Strategic transportation network models are often used as support tools in the framework of decisions to be taken at the policy level, such as the Trans-European Network projects. These models are mostly setup using a...Strategic transportation network models are often used as support tools in the framework of decisions to be taken at the policy level, such as the Trans-European Network projects. These models are mostly setup using aggregated or limited data. If their calibration is regularly mentioned in the literature, their validation is barely discussed. In this paper, several modal choice model specifications that make only use of explanatory variables available at the network level are described and applied to a large scale case. A validation exercise is performed at three levels of aggregation. The paper is designed from a strategic transport planning perspective, and does not present new modal choice formulations or assignment procedures. Its main added value is the focus on calibration and validation considerations. Despite the limited explanatory information used, the global performance of the best models can be considered as satisfactory. However, the quality of the models varies from mode to mode, the use of railway transport being the most difficult to predict without more specific input.展开更多
I<span style="font-family:Verdana;">n Ghana, freight transport is growing continuously every year due to its location and business processes. However, road transport carries 86% of frei</span><...I<span style="font-family:Verdana;">n Ghana, freight transport is growing continuously every year due to its location and business processes. However, road transport carries 86% of frei</span><span style="font-family:Verdana;">ght despite its numerous negative impacts. Hence, the government has invested in rail transport, with 70% of its capacity is for freight transport in her busy freight transport corridor (eastern transport regions of Ghana). Thus, awareness of criteria considered when deciding on freight transport becomes vital. Hence, this study aims to improve the understanding of the fa</span><span style="font-family:Verdana;">ctors of freight transport mode selection in Ghana from the decision-</span><span style="font-family:Verdana;">making process by identifying criteria that affect their decisions on mode transportation. The combination of Fuzzy AHP and Topsis is used to find the weights and suggest suitable alternatives for the decision-makers in the Eastern transport regions of Ghana. The result of this study shows that the criteria to consider when selecting freight transport mode in the regions are prioritized in other of Transport cost (0.6544), transport Time factors (0.2562), reliability, and flexibility (0.0605), and security, Risk of damage and lose factors (0.0287). Additionally, the suitable mode(s) of transportation in the stated corridor is owned truck carrier transport compared to the railroad, road-barge, and Contracted Carrier, thus, in descending order. The results provide organizations to prioritize these factors when deciding to select freight transport mode. At the same time, the government must remove some inputs that result in high transport cost</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;">, enforce</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">policies, and invest in the appropriate mode.</span>展开更多
This study presents a descriptive and prescriptive analysis of rail service subsidies for China Railway Express(CRE)in the China-Europe freight transportation market.The analysis is conducted by advanced mathematical ...This study presents a descriptive and prescriptive analysis of rail service subsidies for China Railway Express(CRE)in the China-Europe freight transportation market.The analysis is conducted by advanced mathematical modeling and programming methods.Specifically,we implemented a multicommodity multimodal freight transportation network equilib-rium model that can be used for predicting the commodity-specific mode-route cargo flow pattern and hence for assessing the effectiveness and limitations of the current CRE subsidy scheme.To properly quantify the impact of subsidies on individual shippers’decision mak-ing,the model explicitly characterizes individual shippers’mode-route choice behavior and takes into account shipping cost,transit time,capacity-induced congestion surcharge,and unobserved transportation impedances as shippers’disutility.The solution of the net-work equilibrium model resorts to a disaggregate simplicial decomposition(DSD)algo-rithm within the well-known Lagrangian relaxation framework.A bi-level network-based subsidy optimization model is constructed,in which the upper level aims at mini-mizing the sum of revenue loss and congestion charge,and the lower level is the aforemen-tioned freight transportation network equilibrium model.A tabu search procedure is proposed and implemented to derive the solution of the bi-level model.The above models and algorithms are then applied to the China-Europe containerized freight transportation network,which comprises all China-Europe liner shipping lines,all CRE service lines,and the highway networks in China and Europe.The evaluation and optimization results show that the current subsidy scheme creates an imbalanced capacity utilization pattern across CRE service lines while an optimized line-specific subsidy solution can yield note-worthy improvements in the service utilization and economic efficiency of CRE.展开更多
