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25 June 2011, Volume 11 Issue 3 Previous Issue    Next Issue
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Forum about Comprehensive Transportation System
Intelligent Transportation System and Information Technology
Systems Engineering Theory and Methods
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Forum about Comprehensive Transportation System

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Elasticity-Based Model Applies in the Forecasting of Highway Induced Traffic ZHAO Sheng-chuan, HE Nan 2011, 11(3): 1-7.  Abstract ( )   Induced traffic is a key part of travel demand analysis, which directly affects the urban transportation planning. The purpose of this paper is to address the question of how much new or improved road induces extra traffic. Based on the concept and mechanism of induced traffic, the factors that affect vehicle-miles of travel (VMT) are discussed. The elasticity-based model which is in general use is applied in the calculation of our provinces and cities. In accordance with the data collection (from 1990 to 2008), induced traffic is analyzed. And then the elastic coefficient of our country and six districts (north China, east China, southwest China, south central China, northeast China, and northwest China) between VMT and lane-miles is estimated to be 0.16-0.51. Considering time delay, the elastic coefficient with one year lag and two year lag is about 0.22-0.54. The data analysis not only confirms the existence of induced traffic, but also provides substantive recommendations to urban transportation planning. Related Articles | Metrics

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Urban Agglomeration Transport Planning Based on System Dynamics DONG Yan-hua 2011, 11(3): 8-13.  Abstract ( )   Due to incompletion of comprehensive transport management system reform, and lack of single administration entity in urban agglomeration, different modes of transport planning established by separate government sectors in charge are hard to be suited and connected. Moreover, comprehensive transport development in urban agglomeration is increasingly restricted by resources and environments. The breakthroughs of conception, methodology, and technology of comprehensive transport planning in urban agglomeration are urgently needed. This paper applies thoughts and methods of system dynamics into comprehensive transport planning in urban agglomeration. It analyzes the feedback relations between transport and regional economy from three aspects, namely, investment effect, operation effective, and placement guidance effect. It also establishes causal relationship flow chart between transport system and urban agglomeration development and defines and describes major subsystems and functions. The roles of this method are discussed for creating comprehensive transport planning in urban agglomeration restricted by resources and environments. Related Articles | Metrics

Intelligent Transportation System and Information Technology

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A Calibration Method of Microscopic Simulation Models for Mixed Traffic Flow LI Jia, WANG Zi-bang, DONG Hai-wen 2011, 11(3): 14-20.  Abstract ( )   A microscopic method may generate more accurate results in simulation model calibration for the mixed traffic flow with greatly different vehicle characteristics. In this paper, a method for mixed traffic flow is developed, which focuses on sensitivity analysis of model parameters, parameters values calibration, and result evaluations, for different vehicle and link types. An example of calibrating microscopic simulation models is carried out using CORSIM. The results show that, when the average travel time in CORSIM is satisfied with the targets, vehicle-type calibration can effectively calibrate the discrepancy between CORSIM and the actual one, and keep the simulated vehicle types in line with actual vehicle types. The method is proven to be effective. Related Articles | Metrics

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Evaluation of Social-Economic Benefits to Beijing ITMS HUANG Ai-ling, LIU Yun-he, WU Yue 2011, 11(3): 21-26.  Abstract ( )   The application of intelligent transportation management system (ITMS) in Beijing has created a series of positive social-economic benefits. Because of the openness and complexity, many evaluation indexes are difficult to quantify and how to quantize the benefits has become an urgent problem. The paper analyzes the social-economic benefits to Beijing ITMS after its application in 2008 in reducing the cost of vehicle operation, saving travel time for travelers, decreasing the investment of land resources and transportation infrastructures, promoting the development of relative industries and technology progress, and so on. Based on the data concerned, the paper makes quantitative and qualitative analysis of its social-economic benefits by with and without project comparison method, econometrics and human capital, then gets the conclusion which will be a reference for evaluation and decision-making of intelligent transportation. Related Articles | Metrics

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Study on Networking and Monitoring Service Platform of Vehicle Security Detection Line SUN Zheng-liang 2011, 11(3): 27-31.  Abstract ( )   This study proposes the overall technology rotes of networking and monitoring service platform for vehicle security detection line based on WebService technology methods, aiming at resolving some serious problems existing in vehicle security detection line, such as various equipments, data sharing, standard operation, and so on. This study describes the structure design and main function of the service platform, proposes the standardized process control and process monitoring, designs some interface specifications to access of vehicle registration information of local government, and ultimately establishes a national technical standard for this area. The results are expected to conduct local governments to set up the service platform, regulate the application, service for social citizens, and improve the capability of local governments in the supervision of vehicle security detection. Related Articles | Metrics

