving behaviors based on description data of “driving behavior diagnosis records” of approximately 9000 participants in a “training course for seniors.” We classified unsafe driving behaviors into several patterns through factor analysis and cluster analysis. Next, we analyzed correlations between seven clusters of unsafe driving behaviors and cognitive function test results, age, the frequency of driving, vehicles that participants used, and selection of training courses (AT or MT). The results indicated that older adults’ unsafe driving behaviors were not uniform according to age or the decline in cognitive functions. The empirical results of this study indicated that the following factors mutually interacted in forming and expressing unsafe driving behaviors: (a) normal aging, (b) lack of accurate driving knowledge, (c) cognitive and operational traits depending based on the regularly used motor vehicle, (d) difficulty in perceptual-motor coordination caused by the lower driving frequency, and (e) decline in memory and judgment assessed by cognitive function tests.

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Population decline has become a huge problem in Japan, as the population has been decreasing since 2010. One of the problems caused by population decline is the decrease in the number of passengers getting on and off the railway station. If the number of passengers decreases, it may be difficult for railway companies to maintain their services and the area around each station may decline. In this study, we consider what kind of land use is optimal to prevent the decrease in the number of passengers. As a result, we found that we could halt the decline to some extent by converting vacant land around each station into factories and low-rise housing. However, there are stations where the number of passengers cannot be halted even if all vacant land is converted to factories or low-rise buildings, and it is necessary to consider compact cities or urban shrinkage for these stations.

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Currently, transportation providers offer transportation passes that allow people to use their own railways and highways at fixed discounted prices. However, there is no common pass that allow the mutual use of transportation services provided by different providers. By offering a package product that integrates the mainline transportation from home to transportation hubs such as Shinkansen stations and airports, and the intra-regional transportation using expressway with rental cars, it is expected to expand the range of travel for tourists and increase tourist satisfaction. In this study, using Yamagata Prefecture as a case study, we analyzed the Expressway Pass data provided by NEXCO, conducted a basic tabulation of our original web survey, and developed a recursive logit model for extensive sightseeing. The results showed that very few people use Expressway Pass with rentalcars, the range of tourists’ travels is limited, and there are high needs for package products that integrate different modes of transportation. The recursive logit model for extensive sightseeing suggests the possibility of expanding the range of travels by offering package proucts.

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This study focuses on the travel behavior between the station, its periphery and the home as a small unit, town and village, of travel behavior for the urban transportation planning which the users need. The purpose of this study is to clarify the heterogeneity of mode choice and the relationship with its factors quantitatively, focusing on the habitual nature of individuals. It was conducted a structural equation modeling based on the mode choice frequency in order to clarify the factors of mode choice which cannot be understood by conventional methods assuming individuals as being homogeneous. It revealed that heterogeneity of walking choice is influenced by three factors, possibility of being picked up and dropped off, medium- to long-distance commuters and walking difficulty. While it revealed that heterogeneity of bus choice is influenced by the three factors of convenience of the bus, commuters in multi-person households and walking difficulty.

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This study analyzes the time series of cell phone location data, COVID-19 pandemic, in order to clarify the characteristics of behavioral changes in Kanazawa city. The model explains the time-series changes of the population staying in downtown Kanazawa by adding up several time-series patterns. The time series patterns include the following four: periodic changes from the whole period (including before pandemic), long-term trends of changes on the order of months, periods of emergency declarations and requests by the government, changes in the number of infected people. As a result, we find several characteristics. First, there is a clear negative correlation between the time trend of the average value of PCR-positive patients in Ishikawa Prefecture over the previous seven days and the number of visitors to the center of Kanazawa City. Second, although people’s sensitivity to the policy and the number of infected people decreases over time, the breakdown differs significantly between daytime and nighttime activities.

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In developing countries, owners of private vehicles tend to depend on their vehicles. This study aims to introduces the comparative analysis approach on private vehicle dependence, examining the gaps of trip rate (number of trips per person per day) by representative mode and trip characteristics by travel distance between car owners, motorcycle owners and non-owners in Asian Megacities. Through the comparative analysis, the characteristics of the mobility gap by the case study cities were observed as the indicators of the private vehicle dependence in terms of trip rate, trip length distribution and modal share for short distance trips are clarified, and paratransit may have important role to mitigate private vehicle dependency for the short distance trips in some cities.

