Moisture damage can manifest in the hot mix asphalt pavements in forms of stripping and/or softening of asphalt. It results in loss of stability and bearing capacity failure, and rutting of asphalt pavement. One of the common anti-stripping additives, hydrated lime, is considered to improve the properties of asphalt mixture in resisting moisture damage. The lime application process can be introduced to asphalt mixture by either adding dry hydrated lime to wet aggregates or adding lime slurry to dry aggregates. This study aims to evaluate the laboratory performance-based properties of asphalt mixtures using two different lime application processes as well as to compare between hydrated lime-modified and polymer-modified asphalt mixture. Results indicated that the performance of hydrated lime modified asphalt mixture in moisture damage and rutting resistance is related to the lime application processes. Adding hydrated lime to asphalt binder is an effective and economical method to improve performance of asphalt mixture in moisture damage and rutting resistance.

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Most backcalculation programs are based on the linear-elasticity assumption. Laboratory results have shown that pavement materials possess a nonlinear stress-strain relationship. The purpose of this study is to develop a nonlinear backcalculation program which will be used to analyze the test pavement sections in the Long-Term Pavement Performance (LTPP) database in the United States. The selection criterion for the test pavement sections is that there are strong nonlinear behavior for the drop weight and peak deflection relationship for the test pavement section. The Falling Weight Deflectometer (FWD) test results from these test sections will be compared with the predicted results from linear and nonlinear backcalculation analysis. The backcalculated material properties will also be used to predict the deflections of the FWD test data for different drop weights. Finally, the backcalculation results will be used for the structural analysis, and the results from the linear and nonlinear analysis are different.

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In existing literature on road alignment optimization, only some cost factors related to the road itself are considered. But actually a new road is not only an isolated transportation facility, but also obviously a component part of a road network. In this paper network impact analysis is incorporated into the road alignment optimization model. Each road alternative can change the topology structure of the original network. As for each alternative, flow characteristics of OD traffic on the links are obtained through traffic assignment, and thus changed travel time and environmental load of OD traffic on the network can be estimated. They are converted into monetary equivalents and are regarded as the benefit incurred by the alternative. The ratio of benefit to cost is used as the objective function to evaluate each alternative. Genetic Algorithm is employed to solve this model.

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The purpose of this study was to assess some operational and safety issues related to rural crossing mechanisms: a “traditional” diamond interchange design with roundabout intersections at the ramp termini, and a less conventional design incorporating local roads, called an extended diamond interchange. Various levels of traffic demand were considered through computer simulation. The primary safety metrics were the speed differences between an approaching link and a circulating link (SDAC), and the speed differences between consecutive time windows (SDCW) on an approaching link. In both light and heavy traffic conditions, the extended diamond interchange with roundabouts including local roads seems to be safer, by these metrics, than the typical design because the longer ramp to roundabouts makes traffic flow more stable. For the operational performance, total delay time was surveyed. In heavy traffic conditions, the extended design is stronger than the typical design thanks to more space for vehicle queues.

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Implementing mechanistic-empirical (M-E) pavement design approaches in practice, the need that the pavement performance level related to the limit state function such as fatigue cracking or rutting can be controlled considering inherent variabilities associated with design input parameters and systematic bias of the design procedure is being more considerably presented. This paper presents the practical applications of principal reliability concepts to the M-E pavement design and a reliability-based design approach for the M-E flexible pavement design using overall and partial safety factors to design a pavement cross-section satisfying performance threshold with a target reliability during its intended design life. This paper shows that the pavement sections designed with a reliability level using AASHTO 93 design guide don’t have uniform structural reliability in terms of the mechanistic distress of fatigue cracking and the uniform reliability can be achieved by the a reliability-based design approach using overall and partial safety factors.

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The deicing work is usually considered as a main part of the highway maintenance activity in during the winter season. The deicing includes the physical method which removes snow with tools and the chemical method which removes the snow with deicing material. When removing snow using deicing material, excessive deicing material will cause the environmental and budget problems. If the deicing materials are used less than the required amount, the snow will remain on the road surface. For these reasons, the adequate usage of deicing materials is important. In this research, the performance of deicing material has been evaluated and the amount of deicing material has been determined according to the amount of snow through the laboratory and the field experiments. Also the adequate usage of deicing material has been determined by 130kg/km-lane on two lane road.