Systems Engineering Theory and Methods

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The Impact of Automated Truck Lanes on Intercity Expressways: A Study Using Hybrid Simulator SUN Xun, MIWA Tomio, MORIKAWA Takayuki 2011, 11(3): 32-42.  Abstract ( )   Automated Truck Lanes (ATL) is a future technology for alleviating high proportion of truck usage. This paper proposes a hybrid microscopic-mesoscopic traffic simulator that can be used to precisely estimate the changes in traffic flows that would result from introduction of ATL on large-scale road networks. An integration framework is designed to ensure consistency of route choice and synchronization between mesoscopic and microscopic simulators. Microscopic car-following and lane-changing models are extended to reflect detailed interactions between cars and trucks. Three cases are simulated to evaluate the impact of ATL on traffic flows, proportion of trucks, travel time, and performance in total travel time saving. Finally, an analysis of safety and of the effect of road incidents on travel time are also conducted using the hybrid simulator. Simulation results indicate that ATL can change traffic volumes not only on the expressway itself (New Tomei-Meishin Expressway) but also on the other expressways in the network, leading to shorter travel times and improved safety. For a more precise evaluation, the ATL system should be analyzed as part of a large-scale road network. Related Articles | Metrics

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Highest Reliability-based Optimum Maintenance Scheduling Model for Traction Substations in Railways CHEN Shao-kuan, JIA Shun-ping, DU Peng, FENG Jia, MAO Bao-hua 2011, 11(3): 43-49.  Abstract ( )   Optimum maintenance scheduling for traction substations guarantees reliable and efficient operation of electrical railways. Reliability-based optimum scheduling models are respectively proposed through the analysis of the structure and maintenance cost of individual components in traction substations in this study. An individual components-based heuristic algorithm for solving the proposed models is developed considering the structural complexity of tractions substations. Furthermore, a reliability evaluation-based co-ordination method is devised for optimum scheduling of traction substations. Case studies from field data are implemented to verify the validity and practicability of the proposed methods by their solutions. Related Articles | Metrics

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Forecasting Baltic Panamax Index with Support Vector Machine YANG Zhong-zhen, JIN Lian-jie, WANG Ming-hua 2011, 11(3): 50-57.  Abstract ( )   This paper develops a model to forecast the freight index through studying the internal mechanism and the external influence factors. The model can provide a powerful tool for the operators and investors to understand the market trend and avoid the price risk. By taking the freight index of Panamax bulk carriers as subject, firstly, in order to eliminate the impact of random incidents in dry bulk market, wavelet transform is adopted to de-noise the Baltic Panamax Index (BPI). Then, the wavelet transform and Support Vector Machine (SVM) combined model to predict BPI is established. The inputs of the model are the values of the five prior consecutive monthly BPI, and the output is the sixth monthly BPI. The model and the forecasted results are obtained through SVM training. Finally, the numerical analysis shows that the wavelet transform and SVM combined model has higher accuracy and can be used to predict the trend of the freight rates of the Panamax bulk carriers. Related Articles | Metrics

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Optimization of Quay Crane Dynamic Scheduling Based on Berth Schedules in Container Terminal JIN Zhi-hong, LI Na 2011, 11(3): 58-64.  Abstract ( )   The quay crane dynamic scheduling problem based on berth schedules in container terminal involves the allocation of limited quay crane resources and the scheduling of loading and unloading tasks on each ship, with its berth time and location known, in order to reduce the total time of all the ships arriving at the terminal in the planning horizon. Under the real constraints of non-crossing of quay cranes and the sequence requires among tasks, the non-linear mathematical planning model is set up. A genetic algorithm is proposed according to the characteristics of the problem, and the chromosome representation is structured on the sequence of tasks. The model and the algorithm are proved effectiveness via the comparisons of scheduling results with literature on a single ship, the comparisons of scheduling results between multi-ships and single ship, and the simulation of quay crane dynamic scheduling among multi-ships. Related Articles | Metrics

