Loading...

Archive

    For Selected: Toggle Thumbnails
    Decision-making Forum
    Pricing Strategy of Port Competitive Service Based on Market Regulation
    DONG Gang
    2019, 19(2): 1-6. 
    Abstract ( )   PDF (3453KB) ( )  

    In order to play the decisive role of market mechanism in port resources allocation, the tariffs of port competitive services in China are transforming government unified and guided pricing into market regulation. Therefore, port operator should optimize pricing strategy of competitive service to maximize its profit under market regulation mechanism. Based on the key factors, this paper constructs a pricing strategy model of port competitive services, comparing the profit differences among Bertrand competitive pricing and price-matching, as well as the mixed pricing strategies. The sensitivity analysis of multi-factor is also carried out. The results show that the strategy profile (price-matching, price-matching) is Nash equilibrium of port competitive service pricing game. The optimal profit of port competitive service is not only positively related to shipper's pay willingness and port design capacity, but also subjected to the volatility of price elasticity, as well as multiple relationships between them, providing the decision-making reference for port operator to choose pricing strategies.

    References | Related Articles | Metrics
    Forum about Comprehensive Transportation System
    Regionalization of China's Transportation Energy Consumption Based on Full-order-constrained Complete Linkage Partitioning
    WU Xu, DU Yi, JIA Chuan-jun
    2019, 19(2): 7-13. 
    Abstract ( )   PDF (4861KB) ( )  

    The regionalization of the nationwide is the basis of studying the energy consumption of transportation with large scope and regional characteristics. Firstly, three categories of transportation energy consumption index are set up, including transportation industry indicators, energy consumption of transportation indicators, and social and economic indicators. The adjacency matrix is built based on the attribute- based distance and adjacent relationship between provinces and municipalities. Then the spatially contiguous network of national transportation energy consumption is generated. According to the adjacent relationship and the full- orderconstrained complete linkage method, the minimum adjacent generation tree of national transportation energy consumption area is obtained. The minimum tree is truncated with the goal of maximum national homogeneity, five transportation energy consumption regions are divided. The characteristics of transportation energy consumption in each region are analyzed, and preliminary policy recommendations are put forward.

    References | Related Articles | Metrics
    Invulnerability Simulation in Urban Agglomeration Passenger Traffic Network under Targeted Attacks
    LI Cheng-bing, ZHANG Shuai, YANG Zhi-cheng, LIU Zhen-yu
    2019, 19(2): 14-21. 
    Abstract ( )   PDF (4123KB) ( )  

    To improve the traffic system' s ability to fight targeted destruction in urban agglomeration, composite traffic network is used to research urban agglomeration passenger traffic network' s invulnerability. First, the model of urban agglomeration passenger composite traffic network is established and weighted with practical passenger flow. Secondly, the model of optimal allotment base on spare capacity is improved, then the model of composite traffic network cascading invulnerability is established. Thirdly, between network efficiency and relative scale of weighted most large connected subgraph are put forward to evaluate network' s invulnerability. Finally, using targeted attack strategy, H-B-E urban agglomeration is used to simulate as example. The results show that: under targeted attacks, only two attacks can reduce the invulnerability of urban agglomeration passenger traffic network by about 90%; under certain passenger demand, there is a threshold for the overload capability adjustment parameter; if the station construction investment exceeds this value, it will cause unnecessary waste.

    References | Related Articles | Metrics
    Influence Model of Social Network Traffic Information on the Travel Mode Choice Behavior
    FU Zhi-yan, ZHAO Han-lin, CHEN Jian, YU Min
    2019, 19(2): 22-29. 
    Abstract ( )   PDF (3719KB) ( )  

    This study mainly deals with the problem of quantitatively measuring the influence of social network traffic information on travel mode choice behavior. According to the Technology Acceptance Model, 7 latent variables, including perceived usefulness, perceived usability, perceived risk etc., are proposed as the perceived variables of travelers on social network traffic information. A hybrid discrete travel mode choice model is constructed by combining personal attribute variables and travel plan variables with social network traffic information. The empirical analysis is conducted using the questionnaire of Chongqing city in China. The results from the hybrid model show an improvement of 0.171 in goodness of fit. The variable of perceived risk shows negative effect on the travel mode choice, while the other variables show positive effect. The three variables of perceived usefulness, subjective norm, and perceived trust show the most significant effect on the selection, of which the coefficients are 0.757, 0.646 and 0.502 respectively.