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Portable falling weight deflectometer has been used to evaluate stiffness of subgrade and/or subbase. The stiffness is estimated using a pair of peak values of load and displacement. However, test data are dependent on specification of measurement apparatus. Instead of peak values of load and displacement, this study have used historical time data of load and displacement to estimate layer stiffness. The estimated stiffness was comparable to the one obtained from plate bearing tests. The objectives of the study are to improve accuracy on estimated stiffness and to decrease influence of individual apparatus specification.

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Based on the analysis of several asphalt mixtures in Indonesia, generally, asphalt mixture has stiffness modulus (E₁) varies from 2000 MPa to 5000 MPa. At the subgrade layer, soil has CBR value at 3% to 6% which is equivalent to modulus (E₃) at 30 MPa to 60 MPa. The second layer would be a base layer with thickness considered to be a constant value at 200 mm and stiffness modulus (E₂) at 100 MPa. The other characteristic is Poisson’s Ratio (ν). Poisson’s Ratio for surface (ν₁), base (ν₂) and subgrade (ν₃) was taken as 0.35; 0.40; and 0.45 respectively. Considering the material characteristic above then design nomograph were developed. The nomographs were inspired by Nothingham and there are then 4 types of nomographs related to a subgrade modulus. Pavement thickness result designed using mechanistic procedure was thicker than empirical method.

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Semi-flexible pavement is a composite pavement that utilizes the porous pavement structure of the flexible bituminous pavement which is subsequently grouted with an appropriate cementitious material. The main purpose of this research is to investigate the influence of superplasticizer type and dosage on the flowability of cementitious grouts. The grout mixtures were designed to attain high compressive strength while maintaining flowable properties to ensure that the cement slurries infiltrate easily through the ungrouted samples and to fill up the voids under the influence of gravitational action. In order to attain the workability required, three types of superplasticizer were used. Two were of polycarboxylic ether polymer and the other was of sulphonated naphthalene formaldehyde origin. Results showed that type and dosage of superplasticizer influence the workability of the cementitous grouts.

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Pavement rutting is a major problem on heavily travelled flexible pavement specifically on climbing lanes. Reinforcement of Bituminous mix might be one of the possible remedies that can be considered to improve the performance of a pavement in terms of rutting resistance. It is thought that the addition of glass fibers to asphalt mixtures enhances material strength and fatigue resistance while adding ductility. Because of their excellent mechanical properties, glass fibers combined with SMA mix might offer an excellent potential for asphalt modification. This paper investigates some fundamental properties and rutting characteristics of glass fiber reinforced Stone Mastic Asphalt. The laboratory tests undertaken to evaluate the effect of the fiber content on the bituminous mixes comprise the indirect tensile test, creep test and resistance to rutting. Overall the inclusion glass fiber resulted in higher resilient modulus, higher resistance to permanent strain and higher resistance to rutting. Mix with 0.3% fiber content showed the highest performance. Good correlation was obtained between the laboratory tests parameters (stiffness and permanent strain) and rutting performance of reinforced mixes. The dynamic creep test was found to be more reliable test in evaluating the rutting performance of asphalt mixtures as compared to the IDT test, in addition the contribution of aggregates internal friction to the rut resistance was found to be more significant than mix cohesion.

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To protect pedestrians, bicyclists, and the quality of living environment, vertical and horizontal speed reduction devices (SRD) are often utilized to reduce the vehicle speed. SRDs not only contribute to reducing vehicle speed, but also redistribute the traffic flow due to the change of travel time which implies the residents have also to endure the inconvenience of SRD. To help evaluate the SRD installation, this study uses the traffic flow-speed-density relationship setting the minimum travel time as the objective function to establish a steady state traffic assignment model. Different traffic settings and SRD installation schemes are tested and evaluated which shows that the introduction of SRD is most significant when traffic outside the traffic calming zone is at high volume peak period. By proper choice of SRD type and installation scheme, through traffic outside the community cutting into the local streets can be significantly reduced.

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This paper presents nonparametric generalized additive models to detect both lane-blocking and shoulder incidents for two freeways in Colorado and California, USA. The parametric generalized additive models were developed based on the examination of the partial prediction of the variables of the nonparametric generalized additive model. This paper also highlights the importance of developing incident detection models to detect both lane-blocking and shoulder incidents. The performance of the nonparametric generalized additive models were also compared to multilayer feedforward neural network based models. The model proposed outperformed the neural network based model.

