It is expected to control traffic light safely, especially at inter-green periods. Recently, countdown-type traffic signals for vehicles that are contributory to make appropriate judgments have been installed positively in Asian countries. In this study, we conducted a questionnaire survey and observed surveys via video cameras at signalized intersections with those types of traffic signals installation in Turkey. Analyzing the effect of the traffic signal from the viewpoint of users' consciousness, it was shown that users' satisfaction is improved and driving rage is dropped by the countdown display. Furthermore, it was also found that start-up delay is reduced and risky behaviors at inter-green periods are decreased by the signal, but at the same time the inadequate signal parameter settings may induce risky behaviors in spite of the countdown-type traffic signal installation.

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Including both transportation supply and demand management (TS-DM) measures underpins the development of an effective transportation management strategy. One may consider transportation infrastructure provision as the supply; whereas the traveling public as the demand, subject to demand management measures which are often introduced as a separate policy tool, distinct from supply management. Nevertheless, synergy can be achieved in solving congestion problems when TS-DM strategies are developed jointly in an integrated manner. This paper develops a bi-level formulation in determining the time-dependent TS-DM strategy. The interactions between TS-DM strategy and residential/ employment location choices are studied and comparisons between the mixed TS-DM strategy and traditional pure demand management are made. With a small network example, we demonstrate that the integrated TS-DM strategy is a promising way of designing and managing transportation network over time, creating a win-win situation between network operator and road users.

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Travel time is important information for network measurement and ITS applications. Recently number of arterial road travel time research raised has symbolised the importance of the research field. The shortage of travel time data and uncertain of signal settings are the two major challenges of arterial travel time research. The research adopts SCATS data and micro-simulation techniques to overcome the problems. In terms of traffic data, SCATS provides detailed traffic signal data and volume data meanwhile micro-simulation produces various detailed outputs for developing travel time prediction model. The result demonstrates that the developed travel time prediction model has the ability to provide good accuracy travel time results on arterial roads. The following research will focus on the extension of the model to deal with over flow travel time prediction.

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The cost and capacity of the communication between probe vehicles and the operation center impose restrictions on the number of probe vehicles and thus it is expected that reliability of probe reports can be obtained by relatively small number of probe vehicles. Travel time on a signalized link is a multi-peak distribution because there are several subgroups divided by turning movements and intersection delay at downstream. When sample size is small, sampling error arises and it is difficult to estimate population mean using sample mean directly. In this paper, the sources of sampling errors are discussed and an estimation method that minimizes the effect of the sampling errors are proposed. The result shows that performance level of a signalized link can be estimated reliably using the proposed method and small size sample.

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The application of micro simulation traffic modeling and analyzing software has been widely spread in many countries, including the developing countries. Before that, many developing countries have been used micro analytical software, for example aaSIDRA. It seems it is more difficult to use micro simulation software in developing countries due to there are more complex problems compared to developed countries, as the models were developed based on the travel behavior of the country. A study to model and analyze a signalized intersection has been undertaken in Padang, West Sumatra, Indonesia. It used CUBE Dynasim, a relatively new micro simulation software, and aaSIDRA. Throught the application of the two models, it has been found that CUBE Dynasim tends to generate lower approach flows compared to the real data while aaSIDRA generates higher lane capacity than the demand. Public transport arrival rate and stop time were reduced with by 10 percent incrementally in order to investigate this case. However, CUBE Dynasim still generates traffic flow which is below the real data.

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The application of micro simulation and analytical software has contributed significantly to the development of new and existing transport systems. However, it seems that the successfulness of the software could be different when used in different countries, particularly when the software is newly developed. It is due to the different of local conditions. A study has been undertaken in investigating this issue. Two signalized intersection located in different countries, in this case, Adelaide in South Australia and Padang in West Sumatra-Indonesia, have been used as cases in modeling and analyzing by using CUBE Dynasim and aaSIDRA. It resulted in some interested findings. For instance, CUBE Dynasim tends to generate the same output as aaSIDRA and match with the real data for intersection located in Adelaide. However, it is different for another intersection in Indonesia. The possible causes are related to the local infrastructure and travel behavior conditions and the simulation factors used by CUBE Dynasim.

