Loading...

Archive

    For Selected: Toggle Thumbnails
    Forum about Comprehensive Transportation System
    Clustering Taxi Quantity Regulatory Levels of  Chinese Capital Cities
    YAO Zhi-Gang, CHENG Gao
    2012, 12(5): 1-6. 
    Abstract ( )   PDF (466KB) ( )  

    Different purposes of taxi quantity control lead to different performances of quantity regulation in Chinese urban areas. To obtain a clear division of taxi quantity regulation levels of Chinese capital cities, a fuzzy cmeans clustering is presented. The paper identifies six important demanding factors such as population, urban builtup area, transit volume, GDP, road area and amount of intercity passenger to get the corresponding indexes of urban taxi quantity regulatory levels. An effecient classification scheme is selected with clustering effectiveness analysis and Fstatistics test after running a dedicated the MATLAB 7.0 program. The result indicates that thirtyone capital cities of mainland China are definitely classified into five categories. The categorization of quantity regulatory levels in this paper provide references for formulating the of taxi license supply models.

    References | Related Articles | Metrics
    DeprivationBased Transportation Equity Evaluation Model for Rapid Urbanization Areas
    JI Xiao-Feng, ZHANG Yu-Peng, CHEN Fang
    2012, 12(5): 7-13. 
    Abstract ( )   PDF (502KB) ( )  

    To improve the transportation equity of urbanization areas, manifestation and causes of transportation equity of urbanization areas are analyzed based on the urban transportation equity theory. In view of the differences between urbanization areas and metropolitan areas, this paper evaluates the traffic fairness from the perspective of accessibility based on the deprivation theory. Measurement methods of traffic trip tolerance degree threshold, expectation threshold, spatial accessibility, etc. are put forward, and a quantitative model is proposed to measure the influence based on the absolute deprivation theory and relative deprivation theory. Calculation result shows that the absolute deprivation degree and relative deprivation degree of urbanization areas residents have been effectively evaluated by transportation equity evaluation model based on the deprivation theory. The paper indicates that lack of transportation infrastructure is normal in urbanization areas, and improvement measures of transportation equity should pay more attention to traffic policy adjustment, public transportation system improvement and psychological guidance for urbanization areas residents.

    References | Related Articles | Metrics
    Overloading Truck Users’ Behavior Analysis under the Policy of Toll by Weight
    WANG Jian, HU Xiao-Wei, LI Cui-Xia
    2012, 12(5): 14-19. 
    Abstract ( )   PDF (637KB) ( )  

    To reduce the freeway trucks’ overloading rate and ensure the freeway’s normal operation and transportation order, the policy of toll by weight has been applied in China for years. Based on the domestic and international study results on freeway toll by weight, this paper takes the rates of toll by weight decrease in Heilongjiang Province of China on November 15, 2011 as the case study. With the traffic operation data of Wapenyao toll plaza, this paper calculates the price elasticity of overloading truck before and after the toll rates decrease, adopts a combination of theoretical derivation and data analysis to discuss overloading truck users’ behavior under the policy of toll by weight. It then puts forward some recommendations on the implementation of toll by weight, which provides the reference for the healthy development of freeway toll by weight.

    References | Related Articles | Metrics
    A CrossEntropy Method for Solving Selection of Multimodal Transportation Scheme
    JIANG Yang, ZHANG Xing-Chen, WANG Yong-Liang
    2012, 12(5): 20-25. 
    Abstract ( )   PDF (428KB) ( )  

    To investigate the multimodal transportation scheme optimization problems, this paper transfers the problem into a combination optimization problem, and a crossentropy method is employed to solve the problem. In an attempt to find the best transportation scheme under the background of integrated transportation with the minimized cost, a targeted crossentropy method is proposed and the specific calculation steps are also listed. In the process of calculation, to verifies the efficiency of the crossentropy method nodes split network is employed to describe the multimodal transportation, ,and the problem is transformed to be a shortest path problem. The result shows that transportation and transfer cost plays a significant role in the problem, and the proposed crossentropy method can realize the optimization of transportation scheme.

