In this research, we try to construct a method for grasping a process of a potential accident risk using probe data for Meihan Expressway (bypass of route 25) where traffic accidents caused by excessive speed occur frequently. Binomial logistic regression analysis was applied to the extraction of intervals inducing potential accident risk. As a result, it became clear that the point where the difference in the speed transition exists on the upstream side of the actual accident frequently occurring section compared to the safety traveling and traveling with a high potential accident risk.
Most studies on travel time reliability (TTR) for roads are single-route section basis due to the availability of sufficient number of travel time observations. Recent years, there have been increasing possibilities of observing network-wide traffic states for long time period with the rapid accumulations of rich probe datasets and it is expected to evaluate TTR for area-wide level rather than route/section levels. This study proposed TTR evaluation method for general space-time domains by using total distance traveled and total travel time that are aggregated based on the generalized definitions of traffic state. We demonstrated the validity and the applicability of the methodology using national level probe dataset by focusing on cross-spatial and cross-seasonal differences or effects of traffic regulations in area-wide TTRs.
We study the effect of preference elicitation mechanisms on the efficiency of auction result using laboratory experiments. For transportation service and reservation systems, it is important for service providers to know the potential demand of users. However, the user interface and preference elicitation method can have impact on the elicitation result by users. In this study, we analyze the effect of preference elicitation mechanism on the users' eliciting behavior and the efficiency of auction result based on experimental approach. In addition, we show that our preference elicitation mechanism can reduce users' cost of bidding and it improves the efficiency of auction results.
The present study aims at promoting the intention of modal shift on commuting with mobility management in local city. The effects of information for health support and environmental concern are estimated to influence intentionally of modal shift on commuting by car with the support of information for health support and global warming based on the questionnaire survey in Tokushima city. Therefore, The factors for promoting the intention of modal shift are identified. As a result, appropriate information promoting intention of modal shift for car commuter. It can be found out that not only active awareness but also interest in environment influences the intention of modal shift with simple request. On the other hand, the advise can be effective, which includes the issue of disease risk, physical active mass and the global environment problem, for the trip makers without reaction for the simple request.
This paper summarizes recent advances in the kinematic wave (KW) theory of traffic flows. First, we review the variational formulation of kinematic waves and its application together with pointing out the limitations of its conventional analysis methods. Second, the KW theories for the network traffic are introduced. Specifically, we review and summarize the methods/conditions to determine boundary flows of links at multi-lane roads and intersections.
Dynamic traffic control schemes considering chaotic queue and route choice behavior of drivers are desired for controlling oversaturated road networks. In this research, we formulate a dynamic social optimization problem for oversaturate network in time delay systems, and interrupt the necessary condition. Then we focus on closed-loop structures in road networks and show the constrained conditions to avoid gridlock phenomena. Considering these conditions, we propose a traffic control scheme called Z-control, which minimizes total travel time based on a model predictive scheme. In numerical studies, we consider 2 scenarios for drivers' route choice behavior and show the effectiveness and remained problems of our proposed Z-control.
This research focused on the relationships among travel behavior, health condition and indicators to measure mental tendencies such as driving motivation, attitudes towards transportation, social capital, the Big Five and Subjective-Well-Being. Questionnaire survey (n = 479) was conducted among employees in Yamato city, Kanagawa prefecture, 180 of them agreed to provide medical examination data for research purposes. As a result of the analysis, the number of metabolic syndrome people who use cars and motorcycles to commute were about twice as many as those who use other transportation. It was also shown that those who use cars and motorcycles for business purposes tend to have metabolic syndrome and higher BMI. In regard to mental tendency, as a result of good relationships with the organization and participation in regional volunteer activities; it was shown that there is a tendency of metabolic syndrome and high BMI. The reason of this may due to the fact of frequent joint dining at workplaces or after volunteer activities. Since metabolic syndrome is a state of accumulation of risk factors and subjective symptoms are imperceptible, it is necessary to pay attention when analyzing combined mental tendency as health index.
The objective of this study is to develop a system that citizen can report inconvenience parking which cause traffic accident and traffic jam, to clarify the distribution of such a parking vehicles, and to evaluate the effect of this system. The goal is to reduce inconvenience parking. The method is that we developed the system which can be used by smartphone and conducted a test to collect data of actual condition of inconvenience parking. Using the data, we visualized the distribution of inconvenience parking, and clarified that this system can encourage citizen to change their parking behavior, and reduce inconvenience parking. And, it can also be used as a means to grasp the distribution of on-street parking which would be a risk of traffic accidents, and expected to contribute to traffic safety.