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With the development of automatic driving technology, the controllability of vehicle behavior has increased, and clarifying the relationship between the vehicle behavior characteristics of individual vehicles and the turbulence of traffic flow may contribute to the realization of safe and smooth traffic flow. In the research on car-following behavior, which is the most basic behavior among vehicle behaviors, there have been many studies on the construction and estimation of car-following models, but few studies have estimated individual car-following models under various traffic conditions and clarified car-following behavior characteristics. In this study, we estimated individual ca-following models, showed the diversity of car-following behavior, and attempted to analyze the relationship between speed reduction and carfollowing behavior characteristics. The individual car-following model estimated using continuous vehicle trajectory data from image observation was typified by cluster analysis of estimated parameters. In addition, by extracting the vehicles that experienced a speed reduction event in a group of vehicles, we analyzed the relationship between the typology of the car-following behavior characteristics and speed reduction. The findings suggest that there is diversity in car-following behavior in both low-speed and high-speed environments, and that certain car-following behavior characteristics may contribute to or reduce speed reduction.

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This study aims to identify bus commuters’ intention to shift their travel mode to Yangon Circular Railway (YCR) after modernization by the upgrading project. A questionnaire survey to bus commuters was conducted, and the binary logit modeling analyzed the affecting factors on their intention of the modal shift. The result shows that the primary users of the upgraded YCR will be residents of the YCR station area who commute to their workplaces in YCR station areas. Then, the high-density development of residences and workplaces in the station area is highly expected to increase passengers of YCR. Those whose house and workplace is far from bus stops are also more likely to shift to YCR. So, the east and north sides of YCR lines, far from the bus route, will attract more passengers. Also, those who have longer commuting time and are caught in a long traffic jam have a stronger intention for the modal shift. Scenarios about YCR fare and shortened commuting time by the modal shift are developed, and the number of respondents who will shift to the YCR was calculated for each scenario. From the scenario analysis, reducing commuting time for 5-10 minutes greatly impacts the modal shift to the YCR, especially those who need to transfer between YCR and a bus. Then, some measures to reduce the transfer time are expected to encourage their modal shift. In addition, the YCR fare increase also has a significant impact on discouraging the modal shift, especially for those who need to transfer between the YCR and a bus. Therefore, introducing the integrated fare system between the bus and the train is recommended to encourage the modal shift.

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There are new road maintenance policies that prioritizes migration of pedestrians in center of cities. If this policy is to be implemented in rural cities, it is necessary to eliminate useless transit traffics in center of cities by arranging ring roads. However, if the shape of ring roads is deformed, the expected effect of ring roads may not be obtained. In this study, ring roads are classified according to patterns of elliptical shapes, and an evaluation model of bypass function is examined. So, we consider some basic conditions to eliminate useless transit traffics in center of cities by arranging ring roads. In addition, the authors suggest that the proposed method is possibly applied to evaluate performance of theta-shaped network with road passing through in center of cities as a future work.

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In order to achieve the greenhouse gas reduction target set by the Paris Agreement, it is essential to reduce the immense impact caused by the traffic environment. The introduction of low-carbon, next-generation transportation systems such as EV, LRT and autonomous vehicles has been attracting attention to reduce the environmental burden of transportation. In this study focused on low-carbon transportation systems and quantitatively evaluated the environmental improvement effects of next-generation transportation systems under the assumption of actual traffic flow in terms of traffic volume, EV penetration rate, and power supply composition ratio. In addition, the changes in transportation behavior caused by telework were incorporated into the big data of location information to clarify the environmental burden of transportation, and it was revealed that the environmental burden could be reduced to about half of the current level in 2050 when telework becomes widespread.

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Route buses, which are familiar with public transportation to people, should be easy to use for everyone. However many people often get on a bus with psychological resistance because basic information on bus usage is not very clearly announced. Therefore this paper aims to investigate the actual condition of information, especially bus route map, and examines between the bus route map deformation and understandability. First, we organized the characteristics and classified them into six groups. Second, evaluation experiments were conducted, factors related to understandability were clarified from the viewpoint of human behavior and consciousness when seeing the bus route map.