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This paper presents models to predict freeway link travel time in multiple periods. The relationships between traffic measures and average link travel time from simulation were explored using the Generalized Additive Model (GAM), a nonparametric regression technique. Parametric models to predict freeway link speed were then developed based on the relationships discovered by the nonparametric model. The models were developed on a set of simulation data and tested on another set of simulation data. The root mean square errors (RMSE) of the model developed to predict link travel time at current time-step were 88.63, 6.88, 2.38 seconds for morning peak hours, off-peak hours, and afternoon hours, respectively. The RMSE of the model to predict link travel time at 5, 10, 15 minutes forwards were 91.20, 101.86, 122.08 seconds, respectively.

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This study aims to establish new assessment index to comprehensively assess the service level of the road by areas considering current qualitative method and quantitative method together using a structural equation model. The results of the study are as follows. In case of Gangnam-gu, traffic flow, utilization behavior, signal control, maintenance and management, road design and information and others were found in order as the indexes, and for Seongdong-gu, maintenance, information and other, traffic flow, signal control, road design and utilization behavior were found in order as the indexes. Based on the results of this study, there were differences in the recognition of the users for the service provided regarding the operation of the road and the facilities according to the areas. In the respect of the execution of traffic policies, it is necessary to establish appropriate measures to reflect the recognitions of the service users by areas about the quality of the services

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A radial basis function neural network (RBFNN) model is employed to predict the short-interval (within 15-minute) traffic series, including flow, speed and occupancy, which are measured in different time intervals, time lags, dimensions of state space, and times of day. Aside from describing entirely the methodology of RBFNN, the paper also uses two deterministic functions to test prediction power of the model. A field study with flow, speed and occupancy series directly extracted from two dual-loop detectors on a freeway of Taiwan is conducted. The results reveal that the predictive accuracies for different short-interval traffic dynamics by RBFNN model are quite satisfactory. The predictive accuracies can be affected by the means of representing traffic time-series data in terms of time intervals, time lags, dimensions of state space, and times of day.

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Signal control and route guidance jointly influence traffic flow in time and space. Firstly, the conceptual structure of combined signal control and route choice (CSCRC) was analyzed. Then, the mathematical models of CSCRC were summarized. Link travel time function and signal control policy have significant influence on solution uniqueness and convergence of CSCRC model. Simulation-based method can allow more complex interactions, therefore win real value than travel time formula. Modified iterative simulation and assignment procedure is built, in which road is discretized by Cellular Automata, traffic flow dynamics is represented by Cell Transmission Model, signal setting is optimized by Hybrid Genetic Algorithm. For toy network, the algorithm converges to stable solution.

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Many countries try to improve a traffic design on the intersection to make it safer as a traffic safety is more concerned on the traffic system. A near-side traffic signal has been recently introduced to many countries for the traffic safety. However, the efficiency of an intersection seriously goes down according to the location of a near-side signal on existing far-side traffic system, which is caused by wrong visibility of driver and extended distance to cross intersection. Both efficiency and safety should be considered on the improvement of intersections. On this study a control delay is used as the efficiency of intersections and it is researched what kinds of factors and how much they are influenced by the location of a signal device. Various analyses estimate the changes of traffic conditions on installation of near-die signal on this study.

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Motorcycle traffic has attracted little interest in the past, despite the reported increase in motorcycle ownership in many countries. Saturation flow and vehicle equivalence factors such as PCU values are two of the most important parameters characterising the traffic flow at signalised junctions. The investigation of these parameters facilitates a better understanding of traffic dominated by motorcycles. This paper introduces a new method to study the variation of saturation flow and vehicle equivalence factors. MCU values have been applied instead of the conventional PCU values. Five regression models were derived to describe the variation of saturation flow in three traffic compositions, including (1) motorcycles and straight-on cars, (2) motorcycles and cars making three movements (right, left and straight-on) and (3) all vehicle types making three movements. The paper also assesses the difference between two approaches of counting vehicles: one based on 4s periods during green time; the other based on the signal cycle. MCU values were estimated for different vehicle types making different turning movements.