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Optimization Model for Resorting Capacity of Marshalling Station under Considering Proportion of Direct Trains TIAN Ya-ming, LIN Bo-liang, WANG Zhi-mei 2011, 11(3): 65-70.  Abstract ( )   The optimization for resorting capacity of marshalling station should refer to actual needs. After the completion of strategic loading station, the proportion of direct trains will increase, and the amount of reclassification in the network will decrease, affecting the capacity needs of each station. So this paper constructs an optimization model for resorting capacity of marshalling station under considering proportion of direct trains, calculates the proportion of direct trains, the traffic organization program, and the capacity of marshalling station to relate to each other, sets an accurate variable to describe resorting capacity of marshalling station, and then successfully solves the problem by mathematical software LINGO. The result shows that the higher proportion of direct trains cloes not mean the better, there is an optimum value to minimize the total cost. The optimization result of the model is precise and effective, and the desired effect is achieved. Related Articles | Metrics

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Short-Term Traffic Flow Combination Forecast by Co-integration Theory LAN Jin-hui, GUO Min, LU Hai-feng, XIAO Xiang 2011, 11(3): 71-75.  Abstract ( )   Short-term traffic flow prediction is a priority issue of intelligent transportation system. The accuracy of the prediction results directly affects the traffic control and management. Therefore, it is the key technology for the advanced traffic management information system. This paper briefly describes the concept of co-integration and error correction model, and then verifies the validity of the combination of traffic flow forecasting model using the co-integration of series. It also improves the stability of the combination forecasting model through the error correction model. The historical and real-time traffic flow data, collected form the Second Ring Road of Beijing, are used to verify the model. The results indicate that the combination model based on the co-integration and error correction model meets the actual traffic flow characteristics well and obtains a better prediction result. Related Articles | Metrics

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Evacuation Routes Optimization with Effects of Traffic Light at Intersections MU Hai-bo, YU Jian-ning, LIU Lin-zhong 2011, 11(3): 76-82.  Abstract ( )   Intersection is the fundamental unit of urban traffic network. Thus the delay caused by traffic light at intersection is non-ignorable when regarding the evacuation routes. Because an intersection with traffic light consists of a repeated sequence of time windows with designated duration, different starting time of evacuation corresponds to different intersection delay and evacuation routes. Considering the intersection delay and capacity, superior evacuation routes and the flow assigned to each route are obtained by adopting the compound labeling algorithm to find the minimum cost flow of the traffic network. In the numerical example, evacuation routes with different starting time are compared, which indicates that the proposed method can get a good result with consideration of evacuation time and route optimization. Related Articles | Metrics

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Simulation Research on the Traction Energy Consumption of High-Speed Trains in China ZHANG Xing-chen, FENG Xue-song, MAO Bao-hua, JIA Shun-ping, FENG Xu-jie 2011, 11(3): 83-86.  Abstract ( )   According to a computer-aided simulation method, this study analyzes the effect of the maximum target speed, transport distance between stops and utilization ratio of seat-kilometers on the energy consumption per unit passenger transport by the CRH-3 electrical multiple unit operating on a high-speed rail line in China. It is found that the increase of the traction energy consumption per unit passenger transport with the improvement of the maximum target speed is much faster than the increase of the maximum target speed. Moreover, as for a maximum target speed, the traction energy consumption per unit passenger transport increases with the decrease of the transport distance between stops and such increase accelerates with the increase of the maximum target speed. Furthermore, the traction energy consumption per unit passenger transport decreases obviously with the increase of the utilization ratio of the seat-kilometers of the train, especially when the utilization ratio is smaller than 50%. Based on the study results, some suggestions are proposed from the perspective of energy-saving. Related Articles | Metrics

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Research of Passenger Flow Assignment Based on Passenger Train Plan NIE Lei, HU Xiao-feng, TONG Lu, FU Hui-ling 2011, 11(3): 87-92.  Abstract ( )   The assignment based on passenger train plan is an important method to evaluate the train plan. This paper summarizes the features of railway passenger assignment and further develops a passenger train service network. Considering the passenger choice behavior, the paper proposes a calculation method of the network impedance, which can reduce the influence of different travel distance passengers’ choice behavior. With the characteristics of railway passenger transport, the proposed model takes transfer time, OD passenger flow, and train capacity as constraints. For model solution, a penalty function is used to transform a multi-constrain model to a standard UE model, and an improved algorithm based on F-W is used, which overcomes the shortcoming of standard F-W algorithm without the record of OD path information. In the final section, a case study proves the feasibility and effectiveness of the proposed method. Related Articles | Metrics