The amount of perishable products transported via the existing intermodal freight networks has significantly increased over the last years. Perishable products tend to decay due to a wide range of external factors. Su...The amount of perishable products transported via the existing intermodal freight networks has significantly increased over the last years. Perishable products tend to decay due to a wide range of external factors. Supply chain operations mismanagement causes waste of substantial volumes of perishable products every year. The heretofore proposed mathematical models optimize certain supply chain processes and reduce decay of perishable products, but primarily deal with local production, inventory, distribution, and retailing of perishable products. However, significant quantities of perishable products are delivered from different continents, which shall increase the total transportation time and decay potential of perishable products as compared to local deliveries. This paper proposes a novel optimization model to design the intermodal freight network for both local and long-haul deliveries of perishable products. The objective of the model aims to minimize the total cost associated with transportation and decay of perishable products. A set of piecewise approximations are applied to linearize the non-linear decay function for each perishable product type. CPLEX is used to solve the problem. Comprehensive numerical experiments are conducted using the intermodal freight network for import of the seafood perishable products to the United States to draw important managerial insights. Results demonstrate that increasing product decay cost may significantly change the design of intermodal freight network for transport of perishable products, cause modal shifts and affect the total transportation time and associated costs.展开更多
Multimodal freight transportation emerges as the go-to strategy for cost-effectively and sustainably moving goods over long distances. In a multimodal freight system, where a single contract includes various transport...Multimodal freight transportation emerges as the go-to strategy for cost-effectively and sustainably moving goods over long distances. In a multimodal freight system, where a single contract includes various transportation methods, businesses aiming for economic success must make well-informed decisions about which modes of transport to use. These decisions prioritize secure deliveries, competitive cost advantages, and the minimization of environmental footprints associated with transportation-related pollution. Within the dynamic landscape of logistics innovation, various multicriteria decision-making (MCDM) approaches empower businesses to evaluate freight transport options thoroughly. In this study, we utilize a case study to demonstrate the application of the Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) algorithm for MCDM decision-making in freight mode selection. We further enhance the TOPSIS framework by integrating the entropy weight coefficient method. This enhancement aids in assigning precise weights to each criterion involved in mode selection, leading to a more reliable decision-making process. The proposed model provides cost-effective and timely deliveries, minimizing environmental footprint and meeting consumers’ needs. Our findings reveal that freight carbon footprint is the primary concern, followed by freight cost, time sensitivity, and service reliability. The study identifies the combination of Rail/Truck as the ideal mode of transport and containers in flat cars (COFC) as the next best option for the selected case. The proposed algorithm, incorporating the enhanced TOPSIS framework, benefits companies navigating the complexities of multimodal transport. It empowers making more strategic and informed transportation decisions. This demonstration will be increasingly valuable as companies navigate the ever-growing trade within the global supply chains.展开更多
Modal choice models applied to interregional or international freight transportation network models are often based on rather coarse origin-destination matrices, containing annual transported tonnages between (sub)reg...Modal choice models applied to interregional or international freight transportation network models are often based on rather coarse origin-destination matrices, containing annual transported tonnages between (sub)regions, for instance. Generally, only basic (sometimes constructed) independent variables (transportation costs or transit times) are used because other variables such as shipment sizes, service frequencies, etc. are not available. Using origin-destination matrices and an assignment model, it is also possible to compute spatial accessibility measures that can further be used as additional explanatory variables. Indeed, several published studies have identified network accessibility as an important element in the mode-choice decision. This paper also shows that the inclusion of an accessibility measure in the utility functions of a logit model substantially improves the performance of a transportation network model, both in the modal choice and the assignment levels of the classical four-step model. Consequently, the assignment of the estimated modal demands results in more accurate estimated traffic on the networks. The model presented in this paper is to be considered as a proof of concept because its workflow should further be streamlined to make it easily useable by modelers.展开更多
