A road generally has a variety of characteristics and there are several elements which diversly affect the traffic safety and pleasantness and service expenses, etc. in time of operation. Among several elements, the evenness indicating the condition of a road surface not only operates as a determinant controlling a rough or smooth ride but it also gives a considerable effect on safety concerns.
This research is aimed at comprehensively evaluating the condition of a road surface of a highway in consideration of its users. This research conducted an overall evaluation of a road surface condition by adding qualitative data, or a driver's evenness to the existing quantitative elements, whereas the existing research put its focus on a correlation analysis with quantitative factors and qualitative factors through a statistical method.
As for an evaluation method, this research conducted an overall evaluation by using Gray System Theory which makes possible an integrated evaluation.
The analyzed data on the influence of data value observed by comprehensively evaluating a variety of elements could be used as a secondary means of the decision-making process in relation to road maintenance.

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A two-lane road, when a traffic jam arises due to a front-running vehicle, there is a characteristic of having to overtake it by using the lane for the opposite direction. Most of our topography is mountainous and what is worse, the length of overtaking section is limited to 200m ∼400m. Thus, there exist a lot of limits to high-speed vehicles' overtaking. Thus, the installation of a low-speed traffic flow yield-type lane is positively encouraged aiming for the effective management of a two-lane road and reduction in accidents arising from reckless overtaking using an opposite direction. For this purpose, this research selected a yield lane the most suitable for our country's topography & traffic characteristics as an analytical alternative by conducting an examination of the pattern of a low-speed traffic flow yield-type lane, such as yield lane and turnout, etc. In addition, this research elicited the most suitable length & installation interval of a yield lane through PTSF analysis subsequent to the mixing rate of truck traffic and traffic volume.

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In this study, a self-tuning signal control algorithm is developed for isolated intersections. Traffic dynamics at signalized intersections are represented on time-space diagrams using the shockwave theory and information from detectors installed upstream of intersections. Splits are incrementally adjusted so that the delay per cycle is gradually diminished. Cycles are modified to have an efficient use of the provided green times without causing the residual queues. Unlike most algorithms, the proposed method uses occupancy information and can manage traffic even when queues extend beyond detector locations. Simulation experiments on a four-phase intersection with different demand scenarios are performed to demonstrate efficiency of the developed algorithm. Hypothesis tests are conducted to statistically verify the efficiency comparison between the proposed method and the Webster formula. It is found that in case of fixed demand, the proposed method can optimize splits and cycle lengths with no worse performance measures than the optimal fixed-time signal settings. For the variable demand case, the result indicates that the algorithm can adjust splits and cycle lengths in response to the change of demand and provides better performance measures than the Webster formula. The proposed algorithm has demonstrated itself to be a potential split and cycle optimization for an adaptive signal control system.

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This manuscript presents changes in bottleneck capacity at a freeway diverge in Bangkok. This bottleneck was caused by an exit ramp queue moving upstream onto the freeway. Detailed traffic data from an expressway in Bangkok show that traffic states during bottleneck activation could be grouped into three states with different levels of capacity based on vehicle speeds on through-movement lanes and the rates of lane changing maneuvers near the off-ramp queue. Data also indicate that the transitions of traffic states were primarily caused by the changes in exit flows. The lower capacity was initiated by a more restrictive off-ramp flow that causes cut-through vehicles on the adjacent lane impeding through-movement traffic. Once relaxing the exit flow, impeding vehicles could move out of the adjacent through lane and higher capacity often restored. These findings also show how automatic off-ramp control strategies could generate higher bottleneck capacities through detecting traffic speeds on the freeway.

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Vehicular time headway is of fundamental importance in traffic engineering. This research investigated theoretical headway models for a multilane highway in Korea using loop detector data. To analyze time headway by traffic flow states, the collected data were categorized into five flow rates and tested for randomness. Subsequent theoretical modeling was performed at the five flow rates. The Gamma distribution at low to intermediate flow rates, and the Pearson VI distribution at all flow rates were fitted by the Kolmogorov-Smirnov (K-S) statistic. Model parameters were obtained from conventional maximum likelihood estimation (MLE). Analyses were performed on residuals and parameters of the fitted models, as well as various headway statistics. Notably, parameters of the Pearson VI changed markedly during level of service (LOS) C, which presumably reflects the boundary between low and high traffic flows.