    References | Related Articles | Metrics
    Classification of Urban Emergency Based on Traffic Guarantee
    HE Ya-Qin, LI Jie
    2012, 12(5): 26-30. 
    Abstract ( )   PDF (425KB) ( )  

    Emergency classification serves as the basis of the reasonable allocation of supplies and rescuers. It is also the important premise of making preplan and the key technology of emergency management. The emergency classifications in previous studies are always conducted after the accident without considering the traffic guarantee during the accident. This reduces the accuracy of classification and plays minor role in emergency management. Moreover, most of these studies are qualitative. In this paper, a quantitative model of emergency classification during the accident is proposed. Considering the traffic guarantee of emergency rescue, the influencing factors of emergency classification are presented from three aspects: characteristics of emergency, impact on society and capable of traffic guarantee. The local weight of factors and subfactors are determined using the fuzzy analytic hierarchical process. Then the proposed method is applied in a real fire.

    References | Related Articles | Metrics
    Intelligent Transportation System and Information Technology
    A Car-following Model Based on Discrete Choice Theory
    ZHENG Jian, SUZUKI Koji, FUJITA Motohiro
    2012, 12(5): 31-38. 
    Abstract ( )   PDF (1783KB) ( )  

    In the car-following model proposed in this paper, the acceleration and deceleration are incorporated into seven alternatives, and alternativespecific parameters are adopted to capture different attractiveness of each alternative. To avoid interferences from lanechanging behavior, the model is estimated and validated by trajectory data in the high occupancy vehicle (HOV) lane. From the estimation results, most estimated parameters are significantly different from zero at 95% confidence level, which indicates that the chosen variables and the classification of alternatives are effective and reasonable. In addition, according to the proposed model, the changing tendencies of choosing different alternatives at different speeds and gaps are completely consistent with common driving behaviors. The validation results show that, for the chosen alternatives, the percentages of predicted probabilities that are larger than 1/7 (the average probability of choosing each alternative) are more than 87% in the used data sets. From the shares of observations point of view, there are only minor differences between the observed and predicted results. Finally, this model is applied to simulate the 30minute single lane traffic conditions. Through simulation results, it can be found that the proposed model can accurately represent the real traffic conditions on the macroscopic level, while, on the microscopic level, there are some defects needed to be further improved.

    References | Related Articles | Metrics
    Setting Scheduled Trip Time Based on AVL Data
    XU Jia, SHEN Yin-Dong
    2012, 12(5): 39-45. 
    Abstract ( )   PDF (871KB) ( )  

    The trip time (ST), as an essential parameter, greatly affects the compilation and on-time probability of a vehicle schedule in public transit services. Unfortunately, the significance of ST has not been generally recognized in China. The values of STs are usually set manually based on experiences, which are normally hard to reflect the realworld situation. To set proper trip times, a novel automatic approach based on the AVL data is proposed. The basic process is as follows. First, running time samples are abstracted from a large set of AVL data, based on which the homogeneous running time (HRT) bands are then decided. Meanwhile, the knowledge base of running time distribution is established. Then, the ST parameters corresponding to each HRT band are generated based on a waiting time model. Finally, a simulation system is developed to test the schedules compiled based on a given set of STs, which may be revised further according to the simulation results. Experiments on the bus line 4 of Haikou of China show that setting the STs by the proposed approach brings high ontime probability to vehicle schedules.

