This paper presents the properties of Malaysian paving grade conventional binders 80/100 and 60/70 subjected to multiple stress creep and recovery test (MSCR) at 58, 64 and 70 °C. The dynamic shear rheometer was used to carry out this test. Measurements were made on unaged, quarry short-term aged, and Rolling Thin Film Oven Test aged samples at two stress levels, 100 and 3200 Pa. The delayed viscoelastic response was evaluated with recoverable strain and the resistance to permanent deformation with non-recoverable compliance. The results and variations at different stress levels are substantially different among both binders at different stages of ageing. In general, the percentage recoveries are higher for short-term aged compared to unaged binders. The process of ageing was found to decrease its Jnr values at all MSCR test temperatures and stress levels which indicate that short-term aged asphalt binders are less susceptible to rutting than unaged binders.
A study using permeability as the main parameter was performed to examine the drainage and clogging behaviors of different pervious concrete mixes used for pavement construction. This paper presents the findings of the clogging performance of the pervious concrete mixes against possible clogging materials found in Singapore roads. Clogging was created by introducing clogging materials progressively into the pervious concrete tested. A constant-head test was used to determine the permeability of the pervious concrete at different stages of the clogging test, and the clogging performance was determined by monitoring the reductions in permeability as clogging developed. The clogging potentials of different pervious concrete mixtures are represented and compared in terms of the deterioration trends of their respective permeability as the clogging process progresses.
Hydroplaning is a major cause of accidents in wet-weather driving on highways. The presence of surface runoff or ponding on pavement surface can cause a fast moving vehicle to hydroplane if the vehicle speed equals or exceeds the hydroplaning speed. Rutted highway pavements present increased safety risks because the ruts along their wheel paths collect water during wet weather, thereby reducing the hydroplaning speed due to the higher water depths along the rutted wheel paths. This paper proposes an analytical framework to evaluate the hydroplaning potential of rutted highway pavements using a finite-element computer simulation model. An analysis is presented to show that the presence of ruts has a significant effect on the vehicle hydroplaning speed of a rutted pavement over the range of rut depths commonly encountered on expressways and major arterials where traffic speeds are high and hydroplaning is an important safety concern.
Because of the material variability during the construction process, the material properties can not be determined accurately. In order to include this variability, the probabilistic approach has been proposed in the pavement analysis to consider the realistic situation in the construction process. In this study, the stochastic finite element is developed to investigate the effect of design parameters variability to pavement structural and performance analysis, and the mean and variance of pavement distress are computed. The statistical parameters of material properties are backcalculated from FWD test data, and the LTPP database developed by FHWA in the United State were used to evaluate the statistical parameters of pavement. Then, the average and the variance of the response parameters such as displacements and stresses are computed, and the statistical parameters of rut depth and fatigue cracking under traffic loading are also calculated, and the results can be used for pavement reliability design.
The toll stations are removed after a new toll system starts to operate. This research aims to examine the performance of mentioned system in Taiwan. By selecting proper locations at certain days before and after system begins to work, traffic situations are compared. Flow rates increase a little but the difference is not great, while average speeds are quite stable in January until March and later, when the tendency of increase is found. Moreover, when data from questionnaires are collected, it is observed that five of seven items of monetary measures belong to be one-dimensional, and the others indifferent. Almost the same, Five of eight items of timely measures belong to be one-dimensional, and the others indifferent. Thereafter, IP analysis and district classification are used to decide which measures take higher priority for improvement, then, it is also found that satisfaction increase importance of these measures significantly by logistic regression.
We propose a method for road maintenance patrol planning using multiple vehicles, which is modeled as an integer-linear problem. Specifically, we consider a model for reducing the number of patrol vehicles and optimizing the patrol routes. Difficulties arise in solving such routing problems because of sub-tour elimination with multiple vehicles. To address this sub-tour problem, we use the Space-Time Extended Network (STEN). We investigate a virtual network using the proposed method, and describe the behavior of the proposed model. The time required for the calculations is short, so that the system is suitable for practical applications.
The temperature in the asphalt pavement layer varies which is influenced by climatic environment factors, such as air temperature, humidity, solar radiation, wind speed and the reflection of the pavement surface. Indonesia has a specific tropical climate characteristics and a temperature observation station was placed on the national road segment of Singaraja - Amlapura (Km 81 + 100 - Km 95 + 00) which is located in Karangasem regency in the eastern of Bali Region, Indonesia, to monitor air temperature, humidity and temperature of asphalt pavements at depths of 00 mm, 20 mm and 70 mm. It is obtained that, there was a positive linear relationship between the air temperature and asphalt pavement temperature. Based on the statistical analysis and test models, it can be concluded that both variables have a high correlation, and most of the asphalt pavement temperature variation can be explained by those two independent variables.