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This study presents essential information on motorcycle rider characteristic and behavior resulting from the questionnaire survey for riders and non-riders that was conducted along the top 5 roads in Metro Manila with the most number of recorded motorcycle road crashes in the past 5 years. The questionnaire has eight (8) sections that focus on rider’s personal details, driving experience and training, riding habit, opinion on road safety, road crash experience, motorcycle preference and anger and aggression test. The results of the rider and non-rider survey were analyzed to yield significant variables influencing motorcycle road crash experience and frequency. A total of 2,000 motorcycle rider participated in the survey and a total of 600 other road users.

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Space-mean speed is an important parameter in the capacity analysis of rural and suburban highway. The ability to estimate space-mean speed from time-mean speed or spot speed will assist the study to analyse more data, besides saving time and cost. This paper presents the linear regression models developed for estimating space-mean speed for rural and suburban highways in Malaysia. However, due to the different characteristics and driving behavior between two-lane highways and multilane highways, using only one general equation to estimate space-mean speed for both two-lane and multilane highways is unrealistic and inaccurate. Therefore, it is essential to derive separate relationships for two-lane highways and multilane highways in Malaysia. Hence, in this study, specific models for each road facility which are the two-lane highways and multilane highways were derived. Statistical analyses were also conducted and discussed in this paper. The models derived are statistically accepted.

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This paper proposes a concept of critical post-encroachment time (PET) for all-red clearance interval design at signalized intersections that aims at achieving the optimum performance in both safety and mobility. The critical PET is defined as the minimum accepted PET at the conflict point by the first entering drivers. Variability of the accepted PETs in the case of late exit was analyzed at a study intersection in order to estimate the critical PET. Results showed that they follow a two-parameter Weibull distribution and tend to increase as the entering distance rises. Its 15th percentile value, approximately 2.0s, was then used as the critical PET to discuss the implication in the design of all-red time through numerical calculations. Conclusions supported that the calculated all-red time based on the critical PET could achieve significant operational and safety benefits, as compared with the all-red times based on the existing methods.

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

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In this paper, we construct a structural model of multiple main factors influencing road section traffic flow and safety, which could not be taken into account using conventional DEA. In this model, road sections are compared in terms of traffic flow and safety, and Network DEA is used to assess comprehensively the maintenance priority on the basis of these two parameters. In addition, the priority assessment of road maintenance sections was tested, taking 64 traffic census section locations from Sapporo City's densely inhabited district as a model case. From these results, we found that the maintenance priority becomes clear in cases where multiple factors are considered, and the usefulness of Network DEA is validated through the comparison of analysis results from conventional DEA and the proposed model

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A study of traffic at a signalised intersection under high throughputs should gain better understanding on traffic characteristics and direct to better management strategies for city traffic during peak periods. This study explores an analysis approach by applying restricted stop-line counts under high throughputs from the existing system as inputs based on analytical model to evaluate operation performance of an intersection. Adopting the analytical model in optimisation, the preliminary findings shows the different levels in degrees of saturation leading to distinct interpretations of that between the adaptive system and the analytical model, which might be the results from the detector positions of input volumes, the variations in cycle lengths and the difference of algorithms. Further study in the correlation of the degrees of saturation as the performance measure calculated by the adaptive system and the analytical model via controlling signal timing in the model could provide better comparable values.

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

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In India, signalized intersections experience heavy and non-homogeneous traffic flow. A proper traffic model must consider the varying characteristics of all the road users to effectively design and efficiently manage the signalized intersections. An evaluation reveals the applicability of Highway Capacity Manual's signalized intersection model for an Indian signalized intersection. The evaluation revealed that the model suffers from serious lacunae when applied to the Indian context. Measures are proposed for the modification of the model, and factors are developed based on proposed modifications in order to make it more suitable for Indian conditions. The factors evaluated are the lane width adjustment factor and passenger car equivalency factors. Mean right-turn width used is 3.6 m while the width provided was 3.3m. Equivalency factors for motorized two-wheelers ranged from 0.4 to 1.3 and for motorized three-wheelers from 5.6 to 9.1. In terms of pedestrian safety, LOS of the intersection is not acceptable.