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Multi-Class Network Equilibrium Based on the Variable PCE of Mixed Traffic LIANG Chao, FAN Bing-quan, CHENG Jian-qiang 2011, 11(3): 93-99.  Abstract ( )   Mixed traffic flow, consisting of cars, trucks and other like, is one of the major characteristics of China’s road traffic. The complex composition and significant disturbance have received extensive attention from researchers. The paper develops a multi-class network equilibrium model. In which, travel time and road prices are separately given for different classes of users, and there is no interaction among them. The volume delay functions based on the variable PCE of mixed traffic are nonlinear, non-smooth, and asymmetric. The problem is formulated as a nonlinear variational inequality model, and the algorithm-the method of successive averages (MSA), is used to solve the problem. Finally the algorithm is implemented in the EMME/3 transportation planning software, and applied to the actual highway network, and the conversion coefficient of linear and nonlinear the transport assignment results are compared. Studies have shown that traffic assignment with non-linear conversion coefficient is more realistic of the traffic flow distribution. Related Articles | Metrics

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Optimization on the Occupation Order for Trains on Tracks of the Railway Station ZHANG Jia-min, HAN Bao-ming 2011, 11(3): 100-107.  Abstract ( )   All of the effects resulting from the interaction between the fixed railway infrastructure and its mobile counterpart are embodied on the time dimension, but it’s hard to express the dynamic characteristics of the train’s acceleration/deceleration and the approximate constant speed with the precise data. Based on these, according to the topology of the station tracks and the passenger demand of high speed railway, combined with the dynamic characteristics of the train run, this paper puts forward the basic research thinking for the application of the Fuzzy Timing High-level Petri Nets (FTHNs)-Conflict Graph double model to research on the computation & evaluation of the high speed railway station. It defines the train service-demand intention set (t @ s-TSDIS) in a period, aiming at the minimization of the station tracks’ occupation time for the completion of the defined t @ s-TSDIS, and synthetically applies the FTHNs, Max Plus, improved simulated annealing for the optimization of the station tracks’ occupation order. Related Articles | Metrics

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Queuing Time Calculation Model for Bus Stop with Two Berths Based on Operation Reliability YANG Jing, ZHANG Rui, WU Hai-yan, ZHANG Zhe-ning, MAO Bao-hua 2011, 11(3): 108-112.  Abstract ( )   As the basic infrastruction of bus transit, bus stops have got a lot of attention from the traffic engineers for efficiency improvement. This paper puts forward the definition and formation process of out-of-berth queuing time (OOBQT) based on bus microscopic behavior at bus stop. Then, according to the bus operation reliability, OOBQT calculation model for bus stop with two berths is constructed. The expectation and possibility of OOBQT are proposed based on the bus arriving and dwelling distribution. Through numerical computation examples, it is proved that with the increase of the random degree of dwelling time, the expectation and possibility of OOBQT increase, especially when the Erlang distribution shape parameter k below 10. Related Articles | Metrics

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Dynamic Optimal Path Algorithm in Vehicle Navigation System WANG Peng-fei, MA Shou-feng, JIA Ning 2011, 11(3): 113-118.  Abstract ( )   Most of the optimal path search algorithms in the current vehicle navigation system can only satisfy the static traffic environment. When traffic environment and the traveler position changes, the data will be recalculated and the overall optimal path will be searched again, the process is very slow. On the basis of the LPA algorithm, it first changes the problem of unfixed position of traveler and fixed destination into a fixed origin and destination problem. On the other hand, with the idea of incremental search it updates its heuristics between search episodes. At last, a dynamic optimal path search algorithm is proposed for in-vehicle route guidance system. Then the algorithm is developed on Windows Mobile platform, the analytical results demonstrate that when traffic environment and the traveler position changes, the algorithm can quickly search for the optimal path. The cost of search time is much smaller than the static shortest path-finding algorithm. Experiments and actual results show that this algorithm is of great referential value and applicable significance. Related Articles | Metrics

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Railway Station Operation Standard Time Assessment Method Based on Informatization CHEN Jun-hua, ZHANG Xing-cheng, XU Bin, HUANG Xiao-bo 2011, 11(3): 119-123.  Abstract ( )   Railway station operation standard time assessment is an important work. It can find weaknesses of existing equipment and work organizational, and then expand to take appropriate measures to achieve the potential to improve the efficiency of railway station. However, traditional manual method of assessment has the following shortcomings: heavy workload, long cycle, low precision. This paper presents railway data-based automated standard time assessment method, and solves some key issues such as original data acquisition, multi-source data processing, and so on. The paper further sets up an automated search standard system, and takes the railway line Da Tong-Zhun Ge Er as an example. The case study results show that the new method is simple, operable, high precision, and have significance to promote. Related Articles | Metrics