This study examines the effects of mobility management to promote bus use and to reduce car use, focusing on individual health consciousness. A case study was conducted for people living in a district where the new bus line was introduced in Utsunomiya city. Information on calorie consumptions, CO2 emissions, traffic accidents, and opportunities for encounter were provided in the questionnaire to affect individual attitudes and travel behavior. The results show that environmental attitude decreased two month after providing information, but health attitude continued improvement. Regarding the way of managing calorie balance, about 80% of respondents will not change travel behavior but increase physical exercise or decrease calorie intake. Older people tend not to change daily behavior for calorie balance, women tend to be affected by information on calorie consumptions and change travel behavior. The travel purposes which more respondents will decrease car use are grocery shopping, eating out and leisure.
This study makes a factor analysis of the traffic accident risk in 2 regions, Tokyo and Ehime prefecture. Comparison analyses of the factors are carried out considering the land uses, which affect the rear-end collision accident risk. Region, land use, hourly traffic volume and road structure are considered as the factors, Poisson regression analysis and Negative Binomial regression analysis are carried out using the Road Traffic Census in 2010 and the traffic accident records in 3 years from 2012 to 2014. As a result, it is shown that the impacts of some same factors in Tokyo and Ehime are significantly differential effect of factors. For example, the rear-end collision accident risk can be increased when the level of traffic volume is highest (more than 800 vehicles/h/lane) at DID district in Ehime prefecture, and the traffic accident risk at DID district in Tokyo is decreased at the same level as the hourly traffic volume. On the other hand, the traffic accident risk at DID district in Tokyo is increased as the density of signalized intersection increase and the traffic accident risk at the other district in Ehime prefecture can be increased in accordance with the number of signalized intersection per kilometer increased.
In the strategic maintenance and renewal of road traffic infrastructures, effective methods to reduce total cost and equalize the budget have been required recently. Under such circumstances, availability of pedestrian-control signals installation and suitability of signal phase operation should be considered properly based on traffic situation of crossing pedestrians. In this study the authors investigated the factors of control button using decision by multivariable logistic regression analysis based on the observation data, in order to understand usage characteristics of pedestrian-control buttons at intersections. As the result, we found that it is necessary to consider the pedestrian attribute and the road structure in addition to the traffic volume of the vehicle for the evaluating availability of the pedestrian-control signals installation. Furthermore, from the aspect of the pedestrian waiting time and the vehicle delay time, superiority of installation of pedestrian-control signals was discussed using the traffic simulation model.
The long-term objective of this research is to analyze quantitative effects of introducing advanced methods for controlling air traffic flows to Tokyo International Airport. As the first step to archive this purpose, in this paper, the current capacity of terminal airspace to Tokyo International Airport was analyzed by using ADS-B and ATC instruction data. An airspace simulator was developed by considering the characteristics of ATC instructions. Using the simulator, the performance of Point Merge operation which is one of advanced navigation methods was briefly examined in a virtual airspace.
“Sharing economy”, including car-sharing and ride-sharing, and autonomous driving will change our society and transport in the near future. To effectively introduce ride-share-based transport service into a society, we need to estimate the required number of vehicles and determine route and schedule of vehicles, based on travelers' activity. We also need to understand how spatial and temporal characteristics of travelers' activity patterns affect the performance of this sharing service. Previous studies have tried to estimate benefit to introduce ride-share transport. According to the related papers, the objective of this service is generally to minimize the total travel time of vehicles, but it may prevent travelers to carry out their activities as they planned. The objective of this study is to investigate features of society that ride-share transport would be successfully operated in the above context. The optimal vehicle routing and scheduling problem which satisfies all the travelers' activities is formulated as an integer linear programming problem. By using the proposed model, numerical experiments to find optimal vehicle routings are conducted with different types of activity patterns. The results show spatial and temporal distribution of travelers' activity patterns that ride-share transport service achieves positive impact.
Critical gap is an important parameter for not only entry capacity estimation but also safety evaluation at roundabouts. This paper gives an overview on the existing procedures for estimating critical gaps and compares them by applying into an empirical data observed at a roundabout in Japan. Application of other procedures than Raff's method, which has been commonly used in Japan, enables to estimate not only a single representative value of critical gaps (e.g., mean or median) but also their distribution. Through a comparison, differences of the estimated critical gap distributions are presented and discussed considering the limitation in the observed samples.
The issue on moral consciousness occurs in many engineering fields, including civil engineering. One of the ways to solve this issue is the promotion of the behavioral change by stimulating moral consciousness. The objective of this study is to investigate relationship between behavior and moral consciousness when people face a social issue on moral by fMRI experiment. We collected two types of participants, one with legal and the other with illegal cycle parking. We observed the change of the brain regions of the participants that were supposed to be associated with moral consciousness when the participants were requested to answer the choice between non-cooperative and cooperative behaviors in response to hypothetical social issues. We found that brain activation was different between legal and illegal cycle parking persons.