In Japan, about 60% of bicycle-related accidents occur around intersections every year, and accidents at intersections have become a problem because of violations of laws and regulations by bicycle users. In addition, the "Guidelines for Creating a Safe and Pleasant Environment for Bicycle Use" issued in 2012 states that it is important to grasp the road space and actual conditions of bicycle use in order to formulate a bicycle network plan. In this study, behaviors of bicycle users were recorded by using GPS data, and the relationship between their behaviors at intersections with a stop sign and the road elements at the intersections was examined. First, the rates of stopping and slowing down at the intersections were calculated to grasp the actual condition. Moreover, multivariate analyses were conducted on the compliance to stop and slow down, the passing speed at the intersection, and the deceleration rate just before the intersection, and the factors that are thought to affect each behavior were clarified.

The Ministry of Land, Infrastructure and Transport of Japan has started a project, which is one of the policies to protect the citizens from traffic accidents, to utilize probe data such as ETC2.0 probe data in road projects. However, sudden braking data include both risky braking events caused by averting automobile accidents and non-risky braking events caused by deceleration behaviors at red light signals, 'STOP' signs, etc. Therefore, to lead an accurate traffic safety counter by using sudden brake data, researching the characteristics of sudden brake to identify true potential hazard spots are necessary. In this paper, to extract the real potentially dangerous spots (or areas), We focus on the wave form of driving recorder data. Basing on the analyzing results of the feature amounts of wave form by using multivariate analysis (Non-hierarchical cluster analysis and Decision Tree), we propose an index for determining risk events and non-risk events.

Due to the snowstorm or the accumulated snow on the road of expressway, it is hard for drivers to check the road geometry. As a countermeasure to solve this problem, Guide Light was developed. However, differences between the Guide Light and conventional delineator were not shown in the previous study. The aim of this paper is to evaluate the effect of Guide Light through the experiment with driving simulator. Results of the experiment show the advantages compared to the delineator. When Guide Light is installed at the section, vehicle's lateral location of the road is stable compared to the delineator section. Moreover, large speed reduction is not appear in the Guide Light section. By the questionnaire to evaluate the feeling for each sections, it is clarified that driving stress is decreased and visibility of road geometry is improved. It also clarified that Guide Light have more than twice positive effect to the driveability compared to the conventional delineator.

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. When drivers overtake bicycles on roadways, they often overhang the centerline on single lane road that is not wide enough. As a result, depending on the approach of oncoming traffic, bicycles on the roadway might even affect cars in the opposite lane, such as causing avoidance behavior of oncoming traffic. In this study, therefore, we examined the drivers' overtaking behavior of bicycles and the influence of their overtaking behavior on the driving behavior in the opposite lane. Based on a bicycle riding survey on roads of different widths, the overtaking behavior of drivers was clarified. Then, based on the results, driving experiments using a driving simulator were conducted, and the effect of bicycles on the roadway on the driving behavior in the opposite lane has been clarified.

In order to improve the accuracy of the Time-of-day User Equilibrium assignment for countermeasures against traffic congestion during peak hours, an Hourly OD Flow Estimation from observed traffic flows based on time coefficient of daily OD flow has been developed. In this study, we examined issues such as the computational efficiency of this method in the stepwise estimation of out-of-area and intra-area OD flow. In addition to the three-step estimation method of the previous study, the two-step estimation method and the simultaneous estimation method were examined, and the estimation accuracy was compared. As a result of the inverse estimation, the simultaneous estimation method was found to have the best estimation accuracy as a whole, and the calculation time could be significantly reduced to approximately 1/3. However, in the estimation of out-of-area OD flow, excessive upward and downward fluctuations of the time coefficient were found, so we considered multiplying the weight coefficient of only the out-of-area OD flow pair by a correction multiplier. In terms of the overall estimation accuracy, it was found that the accuracy was even better with a correction multiplier while suppressing the excessive fluctuation of the time coefficient.

The purpose of this study is to clarify how many people own a car for motivation other than improving mobility. It is also to understand the characteristics of people who own a car for motivation other than improving mobility. Because of the analysis, the following became clear. First, the importance of motivation to own a car other than improving mobility was 23.3%. Second, 12.8% of people own a car for motivation other than improving mobility. Among them, 7.9% of people own a car as a hobby. 4.9% of people own a car for no reason. Thirdly, the characteristics of people who own a car for motivation other than improving mobility are as follows. A man without children and a woman who is a housewife own a car for a hobby. Housewife with children and people with low annual income own a car because they care about the evaluation from others. People living alone and woman own a car for no reason.

The older drivers' proportion in the fatal accidents are increasing due to the aging society. In many rural areas, it is difficult for them to give up driving due to the lack of alternative transportation, and the rate of driver's license surrender is low. In this study, we analyzed the relationship between the driving behavior of older drivers, older drivers' accidents and their local environment. We assumed that, in addition to factors such as alternative means of transportation, the driving frequency and driving skills of older drivers vary due to the differences of transportation environment of living location, such as land use, road usage and road congestion. We analyzed the relationships using the data collected in Chiba prefecture. The results showed that there were significant differences in the unsafe driving behavior of older drivers in different region. It was confirmed that significant relationships between land use, driving frequency, and other factors and the occurrence of accidents. From these results, we obtained directions for the measures to prevent accidents involving older drivers in each region.

In this study, vehicle behavior at intersections with more complex geometric structures than crossroads was analyzed by simulated driving experiments using a driving simulator (DS) to compare the behavior of vehicles in response to different signal light positions and to obtain knowledge for studying appropriate light positions. In conclusion, under conditions of risk of rear-end collisions at complex intersections, the near type had a higher passing decision rate than the far type when the signal was switched, the near type stopped farther from the stop line than the far type in the analysis of stopping positions, and the near type stopped farther from the stop line than the far type at some complex intersections. In the analysis of stopping positions, the near type stopped farther from the stop line than the far type. Thus, the results suggest that the near type has improved safety more than the far type, and this was more pronounced at complex intersections.

When an auxiliary lane is installed in an uninterrupted section of a multi-lane expressway, the climbing lane type, i.e. adding and ending the auxiliary lane from shoulder has been generally adopted, and other types including field trials have also been introduced. The lane-changing behavior is important for traffic operation in the auxiliary lane section. No research, however, has been conducted of the effect of sign arrangement on the lane-changing behavior. After analyzing the relationship between sign arrangement and lane-changing behavior in the auxiliary lane section based on video observation results, the study calibrated a microscopic simulation model that takes into account the effect of sign on lane-changing behavior, and examined the effective arrangement of the sign in the auxiliary lane section with lane addition and closure from shoulder. As a result, it was confirmed that the advance sign affects some drivers' lane-changing behavior, and that it is effective for smoothness and safety to place the advance sign at the start point and 1 km before the end of an auxiliary lane of 2 km long.