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In recent years, the effects of bicycles, such as reducing environmental load and improving health, have been attracting attention. Many cities around the world have introduced public bicycle sharing systems as a new means of transportation for cities. In general, bicycle sharing are not highly profitable. As this result, more than 60% of the bicycle sharing projects in Japan have local government support. However, less than 40% of the bicycle sharing projects conduct project evaluations to assess the adequacy of such support. Therefore, the purpose of this study is to obtain knowledge for the proper evaluation of public bicycle sharing projects through a comparison of cases of public bicycle sharing project evaluations in three cities, such as Okayama, London and Barcelona. As a result, it became clear that there are differences in evaluation methods between domestic and foreign cities. Specifically, KPIs have been set in foreign cities to evaluate the achievement of service levels set by the local government, but in domestic cities, KPIs have not been set and operators only need to do a self-evaluate.

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In rural areas, an increasing number of local governments are seeking to switch from fixed-route buses to taxis. However, the taxi business is facing a shortage of drivers due to the population decrease, so it is a concern whether the taxi business can meet the local demand. Therefore, it is effective in examining the feasibility of taxi business if the supply capacity of the business can be objectively grasped. In this study, we will construct a methodology for analyzing the supply capacity of taxi business in rural areas. Specifically, the model based on mixed integer programming is developed with adjusting the dispatch time when the customer makes a reservation considered. In addition, we apply this model in case study area to show not only the capacity but also the effect of the adjustment.

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In addition to advances in ICT, the COVID-19 pandemic has greatly accelerated the teleworking trend, and changed people's awareness towards public transport use. In particular, comfort during traveling and waiting is becoming more important, but the evaluation of comfort in transportation nodal and transfer spaces has not yet been conducted. This study conducted a questionnaire survey on users comfort in the nodal and transfer spaces, assuming hypothetical transfer routes. Based on the parameter estimation results of the transfer route selection model, we quantified the psychological resistance of the transfer and waiting environment in the nodal and transfer spaces. Then, the lingerability level of the spaces was evaluated.

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For the sustainable society, urban redevelopment is required to promote the urban vision of Compact City and improve QOL. This urban vision is supported by infrastructure development of slow mobility, like a walk. Moreover, walking environments are expected to play new roles for mitigating damages of natural and epidemic disasters. The aim of this study is to explore the relationship of QOL and walkability considering urban disaster resilience. First, it started with sorting out the main components of walkability, QOL, and natural and epidemic disasters. Next, the relationships were analyzed with text mining using data of academic literature. Finally, a questionnaire survey was carried out, and the relationships were analyzed with structural equation modeling.

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The location analysis based on mixed-integer programming has been actively discussed mainly in the fields of geography and operations research. In this study, we show Multi-objective optimization of “Michi-no-Eki” Locations in the greater Kanto area considering various users and functions. Especially we consider not only differences between local demand and flow demand, but also that between ordinary situation and disaster situation. By considering the trade-offs between different demand assumptions and evaluation criteria, we verify the suitability of the current locations and obtain a perspective for future policy decisions. As of 2021, there are nearly 270 “Michi-no-Eki” in the greater Kanto area, but their locations are spatially unbalanced. It is useful to compare the results with those obtained by our study.

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The purpose of this study is to confirm the improvement of the acceptability of the LRT by explaining the features of the LRT, to analyze the attributes and attitudes related to the acceptability of the LRT. In this study, a questionnaire survey was conducted in Maebashi City to understand the acceptability of the LRT based on two indicators: appropriateness and approval or disapproval. In this study, we conducted a questionnaire survey in Maebashi City to understand the acceptance of LRT. We also found that the LRT has a great deal of acceptance in Maebashi City, and that it is difficult to give a neutral answer as an explanatory effect. In addition, the number of people who own cars is related to the number of non-residents along the rail line. It was found that those who choose suburban areas with easy access to shopping centers, those who shop frequently, and those who are more budget-conscious are more likely to be in favor of LRT, and that the most important measures to be taken are ensuring regular schedules and increasing the number of trains.

