Hideyuki Kita

A merging-giveway interaction model of cars in a merging section: a game theoretic analysis

In many past studies dealing with traffic phenomena in merging or weaving sections, only the influence of through traffic on the behavior of a merging car is considered in the analysis. It is, however, often seen that a through car, which runs on the most outside lane, takes a cooperative motion for the merging car called giving way by moving to the adjacent lane. That is, both the merging car and the through car affect one another. Because their influence is not independent from one another, it should be jointly treated in the analysis as interaction. This behavior is typical in merging sections, and is a dominant factor forming the traffic phenomena in a section of this type. This study develops a game theoretical model to describe the traffic behavior of a pair of merging and through cars, while explicitly considering the interaction between them. Both the merging and through cars attempt to take the best actions for themselves by forecasting the others action, respectively. Such a behavior is modeled as a two-person non-zero-sum non-cooperative game. Through a case study with data analysis of videotaped observation, the proposed model can be used to obtain an understanding of traffic behavior at on-ramp merging sections. ©

Information Basis for Public Transportation Planning in Rural Areas

This study discusses the appropriate information required for public transportation planning in rural areas. The needs satisfaction which has been widely used as an information basis is arbitrary because a person may adapt to the poor transportation accessibility and thereby comprising the level of needs for the service. We argue that the accessibility measurement is more appropriate than the needs satisfaction measurement. We formulate the accessibility measurement method for public transportation planning in rural areas. Based on space-time prism, a measurement method is developed to calculate the possible plans of daily life activities subjected to constraints caused by the public transportation services.

AN EVALUATION MODEL OF THE LEVEL OF EMERGENCY MEDICAL SERVICE IN SPARSELY POPULATED AREAS

In rural areas, services to support daily life are generally short and a large disparity exists from place to place. This study proposes an index to measure the level of emergency medical service, a minimum service to support daily life, at given locations. The required characteristics of the level of service index are firstly discussed, and then an accessibility type index is proposed with holding the characteristics pointed out in the discussion. By using this index, we develop a systematic method to find the sub-system of that improvement that contributes the most to raising the level of service. This method gives us the order of improvement over sub-systems under the restrictions of budget, time, and other resources. The usefulness of the methodology is examined through a case study.

Design of Driving Environment, Driving Behavior, and Traffic Safety

The primal causes of traffic accidents are due to drive error such as insufficient watching or poor driving technique, however it is also a fact that there exists a safer driving environment where drivers make fewer mistakes and/or the drivers’ mistakes do not necessarily cause accidents. Drivers operate their cars by watching their surrounding conditions and processing information continually. If we call such surrounding conditions the “driving environment”, then prevention measures for traffic accidents can be understood as the actions that form a safer driving environment. In this environment it is important to clarify the relationship between the driving environment and the level of traffic safety. Effective traffic safety measures can be launched when we grasped the process of how the change of traffic environment affects the safety level of traffic.

A data analysis of equilibrium selection

A commonly accepted criterion of equilibrium selection has not been established. This situation exists because we do not have sufficient information about what sort of equilibrium is selected in real games. In this experimental study, we investigate a set of games and estimate the selected equilibrium of each game by using an estimation model of equilibrium selection. Through the analysis, a criterion that rules these games in the experiments is identified, and the usefulness of the approach is demonstrated.

A performance based planning of water supply service system under seismic risk

This study aims to develop a model where the level of water supply means is determined from the view point of the performance level of water supply system in the occurrence of a severe earthquake. We focus on that the performance level depends not only on the remaining water supply system from the earthquake but also on both the local conditions and the attribute of residents. As a result, a resultant extent to upgrade waterworks in terms of earthquake-proofness which determines the supply level of waterworks can be found by comparing the benefit and cost of their upgrading under the given local conditions and the attributes of residents.