Flash floods occur mostly due to obvious reasons such as clogged drains, huge surface run-off, the drainage capacity of the existing drainage system could easily be exceeded and lead to excess surface water could not be drained out that quickly. This project is proposed to design and assess the effectiveness of a porous pavement structure for the purpose of maximizing water infiltration. A total of eight square concrete slabs with different hole pattern with the dimension of 0.3m x 0.3m and the height of 0.5m were designated. The results indicated that holes in concrete influence the permeability of water pass through the designed concretes and thus affect the flow rate of the water. In addition, aggregate height plays a role in influencing the flow rate of water. The higher pavement height provides lower flow rates. Moreover, the bigger the size of aggregate contributed to the higher the flow rates.
Lack of natural stone and expensive cost of purchasing high-quality aggregate promote the utilization of steel slag. The asphalt mixtures incorporating basic oxygen furnace steel slag (BOF) as coarse aggregate were prepared and subsequently subjected to various laboratory tests to determine the engineering properties of asphalt concrete. Results show that BOF provides higher stability value compared to natural-aggregate-based asphalt mixtures. Steel slag would include angular and rough textured particles that could enhance the interlocking mechanism. Test sections were constructed by using three different types of asphalt mixtures as follows: stone mastic asphalt with BOF, dense-graded asphalt concrete with BOF, and dense-graded asphalt concrete with natural aggregate. Pavement performance including rutting, ride quality and friction was collected and analyzed. Field data indicated that the use of BOF steel slag as aggregate present a viable solution for asphalt pavements, which could ensure a satisfactory level of performance.
This paper presents how bonding condition between asphalt pavement layer can be predicted by comparing pavement moduli from measured deflection by FWD test and computed deflection from structural analysis through backcalculation process. The structural analysis which involved varies bonding condition was carried out by BISAR software using Shear Spring Compliance and the other hand the backcalculation process was carried out by ELMOD5 software using four layer pavement model with varies bonding condition. The results indicate that the shear modulus prediction can be conclude from minimum differences between both of kind of pavement moduli. Beside that the measured deflection for pavement which have good bonding are located between computed deflection which have partial bonding condition. Better bonding condition at the interface between layers will cause the decreasing of pavement deflection, as the results the better structural capacity can be achieved with better bonding between layers.
Parking of vehicles along on-street or off-street areas has become a problem for the downtown center of Cagayan de Oro. Divisoria currently has vehicle parking and traffic issues. This study aims to determine and evaluate baseline parking supply and demand of Divisoria. The parking survey includes a block-by-block inventory of parking spaces in the area between 8:00AM to 5:00PM during weekdays. The results of the study revealed that the amount of parking supply will not meet the daily parking demand in the area. The parking conditions are inadequate on both Mondays and Wednesdays. Furthermore, the parking frequency and the rate of parking utilization revealed that driver's difficulty in finding a parking space progresses from morning to afternoon as the demand for parking spaces also increases. Finally, the study presents recommendations for on-street management, off-street parking facility, improvements on public transportation and vehicular regulations to improve parking conditions.
The researchers introduced different quantities of strontium aluminate to traffic paint to achieve phosphorescence. Factors to consider for this study are charging time, lux received, luminance emitted, amount of SrAl2O4:Eu added and its effects through abrasion. It was found out that the luminance emitted vs time follows a power f(x)=axn where x is in minutes. There are positive trends when relating lux emitted with charging time with percent strontium aluminate added with millimeters of paint removed.
This paper presents the results of a study of AC-BC asphalt mixture with reclaimed asphalt pavement (RAP) and produced by warm mix method. 30% of RAP was combined with new aggregate in mixture. Rejuvenating agent Cyclogen L was used to activate RAP asphalt binder. With 3% Sasobit, temperature of mixing and paving was set at 135°C and 123°C, 30°C lower than conventional mixture with unmodified asphalt binder 60/70 penetration. Three mixture was set in this research, i.e. hot mix asphalt conventional mixture (namely control mix), warm mix asphalt mixture ( SASO) and warm mix asphalt with RAP (SASO RAP). OBC for each mixture was 5,2%, 5,2% and 5,3% for control, SASO and SASO RAP respectively. Regarding the result of resilient modulus and fatigue resistance test, the SASO and SASO RAP showed a better performance than conventional asphalt mixture.
