Pub Date : 2025-05-04DOI: 10.1080/23249935.2023.2243345
Liyou Li , Weilin Ren , Rongjun Cheng
Advanced driver assistance system (ADAS) plays an important role in the transition period before the full maturity of self-driving technology. In this paper, an intelligent driver model with multiple time delays (IDM-MTD) is established to describe the dynamic characteristics of vehicles equipped with ADAS. Moreover, a control term that considers the velocity difference between the current and historical moment is selected for assistance driving. A novel framework is proposed to determine control parameters in controlled IDM-MTD. The definite integral stability method (DISM) is integrated into the framework to constrain the range of parameters that make the system stable. In the control strategy design process, this paper places significant emphasis on the implementation of the DISM modification to effectively address redundant iteration steps by exploiting the characteristic of bifurcation. Through numerical simulation, a two-dimensional optimal parameter combination is found, which not only stabilizes traffic flow but also produces minimal gasoline consumption.
{"title":"Bifurcation control based on improved intelligent driver model considering stability and minimum gasoline consumption","authors":"Liyou Li , Weilin Ren , Rongjun Cheng","doi":"10.1080/23249935.2023.2243345","DOIUrl":"10.1080/23249935.2023.2243345","url":null,"abstract":"<div><div>Advanced driver assistance system (ADAS) plays an important role in the transition period before the full maturity of self-driving technology. In this paper, an intelligent driver model with multiple time delays (IDM-MTD) is established to describe the dynamic characteristics of vehicles equipped with ADAS. Moreover, a control term that considers the velocity difference between the current and historical moment is selected for assistance driving. A novel framework is proposed to determine control parameters in controlled IDM-MTD. The definite integral stability method (DISM) is integrated into the framework to constrain the range of parameters that make the system stable. In the control strategy design process, this paper places significant emphasis on the implementation of the DISM modification to effectively address redundant iteration steps by exploiting the characteristic of bifurcation. Through numerical simulation, a two-dimensional optimal parameter combination is found, which not only stabilizes traffic flow but also produces minimal gasoline consumption.</div></div>","PeriodicalId":48871,"journal":{"name":"Transportmetrica A-Transport Science","volume":"21 2","pages":"Pages 1-22"},"PeriodicalIF":3.6,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44620378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Connected and Autonomous Vehicles (CAVs) may exhibit different driving and route choice behaviours compared to Human-Driven Vehicles (HDVs), which can result in a mixed traffic flow with multiple classes of route choice behaviour. Therefore, it is necessary to solve the Multiclass Traffic Assignment Problem (TAP) for mixed traffic flow. However, most existing studies have relied on analytical solutions. Furthermore, simulation-based methods have not fully considered all of CAVs’ potential capabilities. This study presents an open-source solution framework for the multiclass simulation-based TAP in mixed traffic of CAVs and HDVs. The proposed model assumes that CAVs follow system optimal with rerouting capabilities, while HDVs follow user equilibrium. It also considers the impact of CAVs on road capacity at both micro and meso scales. The proposed model is demonstrated through three case studies. This study provides a valuable tool that can consider several assumptions for better understanding the impact of CAVs on mixed traffic flow.
