Zhuo Yan, Wang Tiantian, Shen Ruiyuan, Xie Jingsong, Yang Jingsong, Zhang Guoqin, Tian Hongqi, Liang Xifeng
With the improvement of the running speed of China's high-speed trains, the demands for running status monitoring and security assurance of High-speed Electric Multiple Units(EMU) have increased significantly. However, the current safety monitoring systems are independent, which is not conducive to the comprehensive monitoring and information sharing of the whole vehicle. The temperature monitoring of running gear is insensitive to early failures. How to develop a train operation safety monitoring system with strong engineering implementation and high integration is a key problem to be solved. For the monitoring of running stationarity, frame stability and running gear health of China's high-speed trains, an integrated safety monitoring system framework is designed, and the logic and algorithm for diagnosis of stationarity, stability and health states of rotating parts are constructed. A monitoring software which fused the temperature, high and low frequency vibration data is developed, and the design and installation of the vibration temperature composite sensors are completed. The research results have realized the integration and comprehensive processing of multiple monitoring systems, completed the improvement from single component and single vehicle level safety monitoring to multiple systems, vehicle level and interactive monitoring. In the process of real vehicle application, the developed monitoring system acquires the vehicle operation status data in real time and accurately. The constructed diagnosis algorithm and logic evaluate the vehicle operation status timely and accurately, and avoid the evolution from fault to accident. The research results show that the integrated safety monitoring system can provide technical support for train operation safety.
{"title":"Development and engineering application of integrated safety monitoring system for China's high-speed trains","authors":"Zhuo Yan, Wang Tiantian, Shen Ruiyuan, Xie Jingsong, Yang Jingsong, Zhang Guoqin, Tian Hongqi, Liang Xifeng","doi":"10.1093/tse/tdad017","DOIUrl":"https://doi.org/10.1093/tse/tdad017","url":null,"abstract":"\u0000 With the improvement of the running speed of China's high-speed trains, the demands for running status monitoring and security assurance of High-speed Electric Multiple Units(EMU) have increased significantly. However, the current safety monitoring systems are independent, which is not conducive to the comprehensive monitoring and information sharing of the whole vehicle. The temperature monitoring of running gear is insensitive to early failures. How to develop a train operation safety monitoring system with strong engineering implementation and high integration is a key problem to be solved. For the monitoring of running stationarity, frame stability and running gear health of China's high-speed trains, an integrated safety monitoring system framework is designed, and the logic and algorithm for diagnosis of stationarity, stability and health states of rotating parts are constructed. A monitoring software which fused the temperature, high and low frequency vibration data is developed, and the design and installation of the vibration temperature composite sensors are completed. The research results have realized the integration and comprehensive processing of multiple monitoring systems, completed the improvement from single component and single vehicle level safety monitoring to multiple systems, vehicle level and interactive monitoring. In the process of real vehicle application, the developed monitoring system acquires the vehicle operation status data in real time and accurately. The constructed diagnosis algorithm and logic evaluate the vehicle operation status timely and accurately, and avoid the evolution from fault to accident. The research results show that the integrated safety monitoring system can provide technical support for train operation safety.","PeriodicalId":52804,"journal":{"name":"Transportation Safety and Environment","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43677238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to improve the emergency management capability of the urban rail transit system and reduce accidents during metro operation, an emergency management capability evaluation method combining theAnalytic Hierarchy Process (AHP) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is proposed. Based on the PPRR (Prevention Preparation Response Recovery) model, the factors influencing the emergency management capability of the urban rail transit system are summarized from the perspective of ‘human, machine, environment, and management’. Then, an emergency management capability evaluation index system containing 20 secondary indicators is constructed in four stages: emergency prevention, emergency preparation, emergency response, and emergency recovery. The weights of indicators are calculated using the AHP method, and the closeness of each indicator to the optimal solution is analyzed with the TOPSIS method. Finally, take the Beijing metro line 13 as an example to investigate the level of emergency management capability of urban rail transit. The results show that the emergency management capability of Beijing urban rail transit system is ‘well’, among which hazard prevention measures (0.31) and emergency response team (0.34) have a greater weight on the emergency management capability of rail transit. The model can more accurately assess the emergency management capability of urban rail transit and provide a basis for emergency event management.
