Faculty Profiles - NAKAMURA, Hideki

Papers - NAKAMURA, Hideki

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Analysis on the Variation of Left-turning Vehicle Spatial Trajectories Inside Intersections

ALHAJYASEEN Wael K.M., ASANO Miho, SUZUKI Kazufumi, NAKAMURA Hideki

Journal of the Eastern Asia Society for Transportation Studies Vol. 9 ( 0 ) page： 1543 - 1557 2011

Language：English Publisher：Eastern Asia Society for Transportation Studies

Although several safety countermeasures such as reforming intersection layouts have been implemented, methods to evaluate their effects prior to installation has not yet been established. One of the important safety issues at signalized intersections is the interaction between left-turning vehicles (left-hand traffic) and pedestrians/cyclists. This paper aims to analyze and model the trajectory variations of left-turning vehicles. Vehicle trajectories are collected at several signalized intersections with various traffic and geometric characteristics by video observations. The analysis reveals a significant variation in trajectories depending on intersection angle, number of exit lanes and vehicle type. For modeling individual vehicle trajectories and their distribution, the Euler-spiral-based approximation methodology is applied. Model validation showed that estimated trajectory distributions explain well the spatial maneuver of left-turning vehicles.

DOI： 10.11175/easts.9.1543

CiNii Research

Analysis on the Variation of Left-Turning Vehicle Spatial Trajectories Inside Intersections

Alhajyaseen Wael K. M., Asano Miho, Suzuki Kazufumi, Nakamura Hideki

Proceedings of the Eastern Asia Society for Transportation Studies Vol. 2011 ( 0 ) page： 309 - 309 2011

Language：English Publisher：Eastern Asia Society for Transportation Studies

DOI： 10.11175/eastpro.2011.0.309.0

CiNii Research

STUDY ON THE ESTIMATION OF SPEED-FLOW RELATIONSHIPS FOR DIVIDED TWO-WAY TWO-LANE EXPRESSWAY SECTIONS

UTSUMI Taisuke, HAMAOKA Hidekatsu, NAKAMURA Hideki

Journal of Japan Society of Civil Engineers, Ser. D3 (Infrastructure Planning and Management) Vol. 67 ( 3 ) page： 261 - 269 2011

Publisher：Japan Society of Civil Engineers

A divided two-way two-lane (TWTL) expressway crosssection was defined in the most recent update of Road Structure Ordinance in 2003. This novel structure is expected to contribute to saving building cost of rural expressways particularly with low traffic demands. However, since its speed performance is remained unclear, the expected target speed may not be realized under some road traffic conditions.<br> This paper therefore aims to analyze impacts of various conditions on speed-flow relationships of the divided TWTL expressway sections by using vehicle detector data, towards implementing the performance-oriented planning and design policy. After extensive analyses on several influencing factors that affect speed performance such as heavy vehicle ratio and precipitation, speed-flow relationships under different conditions are finally formulated. By using the proposed formulae, speed performance of the TWTL expressway sections can be verified at the planning and design stage of highways.

DOI： 10.2208/jscejipm.67.261

CiNii Research

A STUDY ON THE STOPPING CHARACTERISTICS OF KISS-AND-RIDE VEHICLES IN STATION PLAZAS

Journal of Japan Society of Civil Engineers, Ser. D3 (Infrastructure Planning and Management) Vol. 67 ( 5 ) page： 67_I_1079 - 67_I_1087 2011

Language：Japanese Publisher：Japan Society of Civil Engineers

Station plazas are important interchanges in the transportation network. However in Japan, their performance is reduced due to insufficient consideration of K&R behavior. Accordingly this study aims to analyze K&R vehicle stopping characteristics by investigating influencing factors such as facility configuration and plaza structure. Based on empirical data, the stopping position choice is modeled. Also different influencing factors are found for picking-up and dropping-off vehicles. Furthermore, a case study is conducted by simulation to represent the stopping position choice influenced by barrier or facility configuration.

DOI： 10.2208/jscejipm.67.67_i_1079

CiNii Research

A STUDY ON IMPLEMENTATION POLICY OF AUXILIARY PASSING LANE ON TWO-WAY TWO-LANE HIGHWAYS CONSIDERING FOLLOWER DENSITY

NAKAMURA Hideki, KOBAYASHI Masato, CATBAGAN Jerome L.

