Pub Date : 2023-11-02DOI: 10.1177/03611981231206160
Fecri Karanki, Siew Hoon Lim
Airports are vital to economic development, the connectivity of people and services, and the movement of goods. Moreover, airports are critical infrastructure for the COVID-19 response. In this study, we attempt to examine the impacts of the COVID-19 pandemic on U.S. airports’ outputs. Specifically, our analysis focuses on the impact on output with respect to airport size, legacy carriers’ hubs, and multi-airport systems. Using the data on 59 U.S. hub airports in 2019 and 2020 and a stochastic frontier analysis with the difference-in-differences method, we find that large hub airports faced a sharper decline in their operations compared with medium hub airports; airports serving as a major hub to the three legacy carriers experienced larger output declines possibly as a result of their greater exposure to international markets; there is no significant difference in output decreases between airports in a multi-airport system and standalone airports. Regardless of the pandemic impact, large airports, airports serving as a hub of the legacy carriers, and airports belonging to a multi-airport system are on average more efficient than their respective counterparts. The initial impact of the pandemic on airports’ output sheds light on the likely structural changes in demand that airports will face in the future.
{"title":"Role of U.S. Airports’ Attributes in the Output Response to the COVID-19 Pandemic: A Stochastic Frontier Analysis with the Difference-in-Differences Method","authors":"Fecri Karanki, Siew Hoon Lim","doi":"10.1177/03611981231206160","DOIUrl":"https://doi.org/10.1177/03611981231206160","url":null,"abstract":"Airports are vital to economic development, the connectivity of people and services, and the movement of goods. Moreover, airports are critical infrastructure for the COVID-19 response. In this study, we attempt to examine the impacts of the COVID-19 pandemic on U.S. airports’ outputs. Specifically, our analysis focuses on the impact on output with respect to airport size, legacy carriers’ hubs, and multi-airport systems. Using the data on 59 U.S. hub airports in 2019 and 2020 and a stochastic frontier analysis with the difference-in-differences method, we find that large hub airports faced a sharper decline in their operations compared with medium hub airports; airports serving as a major hub to the three legacy carriers experienced larger output declines possibly as a result of their greater exposure to international markets; there is no significant difference in output decreases between airports in a multi-airport system and standalone airports. Regardless of the pandemic impact, large airports, airports serving as a hub of the legacy carriers, and airports belonging to a multi-airport system are on average more efficient than their respective counterparts. The initial impact of the pandemic on airports’ output sheds light on the likely structural changes in demand that airports will face in the future.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"16 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135972952","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}
Pub Date : 2023-10-31DOI: 10.1177/03611981231203225
Jianrong Liu, Yating Wei, Xutong Zhu, Ziyang Shi
The likelihood of pedestrians exhibiting aberrant walking behaviors and being involved in traffic collisions increases substantially if they are distracted while walking because of using their mobile phones. To reduce the frequency with which pedestrians use their phones while walking, a detailed analysis of the elements that influence this behavior is required. This research studied people’s behavior and behavioral intentions to use mobile phones while walking, using an expanded version of the theory of planned behavior. Four hundred sixty-three college students completed an online survey that assessed attitudes and behaviors related to mobile phone use. The results showed that attitude, perceived behavioral control, mobile phone addiction, crash history, and prototype similarity significantly affected behavioral intentions, whereas subjective norms, descriptive norms, perceived risk, and prototype favorability did not. In addition, behavioral intentions, perceived behavioral control, mobile phone addiction, and crash history had significant impacts on behavior, whereas perceived risk did not. The results from this study could be utilized to develop interventions to reduce the frequency with which college students use their mobile phones while walking, which is essential for improving road safety.
