Volume 6, 2008

Vol. 6, No. 1, July 2008

Research papers

Number: 2007-15
Type: Research Paper (Best Scientific Papers at the 14th ITS World Congress Beijing 2007)
Pages: 3-10
Title: An Application of Intelligent Noise Filtering Techniques in Demand Forecasting for Carsharing Systems
Author(s): Hooi Ling Khoo (National University of Singapore)
Chau Ha Fung (Credit Suisse)
Qiang Meng (National University of Singapore)
Der-Horng Lee (National University of Singapore)

Received: 10/12/2007
Revised: 15/03/2008
Accepted: 16/03/2008

Abstract: This study deals with demand forecasting for the carsharing system with multi-station and flexible returning station and time. Neural network is employed as the simulation model to forecast the demand at each station at certain time period in the system. This study introduces intelligent filtering techniques as a tool to remove the noise of the data before it is fed into the simulation model. Two filtering techniques have been tested, namely outlier analysis and cluster analysis. Results show that outlier analysis is better compared to cluster analysis in enhancing the accuracy of forecasting model. This shows that proper choice of techniques is important to guarantee that the introduction of this extra procedure could improve the forecasting accuracy.

Keywords: Simulation, Data Mining, Demand forecasting


Number: 2007-17
Type: Research Paper (Best Scientific Papers at the 14th ITS World Congress Beijing 2007)
Pages: 11-19
Title: Prediction of DSRC Service Over-reach inside an Arched Transportation Tunnel
Author(s): Gilbert Siy Ching (Tokyo Institute of Technology)
Mir Ghoraishi & Navarat Lertsirisopon (Tokyo Institute of Technology)
Jun-ichi Takada (Tokyo Institute of Technology)
Itoji Sameda (Japan Highway Public Corporation)
Ryuji Soma (Nippon Expressway Research Institute Co. Ltd.)
Hironori Sakamoto (Highway Telecom Engineering Co., Ltd.)
Tetsuro Imai (Research and Development Center, NTT DoCoMo Inc.)

Received: 13/12/2007
Revised: 02/06/2008
Accepted: 13/06/2008

Abstract: Inside tunnels, the possibility of over-reach of radiated power from the Dedicated Short Range Communications (DSRC) service zone to the out-of-service zone is high, since the waves are confined in the tunnel space. To inspect this more carefully, wideband directional channel measurements were conducted inside an arched transportation tunnel, and the gain, angle-of-arrival and delay of each propagation path were estimated from the measured data. These propagation paths reveal that paths scattered from ground and sidewalk are the dominant factors that cause the over-reach of radiated power. This then suggests that the ground and sidewalk paths together with the LoS path can be used to predict the over-reach inside a typical transportation tunnel.

Keywords: DSRC, over-reach, tunnel propagation, wideband directional measurements


Number: 2007-04
Type: Research Paper
Pages: 21-27
Title: Preliminary Analysis on Link Travel Time for Probe-Based Estimation Method by Microscopic Simulation
Author(s): Qiang Li (Nagoya University)
Tomio Miwa (Nagoya University)
Taka Morikawa (Nagoya University)

Received: 02/04/2007
Revised: 03/08/2007, 01/11/2007
Accepted: 06/11/2007

Abstract: A set of travel time reports from probe vehicles is a sample. The adequate sample size required to estimate mean travel time of all vehicles (population) reliably has been studied in many literatures. However, in these literatures, the population is simply assumed as normal or approximate normal. In this paper, the properties of the population are discussed. The population is divided into three stages and the properties of the population in each stage are described in qualitative analysis and the description is verified by microscopic traffic simulation model. From this, some conclusions that are important to develop probe-based estimation method are made.

