In this study, we propose a method of modeling spatial dependence on pedestrian fundamental diagrams. A fundamental relationship between density and speed of pedestrian flow is useful with regard to evaluating the level of service in pedestrian facilities. However, this relationship always depends on the position although there is typically a lack of a priori knowledge regarding the position of bottlenecks, i.e., the position to be evaluated. Therefore, we propose an approach to use data obtained at entire area in a facility. We assume that the difference of fundamental diagrams at any position in a facility could be regarded as a fluctuation. This fluctuation over positions is modeled as a spatial dependence structure. The harmonic spatial filtering approach is employed to estimate the fundamental diagram and spatial fluctuation pattern simultaneously. We show that the regression accuracy of the proposed method is better than that of a non-spatial model. Furthermore, we interpret the estimated spatial fluctuation pattern over the entire experimental area, which might be useful in facility design.
Probe data collected by ordinary vehicles are being used to observe temporospatial change in travel times on road networks. However, the number of observations can be insufficient due to detouring by probe vehicles on congested road links, especially in provincial cities. The authors proposed a method for supplementing this insufficiency with estimated running trajectories of ordinary vehicles by correcting bus location system data and statutory digital tachograph data of buses at bus stops. On the other hand, differences in traffic conditions between the estimated running trajectories of ordinary vehicles and the real ones needed to be addressed. This study confirmed that these differences in traffic conditions could be decreased by applying the time-slice method into temporospatial meshes where interpolated expected travel speeds were set based on the above estimated running trajectories of ordinary vehicles. In addition, the precision of real-time estimation based only on the bus location system data was verified.
"Guideline for creation of safety and comfort bicycle environment" published by The Ministry of Land Infrastructure and Transport and The National Police Agency appears the policy that bicycle network plan should be formed mainly by bicycle lanes and shared lanes on carriageway. Because, most of cyclists, however, are afraid of running on the carriageway in Japan, improvement of safety sense towards carriageway is needed to promote cycling on carriageway. The aim of this study is to make clear the relationship between cyclists' safety sense and the conditions of streets and traffic characteristics along bicycle space. WEB questionnaire survey showing the video from bicycles was carried out in order to search cyclists' safety sense for 22 streets of various type of bicycle infrastructure selected in Tokyo Metropolitan area. As results, factors related to overtaking behaviors are significant, and existence of bicycle lanes or shared space on roadway has effects on the safety sense.
The ultra light-weight vehicle (ULV) is developed as a compact vehicle. Generally, the ULV is powered by an electric motor, and the output is lower than a general gasoline engine vehicle. Therefore, the maximum speed is set low. In the study, the difference of run properties between the ULV and the normal vehicle is clarified. Furthermore, the traffic flow is analyzed on the road where ULV was mixed. As a result of the investigation, the acceleration of ULV at the time of departure is usually higher comparison with a normal vehicle. When the travel speed exceeded around 40 km/h, acceleration usually lowered in comparison with a normal vehicle. As a result of examination by the traffic simulation, when a traffic density is relatively low, the average travel speed is lower if the ratio of the ULV is high. On the contrary, the average travel speed is higher if a traffic density is relatively high.
Currently about 60% of traffic jams on express highways nationwide are said to occur at sag sections, as traffic congestion at tollgates decreased significantly with the introduction of electronic toll collection system (ETC). Therefore, in order to further decrease traffic jams on express highways, there is an urgent need to consider measures to reduce traffic congestion at sag sections. A wide variety of hardware and software has been suggested to deal with traffic jams. In this study, a measure for suppressing traffic congestion at sag sections has been proposed, expected to be low in cost and readily installed , which utilizes optical illusions for drivers. An experiment which used driving simulator resulted in suggestion that setting gates at incremental intervals at uphill sag sections resulted in suppression of speed reduction in those sections .
This research studies the resting behavior of inter-urban expressway users. For the better understanding of those resting behavior, ETC2.0 probe data seems promising since it contains individual vehicle trajectories. As a preliminary step to the resting behavior modeling, the study aims to build the database of resting behavior of each trip using the trajectory information of ETC2.0 probe data and to analyze the characteristics of the trajectories and resting behavior so as to yield some insights into the resting behavior modeling through basic analysis. In the study, resting behavior in free flow state was extracted with high precision to build the resting behavior database. A simple determination method was proposed to discriminate resting at service or parking area from passing it, which is quite difficult to judge from the probe data when queue forms on the mainline. The study also obtained some findings of the points to note in making use of the present ETC2.0 probe data such as the bias in the composition of vehicle types and separation of trips covering two successive days, basic aggregate results of rest time distribution and number of rests, relationship between successive rests in one trip.