    References | Related Articles | Metrics
    The Impact Mechanism of Cross-border Traffic Accessibility on Port Economy of Border Cities
    LI Jie-mei, WU Hao, LIU Chen, HAO Jing-jing
    2019, 19(2): 30-36. 
    Abstract ( )   PDF (2584KB) ( )  

    In order to obtain the impact mechanism of the cross- border transportation accessibility on port economy, a cross- border traffic accessibility evaluation model and an analytical framework of port economic development level are constructed. Then the gravitational model is established to analyze the impact mechanism. The results show that: ① Both the cross- border traffic accessibility and port economy show significant spatial differentiation characteristics of“East Strong West Weak”. The development level of traffic accessibility and port economy of border cities shows a trend of increase year by year with the implementation of“The Belt and Road Initiative”. The promotion effect in the western region is more significant, and the dominant position of the northeast region is declining. ② The traffic accessibility of border cities has a significant positive impact on the port economic development, but after the traffic accessibility reaches a higher level, its promotion effect gradually weakens. ③ The international trade facilitation index is also an important factor affecting the development of port economic, and its impact is increasing year by year.

    References | Related Articles | Metrics
    A Competitiveness Analysis of International Container Transport Based on Value of Goods
    ZENG Wei, MAO Bao-hua
    2019, 19(2): 37-45. 
    Abstract ( )   PDF (5599KB) ( )  

    There is a competitive relationship between international container trains and traditional sea- land multimodal transportation and air transport. Based on the analysis of the relationship between competitiveness and cargo value, this paper builds a relative competitiveness model of international container trains based on the theory of comparative advantage, and then studies the types of goods transported by international container trains under different cargo value characteristics. This paper analyzes the impact of government subsidies, railway transportation rates, and train transportation time on the competitiveness of international container trains. The results show that the goods that are suitable for transport in international container trains are mainly mediumsensitive goods. The competitiveness of international container trains increases with the value of goods, and as the value of goods increases, the affordability of goods to freight increases, and the requirements for transport service levels increase. The relative competitiveness of international container trains increases with the increase of train subsidies. The government should provide subsidies to provide policy support for market development.

    References | Related Articles | Metrics
    Intelligent Transportation System and Information Technology
    Function Demand of Urban Rail Transit Emergency Command System Based on Scenario Analysis
    JIA Wen-zheng, SONG Xiao-min, LIAO Li-ming, FENG Xu-jie
    2019, 19(2): 46-51. 
    Abstract ( )   PDF (4180KB) ( )  

    Operational emergencies may cause interference to train operation and passenger transport organization of urban rail transit, and an emergency command system is needed for comprehensive scheduling and emergency response. Emergencies are uncertain, so function demand analysis is one of the most important phases in emergency command system development, and the main task is to describe system behaviors unambiguously, consistently and completely. The scenario construction, tasks and function demand are described using scenario analysis method, and the general strategy to generate functional requirements is proposed. Taking a signal system fault as an example, the function demand and data support are analyzed. The results show that scenario analysis is effective to capture the function demand of emergency command system and can better solve the uncertainty and completeness.

    References | Related Articles | Metrics
    Collaborative Control Method of Tidal Lane Clearing and Downstream Intersection Signals
    SHANG Chun-lin, LIU Xiao-ming, SHEN Hui, TIAN Yu-lin, LI Li-li, TANG Shao-hu
    2019, 19(2): 52-59. 
    Abstract ( )   PDF (4314KB) ( )  

    Nowadays, the clearance of the tidal lane becomes one of the keys to improving the control efficiency of the tidal lane. Based on the theory of gather-disperse wave, this paper analyzes the running state of the vehicle under the condition of direct green light inflow and left turn green light inflow, and builds a relationship model between lane indicator switching time, downstream intersection signal control and corresponding lane clearing time. And then, a combined optimization model for designing the lane clearing time and the delay of the downstream intersection is designed. Finally, the genetic algorithm is used to solve the objective function optimally, and obtained the optimal combination control scheme. It is found by simulation that different lane indicator change time and downstream signal priority strategy would increase the lane clearing rate, but it also increases the delay of the downstream intersections, and the integrated optimization model can be used to find out the best control strategy to balance the needs of both.

    References | Related Articles | Metrics
    Road Detection Based on MS-RG Hybrid Image Segmentation Model
    LIU Bu-shi, LV Yong-bo, LV Wan-jun, LI Jing, OUYANG Qi
    2019, 19(2): 60-65. 
    Abstract ( )   PDF (3730KB) ( )  

    Due to the diversity of its structure, the complexity of texture changes and the instability of natural exposure, road scenes based on road segmentation mostly have information redundancy, and there are quality problems such as boundary loss and blur. In this paper, we first used the Meanshift algorithm on the road image to find the local optimum by the trapezoidal rise of the probability density in the space, and search for the pixels with the same modulus and then get together to form the super pixel block. Then, the clustering super- pixel block obtained by the Meanshift algorithm was used to perform a variety of sub-point region growth, standardized the growth rule, overcome the defect that the closed boundary cannot be obtained, improve the segmentation effect of the road image. The experimental results show that the proposed method has strong applicability, and it can effectively improve the segmentation accuracy and real-time performance compared with the traditional method, and can accurately identify the road information in the image to ensure that the vehicle can travel on the travelable area.

