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    Decision-making Forum
    Future Development of Megalopolis’ Public Transport Systems
    ZHANG Guo-wu
    2010, 10(4): 1-12 . 
    Abstract ( )   PDF (2163KB) ( )  
    The 19th Conference of “Traffic and Transportation Forum 7+1” focused on the future development of megalopolis’ public transport systems. Ensuring priority to the development of urban public transport system has been recognized as an initial way of solving the traffic problems in large cities thanks to the large capacity, high efficiency, energy efficient, and environmental friendly of public transport. The traffic development of several large cities were addressed, namely, applied measurements in the period of post-Olympics of Beijing city, urban traffic scheme in Shanghai World Expo, and traffic management for Guangzhou Asian Games. The important role of the rail transit and bus were also analyzed for such megalopolis alike. The relationships among the private car, bicycle, and public transport are also discussed. A valuable concept was put forward: urban transport system should be developed with system theory, which should be considered and implemented from the just beginning such as the preliminary planning of one city.
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    Forum about Comprehensive Transportation System
    Evaluation Architecture Discussion of Route-Level Transit Service Quality
    YANG Xiao-guang,AN Jian,LIU Hao-de, TENG Jing, ZHANG Dong
    2010, 10(4): 13-21 . 
    Abstract ( )   PDF (1651KB) ( )  
    In this research, travelers’ responses to transportation service according to their budgets on travel time, money and energy expenditure are studied based on the analysis of intrinsic characteristics of transportation service and travelers. A new perspective of evaluating the route-level transit service quality, which is distinguished from that of network-level, is discussed with recommended system architecture, established based on value, energy expenditure, and information dimensions. Finally, suggestions of future work is given, in which, paying more attention to the ergonomic and psychological perspectives of travel issue is encouraged for revealing travel behavior from a more fundamental level, as well as providing theoretical support to the evaluation of transit service quality from passengers’ perception.
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    The Strategy Research on Improving Transport Efficiency and Logistics Performance
    FANG Lun
    2010, 10(4): 22-26 . 
    Abstract ( )   PDF (893KB) ( )  
    According to the logistics economics principle, this paper illustrates that the higher cost and lower efficiency of cargo transport system are main reasons of the unsatisfactory logistics performance through evaluating the Chinese logistics cost proportion to GDP and its composition. Then, it deeply analyzes important influencing factors to transport cost and efficiency both from the macro and micro aspects, including the institution reform, policy adjusting, operational pattern and technique innovation, staffs quality, and so on. Based on that, three strategy suggestions are put forward, namely, (1) innovation of mechanism and policy is the key to reform the transport system; (2) the container multi-modal transport system is an essential part of the integrated transportation system; (3) adopting the advanced logistics technique and operational pattern, the key point is upgrading cargo transport industry level of informatization and standardization.
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    Intelligent Transportation System and Information Technology
    Background Updating Technique in Complex Traffic Scene Based on Sensor Fusion
    WANG Guo-lin, XIAO De-yun
    2010, 10(4): 27-32 . 
    Abstract ( )   PDF (1698KB) ( )  
    The challenges of constructing complex traffic background discourage the application of video surveillance approaches. To solve the problems, a novel background updating method based on sensors fusion is proposed. First of all, a Gaussian mixture model based on expectation-maximization (EM) algorithm is proposed to improve the accuracy of background modeling. Secondly, for slowly moving or stationary region of interest, different sample frequencies are set to increase the reliability of modeling data. Meanwhile, data from loop and virtual loop fusion is performed to enhance the accuracy of vehicle speed detected by virtual loop. A local stationary optimal Kalman smoother is introduced to improve the self-tuning ability of the data fusion algorithm. Finally, experimental results prove the validness and robustness of the method.
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    Design of Safety-Risk-Management Information System for Urban Rail Transit Construction Based on GIS
    WANG Yan-hui, LUO Jun,ZHANG Chen-chen
    2010, 10(4): 33-37 . 