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Because of right-of-way constraints and safety concerns, on-line linear bus stops with no provisions for buses to pass each other can become the only practical means for passenger services in exclusive bus lanes on urban arterials. How to improve the capacities of bus lanes with this type of stops and accommodate demands by bus companies for a greater access to bus lanes is a pressing issue for the transit authority in Taipei, Taiwan. To provide a decision-support tool to address these issues, field data were collected and used to calibrate a simulation model. The model was then used to examine the relationships between capacity and its influencing factors. This paper discusses the findings of the simulation analysis. It also presents an easy-to-use tool that can enhance transportation professionals’ capabilities for capacity and level-of-service analysis.

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Mixed traffic flow is the popular problem now, not only in Vietnam but also in almost developing countries. With the mix traffic flow, we have to consider many problems in traffic control and traffic safety, especially in the cases of some countries that private vehicle ownership increase very quickly. This study was conducted to analyze the change in motorcycle driver behaviors with the progress of urbanization and motorization, the observations is inside intersections between left-turn groups and straight-go groups. From the analysis in this study, the results show the changes of driver behavior in case of one popular city in developing countries - Hanoi. This study also conducted the analysis about the relations between group behaviors and conflict situation inside intersection, from that propose some suggestion in traffic control measures and policies for mixed traffic flow.

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The waiting time at the stop line, one of the factors affecting the gap acceptance behavior, was investigated in this study. The study focused on the u-turn movement of passenger cars at midblock median openings. The statistical analysis was conducted to judge the effect of the waiting time. The analysis results showed that the waiting time of more than 30 seconds would frustrate the drivers to accept the significant smaller gap than the drivers facing smaller waiting time at the 90% confidence interval. The critical gap parameters were also estimated by the classical regression method. The results showed the critical gap of 4.3 seconds and the follow-up time of 3.4 seconds. The capacity models showed the maximum u-turn capacity of 1,060 pcu/hr. The u-turn traffic control and management at median opening was recommended for safety purpose, especially when the u-turning vehicles might face the long waiting time.

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The perception response time of drivers is one of the most important human factors that have significant influence on driving safety. This is the only parameter that unites all car-following models. Some early literatures dealt this parameter as a constant; however more recent investigations have shown that such assumption might not be valid. This paper reports an investigation conducted on the response time of drivers based on vehicle trajectory data collected from test track experiments conducted in Japan using RTK GPS receivers. A new method was proposed to estimate time-variant response time under car-following situations incorporating some important features of car-following behavior such as perception threshold of drivers. The response time data computed using the method was analyzed to investigate inter-personal and intra-personal variations and influence of driving conditions on the response time. The investigation revealed some important features of human driving behavior.

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The basic model of traffic operations at signalized intersections is based on the assumption that when a signal changes to green, the flow across the stop line increases rapidly to saturation flow rate, which remains constant until either the queue is exhausted or the green period ends. In recent years, this assumption has been challenged by some field observations in Taiwan and U.S.A. These observations showed marginal increase in queue discharge rate along the queued vehicles’ position. This paper investigates queue discharge behavior at signalized intersections based on video data collected from one of the busiest at-grade intersections. The methods proposed in the HCM (2000) and Australian Road Research Report 123 to estimate saturation flow rates were assessed against field observations. The results from field observations were similar to those observed in Taiwan and U.S.A., whereas the micro-simulation results went against some common perceptions that believed micro-simulation under represents queue discharge rate.

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In Southeast Asia, motorcycles constitute a substantial portion of road traffic. Thus, a passenger-car-oriented traffic control system cannot operate effectively, and traffic efficiency is decreased. To achieve a sustainable and environmentally friendly society, a traffic control system suitable for mixed traffic including motorcycles is highly necessary. Although some traffic policies targeting motorcycles have been implemented, the criteria for implementing them are still unclear. Indeed, the characteristics of motorcycle-dominant traffic flow are not well understood. Thus, this study attempts to qualify the effect of motorcycle-oriented traffic operations and find the criteria for implementing them on the basis of detailed investigations of mixed traffic flow with motorcycles in various cities with differing traffic conditions. The results show that (1) unclear definition of traffic lanes may severely decrease the efficiency of traffic flow and (2) the most effective traffic scheme varies with traffic conditions.