    References | Related Articles | Metrics
    Analyzing Methods of Vehicle' Travel Using Plate Recognition Data
    LONG Xiao-qiang, SU Yue-jiang, YU Chang, WU De-xing
    2019, 19(2): 66-72. 
    Abstract ( )   PDF (4405KB) ( )  

    Vehicle travel is the basic component of urban road traffic. There is an urgent need for urban traffic manager to obtain the trip information on urban road network, and make a better understanding of vehicles' travel characteristics. In this paper, an analysis framework based on plate recognition data is proposed. Firstly, the individual trip information of all vehicles on urban road network is identified and the trip information of all vehicles are extracted. And then vehicles' travel characteristics are obtained at the individual and aggregate level. A methodology is proposed for recognizing vehicles' residence and workplace based on trip information and statistical feature. K-means ++ algorithm is applied to cluster and classify the nonlocal vehicles. In case study, focused on the vehicles of Guangzhou City, the analysis of vehicles travel are conducted. The effectiveness of the proposed method is proved by the case study results. The information mined through the method is of great significant for urban road traffic management.

    References | Related Articles | Metrics
    Cellular Automaton Model Considering Velocity of the Front and Rear Vehicles and Deceleration Values
    XIA Yun-da, ZHAO Yang
    2019, 19(2): 73-79. 
    Abstract ( )   PDF (4111KB) ( )  

    Three- phase traffic theory and fundamental diagram approach propose own different interpretations for the phase transition from free flow to congested flow and the controversy between two sides has not been solved yet. Based on typical slow-start model rules, the paper proposes a cellular automaton model of traffic flow considering velocity of the front and rear vehicles and deceleration values to investigate the phase transition from free flow to congested flow. The deceleration value of the new slow-start model is connected with velocity of the front vehicle and the two deceleration values set correspond to slow deceleration and rapid deceleration. The simulation results of the new slow- start model show that the traffic may be in free flow or congested flow corresponding to the same density;small jams can exist steadily in the road system and have the trend of synchronization;under the condition that a lot of vehicles that do not consider the comfortable driving and tend to decelerate rapidly exist on the road, pinch effect proposed by three-phase traffic theory is irrational and free flow can be transited into jams directly.

    References | Related Articles | Metrics
    GBDT Method Based on Prediction Model of Daily Dimension Traffic Index
    WENG Jian-cheng, FU Yu, LIN Peng-fei, WANG Jing-jing, MAO Li-zeng, LI Dong-yue
    2019, 19(2): 80-85. 
    Abstract ( )   PDF (3677KB) ( )  

    Monitoring and forecasting of urban traffic operation is an important task to grasp the characteristics of traffic operation changes and formulate strategies to alleviate traffic congestion. The forecasting results can provide effective road information for the public, and also provide support for the formulation of policy measures and the evaluation of the effect. Different from the traditional short-term traffic forecasting, the forecasting model proposed in this paper is not for the operation state prediction of adjacent periods, but for the long-span, for the daily traffic operation state prediction. This paper constructs a multidimensional factors set including time period, weather, holidays, vehicle restriction, large events and so on; builds a data training set based on long- term historical traffic index, and proposes a daily road network condition prediction model based on gradient boosting decision tree; validates the model by using the optimal model. The results show that the prediction accuracy of the model can reach more than 90% . The comparative analysis of the regression model also shows that the model presented in this paper performs best in all scoring items, indicating that it is more suitable for regression analysis with large samples and multiple factors. The daily prediction model proposed in this paper has important application value in improving the quality of urban road network operation and alleviating traffic congestion.

    References | Related Articles | Metrics
    Systems Engineering Theory and Methods
    Measurement of Space-time Accessibility to Service Facilities Considering Travel Time Uncertainty
    FU Xiao, LI Meng-yao, LU Xin, CAI Xian-hua
    2019, 19(2): 86-93. 
    Abstract ( )   PDF (5458KB) ( )  

    In congested multi-modal transport network in China, the uncertainty of individuals’travel time is significant. The travel time uncertainty significantly affects individuals’travel choice behavior. To conduct some important activities such as seeking medical service, individuals normally have high expectations of travel time reliability. This paper takes the space-time accessibility of general hospitals in Xuanwu District of Nanjing as an example. The space- time accessibility of service facilities in multi- modal transport networks is intensively explored by extending the gravity model and the travel time budget model. A new method is proposed for measuring the space- time accessibility with consideration of travel time uncertainty. Individuals’risk decisionmaking behavior is analyzed regarding different transport modes. The results provide effective bases and evaluation indicators for urban multi-modal transport development and land use planning. The results show that using different transport modes, there are significant differences among the space-time accessibilities to service facilities under various travel time reliability constraints.