{"title":"A multiclass simulation-based dynamic traffic assignment model for mixed traffic flow of connected and autonomous vehicles and human-driven vehicles","authors":"Behzad Bamdad Mehrabani , Jakob Erdmann , Luca Sgambi , Seyedehsan Seyedabrishami , Maaike Snelder","doi":"10.1080/23249935.2023.2257805","DOIUrl":"10.1080/23249935.2023.2257805","url":null,"abstract":"<div><div>Connected and Autonomous Vehicles (CAVs) may exhibit different driving and route choice behaviours compared to Human-Driven Vehicles (HDVs), which can result in a mixed traffic flow with multiple classes of route choice behaviour. Therefore, it is necessary to solve the Multiclass Traffic Assignment Problem (TAP) for mixed traffic flow. However, most existing studies have relied on analytical solutions. Furthermore, simulation-based methods have not fully considered all of CAVs’ potential capabilities. This study presents an open-source solution framework for the multiclass simulation-based TAP in mixed traffic of CAVs and HDVs. The proposed model assumes that CAVs follow system optimal with rerouting capabilities, while HDVs follow user equilibrium. It also considers the impact of CAVs on road capacity at both micro and meso scales. The proposed model is demonstrated through three case studies. This study provides a valuable tool that can consider several assumptions for better understanding the impact of CAVs on mixed traffic flow.</div></div>","PeriodicalId":48871,"journal":{"name":"Transportmetrica A-Transport Science","volume":"21 2","pages":"Pages 1-32"},"PeriodicalIF":3.6,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134910622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-04DOI: 10.1080/23249935.2023.2267685
Yu Rao , Xiaoyun Feng , Qingyuan Wang , Pengfei Sun
When a train travels in a multi-trains system, the power flow of other trains and the track grades make up the spatial–temporal area (STA) for the train. Finding the optimal solution for the energy-efficient train control problem in STA can help reduce the net energy consumption. This paper studies the analytic method to obtain the optimal solution. In Part 1, we propose an algorithm specifically designed for this problem. The underlying structure of the algorithm is the connection between three optimal states through the optimal feasible strategy. We propose an algebraic method to calculate the optimal feasible strategy and discuss how it intersects with the speed limit. In Part 2, we will discuss the optimality and uniqueness of the optimal feasible strategy. Case studies using data from a real freight railway line are given to demonstrate the effectiveness of the proposed algorithm.
{"title":"The optimal solution to the energy-efficient train control in a multi-trains system-part 1: the algorithm design","authors":"Yu Rao , Xiaoyun Feng , Qingyuan Wang , Pengfei Sun","doi":"10.1080/23249935.2023.2267685","DOIUrl":"10.1080/23249935.2023.2267685","url":null,"abstract":"<div><div>When a train travels in a multi-trains system, the power flow of other trains and the track grades make up the spatial–temporal area (STA) for the train. Finding the optimal solution for the energy-efficient train control problem in STA can help reduce the net energy consumption. This paper studies the analytic method to obtain the optimal solution. In Part 1, we propose an algorithm specifically designed for this problem. The underlying structure of the algorithm is the connection between three optimal states through the optimal feasible strategy. We propose an algebraic method to calculate the optimal feasible strategy and discuss how it intersects with the speed limit. In Part 2, we will discuss the optimality and uniqueness of the optimal feasible strategy. Case studies using data from a real freight railway line are given to demonstrate the effectiveness of the proposed algorithm.</div></div>","PeriodicalId":48871,"journal":{"name":"Transportmetrica A-Transport Science","volume":"21 2","pages":"Pages 1-29"},"PeriodicalIF":3.6,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135883168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-04DOI: 10.1080/23249935.2023.2259014
Haiming Hao , Hui Jin
Lane-based fixed-time signal is basic to various signal control strategies. It performs well in maximizing road capacity, but is faced with significant challenge in minimizing traffic delay. This study validates the convexity of lane-based fixed-time signal model for delay minimization, when lane markings are determined as well as flow factors. Thus Breadth first search algorithm is developed to enumerate the feasible lane markings, which are then screened with flow factors. Cutting plane algorithm is applied to the CMINLP for each feasible lane markings, where the non-linear delay function is converted to a series of linear ones, until the relaxed delay converges to the actual delay. Branch pruning strategy is established for efficiency, to eliminate the lane markings with uncompetitive delay. Numerical analyses follow to validate the proposed algorithm. This research promotes the redesign of lane-based fixed-time signal control.