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This paper shows that traffic propagations can be explicitly expressed by a function of a dynamic travel time model. In density-speed equilibrium models, such as the LWR model and the proposed dynamic travel time models, the vehicular speed is instantly adjusted to the density, regardless of the speed of the subject vehicle. As a result, vehicular accelerations in density-speed equilibrium models do not always fall within a feasible region of the vehicular performance. In order to formulate the actual traffic behaviors regarding vehicular accelerations, this paper proposes a non-equilibrium traffic flow model (i.e., continuum car-following model).

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Continuous flow intersection is one of the unconventional intersections, which are displaced the right turn bay to the opposite side of the oncoming through traffic called "CFI Leg". The signals at the main intersection and the sub intersection are operated by two-phase fixed time signal controllers with a proper signal coordination to provide smooth traffic flow. The distance between the main intersection and the sub intersection is one of the main factors that influences to the capacity of CFI. Using VISSIM micro simulation, distances between main intersection and sub intersection for different traffic conditions were explained. Specifically, it indicated that more entering intersection traffic volume created more traffic delay at the intersection and that needed more distance on the CFI right turn crossing point from the main intersection. In addition, based on the case study at the Khon Kaen City Gate intersection, it clearly showed that both two - legs and four - legs CFI options are a good solution for traffic congestion relief at this intersection. This therefore needs a further study to solve this issue.

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Arterials in metropolitan cities are expected to provide mobility to high volume of traffic. Realistic understanding of traffic flow behaviour for such vital urban roads is essential for traffic operation planning and management for ensuring desired level of service. Metropolitan cities in India carry variety of vehicles with varied static and dynamic characteristics with predominance of two wheelers. The interaction in the midblock section between different types of vehicles significantly varies with the flow rate and therefore has varied effect on the equivalency of vehicle and the service volume. In present study, the traffic characterization on dynamic scale is carried out by considering two wheeler and car as reference vehicles. Speed-flow-density relationships are developed using dynamic vehicle equivalent factors. The results are compared with the static passenger car equivalent values and corresponding capacity for the selected arterial.

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Traffic signals optimise efficiency and safety at intersections by separating conflicting traffic movements in time. To achieve the same vehicle throughput in a reduced signal cycle time, often free left turns are provided for left side driving traffic. The current study intends to evaluate the impact of these free left turns on the traffic behavior by i) measuring their existing capacity utilization and ii) establishing the various factors influencing their performance. Queue lengths and travel times of the left turning vehicles are taken as the indicators of their performance. VISSIM software is used for micro-simulation of traffic and from the results obtained, regression models are developed for queue lengths and travel times. Also, effect of a signalized left turn in place of a free left turn is estimated in terms of the alteration it causes on the queue lengths and travel times of left turning vehicles.

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This study investigates the relationship between accident location and land use patterm in the city of Newcastle upon Tyne, England. This paper distinguishes between males and females of working ages, between weekdays and weekends and between working and leisure time. Data from the the UK Census 2001 showed that most pedestrian journeys to work started and ended in the same ward (an administrative area of approximately 10km²). Accident data were all accidents involving pedestrians of working age during period between 1998 and 2007. Generalised Linear models were developed using the number of pedestrian accidents as response variables and census and land use data as predictors. Sensitivity analysis showed that an increase of 1% in the proportion of retail land use in a ward will, on average, lead to an increase of between 24% and 68% in the number of accidents involving pedestrians of working age.

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Development of a hierarchical tree based regression model (HTBRM) to find the causal factors of traffic crashes at rural sections of the road is presentenced in this paper. CHAID, a type of rarely used type of HTBRM, was used to model traffic crashes in six national roads of Hokkaido, Japan from 1997 to 2001. CHAID is a non-binary HTBRM; therefore, able to represent the complex relationship between traffic crashes and the independent variables. Here four CHAID models; 1 km non-winter, 1 km winter, 3 km non-winter, and 3 km winter were developed. Models with 3 km road segments were found to be better performing. Tunnels, bridges, and snow sheds were found to be significantly increasing the traffic crashes in winter months of the year. Models lustrated a complex relationship between traffic crashes and the independent variables. Further, several combinations of variables with high number of traffic crashes were identified.