    References | Related Articles | Metrics
    Optimizing a Bus Bridging Strategy Considering Efficiency and Equity
    ZHENG Yu-jing, GU Wei, JI Yu-xiong, ZHANG Hong-jun
    2019, 19(2): 94-101. 
    Abstract ( )   PDF (4197KB) ( )  

    Efficient bus bridging strategy during metro disruptions is needed to evacuate passengers to reduce the social and economic loss. We propose a two-stage model to assign each bus a bridging plan that lists the stations to visit in sequence since it is dispatched from the depot. Stage I is to minimize the evacuation time from the view of managers, while stage II is to reduce the passenger delay from the view of passengers. Two objectives, reflecting efficiency and equity respectively, are considered in stage II. Since the deficiency of existing commercial software in solving stage II, a modified Tabu Search (TS) algorithm is developed to improve the computation speed. Finally, a case study is presented to demonstrate the practicability of the algorithm and the model. Also, we discuss the trade-off between efficiency and equity by comparing the results: considering efficiency could lead to polarized results, while considering equity provides a more balanced service at the cost of increasing the delay for the whole system.

    References | Related Articles | Metrics
    Tandem Scheduling Algorithm on Opposition-learning
    WANG Min, CHEN Feng, ZHANG Lei-shi
    2019, 19(2): 102-107. 
    Abstract ( )   PDF (3622KB) ( )  

    In order to avoid the tandem traffic problem, a real-time vehicle tandem scheduling algorithm with different station intervals on multiple routes is studied. Based on the data analysis and prediction of AVL data, an Opposition-learning Clonal Selection Algorithm (OCSA) with opposition-learning ability is proposed,the scheduling sequence is used to avoiding tandem traffic and guide vehicle scheduling. In the algorithm, a reverse antibody library is designed, which stores the information of several inferior antibodies during the population iteration. The location information of the inferior genes is used to guide the reverse learning, in order to pull them out of the local optimal region quickly. The opposition- learning process can rapidly improve the diversity of antibodies, so that the algorithm has a strong global optimization ability in a short time, and the scaling factor of local learning can be dynamically adjusted with the iterative process to improve the accuracy of the algorithm. The experimental results show that the scheduling sequence obtained by OCSA algorithm has better adaptability than the classical scheduling algorithm, and the scheduling sequence obtained by OCSA algorithm can effectively reduce the tandem traffic problem in real-time.

    References | Related Articles | Metrics
    Parking Path of Harbour Bus Platform Based on Automatic Tracking
    MA Qing-lu, FENG Min, QIAO Ya
    2019, 19(2): 108-115. 
    Abstract ( )   PDF (5105KB) ( )  

    Because most of the existing buses use free parking mode, resulting in delays in vehicle departure, low utilization of parking space and passenger safety problems. In this paper, based on the existing "one- button" automatic bus stopping system, aiming at optimizing the running trajectory of the automatic bus stopping, threespline interpolation, Atan and Sigmoid functions are used to simulate and analyze the stopping trajectory of the harbor-type platform bus. The results of nonlinear constrained optimization show that the continuous curvature can be obtained by using the three methods, which can satisfy the bus stop collision constraints and the harbor-type platform parking requirements, and the bus approach trajectory can be generated in real time. Compared with the harbor- type platform parking curve, The average potential difference of the Atan curve is 1.01, which is much smaller than the average potential difference of cubic spline interpolation and Sigmoid curve, which are 10.21 and 5.96 respectively. Therefore, the analysis of the trajectory results shows that the bus stopping based on the Tan trajectory curve is more convenient for passengers to ride, has the characteristics of real-time, high reliability, and reduces the inbound outbound delay.

    References | Related Articles | Metrics
    Bus Travel Time Prediction Based on Light Gradient Boosting Machine Algorithm
    WANG Fang-jie, WANG Fu-jian, WANG Yu-chen, BIAN Chi
    2019, 19(2): 116-121. 
    Abstract ( )   PDF (3261KB) ( )  

    In the operation of urban public transport networks, the travel time between stations of a bus is affected by road and environmental conditions. This paper analyzes the bus speed characteristics, road characteristics and weather characteristics during bus operation, and a feature- based LightGBM bus travel time prediction model is established. By adjusting the relevant parameters in the LightGBM algorithm, the weights of the influencing features and factors are assigned. Then the model is trained and verified by using the 24-day bus GPS data of one bus line in Tianjin, and compared with the travel time prediction model based on historical mean and Kalman filter. The comparison results show that the LightGBM model is superior to the other two models in MAE (Mean Absolute Error) and MAPE (Mean Absolute Percentage Error), indicating that the LightGBM model has good stability and application prospects in bus travel time prediction.