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In Japan, most of the intersections connecting multi-lane road which is expected mobility performance are controlled by at-grade signalized intersections. Reconstructing a signalized intersection into a grade-separated intersection will decrease signal control delay and ensures high potential performance, so that, it could produce certain benefits even at low traffic level. In this study, focusing on the signal control delay, we estimated the applicable traffic conditions of grade-separated intersection by comparing the time saving benefit and project cost, maintenance cost of the reconstruction of signalized intersection into a grade-separated intersection. The result shows that the traffic volume level which grade-separated intersection can be applied is not so high, and it is applicable even in a free flow traffic level during peak hours. It was also confirmed that many at-grade intersections that satisfy this traffic volume level exists widely in Japan.

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Time for waiting a train at a station is often a burden to passengers, which results in worsening convenience of railway service, thus losing its demand. Since it is difficult for struggling local railways to add more train services, efforts to introduce regular-interval or clockface timetable, which has periodic train services, are made to sustain and improve its convenience. However, it is unclear how characteristics of such timetables, for example length of train intervals or its regularity, affect the evaluation of its convenience. We therefore conducted a questionnaire survey to collect data on the evaluation of timetables with different characteristics, including number of trains or periodicity of train services. Collected data were then put into logistic regression models to quantify the magnitude of the effect of such characteristics on the convenience evaluation. Results revealed that both interval regularity and hour-by-hour cyclicity affect passenger convenience, as with an addition of train services.

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In recent years, bus ridership has been decreasing. In order to sustain the bus service network, it is expected that the importance of socially optimal route restructuring planning taking into account conflicting factors of costs for both passengers and operators will increase. Among various aspects of bus service designs, we focus on the route configuration and frequency designs of bus routes in this study. The number of candidate routes may become huge if the routes were enumerated based on the real road network, that may require enormous computational costs. To avoid this, we propose a design method that contributes to the schematic design of a bus route network at the inter-district level in a city. The proposed method consists of two steps: the first step is to simplify the problem by introducing the constraint that the network should have a spanning tree shape, and the second step is to simultaneously optimize the routes and the frequency using the exact solution method. The proposed method is applied to a hypothetical small network and the validity of the proposed model is examined.

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Regarding the aging of driver’s license holders, Japan plans to introduce a limited driver’s license that restricts driving a specific vehicle commonly known as “Safety Support Car.” In this study, various types of limited licenses were presented to elderly drivers, and they were asked about future driving intentions. The survey was conducted in two ways: a questionnaire distribution method and an interview method called “Driving History Interview” (DHI). Both methods included questions asking them to review their driving behavior and to consider the future situation related to driving. In addition, in the DHI method, the survey was conducted interactively, and information about “Safety Support Car” and the current situation of accidents among the elderly was provided. The results showed that the intention to continue driving changed before and after the survey, and that the change differed depending on the survey method. Furthermore, the logit model was used to clarify the factors of the intention to drive. Finally, we discussed the relationship between the roles of cars, people, and the road infrastructure in the process leading to fully automated driving.

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Conducting local public transportation scheme in rural area, it is important to grasp the needs for going outdoors in accordance with regional specific. In particular, there is a fairly difference between living environment in snowy cold region summer and winter. Therefore, it is important to make a suitable response along needs for going outdoors with each feature in summer and winter in a village in a snowy cold region. This study clarified how the difference between living environment in summer and winter affect the needs for going outdoors and the transportation in a village in a snowy cold region. As a result, it is suggested that the frequency of going outdoors in winter is reduced by snowfall compared with that in summer. And then it is suggested that people who are disinclined to drive in winter forced to drive in rural area. It is also cleared that there are some problems about using local public transportation in winter.

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For determining the runway capacity (number of arrival/departure slots) of congested airports in Japan, the capacity calculated based on the concept of “ultimate capacity” assuming continuous demand is used, but usually the demand fluctuates over time. It is desirable to determine the capacity from the concept of “practical capacity” determined from the viewpoint of the acceptable delay time while considering the demand fluctuation. Therefore, this study analyzed the actual inter-arrival/departure time using the latest aircraft trajectory data at Haneda Airport, and re-verified important parameters such as runway occupancy time. Using the newly updated parameters, how much the ultimate capacity and practical capacity change are analyzed, and the proposed capacity evaluation method that takes into account the effects of sudden incidents such as bird strikes is also examined.