{"title":"Convexity and global optimisation of lane-based fixed-time signal model for delay minimisation at an isolated intersection","authors":"Haiming Hao , Hui Jin","doi":"10.1080/23249935.2023.2259014","DOIUrl":"10.1080/23249935.2023.2259014","url":null,"abstract":"<div><div>Lane-based fixed-time signal is basic to various signal control strategies. It performs well in maximizing road capacity, but is faced with significant challenge in minimizing traffic delay. This study validates the convexity of lane-based fixed-time signal model for delay minimization, when lane markings are determined as well as flow factors. Thus Breadth first search algorithm is developed to enumerate the feasible lane markings, which are then screened with flow factors. Cutting plane algorithm is applied to the CMINLP for each feasible lane markings, where the non-linear delay function is converted to a series of linear ones, until the relaxed delay converges to the actual delay. Branch pruning strategy is established for efficiency, to eliminate the lane markings with uncompetitive delay. Numerical analyses follow to validate the proposed algorithm. This research promotes the redesign of lane-based fixed-time signal control.</div></div>","PeriodicalId":48871,"journal":{"name":"Transportmetrica A-Transport Science","volume":"21 2","pages":"Pages 1-23"},"PeriodicalIF":3.6,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136341945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-04DOI: 10.1080/23249935.2023.2261044
Chengliang Liu , Bangjuan Wang , Hong Zhang
Due to the airline hubs’ organisation such as linkage, hierarchical structure, and hub-and-spoke remains a mystery at a global scale. Thereby, the research aims to unravel the spatial organisation of airline hubs in the air transport network (ATN) by using weighted ego network analysis (WENA), Ht-index, and maximum leaf spanning tree (MLST) at multi-scales. The findings provide valuable insights into the status of different regional cities in the ATN and the critical relationship between hubs and their associated spokes. The result shows that the ATN is a legibly hierarchical network, and three types of airline hubs, i.e. global, international, and regional hubs have been identified. Additionally, the study reveals that the ATN is made up of several regional hub-and-spoke systems, where hubs dominate their subgraphs, with range and geographical proximity effects are observed. Finally, the role of airline hubs as international gateways and domestic hubs is also noted.
{"title":"Mapping the spatial organisation of air transport network by WENA-MLST analysis","authors":"Chengliang Liu , Bangjuan Wang , Hong Zhang","doi":"10.1080/23249935.2023.2261044","DOIUrl":"10.1080/23249935.2023.2261044","url":null,"abstract":"<div><div>Due to the airline hubs’ organisation such as linkage, hierarchical structure, and hub-and-spoke remains a mystery at a global scale. Thereby, the research aims to unravel the spatial organisation of airline hubs in the air transport network (ATN) by using weighted ego network analysis (WENA), Ht-index, and maximum leaf spanning tree (MLST) at multi-scales. The findings provide valuable insights into the status of different regional cities in the ATN and the critical relationship between hubs and their associated spokes. The result shows that the ATN is a legibly hierarchical network, and three types of airline hubs, i.e. global, international, and regional hubs have been identified. Additionally, the study reveals that the ATN is made up of several regional hub-and-spoke systems, where hubs dominate their subgraphs, with range and geographical proximity effects are observed. Finally, the role of airline hubs as international gateways and domestic hubs is also noted.</div></div>","PeriodicalId":48871,"journal":{"name":"Transportmetrica A-Transport Science","volume":"21 2","pages":"Pages 1-26"},"PeriodicalIF":3.6,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136060128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-04DOI: 10.1080/23249935.2023.2264949
Zhao Zhang , Yun Yuan , Mingchen Li , Pan Lu , Xianfeng Terry Yang
Recent studies have shown the successful implementation of classical model-based approaches (e.g. macroscopic traffic flow modelling) and data-driven approaches (e.g. machine learning – ML) to model freeway traffic patterns, while both have their limitations. Even though model-based approaches could depict real-world traffic dynamics, they could potentially lead to inaccurate estimations due to traffic fluctuations and uncertainties. In data-driven models, the acquisition of sufficient high-quality data is required to ensure the model performance. However, many transportation applications often suffer from data shortage and noises. To overcome those limitations, this study aims to introduce and evaluate a new model, named as physics-guided machine learning (PGML), that integrates the classical traffic flow model (TFM) with the machine learning technique. This PGML model leverages the output of a traffic flow model along with observational features to generate estimations using a neural network framework. More specifically, it applies physics-guided loss functions in the learning objective of neural networks to ensure that the model not only consists with the training set but also shows lower errors on the known physics of the unlabelled set. To illustrate the effectiveness of the PGML, this study implements empirical studies with a real-world dataset collected from a stretch of I-15 freeway in Utah. Experimental study results show that the proposed PGML model could outperform the other compatible methods, including calibrated traffic flow models, pure machine learning methods, and physics unguided machine learning (PUML).