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Road intersections are accident-prone locations for traffic. To avoid accidents in the vicinity of intersections, vehicles should avoid entering dilemma zone. In this paper, a model formula was compiled that represents vehicle movement at a signalized intersection to gain an understanding how to ensure safety by making an earlier decision before the signal change to yellow. This formula clearly shows that an earlier decision can result in better safety at signalized intersections by preventing entry to the dilemma zone.

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The current training programs for learning to drive a passenger car in Taiwan are mainly private driving schools. The current evaluation method for the teaching quality of training schools is considered unpractical due to its 51 complicated criteria, and inconsistent with evaluation goal. Therefore, this study aims to review the current evaluation problems and establish a new evaluation system. The goal of the new evaluation system is to ‘improve the educational quality of the course for more knowledgeable and better drivers.’ The objectives are ‘administrative quality,’ ‘course education,’ ‘technical education,’ and ‘research and development’(R&D). There are 9 criteria included in this system. This research applies the AHP (Analytical Hierarchical Process) questionnaire to determine the relative weights of each objective and criteria. And, this study provides a new operational and practical evaluation model for private driving schools according to a detailed design for the measurement of every practical criterion.

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Sun glare is known to adversely affect driving conditions, and some measures against traffic accidents from sun glare have been implemented. Quantitative analysis of the influence of sun glare on traffic accident occurrence has not been carried out, so the seriousness of such glare as a traffic safety problem is unknown. The Chiba Prefectural Police Headquarters has been recording latitude and longitude of the accident location and vehicle travel direction as additional data items for traffic accidents in the prefecture. We used these additional data items to analyze the degree to which sun glare affects traffic accident occurrence. It was found that when the sun is in a position that tends to blind drivers, traffic accidents tend to be more frequent. The effect of sun glare on accident occurrence was quantified and was found to be very adverse.

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The WHO released a Global Status Report On Road Safety: Time For Action in July 2009. Here we analyse the data reported by Asian countries. The report demonstrates that a few high income countries have unreliable statistics, and on the other hand a few low-income countries are able set up good data collection systems. Therefore, all countries should be able to set up reasonable data reporting systems given the right policies. Overall and road user specific fatality rates do not have a high correlation with country income levels. The reasons for this are not known. In the absence of more reliable data and identification of risk factors for each country, it is not possible to give very specific country based countermeasures for road safety. It would be adequate at present to focus on measures that have international validity and are known not to have negative side-effects.

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This paper explores motorcycle/driver characteristics related with motorcyclist accident involvement. An interview targeting motorcycle drivers was conducted in Phnom Penh. A sequential analytical strategy including clustering and classification tree was adopted. After the groups of motrocyclist with homogenous driving behavior are identified by cluster analysis, the classification tree was employed to establish the relationship between accident involvement and motorcycle/driver’s characteristics variables for each of the groups. To identify the importance of the variables associate with accident involvement, Random Forest was employed. The key finding here is that the job has the most significant effect on the accident involvement. Three types of job were identifies as vulnerable groups: Motodop driver, high school student, and university student. Other characteristics associated with motorcycle accidents were also identified and discussed. Based on the discussions, several intervention measures were speculated as potential for motorcyclists’ safety improvement.

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This study was aimed to investigate tactile and audible warning produced by different configuration of transverse rumble strips (TRSs) installed on a two-lane highway. The eighteen different patterns of rumble strips with different thickness, width of each strips, and gap between strips, were examined. The rumble strips were tested with a test vehicle, which was a pickup truck, at different speeds. It was found that as speed of vehicles passing over the TRSs increase, the roadside sound and in-vehicle sound also increase. On the other hand, changes in in-vehicle vibration decrease as vehicle speed increase. Considering the thickness of TRSs, thicker TRSs caused bigger change in in-vehicle sound and in-vehicle vibration. The Department of Rural Roads’ (DOR) configuration TRSs seem to provide adequate in-vehicle sound difference and in-vehicle vibration difference for driver to be clearly notified. In comparison with DOR’s configuration TRSs, the TRSs with 25 cm-gap (W10G25T0.5) seems to be more efficient in terms of speed reduction and making larger change in in-vehicle vibration.