This research evaluates the operational performance of Signalized Intersections involving U-turns (SIU) in Aswan city, Egypt. Furthermore, it investigates the impacts of U-turns on the capacity of an SIU, exploring the key factors influencing the performance of an SIU. To achieve those objectives, the research methodology depends on onsite video observations and field measurements. In addition, to examine the efficiency of the proposed strategies, the microscopic simulation software PTV-VISSIM has been used. The research findings revealed the adverse effects of U-turns on the performance of an SIU. This study recommends the segregation of the U-turns from the signalized intersections. It also emphasizes the urgent necessity of the overall readjustment of traffic controls signal times based on a traffic demand analysis.
Time headway and speed distribution studies provide an insight into the aggregate flow of vehicles which have important applications in capacity estimation, Level of Service (LOS) analysis, safety analysis, etc. Analysis of time headways and speed of vehicles were conducted on the basis of data collected from four two-lane bidirectional roads in Assam, India by video recording technique. The paper intends to study time headway distribution of vehicles for the mixed vehicular flow and for different leader-follower vehicle pairs on the basis of six traffic flow levels [0-200, 200-400, 400-600, 600-800, 800-1000 and 1000-1200] PCU/h. Analysis of collected speed data is also carried out to obtain the speed distribution patterns in mixed traffic condition and also vehicle class-wise speed analysis is performed to identify the impact of overall flow and vehicle composition on speed. The results of this paper can find direct applications in developing micro-simulation models.
Traffic calming means engineering and several other techniques introduced on roads to reduce speed and number of motor vehicle. Traffic calming project prioritization is a system or process developed to rank streets for phasing projects. Four factors/attributes are identified in this research regarding traffic safety concerns namely vehicle speed, vehicular volume/width of street (per unit time), side walk condition and pedestrian generations. A questionnaire survey was conducted to four residential areas near to the top four priority streets based on their severity in terms of traffic safety concerns. Binary Logistic Regression analysis was employed to reveal the residents level of conformity with the prioritization process. The objective of this research is to explore residents' compliance with the prioritization process. Resident's approval with the street's priority increases the probability to agree with the priority ranking system. Result provides important variables of group of residents who agreed with the prioritization system.
The car-following platoon consisted of ten vehicles with the leading vehicle initiating perturbations on a test-track. Vehicle movements varied based on the speed patterns initiated by the leading vehicle with each data set including a cycle of stop, acceleration, car-following, deceleration, and complete stop. Shock waves are normally used for stop and go conditions at a fixed location, however this study focused on observing repeated shock waves created by the same group of drivers repeatedly. As well as studying the vehicle trajectories in microscopic level, speed wave propagations among the vehicles were also studied considering asymptotic stability in the car-following platoon. After carefully reviewing the stop and go vehicle trajectories, it was found that there is a discrepancy between actual vehicle trajectories and hypothetical uniform traffic flows in the shock wave theory derived from the macroscopic traffic model especially in the case of short distances.
A four-layer artificial neural network (ANN) structure was set up in the models and a genetic algorithm (GA) and back-propagation methodology were utilized to customize individual driver's behavior. A number of combinations of the input variables was examined with the R2 values representing the model fitting. This paper concluded that there are significant differences in degrees of contribution to the models among the several input variables. The most important finding was that the leading vehicle's (LV) acceleration had stronger relationship to the following vehicle's (FV) acceleration rate rather than the relative speed between the leading vehicle and the following vehicle. Additionally, the input variables related to the preceding vehicle of the leading vehicle (PLV) were added in the model. It was also found the variables of the preceding vehicle of the leading vehicle help car-following models slightly, but they were not as much as expected.
In India, most of the capacity augmentation activities have been carried through expansion of the existing bi-directional carriageways into four lane divided carriageways, which has brought the practice to provide the median opening at every 2 km and the same has been brought in the form of an ordinance by the concerned authorities as well. U-turn median openings considered among the most hazardous locations on highways. It is essential to understand the gap phenomena occurring at the median openings. This paper reviewed gap acceptance phenomena occurring at U-turn median openings studied by various researchers in India and abroad. In this study, gap acceptance behaviour on the candidate test sections was evaluated by employing different gap acceptance modeling methods. Based on the results, it was observed that the critical gap of 4.5 seconds is optimum for designing the median opening on inter-urban corridors in India.