    Abstract ( )   PDF (748KB) ( )  
    The construction of urban mass transit is a project with high-risk, high-investment, long-cycle, and high-impact. As the urban rail transit developed, the great mass of technique and methods in construction project, however, the information management levels are stuck in a micro-level for data management, the global management of risk, the deep use and integrated show of safe data has become the bottleneck of information management of urban rail transit construction. Therefore, in this paper, the safety-risk-management information system for urban rail transit construction based on GIS is presented, and such aspects as system function, system architecture, and process of implement is addressed. The developing work of the system has been completed currently, and the system has been successfully applied in the construction of Tianjin railway
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    The Minimum Sample Size Determination of Floating Car in Beijing Expressway
    XIONG Juan, LIU Jing, GUAN Ji-zhen, SUN Jian-ping, LIU Xue-jie,WEN Hui-min
    2010, 10(4): 38-43 . 
    Abstract ( )   PDF (1004KB) ( )  
    To ensure the accuracy and reliability of the information provided by floating car data (FCD), the paper considered remote traffic microwave sensor (RTMS) data as the real data to verify the validity of FCD. Then the different correlation coefficient between the gradually decreasing FCD via simple random sampling method and RTMS was calculated. Finally, the minimum sample size was obtained which guaranteed the validity of FCD. Furthermore, this results showed that 7 to 9 FCD are needed in Beijing Zhanxi Rd network’s 2nd ring Rd and 3rd ring Rd every kilometer in 5 minutes, and the current sample size FCD can meet the minimum sample size requirements by 73% and 87% in time and in space separately.
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    Application of Simultaneous Perturbation Stochastic Approximation Algorithm in Parameter Calibration of VISSIM Microscope Simulation Model
    ZHANG Yu, YU Lei,ZHAO Na-le,ZHU Li-ying,CHEN Xu-mei
    2010, 10(4): 44-49 . 
    Abstract ( )   PDF (656KB) ( )  
    Microscopic traffic simulation models have been widely applied in transportation management, control, and optimization. However, since the calibration of parameters of microscopic traffic simulation models is a complex and systematic process, the time to complete the calibration is usually long and it is difficult to find the optimal solution, especially for the large and complex network. This paper first selects the widely used VISSIM model as the basic platform for the parameter calibration. Then a parameter calibration approach based on simultaneous perturbation stochastic approximation (SPSA) algorithm is proposed and a corresponding automatic calibration procedure is developed. Finally, the proposed approach is applied to the driving behavior parameter calibration of the simulation model for the expressway
    road network of Beijing, in which the sum of squared relative errors of the speed is used as the objective function. After a comparison of the fitness values of genetic algorithm (GA) and SPSA algorithm, it is shown that the convergence of the SPSA algorithm is 1.7 times faster than that of the GA algorithm, and the squared relative errors of traffic volumes using SPSA algorithm are 0.16 smaller than those using GA algorithm, which validates the advantage of SPSA algorithm in VISSIM parameter calibration.
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    Systems Engineering Theory and Methods
    Methodology for Determination of Concentration of Heterogeneous Traffic
    ARASAN V.T.,DHIVYA G
    2010, 10(4): 50-61 . 
    Abstract ( )   PDF (1706KB) ( )  
    Traffic density provides an indication of the level of service being provided to the road users. When the length and speed of the vehicles in a traffic stream varies significantly, however, it has been, found that, the concept of occupancy, rather than density, is more appropriate to describe traffic concentration. This is because of the reason that occupancy takes into account the variation in the speed and length of vehicles in its measurement. The value of occupancy, however, changes with change in the detection-zone length. Also, the measure, occupancy is not appropriate under heterogeneous traffic conditions, as the traffic has no lane discipline and hence, it is necessary to consider the whole of the width of the road as single unit to analyze the traffic flow. Hence, a new concept named, “area-occupancy” is proposed. Simulation technique has been used to validate the concept of area-occupancy. To check for the validity of the concept, the occupancy and area-occupancy of a homogeneous traffic stream were related to the density of the stream and it was found that area-occupancy can be a substitute for occupancy. Then, the concept of area-occupancy was applied for heterogeneous traffic and a relationship was developed between area-occupancy and traffic stream speed. The developed relationship is found to be logical indicating the appropriateness of the area-occupancy concept for heterogeneous traffic conditions.
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    Daily Travel Time Analysis with Duration Model
    JUAN Zhi-cai,XIANYU Jian-chuan
    2010, 10(4): 62-67 . 