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In recent years, new initiatives such as V2G operation have been active in the field of battery electric buses (BEBs), while changes on the energy infrastructure side such as the increase in renewable energy generation and the expansion of distributed generation, which is closely related to BEBs, have also been active. This study analyzes the constraints, interferences, and conflicts that arise between mobility, energy, and infrastructure when public electric mobility is considered based on the premise of widespread use of community grids. The simulator was developed under the assumption of multiple stakeholders surrounding BEBs in suburban area and under the situation where electricity can be traded between each stakeholder, such as households with EVs selling electricity at their destination. The results of the scenario analysis showed a significant decrease in the number of bus users and the revenue of the bus company, but also suggested the possibility of improving the revenue of the bus company through the operation of electricity trading by BEBs.

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As for deregulation of freight vehicle parking on local road, state of freight vehicle parking were analyzed to use three database, traffic accidents with parked car, illegal parking regulation and vehicle fuel consumption. To estimate traffic accident database, traffic accidents with parked car had decreased drastically after new law for illegal parking was enacted in June, 2006. Traffic accidents with parked car on local roads in 2019 had decreased more than 80 percent compared with these accidents occurred in 2005. Traffic accidents with parked freight vehicle on local roads had occurred more on wider road or in daytime than these accident with parked car on local roads. The rate of traffic accidents with parked freight vehicle in all these accidents with all vehicle is more than the rate of freight vehicle’s illegal parking regulations and vehicle kilometer in all vehicle. Traffic safety should be concerned as for deregulation of freight vehicle parking on local road.

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Personal mobility vehicle (PMV), which is a single-seater electric vehicle, can run stably in the low to medium speed range. It is expected that it can be mixed with relatively dense pedestrian traffic. For the acceptance of PMVs by pedestrians, it is necessary to appropriately evaluate the risk of conflicts between PMV and pedestrians even from the subjective perception by pedestrians. However, existing researches do not consider pedestrians movement restrictions due to the presence of other pedestrians, which are characteristic of mixed traffic of pedestrians and PMVs. This study proposes a pedestrian’s subjective risk evaluation index for PMV considering the movement constraints of pedestrians. As a result of analysis using behavior data and risk evaluation data from virtual reality experiments, it was shown that pedestrian risk perception for PMV is affected by movement constraints due to oncoming pedestrians, sidewalk width, as well as collision probability and collision intensity.

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Taxi is an important means of transportation that forms local public transportation. However, the declining trend of users in the long-term did not change, in addition to this, taxi business is facing various challenges increasingly during the COVID-19 crisis. In this paper, a survey was conducted to examine the actual condition and perspectives of small and medium sized taxi companies in whole Japan, impact of COVID-19 crisis on business management and the role of Taxi Subsidy Scheme (TSS). As a result, more than 50% of companies are facing the 60% drop on business sale compared to last year caused by the pandemic. As a role of Taxi Subsidy Scheme (TSS) on taxi business, about half of the companies said that TSS is an important service content, especially with small and medium sized companies, and by quantitative analysis of the business sale, we found that TSS has significant effect on the sale for taxi companies with 6 to 10 vehicles.

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In recent years, the annual number of traffic fatalities in Japan has been in a decreasing trend. In order to further reduce the number of traffic accidents in the future, it is necessary to appropriately understand the relationship between the unsafe driving behaviors such as traffic violations or dangerous driving, and drivers' cognitions on them, which may directly result in traffic accidents, so that effective traffic safety policies and enforcement can be implemented. Therefore, the objective of this study is to quantitatively figure out drivers' cognitions on various unsafe driving behaviors. According to the result of the structural equation modeling based on the questionnaire survey to Japanese drivers, it was found that the younger age group the drivers belong to, the more positive attitudes they would hold for unsafe driving behavior and the more confident in their driving skills. Besides, the difference of influence by age group is particularly significant in drunk driving and careless driving, while less in overspeed driving.

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A previous study has shown that traffic capacity and operational performance of expressways declined from 2003 to 2016. However, they did not explain why this phenomenon occurred. Besides, no previous studies have showed the secular change of both observed breakdown flow rate and queue discharge flow rate. In this study, after analyzing the traffic capacity of bottlenecks on interurban expressways from 1996 to 2019, it is confirmed that both the breakdown flow rate and queue discharge flow rate declined over time. At the latest, the decline began in 2013 to 2014 for the former and in 2001 to 2008 for the latter. It also showed that the decrease of traffic capacity over time can be attributed to an increase in the volume of heavy vehicle traffic and in the heavy vehicle ratio, as well as to changes in traffic quality (characteristics).