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The knowledge of traffic operation of motorcycles is too little compared to the development of motorcycles in Southeast Asia. This study addresses a model framework of motorcycles' acceleration/deceleration at signalized intersections. Different from previous researches, which are associated with the static strip-based approach for referring motorcycle positions, a new technique, so-called dynamic motorcycle lane, is developed. Then, motorcycles' deceleration and acceleration are treated similarly to cars' by applying deceleration and acceleration models with some modifications. Two regimes in the deceleration and acceleration models are proposed: free-regime and following-regime. At every observed interval, the particular regime is specified by the longitudinal threshold distance. Finally, a case study is introduced to estimate the parameters of proposed models using microscopic traffic data collected at some intersections in Vietnam.

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Critical Gap Acceptance procedure is still widely used for estimating capacity of unsignalised intersection. In Malaysia, the critical gap acceptance is still being used as in the existing guideline for unsignalised intersection (Arahan Teknik (Jalan) 11/1987). However, the use of the gap acceptance procedure does not take into consideration the mixed traffic flow condition prevalent on Malaysian road. In this study, critical gap acceptances under normal saturation flow conditions were estimated for unsignalised T-Intersection in Malaysia using the Maximum Likelihood Method. The results indicate that there are significant differences between the critical gap of passenger cars and motorcycles. In this study, the composite critical gap that takes into consideration the differences in traffic compositions were proposed. The composite critical gap enables the use of single representative gap acceptance value for estimating capacity of unsignalised T-intersection based on Malaysian traffic condition.

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Traffic behavior of pedestrians' signal disregard gave rise to the increase of traffic accident and the decrease of the capacity of intersection in Nanjing, China. The traffic behavior at three kinds of typical crosswalks: signalized intersection crosswalk, single road intersection crosswalk and single road intersection button crosswalk was collected by using video camera and analyzed under different traffic conditions in the term of the proposed factors: vehicle traffic, headway, saturation degree, length of red light, ratio of red light and crosswalk length. The results showed that there were stronger positive correlation of signal disregard with headway; and stronger negative correlation with vehicle traffic volume, saturation degree, length of red light, the ratio of red light and crosswalk length. The ratio of signal disregard was higher at signaled intersection crosswalks across major highway while that at minor highway was lower.

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A roundabout is an alternative type of junction control that reduces delay under low traffic demand. Conditions under which they are advantageous in terms of capacity and delay have been already shown in existing researches. However, the implementation of roundabouts is likely to be negatively evaluated, particularly in Japan; due to safety reasons since traffic conflicts are inevitable when merging. In this paper, a methodology for the performance evaluation of at-grade junctions considering a trading-off relationship between delay and vehicular conflicts is proposed. The performance of signalized intersections and roundabouts are also compared by applying this methodology. As a result, it was found that roundabouts are still more advantageous than signalized intersections when approaching traffic volume is less than 500 vph, even though not only delay but also conflicts were taken into account as evaluation indices.

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Recent research has suggested that the discharge rate of traffic across the stop-line of signalised intersections is not constant (a conventional assumption when deriving saturation flow), but varies over the green time. Different studies have shown very different patterns of variation, but the reasons for these differences have not been fully explained. This study firstly compares previous results studying this variability and then attempts to explain why different patterns were produced by different situations. Then, another study is undertaken in traffic dominated by motorcycles also presented. It appears that the pattern of the discharge rate at signalised intersections depends on degree of saturation, traffic composition and types of signal control. Furthermore, it also seems that built-up time of discharge rate depends much on the proportion and manoeuvrability of the predominant type of vehicles at the head of the queue. Finally, the impacts of these unconventional patterns on the optimisation of signal timings are discussed through a practical example.

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This paper introduces some applications of travel time based performance measures and mainly the travel time reliability as a measure of performance. In this research, operational conditions of two different segments of an intercity expressway are evaluated and compared by using travel time based performance measures. While Buffer Time Index and Travel Time Index are used to evaluate travel time reliability and congestion, it is observed that travel times are more reliable during off-peak periods, whereas unreliability dramatically increases during the peak periods. Additionally, travel time reliability varies from time to time according to demand fluctuations and traffic influencing events. Finally, highway segments are found to be more susceptible to disruptions caused by traffic influencing events once congestion starts to build up.