    Abstract ( )   PDF (662KB) ( )  
    Travel demand management strategies and transportation control measures are inherently linked to the time dimension. In this paper, the duration model approach, which integrates the notion of the temporal dynamics, is applied to analyze the commuters’ daily travel time cost. The relationships between daily travel time and sociodemographic attributes and activity and travel characteristics are explored. The time use pattern is partly represented by the derivative and competing relationships of activity and travel. The research results indicate that the behavior of most commuters can be described by travel time minimization mechanism. This research enriches the quantitative analysis method of travel time and is of great importance for a precise understanding of commuters’ time allocation behavior.
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    Chaotic Phenomena and Quantitative Analysis of Aftereffect Delay Spread Time on Flights
    ZHENG Pan,HU Si-ji,ZHANG Chen
    2010, 10(4): 68-72 . 
    Abstract ( )   PDF (589KB) ( )  
    As the number of uncertain factors could result in flight delays into the gate, and in two adjacent flights delayed flights ahead will be spread to different levels of rear flight plans to arrive time. To study the law of spread time of flight delays, in this paper, the flight delayed after-effect spread time calculation method was proposed, and the time series of after-effect delay spread time was calculated using delay time distribution of the flights assigned gate in airport and random delay in flights, then to time series information on reserves can be fully reflected, the paper used embedding theorem for state space reconstruction to be a series of phase points, through these phase points , it can be calculated that the parameters of chaos that is the correlation dimension and the Lyapunov exponent. Finally, the chaos parameters were calculated on the G-P algorithm and a small-data method, then chaotic phenomena of the time series was certificated.
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    Urban Traffic Flow Prediction with Variable Cell Transmission Model
    HU Xiao-jian, WANG Wei, SHENG Hui
    2010, 10(4): 73-78 . 
    Abstract ( )   PDF (673KB) ( )  
    The real-time and reliable urban traffic flow prediction is the foundation of traffic management and control in the urban traffic. A variable cell transmission model (VCTM) is proposed to improve the ability of the urban traffic flow prediction. Based on the analysis of the defects using the cell transmission model (CTM) to predict the urban traffic flow, two parameters are introduced into the VCTM according to the traffic flow conservation law. In the VCTM, three different types of cell connections are described by three different expressions including simple connection, merge connection and diverge connection. Two parameters of the VCTM increase computational burden, but the cell length is adjustable which ensures that the VCTM can be widely utilized in the roads with different lengths. The simulation results indicate that the VCTM meets the requirements of the traffic flow prediction in the urban traffic.
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    Day-To-Day Route Choice Decision Simulation Based on Dynamic Feedback Information
    TIAN Li-jun,HUANG Hai-jun,LIU Tian-liang
    2010, 10(4): 79-85 . 
    Abstract ( )   PDF (962KB) ( )  
    In reality, the individual’s day-to-day route choice behavior is a long-time evolution process, and travelers choose their traveling routes according to the combination of historical experience and real-time traffic information. Considering two classes of users, one equipped with advanced traveler information systems (ATIS) and the other without, this paper investigates the travel efficiency under two different information feedback strategies, namely, travel time feedback strategy and mean velocity feedback strategy. The simulation results given by the cellular automaton model show that the more users rely on historical experience, the quicker the system evolves to the equilibrium. To all users, the travel efficiency decreases with travel demand and firstly increases then decreases with the dependent degree to historical experience. However, as far as the ATIS market penetration rate is concerned, the users’ travel efficiency under two feedback strategies exhibits different trends. The equipped travelers have shorter travel time, particularly under mean velocity feedback strategy. In addition, the difference of travel efficiencies between two classes of users decreases as days evolve.
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    Route Choice Evolving Under Adaptive Rule
    WANG Pu, SUN Hui-jun
    2010, 10(4): 86-92 . 