{"title":"Emergency Management Capacity assessment for Urban Rail transit——An example of Beijing Metro Line 13","authors":"J. Liu, Yun-song Qi, W. Wang","doi":"10.1093/tse/tdad015","DOIUrl":"https://doi.org/10.1093/tse/tdad015","url":null,"abstract":"\u0000 In order to improve the emergency management capability of the urban rail transit system and reduce accidents during metro operation, an emergency management capability evaluation method combining theAnalytic Hierarchy Process (AHP) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is proposed. Based on the PPRR (Prevention Preparation Response Recovery) model, the factors influencing the emergency management capability of the urban rail transit system are summarized from the perspective of ‘human, machine, environment, and management’. Then, an emergency management capability evaluation index system containing 20 secondary indicators is constructed in four stages: emergency prevention, emergency preparation, emergency response, and emergency recovery. The weights of indicators are calculated using the AHP method, and the closeness of each indicator to the optimal solution is analyzed with the TOPSIS method. Finally, take the Beijing metro line 13 as an example to investigate the level of emergency management capability of urban rail transit. The results show that the emergency management capability of Beijing urban rail transit system is ‘well’, among which hazard prevention measures (0.31) and emergency response team (0.34) have a greater weight on the emergency management capability of rail transit. The model can more accurately assess the emergency management capability of urban rail transit and provide a basis for emergency event management.","PeriodicalId":52804,"journal":{"name":"Transportation Safety and Environment","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42556396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xinyuan Liu, Jinjun Tang, Chen Yuan, Fan Gao, Xizhi Ding
Understanding the characteristics of time and distance gaps between the primary and second crashes is crucial for preventing secondary crash occurrences and improving road safety. Although previous studies have tried to analyze the variation of gaps, there is limited evidence in quantifying the relationships between different gaps and various influential factors. This study proposed a two-layer Stacking framework to discuss the time and distance gaps. Specifically, the framework took Random Forests, Gradient Boosting Decision Tree, and eXtreme Gradient Boosting as the base classifiers in the first layer and applied Logistic Regression as a combiner in the second layer. On this basis, the Local Interpretable Model-agnostic Explanations (LIME) technology was used to interpret the output of the Stacking model from both local and global perspectives. Through secondary crash identification and feature selection, 346 secondary crashes and 22 crash-related factors were collected from California interstate freeways. The results showed that the Stacking model outperformed base models evaluated by accuracy, precision, and recall indicators. The explanations based on LIME suggest that collision type, distance, speed, and volume are the critical features that affect the time and distance gaps. Higher volume can prolong queue length and increase the distance gap from the secondary to primary crashes. And collision types, peak periods, workday, truck involved, and tow away likely induce a long-distance gap. Conversely, there is a shorter distance gap when secondary roads run in the same direction and are close to the primary roads. Lower speed is a significant factor resulting in a long-time gap, while the higher speed is correlated with a short-time gap. These results are expected to provide insights into how contributory features affect the time and distance gaps and help decision-makers develop accurate decisions to prevent secondary crashes.