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In Australia, level crossing safety has been a major concern to road and rail authorities. This paper considers the issues related to heavy vehicles safety at level crossings. The aim of the paper is to introduce Petri nets—a graphical and mathematical modelling tool in assessing the scale of risk at level crossings when heavy vehicles passing through intersecting areas. The Petri nets tool, ∏-tool is used to establish the model which is tested using different heavy vehicle percentages on selected level crossing locations in South Australia. The results demonstrated factors such as traffic level of service (LOS), heavy vehicle percentages and the distance of the level crossings to or from the nearest intersection are associated with an increased risk when a heavy vehicle being involved in level crossing collisions. The Petri nets and ∏-tool appear to be suitable for assessing the safety and performance of level crossings.

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We quantified the changes in both utilization characteristics and traffic conflict risk at signalized intersections with improvement of geometry and developed the evaluation model for measuring traffic conflicts between left/right-turn vehicles and pedestrians in order to clarify the relationship among the size of intersection, users’ behaviors and traffic safety. Through the before-after analysis, it was found that the risky behaviors during inter-green period such as rushing into intersection for both drivers and pedestrians have decreased and the traffic conflict risk has also drastically reduced by the compactly-modified intersection. It was also revealed by the developed risk estimation model that the longer time the left/right-turn vehicle requires to pass at intersections, the higher conflict risk occurs. And it was confirmed that the traffic conflict risk may be reduced by the further improvement of intersection geometry through the sensitivity analysis.

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A traffic incident is any non-recurring event that causes a temporary reduction in the roadway capacity due to a variety of effects, such as traffic accidents, disabled vehicles, road construction, etc. Among them, traffic accidents are one of the most important events since they might lead to casualty as well as traffic congestions. Predicted accident durations are vital to the mitigation of traffic congestions caused by traffic accidents because such information alerts drivers of the necessity to re-route or re-schedule their trips. Therefore, accident duration prediction constitutes one of the most important steps in the accident management process. This study aims to investigate influential factors on large-vehicle accidents and to analyze the impacts of the factors on accident duration distributions. The results show that the accident duration distributions are significantly different among each other and thus applying different duration distributions together will contribute to more accurate prediction of accident durations.

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Recently, the concern over ISA has been growing in European countries. Introducing ISA into residential roads in Japan may significantly improve the traffic safety of bicycles and pedestrians. However, ISA also represses the convenience of drivers. The aim of this study is to develop a method for evaluating the burdens of drivers due to Mandatory ISA. Firstly, the factors affecting the speed selection of drivers on residential roads is analyzed based on a driving experiment. Secondly, based on the total cost minimization concept, a speed selection model which considers the trade-off between perceived accident cost and delay cost is developed. Then, the total cost which drivers perceive when driving at a certain speed under a certain road environment condition is estimated. The result shows that the perceived total cost will increase by 0.5% ∼ 6.5% and 19% ∼ 39% with the ISA limiting to 30 km/h and 20 km/h, respectively.

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Delineators are useful devices for ensuring safer driving maneuvers. Effective placement and operation of a delineator are essential to its impact on safe driver maneuvering and result in the prevention of traffic accidents. This study proposes a methodology for determining the parameters associated with optimum delineator placement and operation, which include the spacing, height and size of the delineator, from the perspective of user satisfaction. A binary logistic regression technique is adopted to incorporate user satisfaction into the methodology. The proposed model is capable of producing a probabilistic measure of user satisfaction with respect to various parameters. For example, based on the proposed methodology, the optimum delineator spacing should be 6.10-14.28 m to obtain 70% user satisfaction with a diameter of 100 mm. The outcomes of this study can serve as useful fundamentals for more effective placement and operation of delineators.