The advanced surveying technologies have been available to use monitoring of road condition and vehicle running situation. The mobile mapping system can collect 3D spatial road data to estimate road alignment such as sight distance from driver. And more, the precise GPS can detect vehicle trajectory with high accuracy to clarify running position. These new technologies could provide detailed relationship with speed reduction at curve section. Therefore, the objective of this study is to verify influence factor on speed reduction at curve section by using the advanced surveying technologies and evaluation of drivability by questionnaire. It was concluded that the sight distance at short-divided section is critical factor for speed reduction.
The goal of Advance Traveler Information System (ATIS) is to improve traffic flow and safety by providing up-to-date information of traffic network. In this paper, traffic information (travel time) estimation based on fused traffic state data is presented. A centralized architecture is used to fuse the traffic sate data from different sensors based fusion by averaging and fusion by median and to estimate the travel time based on the simultaneous travel time estimation model accordingly. Two case studies are selected to investigate the performance of fusion models based on freeway data in USA and the arterial road data in South Korea. The results show that the fusion by median performs best. The model is able to eliminate outliers in the data with less effort of complex mathematical process. It can be used as a benchmark for comparison with other advanced fusion models.
This paper proposes a traffic state prediction method based on two perspectives; short-term and long-term prediction. Modified KNN method is used for short-term prediction from recent 2 years of historical data set. Pattern of the day of the week is used to predict long-term. To overcome the gap between the result of short-term and long-term prediction, the weighted average for two predicted results is considered as the final predicted result. The proposed method is tested in the real urban expressway network and the performance of the proposed method is evaluated in this paper.
Today, traffic congestion is one of the most challenging and complicated problem in Cagayan de Oro City thus, this study aims to evaluate the congestion issue in Cogon Market, particularly, the traffic performance along the unsignalized intersections that include the roads of Yacapin, Capt. Vicente Roa, Osmeña and J.R. Borja streets. The methodology involves data collection of three variables: vehicle traffic flow (i.e Level of Service), pedestrian (i.e. walkability), and parking (i.e. parking demand & supply). Preliminary results revealed that traffic congestion were primarily due to: absence of traffic signals (i.e., vehicle and pedestrian), poor condition of pavement markings (i.e. parking and crosswalk), inadequate parking facilities, obstruction of vendors along the sidewalk, inadequate pedestrian facilities, and poor traffic enforcement. Moreover, Level of Service (LOS) of roads along these intersections ranges between LOS E (i.e., unstable flow) and LOS F (i.e., forced/breakdown flow). Thus, a traffic management scheme is highly recommended.
As a speed-reduction measure on a motorway, Central Nippon Expressway Co., Ltd. has been conducting field research of light-emitting devices placed at regular intervals on the shoulder of a road, and controlling the light emission in arbitrary light-emission patterns to control vehicle running speeds. In this paper, operational experiments conducted on the Tomei Expressway to alleviate the traffic congestion caused by sags and tunnel bottlenecks are introduced, and the effects of the installed system on the flow rate and vehicle movement for both the no-congestion and the congested situations are discussed. An analysis is carried out using vehicle detector data and video tape recorder (VTR) image analysis. The results show that the speed of vehicles is affected by the devices, and a significant increase in throughput is observed for the congested situation, whereas there is only a small effect on the flow rate for the no-congestion situation.
To simultaneously consider simulation accuracy and efficiency and to acknowledge the prevailing mixed traffics of cars and motorcycles on urban streets, this study proposes a mixed traffic macro-micro model which is able to convert upstream macroscopic traffic flow into downstream microscopic flow with consideration of lateral drifts and transverse crossings of motorcycles by determining the jam density and free flow speed according to car-motorcycle density ratio and lane-changing behaviors on multilane roadways. The proposed model is validated by a field case. The validation results show that the performance and applicability of the proposed model is promising. Additionally, the error rates of simulated motorcycle flows at different lanes are higher than those of simulated car flows. The error rates of traffic flows on inner lanes are lower than those on outer lanes because of the prohibition of motorcycles in traveling on the inner lane.