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This study analyzes the impacts of the effective space on speed of various vehicles categories, dynamic motorcycle unit and mean stream speed under mixed traffic conditions on urban roads. Data was collected at three link roads of streets, namely Cau Giay, Hang Bot and Nguyen Luong Bang street in Hanoi. This study estimated the relationship between speed and effective space associated with various categories of vehicles. Dynamic Motorcycle Unit (DMCU) values were calculated and suggested that the impacts of space occupancy of vehicles on mean stream speed should be given special consideration. Different from projected rectangular area on ground, the factor for estimating area of vehicle occupying on ground as the required space, the boundary around vehicle including intersection area from other vehicles, is introduced to reflect DMCU more dynamically and accurately.

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This paper proposes a methodological framework for developing a real-time intelligent decision support system for urban traffic congestion emergency response. To support real-time decision making, the system is required to have the capability to provide an efficient organization of input data and inferred knowledge from all kinds of data sources so as to guarantee the adaptability to changes and the reusability for different congestion situations. For this requirement, we attempt to combine data warehouse with data mining methods in building the framework. Data warehouse provides a well-organized information source for traffic congestion dispersion by means of data collection, analysis, disposal and storage. Furthermore, data mining techniques deal with the set of mixed numeric and non-numeric congestion data and information. In this way, knowledge that represents cause-and-effect dependencies among the congestion attributes are extracted.

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In this paper an attempt is made to study the suitability of different available cellular automata (CA) based models for mixed traffic. CA model structure is modified to incorporate typical mixed traffic characteristics. Different CA updating procedures have been used with the modified CA structure to know their suitability for modelling mixed traffic. Detailed parametric studies are carried out to understand the ramifications of modified CA structure. From the parametric studies carried out, Knospe's brake light model (Knospe 2000) along with the modified CA structure, found to be useful in modelling mixed traffic. Using this new model, influence of slow vehicles such as trucks on the traffic stream is studied.

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This study assessed the need for traffic signalization from the perspective of local government units .by considering the issues, concerns and experiences revealed by the 23 LGUs outside Metro Manila, Philippines. Most of the cities are thickly populated. Majority of them are first class cities wherein there is a continuous increase in the number of registered motor vehicles every year. The levels of necessity and attainment of objectives for traffic signalization are very high and high, respectively. They tapped the expertise of the Traffic Engineering Center, Traffic Engineering and Management, and the academe for the conduct of traffic engineering studies. Correlative analysis was used in this study. There is a significant relationship between the consultation which was administered by LGUs and the level of attainment of objectives for signalization. The researchers recommend policy formulation of the guidelines in the implementation of traffic signalization among the local government units and agencies concerned.

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Most Algorithms for detecting incidents have been developed under the premise that the congestion must happen whenever an incident occurs. For the reason, the performance of algorithm could not be guaranteed in case the congestion does not happen due to the traffic operations of low flows despite the occurrence of an incident. This paper is to propose a new diagram that can reliably detect the incident under the various conditions of traffic operations including a low volume state. Compared to the McMaster Algorithm, the newly proposed diagram is tested with three different cases that the incident occurs in the traffic operations with the low volume state, the relatively high volume state, and the recurrent congestion section. Evidently, the new diagram shows a capability to identify the flow characteristics of incident for all the three cases.

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The authors are currently investigating the applicability of the operation policy, commonly applied at signalized intersections in Germany, for Japanese signalized intersections. As an initial step, this study analyzed traffic characteristics and driver behavior at several typical German and Japanese intersections to understand the impacts of such policy on them. The results showed that German intersections had significantly lower starting response time (SRT) and start-up lost time (SULT), which was due to the sequence of signal indications. However, no apparent variations existed in saturation flow rate (SFR) and lost time in amber (LTA). Left turners at German intersections tended to be more aggressive in choosing suitable gaps, indicated by critical gap and 1/PET values. Moreover, longer all-red clearance interval and gap adaptive control seemed to encourage aggressive pass. Lower stop-line crossing during amber (SCA) and red light violation (RLV) rates at German intersections were attributed to multiple factors.