Keywords: Link Travel Time, Probe Vehicle, Population, Simulation


Number: 2007-03
Type: Research Paper
Pages: 29-36
Title: Study on the Cost-Effectiveness of a Probe Vehicle System at Lower Polling Frequencies
Author(s): Kai Liu (Kobe University)
Toshiyuki Yamamoto (Nagoya University)
Taka Morikawa (Nagoya University)

Received: 02/04/2007
Revised: 03/08/2007, 10/01/2008
Accepted: 21/01/2008

Abstract: One serious problem of continuous large-scale data collection with probe vehicle is the dilemma of balancing the cost economization and system reliability improvements. The polling frequency is found to be one of the major factors that determine the operation cost of a probe vehicle-based traffic data collection system. This paper focuses on evaluating the cost-effectiveness of a probe vehicle system at various space-based polling intervals, with the purpose of data collection on providing roadway travel time estimation at certain reliability. The proposed optimization framework concentrates on the least total operation cost through a combining consideration on the polling frequency and the required probe size, which gives a simple and valuable solution on the issue of cost-effective traffic data collection.

Keywords: Cost-effectiveness, Probe vehicle system, Polling frequencies


Number: 2007-10
Type: Research Paper
Pages: 37-45
Title: Risk Assessment of Intersection Safety Countermeasures with the Use of Field Data
Author(s): Ching-Yao Chan (California PATH Program, University of California at Berkeley)
Mikio Danno (Toyota InfoTechnology Center)

Received: 01/08/2007
Revised: 01/11/2007, 23/01/2008
Accepted: 24/01/2008

Abstract: In recent years, there have been world-wide interests in developing intersection collision avoidance systems. In such systems, computing, sensing, and communication technologies are utilized for the implementation of advanced driver assistance systems by issuing alerts to drivers in potential hazardous situations. To assess the effectiveness of proposed safety countermeasures, it is necessary to investigate whether the countermeasures can result in favorable and desirable driver responses. For the purpose of exploring design options and implementation issues of driver assistance functions, driver reactions can best be observed through the collection of field data in a real-world setting. This paper describes a study related to the collection, utilization and interpretation of field data. In addition, a criticality index function is proposed to quantify the safety risks in specific traffic scenarios. The availability of such risk index can be used to determine the safety impact of suggested collision avoidance systems.

Keywords: Driver Assistance Systems, Intersection Collision Avoidance, Safety Risk


Number: 2008-01
Type: Research Paper
Pages: 47-56
Title: Analysis of Driver Behavior based on Experiences of Road Traffic Incidents Investigated by means of Questionnaires for the Reducing of Traffic Accidents
Author(s): Masahiro Miyaji (Toyota Motor Corporation)
Mikio Danno (Toyota InfoTechnology Center Co. Ltd.)
Koji Oguri (Aichi Prefectural University)

Received: 22/01/2008
Revised: 24/04/2008, 30/05/2008
Accepted: 30/05/2008

Abstract: The number of persons injured due to Traffic Accidents in Japan has exceeded 1 million during each of the past eight years (as of 2006), and reducing the number of traffic accidents has become an urgent issue. We believe that reducing the opportunities for encountering traffic incidents, which may lead to traffic accidents, is an effective means of reducing the number of traffic accidents. Previous analysis of traffic incidents using drive recorders was conducted primarily to analyze the factors which cause traffic accidents and to analyze driver behavior. This study utilized a questionnaire investigation to collect examples of traffic incidents which occur during ordinary driving, analyzed the driver behavior and driver mental and physical states immediately before encountering the traffic incident, and identified driver characteristics which make traffic incidents more likely. We also conducted a comparison with the regression analysis results from previous research concerning daytime subjective sleepiness as a factor that is likely to lead to serious accidents. Based on these results, we propose a direction for further research concerning physiological signal-driven driving support systems that detect driver physiological signals in order to prevent traffic accidents.