Land transport can no longer meet the requirements.European transport can be described by these words−crowded motorways and cities,dangerous emissions,ubiquitous traffic accidents,delays,expensive railways.Solutions a...Land transport can no longer meet the requirements.European transport can be described by these words−crowded motorways and cities,dangerous emissions,ubiquitous traffic accidents,delays,expensive railways.Solutions are being sought to transfer a large part of passengers and especially freight transport to(high-speed)rail,and efforts are moving towards electromobility,car-sharing,5G-connectivity,autonomous driving,MaaS(Mobility as a Service)-coordinated transport or hyperloop-type solutions.However,all these solutions have additional challenges and limitations.Solutions are not being searched where they really exist-in the mutual adaptation of road and rail vehicles and their deep cooperation.The ComplexTrans project shows that simply adapting the dimensions and functions of road and rail vehicles can eliminate(or at least significantly reduce)all the problems of existing land transport.The main features of the ComplexTrans system are sufficient parking spaces,reduction of urban and non-urban congestion,electric vehicles with unlimited range and cheaper than standard cars,cheaper and more accessible battery charging,“autonomous ride”,solving the overlap between passenger and freight rail transport and making it self-financing,transferring intercity freight transport to rail,replacing part of continental air transport and many others.The cost-effective and clustered individual transport and individualised public transport of the ComplexTrans system also bring very significant reductions in the risk of transmission of covid-19 and other contagious diseases during transport.展开更多
Large goods transported in railway are kinds of special goods and they are very important in national construction. In order to transport safely, loading and reinforcing schemes must be made first. How to design a rea...Large goods transported in railway are kinds of special goods and they are very important in national construction. In order to transport safely, loading and reinforcing schemes must be made first. How to design a reasonable scheme will be affected by many factors. This paper presents the characteristic of the large goods, summarizes the process of designing a loading and reinforcing scheme of large good, then probes the factors of affecting the loading and reinforcing scheme and gives a detail analysis. It’s considered that those out-of-gauge and overweight degree of goods, center-of- gravity height of a loaded wagon, position of center-of-gravity of goods, type of wagon for using, reinforcement material and reinforcement method, transport expense and transport organization could affect a scheme in the aspects of safety, economy, rapidity and convenience. This conclusion will instruct and help to make a good scheme.展开更多
This paper discusses the disaggregation of the Federal Highway Administration’s Freight Analysis Framework(FAF)database(version 3.0)on freight origin-destination data and the development of linear regression equation...This paper discusses the disaggregation of the Federal Highway Administration’s Freight Analysis Framework(FAF)database(version 3.0)on freight origin-destination data and the development of linear regression equations to describe the relationships between commodity-based freight trip productions/attractions to specific economic variables.Instead of generating a production/attraction equation for each commodity,commodities are grouped in certain ways to simplify model development and application.We consider three grouping methods and two model selection criteria(with and without intercepts),which are compared in terms of goodness of fit with two data sets(FAF versions 2.0 and 3.0).Furthermore,the freight generation models are validated using county-level economic data in California and applied to predict year 2015 commodity outputs.The results of this study can help city,county,metropolitan and state level planning agencies develop their own customized freight demand generation models without performing costly large-scale surveys.展开更多
The expansion of e-commerce and the sharing economy has paved the way for crowdshipping as an innovative approach to addressing last-mile delivery challenges.Previous studies and implementations have predominantly con...The expansion of e-commerce and the sharing economy has paved the way for crowdshipping as an innovative approach to addressing last-mile delivery challenges.Previous studies and implementations have predominantly concentrated on private vehicle-based crowdshipping,which may lead to increased traffic congestion and emissions due to additional trips made specifically for deliveries.To circumvent these possible adverse effects,this paper explores a public transport(PT)-based crowdshipping concept as a complementary solution to the traditional parcel delivery systems.In this model,PT users leverage their routine journeys to perform delivery tasks.We propose a methodology that includes a parcel locker location model and a vehicle routing model to analyze the effect of PT-based crowdshipping.Notably,the parcel locker location model aids in planning a PT-based crowdshipping network and identifying obstacles to its development.A case study conducted in the central district of Copenhagen utilizing real-world data assesses the effects of PT-based crowdshipping.The findings suggest that PT-based crowdshipping can decrease the total kilometers traveled by vehicles,the overall working hours of drivers,and the number of vans required for last-mile deliveries,thereby alleviating urban traffic congestion and environmental pollution.Nevertheless,the growth of PT-based crowdshipping may be limited by the availability of crowdshippers,indicating that initiatives to increase the number of crowdshippers are essential.展开更多