{"title":"Psychological Factors Influencing College Students’ Mobile Phone Use While Walking","authors":"Jianrong Liu, Yating Wei, Xutong Zhu, Ziyang Shi","doi":"10.1177/03611981231203225","DOIUrl":"https://doi.org/10.1177/03611981231203225","url":null,"abstract":"The likelihood of pedestrians exhibiting aberrant walking behaviors and being involved in traffic collisions increases substantially if they are distracted while walking because of using their mobile phones. To reduce the frequency with which pedestrians use their phones while walking, a detailed analysis of the elements that influence this behavior is required. This research studied people’s behavior and behavioral intentions to use mobile phones while walking, using an expanded version of the theory of planned behavior. Four hundred sixty-three college students completed an online survey that assessed attitudes and behaviors related to mobile phone use. The results showed that attitude, perceived behavioral control, mobile phone addiction, crash history, and prototype similarity significantly affected behavioral intentions, whereas subjective norms, descriptive norms, perceived risk, and prototype favorability did not. In addition, behavioral intentions, perceived behavioral control, mobile phone addiction, and crash history had significant impacts on behavior, whereas perceived risk did not. The results from this study could be utilized to develop interventions to reduce the frequency with which college students use their mobile phones while walking, which is essential for improving road safety.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"2011 30","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135813294","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}
Pub Date : 2023-10-31DOI: 10.1177/03611981231203220
Arka Dey, Sanhita Das
The compact sizes, lack of available physical protection, and complex maneuvering patterns of motorized two-wheeler (MTW) riders make them more vulnerable to crash risks and accidents. Considering the increased vulnerability of MTWs in dense urban mixed traffic environments, a proper evaluation and modeling of their lateral movement decisions and driving style can enhance safety associated with the riders and augment the reliability of the existing microsimulation models. Utilizing trajectory data of a six-lane divided urban arterial, the current study attempts to investigate the lateral movement (lateral shift) tendency of MTWs, addressing different influential variables that may affect riders’ decisions and describing how this choice is affected by prevailing traffic conditions. Based on several driving style parameters, such as change in speed, change in angular position, and longitudinal gap maintained with rear vehicles, this study further contributes to the existing literature by proposing a new index for identifying the driving style of riders during the lateral shifting process. Modeling results of a multinomial logit model indicated the importance of considering longitudinal and lateral gaps, vehicle speeds, and lateral fluctuations made by the subject MTW in the past trajectories in modeling the lateral shift decisions of riders. Considering the number of lateral fluctuations as an indicator of MTWs’ driving style, a new “aggressiveness index” is defined and, accordingly, a modeling approach is proposed to classify aggressive and non-aggressive driving styles of the riders. The results suggest that the history of past trajectories of the subject MTW during lateral shifting should be considered, and consideration of a non-linear relationship among the parameters can result in a better classification of driving style of MTW riders.
{"title":"Model for Predicting Lateral Shifts and Driving Style of Motorized Two-Wheelers","authors":"Arka Dey, Sanhita Das","doi":"10.1177/03611981231203220","DOIUrl":"https://doi.org/10.1177/03611981231203220","url":null,"abstract":"The compact sizes, lack of available physical protection, and complex maneuvering patterns of motorized two-wheeler (MTW) riders make them more vulnerable to crash risks and accidents. Considering the increased vulnerability of MTWs in dense urban mixed traffic environments, a proper evaluation and modeling of their lateral movement decisions and driving style can enhance safety associated with the riders and augment the reliability of the existing microsimulation models. Utilizing trajectory data of a six-lane divided urban arterial, the current study attempts to investigate the lateral movement (lateral shift) tendency of MTWs, addressing different influential variables that may affect riders’ decisions and describing how this choice is affected by prevailing traffic conditions. Based on several driving style parameters, such as change in speed, change in angular position, and longitudinal gap maintained with rear vehicles, this study further contributes to the existing literature by proposing a new index for identifying the driving style of riders during the lateral shifting process. Modeling results of a multinomial logit model indicated the importance of considering longitudinal and lateral gaps, vehicle speeds, and lateral fluctuations made by the subject MTW in the past trajectories in modeling the lateral shift decisions of riders. Considering the number of lateral fluctuations as an indicator of MTWs’ driving style, a new “aggressiveness index” is defined and, accordingly, a modeling approach is proposed to classify aggressive and non-aggressive driving styles of the riders. The results suggest that the history of past trajectories of the subject MTW during lateral shifting should be considered, and consideration of a non-linear relationship among the parameters can result in a better classification of driving style of MTW riders.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"23 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135870007","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}
Pub Date : 2023-10-31DOI: 10.1177/03611981231172505
Junia Compostella, Kailai Wang, Xiatian Iogansen, Giovanni Circella
This study examines changes in online and in-store grocery shopping in California during the COVID-19 pandemic. We analyzed survey data from before the pandemic (pre-February 2020) and during the first wave (March-June 2020). Our findings indicate an increase in online grocery purchases among consumerist individuals, while financially conservative individuals and those facing financial struggles showed a decrease. People bought more items per purchase in stores, visited stores less frequently, and transitioned from dining out to cooking at home. Those who enjoy driving and being physically active continued visiting stores more often. Social media use and health concerns influenced shopping patterns. Sociodemographic factors such as household income and race also impacted these changes.