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With an increasingly aging population and the deregulation of policies concerning public transportation, securing the mobility of elderly people, especially those living in rural areas, has become a serious problem. This study aimed to clarify the actual conditions and issues for elderly people when using taxi services, and to examine the role of a taxi subsidy scheme (TSS) as a future policy for securing the mobility of elderly people in rural areas. By using a web questionnaire survey with 300 people over 65 years old and able to go out by themselves, a comparative analysis was conducted between three focus groups: people with private cars, people without a private car and with no TSS, and people supported by a TSS. The results show that the TSS has a certain effect on ensuring mobility for the elderly in depopulated areas. People without the ability to use public or private transportation freely showed a strong desire to increase the subsidy rate and number of usage instances. In view of this, the utilization of a “shared taxi” reservation type is suggested for improving the subsidy rate.

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In this paper, effect of the guide beam is validated by the result of experiment with driving simulator. In the experiment, two kinds of the guide beam such as (7m bright) and (15m dark) are used to compare the case without having the guide beam. It is clearly shown that ease of driving for following drivers and perception of distance between vehicles are improved certainly by the result of questionnaire. Moreover, it is found that frustration and feelings of overtake are suppressed. In the situation of the approach to the maintenance vehicle, number of cases with higher deceleration is decreased by the guide beam from the result of driving behavior analysis. Additionally, in the situation when maintenance vehicle changes its speed, reaction time to accelerate/decelerate their speed is shorten by the guide beam. Furthermore, in the following situation, following drivers keep safe condition. Summarizing these result, it is clearly shown that the guide beam has high advantage to make safer traffic conditions.

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In Arao City, Kumamoto Prefecture, mobility management (MM) has been continuously implemented for three years for active elderly people. In this study, we developed a kind of disaggregated conversion model to public transport that takes into account the attrition bias caused by samples that drop out from each step of the Travel Feedback Program (TFP), which is a typical technique of MM. As a result of model estimation, it was confirmed that those who continuously participate in TFP have a bias the make it easy to change the travel mode from car to public transportation. Furthermore, it was clarified that what individual attributes, level of service and information provided affect behavioral change at each stage of TFP.

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In recent years, the air transport industry and economies of European countries had encountered disruption significantly from a volcanic eruption. In Japan, there are many active volcanoes, and it is expected that large-scale volcanic eruptions will have a great impact. In the previous research, the authors formulated the aircraft evacuation problem for the risk of large-scale volcanic eruption and proposed an optimization model that minimizes the total evacuation time of each aircraft. However, this model did not consider temporary mitigation of airport capacity in an emergency and could not evaluate airport-side countermeasures. Therefore, we constructed an aircraft evacuation model including the relaxation of airport capacity as a variable in this study. In that case, we used CARATS Open data for the position of the aircraft, and the genetic algorithm to optimize the combination of aircraft evacuation destination allocation and airport capacity mitigation levels. As a case study, we assumed the eruption of Sakurajima and analyzed it.

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By providing information on the potential risk of traffic accidents, i.e., “accident risk,” it is expected that the safety of individual trips will be improved and accidents will be reduced by shifting demand to safer routes. As accident risk indicators that have the potential to provide road users with incentives for route guidance, in addition to accident occurrence risk information, “accident encounter risk,” which indicates the likelihood of encountering an accident scene while driving on an expressway, and “accident loss risk,” which is the amount of loss that may be incurred while driving on an expressway, are included. In addition to the risk information of accidents occurring, two indicators have been proposed: “accident encounter risk,” which indicates the possibility of encountering an accident site while driving on the expressway, and “accident loss risk,” which is the amount of loss that may occur while driving on the expressway. In this study, we evaluate the expected effects of route guidance and accident reduction when these different quality accident risk indicators are provided to road users. Specifically, we analyzed the effects of providing various accident risk indicators on the route selection rate of road users using a route selection model that takes accident risk information into account for the NEXCO West network with route selection, and quantitatively demonstrated the accident reduction effect of providing accident risk information.