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Evaluation Method for Adjustment Scheme of Bus Lines in Beijing WANG Zhen-bao, CHEN Yan-yan, DUAN Wei-jing 2011, 11(3): 124-130.  Abstract ( )   The bus network should be changed to accommodate the equilibrium of supply-demand when the subway line starts operating. This paper presents an evaluation method for the adjustment scheme of bus lines, and puts forward an evaluation index system based on the objective of the equilibrium of supply-demand for the passengers, the equilibrium of supply-demand for the public transport facility, the rationality of geometry for the bus lines and the co-harmony among the bus lines. Whether or not the adjustment scheme of bus lines will be proposed to implement is decided by analyzing the result of comprehensive evaluation, such as fuzzy comprehensive evaluation (FCE). A case study about deleting a bus line in Beijing is provided to illustrate the proposed procedure, and the operation situation after implementing the scheme is analyzed. The method and the evaluation conclusions will be useful for decision-making. Related Articles | Metrics

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The Method of Data Processing for Train Characteristic Curve Based on Bezier Function TANG Jin-jin, ZHOU Lei-shan, TONG Lu，RAN Feng 2011, 11(3): 131-137.  Abstract ( )   In the filed of train movement calculation, the interpolation method is commonly used to calculate the data of train characteristic curve with rear new approaches proposed. By comparing the Bezier curve and the train characteristic curve, it can be found that Bezier curve can well describe the train characteristic. The paper presents a calculating method based on human-computer interaction. The function of Bezier curve is the fitting function of the train characteristic curve. The calculating speed and accuracy are significantly improved with the proposed method. The curves of train-set CRH3 are fitted, and a satisfactory result is obtained in the case study. Related Articles | Metrics

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Finding Critical Traffic Control Locations for Emergency Evacuation ZHANG Xiong-fei, SHI Qi-xin, HE Rachel, BAN Jeff 2011, 11(3): 138-143.  Abstract ( )   This paper aims to explore mass evacuation problem of large-scale road network in the event of natural or man-made disasters, such as earthquakes and hurricanes. Under emergency evacuation, traffic control devices and personnel are limited. It is impossible to control all the traffic nodes on the network. Therefore, it is crucial to find the most critical traffic control locations or intersections to deploy control devices or arrange manual evacuation guidance, so that the best system performance can be achieved. In order to answer the urgent theoretical and practical deployment problems, this study proposes a mixed integer nonlinear programming (MINLP) model, which aims to identify the most crucial intersections, and simultaneously, the optimal traffic control strategies at those locations, to minimize the total system costs. Numerical example shows that the model performs reasonably well, and with the appropriate set of critical intersections controlled, the resulting system performance does approach the system optimal state with all intersections under control. Related Articles | Metrics

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An Integrated Control Method with Signal Priority and Holding Strategy for BRT System WANG Ning, ZHANG Li-guo, CHEN Yang-zhou 2011, 11(3): 144-150.  Abstract ( )   Real-time scheduling and signal priority strategies play a critical role in improving the service quality of Bus Rapid Transit (BRT) system. The bus start-stop loss, public passengers’ delay and general social vehicles’ delay are essential factors that should be considered for signal priority control. Based on the optimal control of the the BRT Line 1 of Beijing city (South Axis), the paper proposes an integrated control method with modeling the total delay at intersections. The method is based on the signal priority (early green and green extension) and holding strategy. Because of the proposed method, the bus priority is ensured, and the bus delay and negative impact on the general traffic are reduced. The influences from passenger boarding and alighting processes and other factors on the scheduling system are also reduced to some extent. Several traffic scenarios are also used to verify the effectiveness of the presented method. Related Articles | Metrics

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DEA and TOPSIS Combination Model for the Construction Scheduling of Urban Road Projects MENG Meng, SHAO Chun-fu, DONG Chun-jiao, HU Chao-fan, LIU Xin-hua 2011, 11(3): 151-155.  Abstract ( )   The construction scheduling of urban road projects is a typical multiple stage and multiple attribute decision making problem. To improve the availability of the urban road planning and construction, a model with multiple stage and multiple attribute is proposed, which is based on the DEA and TOPSIS. The DEA method is used to calculate each DMU’s relative efficiency, then the TOPSIS method is used to rank the relative efficiency, and the urban road construction sequence is obtained accordingly. In this model, the advantages of the DEA’s superiority of evaluating with multiple inputs and outputs indicators and the TOPSIS’s systematicness and comprehensiveness are utilized. And the shortcoming of the DEA’s failure to rank all projects is avoided, which provides a new approach to this problem. Finally, an example is presented to illustrate the effectiveness of the proposed method. Related Articles | Metrics