    References | Related Articles | Metrics
    One-dimensional Traffic Cellular Automaton Model Considering Driver Fatigue
    QU Shi-Ru, JIA Guang-Shuai
    2012, 12(5): 46-51. 
    Abstract ( )   PDF (1870KB) ( )  

    Aiming at the accurate representation of road traffic flow with operational state influenced by driver fatigue, this paper proposes an improved onedimensional cellular automata traffic flow model, and further discusses the traffic flow under the model. WIt first analyzes the properties of the pilot fatigue under the periodic boundary conditions. It then defines the vehicle fatigue ratio which describes the degree of fatigue in a certain traffic flow. Two evolution rules, by fatigue vehicles and normal vehicles respectively, are used in the model to update vehicle operation states. Simulations reveal the underlying relationships between each pair of the speed, the flow density and the flow quantity under various fatigue ratios. Further analysis on safety of traffic flow including fatigue vehicles is also proposed in this paper. The simulation results show that along with the fatigue ration increasing, (a) the places traffic congestions happened trend to scatter in space, (b) congestion frequency increase significantly, and (c) the flow safety declines. Experimental results prove the superior of the proposed model in an accurate representation of the traffic flow over the SDNaSch model.

    References | Related Articles | Metrics
    Simulation of Automotive ABS Using Fuzzy Self-tunning PID Control
    WANG Hui, YANG Lin
    2012, 12(5): 51-56. 
    Abstract ( )   PDF (723KB) ( )  

    The antilock braking system (ABS) is a nonlinear system with the working environment changing. However, either classical or modern control theory are based on the linear system, and there is no matural theory on nonlinear system at present. Once the conventional PID control at the object changes, the parameters of the controller cannot be automatically adapted. With the fuzzy control, PID control, thd fuzzy inference method is used to achieve the PID parameters online selftuning and a fuzzy adaptive PID controller is designed. On the basis of car model analysis and the PID control and fuzzy adaptive PID control, ABS brakes movements are simulated by the Simulink software. The proposed method significantly improvs the application performances of the fuzzy control and the PID control. The results showes that the fuzzy adaptive PID control method can obtain better braking effects, and the system dynamic performance and safety performance are also improved.

    References | Related Articles | Metrics
    FPGA Implementation of Traffic Image Compression
    LIU Tong, SHI Zhong-Ke
    2012, 12(5): 57-64. 
    Abstract ( )   PDF (1296KB) ( )  

    To solve the problem of storing or uploading large amount of image data in traffic image processing system under nonnormal traffic conditions, this paper designs a traffic image compression system based on FPGA. With the features of traffic image compression, the parallelization of JPEG algorithm, which has relatively low complexity, is proposed to enhance system realtime performance by paralleling each module in system. This proposal realizes the function of 2DDCT using two 1DDCT based on Loeffler Fast Algorithm. It obtains a suitable quantification table of traffic image compression in FPGA system through testing a large amount of traffic images, all of which significantly reduce utilization of resource in FPGA system. Proved by the experiments, this system shows the advantages of stability, high image compression quality, high compression ratio and good realtime performance that achieves up to 30 frames/s on processing 720×576 resolution color images. The system can be used as an effective complement to image processing system.

    References | Related Articles | Metrics
    Systems Engineering Theory and Methods
    Effect of Highway Geometric Characteristics on Capacity Loss
    HASHIM Ibrahim Hassan, ABDEL WAHED Talaat Ali
    2012, 12(5): 65-75. 
    Abstract ( )   PDF (546KB) ( )  

    The estimation of roadway capacity is essential in the planning, designing, and operation of highway facilities. This paper aims at assessing the influence of highway geometric characteristics on capacity at tangents and horizontal curves as well as on capacity loss at the change from tangent to curve. Traffic and geometry data obtained from twelve rural, twolane road sites in Minoufiya Governorate, Egypt, were used. Each site consists of a tangent element and the succeeding horizontal curve. Vehicle flows and speeds were collected at each element in the study sites. A capacity estimation method that was based on extrapolation from a fundamental diagram which represented the relationship between traffic flow and density was used. The effect of different vehicle types was accommodated for by converting them into equivalent passenger car units. Regression analysis was used to investigate the relationships between geometric characteristics and capacity. The best regression models for each case (i.e.capacity at tangents, capacity at curves, and capacity loss between the two elements) were introduced. For tangents, the significant independent variables are lane width, shoulder width, and tangent length. In the case of curves, the significant variables are curve radius and lane width. The best model that exhibits the relationship between capacity loss and geometry characteristics includes only curve radius, which functions as an independent variable. The models are very useful and can be used to deal with capacity analysis as well as for the evaluation of rural, twolane roads, especially for the area under study.