{"title":"Trips to the Grocery Store and Online Grocery Shopping: A Comparison of Individual Behaviors before and during the First Wave of the COVID-19 Pandemic","authors":"Junia Compostella, Kailai Wang, Xiatian Iogansen, Giovanni Circella","doi":"10.1177/03611981231172505","DOIUrl":"https://doi.org/10.1177/03611981231172505","url":null,"abstract":"This study examines changes in online and in-store grocery shopping in California during the COVID-19 pandemic. We analyzed survey data from before the pandemic (pre-February 2020) and during the first wave (March-June 2020). Our findings indicate an increase in online grocery purchases among consumerist individuals, while financially conservative individuals and those facing financial struggles showed a decrease. People bought more items per purchase in stores, visited stores less frequently, and transitioned from dining out to cooking at home. Those who enjoy driving and being physically active continued visiting stores more often. Social media use and health concerns influenced shopping patterns. Sociodemographic factors such as household income and race also impacted these changes.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135870949","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}
Pub Date : 2023-10-31DOI: 10.1177/03611981231184244
Lanyue Tang, Duo Zhang, Yu Han, Aohui Fu, He Zhang, Ye Tian, Lishengsa Yue, Di Wang, Jian Sun
Microscopic traffic simulation is vital to assess the performances of various traffic operation and management schemes. Microscopic traffic simulation is usually not parameter-free, and it relies on independent parameters to predict traffic evolution. Thus, parameter calibration is indispensable to conveying trustworthy simulation results. Heuristic algorithms are widely used for parameter calibration. Its logic is for achieving iterative optimization through continuous trial-and-error simulations. This process is time-consuming and usually takes several hours, making the calibration unable to meet the requirements of speed and efficiency. In recent years, parallel computing technology has been gradually applied in the engineering realm, which makes rapid calibration possible. Following the three steps of parallel framework selection, algorithm bottleneck identification, and subtask load balancing, this paper designs and implements the parallelization of genetic algorithm and particle swarm optimization (PSO) calibration algorithms. Finally, the proposed parallel framework is applied to simulation parameter calibration of a section of a 5 km long highway in Australia, and the effectiveness of parallel computing is evaluated from the two dimensions of reduction in calibration computational time and scalability. The results show that the proposed parallel calibration algorithm can shorten the 5 h calibration process to less than 1 h, reducing the calibration time by 80%. The parallel PSO calibration algorithm has better scalability, and its acceleration effect is better when more processors are used.