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This paper aims to develop rolling grey forecasting models (RGM) to predict short-term traffics. Two types of RGM models are developed and compared: RGM(1,1) and RGM(1,N). To investigate and validate the accuracy and applicability of proposed models, two time horizons of short-term traffics of 1-minute and 5-minute are applied, respectively. For comparison, two commonly used short-term traffic prediction models: statistical time-series model (ARIMA) and artificial neural network (ANN), are also developed. The accuracies in term of mean absolute percentage error (MAPE) of various rolling intervals (4-8 intervals) and prediction periods (1-5 periods) of the proposed model are also compared. The results show that both of RGM(1,1) and RGM(1,N) perform better at fewer rolling interval and prediction period. Besides, RGM(1,6) remarkably outperforms in predicting three traffics, followed by RGM(1,1). Obviously, the performances and applicability of proposed RGM models are validated.

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This paper proposes refined cellular automata (CA) rules, including anticipation effect, slow-to-start, lane change, and interaction among vehicles to explore the fundamental traffic features. Generalized definitions of traffic variables, in spatiotemporal sense, and a new concept of common unit (CU) for gauging non-identical vehicle sizes and various lane widths are presented. The simulation experiments are tested on a two-lane freeway context. The effects of both stationary and slow-moving bottlenecks on global traffic are also examined. Vehicular trajectories, flow-occupancy, and spatiotemporal traffic patterns under deterministic and stochastic conditions are displayed. The results reveal noticeable traffic patterns with free flow, wide moving jam and synchronized flow phases. This study has demonstrated that the proposed refined CA models are capable of capturing the essential features of traffic flows which were also found in previous works.

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Chaos represents a condition that seems disorderly but regular in nonlinear and dynamic system. The application of chaos analysis is widespread on various field, either is in the traffic flow of the road. The motorcycle traffic flow at mixed traffic might also exist chaotic characteristic, especially when the relationship between different traffic parameters is disproportioned and disorderly. The motorcycle traffic at mixed traffic can be inferred and seen as a chaotic and dynamic system. Therefore, chaos theory is employed to analyze the mixed traffic characteristic with motorcycle and to demonstrate that the variables of motorcycle flow exists chaotic phenomenon. Finally, the comparison of pure and mixed motorcycle flow on attractor dimension can infer the complicacy exist in pure internal motorcycle traffic flow.

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The objective of this study is to develop a data quality evaluation method for managing the quality of vehicle detection data. For this purpose, we proposed a methodology for quantifying the accuracy, completeness, validity, timeliness, accessibility and coverage of vehicle detection data suggested by Battelle in the U.S. In addition, we developed a computer program that implemented vehicle detection data processing and evaluation. The developed computer program is composed of data processing module, data evaluation module and data service module. The developed computer program was applied to the traffic data collected from the expressways of Korea Highway Corporation in Korea. The developed data quality evaluation program was found to quantify data quality adequately in general. In addition, the overall quality of vehicle detection data was analyzed to be satisfactory.

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The purposes of this study were to investigate accuracy and reliability of travel time information and to assess the effectiveness of probe vehicle in providing travel time information under various traffic conditions. Paramics V5 was used to generate travel time data on a hypothetical network. Average travel time on links and routes were analyzed for various percentages of probe vehicles and compared to the true average travel time using bootstrapping technique. Results indicate that the plots of probe vehicle average travel time versus true average travel time for link and route case agreed well. However, travel time from probe vehicles is less accurate when traffic is congested. A case study was carried out to consider travel time between Origin-Destination. The quality of travel time not only depends on the percentage of probes but also the traffic conditions.

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The effects of heavy vehicles become more pronounced in two-lane highway facilities with passing restrictions since vehicles in a platoon do not have any other choice but to follow the leaders' choice of speed, which is usually below their desired speed levels. Furthermore, platoon lengths are expected to be longer than usual, affecting level of service indicators such as follower density and average travel speed. This study aims to make a preliminary analysis of the influence of heavy vehicle on such facility types in Japan. Detector data were analyzed for two different time periods - peak and weekday. The speed of heavy vehicles has a direct effect on follower speed and follower density was found to become more sensitive to heavy vehicle percentage as flow rate increases. Average speed was also found to be more sensitive to heavy vehicle presence on upgrades, especially during the evening period.