    References | Related Articles | Metrics
    Modeling Risk Degree of Conflicts between Crossing Pedestrians and Vehicles at Signalized Intersections
    REN Gang, GU Cheng, LU Li-Li, ZHOU Zhu-Ping, DING Chen-Zi
    2012, 12(5): 76-81. 
    Abstract ( )   PDF (1292KB) ( )  

    To quantitatively evaluate the safety of pedestrian crossing and to quantify the risk degree of traffic conflicts between crossing pedestrian and vehicle at signalized intersection, this paper conducted the risk degree model of crossing pedestrian and vehicle based on the features of pedestrian crossing behavior and the theory of conflict. The SOMK clustering algorithm based on the fuzzy cluster analysis method is used. Evaluation analysis process and results of risk degree model is demonstrated in the case studies of six signalized intersections in Nanjing City of China with the manual data collection method on video, which gives acquisition and calculation method of the evaluation indexes of TTC, PET, DST and validates the practicality of proposed model. The result shows that three indexes (TTC, PET, DST) play a significant role in clustering analysis and the frequency and severity of conflicts differs according to different types of conflict.

    References | Related Articles | Metrics
    Traffic Flow Model for Staggered Intersection without Signal Lamp
    LIU Xiao-Ming, ZHENG Shu-Hui
    2012, 12(5): 82-89. 
    Abstract ( )   PDF (631KB) ( )  

    Traffic characteristics investigation of staggered intersection lays the foundation of scientific and reasonable traffic control strategies. This paper first proposes the cellular automaton rules on the basis of the traffic conflict process analysis. Then with these rules, the traffic flow evolution under different parameters is presented by numerical simulations. The relationship between the arterial road traffic flow density and the average speed is explored. It is revealed that low traffic density on the main road of staggered intersections may lead to traffic congestions on the approach of main road and the road between two Ttype intersections, and the average speed of traffic flow on each Ttype import of main road was affected by the traffic flow changes of the other Ttype approaches. Moreover, the traffic congestion on intersection without signal lamp is presented as a periodically queuingdissipates process. The above methods and results provide meaningful guidance for traffic management and control implementation of staggered intersections without signal lamp.

    References | Related Articles | Metrics
    Traffic Flow Simulationin of a Scenario with Signalized Intersection and Bus Stop
    TIAN Li-Jun
    2012, 12(5): 90-96. 
    Abstract ( )   PDF (3099KB) ( )  

    In the real road traffic system, local congestion always occurs near the intersections or bus stops, which have become the main bottlenecks of urban traffic development. Considering the scenario with signalized intersection and a nearby bus stop, this paper investigates the lanechanging and dwelling behaviors in a twolane mixed traffic and conducted the simulation using a cellular automaton model under open boundary condition. Simulation results show that for different proportions of bus flow over the whole flow, a critical probability sending vehicles into the system exists and represents the decreasing trend with respect to the bus flow proportion. Within the critical value, traffic is always the free flow and the flow increases with the probability; whereas, beyond the critical value, the traffic will be saturated. The paper proposes that during rush hours, the queuing upstream the intersection can stretch to the bus stop and then disturb the normal dwelling operation of buses. Therefore, it is necessary to reasonably design the position of signalized intersection and the corresponding cycle time.