Cases Analysis

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Comparative Analysis on Weighted Network Structure of Air Passenger Flow of China and US DANG Ya-ru, LI Wen-jing 2011, 11(3): 156-162.  Abstract ( )   From the perspective of network scale, edge-weight distribution, node-strength distribution, and network resilience, comparative analysis is made on the structure of air passenger flow weighted networks of China and the US from the year 2003 to 2008, using complex network theory and visualization. Results show that Chinese network has a strong capacity of air passenger traffic and great development potential, though there is a large difference in the network scale between China and the US. Both edge-weight distribution and node-strength distribution of the domestic networks of China and the US obey the power law, showing stability under random attacks and frangibility under coordinated attacks. The comparative analysis on network resilience of China and the US demonstrates structural stability of multi-hub network is much stronger than that of “Tripod Ding Pattern” network. Therefore the construction and management of hubs in China should be strengthened. Related Articles | Metrics

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Analysis on Passenger Trip Mode split of Beijing Subway ZHENG Yi 2011, 11(3): 163-168.  Abstract ( )   In recent years, subway as a kind of urban public transportation has become more and more important in big cities, so it is particularly important to analyze subway passenger trip mode split. We get the transit choosing discipline and spatial distribution of passengers in the subway transit system via passenger surveys of Line 5 of Beijing Subway. The study conclusions show that the walking is the most mainly transfer mode because of passenger mainly from the direct service area; the regular bus is the second transfer mode; the people who chooses car trip always transfer to P+R transfer mode when they get to the station by car. Based on the data analysis, this paper proposes that the planning and design of subway transit system should be based on the attract range and the regional characteristics of the station, in order to achieve the close transfer between ground bus, bicycle, walking, taxis, private cars and the subway. Related Articles | Metrics

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Analysis on Subsidies Modes of Capital Asset Replacement in Urban Rail System TIAN Zhen-qing 2011, 11(3): 169-175.  Abstract ( )   A reasonable and efficient subsidies mode and management mechanism, which ensures the operational safety of rail systems and helps decreasing the cost of rail transportation, is one of the urgent problems in the development of urban rail transit system. This paper compares the characteristics and applicability of the four typical subsidies modes, including cost-plus contract, fixed price contract, incentive contract and commercial franchise contract, by presenting their subsidies models and exploring the corresponding practical applications in typical urban rail transit. It aims to provide instructive suggestions to the development of capital asset replacement management in Chinese urban rail transit systems. Related Articles | Metrics

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Comparative Study of MOBILE and COPERT Emission Models Based on PEMS CHENG Ying, YU Lei, WANG Hong-tu, HAO Yan-zhao, SONG Guo-hua 2011, 11(3): 176-181.  Abstract ( )   In order to investigate macro-scale vehicle emission models suitable for China, this paper systematic introduces the principles, characteristics and applications of the MOBILE and COPERT models at first, then describes the methods of data collecting and dealing of PEMS equipment, and finally modifies the models’ input parameters based on the data collected by using PEMS equipment. The emission factors for different road types from the two models are compared with the measurements from real-world tests. The results show that, during the whole vehicle driving cycle and on all classified roads, the predicted emission factors of NOx, HC and CO from the COPERT Model are closer to the measured values than those from the MOBILE Model. Specifically the errors of the former are 19.2%, 40.8% and 22.0% less than the errors of the latter during the whole vehicle driving cycle. In the end, it comes into a conclusion that COPERT model is more suitable for predicting vehicle emission in China than MOBILE model. Related Articles | Metrics

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Study on the Capacity Expansion and Upgrading Plan of Yulin Railway Hub LU Da-fei 2011, 11(3): 182-186.  Abstract ( )   In recent years, many railway hubs need to face the problem of capacity expansion and upgrading plan. Planning method of railway hub’s capacity expansion is explored in this paper. Based on the analysis of Yulin railway hub location and status, we point out the main issues of the hub that need to be solved. With the consideration of forecasting volume of railway freight and passenger，the general arrangement plan of Yulin railway hub is proposed．As the key, we propose the synthetic evaluation method and compares the planning schemes from six aspects including project quantities, capacity of line and throat, transport organization, construction transition, interferes to the transportation, cohesion of planning project, and costs. Related Articles | Metrics