{"title":"Empirical study of the effects of physics-guided machine learning on freeway traffic flow modelling: model comparisons using field data","authors":"Zhao Zhang , Yun Yuan , Mingchen Li , Pan Lu , Xianfeng Terry Yang","doi":"10.1080/23249935.2023.2264949","DOIUrl":"10.1080/23249935.2023.2264949","url":null,"abstract":"<div><div>Recent studies have shown the successful implementation of classical model-based approaches (e.g. macroscopic traffic flow modelling) and data-driven approaches (e.g. machine learning – ML) to model freeway traffic patterns, while both have their limitations. Even though model-based approaches could depict real-world traffic dynamics, they could potentially lead to inaccurate estimations due to traffic fluctuations and uncertainties. In data-driven models, the acquisition of sufficient high-quality data is required to ensure the model performance. However, many transportation applications often suffer from data shortage and noises. To overcome those limitations, this study aims to introduce and evaluate a new model, named as physics-guided machine learning (PGML), that integrates the classical traffic flow model (TFM) with the machine learning technique. This PGML model leverages the output of a traffic flow model along with observational features to generate estimations using a neural network framework. More specifically, it applies physics-guided loss functions in the learning objective of neural networks to ensure that the model not only consists with the training set but also shows lower errors on the known physics of the unlabelled set. To illustrate the effectiveness of the PGML, this study implements empirical studies with a real-world dataset collected from a stretch of I-15 freeway in Utah. Experimental study results show that the proposed PGML model could outperform the other compatible methods, including calibrated traffic flow models, pure machine learning methods, and physics unguided machine learning (PUML).</div></div>","PeriodicalId":48871,"journal":{"name":"Transportmetrica A-Transport Science","volume":"21 2","pages":"Pages 1-28"},"PeriodicalIF":3.6,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135569703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-04DOI: 10.1080/23249935.2023.2253474
Jiangbo (Gabe) Yu , Michael F. Hyland
High-quality strategic planning of autonomous mobility-on-demand (AMOD) systems is critical for the success of the subsequent phases of AMOD system implementation. To assist in strategic AMOD planning, we propose a dynamic and flexible flow-based model of an AMOD system. The proposed model is computationally fast while capturing the state transitions of two coordinated flows (i.e. co-flows): the AMOD service fleet vehicles and AMOD customers. Capturing important quantity dynamics and conservations through a system of ordinary differential equations, the model can economically respond to a large number and a wide range of scenario-testing requests. The paper illustrates the model efficacy through a basic example and a more realistic case study. The case study envisions replacing Manhattan's existing taxi service with a hypothetical AMOD system. The results show that even a simple co-flow model can robustly predict the systemwide AMOD dynamics and support the strategic planning of AMOD systems.