{"title":"Examining the characteristics between time and distance gaps of secondary crashes","authors":"Xinyuan Liu, Jinjun Tang, Chen Yuan, Fan Gao, Xizhi Ding","doi":"10.1093/tse/tdad014","DOIUrl":"https://doi.org/10.1093/tse/tdad014","url":null,"abstract":"\u0000 Understanding the characteristics of time and distance gaps between the primary and second crashes is crucial for preventing secondary crash occurrences and improving road safety. Although previous studies have tried to analyze the variation of gaps, there is limited evidence in quantifying the relationships between different gaps and various influential factors. This study proposed a two-layer Stacking framework to discuss the time and distance gaps. Specifically, the framework took Random Forests, Gradient Boosting Decision Tree, and eXtreme Gradient Boosting as the base classifiers in the first layer and applied Logistic Regression as a combiner in the second layer. On this basis, the Local Interpretable Model-agnostic Explanations (LIME) technology was used to interpret the output of the Stacking model from both local and global perspectives. Through secondary crash identification and feature selection, 346 secondary crashes and 22 crash-related factors were collected from California interstate freeways. The results showed that the Stacking model outperformed base models evaluated by accuracy, precision, and recall indicators. The explanations based on LIME suggest that collision type, distance, speed, and volume are the critical features that affect the time and distance gaps. Higher volume can prolong queue length and increase the distance gap from the secondary to primary crashes. And collision types, peak periods, workday, truck involved, and tow away likely induce a long-distance gap. Conversely, there is a shorter distance gap when secondary roads run in the same direction and are close to the primary roads. Lower speed is a significant factor resulting in a long-time gap, while the higher speed is correlated with a short-time gap. These results are expected to provide insights into how contributory features affect the time and distance gaps and help decision-makers develop accurate decisions to prevent secondary crashes.","PeriodicalId":52804,"journal":{"name":"Transportation Safety and Environment","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41849294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, an adaptive composite anti-disturbance control of heavy haul trains (HHTs) is proposed. First, the mechanical principle and characteristics of couplers are analyzed and the longitudinal multi-particles nonlinear dynamic model of HHTs is established, which can satisfy that the forces of vehicles in different positions are different. Subsequently, a radial basis function network (RBFNN) is employed to approximate the uncertainties of HHTs, and a nonlinear disturbance observer (NDO) is constructed to estimate the approximation error and external disturbances. To indicate and improve the approximation accuracy, a serial-parallel identification model of HHTs is constructed to generate a prediction error, and an adaptive composite anti-disturbance control scheme is developed, where the prediction error and tracking error are employed to update RBFNN weights and an auxiliary variable of NDO. Finally, the feasibility and effectiveness of proposed control scheme are demonstrated through the Lyapunov theory and simulation experiments.
{"title":"Adaptive composite anti-disturbance control for heavy haul trains","authors":"Longsheng Chen, Hui Yang","doi":"10.1093/tse/tdad009","DOIUrl":"https://doi.org/10.1093/tse/tdad009","url":null,"abstract":"\u0000 In this paper, an adaptive composite anti-disturbance control of heavy haul trains (HHTs) is proposed. First, the mechanical principle and characteristics of couplers are analyzed and the longitudinal multi-particles nonlinear dynamic model of HHTs is established, which can satisfy that the forces of vehicles in different positions are different. Subsequently, a radial basis function network (RBFNN) is employed to approximate the uncertainties of HHTs, and a nonlinear disturbance observer (NDO) is constructed to estimate the approximation error and external disturbances. To indicate and improve the approximation accuracy, a serial-parallel identification model of HHTs is constructed to generate a prediction error, and an adaptive composite anti-disturbance control scheme is developed, where the prediction error and tracking error are employed to update RBFNN weights and an auxiliary variable of NDO. Finally, the feasibility and effectiveness of proposed control scheme are demonstrated through the Lyapunov theory and simulation experiments.","PeriodicalId":52804,"journal":{"name":"Transportation Safety and Environment","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45118407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aiming at the robustness issue in high-speed trains operation control, this paper proposes a model-free adaptive control (MFAC) scheme to suppress disturbance. Firstly, the dynamic linearization data model of train system under the action of measurement disturbance is given, and the Kalman filter based on this model is derived under the minimum variance estimation criterion. Then, according to Kalman filter, an anti-interference MFAC scheme is designed. This scheme only needs the input and output data of the controlled system to realize the MFAC of the train under strong disturbance. Finally, the simulation experiment of CRH380A high-speed trains is carried out and compared with the traditional MFAC and the MFAC with attenuation factor: the proposed control algorithm can effectively suppress the measurement disturbance, and can obtain smaller tracking error and larger data signal to noise ratio with better applicability.