    References | Related Articles | Metrics
    Simulation and Analysis of Traffic Flow Model on Multi-Platform Harbor-Style Bus Stop
    LIU Ying-Dong, NIU Hui-Min
    2012, 12(5): 97-102. 
    Abstract ( )   PDF (881KB) ( )  

    To simulate the mixed traffic flow, the paper proposes a cellular automaton model with multiplatform harborstyle bus stops and two lanes. In the model, the rules of vehicles’ moving, lanechanging and stop time are redefined to accord the reality. It also analyzes the statistical characteristics of traffic flow. The effects of bus parking mode, the length of platform, the platform spacing and the bus proportion on traffic flow are studied, respectively. The results show that the multiplatform harbor-style bus stop has many advantages in bus parking, traffic congestion relieving and traffic flow improving. In summary, the model proposed in this paper is valuable for studying the impacts of public transport on urban traffic flow.

    References | Related Articles | Metrics
    Container Liner Operation Economic Model and the Departure Interval Decision-making
    WANG Wen
    2012, 12(5): 103-109. 
    Abstract ( )   PDF (412KB) ( )  

    To seek the optimal departure interval of container liner operation and related decision variables and find a more economic way for the shipping industry with capital intensive nature, this paper proposes a liner operation economic model. The object is maximal profit from some liner route in a certain operation period and the restrictions are ship load capacity, container quantity of each type and port efficiency of loading and unloading. Based on the container quantity relations among ports on the line, the paper thoroughly analyzes the ship capital cost, operation cost, and voyage variable cost including fuel cost, cargo handling fee, berthing fee, port charges and crew subsidy. It puts forward the harmonic mean method to calculate integrated handling efficiency of different container types at port. And the solution of profit-speed with the conditions keeps a certain amount of fuel on each voyage section and realizes profit at the time of delivery. Therefore, it realizes the consideration of maximizing both daily profit of each voyage section and the total operating profit. It then gets the optimal solution of the decision-making variable by combining implicit function derivation and extreme value solving method of functions, and shows the effectiveness of the model via an example.

    References | Related Articles | Metrics
    Optimization Research of Refueled Scheme Based on Fuel Price Prediction of the Voyage Charter
    JIA Peng, SUN Xue-Shan, YANG Zhong-Zhen
    2012, 12(5): 110-116. 
    Abstract ( )   PDF (992KB) ( )  

    Fuel cost is the key element of ship owners to control operating costs in the business of voyage charter. While fuel price changes frequently over time and also ocean shipping transport cycle is long, and therefore how to develop the most economical refueling scheme among the ports of call becomes one of the significant issues that the ship owners concerning. This study addresses the refueling scheme optimization problem for voyage charter operators from the perspective of the ship owner. First, an ARMAbased model was proposed to forecast a time serials of the fuel prices. Then, to maximize the shipping operation profit, the nonlinear programming model is formulated to solve the optimal refueling scheme where to refuel and how much to refuel. Finally, a case study on a Pacific Oceancircle route under multicharter voyage contracts is conducted for a dry bulk cargo ship. The results indicate that the optimal fuel supply program compared with conventional refueling cost saves 263 400 USD, accounting for 14.3% of the total operating profit.

    References | Related Articles | Metrics
    Flat Car Loading Research Based onSimulated Annealing Hybrid Genetic Algorithm
    GU Liang-Yu, LV Jian-Xin
    2012, 12(5): 117-122. 
    Abstract ( )   PDF (574KB) ( )  

    In view of the highrisk and low efficiency of semitrailer in vehicle transport, the paper proposes the method of transporting the vehicle using flat cars. In railway transportation, how to improve the utilization rate of railway flatcars under military and safe requirements is the key of the loading problem of multipletype flatcars. It develops the mathematical models and proposes an adaptive hybrid genetic algorithm method combining the improved adaptive genetic algorithm, simulative annealing algorithm and best fit decreasing algorithm. It then analyzes the genetic algorithm coding, fitness function, design of genetic operator and the algorithm which adaptively determined the probabilities of crossover and mutation. Through simulation experiments, the fitness and loading order of the equipment curve are obtained. Compare with the hybrid genetic algorithm, the computing process is proved to be fast and accurate.