{"title":"Parallel-Computing-Based Calibration for Microscopic Traffic Simulation Model","authors":"Lanyue Tang, Duo Zhang, Yu Han, Aohui Fu, He Zhang, Ye Tian, Lishengsa Yue, Di Wang, Jian Sun","doi":"10.1177/03611981231184244","DOIUrl":"https://doi.org/10.1177/03611981231184244","url":null,"abstract":"Microscopic traffic simulation is vital to assess the performances of various traffic operation and management schemes. Microscopic traffic simulation is usually not parameter-free, and it relies on independent parameters to predict traffic evolution. Thus, parameter calibration is indispensable to conveying trustworthy simulation results. Heuristic algorithms are widely used for parameter calibration. Its logic is for achieving iterative optimization through continuous trial-and-error simulations. This process is time-consuming and usually takes several hours, making the calibration unable to meet the requirements of speed and efficiency. In recent years, parallel computing technology has been gradually applied in the engineering realm, which makes rapid calibration possible. Following the three steps of parallel framework selection, algorithm bottleneck identification, and subtask load balancing, this paper designs and implements the parallelization of genetic algorithm and particle swarm optimization (PSO) calibration algorithms. Finally, the proposed parallel framework is applied to simulation parameter calibration of a section of a 5 km long highway in Australia, and the effectiveness of parallel computing is evaluated from the two dimensions of reduction in calibration computational time and scalability. The results show that the proposed parallel calibration algorithm can shorten the 5 h calibration process to less than 1 h, reducing the calibration time by 80%. The parallel PSO calibration algorithm has better scalability, and its acceleration effect is better when more processors are used.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"53 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135870277","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}
Pub Date : 2023-10-31DOI: 10.1177/03611981231201110
Steffen Coenen, Daniel Malarkey, Don MacKenzie
Advances in battery-powered electric motor systems, lightweight materials, and aircraft design have resulted in the development of new battery-electric aircraft that could gradually replace conventional fuel-powered aircraft for certain use cases in the coming years. In the face of tight climate action goals and large airport hubs facing capacity constraints, electric aircraft at regional airports could help respond to increased regional travel demands. Charging these aircraft may be a significant new load on the electric grid serving airports. In this paper, to understand these load impacts, we develop a framework for estimating future energy (annual MWh) and power (average and peak MW) demand for charging battery-electric aircraft at regional airports. We apply our modeling framework to two mid-size case study airports in Washington, U.S: Paine Field/Snohomish County Airport and Grant County International Airport. Our method has three parts: assumptions on flight operations growth, technical feasibility to serve these flights with electric aircraft, and actual adoption of electric aircraft to serve feasible trips. The results reveal that, while electricity demand could rise substantially over time, during the first decade of adoption utility companies are expected to be able to serve the energy and power needs of electric aviation with available capacity at existing substations close to the airports in our case studies.
{"title":"Estimating Electrical Energy and Capacity Demand for Regional Electric Flight Operations at Two Mid-Size Airports in Washington, U.S","authors":"Steffen Coenen, Daniel Malarkey, Don MacKenzie","doi":"10.1177/03611981231201110","DOIUrl":"https://doi.org/10.1177/03611981231201110","url":null,"abstract":"Advances in battery-powered electric motor systems, lightweight materials, and aircraft design have resulted in the development of new battery-electric aircraft that could gradually replace conventional fuel-powered aircraft for certain use cases in the coming years. In the face of tight climate action goals and large airport hubs facing capacity constraints, electric aircraft at regional airports could help respond to increased regional travel demands. Charging these aircraft may be a significant new load on the electric grid serving airports. In this paper, to understand these load impacts, we develop a framework for estimating future energy (annual MWh) and power (average and peak MW) demand for charging battery-electric aircraft at regional airports. We apply our modeling framework to two mid-size case study airports in Washington, U.S: Paine Field/Snohomish County Airport and Grant County International Airport. Our method has three parts: assumptions on flight operations growth, technical feasibility to serve these flights with electric aircraft, and actual adoption of electric aircraft to serve feasible trips. The results reveal that, while electricity demand could rise substantially over time, during the first decade of adoption utility companies are expected to be able to serve the energy and power needs of electric aviation with available capacity at existing substations close to the airports in our case studies.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"249 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135813473","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}
Pub Date : 2023-10-31DOI: 10.1177/03611981231203221
Zhaoqing Wang, Xinle Gong, Xueyun Li, Xingyu Li, Jin Huang
The allocation of controlling and driving authority is an important and difficult aspect of human–machine shared steering control (SSC). This paper addresses the SSC problem in high-speed emergency obstacle avoidance scenarios. A parallel SSC framework containing a dynamic driving authority allocation model and a path tracking controller is developed, where the human driver and controller can control the vehicle simultaneously. First, fuzzy logic is adopted in the SSC framework to actively adjust the driving authority between the human driver and the controller. The driver steering state and path tracking error are considered to reduce the negative impact of a driver’s mis-operation and weaken any human–machine conflict. Subsequently, the path tracking controller in the proposed SSC system is designed based on a nonlinear vehicle lateral model to improve the accuracy of the controller, particularly when the vehicle is facing large lateral acceleration. To address the nonlinear control problem, the Udwadia–Kalaba approach is employed and the Lyapunov stability of the controller is proved. Finally, the effectiveness of the proposed SSC system is proved through simulation results, which show that the vehicle has excellent path tracking performance in high-speed obstacle avoidance scenarios. In addition, the system can resolve the human–machine conflict problem.