While motorcycle is the most favorable vehicle kind in Vietnam, their necessary data are very poor. All gathered facts consist of accumulative registered amount (Mreg) and some associated ones. But important information such as data on motorcycles in current traffic circulation (Mcir) is quite absent. Such usage of registration records instead of real data is background for high incorrectness in related policies/countermeasures. To cover this gap, the paper presents an estimation of different kinds of essential data for motorcycles in traffic circulation until 2014 and also presents a fresh forecast on amount of motorcycles until 2025. With found data, impacts of socio-economic conditions on the growth of motorcycles are considered and it shows that in contrary to strong impact in long-term, the impact in short-term is very weak that means the existence of additional influence factors. This conclusion has great practical meaning for policy-making in different terms.
With the rapid growing popularity of cellular phones, cellular vehicle probe (CVP)-based travel time information systems become comparatively advantageous. Due to the vague positioning problem of CVP, to directly determine the travel path with the closest travel time may lead to an erroneous result. This paper proposes a virtual trip line matching model to determine the travel path of a call user by using the Yen's K-shortest paths algorithm to obtain potential paths and the multinomial logit (MNL) model to develop the map-matching model. A simplified network is used to estimate the MNL models and to validate the performance of the proposed model under various traffic conditions simulated by Paramics traffic simulator. The results show that the proposed model remarkably outperforms than the traditional model which simply chooses the path with the closest travel time to time lag of paired cellular geolocation points.
In Southeast Asian countries, fixed-point sensors for road traffic are under development, while the information and communication infrastructures have rapidly improved. Thus, smartphones with various sensors, such as GPSs and accelerometers, are commonly used. As a result, it is possible that traffic conditions could be monitored in real time using smartphone data rather than fixed-point traffic detectors. We have developed a method to classify transportation modes (i.e., passenger vehicles or motorcycles) using data collected from smartphones. The experimental results indicate that the standard deviation and spectrum of synthetic acceleration are measures that can accurately classify transportation modes.
This research aims to study driver behaviour of public transit bus at Batu Feringghi road in Penang island of Malaysia. The study investigates the relation of driver behaviour; speed and acceleration, with road geometry and passenger perception. The data were collected from 27 bus journeys with 22 different bus drivers in the period of June to July 2014. The findings include 1) the Batu Feringghi road design is inconsistent in terms of operational speed and posted speed limit, 2) the combination of horizontal and vertical alignments can influence the driver behaviour, 3) the tendency to speed is twice linearly significant for road-familiar drivers compared to driving-experience drivers, 4) the driver characteristics (age and experience) are negatively significant to the lateral and longitudinal accelerations, and 5) the occupant comfort is a function of acceleration but not the speed, and the standard deviation parameters as the most suitable identifiers for this function.
Traffic accidents shortly before and after sunset in Chiba were analyzed. The rate of traffic accidents shortly after sunset was found to be higher than at any other time, whereas the rate shortly before sunset was found to be lower. Traffic accidents caused by sun glare tended not to occur shortly before sunset, because the presence of topographic features meant that the sun had already effectively set. The rate of pedestrian accidents shortly after sunset was higher than that of any other time; the rate shortly before sunset was slightly lower than in day and shortly after sunset, because it was not dark and drivers were not dazzled by sun glare before sunset. However, it is already the case that many vehicle headlights are on shortly after sunset, so it is difficult to decrease pedestrian accidents only by advising drivers to use their lights in the hour before sunset.
This study investigates cause and effect relationships among risk perception, positive affect and risky behaviours of motorcyclists in Denpasar, Bali using Structural Equation Modelling. Questionnaires were distributed to collect age, gender, self-reported risky riding behaviour, perceived risk and positive affect of motorcyclists. This study found that positive affect influences more than risk perception on risky riding behaviours. Accordingly, this shows that motorcyclists on the road are relied more on intuitive than rational processes. Motorcyclists have also been found to consistently perceive and behave on such a risky behaviour that may distract them on the road, for instance using a mobile phone while riding. In addition, riding fast on curves is a behaviour factor which strongly indicates both rational and intuitive processes of motorcyclists' decision making while on the road. Further studies should be more focused on the influence of positive affect of motorcyclists' ages and gender on risky riding behaviours.
A flyover over an existing at-grade intersection is constructed to reduce traffic congestion. However, under the flyover which has been shown to help relieve traffic congestion at the intersection, the traffic signal control still uses the same control method as the “before” situation; that is the fixed time control plan. After the installation of the flyover, it was found that about 45% of traffic diverted to it, the time delay reduced by 34% over the same period. The economic evaluation results show that the net present value equals 361.64 million baht, benefit cost ratio, 1.34 and internal rate of return, 37.58 percent. The paper describes economic benefits of the flyover and presents the performance of the flyover improved intersection and points out the remaining problems under the flyover. Suggestions for improving performance of the existing traffic signal are made using results from SIDRA software.