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The high increase of motorcycles in developing countries makes motorcycles traffic needs a special treatment; otherwise capacity at an intersection are sacrificed. This is because most accident involved motorcycles, and intersection capacity decreased due to improper behavior of motorcyclists. Therefore, the intention of this study is to investigate the behavior of motorcyclists and to find out a better solution that may increase intersection capacity. A field study was carried out at an intersection to perform a proposed measure when motorcycles exist at the approach of an intersection. Results of the experiment showed that the behavior of motorcyclists can be influenced by a measure that increases intersection capacity. This solution may be useful to be adopted in some similar countries in treating motorcycles.

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Traffic demands are sharply influenced by the time and day of the week regarding roads and station plazas. If it is possible to change the number of traffic lanes or the usage of road flexibly according to traffic demands, the limited road space can be used effectively and an efficient road operation can be managed. Furthermore, it can be thought to contribute to the improvement of user convenience and safety. The authors have developed a traffic marking system with high brightness light emitting diode named "Lane-Lighting-System". This system realizes the use of the above-mentioned road efficiency by changing traffic markings in accordance with traffic demands synchronizing with IT. In this paper, an outline of "Lane-Lighting-System" is introduced and its applications for roads, tunnels, station plazas and parking areas are proposed.

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This paper presents a traffic study in an urban area. The locale case is the unsignalized intersection along the national highway in Urdaneta City, Pangasinan, Philippines. There are 27,654 vehicles that traverse the unsignalized intersection during the fourteen hour period or with a flow of 1976 vehicles per hour. The peak hour was observed to be at 11-12 in the morning and 5-6 in the afternoon/night time. Majority of the transport modes that traverse during the mentioned peak hours are cars (e.g. automobiles, tricycles). Uncoordinated movements of the pedestrians along the national highway create conflicts between vehicles and pedestrians. There were ten accidents experienced in the year 2003. Most of them were experienced during nighttime. The information gathered is a significant input in the transportation planning process between LGU and Planners if the existence of traffic study in urban areas is to be considered.

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In this paper, the quantitative analysis of the congestion easing measures of acceleration lane length at merging sections was done by using our micro-simulation model for describing the traffic flow behavior in the merging sections in highways is proposed. By numerical simulation experiments, it was proven that when the main lane traffic volume was less, the effectiveness of acceleration lane length was good, and vice versa.

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In Japan, large signalized intersections often have quite long cycle times that may affect the environment and users' psychology. For cycle-time reduction, it is necessary to develop a new methodology to design intersections. One practical method can be considered as two-step crossing system with pedestrian refuges. By using a comprehensive simulation model that can deal with both pedestrians and vehicles, we checked the effect of two-step crossing system and short cycle times. As a result of the simulation, we found that cycle-time reduction is effective for both pedestrians and vehicles unless the vehicular traffic flow is heavy. Finally, we proposed a guideline for signalized intersection designing to design intersections that are safer and more efficient in traffic for both pedestrians and vehicles.

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Drivability is one of important factor for evaluation of level of services on roads network. So that "Drivability Map"was produced by Ministry of Land, Infrastructure and Transportation Government of Japan in 2006. This paper aims to investigate drivers' evaluation of "Drivability Map" based on results of questionnaire survey conducted in 2006. Validity of drivability ranks which is used in "Drivability Map" is also confirmed through driving experiment. Furthermore present roads network in Japan is evaluated from viewpoint of drivability, and several problems are presented. Differences of density of roads network between Japan and the United Kingdom are investigated from perspective of drivability.

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The authors tested effects of retro-reflecting performance for signs by driving under foggy condition. The tests were conducted on a road in service under four visibility conditions: daytime clear, daytime dense fog, nighttime clear, and nighttime dense fog. Two types, incorporating wide-angle prism retro-reflective and encapsulated-lens retro-reflective materials are used for testing visibility targets. Drivers drove a test car under free-flow condition and cued an experimenter in the back seat upon recognizing the warning sign and again upon determining its meaning. Visibility and legibility distances in daytime dense fog and nighttime dense fog tended to be greater for the signs incorporating wide-angle prism retro-reflective material than for signs incorporating encapsulated-lens retro-reflective material. The findings demonstrate that installing traffic signs with high retroreflectivity can contribute to driving safety by improving visibility and legibility under fog.