    References | Related Articles | Metrics
    Modeling of Train Timetable with Full-length and Short-turn Routing Considering the Time-varying Demand
    XU De-jie, GONG Liang, ZENG Jun-wei
    2019, 19(2): 122-129. 
    Abstract ( )   PDF (4443KB) ( )  

    Aimed at a radial transit lines, through considering the time- dependent characteristics of passenger demand and the circumstance that passengers are stranded on platform, a scheduling model of full-length and shortturn routing mode is established, where the objective functions are minimum passenger waiting time, running kilometer of rolling stocks, and operation time of trains, with the constraints of departure interval, scheduling mode, maximum load factor and its’equilibrium. Furthermore, a dynamic simulation model of passengers’ activities and trains’running process is constructed using the discrete event modeling method. Then, a solution method, combined with simulation method and genetic algorithm, is developed. The results show that the disequilibrium train operation scheme can better satisfy the benefits both for the passengers and the operation enterprise, and effectively reduce the crowding of morning rush- hour crush. Comparing with the equilibrium operation scheme, the optimal scheme can reduce the waiting time of passengers by 16.3%, 1 266.2 hours, while the operation cost of transit enterprise remain unchanged.

    References | Related Articles | Metrics
    An Optimization Adjustment Method for Delayed High-speed Trains Based on Multi-tree
    LI Xiao-juan, YAN Zhen-ying, HAN Bao-ming
    2019, 19(2): 130-136. 
    Abstract ( )   PDF (3651KB) ( )  

    The high- density operation mode of high- speed trains makes the train operation very sensitive to delays. Therefore, the adjustment of delayed high-speed train operation had become an important research issue. Based on characteristics of high-speed train, the operational relationship model is built. For the delay of trains, we designed 7 adjustment schemes including section acceleration, operation in advance, decreasing station stop time, decreasing overtaking, increasing overtaking, postponing according to minimum interval and operation on delay time. Operation adjustment model of delay high-speed trains to get minimum total delay time of each train at each station. And the optimization and adjustment algorithm for delay high-speed train based on staged multi-tree is designed. Finally, real train operation line of Beijing-Shanghai railway is calculated and analyzed as practical case, and effectiveness and feasibility of models and algorithm are proved.

    References | Related Articles | Metrics
    Freight Transportation Service Network Design Problem with Unbalanced Spatio-temporal Distribution of Wagon-flow
    LIU Xiao-wei, QIU Gea, NI Shao-quan, LV Miao-miao, LV Hong-xia
    2019, 19(2): 137-145. 
    Abstract ( )   PDF (4317KB) ( )  

    To provide differentiate services to heterogeneous shippers, freight transportation service network design problem is introduced to integrate car classification, train make-up and train scheduling by dynamic wagonflow organization methods. Based on basic train diagram and space-time network, an integer programming model is proposed by further considering classification and connection delay costs in the static optimization model objective. Constraints include spatio- temporal continuity between adjacent organization phases for wagon-flow, station and line time-space capacity and delivery deadline. A simulated annealing algorithm is used to solve the model, constructing an initial feasible solution by K- shortest path, designing neighborhood search strategy to adjust wagon-flow reorganization according to train capacity utilization threshold. One practical example shows that, compared to the static model, wagon-flow unbalanced spatio-temporal distribution is addressed effectively with more clearly description to wagon-flow time-space capacity occupation by decision variables, which help to coordinate wagon-flow transfer between different trains.

    References | Related Articles | Metrics
    Line Plan of Passenger-like Transport System of Railway Container
    XIA Yang, WEI Yu-guang, LAI Yi-huan, ZHANG Qi
    2019, 19(2): 146-152. 
    Abstract ( )   PDF (3523KB) ( )  

    Aiming at the line planning problem of passenger-like fast transport system of railway container, the optimization method on the basis of candidate train set is adopted, and the uniqueness of the physical path and the transport plan of container flow is determined according to the characteristics of freight transport organization. Considering the constraints of flow conservation, container transfer, transit period and operation frequency, an integer linear programming (ILP) model is built with the objective of minimizing the cost of transportation enterprises, and a simulated annealing algorithm is designed. Finally, a container transportation network is taken to carry out a case study, which verified the feasibility of the model and algorithm. The results show that compared with the existing freight transportation system, the new container system gives full play to the advantages of network transportation, and performs better in terms of train operation frequency and delivery speed, but at the same time sacrifices the train attendance rate.

    References | Related Articles | Metrics
    Influence of Lane Demarcation Patterns on Lane-changing Behavior
    DENG Jian-hua, FENG Huan-huan
    2019, 19(2): 153-159. 
    Abstract ( )   PDF (4133KB) ( )  

    In order to explore the influence of different lane demarcation patterns on lane-changing behavior, a multi-attribute lane-changing decision model based on analytic hierarchy process(AHP) is proposed to improve the lane-changing rule of symmetric two-lane cellular automata(STCA), that on the base of the analysis of the lanechanging decision mechanism and lane-changing decision attributes. Setting different lane demarcation patterns on a one-direction-three-lane way to operate the model obtains the probability of lane- changing motivation and of lane-changing success under different space occupancy rate. Results show that: the probability of lane-changing motivation is directly related to the internal state attribute of traffic flow; the success probability of lane-changing is determined by the internal state attributes of traffic flow and the lane demarcation patterns which have corresponding effects on lane-changing behavior. It is shown that this paper’s model can better interpret the traffic management and regulation implications of different lane demarcation patterns, has the ability to deal with multiple external decision attributes at the same time, and strong generality.