{"title":"Model-free adaptive robust control method for high-speed trains","authors":"Li Zhong-qi, Zhou Liang, Yang Hui, Yan Yue","doi":"10.1093/tse/tdad013","DOIUrl":"https://doi.org/10.1093/tse/tdad013","url":null,"abstract":"\u0000 Aiming at the robustness issue in high-speed trains operation control, this paper proposes a model-free adaptive control (MFAC) scheme to suppress disturbance. Firstly, the dynamic linearization data model of train system under the action of measurement disturbance is given, and the Kalman filter based on this model is derived under the minimum variance estimation criterion. Then, according to Kalman filter, an anti-interference MFAC scheme is designed. This scheme only needs the input and output data of the controlled system to realize the MFAC of the train under strong disturbance. Finally, the simulation experiment of CRH380A high-speed trains is carried out and compared with the traditional MFAC and the MFAC with attenuation factor: the proposed control algorithm can effectively suppress the measurement disturbance, and can obtain smaller tracking error and larger data signal to noise ratio with better applicability.","PeriodicalId":52804,"journal":{"name":"Transportation Safety and Environment","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45034355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the research on the new generation of intelligent rail transit system, the prevention of train collision safety accidents is still a focus. Virtual coupling technology is a technology that cooperatively controls the running speed and interval distance of two or more trains through Train-to-Train(T2T) train workshop direct communication technology. The aim is to form a coordinated logical whole and jointly complete the train control and dispatching organization. In this paper, a virtual coupling train formation control method based on model predictive control (MPC) framework is proposed. From the aspects of the establishment of virtual coupling system, the construction of MPC model and decoupling method, how to integrate virtual coupling technology into the rail transit train collision protection is studied. And the safety and reliability of the system are calculated through fault tree and the method of constructing reliability function. The research shows that, if virtual coupling technology is used as a method of train collision protection, the overall safety and reliability of the train control system will be improved.
{"title":"Research on virtual coupling technology in rail transit train collision protection","authors":"Gaosong Li, Jinbai Zou, Weijie Ma, Meng Lan","doi":"10.1093/tse/tdad012","DOIUrl":"https://doi.org/10.1093/tse/tdad012","url":null,"abstract":"\u0000 In the research on the new generation of intelligent rail transit system, the prevention of train collision safety accidents is still a focus. Virtual coupling technology is a technology that cooperatively controls the running speed and interval distance of two or more trains through Train-to-Train(T2T) train workshop direct communication technology. The aim is to form a coordinated logical whole and jointly complete the train control and dispatching organization. In this paper, a virtual coupling train formation control method based on model predictive control (MPC) framework is proposed. From the aspects of the establishment of virtual coupling system, the construction of MPC model and decoupling method, how to integrate virtual coupling technology into the rail transit train collision protection is studied. And the safety and reliability of the system are calculated through fault tree and the method of constructing reliability function. The research shows that, if virtual coupling technology is used as a method of train collision protection, the overall safety and reliability of the train control system will be improved.","PeriodicalId":52804,"journal":{"name":"Transportation Safety and Environment","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49363006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Tian, Tiantian Wang, Lei Xu, M. Sha, Shujun Chen, Zeyun Yang, Yan Zhu, Dawei Chen, Hengkui Li, Lei Zhang, Bosen Qian, X. Tian
Contagious pathogens like COVID-19 transmitted via respiratory droplets spread effortlessly in the passenger compartment of transport, significantly jeopardizing passengers’ safety when taking public transportation. To date, studies on the fundamental theories of airborne droplet transmission and the engineering application of decontamination techniques are insufficient for the prevention and control of pathogens transmitting in the compartment of passenger transport. It is essential to systematically investigate the control approaches to restrain pathogens from transmitting in passenger compartments. Herein, a theoretical framework for calculating the transmission of pathogens in a complex compartment environment was proposed, and experimental platforms that satisfy the Biosafety Level-2 Laboratory safety level for compartment environment simulations were built based on a set of real train cabins. On these bases, numerical investigations on motion of pathogen-laden droplets were conducted, and decontamination techniques were examined experimentally. Thereby, control measures on the pathogen transmission and pathogen decontamination schemes were proposed. Moreover, highly efficient decontamination devices were developed, and coping strategies for epidemic emergencies were devised. The outcomes provide theoretical and technical support for developing the next generation of transportation and the prevention and control measures cooperatively considering regular and pandemic times.