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Mixed road traffic with a high proportion of motorcycles is a typical vehicle composition in Hochiminh City, Vietnam. Due to the nature of such a traffic stream, the method commonly used in evaluating the efficiency of traffic signals cannot be adopted here. Motorcycles are performing differently to traffic signals compared with passenger cars; in particular, their advanced mobility and flexibility resulted in a failure of the application of traditional traffic signal evaluation tools. This paper attempts to report a new approach for the issue; using a modified Passenger Car Equivalent unit (PCE) to convert motorcycles into standard car unit. Then aaSIDRA is applied to conduct a standard evaluation process on the performance of traffic signal designs; a range of output from aaSIDRA can be used to compare the differences with different signal settings. Finally, using the developed PCE factor, queuing and delay measured from aaSIDRA can be converted back into motorcycle delays.

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Prediction of travel times is a vital part of many advanced traveler information systems. Linear model is used in this research as it is effective, computationally efficient and reliable to the available freeway detector data. In this paper an explicit analysis of the linear model is shown and a method to predict freeway travel times using a linear model is proposed. The proposed method is applied to a data set of Hanshin Expressway, Japan.

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Over time transport networks are expected to remain highly reliable to ensure that users can experience smooth travel under both normal and abnormal traffic conditions. To design a reliable transport network properly it is necessary to take into account users reactions to incidents which cause disruption in different parts of the network over time. In order to design a reliable network to deal with such time-varying events it is necessary to capture the user’s route choice behavior under degraded conditions with the time dimension explicitly considered. Furthermore, for practical reasons, it is imperative that any improvement scheme be possible to implement. Therefore in this paper we formulate a time-dependent reliable discrete network design problem where the user’s behavior in route choice is modeled through the game theoretic approach. The ability of this model to design the critical links over time is demonstrated through two numerical studies under different budgets.

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This paper proposes a novel filtering approach to scrutinize the characteristics of traffic flow dynamics measured in various time intervals during different times of day at different spatial locations. The proposed approach executes stepwise procedures to filter out periodic/quasi-periodic time series by Fourier power spectrum, equilibrium fixed points by the largest Lyapunov exponent, randomness by iterated function system (IFS) clumpiness maps, and followed by distinguishing chaoticity and stochasticity by correlation dimension. The dataset used in the numerical study is collected from the detector stations of Taiwan Freeway No. 1. The numerical study mainly analyzes the properties of dynamic traffic flows of four detection stations, sampled, respectively, in 20-second, one-minute, three-minute and nine-minute intervals, measured during midnight, morning, afternoon and evening periods. The results indicate that different nonlinear patterns, including fixed points, randomness, and chaotic-like phenomena may exist irregularly, contingent on the measured time intervals and observed times of day.

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By applying the concept of information entropy in the information theory, this study aims to create a complexity index to measure the driver-perceived driving environment and to give remedy for the past indexes’ incapability of showing drivers’ perceived comfort and safety. The complexity index is calculated by the drivers’ driving behaviors of speed, acceleration and deceleration, and horizontal shift area. We show that the complexity index is a proper qualitative index to truly reflect the drivers’ perception of driving environment and to measure the level of service. It can be a supplement index for the traditional traffic measures.

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Increased economic activities and improvements in quality of life have resulted in a corresponding increase in human and material traffic across existing transport networks. Hence, there is a need for examining the reliability of these networks. The main objective of this study is to examine travel time reliability of various sections in the Han-Shin expressway network Osaka and Kobe area. Performed travel time reliability evaluation of each route considered in this study. To do this, various existing travel time reliability indices are considered and are examined. The advantage of travel time reliability is that, it can be used in policy assessment as a new evaluation technique and also may be used as travel time related information to the system users. Further in this study, conventional congestion measures presently using a measuring performance of Han-shin expressway network are compared with travel time reliability measures. Results reveal that reliability measures are more capable of measuring the variability in congestion level.