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In this paper, two models are proposed for automatic incident detection on urban roads in Hong Kong. The first model is the threshold-based incident detection model, adopting the ratio of predicted speed over estimated speed as the detection criterion. The second model is established on a basis of the discriminant analysis. These two models are evaluated, in terms of detection rate, false alarm rate and mean time to detect, under different pre-incident traffic conditions (represented as level of service), using the traffic data from a real-time travel information system in Hong Kong. Also, the impacts of level of service on the model detection performance are specified and quantified in this study. The empirical results indicate that the pre-incident traffic conditions (congested or non-congested) may significantly affect the detection performance of models.

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This study aimed at finding appropriate interval of ranged speed hump from the viewpoint of noise and vibration as well as effect of speed reduction through two experimental installation. In the experiment, "sinusoidal mobile humps" were used. In the first experiment, conducted in Kokubunji city, it was found that 60m-inerval can reduce speed less than 30km/h in all over the road section. However, residents complained the noise caused by re-acceleration. In the second experiment conducted in Bunkyo-ward, Tokyo, the intervals between humps reduced to 20m to make drivers to "give up" to re-accelerate. Judging from the result of questionnaire survey and noise observation, it was successful.

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This study proposes a GA-based approach to find the optimal strategy that minimize the overall traffic network costs in case of road closure due to heavy snowfall. A mesoscopic simulation model is adopted to evaluate the system performance in the course of GA implementation. The proposed model is applied to both a simple test network and a real-world freeway network to analyze its performance and practicability. Analysis results suggest that the proposed approach consistently yields near-optimal solutions. They also indicate that the GA-based solution performs much better that the current practice used for determining the snow removal sequence.

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

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Many new technologies using ITS have been developed in order to reduce traffic accidents. Adaptive Cruise Control system (ACC) is one of such ITS. The impacts of ACC installation on traffic accident within traffic flow has not been evaluated because of difficulty evaluating accident occurrence with respect to complexity of interaction between vehicles with and without ACC. Thus, the approach was developed to estimate traffic accident occurrence after installation of ACC by using a micro traffic simulation model which was basically modified by adding a function of perception-response process. In this approach, traffic accident occurrence was access by detecting conflict on the simulation. In addition, the evaluation method was developed by using proposed safety indicator. To evaluate the influence market penetration of ACC, many cases with different installation rate of ACC were simulated by using the proposed approach and relationship between installation rate and safety indicator was analyzed.

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Bus rollover crashes have claimed many lives and injured even more victims. The rare occurrence of the crash as compared to other crash configurations such as full frontal and side impact has underrepresented the fatality caused in rollover crash. In Malaysia, there have been several fatal high profile cases involving bus rollover. Adopted in 2007, ECE R66 is in force in Malaysia to prevent disastrous consequences as a result of a bus rollover crash. The paper describes the methodology of performing a rollover simulation to a bus, albeit only to selected body section. Commercially available software was used to develop a finite element model based on the manufacturer’s 2D drawing. With close reference to the ECE R66 regulation, simulation was conducted and results were presented in the form of structural deformation overview and energy vs. time history.

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A sustainable transport system needs to focus not only on reliability and efficiency, but also on the safety aspect. Speeding problem has becoming one of the major road safety focuses around the globe (Global Road Safety Partnership, 2008; OECD/ECMT Transport Research Centre, 2006). Many researchers have shown the negative effect of speeding on road safety (Nilsson, 2004; Walz et al., 1983; OECD/ECMT Transport Research Centre, 2006). One of the speed management strategies to reduce the harmful effects of speeding is by utilizing in-vehicle technology such as intelligent speed adaptation (ISA). Several previous researches have shown the effectiveness of ISA system in reducing the speeding problem (Sundberg, 2001; Lahrmann et al., 2001; Jamson et al., 2006). This concept paper discusses the settings of a pilot study in Malaysia along with its challenges as well as recent progress on adapting a commercially available handheld GPS device as working ISA system.

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Motorcyclists are the highest contributors to road fatality statistics in Malaysia, particularly young riders. This warrants a study to be carried out to understand the overall accident characteristics and investigate the associated risk factors. Secondary data from police records (POL 27) were utilized using three years of accident records (2006 - 2008). Results shown that the following factors led to a higher probability of being killed or severely injured (KSI) for young motorcycle riders; being a male motorcyclist, riding with a learner probationary license or without a license, riding with an improper helmet or without wearing any, being involved in a crash that happens during the wee hours, being involved in a crash that happens during dawn or dusk or in the dark with and without street lighting, being involved in a crash that happens at built-up or rural areas and being involved in a head-on collision.