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This study analyzed both changes in vehicle behavior and user evaluation at a roundabout (RAB) located in government district by observation and interview survey. It is found that there is a decrease in the velocity of free-flowing vehicles at the entry/exit of RAB by before-after analysis. It was revealed that the proportions of vehicle yielding behaviors for crossing cyclists at crosswalks were higher than those of before situation. In addition, the safety situation at stoplines of non-priority roads was improved after installing the RAB. As the result of interview analysis compared between immediately after situation and three month after situation, it is found that the safety evaluation and impression for cyclists became better and the their perceptions of traffic rules at RABs were slightly improved, on the other hand, the evaluation for drivers showed little change from before situation. From the results of statistical modelling, it was revealed that users’ impressions were improved by the low conflict risk at RAB, the safer evaluation for the RAB and the ease of passing through the RAB for both drivers and cyclists. In addition, it became clear that the safety impression of RAB varied according to their age groups.

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In recent years, it has been reported that the traffic capacity of expressways has been declining over the years. In the previous study, it has been pointed out that the characteristics of drivers behavior have been shifted from high-speed and short-headway distance to reduced-speed and widen-headway in the last decade. If this difference of driving behavior was caused by the change of drivers attitude to traffic safety, such changes in driving behavior may also contribute to enhance traffic safety. To prove this hypothesis, in this study, we analyzed the time series variations of traffic accident risks for 13 years at 9 sections of intercity expressways explicitly considering the traffic condition of the entire section. In addition, the relationship between the time series variations of traffic capacity and the traffic accident risk is analyzed. As a result, it is revealed that the traffic accident risk significantly increase especially in the critical traffic state and jam flow state in multiple sections for rear-end collision, whereas for sidewipe and road facility collisions the traffic accident risk significantly increase especially in the free flow state. Also, it is confirmed that the correlation between time series variations of traffic capacity and accident risk shows negative value in multiple sections, implying that the less traffic capacity becomes, the more often traffic accidents occur. These facts suggest that the countermeasures preventing distracted driving and drawing drivers attention at bottlenecks are essential for enhancing traffic safety as well as increasing traffic capacity.

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In recent years, shared taxis have been attracting attention in Japan. From October 1, 2020, Arao’s “Omoyai Taxi”, which is a substantial “shared taxi”, started operation. However, there is not enough consideration on the service setting of shared taxis and the appropriate setting of the number of vehicles in rural areas. In this study, we conducted two surveys those are house hold travel survey and stated preference survey for ride-sharing taxi to estimate a conversion model. Sensitivity analysis is performed using an operational simulation model connecting K-MATSim with SAVS by Web-API. A comparative analysis is performed between the predicted value by the operation simulation and the actual usage. Finally, the purpose is to update the conversion model.

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At the roundabouts introduced so far, some kinds of effects in safety such as decreasing the travel speed or reducing the number of accidents have been reported compared to before the introduction. However, drivers might become accustomed to driving a roundabout after a certain period since the introduction. Therefore, monitoring the changes in vehicle behavior over time is considered to be important. In this study, investigation on changes in vehicle behavior such as speed, acceleration, and position over time using videos taken with a drone about 22 months, 28 months, and 55 months after the introduction was conducted. The result shows that the speed at the entry leg approach has increased, but the speed at the circulatory road or the exit leg has not changed so much.

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This paper examines the theoretical properties of a departure time choice equilibrium in a tandem bottleneck network with endogenous demand distributions that are determined through an upper-level choice (e.g., mode choice and location choice). We first show that, for two-bottleneck networks, we can analytically classify equilibrium flow patterns based on the cost difference in the upper-level and the capacity ratio of the adjacency bottlenecks. We also show that this classification is useful for more general problems such as networks with an arbitrary number of bottlenecks, and capacitated upper-level choices. We finally discuss the relationship to a socially optimal state.

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In a walking space of public facilities such as a station, people who need various functions such as mobility and rest are mixed. However, the existing evaluation methods for mobility function do not take into account the mixture of standing or stopping people in the walking space. In this study, the subjective evaluation of the pedestrian mobility function was evaluated by questionnaire survey using videos of Virtual Reality environment in which a pedestrian is walking through a corridor conflicting with other walkers and standing people. It was found that the pedestrian density, the standing person density, the distance from the wall, and the number of lateral movements of the subject pedestrian worked significantly as explanatory variables. The applicability of the model was examined by applying it to traffic simulations and real space videos. As a result, although limited to a small range of pedestrian density, it was confirmed that the model can express the subjective evaluation of mobility function.