{"title":"Human–Machine Shared Steering Control Under High-Speed Emergency Obstacle Avoidance Scenarios","authors":"Zhaoqing Wang, Xinle Gong, Xueyun Li, Xingyu Li, Jin Huang","doi":"10.1177/03611981231203221","DOIUrl":"https://doi.org/10.1177/03611981231203221","url":null,"abstract":"The allocation of controlling and driving authority is an important and difficult aspect of human–machine shared steering control (SSC). This paper addresses the SSC problem in high-speed emergency obstacle avoidance scenarios. A parallel SSC framework containing a dynamic driving authority allocation model and a path tracking controller is developed, where the human driver and controller can control the vehicle simultaneously. First, fuzzy logic is adopted in the SSC framework to actively adjust the driving authority between the human driver and the controller. The driver steering state and path tracking error are considered to reduce the negative impact of a driver’s mis-operation and weaken any human–machine conflict. Subsequently, the path tracking controller in the proposed SSC system is designed based on a nonlinear vehicle lateral model to improve the accuracy of the controller, particularly when the vehicle is facing large lateral acceleration. To address the nonlinear control problem, the Udwadia–Kalaba approach is employed and the Lyapunov stability of the controller is proved. Finally, the effectiveness of the proposed SSC system is proved through simulation results, which show that the vehicle has excellent path tracking performance in high-speed obstacle avoidance scenarios. In addition, the system can resolve the human–machine conflict problem.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"10 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135870630","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}
Pub Date : 2023-10-27DOI: 10.1177/03611981231196149
Merve Seher Cebeci, Rodrigo Javier Tapia, Ali Nadi, Michiel de Bok, Lóránt Tavasszy
Crowdsourced shipping or crowdshipping is a promising solution to sustainable parcel delivery, owing to the potential to consolidate freight trips with preexisting passenger trips. Previous literature focuses on these consolidation benefits but does not address the possibility of new activity generation in crowdshipping. In this study, we investigate the willingness of private persons to accept shipments based on a newly generated home-based trip. We compare this to the choices of occasional carriers who build on the daily home–work commute to deliver parcels. Two stated preference experiments are conducted and a multinomial logit choice model and a latent class choice model are employed. These allow us to provide values of time of the occasional carriers, as an original contribution to the literature. The results show that commute-based carrier values of time are higher than those of home-based carriers. Concerning the trip generating power of crowdshipping, we find that low-income groups have a relatively high propensity to generate a home-based pickup and delivery trip. Finally, parcel lockers as delivery points positively influence acceptance of crowdshipping requests, as they allow for more flexibility in delivery times. Together, these results support the notion that crowdshipping can act as a potential trip generator in households.
{"title":"Does Crowdshipping of Parcels Generate New Passenger Trips? Evidence from the Netherlands","authors":"Merve Seher Cebeci, Rodrigo Javier Tapia, Ali Nadi, Michiel de Bok, Lóránt Tavasszy","doi":"10.1177/03611981231196149","DOIUrl":"https://doi.org/10.1177/03611981231196149","url":null,"abstract":"Crowdsourced shipping or crowdshipping is a promising solution to sustainable parcel delivery, owing to the potential to consolidate freight trips with preexisting passenger trips. Previous literature focuses on these consolidation benefits but does not address the possibility of new activity generation in crowdshipping. In this study, we investigate the willingness of private persons to accept shipments based on a newly generated home-based trip. We compare this to the choices of occasional carriers who build on the daily home–work commute to deliver parcels. Two stated preference experiments are conducted and a multinomial logit choice model and a latent class choice model are employed. These allow us to provide values of time of the occasional carriers, as an original contribution to the literature. The results show that commute-based carrier values of time are higher than those of home-based carriers. Concerning the trip generating power of crowdshipping, we find that low-income groups have a relatively high propensity to generate a home-based pickup and delivery trip. Finally, parcel lockers as delivery points positively influence acceptance of crowdshipping requests, as they allow for more flexibility in delivery times. Together, these results support the notion that crowdshipping can act as a potential trip generator in households.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"12 12","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136261688","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}
Pub Date : 2023-10-27DOI: 10.1177/03611981231203229