Collision with roadside objects such as trees, utilities and guardrail are a major road-safety problem and reported the highest rate of side-impact accidents on roadways in which about 225,000 people have been involved. In this study the common methods to evaluate occupant risk factors involving in crash to roadside barrier systems are reviewed. The collected previous real crash test on guardrail system with regards to occupant impact risk factors are prepared based on different system performance. Higher average for longitudinal impact velocity for Thrie-beam system is found. On the other hand, Weak-post system is provided less severe system in terms of longitudinal impact velocity.
Drinking alcohol reduces driver's ability to do safely and increases risks of crashes. Behavioral models were applied and developed to understand the driver's decision for drinking and driving (DAD) behavior. Theory of Planned Behavior model, Health Belief model and Integrated Behavior model were included then Integrated Behavior model was proved to be the best model for predicting both intentions and behavior of DAD. The most significant factors of the driver's decision models were subjective norm, affective attitude and behavioral intention. These findings could help the local authority to propose factors for proper intervention programs and policies in order to minimize efficiently the DAD behavior of drivers.
According to Grime (1987), among several factors, the human error factor contributed 95 percent to traffic accidents, and denoted the sole factor that led approximately 65 percent to the accidents. Meanwhile, the World Health Organization's (WHO) Global Status Report in 2013 revealed that among the road users' categories, motorcyclists noted the highest number of 36 percent that were most likely to cause a death during the traffic accident, especially in Indonesia. This paper therefore aimed to analyze the extent to which human behavior, as the major factor, has affected the traffic accident by considering the accident history that occurred over the last five years in Bandung based on gender and age categories. The motorcyclist driving behavior was examined based on DBQ's (Driver Behavior Questionnaire) theory, which represents three factors, namely, lapses, errors and violations. In addition, the study also conducted a statistical analysis through SEM's (Structural Equation Modeling) method in order to investigate the extent to which the cause of accident has been correlated with the riders' behavior on the road. The result of the study then showed that there are differences between male and female motorcyclists' accident in Bandung, whereby the male riders' accident due to lapses gained 0.232 of the positive correlation, while most of female riders who got accident due to violation noted 0.227 of the positive correlation.
The u-turn traffic at midblock median opening has to wait for the acceptable headway of conflicting through traffic stream. This research proposed the waiting time estimation by spreadsheet simulation. The spreadsheet software generated random headway size according to the known statistic distribution. The randomly generated headways were compared with the critical headway, which is assumed to follow the log-normal distribution, to determine whether the u-turn vehicle accepts the headway. The data was collected at a midblock median opening in order to evaluate the estimation result. The results showed that the proposed method can estimate the waiting time well when the through traffic volume is not large. When the through traffic volume is large, the collected waiting time is much lower than its estimated value. The result implied that the u-turn drivers became impatient while waiting for a long time and conducted the unsafe forcing u-turn maneuver.
Intelligent speed adaptation (ISA) has the possibility to be a drastic tool for traffic calming in Japan if they are disseminated once. The aim of this study is to examine the drivers' acceptability for the three types of ISA associated with the types of target roads and some monetary incentive measures. To achieve the aim, a field experiment with Advisory ISA and a SP questionnaire survey were conducted. Based on the field experiment, the effectiveness of the combination of Zone30 regulation and Advisory ISA is presented. Next, by the SP survey and a model analysis, it is revealed that the types of ISA, the types of target roads on which ISA work, and the amount of monetary incentive measures affect the acceptability of relevant ISA. It is finally suggested that a Voluntary ISA working only on community streets has the potential to be disseminated for traffic calming.
This study aims to determine the crossing characteristics that contribute to accidents and propose mitigating procedures. Each railway/highway grade crossing was evaluated based on their existing characteristics namely: type of crossing, type of barrier, warning device, and the volume of traffic using the highway. Using hazard indices, each characteristic was evaluated individually. Two-way crossing has higher hazard index compared to one-way crossing, half barriers also exhibited higher hazard compared to full barriers. In the case of warning device, crossings with two different sets of warning device on each direction have exhibited the highest hazard index and 30-40 thousand for the vehicle traffic volume. Using chi-squared test, two combinations of characteristics passed the test, namely: the daily traffic volume versus barrier type and alarm device type versus crossing type. An assessment of all the characteristics for specific crossings was also made to evaluate the hazard index of a specific level crossing.