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This study creates an adaptive data fusion procedure to represent the sequential forecast of accident duration. This procedure includes two Artificial Neural Network-based models. Model A is used to forecast the duration time at the instant of accident notification while Model B provides multi-period updates of duration time after the moment of accident notification. These two models together provide a sequential forecast of accident duration from the accident notification to the accident site clearance. With these two models, the estimated duration time can be provided by plugging in relevant traffic data as soon as an accident is being notified. Through the feature composition approach, the number of inputs can be decreased while the relevant traffic characteristics are preserved.

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Questions of location, method, or effectiveness are the prime focuses of academic research about traffic improvement project. However, economic, political, administrative, and product concerns are often other aspects of importance when new or innovative traffic control devices (ITCD) are planned for installation to relieve safety problem or provide traffic information to road users. This research develops a procedure of three-staged fussy analytical hierarchical process (FAHP) to support the appraisal of where and when to install those devices besides the warrants of MUTCD. This research reveals that the factors concerned follows the order of 1.effectiveness, 2.cost and financial resource, 3.location and environment, 4.product capability, 5.possible political concerns, and lastly, 6.administrative endeavor. After completion of the criteria evaluation, 5 kinds of ITCD were used to test the model.

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Red light violation by motorcyclists is common in Indonesia. Therefore a study on this behaviour is essential. Observations were made on an intersection approach in Jakarta on 4 hourly observations at 5.00, 8.00, 12.00 and 15.00. Two types of violation were found, (1) at the beginning of red and (2) at the end of red. The type 1 was dominant during the early morning observation, whilst type 2 was dominant during the other three observations. The analysis shows that the higher the degree of saturations (Q/C) the higher the rate of type 1 violation and the lower the Q/C the higher the rate of the type 2 violation. Higher Q/C encourages motorcyclists to wait their turn in front of stop line and using gaps during the inter-greens. Lower Q/C allows a higher speed thus enables the use of the amber time or even all red time to cross the intersection.

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This paper presents traffic accident models of toll roads in the Greater Jakarta Area. The Negative Binomial modelling technique was used to model the frequency of accidents. Single vehicle multiple vehicle accidents were modelled separately and the results summed to provide an overall model. These models showed that the relationship between accidents and traffic flow can be described by U-shaped curves which were created using data from sets of dual-2, dual-3 and dual-4 toll roads. The dual-2 and dual-3 models were skewed to the right and the dual-4 model was skewed to the left indicating that high traffic flow conditions were associated with high numbers of accidents on dual-2 and dual-3 toll roads and low number of accidents on dual-4 toll roads. The modelling reveals that the dual-3 toll roads are the safest type in terms of accidents per kilometre.

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This paper describes the effect of geometric features on the risk of accidents on the Indonesian toll roads. Variables that were evaluated are: lane width, interior and exterior shoulder widths, median width, bendiness in terms of degrees per kilometre, presence of safety fences and street light, horizontal curve and terrain. The accident prediction models were constructed through homogenous one kilometre length using the negative binomial error structure. Accident risks were derived through the elasticities of each significant variable. It was found that lane width of 3.75 m, interior shoulder width of 0.70 m and exterior shoulder width of 3.00 m are associated with low accident risk for dual-2 toll roads. Lane width of 3.60 m, interior shoulder of 1.50 m and exterior shoulder width of 3.00 m are the best traffic performance for dual-3 toll roads. Safety fences should be provided regardless the median width.

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A model is developed for collision risk estimation in air traffic control system, which resolves the problem of the collision risk assessment of the recent ATM system. It is a systemic model, in contrast to the old models, in which the defensive barrier (STCA/TCAS) and human factors are modeled and the focus is on systemic analysis. The collision event tree is used to calculate the collision risk. This model makes it straightforward to see what leads to collision, and easy to understand the roles of the main parameters. It is a good starting point for the incorporation of defensive barrier and the human factors.

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This paper initially studies inverse problems of collision risk models, which computes the safe space through establishing a model under the condition of a given safe target level. First we improve models of collision risk models existed on the parallel route, and get cross-track, along-track and vertical safe separation computing the improved models. Then we establish the iterative arithmetic of models and simulate them on three directions, and get the safe separation on each direction.