    Abstract ( )   PDF (868KB) ( )  
    The paper investigates the route choice flows by considering the characteristics of the individual travel’s behaviors Based on the adaptive rule the evolution of the route choice with variable OD demands is discussed. The results show that the flows of each route are convergent for both fixed and variable OD demands. For the fixed mean of the OD demands with the increase of the variance, the convergent speed becomes slower. Moreover, for the fixed variance, increasing the mean can not affect the convergent speed, but it may lead to more serious fluctuations of the route flow. In addition, by considering three traffic modes the paper presents a new route choice evolving model. The results show that the stability and autonomy of travel by car are higher than those of travel by bus.
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    Development and Inspiration of Road Congestion Pricing Revenue Redistribution Theory Research
    ZHAO Ze-bin, AN Shi, WANG Jian
    2010, 10(4): 93-100 . 
    Abstract ( )   PDF (1326KB) ( )  
    Road congestion pricing revenue redistribution is the key problem and frontier research of road congestion pricing development. This Paper reviews the history and latest achievements of the social welfare theory, public support theory, and revenue redistribution strategy theory which are related to road congestion pricing revenue redistribution. Then, suggestions of the implementation in urban road communication are proposed. The theory research and practice of road congestion pricing revenue redistribution indicate that policy suggestions and corresponding methods of implementation of this strategy should be presented aiming at resolving the unfair problem of welfare redistribution and enlisting support of public based on the consideration of traffic efficiency firstly. This strategy is proved to be effective in enhancing the feasibility and validity of road congestion pricing strategy, and moreover in improving the road congestion and increasing the transportation efficiency.
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    Road Traffic Accidents Model and Its Application Based on Driver’s Self-Mistakes
    MA Yan-li, LOU Yan-jiang,WANG Yao-wu
    2010, 10(4): 101-105 . 
    Abstract ( )   PDF (599KB) ( )  
    To improve the traditional analysis method of driver accident, the paper analyzes the cases of road accidents and survey data from the microscopic aspect. An accident causes model is formulated to describe the drivers’ own mistake characteristics and its relation with the road traffic accidents. The weights of key influencing factors are determined by the improved AHP method and its influencing level is quantitatively analyzed. The improved AHP method reduces the impact of subjective factors on the analysis accuracy. Results show that drivers’ error rate of perception is approaching 50.2%; the error rate of judgment is 38.9%, and the operational error rate accounts for only 10.9%. The main factors cause traffic accidents are drivers’ low abilities to perceive and judge risk and accident. The results provide the scientific basis for the drivers’ self-mistakes and accident prevention.
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    Algorithm of Short-Term Traffic Flow Forecasting Using Fractal Theory
    CHENG Xiang-jun, LIU Jun, MA Min-shu
    2010, 10(4): 106-110 . 
    Abstract ( )   PDF (480KB) ( )  
    Short-term traffic flow forecasting is the foundation of urban traffic control and guidance. When prediction period is shorter than 5 min, the precision of normal methods for short-term traffic flow forecasting are often difficult to satisfy the actual requirement. To improve the accuracy of short-term traffic flow prediction, considering the non-linear characteristics of short-term traffic flow, the algorithm based-on fractal theory was applied to shorten prediction time and improve the accuracy of forecasting. On the basis of the Grassberger-Procaccis (G-P) algorithm, Euclidean modular is applied to define the distance between any two points in phase space. Sifting method is adopted to calculate the Euclidean distance of selected points to increase the speed of computing. Thus, it is possible to forecast traffic flow within 2 min. Using the data of 24 hours in the segment of Xizhimen to Fuchengmen in Beijing as instance, the forecasting approach based-on fractal was applied to predict the last 30 points in data sequence with 712 effective points and the prediction precision is more than 92%.
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    Bi-Level Programming Model and Algorithm for Transportation Network Design Problem Considering Sustainable Development
    QIN Jin, NI Ling-lin,DONG Long-yun, SHI Feng,MIAO Li-xin
    2010, 10(4): 111-117 . 
    Abstract ( )   PDF (946KB) ( )  
    The paper presents the optimal model and algorithm of mixed transportation network design problem considering the sustainable development. The decision-making variables of road level status are used to make the mixed network discrete, and the bi-level programming model is used to describe the problem. The objective of the upper model is to minimize the total investment and emission of cars. The constraint conditions are set as the expropriation of the transportation network and the degree of traffic congestion of the roads. The determinate user equilibrium assignment is selected as the lower level model. The simulated annealing algorithm and the path-based gradient project algorithm are used to solve the upper and lower model respectively based on the attribute of the model. The results of numerical example show that the congestion is relaxed observably and the emission of cars are decreased substantially in the optimized network, which indicates the model and algorithm are available for road network design considering sustainable development.