    References | Related Articles | Metrics
    Analysis and Modeling of Speed Choice Behavior on Low Speed-limit Road
    ZHAO Dan, WANG Jing-sheng, LI Juan, BAI Bing
    2019, 19(2): 160-165. 
    Abstract ( )   PDF (3467KB) ( )  

    It is specified that if caught speeding less than 50% on the road under the 60 km/h limit, only a warning sanction would be received, and few traffic monitors are installed, so speeding violations are common on some low- speed limit road. In this paper, a road segment located in the suburban of Beijing was selected as research object, and a stated preference (SP) survey was designed. By analyzing SP data, the factors associated with speed choice behavior is studied, and hybrid random utility-regret models are established, furthermore, the mechanism of speeding is explored. Results show that speed limit sign constrained speeding to some degree, other vehicles’average speed have stronger impact on some drivers’speed choice to the extent that traffic monitors are neglected; the factors including gender, driving experience, vehicle type and speeding penalty experience have a significant impact on speed choice behavior; drivers tend to follow regret minimization rule when measuring speeding loss and benefit to make decisions.

    References | Related Articles | Metrics
    An Analysis of Traffic Cost of Different Transport Modes Considering City Block Size
    ZHANG Ling-xuan, MONICA Menendez, ZHANG Shi-hang, SHUAI Bin
    2019, 19(2): 166-174. 
    Abstract ( )   PDF (6883KB) ( )  

    The concept of urban planning in China is gradually shifting from the closed community to the open block, so as to share interior road to the public and then optimize the road network layout. However, there is a lack of quantitative research on the specific influence of different block sizes on urban traffic. Therefore, this paper divides the traffic into two parts: traffic inside the block and outside the block, and then analyzes the impact of block size on the traffic performance (such as travel distance, travel time and number of turnings) of different transport modes. Travel time and travel fee are regarded as the generalized travel cost. The results show that under a given network scale, as the increase of block size, the percentage of average total travel time that happens inside the block increases, and the less friendly the system becomes for public transport. For example, the proportion of the average inside travel time to total time of public transportation users is 10% higher than that of private car users in a network with block size 600 m. The impact of block size on traffic performance should be taken more account into urban and traffic planning.

    References | Related Articles | Metrics
    Evaluation and Impact Analysis of Pedestrian-vehicle Conflict Severity
    PENG Yong, JIANG Pei, SHA Xiao-yu, ZOU Tian, LIU Song
    2019, 19(2): 175-181. 
    Abstract ( )   PDF (4636KB) ( )  

    The classification of conflict grade of pedestrians and vehicles at uncontrolled mid-block crosswalk is of great significance for the adoption of traffic safety strategies. This paper explored the influencing factors of the severity of pedestrian- vehicle conflict by means of traffic investigation and data analysis. Fourteen explanatory variables are identified by video capture, which integrates the three characteristics of human, vehicle and road. The explanatory variables are screened by correlation analysis between variables. Then a quantitative model of humanvehicle conflict based on Odered Probit regression analysis is established to determine the significant factors.

    References | Related Articles | Metrics
    Safe Distance Model for Overtaking on Two-lane Highway
    ZHANG Wen-hui, SUN Shu-rui, SU Yong-min
    2019, 19(2): 182-188. 
    Abstract ( )   PDF (3421KB) ( )  

    Traffic accidents induced by improper overtaking on the two-lane highways occur frequently. These traffic accidents tend to cause serious consequences. Therefore, a safe distance model during overtaking is proposed to provide theoretical basis for safe warning devices and assistant judging system. At first, this paper analyzes the types of collision during overtaking on a two-lane highway. The overtaking stage is divided into time segments based on the types of collision. The safe distance between vehicles in every overtaking period is analyzed. Then the safe distance model is established during overtaking. Taking speed remaining and speed increasing as examples, the small, medium and large type of vehicle serves as the leading vehicle respectively. The simulating parameters are input MATLAB to analyze and verify the effectiveness of the safe distance models. Finally, the critical safety distance curves of overtaking vehicle with leading vehicle and opposite vehicle are obtained. The results provide a theoretical basis for developing vehicle active safe system and preventing overtaking accidents.