Keywords: Driver Monitoring, Mental and Physical States, Physiological Signals, Regression Analysis


Number: 2008-11
Type: Research Paper
Pages: 57-65
Title: An Analysis of Effects of Trend Information upon Route Choice Behavior by In-Laboratory Experiment
Author(s): Mitsuhisa Tanaka (Graduate School of Engineering, Kyoto University)
Nobuhiro Uno (Graduate School of Management, Kyoto University)
Fumitaka Kurauchi (Department of Civil Engineering, Gify University)
Yoongho Ahn (Graduate School of Engineering, Kyoto University)

Received: 15/04/2008
Revised: 13/06/2008
Accepted: 13/06/2008

Abstract: This study focuses on the possibility that providing the information on short-term trend of traffic condition (trend information) with exiting travel time information might affect the decision-makings of travelers and lead to the enhancement in traffic control by information provision. As an initial step to confirm the effectiveness of trend information, this study conducts the in-laboratory experiment to obtain a kind of panel data of route choices under the provision of information. In this study the parameters of Mixed Logit Model are estimated in order to statistically analyze the influences of trend information upon decision-makings of respondents considering the accuracy of information. The basic findings obtained in this study are as follows. 1)There is a strong possibility that the trend information may significantly affect the decision-makings on route choices of respondents. 2)The influence of information upon the decision-makings of respondents may depend upon the accuracy of both travel time information and trend one. 3)Judging from the estimated parameters of standard deviation of travel time information, there must be the heterogeneity in the sensitivity toward the travel time information among the respondents.

Keywords: route choice behavior, travel time information, trend information, in-laboratory experiment

Vol. 6, No. 2, December 2008

Research Paper

Number: 2007-16
Type: Research Paper (Best Scientific Papers at the 14th ITS World Congress Beijing 2007)
Pages: 67-77
Title: Evaluation of Road Pricing Policy with Semi-Dynamic Combined Stochastic User Equilibrium Model
Author(s): Ryo Kanamori (Nagoya University)
Tomio Miwa (Nagoya University)
Takayuki Morikawa (Nagoya University)

Received: 12/12/2007
Revised: 07/05/2008
Accepted: 30/06/2008

Abstract: This study analyzes the effect of road pricing policy using a model that 1) incorporates trip generation (i.e. activity choice), destination choice, mode choice, and route choice; 2) considers variations in hourly traffic conditions, including queue evolution; and 3) approximately reproduces the trip chain along the time axis. An evaluation of road pricing policy in the Nagoya Metropolitan Area shows that the policy can improve the environment by reducing the number of car trips that are taken. At the same time, it greatly reduces the number of visitors to the city center by promoting a destination change and only a small shift from cars to railways.

Keywords: Road Pricing, Transport Demand Forecasting, Combined Stochastic User Equilibrium Model


Number: 2007-18
Type: Research Paper (Best Scientific Papers at the 14th ITS World Congress Beijing 2007)
Pages: 79-86
Title: Departure Time Distribution in the Stochastic Bottleneck Model
Author(s): Hao Li (Delft University of Technology)
Piet HL Bovy (Delft University of Technology)
Michiel CJ Bliemer (Delft University of Technology)

Received: 15/12/2007
Revised: 07/03/2008, 25/04/2008, 26/08/2008
Accepted: 26/08/2008

Abstract: This paper presents an analytical investigation of departure time choice under stochastic capacity using Vickrey’s bottleneck model. The deterministic bottleneck model of Vickrey has been extended with random capacities. It is assumed that travelers are fully aware of the stochastic properties of the travel time and schedule delays at all departure times that emerge from day to day due to random capacity. Based on the analytical analyses, consideration of random capacities and travel time reliability in the utility function appears to result in significant shifts in the temporal demand pattern. Travelers will depart earlier and departure flows become more spread over a longer time period. Long term equilibrium is achieved under stochastic capacities. These theoretical findings are supported by empirical findings of delays at bottlenecks. Correctly modeling departure time distributions under stochastic supplies over days plays a crucial role in the assessment of the network performance and in the evaluation of dynamic traffic management measures.