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In recent years, analysis of traffic accident risk has been progressing in order to reduce traffic accidents, and it is thought that traffic accidents will decrease and social benefits will increase if traffic on ordinary roads is shifted to expressways, which are safer routes. In addition, the risk of traffic accidents increases during bad weather, and the difference in safety between highways and regular roads becomes even larger. In this study, we focused on the traffic conditions during snowfall and clarified the changes in traffic volume due to weather conditions in the Niigata metropolitan area. We also reproduced the current traffic conditions during snowfall in a simulation, and evaluated the effects of applying route guidance measures to expressways. As a result, it was confirmed that the traffic volume decreased significantly during snowfall compared to that during clear weather and rainfall. In addition, it was suggested that the number of traffic accidents could be reduced by about 5% when the expressway toll was made free.

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In this paper, a novel visibility estimation method based on spatial frequency and deep learning-based features by introducing the mRMR algorithm to the spatial frequency calculation is proposed. The mRMR algorithm is a well-known feature selection algorithm in the field of image recognition. By introducing this feature selection, a method for estimating visibility based on minimum-Redundancy-Maximum-Relevance in spatial frequency features can be realized. In the last of this paper, we verify the effectiveness of the proposed method by the experiments used the actual CCTV images. By utilizing the proposed method, since the poor visibility can be estimated automatically, we expect to reduce the risk of a transportation accident.

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As Japan's birthrate declines and the population ages, the percentage of people with mobility constraints is expected to increase in the future. For this reason, the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) is aiming to promote the use of pedestrian mobility support services consisting of positioning technology and information data. In this study, we aim to enrich the pedestrian network data included in the information data, which is a component of the pedestrian mobility support service. Past research has shown that it is possible to detect road surface barriers using 3D point cloud data by forming a grid of 3D point cloud data and comparing adjacent grids. However, the accuracy of road surface barrier detection may vary depending on the direction of the sidewalk because the grid is formed based on the north. In this study, we will examine how coordinate transformation affects the accuracy of sidewalk curb and crossing slope detection when understanding the shape of the road surface for wheelchair route guidance.

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The accident risk on residential roads is higher than that of highways. Especially, the intersections on the residential roads are more dangerous because of the large number of accidents. Therefore, in order to identify the factors affecting the number of accidents per unit traffic volume (hereafter, "traffic accident risk") at the intersections, this study makes a factor analysis for the intersections in Matsuyama metropolitan area. Since there are a lot of intersections with blind corners, in addition to road structure etc. the visibility of the intersection is considered as a factor. Specifically, by combining probe data and traffic accident data, a multiple regression analysis is carried out, using the number of traffic accidents at the intersections in each area as the objective variable, and various factors including intersection visibility as explanatory variables. As a result, it is shown that the accident risk of the 4-way intersections increases where narrowed roads intersected and good and bad visible corners were mixed.

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The transport sector accounts for about 20% of Japan's CO₂ emissions, of which freight trucks account for about one-third. In addition, heavy duty large trucks are behind in decarbonization due to electrification, etc., compared to passenger cars, and it is necessary to consider the actual traffic characteristics of them. The objective of this study is to examine the possibility of decarbonization of heavy duty trucks, especially for long-haul truck transportation with the distance of about 1000 km, using the Well to Wheel analysis to trace back to primary energy sources. We estimated the cost of electrification, which is expected to be a major issue. As a result, we found that it is difficult to reduce the carbon content of heavy duty trucks by electrification with the current power source configuration, and it is essential to reduce the carbon content of the power source.

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This paper proposes a novel train operation scheme for high-frequency railway systems with the fast train coupling technology that makes a possible to change the number of vehicles for each train flexibly. Specifically, the proposed scheme generates a new local train from an express train at every stop station in the outbound direction, and conversely, in the inbound direction, couples these local trains with an express train at those stations. We construct a simple continuum approximation model to describe the proposed scheme, and compare it with a conventional scheme, and clarify the features and advantages of the proposed scheme.

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