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    The National Highway Network Layout Optimization Based on Combination Optimization Model
    ZHU Nuo,WEI Li-ying, SHAO Chun-fu, JIA Bin
    2010, 10(4): 118-124 . 
    Abstract ( )   PDF (931KB) ( )  
    Based on the traditional highway network layout combined optimization model, the paper modified the model of importance degree of node, segment, and network. Considering nodes’ transportation level and distribution of network traffic demand between nodes, the paper put forward traffic volume of passenger and freight as the important index of degree of importance of node, and took the flow, length and the number of nodes which directly connected into the degree of importance model of segment, then introduced it into the objective function. Finally, it established highway network layout combined optimization model which is fit the national level highway network, the geneitc algorithms is applied to highway network layout optimization problem. A simulation test for Northeast China expressway network planning project was also made by the model. The results indicate that the models are feasible and effective, and they provided references for highway network planning.
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    Optimization of Emergency Vehicle Scheduling Model
    ZHAO Han-tao,ZHAI Jing, MAO Hong-yan,HOU Ya-li
    2010, 10(4): 125-130 . 
    Abstract ( )   PDF (931KB) ( )  
    Optimization of emergency vehicle scheduling is an effective way to reduce heavy casualties and property losses caused by incidents. Based on the analysis of the scheduling problem, decision variables, and objective function, the ideal scheduling model is formulated by minimizing the overall loss. As the model parameters are usually difficult to determine, the generalized response time is regarded as decision-making object and the real-time traffic conditions are set as a decision-making complement. Then a simplified optimization model is established by simplifying constraint conditions. Calculation of link travel time and intersection travel time is analyzed, and road service level is divided based on road traffic with urban emergency vehicle. As a result, the research based on the case of Weihai city in Shandong province shows that the simplified model is able to support an emergency vehicle scheduling optimization program, which proves the effectiveness of the proposed method.
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    Time-Varying Evacuation Demand Forecasting Model for Emergency Traffic with Multiple Assembly Locations
    GENG Yan-bin,WEI Xian-lan
    2010, 10(4): 131-136 . 
    Abstract ( )   PDF (789KB) ( )  
    This paper focuses on the method to forecast time-varying emergency traffic demand distribution. With analyzing the characteristics of emergency traffic demand, through a synthesis of existing relative references, it proposes the generalized S-curve concept for behavioral responses. Subsequently, according to the characteristics of the different evacuation time limit requirements and reaction parameters of each assembly location, a generalized S-type behavioral response curve analysis model is presented, while, the calculation method of evacuation time curve in unit-period is designed. Furthermore, by applying the above-mentioned methods, the algorithm for calculating the emergency traffic OD demand matrix in different period is presented to develop the time-varying emergency traffic demand distribution model. Finally, after a MATLAB-based software model is programmed, the test on the given example demonstrates that the proposed models accurately illustrate the dynamic changes of the emergency demands evacuation percentages in each period for all assembly locations and the entire system. It can also be applied to effectively forecast the time-varying emergency traffic demand distribution.
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    Evolutionary Game of Speeding Driving Behavior
    LI Zhen-long, ZHANG Li-guo
    2010, 10(4): 137-142 . 
    Abstract ( )   PDF (789KB) ( )  
    Decision-making model of speeding and no speeding of drivers and inspection and no inspection of traffic mangers is proposed aiming at the speeding behavior of drivers. The evolutionary process that traffic mangers and drivers choose strategies is analyzed using evolutionary game. The possible evolutionary stable states are analyzed accordingly to local stability of Jacobian matrix. The evolutionary stable state has several kind conditions such as saddle point, stability point and instability point because of traffic mangers and drivers’ different benefit. The results show that government department must reward traffic mangers for doing their duty and punish traffic mangers for their breach of duty to urge traffic mangers to inspect strictly. At the same time, the speeding drivers should be punished strictly according to individual difference. Thus speeding driving can be forbidden to a certain extent and improve traffic safety.