In the past, traffic engineering designs are mostly based on car traffic volume, delay, and travel time and efficiency oriented. However, the traffic composition and traffic volume of motorcycle are very high in Taiwan and in some Asia countries as well. The traffic engineering design must take motorcycles into consideration. Besides, proportion of motorcycle in the accident casualty is also very high, and furthermore, the number of motorcycle causality is increasing in recent year. In the past, the segregated flow concept to substitute for mixed traffic has been implemented and has caused the decrease of the death accident. However, the injured accidents is still increasing continuously. Therefore, the study aims at analyzing the accident data using collision diagram and an accident diagnosis process to find out the traffic engineering design problem and to propose the new design method for reducing motorcycle involved accidents.
It is a common practice for left turning vehicles (left hand traffic system) to share the same traffic signal phase with pedestrian at signalized intersection. Although signalized crosswalk are operated to give pedestrians prioritized right of way, accident data reveal that left turning vehicles are not always being able to give pedestrians their right of way. As such, it is important to find the reasons for why the left turning vehicle driver fails to grant a legally-crossing the pedestrian right of way. To investigate the effect of intersection angle on the yielding behavior of the left turning vehicle driver with pedestrians, this study used data from an observational study, conducted at nine signalized intersections in Japan in 2013. In this study events related with sudden brake and acceleration for avoiding collision is considered as “non-yielding” behavior. The results show that driver's behavior at obtuse angled intersections is more "non-yielding" than other typed intersections.
Humps were legally accepted in Japan as a part of road structure by a revision of the Road Construction Ordinance in April, 2001. Although there were various studies on effects of humps on speed reduction, effects of accident reduction were not found in the literature of hump studies. In addition, it should be noted that previous studies mostly focused on 1 year-afterinstallation-effect. A longer effect of hump was not observed. Therefore, the objective of this study is to investigate accident reduction effect and long-term effectiveness of permanent sinusoidal humps. Further efforts were made to grasp local residents' acceptability of permanent sinusoidal humps. According to the findings of this study, accident rate was reduced approximately 2.3 accidents per year by setting sinusoidal humps. In addition, the local residents' acceptability was increased when there is a playing ground for children located near the sinusoidal hump setting place.
This paper attempts to provide an additional insight into the factors that significantly influence the motorcycle accident severity in Thailand by using ordered probit, binary orbit and binary logit model. We used the data from two sources: Department of Highways (HAIMS) and Road Accident Victims Protection Co. Ltd (Eclaim), each of which depicts different factors involved in the accident. This study reveals several factors that could lead to severe motorcycle accidents and casualties: during late night and late morning, during weekend and holiday season, collision with truck, driving under influence, crash at curve, motorcycle to vehicle collision esp. head-on types, age above 40 years old, pillion passengers and asphalt pavement. Our findings reveal that the chances of being fatal in motorcycle accidents are higher in motorcycle-truck collision than motorcycle-other vehicles collision. Also, the likelihood of fatality of pillion passenger is higher than rider.
Accident counts at a site are usually assumed to be Poisson distributed. However, past studies have shown that many variations exist in the accident data, which often results in the data to be either overdispersed or underdispersed. Thus, a Generalized Poisson (GP) distribution is introduced as an alternative distribution for accident counts data. The GP distribution can cater the data that are more or less dispersed than required by Poisson distribution. This paper examines the appropriateness of using GP distribution in accident data analysis and Empirical Bayes (EB) safety estimation method. The results show that the GP distribution is a better fitting model than Poisson distribution such that, generally, the goodness-of-fit statistics studied (SSE and χ2) are significantly improved. When the GP distribution is used to modify the EB method, it is able to improve the prediction of safety as compared to the original EB method.
Fatal high-speed head-on collisions often occur in the limited spaces of two-lane roads without median strips. Wire rope guardrail systems can be seen as an alternative to median strips. Such systems use thin posts, have a buffering function and require minimal width. The purpose of this study was to develop a wire rope guardrail system with a buffering function as a separator for two-lane roads. CG simulation and collision experiments using real vehicles were conducted to determine the necessary characteristics of the fence, and performance tests were conducted in accordance with guard fence installation criteria. As a result, a wire rope guardrail system that satisfies Japan's Am Performance Standard Criteria for expressway median strips was developed. A driving test was conducted to study the feasibility of introduction to two-lane expressways.