Keywords: Vickrey’s bottleneck model, departure time choice, stochastic capacity, travel time reliability


Number: 2008-08
Type: Research Paper
Pages: 87-95
Title: Photo-Realistic Driving Simulator using Eigen Texture and Real-Time Restoration Techniques by GPU
Author(s): Ryo Sato (Saitama University)
Shintaro Ono (The University of Tokyo)
Hiroshi Kawasaki (Saitama University)
Katsushi Ikeuchi (The University of Tokyo)

Received: 21/03/2008
Revised: 08/09/2008
Accepted: 30/10/2008

Abstract: Computer modeling of a large-scale scene such as a city is an important topic in ITS, with applications in driving simulation, car navigation, city planning, etc. Image-Based Rendering (IBR) is an effective method for presenting a realistic scene, where real images are stored as a database in advance, and a novel view can be synthesized by cutting and stitching images in the database. However, the large size of the image database in IBR causes serious problems in actual applications, requiring the use of compression techniques. We propose a compression technique based on eigen images combined with a block-matching technique to get a better result. We also propose a technique to uncompress the data on the fly by using a Graphic Processing Unit (GPU), allowing us to perform high-speed rendering without raising the load on the CPU. This technique is also promising as a means of achieving realistic driving simulation systems.

Keywords: Image compression, Driving Simulator, Image-Based Rendering, GPU, Omni-directional image


Number: 2008-09
Type: Research Paper
Pages: 97-104
Title: Road Information Gathering and Sharing during Disasters Using Probe Vehicles
Author(s): Noriko Kodama (Waseda University)
Yasunori Hada (University of Yamanashi)

Received: 01/04/2008
Revised: 18/07/2008, 04/11/2008
Accepted: 20/11/2008

Abstract: Although road information sharing is vital in disaster response, recent breakthroughs in information and communication technology have not yet resolved this important problem. In this study, the existing situation and problems encountered in road information sharing are overviewed. We discuss the characteristics and possible uses of probe vehicle data. Probe vehicle data provides information about roads that are likely to remain available. The travel time is numerically simulated with and without the sharing of road closure information among vehicles. The simulation results indicate that the probe vehicle data can be effectively used to gather regional information about available roads, and for reducing the travel time during disasters.

Keywords: Probe vehicle, Road information, Information sharing, Disaster response


Number: 2008-04
Type: Research Paper
Pages: 105-109
Title: Travel Time Estimation on Arterial Roads using Probe Data and Bayesian Network Learning
Author(s): Charitha Dias (Chodai Co., Ltd.)
Marc Miska (University of Tokyo, Institute of Industrial Science)
Masao Kuwahara (University of Tokyo, Institute of Industrial Science)

Received: 19/03/2008
Revised: 14/11/2008
Accepted: 27/11/2008

Abstract: In this paper we are introducing a self learning tool for travel time estimation in signalized urban networks based on probe data. The main feature of this tool is, that it can be applied with a basic network description instead of a detailed modeling of the network structure. We show how probe data can be utilized to train a Bayesian network to forecast the travel time on a route along an arterial road. In the conclusion we take a critical look on the limitations of such a system and possible extensions to increase its performance.

Keywords: Travel time estimation. Probe data, data learning, Bayesian network


Technical Note

Number: 2008-02
Type: Technical Note
Pages: 111-116
Title: MAS Model of the Level Crossing
Author: Ales Janota (University of Zilina)

Received: 14/02/2008
Revised: 28/05/2008
Accepted: 02/07/2008

Abstract: The paper introduces a new unpublished version of the multi-agent model of the level crossing system and summarizes research work that has been done since release of the previous concept model in late 2005. The multi-agent approach allows effective modelling of the complex control process of traffic flows from two different kinds of transport. The model respects basic function safety requirements and its graphic design truly corresponds to the Slovak/Czech-like road-rail interface. Code of the model was designed using the hybrid compiler/interpreter NetLogo 3.1.4. Through different initial settings traffic flows for railway and/or road traffic may be defined and different parameters calculated and observed based on simulation. Partial attention is paid to brief survey of newly implemented functions. Within conclusions the author also presents some further improvements and intentions of the future research.

Keywords: Multi-Agent System, Level Crossing, Traffic Flow, Function Safety Requirements, NetLogo