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    Performance Evaluation Method of Public Transit Routes Based on BCC Model
    YAN Ya-dan, GUO Xiu-cheng, YE Mao
    2010, 10(4): 143-147 . 
    Abstract ( )   PDF (714KB) ( )  
    Due to shortages of public funds and expanding social needs, maintaining and improving the performance of public transit routes are critical for future operation. Based on the characteristics of the urban public transit system, a concept framework of performance evaluation of a single bus routes is established from the service providers and the users perspective. The process of service implementation is divided into two stages. The BCC model that was first put forward by Banker, Charnes, and Cooper in 1984 is based on the data envelopment analysis (DEA) and is used to calculate the operation efficiency and the service effectiveness. Ten bus routes of Taizhou, China are selected for the practical application.
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    Vehicle Routing Problem Based on Object-Oriented Discrete Event Simulation
    SUN Zhong-yue, GUAN Zhong-liang, HE Shao-en, GUO Zhi-guang
    2010, 10(4): 148-154 . 
    Abstract ( )   PDF (873KB) ( )  
    A new solution for vehicle routing problem (VRP) is proposed in view of its complexity. First, discrete event simulation model of customer’s distribution process is established. In this model, the events of distribution process and resources have been described by the object-oriented approach. A variety of constraints which VRP problem involves is processed in the simulation. The model simulates complicated vehicle delivery process. Then discrete event simulation results are optimized by the genetic algorithm. The optimal solution of VRP is finally obtained. The method which combines genetic algorithm with discrete event simulation technique can effectively overcome the disadvantages that the exact algorithms and intelligent heuristics algorithms are difficult to solve vehicle routing problem with multiple constraints. The experimental results prove the feasibility and effectiveness of the proposed method. As the simulation results can document the whole distribution process in detail, this method has some significance to the practical application of vehicle routing problem.
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    Location Model of Transport Junction in Economic Circle and Its Algorithm
    ZHANG Bing,DENG Wei
    2010, 10(4): 155-160 . 
    Abstract ( )   PDF (907KB) ( )  
    Transport junction location problem has been a lot of relevant research at home and abroad, but the traditional location model rarely has taken into account the economic influence factor of the cites where the transport junction was located. On the basis of analyzing the internal relation between economic development of cities and transport junction in the economic circle, this paper introduced the six factors that influenced economic development level of cities in the economic circle and developed a Bi-Level programming modal with the minimization of the transportation costs and the junction construction costs, the maximization of economic influence of the cities where the junction was located, and considering the traffic equilibrium on the roads in economic circle. Hybrid niche genetic simulated annealing algorithm was proposed for solving the model quickly, which was programmable and practicability. Thereafter, the validity and practicability of the proposed model were demonstrated by the example of transport junction location in the economic circle of Yangtze River Delta.
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    Dynamic Exit Speed-Control Model of Hump Skating
    ZHANG Hong-liang, YANG Hao,ZHANG Chao,WEI Yu-guang, GAO Yong-ling
    2010, 10(4): 161-165 . 
    Abstract ( )   PDF (626KB) ( )  
    Based on practical issues found in field investigation, the reasons of over-speed coupling of new heavy axle load cars were analyzed deeply, and so were that for inadequate rolling of light-load cars under unfavorable condition. The reason found to be that, the traditional exit-speed-control model for hump skating has unreasonable basic resistance value for exit speed calculation, and ignore the environmental impact. To resolve these problems, the concept of the unit co-resistance was put forward, and a dynamic interval speed-control model has established based on the energy conservation law. Moreover, based on uncertain information processing ability of fuzzy logic and self-learning ability of neural network, a target speed-control model based on fuzzy neural networks was established. Finally, a hump was taken as an example to validate the models, which provided reference for speed controlling of hump car-unit rolling.
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    Application of Catastrophe Theory in Urban Passenger Transport Structure Evaluation
    WU Chen, CHENG Lin
    2010, 10(4): 166-171 . 