This study carried out driving experiments on safety check behaviors and vehicle movements at five roundabouts in Japan. Specifically, each driver's attention when entering or exiting the intersection was analyzed by using video and drive recorder data. As a result, it is revealed that the safety check position is positively correlated with the safety check speed for the case of entering roundabout, however this relationship is not clearly confirmed for the case of exiting roundabout, especially 4-leg roundabout cases. From the analyses of necessary deceleration rate (NDR) for safety stop before the crosswalk, it is found that colored pavement triggers high deceleration at roundabout entries. On the other hand, as for roundabout exits, it is revealed that 4-leg intersection has a high impact on the deceleration value, whereas both left turn movement and the existence of pedestrian at far side edge of crosswalk reduce the NDR value.
In improving road safety, identifying black spots based on safety potential is also known as identifying locations with potential saving in accident costs. Such identification is an attempt to make the selection of black spots which are most suitable to treat out of the identified ones. This paper intends to introduce an approach to identifying locations with potential saving in accident costs. In such approach, the key parameter used to assess the safety performance of road spots is the safety potential. This approach enables the identification of the black spots for which safety improvement measures are expected to have the greatest economical effectiveness. As a result, the approach is of great use to accident reduction in developing countries facing limited budgets for road safety improvement.
This paper developed an Analytic Hierarchy Process (AHP)-based framework to quantify influential key aspects, namely operation, economy, and environment that greatly affect airline fleet planning decision-making. The developed framework is embedded with a traveler mode choice modeling process in order to capture supply-demand interaction explicitly under uncertainty. It is beneficial to the airline management to allocate flexibly appropriate weight (priority) on the respective key aspect for fleet planning purposes. By investigating Malaysia Airlines and AirAsia as a realistic case study, the findings reveal that the developed framework is useful to: (1) capture and quantify influential key aspects mathematically in making strategic fleet planning, (2) assure adequate fleet supply of airline to meet stochastic demand, (3) model supply-demand interaction in greater details, (4) maximize the operational profit of the airline at a desired service level, (5) provide a greater flexibility to the airline to acquire/lease aircraft throughout the long-term planning horizon.
This research investigate four possible operational risk encountered in a sea port, namely, human factor, facility and equipment factor, natural environment factor, and management factor. The AHP questionnaire survey and Importance- Performance Analysis (IPA) technique are employed to find out eight of the thirty nine sub factors have high degree of importance with low performance scores. These eight sub factors include the extent of vehicles drivers obedience to regulations in the port area, degree of port stevedoring labors’ obedience to port safety guideline, port stevedoring labors’ correct attitude toward port risk management strategy, the stevedoring labors’ emotional stability, miscellaneous equipment and facilities maintenance condition, port staffs’ security control ability, port staffs’ working schedule arrangement, and the length of stevedoring labors’ working hours per day. Four of the eight sub-factors are human factors. Thus we conclude the human factor required immediate attention to improve the successfulness of port risk management strategy.
This study examines the geographic factors and logistics connectivity performance of airport cargo transshipments to enhance cargo competitiveness at Taiwan Taoyuan International (TPE) airport. Flight rights of airport cargo routes, route flight distances, flights scheduled per week, number of flight destinations, and carrier and logistics turnaround times were selected as the study parameters. A total of 111 cargo routes at TPE airport were studied using a DEA model and regression estimations. The results showed that the average operational performance of short haul routes was better than the average operational performance of long haul routes. The average cargo operational performance of the TPE transfer cargo was found to be better than the average cargo operational performance of non-TPE transfer cargo. Route length, city-pair destinations, flight frequency, aircraft payload, and apron capacity were found to be very influential factors in the performance of transshipment development for cargo routes at TPE airport.
River-based cities are now capitalizing on the potential of their bodies of water to serve as critical transportation networks to complement land-based transport. For these cities, their water tributaries have historically served as commuter rivers to accommodate indigenous, inland water transport modes (IWTs). Despite its potential to support local economic development, scholarly literature on IWTs has remained fragmented and scant. This paper redresses this gap by exploring IWTs in four developing country-cases in Southeast Asia, to gain a better understanding of their role, function and use within the overall transport system. Using a case study approach, this paper starts by formulating an indigenous IWT framework. This framework is then used to assess IWTs. Results have shown that the levels of indigeneity of IWTs may provide important insights to inform the development of IWTs as a crucial component in developing an integrated, sustainable transport system in cities in developing Southeast Asia.
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