    References | Related Articles | Metrics
    Collaborative Optimization Model of Empty and Loaded Car Flow Organization for Scheduling System of Collecting and Distributing in Heavy Haul Railway
    JING Yun, HE Shi-Wei, HAO Dong-Hong
    2012, 12(5): 123-129. 
    Abstract ( )   PDF (462KB) ( )  

    The heavy haul railway scheduling system of optimization model of car flow organization should combine with both the empty and loaded car flow. Through analyzing the empty and loaded car flow organization, this paper develops a comprehensive optimization model based on the ability of station and railways. The goal is the minimum turnaround time of cars in the loading end of heavy haul railway. Then, based on the information entropy, representation of affinity degree is proposed. For antibody to the objective function and antigen constraint conditions, the immune clone algorithm is adopted for car flow organization in the loading end of loaded haul railway. In the solving process, premature convergence can be prevented using the immune cloning to achieve reproduction, and using the antibody concentration to control the population size. Finally, the simulation results show that the average search time of the proposed algorithm is reduced by 25% and 49% compared with the GA and PSO.

    References | Related Articles | Metrics
    Construction and Refinement Method of Metrics System
    CONG Wei, HU Ming-Hua, ZHANG Chen-
    2012, 12(5): 130-134. 
    Abstract ( )   PDF (467KB) ( )  

    In recent years, researches on the complexity of air traffic become popular. How to select proper metrics to analyze the complexity is a key technology. In this paper, the importance of metrics selection to the complexity study is explained based on a brief review of previous researches. Combined with existing conclusions, a complexity metrics system is established by selecting metrics which are well-defined and can be quantitatively analyzed. The grey correlation cluster method is used to explore the pattern of the distribution of metrics and refine metrics for the characteristics of multi-dimensional and large amount of information. The refined metrics can both fully describe the problem and reduce the dimensions when analyze air traffic complexity. According to the radar data of 16th sector in Guangzhou region of China, a class of metrics is calculated and cluster analyzed, which verifies the accuracy of this method.

    References | Related Articles | Metrics
    Stochastic Road Network Model and Network Stability Analysis
    XIONG Zhi-Hua
    2012, 12(5): 135-139. 
    Abstract ( )   PDF (516KB) ( )  

    The sources of disruption to road network are numerous and travelers expect not only less travel time but also high reliability under the uncertainty of travel.More than 80 percent of commuters’ route choices rely on travel time reliability as their primary or second factor according to an route choice investigation.Therefore,the combined stochastic road network model is proposed in this paper which adapts travel time reliability and travel time as the main factors to make route choice.The algorithm can be obtained to solve the proposed model with the help of the stochastic user equilibrium (SUE) model.Meanwhile, the entropy can be obtained to show the stability of road network according to the ratio of travel time reliability and travel time among route choice. These are reminiscent of the situation in ITS where users having information care more about travel time reliability and others having no information emphasize on travel time.An example is illustrated and the road network is more stable when the ratio of the user having information reaches a certain value.

    References | Related Articles | Metrics
    Empty and Loaded Container Transportation Optimization Based on Cargo Rank
    DUAN Gang, CHEN Li, LI Yin-Zhen, LI Man-Sheng, HE Rui-Chun
    2012, 12(5): 140-147. 
    Abstract ( )   PDF (409KB) ( )  

    The distribution and flow direction of container freight are significantly different from place to place in China due to the affecting of many factors such as unbalanced distribution of natural resources, the region economy development, city layout and other factors. And this leads to the prominent contradiction between supply and demand of railway container. Therefore, the empty container allocation has become increasingly important. The former optimization models on empty container allocation mostly minimize allocation costs without regarding to loaded container transportation income. The paper addresses the two concerns and formulates a nonlinear integer programming model based on demanding rank of cargo suitable for container and container type. The objective function is maximizing the transportation profit by freight charges subtracting empty container allocation cost. After the empty allocation between different railway bureaus, the empty container demand of the higher rank cargo is more priority than that of the lower rank cargo for the same container type in every container demand station. The model is proved to be validity and feasibility by an example.