{"title":"Coordinated flow model for strategic planning of autonomous mobility-on-demand systems","authors":"Jiangbo (Gabe) Yu , Michael F. Hyland","doi":"10.1080/23249935.2023.2253474","DOIUrl":"10.1080/23249935.2023.2253474","url":null,"abstract":"<div><div>High-quality strategic planning of autonomous mobility-on-demand (AMOD) systems is critical for the success of the subsequent phases of AMOD system implementation. To assist in strategic AMOD planning, we propose a dynamic and flexible flow-based model of an AMOD system. The proposed model is computationally fast while capturing the state transitions of two coordinated flows (i.e. co-flows): the AMOD service fleet vehicles and AMOD customers. Capturing important quantity dynamics and conservations through a system of ordinary differential equations, the model can economically respond to a large number and a wide range of scenario-testing requests. The paper illustrates the model efficacy through a basic example and a more realistic case study. The case study envisions replacing Manhattan's existing taxi service with a hypothetical AMOD system. The results show that even a simple co-flow model can robustly predict the systemwide AMOD dynamics and support the strategic planning of AMOD systems.</div></div>","PeriodicalId":48871,"journal":{"name":"Transportmetrica A-Transport Science","volume":"21 2","pages":"Pages 1-39"},"PeriodicalIF":3.6,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42002401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-04DOI: 10.1080/23249935.2023.2243344
Zheyi Tan , Lu Zhen , Zhiyuan Yang , Lilan Liu , Tianyi Fan
This research paper delves into the intricate task of redistributing and dispatching emergency vehicles across multiple periods, while considering the unpredictable occurrence time and locations of traffic accidents. To address this challenge, we propose a two-stage stochastic programming model aimed at minimising the expected penalty cost in the face of various random scenarios. In the first stage, we determine a baseline schedule for redistributing the emergency vehicle fleets across multiple periods. In the second stage, we strategically dispatch the vehicle fleets to address traffic accidents in each scenario. To tackle this model, we employ a solution method based on variable neighbourhood search. We conduct numerical experiments and provide a real-world example to validate the effectiveness of the proposed model. Furthermore, we perform sensitivity analysis to extract managerial implications that can potentially enhance accident rescue efforts.
{"title":"Multi-period emergency vehicle fleet redistribution and dispatching","authors":"Zheyi Tan , Lu Zhen , Zhiyuan Yang , Lilan Liu , Tianyi Fan","doi":"10.1080/23249935.2023.2243344","DOIUrl":"10.1080/23249935.2023.2243344","url":null,"abstract":"<div><div>This research paper delves into the intricate task of redistributing and dispatching emergency vehicles across multiple periods, while considering the unpredictable occurrence time and locations of traffic accidents. To address this challenge, we propose a two-stage stochastic programming model aimed at minimising the expected penalty cost in the face of various random scenarios. In the first stage, we determine a baseline schedule for redistributing the emergency vehicle fleets across multiple periods. In the second stage, we strategically dispatch the vehicle fleets to address traffic accidents in each scenario. To tackle this model, we employ a solution method based on variable neighbourhood search. We conduct numerical experiments and provide a real-world example to validate the effectiveness of the proposed model. Furthermore, we perform sensitivity analysis to extract managerial implications that can potentially enhance accident rescue efforts.</div></div>","PeriodicalId":48871,"journal":{"name":"Transportmetrica A-Transport Science","volume":"21 2","pages":"Pages 1-33"},"PeriodicalIF":3.6,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45393936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-04DOI: 10.1080/23249935.2023.2249118
Luuk Brederode , Lotte Gerards , Luc Wismans , Adam Pel , Serge Hoogendoorn
To improve the accuracy of large-scale strategic transport models in congested conditions, this paper presents a straightforward extension of a static capacity-constrained traffic assignment model into a semi-dynamic version. The semi-dynamic model is more accurate than its static counterpart as it relaxes the empty network assumption, but, unlike its dynamic counterpart, maintains the stability and scalability properties required for application in large-scale strategic transport model systems. Applications show that, contrary to static models, semi-dynamic queue sizes and delays are very similar to dynamic outcomes, whereas only the congestion patterns differ due to the omission of spillback. The static and semi-dynamic models are able to reach user equilibrium conditions, whereas the dynamic model cannot. On a real-world transport model, the static model omits up to 76% of collective losses. It is therefore very likely that the empty network assumption influences (policy) decisions based on static model outcomes.