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The traffic accident database is the sole important source outside of traffic police that could help effectively to understand the traffic safety situation. For right usage, this study has clarified its special feature such as better liability, difference of purpose, object and standard. The data of 2009 confirms the efforts to ensure the traffic safety so that the fatalities are under control, but the seriousness of traffic accident is very high. Especially, the study has proposed a methodology to find out the Correction Factor of the number of accident sufferer. Based on the corrected value, it could reconfirm that the number of injured published by traffic police is unrealistically low. It shows the underreporting level is about 63 times. It proved that the corrected data are quite in concordance with a rule from the Vietnamese Injury Pyramid that for each fatality, there are 58 injuries at difference seriousness.

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This study deals with an aircraft acquisition decision model to tackle the stochastic demand of the air transportation system. Probabilistic dynamic programming is applied to develop an optimization model with the aim to maximize the operational profit of the airline company. Correspondingly, a probable phenomenon is defined to comprehend the uncertain state variables so that the targeted level of service by the airline company could be met satisfactorily. The proposed probabilistic dynamic programming model is then converted into a non-linear programming model as the objective function and the constraints have non-linear expression with respect to the decision variables. Later, the proposed model and the solution method are examined with an illustrative case study to determine the number and the types of new aircraft that should be purchased at every time period. The results show that the proposed methodology is viable in providing the optimal solution.

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This study presents an exploratory analysis of the consumer surplus of passengers flying across the Taiwan Strait. The travel cost method was used on the data collected from Taipei-to-Shanghai travelers. Based on the analysis, the truncated negative binomial model was selected to derive the air travel demand function, and the consumer surplus was calculated as the reciprocal of the coefficient of the air travel cost variable. The results show the consumer surplus is about 58,000 NT$ per trip, per passenger for the sample, and the CS of passengers using direct flights is approximately 1.5 times of the corresponding value of passengers using indirect flights. This paper proposes a feasible methodology to analyze the economic benefits of the air transportation market, particularly for the specific case examined in this work. This investigation also presents some interesting directions for future studies.

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Most of the studies on container terminal planning are conducted from a bottom-up approach; the operational data in terminal operations have been collected and used as bases to estimate possible strategies for deploying terminal facilities to handle increasing container traffic. The drawback to a bottom-up approach, however, is that the output can only apply to specific terminals under certain conditions. To compensate for the shortcomings of this technique, we adopt the top-down approach to break down terminal planning rules by long-term observation of the development of mega terminal operators. Two Hong Kong based mega-terminal operators, Hongkong International Terminals (HIT) and Modern Terminal Ltd. (MTL), were selected as the samples. The objective of this study is to determine the terminal planning rules followed by mega-operators and consequently provide practical references for terminal operators. Together with analysis generated from the bottom-up approach, terminal operators will be able to thoroughly examine terminal planning rules and make the best choice for the deployment of terminal facilities.

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The archipelagic nature of the Philippines gives rise to relatively unique transportation system requirements. As a result, travel demand models from other countries may not be entirely applicable to an inter-island scenario. The objective of this paper is to identify the determinants of mode choice for inter-island travellers in the Philippines, using data describing travel between Manila and Busuanga Island, where the main choices for travellers that were considered were air travel and sea travel. Using data from a stated preference experiment conducted on ship travellers, this paper applies binary choice logit models to evaluate the impact of fare differences, trip characteristics and the socio-economic attributes of respondents on their mode choice.

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This paper provides the future projection of CO₂ emission from international aviation, considering changes of international network structure and fleet size. The network structure includes two common types, namely the hub-and-spoke system and the point-to-point system, and two other in-between network cases are assumed. Also regarded is the more use of smaller aircraft for more efficient and more frequent flight services. The two cases for fleet size include the use of current size fleet and smaller size fleet. The future aviation demand and CO₂ emission is projected under six scenarios, built by the combination of these cases. The result suggests that the utilization of smaller aircraft induces less amount of CO₂ emission. Also, the point-to-point system has the effect of CO₂ emission reduction to some extent.

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