    References | Related Articles | Metrics
    Simulation Study on Influence of Information Grading on Day-to-dayRoute Choice
    YANG Fan, WU Jin-Wu, MA Shou-Feng, JIA Ning, ZHONG Shi-Quan
    2012, 12(5): 148-154. 
    Abstract ( )   PDF (662KB) ( )  

    The impact of traffic information on the network has aroused a widespread interest in the academia. Travelers are expected to get detailed information such as flux or velocity in most of the current studies. However, because of the constraint of detecting accuracy, only qualitative information which is divided into a few grades can be published to users in actual situation. Aiming at this, the paper develops a model of travelers’ day-to-day travel decisions making and their perception of traffic information. It then studies travelers’ route choice behavior under the condition of information grading. The results show that information grading can make transportation systems reach stochastic equilibrium quickly, but with the cost of stability decline of the equilibrium. However, compared with the detailed information, the system has less sensitivity on information updating cycle when the grading information is published. It has certain reference value for the practical application of traffic information systems.

    References | Related Articles | Metrics
    Model and Simulation on Passenger Behaviors in Comprehensive Railway Passenger Hubs
    WANG Ai-Li, DONG Bao-Tian, YIN Biao, CHEN Shuan, FENG Ping-Ping
    2012, 12(5): 155-161. 
    Abstract ( )   PDF (1057KB) ( )  

    Based on the concept that pedestrian movements are dominated by some social forces in model, this paper develops the passengers’ behavioral simulation model in railway comprehensive passenger hubs with consideration of the interaction between pedestrians. Because of the individual differences in crowd distribution, this model uses target driving force and acting force between pedestrians or obstacles, extrusion forces and frictions to change the direction and speed of pedestrian movement. With the decision rule of preventing the penetration of pedestrian, the pedestrian overlap is eliminated. The principle of the target local minimum and setting auxiliary target are adopted, which also resolves the problems of dynamic collision avoidance and bypass between pedestrians and the environment. A computer simulation and analysis to Beijing South Railway Station is made to test the proposed model and the results show that the model is logical and effective.

    References | Related Articles | Metrics
    Ramp Design Model for Elevated Road Network in Corridor
    WANG Hua, ZHANG Xiao-Ning
    2012, 12(5): 162-167. 
    Abstract ( )   PDF (485KB) ( )  

    Regarding the ramp design problem in the elevated road network, the ramp location always affects the network performance and whether there exists a design paradox. This paper investigates the ramp design problem by optimizing the ramp location and its capacity simultaneously. The ramp design paradox in urban elevated road network and its intrinsic reason are also discussed. A ramp design model is proposed as the bilevel programming considering the importance of ramp location for the elevated road network in a corridor. The design variables in the bilevel programming are ramp location, ramp capacity and ramp type. The design objective in upper level is to minimize the total travel cost in the network, and the traffic assignment in low level is user equilibrium problem. In the last section, numerical examples are conducted to demonstrate the merits of the proposed model. Meanwhile, some numerical results show that the proposed model guarantees promising effects.

    References | Related Articles | Metrics
    Modification and Pedestrian Simulation of Platform Width Calculation Method of Urban Rail Transit
    WANG Zi-Jia, CHEN Feng, LI Xiao-Hong
    2012, 12(5): 168-173. 
    Abstract ( )   PDF (702KB) ( )  

    Based on the current related research and field studies, this paper proposes the calculation method of boarding and alighting area width of platform in the current design manual for urban rail transit. Taking some design manuals of other countries as reference, a modified method is proposed. The new method can reduce the width of the designed platform and the scale of the station. Quantitative analysis should be conducted to determine if the modification significantly affects the circulation of platform before the modified method applied. The pedestrian simulation environment is built according to the stations designed by the original method and the modified one using computer pedestrian simulation tool. The simulation evaluation is also conducted. The evaluation index including pedestrian density, time lost and walking time. Comparisons illustrate that the capacity of the stairway and escalator on the platform determines the circulation efficiency. The modified method can decrease the platform width with little sacrifice of level of service.