Journal of Japan Society of Civil Engineers, Ser. D3 (Infrastructure Planning and Management) Vol. 67 ( 3 ) page： 270 - 282 2011

Publisher：Japan Society of Civil Engineers

In this paper, a methodology to evaluate impacts of implementing auxiliary passing lanes on the qulity of service of two-way two-lane (TWTL) highways is developed, by adopting follower density as a measure of effectiveness. It aims to quantitatively esti mate the performance of traffic flows to be realized dependent on the passing lane length and its spacing and to provide suggestions as a design guide. Relationships between passing lane length, one-lane section length and follower density are formulated by modeling the simulation results based on traffic fl ow surveys. And possible combinations of minimum required passing lane length and its spacing required for achieving the target performance are indicated. Furthermore, the expected qulity of service of traffic flow under seve ral typical design policies of 2+1 lane highways are evaluated by applying this concept.

DOI： 10.2208/jscejipm.67.270

CiNii Research

REVIEW AND PERSPECTIVE OF HIGHWAY CAPACITY AND QUALITY OF SERVICE RESEARCH IN JAPAN

OGUCHI Takashi, NAKAMURA Hideki

Journal of Japan Society of Civil Engineers, Ser. D3 (Infrastructure Planning and Management) Vol. 67 ( 3 ) page： 217 - 229 2011

Publisher：Japan Society of Civil Engineers

The highway traffic congestion is one of the most important social and technical issues from the early days of motorization in Japan. Accordingly, the highway capacity has long been a major concern of traffic engineers, not only in research but also in practice, in order to alleviate the traffic congestions. Also, the concept of the quality of service of traffic flow and its proper understanding according to diverse conditions are crucial for implementing the performance-oriented highway planning and design schemes. This article therefore overviews the recent research works regarding highway capacity and quality of service particularly in Japan, after reviewing the state of the arts in bottleneck phenomena observed on Japan motorways and highways. And the future perspective of these research fields is discussed.

DOI： 10.2208/jscejipm.67.217

CiNii Research

EDITORIAL - TOWARDS PRACTICAL APPLICATION OF THE PERFORMANCE-ORIENTED HIGHWAY PLANNING AND DESIGN

NAKAMURA Hideki, OGUCHI Takashi

Journal of Japan Society of Civil Engineers, Ser. D3 (Infrastructure Planning and Management) Vol. 67 ( 3 ) page： 195 - 202 2011

Language：Japanese Publisher：Japan Society of Civil Engineers

Quality of road traffi c in Japan is still unsatisfactory as the road network cannot achieve the desirable performance corresponding to traffi c and access functions of roads yet, and there remain a lot of subjects to be resolved in terms of road design and traffi c operations. The existing road network should be gradually improved and restructured as cost-effective, high-performance one, however, the conventional highway planning and design methodology can be considered to hardly achieve it. For that, practical application of the "performance-oriented highway planning and design" policy is needed, which can flexibly adopt possible combinations of road design and traffi c operation schemes necessary for realizing target performance. In this article, for the special issue on "performance-oriented highway planning and design", its concept and research requirements are overviewed, as well as the structure of this issue.

DOI： 10.2208/jscejipm.67.195

CiNii Research

Unsteady Queue Discharge Characteristics of Shared Left-turn Lane at Signalized Intersections in Japan

CHEN Peng, NAKAMURA Hideki, ASANO Miho

Proceedings of the Eastern Asia Society for Transportation Studies Vol. 2011 ( 0 ) page： 300 - 300 2011

Language：English Publisher：Eastern Asia Society for Transportation Studies

In Japan, where vehicles travel on the left side of the road, the queue discharge rates of shared left-turn lane usually show comparable fluctuation, due to different departure characteristics of through and left-turning vehicles as well as interactions with pedestrians and bicycles. For a better evaluation of signalized intersections and then corridor performance, this study investigates stochastic queue discharge rates starting from shared left-turn lane and empirically explores its implications. Results show that efficient utilization of shared lane by through traffic can significantly improve discharge rate. At lower and higher pedestrian-bicycle volumes, discharge rates are relatively reliable. While at middle levels of pedestrian demands, more random arrivals and interactions lead to rather unstable saturation flow rate fluctuation. For the shared lane with a larger left turning radius, its discharge rates display a stable trend.