    Abstract ( )   PDF (663KB) ( )  
    According to the basic principles of catastrophe theory, the evaluation indices are determined from three aspects: residents’ satisfaction, economy benefit, and sustainable development. The definition method of qualitative indices is also presented. Three elementary forms of catastrophe, such as, cusp, butterfly, and swallowtail are used to measure the membership function values of different traffic mode. However, these forms are hierarchical and vary in complexity of the control variables. Furthermore, to solve the problem of catastrophe evaluation value, this paper puts forward a new transformation way named linear equation. This method is applied to evaluate the passenger transport structure of Huainan city in Anhui province, and the results indicate that the evaluation method is feasible and matching well with real conditions.
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    Cases Analysis
    Transportation Characteristics Research of Spectators in Big Events
    GUO Ji-fu, SUN Zhuang-zhi, YAO Guang-zheng, LIU Xue-jie, HU Xin-yu
    2010, 10(4): 172-178 . 
    Abstract ( )   PDF (1433KB) ( )  
    The paper focuses on transportation modes of spectators which are important to transportation management of big events. Surveys were conducted in six venues during the 29th Olympic Games. The changes of transportation modes in the same venue before and during the Olympic Games are also investigated (including the Olympic Green during “Good Luck Beijing” sport events, rehearsals, the Opening and Closing Ceremonies, and the Olympic sport events). The survey data reveal the impact of venue locations and traffic infrastructure on transportation modes; besides, with the same traffic infrastructure, private cars and taxis were greatly reduced by taking measures in traffic demand management and traffic management. The paper offers experiences and data references to transportation management of other big events.
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    Safety of Cross-Section on Two-Lane Highways in Mountainous Areas
    ZHANG Tie-jun,TANG Cheng-cheng,WANG Rong-rong
    2010, 10(4): 179-185 . 
    Abstract ( )   PDF (865KB) ( )  
    The width of subgrade and shoulder has strong relationship with the safety and capacity of two-lane highways in mountainous areas. On the basis of the survey data collected from 24 two-lane highways in mountainous areas, the paper explores the relevant safety factors in this kind of area. It analyzes the relationships of all accidents, injury accidents, rear accidents, roadside accidents and collision accidents with the factors of subgrade and shoulder. Negative Binomial regressions are applied to fit the total crashes with subgrade width, truck proportion, and other factors. The results indicate that all kinds of accidents increase first and decrease then with the increases of subgrade and shoulder width. In the rear-end prediction model, several factors like the propitiation of truck and entrances lead to more rear-end crashes, and the increase of subgrade width reduce the probabilities of rear-end crashes.
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    Modeling and Simulating of Flow Field for Aircraft Wake Vortex
    WEI Zhi-qiang, XU Xiao-hao
    2010, 10(4): 186-191 . 
    Abstract ( )   PDF (697KB) ( )  
    The wake vortex induced by the leading aircraft usually brings the dangerous state to the following aircraft such as incline, rolling, or stall. Based on the anglicizing of mechanism of wake vortex, the decaying and movement models are developed in this paper. In addition, using the methods of image vortex and considering the influence of ground effects, the paper determins the degree of influence by the increasing of space between the vortexes, which is suitable for anglicizing the influences of ground effects. With these models and methods, the filed of wake vortex is simulated and calculated, the results are similar to what calculated by the Large Eddy Simulation models and measured by the lidars. With the advantage of simple form, high speed, the proposed models can be used in the study of wake vortex safety spacing system of airport.
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    Integrity and Continuity Analysis of INS/GNSS Based on RNP RNAV
    QU Zhong-jun,WEI Quan-hu
    2010, 10(4): 192-198 . 
    Abstract ( )   PDF (879KB) ( )  
    This paper presents a general analysis method (process) of integrity and continuity based on the RNP technology which was sponsored by the ICAO (International Civil Aviation Organization). The integrity and continuity results of two types of system configuration are obtained by detailed analysis on navigation system configuration and redundant INS/GNSS system. The results show that whole system’s integrity and continuity has relationship with structure configuration. The system continuity is not improved by merely adding navigation modula. Other relative devices, for example, navigation displays and navigation computers also affect integrity and continuity of system. Also, the three-ply INS/GNSS system, dual navigation displays and dual computers design configuration can meet integrity and continuity requirements of RNP-0.5 (required navigation performance).
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