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A traffic tracking software system named TrackerM was developed by our group to detect vehicles and track their movement using video camera recordings. The study focuses on a practical analysis by using reliable data from TrackerM to propose countermeasures for avoiding a collision at a signalized intersection in the center of Niigata, Japan. Three items investigated are: short-cut behavior of subject vehicle (SV) drivers tying to turn right quickly, right-turning timing of SVs to cross the path of oncoming traffic, and countermeasures to avoid a collision between SVs and bicycles. A gap acceptance curve is identified to reveal vehicles of higher probability of causing a collision. The paper concludes with several issues for developing and improving the software system.

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Police enforcement is a common and economical method to reduce red light running, since the automated traffic enforcement instrument such as photo enforcement camera is costly. In this study, we applied the Rasch model to analyze a Traffic Police Enforcement Ability Questionnaire (TPEAQ), and then used it to assess the perceived enforcement ability of red light running. Four main results were obtained: First, the perceived enforcement ability of female polices is slightly higher than male polices'. Second, the prior abilities needed to enhance for female polices are mental and psychosocial demands, whereas the psychosocial and physical demands are the priority for males. Third, heads can deal with the violator's complain well to prevent his objection. Finally, the future training for traffic police should focus on safety driving discipline, strengthen physical loading, and increase the ability of accommodating extreme weathers.

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Worldwide it is estimated that 1.2 million people lose their lives and as many as 50 million injuries and disabilities from road accidents every year. It is more inflicting burden for developing countries like Thailand when Thai statistics indicate over 12,000 people became fatal with accident costs comprising about 3.4 percent of GNP. Among all types of vehicles involved, bus accident is considered a major public concern as transportation of many innocent people is involved. The gravity of the situation is getting more public concern as annually 4,000 bus accidents occurred in Thailand. Single vehicle-bus accident with running off road accounts a major portion of bus accidents. This research attempts to investigate such single vehicle bus accidents to collect detailed information of crash scene, vehicle and occupants. The findings of this research indicate the possible factors leading to collision with a particular demonstration of the case studies.

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Underground urban expressways which have great potential to settle many existing transportation-related problems may pose unknown risks regarding traffic safety. Vehicle accident in tunnel can more seriously damage road infrastructure and human life than outside roads because of its closed space especially in deep underground road. Therefore, it is important to consider the safety countermeasure for preventing not only a single-vehicle accident but also multi-vehicle accidents which are more damaging. We conducted a unique driving experiment with virtual reality (VR) where the multiple subjects can drive simultaneously in the same roadway space. With this experiment, we collected the microscopic driving data of multi-vehicle accidents that originated in a single-vehicle accident. The results of data analysis reveal some important factors causing the occurrence of multi-vehicle accidents.

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In all developing countries over the world, encouraging people are using bus service is considered as a method to decrease traffic accidents and solve traffic congestion to make a better life. However, a negative effect was found while operating bus system in Hanoi due to a certain existing situation. This study mentioned a different approach: the bus system was one reason making more traffic accident in Hanoi. The paper applied the systematic method to find the main causes of bus accident through analysis of existing bus operations. They were found that the current governor policy, bus driver behavior, poor infrastructure and facilities, and management system of the bus companies contributed to more accident and poor traffic so the public transport could not be their own real function. In order to minimize these deficiencies, this paper aimed to propose measures to improve the bus safety and to create higher quality of life for people in Hanoi

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Traffic accident has been one of the hardest troubles and caused to a great deal of strong argument for many years in Vietnam. Regardless of the effort of State and functional offices, traffic accidents have been not only reduced but also increased rapidly. The article analyses causes for traffic accidents and recommendations concrete solutions dealing with the problem. Within early 10 months of 2006, there were 12.000 traffic accidents happening in Vietnam in which 10.422 people died and 9.237 people were injured from those ones, average 30 people dying of traffic accidents daily. There has been a drastic increase in the grievous numbers, which makes scientists concerned and worried. There have been a lot of explanations for the problem; however, road safety has not got the expected outcomes. The below parts will describe the causes of traffic accidents and suggestion of solutions.

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