Jiawen Wang, Chenxi Hu, Jing Zhao, Lingzhi Zhang, Yin Han
Platoon merging control of autonomous vehicles driving in a platoon formation can improve traffic efficiency. However, current platoon merging control approaches primarily rely on rules, making it challenging to achieve optimal control. In this study, we propose a platoon merging control approach based on a deep Q-network (DQN). First, we specify the state and action of the vehicle and establish a set of reward functions to ensure safe driving. Then, the DQN algorithm is used to train a neural network suitable for merging the controls of connected and automated vehicles (CAVs) to continuously approach the state-value function. Finally, we compare the proposed approach with a rule-based (RB) vehicle merging approach using a MATLAB simulation. In particular, CAVs are driven simultaneously using the two approaches in a random environment. The simulation results show that the proposed DQN-based vehicle merging approach requires less merging travel time and fewer vehicle lane change times than the RB approach. Additionally, merging can result in improved capacity in medium and high traffic densities compared with no-merging: the higher the CAV penetration rate, the larger the improvement. We verify the effectiveness of the proposed approach for different initial conditions. We suggest that the proposed method is a safe and robust method for CAV platoon merging, and that it can be applied to increase the capacity of freeways and roads.
{"title":"Deep Q-Network-Enabled Platoon Merging Approach for Autonomous Vehicles","authors":"Jiawen Wang, Chenxi Hu, Jing Zhao, Lingzhi Zhang, Yin Han","doi":"10.1177/03611981231203229","DOIUrl":"https://doi.org/10.1177/03611981231203229","url":null,"abstract":"Platoon merging control of autonomous vehicles driving in a platoon formation can improve traffic efficiency. However, current platoon merging control approaches primarily rely on rules, making it challenging to achieve optimal control. In this study, we propose a platoon merging control approach based on a deep Q-network (DQN). First, we specify the state and action of the vehicle and establish a set of reward functions to ensure safe driving. Then, the DQN algorithm is used to train a neural network suitable for merging the controls of connected and automated vehicles (CAVs) to continuously approach the state-value function. Finally, we compare the proposed approach with a rule-based (RB) vehicle merging approach using a MATLAB simulation. In particular, CAVs are driven simultaneously using the two approaches in a random environment. The simulation results show that the proposed DQN-based vehicle merging approach requires less merging travel time and fewer vehicle lane change times than the RB approach. Additionally, merging can result in improved capacity in medium and high traffic densities compared with no-merging: the higher the CAV penetration rate, the larger the improvement. We verify the effectiveness of the proposed approach for different initial conditions. We suggest that the proposed method is a safe and robust method for CAV platoon merging, and that it can be applied to increase the capacity of freeways and roads.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"22 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136316403","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}
Pub Date : 2023-10-27DOI: 10.1177/03611981231203230
Murad Y. Abu-Farsakh, Md Habibur Rahman, Navid Jafari
Subsurface soil conditions usually involve special site variability that cannot be ignored for design and analysis. Therefore, the effect of site variability on associated soil properties should be assessed using gathered field data, such as soil boring data collected from discrete locations. In this study, six spatial interpolation techniques, the ordinary kriging (OK), simple kriging (SK), universal kriging (UK), inverse distance weight (IDW), spline, and natural neighbor (NaN) were evaluated to assess the best prediction strategy for considering site variability. The efficacy of these methods was tested at four soil boring sites. Boring profiles were generated using the different techniques at specified locations for each site, and the created data were compared with the measured soil boring profiles. For each location, the best-fit line of measured versus predicted undrained shear strength (S u ) or standard penetration test (SPT) number, mean bias factor (λ), coefficient of effectiveness (COE), root mean square error (RMSE), and coefficient of variation (COV), were calculated and used to assess the various interpolation methods. The findings of this study demonstrated the ability of these spatial interpolations to produce precise soil boring data. The slope of best-fit line of measured/generated S u and SPT ranged from 0.89 to 0.99. The best-performing interpolation methods (in order) are: IDW, OK/UK, and SK methods. The results show that the COVs between the measured and synthetic soil boring data at the selected points are significantly lower than the COVs between the measured soil boring profiles for the entire site.
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