{"title":"Extension of a static into a semi-dynamic traffic assignment model with strict capacity constraints","authors":"Luuk Brederode , Lotte Gerards , Luc Wismans , Adam Pel , Serge Hoogendoorn","doi":"10.1080/23249935.2023.2249118","DOIUrl":"10.1080/23249935.2023.2249118","url":null,"abstract":"<div><div>To improve the accuracy of large-scale strategic transport models in congested conditions, this paper presents a straightforward extension of a static capacity-constrained traffic assignment model into a semi-dynamic version. The semi-dynamic model is more accurate than its static counterpart as it relaxes the empty network assumption, but, unlike its dynamic counterpart, maintains the stability and scalability properties required for application in large-scale strategic transport model systems. Applications show that, contrary to static models, semi-dynamic queue sizes and delays are very similar to dynamic outcomes, whereas only the congestion patterns differ due to the omission of spillback. The static and semi-dynamic models are able to reach user equilibrium conditions, whereas the dynamic model cannot. On a real-world transport model, the static model omits up to 76% of collective losses. It is therefore very likely that the empty network assumption influences (policy) decisions based on static model outcomes.</div></div>","PeriodicalId":48871,"journal":{"name":"Transportmetrica A-Transport Science","volume":"21 2","pages":"Pages 1-34"},"PeriodicalIF":3.6,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41314066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-05-04DOI: 10.1080/23249935.2023.2258996
Reza Mahmoudi , Saeid Saidi , S. C. Wirasinghe
This study investigates the often overlooked impact of on-board crowding on operational and user costs in public transit systems, specifically within a many-to-many bus transit line with varying demand patterns. While previous research has used mathematical programming for similar problems, this paper employs analytical approaches to offer deeper insights and address fundamental questions. First, we propose an approach to determine optimal bus capacities, factoring in in-vehicle crowding costs, assuming a fixed headway. Second, we explore the optimal dispatching policy for buses with fixed capacities, considering crowding costs. Third, we optimize both headway and vehicle capacity simultaneously. Our findings reveal that optimal vehicle capacity correlates with average passenger trip length and the square root of crowding-discomfort costs, especially when crowding increases linearly with load factor. When both headway and capacity are variable, smaller vehicles with shorter headways are favored, particularly in moderate-demand scenarios, especially with cost-effective staff models like autonomous fleets.
{"title":"Optimal vehicle capacity and dispatching policy considering crowding in public bus transit services","authors":"Reza Mahmoudi , Saeid Saidi , S. C. Wirasinghe","doi":"10.1080/23249935.2023.2258996","DOIUrl":"10.1080/23249935.2023.2258996","url":null,"abstract":"<div><div>This study investigates the often overlooked impact of on-board crowding on operational and user costs in public transit systems, specifically within a many-to-many bus transit line with varying demand patterns. While previous research has used mathematical programming for similar problems, this paper employs analytical approaches to offer deeper insights and address fundamental questions. First, we propose an approach to determine optimal bus capacities, factoring in in-vehicle crowding costs, assuming a fixed headway. Second, we explore the optimal dispatching policy for buses with fixed capacities, considering crowding costs. Third, we optimize both headway and vehicle capacity simultaneously. Our findings reveal that optimal vehicle capacity correlates with average passenger trip length and the square root of crowding-discomfort costs, especially when crowding increases linearly with load factor. When both headway and capacity are variable, smaller vehicles with shorter headways are favored, particularly in moderate-demand scenarios, especially with cost-effective staff models like autonomous fleets.</div></div>","PeriodicalId":48871,"journal":{"name":"Transportmetrica A-Transport Science","volume":"21 2","pages":"Pages 1-25"},"PeriodicalIF":3.6,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136235685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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