    References | Related Articles | Metrics
    Data-driven Space-time Modeling and Propagation Study of Network-wide Sudden Congestion
    WEI Wei, LIU Ling, PENG Qi-yuan, CHEN Shao-kuan
    2019, 19(2): 189-195. 
    Abstract ( )   PDF (4453KB) ( )  

    For further analyzing the propagation and evolution characteristics of sudden congestion in actual road network, eliminating the distortion problem commonly existing in traditional simulation-based method because of superfluous assumptions or parameters, and taking advantage of the oceans of traffic flow data, an improved PLSSTAR model is developed to characterize the complex space-time propagation structure of sudden congestion on the basis of analyzing and identifying the sudden disruption using real traffic flow data. Then a congestion propagation effect evaluation method based on PLS-STAR is proposed based on the direct and indirect effects of space-time congestion propagation. By case studies on the road network in Beijing, it can be concluded that the reduction of road network’s service level is more attributed to the indirect effect of traffic congestion propagation, rather than the sudden increase of traffic volume. Therefore, there is still great potential to improve the service level of the urban road network by controlling congestion propagation effect.

    References | Related Articles | Metrics
    Spatial and Temporal Distribution of Occasional Congestion Based on Speed Variation
    SUN Jian-ping, GUO Ji-fu, ZHANG Xi, XU Chun-ling
    2019, 19(2): 196-201. 
    Abstract ( )   PDF (4285KB) ( )  

    The occurrence of traffic accidents will lead to the decrease of traffic speed and the accumulation of traffic flow in the upstream section, thus causing traffic congestion. This paper studies the spatial and temporal distribution characteristics of traffic congestion caused by traffic accidents on urban roads. Firstly, the vehicle speed variation characteristics under the impact of traffic accident were analyzed based on the accident data and segment speed data of Beijing. Then, a congestion judgment model based on speed difference was established, that on the base of traffic accident information, traffic flow and speed data of accident sections. The constraint conditions of its spatial and temporal dimensions are limited. The spatial and temporal scope of congestion caused by accident was quantitatively described, and the effect verification was conducted based on the simulation data and the real accident data of Beijing. The results show that this method can effectively describe the spatial and temporal distribution characteristics of traffic congestion caused by traffic accidents. This model is of great significance to clarify the spatial and temporal distribution characteristics of traffic congestion caused by accidents, to predict traffic congestion caused by accidents, and to formulate policies to alleviate traffic congestion.

    References | Related Articles | Metrics
    Risk Assessment of Highway Roadside Accidents Based on Bayesian Network
    CAI Ming, CHENG Guo-zhu, ZHANG Su-lu, WANG Bo, ZHOU Kan
    2019, 19(2): 202-208. 
    Abstract ( )   PDF (4202KB) ( )  

    It is necessary to take targeted measures according to roadside dangerous conditions. Therefore, it is urgent to study roadside accident risk evaluation. Based on accident simulation analysis, roadside accident severity was divided into four grades. Thresholds of driving speed, grade and height of side slope were given according to study on different roadside accident severity contributing factors. Bayesian network of roadside accident risk assessment was constructed. Based on thresholds of roadside accident contributing factors, calculation methods corresponding to single- factor, two- factor and three- factor were presented for probability of different roadside accidents severity. Lastly, case analysis was carried out by selecting typical roadside accident. Bayesian network calculating results show that the probability of no more than two turnovers is 0.929 and it is in conformity with accident simulation results, which proves the accuracy of the method.

    References | Related Articles | Metrics
    Markov Particle Filter Traffic Flow Prediction Model
    YU Quan, YAO Zong-han
    2019, 19(2): 209-215. 
    Abstract ( )   PDF (4346KB) ( )  

    In intelligent traffic system, short-term traffic flow prediction is one of the key technologies of traffic control and traffic guidance. Due to the inaccuracy of Markov traffic flow prediction model, according to the characteristics of traffic flow, a Markov particle filter traffic flow prediction model is proposed. On the one hand, after pretreatment of traffic flow, it can be used as sample data to predict future traffic flow in Markov model, which can better describe the trend of traffic flow. On the other hand, in view of the inaccuracy of the prediction results and the disadvantages of non- linear prediction instability, particle filter algorithm is used to update the prediction results and weights, and the sample re-selection process. After several iterations, the sample particles are closer to the actual prediction result, thus improving the prediction accuracy. Finally, the traffic flow detected by a detector in Changping District of Beijing is simulated, and the prediction results are compared with the traditional Markov chain. The results show that the 5-minute interval error and 1-hour interval error of the proposed Markov particle filter traffic flow prediction model are 6.14% and 6.04% respectively. It shows that the model has better applicability and stability, and the prediction accuracy is high.

    References | Related Articles | Metrics
    Feature Selection Algorithm in Short-time Traffic Flow Prediction
    WAN Fang, LI Guang-yu, JIA Ning, ZHU Ning
    2019, 19(2): 216-222. 
    Abstract ( )   PDF (3863KB) ( )  

    The short-term traffic flow prediction is an important foundation of intelligent transportation system, and its performance significantly influences the effectiveness of traffic control and guidance. For the nonparametric regression method in traffic flow prediction, one of the most important problems is state vectors selection. This paper presents a feature selection algorithm based on ReliefF and Delta Test to select feature vectors. Firstly, ReliefF algorithm is used to filter the state vectors according to the correlation between features and classes to speed up the efficiency of the algorithm. Then using Delta Test as performance index, genetic algorithm is used to optimize the weight of state component. Finally, the state vector selected by this method is compared with the state vector of time series and the simple Spatial-temporal correlation vector. Numerical results show that the proposed method outperforms the other two usually used methods under both general and abrupt traffic conditions.