DOI： 10.11175/eastpro.2011.0.300.0

CiNii Research

Unsteady Queue Discharge Characteristics of Shared Left-turn Lane at Signalized Intersections in Japan

CHEN Peng, NAKAMURA Hideki, ASANO Miho

Journal of the Eastern Asia Society for Transportation Studies Vol. 9 ( 0 ) page： 1499 - 1512 2011

Language：English Publisher：Eastern Asia Society for Transportation Studies

In Japan, where vehicles travel on the left side of the road, the queue discharge rates of shared left-turn lane usually show comparable fluctuation, due to different departure characteristics of through and left-turning vehicles as well as interactions with pedestrians and bicycles. For a better evaluation of signalized intersections and then corridor performance, this study investigates stochastic queue discharge rates starting from shared left-turn lane and empirically explores its implications. Results show that efficient utilization of shared lane by through traffic can significantly improve discharge rate. At lower and higher pedestrian-bicycle volumes, discharge rates are relatively reliable. While at middle levels of pedestrian demands, more random arrivals and interactions between pedestrians and vehicles lead to rather unstable saturation flow rate fluctuation. For the shared lane with a larger left turning radius, its discharge rates display a stable trend. A comparative analysis between observed saturation flow rates, Highway Capacity Manual (HCM, 2000) and Japanese guideline (JSTE, 2007) estimations indicate both HCM and Japanese guideline usually overestimate the discharge rates in shared left-turn lane in Japan.

DOI： 10.11175/easts.9.1499

CiNii Research

Impacts of Channelization Islands on the Left-turning Vehicle Maneuvers at Signalized Intersections in Japan

Dang Minh Tan, Asano Miho, Nakamura Hideki

Proceedings of the Eastern Asia Society for Transportation Studies Vol. 2011 ( 0 ) page： 380 - 380 2011

Language：English Publisher：Eastern Asia Society for Transportation Studies

The number of pedestrian injuries and fatalities involved by left-turning vehicles (in left-hand traffic) at signalized intersections occupies a very large portion in traffic accidents. Installing channelization islands, e.g. raised islands or zebra marking islands atintersections is considered as one of the most important factors influencing on conflicts between pedestrians and left-turning vehicles. However, their impacts on vehicle maneuver have not been quantitatively analyzed. The objective of this study, therefore, is to quantitatively evaluate the impacts of channelization islands, on maneuvers of left-turning vehicles. Results of the analyses on turning vehicle maneuvers conclude that the use of raised island gives between one-and-a-half to two times greater impacts on the trajectory and the speeds as compared to the impacts of zebra islands. The use of zebra marking islands has low influence on the vehicle trajectory and the speed.

DOI： 10.11175/eastpro.2011.0.380.0

CiNii Research

Quality of pedestrian flow and crosswalk width at signalized intersections Open Access

Alhajyaseen W., Nakamura H.

IATSS Research Vol. 34 ( 1 ) page： 35 - 41 2010.7

Publisher：IATSS Research

Among various pedestrian facilities, signalized crosswalks are the most complex and critical ones. Their geometry and configuration including width, position and angle directly affect the safety, cycle length and resulting delays for all users. Existing manuals do not provide clear and rational specifications for the required crosswalk width under different pedestrian demand combinations and properties. Furthermore, they do not consider the bi-directional flow effects on crossing speed and time when addressing pedestrian flow at signalized crosswalks. However, quantifying the effects of such interactions on the behavior of pedestrian flow is a prerequisite for improving the geometric design and configuration of signalized crosswalks. The objective of this paper is to develop a methodology for estimating the required crosswalk width at different pedestrian demand combinations and a pre-defined LOS. The developed methodology is based on theoretical modeling for total pedestrian platoon crossing time, which consists of discharge and crossing times. The developed models are utilized to generate the fundamental diagrams of pedestrian flow at signalized crosswalks. A comprehensive discussion about the effects of bi-directional flow and various pedestrian age groups on the characteristics of pedestrian flow and the capacity of signalized crosswalks is presented. It is found that the maximum reduction in the capacity of signalized crosswalks occurs at roughly equal pedestrian flows from both sides of the crosswalk. By utilizing existing LOS thresholds for pedestrian flow at signalized crosswalks, the required crosswalk widths for various pedestrian demand combinations are proposed for implementation. © 2010 International Association of Traffic and Safety Sciences.