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It is expected to control traffic light safely, especially at inter-green periods because the drivers’ judgments whether pass or not at that time affect the occurrence of severe traffic conflicts. 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 road travel time research. This research adopts SCATS data and micro-simulation techniques to overcome the problems of data shortage. In terms of traffic data, SCATS provides detailed traffic signal setting data and volume data meanwhile micro-simulation produces various detailed traffic outputs for the need of developing the travel time prediction model. The result demonstrates that the developed mathematical travel time prediction model has the ability to provide reliable travel time results on arterial roads. The following research will focus on the extension of the model to deal with the prediction of travel time under over-saturation condition.

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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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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 spaces, 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, time-mean-speed and percent occupancy time 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. It is also found that the predictive accuracies can be affected by the means of representing traffic series in terms of various time intervals, time lags, dimensions of state spaces, 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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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. A case study is introduced to estimate the parameters of proposed models using microscopic traffic data collected at some intersections in Vietnam. The finding here can be applied to develop a motorcycle simulation model, which is very necessary for Asian countries.

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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 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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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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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 timeseries 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 highway 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.

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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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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. This study shows very promising practical applicability of the proposed models in the Intelligent Transportation Systems context.

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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, 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 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 traffic tracking software system, 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 reveals that short-cut behaviors are liable to cause a collision particularly when a time gap is less than 4 seconds. 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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This study aims to value the subjective cost of slight and serious motorcycle accidents using the stated preference method by using a willingness to pay (WTP) approach. Willingness to pay is one way to assess the cost and impact of road traffic casualties. The main objective of this study is to investigate the relationship between age, income and number of children of the respondent and their willingness to pay for reducing slight injury as a result of motorcyclist accident. Two binary discrete choice models have been modeled to quantify of the subjective cost. All the independent variables on both models have the expected signs and are significant at 5% level. The goodness of fit of the model to the data is found as a moderate figure.

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This research study estimates the risk factor involved in alcohol impaired driving and the disregard of helmet legislation from hospital data of 28 public hospitals in Thailand (from year 1999 to 2003) and thereby calculates the economic loss in motorcycle accidents influenced by alcohol consumption. It also unveils the alleged association between the marketing and advertising strategies of the alcohol and motorcycle manufacturers and motorcycle accidents. The outcome of the study estimates the economic loss due to motorcycle accidents involving alcohol to be US$ 1,444 million per year. The study also reveals from a questionnaire survey that the campaigns against drunk and un-helmeted motorcycle riding is failing against lucrative thrill seeking marketing strategies adopted by the alcohol and motorcycle industries to attract the young generation.

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An in-depth crash analysis is a systematic approach to identify the contributing factors and to discover the causes of a crash. The important starting point for this concept is to map-out the series of events which result in a crash. This is an alternative approach which leads to efficiently remedy and prevent future crashes. This paper adopts the in-depth crash analysis concept to indentify the contributing causes of a fatal crash in a case study of Srisab Gate, one of the main entrances of the Prince of Songkla University, Hat Yai, Thailand. Crash information including at scene and related information were collected. Data analysis, evaluation of potential causes, and recommendation of countermeasures of the case study are presented. The research team wishes to spark up the concerned authorities’ interest in the indepth crash analysis and hopes to promote this concept as an effective tool to tackle the road crash problem in Thailand.

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The aim of this study is to construct the traffic accidents authentication models for the Local Traffic Accident Authentication Committees (LTAAC) as reference. In present, due to the committee members will change every two or four years and different LTAACs will authenticate the similar case with different results. This study will build a database which includes 5,268 client data, and the collision types include car/car, car/motorcycle, and motorcycle/motorcycle. This study utilizes the artificial neural network method (ANN), and the classification tree method (CT) to construct the models. This study shows that both of authentication models all have over 70 percent accuracy in the accident responsibilities.

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Road traffic accident (RTA) is one of the major social and public health problems in Malaysia. In year 2006 alone, the total road traffic crashes in Malaysia were 341,252 cases whereby 35,425 people sustained injuries due to road traffic accidents. This figure is 0.15% of the total population (26.4 million) in Malaysia. In order to analyze the road traffic injuries, a Malaysian Road Traffic Injury Surveillance System was developed. The system is a database program written in Visual Basic 6.0 (VB6) with MySQL 4.0.21-nt as the database management system (DBMS). It is useful to store RTI data, printing hospitalization report, perform simple cross tabulations and data analysis. The system contributes in adopting the Abbreviated Injury Scale 1990 update 1998 injury codes for describing motor-vehicle injuries.

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