{"title":"Research and Development of Prevention and Control Measures on the Transmission of Pathogens in Compartments of Passenger Transport","authors":"H. Tian, Tiantian Wang, Lei Xu, M. Sha, Shujun Chen, Zeyun Yang, Yan Zhu, Dawei Chen, Hengkui Li, Lei Zhang, Bosen Qian, X. Tian","doi":"10.1093/tse/tdad011","DOIUrl":"https://doi.org/10.1093/tse/tdad011","url":null,"abstract":"\u0000 Contagious pathogens like COVID-19 transmitted via respiratory droplets spread effortlessly in the passenger compartment of transport, significantly jeopardizing passengers’ safety when taking public transportation. To date, studies on the fundamental theories of airborne droplet transmission and the engineering application of decontamination techniques are insufficient for the prevention and control of pathogens transmitting in the compartment of passenger transport. It is essential to systematically investigate the control approaches to restrain pathogens from transmitting in passenger compartments. Herein, a theoretical framework for calculating the transmission of pathogens in a complex compartment environment was proposed, and experimental platforms that satisfy the Biosafety Level-2 Laboratory safety level for compartment environment simulations were built based on a set of real train cabins. On these bases, numerical investigations on motion of pathogen-laden droplets were conducted, and decontamination techniques were examined experimentally. Thereby, control measures on the pathogen transmission and pathogen decontamination schemes were proposed. Moreover, highly efficient decontamination devices were developed, and coping strategies for epidemic emergencies were devised. The outcomes provide theoretical and technical support for developing the next generation of transportation and the prevention and control measures cooperatively considering regular and pandemic times.","PeriodicalId":52804,"journal":{"name":"Transportation Safety and Environment","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47372435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Based on the 2012–2018 accident statistics on the Hunan Provincial Expressway in China, this paper analyzes the proportion to which various factors contribute to accidents, as well as the trends over time. From 2012 to 2018, the total number of general procedure handling accidents (i.e. major accidents) increased first and then decreased, while the number of accidents and deaths per 1 000 kilometers decreased year by year. The total number of simple procedure handling accidents (i.e. minor accidents) increased year by year, but the number of accidents per 1 000 kilometers remained relatively stable. Speeding, fatigued driving, improper driving operation, failure to maintain a safe distance from the preceding vehicle, and pedestrians entering the expressway are the main causes of general procedure handling accidents. Failure to maintain a safe distance from the preceding vehicle as required and improper driving operation accounted for approximately 2/3 of the simple procedure handling accidents. In view of the accidents caused by these factors, how to use law enforcement, education, science and technology, and facilities construction to further reduce the occurrence of expressway traffic accidents is discussed.
{"title":"Analysis of the causes of expressway traffic accidents based on statistics of accidents on the Hunan Provincial expressway in 2012-2018","authors":"Xinyu Liu, Shengjun Huang, Qun Chen","doi":"10.1093/tse/tdad010","DOIUrl":"https://doi.org/10.1093/tse/tdad010","url":null,"abstract":"\u0000 Based on the 2012–2018 accident statistics on the Hunan Provincial Expressway in China, this paper analyzes the proportion to which various factors contribute to accidents, as well as the trends over time. From 2012 to 2018, the total number of general procedure handling accidents (i.e. major accidents) increased first and then decreased, while the number of accidents and deaths per 1 000 kilometers decreased year by year. The total number of simple procedure handling accidents (i.e. minor accidents) increased year by year, but the number of accidents per 1 000 kilometers remained relatively stable. Speeding, fatigued driving, improper driving operation, failure to maintain a safe distance from the preceding vehicle, and pedestrians entering the expressway are the main causes of general procedure handling accidents. Failure to maintain a safe distance from the preceding vehicle as required and improper driving operation accounted for approximately 2/3 of the simple procedure handling accidents. In view of the accidents caused by these factors, how to use law enforcement, education, science and technology, and facilities construction to further reduce the occurrence of expressway traffic accidents is discussed.","PeriodicalId":52804,"journal":{"name":"Transportation Safety and Environment","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47586139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A notable feature of a city or a region with close economic and social connections with its neighbors is reflected in its highly mixed local and external traffic, and in some cases the external traffic volume is almost as high as that of local traffic. Whilst local traffic volume may be largely made up of the same regular local commuters making frequent trips, the external traffic from outside of the city (region) may not be the same people making regular trips to/from the city, but from a large pool of people making in-frequent trips to/from the city, the existence of external traffic is proven by data from the license plate recognition system of road vehicle in Changde of China. The function of value of time correlated with income/wage rate and trip frequency is exploited and verified statistically. The time value distorted by trip frequency is defined as perceived time value (PTV), which also influences the way travelers perceive any travel impedance such as congestion delay and toll charges. This paper analyses the price of anarchy (POA) when explicitly considering the travel frequency of the trip-makers and their PTV, and compares with previous analysis without considering travel frequency. We show that when travel frequency is considered, the optimal toll of congested road pricing schemes which converts road traffic flow from User Equilibrium into System Optimization, is much lower than that without considering travel frequency, and cost of license plate auction cannot be treated as congestion toll, which is only threshold of vehicle ownership. That travelers choose route by PTV rather than TV (time value) is proven by an example of Heishipu bridge of Changsha of Hunan Province in China.