Although five years have passed since the Bangkok Bus Rapid Transit System started the operation as one of the mass transit system in Bangkok, it has a problem that the number of users is less than expected. At first, this study aims to identify factors of on-time operation of the system from the results obtained in observation surveys. In addition, the authors conducted awareness surveys for users and non-users of the system in Bangkok and evaluated it from the demand point of view. According to the analysis, this study indicates that there is stable demand for the Bangkok BRT, improving evaluation of punctuality leads to an improvement of comprehensive satisfaction with the system, willingness to pay, and ratio of acceptance of the alterations of the fare system. In conclusion, the enhancement of the evaluation of punctuality is the key to the stabilization of the Bangkok Bus Rapid Transit System management.
Expressway interchange (IC) is the only access point to the expressway-space with access restrictions, and it is one of the most important factors for determine the function of the expressway. In the history of expressway construction, as part of the measures to improve convenience, many additional ICs had been developed nationwide, and it is planned to develop many additional ICs including smart-ICs, as further utilization of existing expressway-stocks is required in the future. The purpose of this study is to obtain practical suggestions for future of efficient IC development, considering differences in various socioeconomic conditions concerning the evolution of IC-interval for each route, analyzed using a simple theoretical standardization method. As a result, it became clear that it can be considered that the existing ICs development was basically being planned in a generally consistent way of thinking. On that basis, we examined characteristics of each route IC-interval, and clarified the characteristics at the beginning of service of the route, and of various additional IC development systems until today.
The purpose of this study is to show that the quantitatively relationship between experiences of traffic incidents and traffic accidents and human characteristics of senior drivers, because there is a necessary to figure out characteristics of traffic incidents to promote safety measures of senior drivers and to show possibility of being able to use traffic incidents data to analyze traffic accidents. To show the relationship considered subjective traffic incidents that senior drivers actually perceived, this study uses the result of the questionnaire survey with senior drivers as a target. This paper describes two findings regarding senior drivers depending on the results of three analyses. The first one is that drivers who have no confidence of their driving ability have higher possibility of perceiving traffic incidents than others. The second is that drivers who have experience of perceiving traffic incident have higher possibility of causing traffic accidents than others. From the findings, this paper suggests traffic accidents data that senior drivers actually perceived may be able to use for evaluating traffic accidents.
This study is aimed at statistically analyzing the detailed factors and mechanisms which might cause velocity drops in free flow condition. This study focuses on the influence of road alignment, structure and traffic characteristics upon the velocity changes of flow utilizing ETC 2.0 probe data with spatially and temporally higher resolution than the conventional data. The target section is between Kawasaki IC and Atsugi IC of Tomei Expressway including Yamato TN with heavy traffic jams frequently observed due to sag section. After a basic analysis using the contour diagram of speed profile, a regression analysis is applied for average speed and the estimated parameters suggest the significant influence of cumulative effect of up slope and merging and diverging points upon velocity variation. Finally Bayesian Network is applied for travel trajectories provided by ETC 2.0 probe data aiming at realizing the factors which might lead to higher probability of velocity drop.
In the European countries, new concept of dual use street called Shared Space was adopted in road space design. It’s a way of thinking that all traffic control devices have been removed as much as possible, road designs have been considered. Because of ingenuity of road space design, safety and attractive of road space have improved constantly. Also in Japan, social experiment and road space development based on the Shared Space concept have implemented. And, similar achievements to in Europe countries have been reported. So, the purpose of this study is to confirm effectiveness of Shared Space more multilaterally in Japan. Then we have investigated the awareness of pedestrians and drivers. This result suggests empirically that road space development based on the Shared Space concept might be effectiveness in Japan. The road space like a Shared Space cause more communication such as eye contact and greeting, cause more cooperative behavior such as deceleration and stopping, and improve attractive of road space.
The road traffic accidents are always a chronic social issue in terms of economically big loss. Meanwhile, the traffic accidents on Hanshin Expressway have been reduced on account of the various safety measures on the traffic accident-prone spots and the occasional supports to drivers. But it shows that there's a limit in the existing traffic safety actions as a lot of traffic accidents still occur. In this sense, new safety measures with a different point of view are required in order to decrease the number of traffic accidents. This study aims for contributing to reduce traffic accidents further. We suggest the new classification of traffic accidents through the traffic accident factor analysis using the quantitative and the qualitative accident data from the traffic accident database consisting of traffic accident data, traffic data, road structure data, weather data and safety measures data. The influence of traffic accident clusters on society is quantified and the appropriate safety measures for each cluster are proposed.