DOI： 10.1016/j.iatssr.2010.06.002

Open Access

Scopus

Estimating the Minimum Required Width of Signalized Crosswalks Considering Bi-Directional Pedestrian Flow and Different Age Groups

ALHAJYASEEN Wael K.M., NAKAMURA Hideki

Asian Transport Studies Vol. 1 ( 2 ) page： 181 - 198 2010

Language：English Publisher：Eastern Asia Society for Transportation Studies

Existing manuals do not provide clear specifications for the required crosswalk width under different pedestrian demand volumes and characteristics. However, optimizing crosswalk configurations including width is an important concern to improve the overall performance of signalized intersections. The objective of this paper is to develop a methodology for estimating minimum required crosswalk width at different pedestrian demand volumes considering bi-directional flow and different pedestrian age groups. The developed methodology is based on modeling total pedestrian platoon crossing time which consists of discharge and crossing times. Discharge time is modeled by using shockwave theory while crossing time is modeled by applying aerodynamic drag theory. The developed models are then calibrated for crosswalks with mainly elderly or pupil pedestrian platoons. A set of criteria based on pedestrian crossing speed is developed to identify the minimum required crosswalk width. Finally, different required crosswalk widths are proposed for different pedestrian demand volumes and directional split ratios considering the effects of pupil and elderly pedestrian platoons.

DOI： 10.11175/eastsats.1.181

CiNii Research

An Improved Follower Recognition Procedure to Estimate Follower Flow-Based Quality of Service Measures

CATBAGAN Jerome, NAKAMURA Hideki

Journal of the Eastern Asia Society for Transportation Studies Vol. 8 ( 0 ) page： 1822 - 1837 2010

Language：English Publisher：Eastern Asia Society for Transportation Studies

For a follower-based service measure to be effectively used for two-lane highway quality of service evaluation, a more reliable follower identification procedure is necessary. Current follower recognition methodologies are based on single critical headway values that may not accurately identify followers since they do not take into account the randomness of preferred tracking headways and drivers' desired speeds. This paper presents an improved, probability-based follower identification methodology that takes both of these factors into account while also considering their variability across different driving conditions. The calculated follower percentage and follower density values were compared with those estimated using the 3-second threshold suggested by the HCM. The proposed methodology estimated more followers, particularly during periods of heavy flow, highlighting the inability of using a single headway value to correctly identify followers. The resulting follower counts have been normalized, making it possible to theoretically identify followers at any given time or driving condition.

DOI： 10.11175/easts.8.1822

CiNii Research

An Improved Follower Recognition Procedure to Estimate Follower Flow-Based Quality of Service Measures Reviewed

Catbagan, J.L. and Nakamura, H.

Proceedings of the Eastern Asia Society for Transportation Studies Vol. Vol. 7 page： 16 pages in CD-ROM 2009.11

*Modeling and Analysis of Pedestrian Flow at Signalized Crosswalks Reviewed

Alhajyaseen, K.M.W. and Nakamura, H.

Vol. Vol.26 page： 611-620 2009.11

Estimating the Minimum Required Width of Signalized Crosswalks Considering Bi-directional Pedestrian Flow and Different Age Groups Reviewed

Alhajyaseen, K.M.W. and Nakamura, H.

Proceedings of the Eastern Asia Society for Transportation Studies Vol. Vol.7 page： 16 pages in CD-ROM 2009.11

Estimation of Crosswalk Width to Minimize Cycle Length at Signalized Intersections Reviewed

Alhajyaseen, Wael K. M. and Nakamura, H.

Proceedings of the Eleventh International Summer Symposium, JSCE page： 213-216 2009.9

Traffic Signal Control Optimization from the Viewpoint of Emission at Isolated Intersections

Ma, D. and Nakamura, H.

Vol. No.39 page： 4ページ，CD-ROM 2009.6

*Considering Travel Time Reliability and Safety for Evaluation of Congestion Relief Schemes on Expressway Segments Reviewed

Mehran, B. and Nakamura, H.

IATSS Research Vol. Vol.33 ( No.1 ) page： 55-70 2009.6

幹線街路における沿道アクセス機能に応じた旅行速度性能曲線の定式化

早河辰郎・中村英樹

土木計画学研究・講演集 Vol. No.39 page： 4ページ，CD-ROM 2009.6

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