    References | Related Articles | Metrics
    Cases Analysis
    Traffic Organization Optimization of  Changhongqiao through Microscopic Simulation
    WANG Ming-Zhe, GUO Min
    2012, 12(5): 174-178. 
    Abstract ( )   PDF (406KB) ( )  

    With sharp growth of motor vehicle ownership, traffic congestion has become a common problem in metropolitans. However, intersections, the nodes of the urban road network, are always regarded as the bottlenecks of the network. Reducing traffic delays in intersections is the key to improve the total operation efficiency of road network. This paper conducts a case study of the intersection traffic problems in Beijing. Some management schemes are proposed to improve the safety caused by traffic conflicts and to reduce delays at the intersections. With microscopic simulations, the schemes are evaluated and selected quantificationally. The simulation identifies four improvement measures perform well in alleviating the conflicts in intersections and reducing the vehicle delay from the different ways.

    References | Related Articles | Metrics
    Applicable Conditions and Implementing Effect of Urban TDM Policy
    GAN Yong-Hua
    2012, 12(5): 179-184. 
    Abstract ( )   PDF (397KB) ( )  

    Because of the accelerating the process of urbanization, sharp increase of the motorized travel volumes, and less potential for transportation construction, the urban traffic problems environmental pollution has attracted considerable attentions. This paper discusses the urban traffic demand management (TDM) policy system of China, and its implementation objectives and measures. It is presented from three aspects of affecting travel generation, travel mode choice and the choices of travel route and time. It also investigates successful cases both in China and other countries’ cities’, The measures, applicable conditions and implement effects of each kind of traffic policies is analyzed systematically, such as coordinated development of transport and land use, public transport priority, road congestion pricing. Welldeveloped public transport system, advanced traffic information, and the combination of a number of policy implementation are found to be the common characteristics of successful TDM implementation.

    References | Related Articles | Metrics
    Transportation Industry Imput and Output Analysis of US, Japan, UK and Australia
    DUAN Xin, SUI Li-Na, WU Dan-Dan
    2012, 12(5): 185-190. 
    Abstract ( )   PDF (368KB) ( )  

    Developing tertiary industry is the key economic development strategy made by China government. As the traditional industry and forerunner industry, transportation has been the priority to the development based on its features of basic industry and properties of service economy. If economic structure shift to the modern tertiary industry, it should be necessary to propose suitable and available strategy and policies concerning in feature and rules of transportation historical development. OECD is an orgnization of highly advantage in marketoriented economy, thus tracking the transportation character of the OECD of typical Countries has high reference values to understand transportation industry properties and development law. This paper uses the methodology based on the IO analysis to analyze transportation’s function location and roles in US, Japin, UK and Australia via direct input coefficients, cumulative input coefficients, influence coefficient, induction coefficients. Results of the study may provid experiences and lessons for transportation development in China.

    References | Related Articles | Metrics
    Key Indicators of Transportation State “863 Project” Performance Evaluations
    HUANG Ling
    2012, 12(5): 191-197. 
    Abstract ( )   PDF (505KB) ( )  

    Since the 11thFive  year Plan, Chinese government has launched State Hitech R&D (863) projects for, which aims to improve the development of transportation technology. This paper discusses the performance indicators system of 863 projects in the transportation field in terms of objective management. Based on issues existing in current project evaluation, some new indicators are introduced, which are employed to evaluate the correlation between achievements of project and research objective as well as key technology, rationality of check indices setup, and maneuverability of check process respectively. An evaluation model and its modification approach are also proposed. Finally, taking evaluation of 863 projects in the transportation field as an example, the credibility of the approaches is presented.

    References | Related Articles | Metrics