    References | Related Articles | Metrics
    Short-term Forecasting of Supply-demand Gap under Online Car-hailing Services Based on Deep Learning
    GU Yuan-li, LI Meng, RUI Xiao-ping, LU Wen-qi, WANG Shuo
    2019, 19(2): 223-230. 
    Abstract ( )   PDF (4796KB) ( )  

    The results of supply- demand gap prediction for online car- hailing services in different areas can provide support for online car-hailing scheduling system, thereby improving efficiency and service levels. In order to realize the short-term forecast of supply-demand gap for online car-hailing services, this paper proposes a novel spatio- temporal deep learning model (S- TDL). The model is composed of three sub- models: spatiotemporal variable model, spatial attribute variable model and environment variable model. It can capture the impact of spatio- temporal correlation, regional difference and environmental change on supply- demand gap. Moreover, a feature selection method named feature clustering-maximum information coefficient two-stage feature selection is proposed to screen out the important features which are strongly correlated with the supply- demand gap, improve training efficiency. The experimental results show that the S-TDL model after feature selection achieves the better performance than the existing methods.

    References | Related Articles | Metrics
    Hierarchical Skills Personnel Scheduling of Foreign Airline Service
    FENG Xia, TANG Ling, LU Min
    2019, 19(2): 231-237. 
    Abstract ( )   PDF (3603KB) ( )  

    Personnel scheduling of foreign airline service is an important job for intelligent airport dispatching system. The scheduling methods of foreign airline service in China are mainly used manual arrangement, which led to low efficiency of scheduling, low balance of employees working hours, and difficulties in meeting various constraints. A mathematical mode of hierarchical skills personnel scheduling of foreign airline service is formulated with employees have hierarchical skills for tasks, various labor laws and regulations as constrains, and with the balance of employees working hours as the optimization goal. The tabu search algorithm is designed to solve the proposed model. Experiments were conducted on the actual data set of the Capital Airport’s Foreign Airline Service Department. The verification results show that compared with the existing manual scheduling scheme, the scheduling scheme obtained by using the model can meet all scheduling constraints, and the employee working hours is significantly improved.

    References | Related Articles | Metrics
    Urban Hotspot Travel Section Identification Method Based on Taxi GPS Large Data
    QU Zhao-wei, WANG Xin, SONG Xian-min, XIA Ying-ji, YUAN Mi-li
    2019, 19(2): 238-246. 
    Abstract ( )   PDF (7838KB) ( )  

    Due to the spatio- temporal interval between two consecutive taxi GPS points, the location where passengers get on or off the taxi is in a linear range. A method of trajectory density was proposed for further searching hotspots sections in the hotspots area where the hotspots location is fuzzy. Utilizing taxi GPS data of Chengdu, the spatio- temporal characteristics of the pick- up and drop- off location were analyzed by means of kernel density method; Based on the trajectory density method, the density of road network in Chunxi commercial district of Chengdu was calculated, the hotspots intensity of the section was divided, and the location of hotspots section was identified. The validity of the proposed method is verified by the actual travel demand distribution. The result shows that our method can effectively identify the hotspots sections where travel demand is strong. It can not only provide important reference for taxi drivers to find customers, but also give data support for traffic related departments to locate reasonable taxi stops.

    References | Related Articles | Metrics
    The Behavior Characteristics of Inter-city Travel under the Implication of Expressway Toll-free Policy during Holiday
    LIN Xiao-mei, SHAO Chun-fu, DONG Chun-jiao, WANG Sheng-you
    2019, 19(2): 247-254. 
    Abstract ( )   PDF (4036KB) ( )  

    Charge reduction measurements on existing toll roads are widely implemented to promote an efficient use of the expressways and to reduce congestion on the public transit networks during public holidays. However, some measurements have negative effects. A deep understanding of how the policy affects intercity traveling behavior is critical for better policymaking. This paper aims to investigate the behavior characteristics of joint mode and departure date choice under the implication of expressway toll- free policy. A nested Logit model is developed and estimated based on survey data during the Chinese Spring Festival holiday in 2017. The policy impact is further discussed by elasticity and scenario simulations. The results indicate that the expressway toll-free on different dates have very different effect on modal splits, as well as on car volume of rush days. Policy coordination regarding toll-free period is needed to ensure a significant effect on raising car share and reduce the road traffic congestion at the same time. The time- differential toll- free policy is recommended rather than the current toll-free policy or extending/shortening the toll-free period.

    References | Related Articles | Metrics