{"title":"How does trip frequency distort time value to impact congestion charging scheme?","authors":"Mao-sheng Li, H. Li","doi":"10.1093/tse/tdad008","DOIUrl":"https://doi.org/10.1093/tse/tdad008","url":null,"abstract":"\u0000 A notable feature of a city or a region with close economic and social connections with its neighbors is reflected in its highly mixed local and external traffic, and in some cases the external traffic volume is almost as high as that of local traffic. Whilst local traffic volume may be largely made up of the same regular local commuters making frequent trips, the external traffic from outside of the city (region) may not be the same people making regular trips to/from the city, but from a large pool of people making in-frequent trips to/from the city, the existence of external traffic is proven by data from the license plate recognition system of road vehicle in Changde of China. The function of value of time correlated with income/wage rate and trip frequency is exploited and verified statistically. The time value distorted by trip frequency is defined as perceived time value (PTV), which also influences the way travelers perceive any travel impedance such as congestion delay and toll charges. This paper analyses the price of anarchy (POA) when explicitly considering the travel frequency of the trip-makers and their PTV, and compares with previous analysis without considering travel frequency. We show that when travel frequency is considered, the optimal toll of congested road pricing schemes which converts road traffic flow from User Equilibrium into System Optimization, is much lower than that without considering travel frequency, and cost of license plate auction cannot be treated as congestion toll, which is only threshold of vehicle ownership. That travelers choose route by PTV rather than TV (time value) is proven by an example of Heishipu bridge of Changsha of Hunan Province in China.","PeriodicalId":52804,"journal":{"name":"Transportation Safety and Environment","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46945879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presents a hybrid data-mining framework based on feature selection algorithms and clustering methods to perform the pattern discovery of high-speed railway train rescheduling strategies (RS). The proposed model is composed of two states. In the first state, decision tree, random forest, Gradient Boosting Decision Tree (GBDT), and eXtreme Gradient Boosting (XGBoost) models are used to investigate the importance of features. The features that have a high influence on RS are first selected. In the second state, a K-means clustering method is used to uncover the interdependences between RS and the influencing features, based on the results in the first state. The proposed method can determine the quantitative relationships between RS and influencing factors. The results clearly show the influences of the factors on RS, the possibilities of different train operation RS under different situations, as well as some key time periods and key trains that the controllers should pay more attention to. The research in this paper can help train traffic controllers better understand the train operation patterns and provides direction for optimizing rail traffic RS.
{"title":"A hybrid data-mining framework for train rescheduling strategy pattern discovery","authors":"Rui Chen, Xu Ge, Ping Huang, Chao Wen","doi":"10.1093/tse/tdad007","DOIUrl":"https://doi.org/10.1093/tse/tdad007","url":null,"abstract":"\u0000 This study presents a hybrid data-mining framework based on feature selection algorithms and clustering methods to perform the pattern discovery of high-speed railway train rescheduling strategies (RS). The proposed model is composed of two states. In the first state, decision tree, random forest, Gradient Boosting Decision Tree (GBDT), and eXtreme Gradient Boosting (XGBoost) models are used to investigate the importance of features. The features that have a high influence on RS are first selected. In the second state, a K-means clustering method is used to uncover the interdependences between RS and the influencing features, based on the results in the first state. The proposed method can determine the quantitative relationships between RS and influencing factors. The results clearly show the influences of the factors on RS, the possibilities of different train operation RS under different situations, as well as some key time periods and key trains that the controllers should pay more attention to. The research in this paper can help train traffic controllers better understand the train operation patterns and provides direction for optimizing rail traffic RS.","PeriodicalId":52804,"journal":{"name":"Transportation Safety and Environment","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42169855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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