Urban transportation is a major element of sustainable urban development and a key factor affecting the health of urban residents.It influences public health through noise,air pollution,social isolation,inactive modes...Urban transportation is a major element of sustainable urban development and a key factor affecting the health of urban residents.It influences public health through noise,air pollution,social isolation,inactive modes of transportation,and sedentary behaviors.This paper reviews literature related to urban transportation and health from two perspectives:travel behavior and environmental impact.It focuses on passenger transportation and freight transportation to analyze their respective negative environmental externalities,such as noise,environmental pollution,and accidents.After the literature review,the paper identifies the main deficiencies in urban transportation research aiming to build healthy cities,and proposes measures and suggestions for future research.展开更多
The loading and unloading operations carried out by transport and logistics operators have a strong impact on city mobility if they are not performed correctly.If loading/unloading bays,i.e.,delivery bays(DB),are not ...The loading and unloading operations carried out by transport and logistics operators have a strong impact on city mobility if they are not performed correctly.If loading/unloading bays,i.e.,delivery bays(DB),are not available for freight vehicle operations,operators may opt to double park or park on the sidewalk where there is no strong enforcement of these laws,with significant impact on congestion.This paper proposes a methodology for verifying and designing the number of delivery bays needed for freight vehicles for not interfere with cars or pedestrians.The methodology consists of two stages:in the first stage,an initial estimation is made using queueing theory.Subsequently,in the second stage,using such tentative scenario,in order to take into account the system stochasticity involving different entities,a discrete event simulation is performed to more realistically verify and upgrade(if necessary)the number of delivery bays to obtain the expected outcomes.The methodology was applied in the inner area of Santander(Spain).The study area was subdivided into 29 zones where the methodology was applied individually.The results indicated that none of these zones currently have an optimal number of delivery bays to satisfy demand.In some zones,there is an excess of delivery bays,although in most of them,there is a deficit which can cause significant impacts on traffic.The method proposed can be an effective tool to be used by city planners for improving freight operations in urban areas limiting the negative impacts produced in terms of internal and external costs.展开更多
With new sources of big data,it is increasingly possible to practically implement advanced freight forecasting models including activity-based and truck touring models.Such models improve upon traditional trip-based a...With new sources of big data,it is increasingly possible to practically implement advanced freight forecasting models including activity-based and truck touring models.Such models improve upon traditional trip-based approaches by capturing freight behaviors sensitive to transportation policy and infrastructure changes.A persistent challenge with the use of big data in this context is the ability to generalize a set of representative behaviors to serve as the basis for model calibration and validation from anonymized data depicting the complex behaviors of the population.To address this challenge,we present a two-stage methodology to extract unique and representative freight activity patterns from passively collected truck Global Positioning System(GPS)data.The first stage involved a heuristicbased approach to derive a set of stop and trip characteristics from large-streams of GPS pings.The second stage employed data mining and machine learning techniques to discern common freight activity patterns from the set of defined features.The resulting activity pattern profiles,defined as chains of activities and their trajectories over time and space,allow us to maintain the anonymity of the trucks included in the GPS dataset while providing high-resolution travel profiles-a necessary condition for most data sharing agreements between public agencies and private data providers.These activity patterns serve as the critical,and currently missing,data needed to calibrate and validate advanced freight forecasting models.With more advanced forecasting models reflective of observed freight behaviors,we will be able to evaluate a wider spectrum of policy and infrastructure scenarios more accurately.展开更多
文摘Strategic transportation network models are often used as support tools in the framework of decisions to be taken at the policy level, such as the Trans-European Network projects. These models are mostly setup using aggregated or limited data. If their calibration is regularly mentioned in the literature, their validation is barely discussed. In this paper, several modal choice model specifications that make only use of explanatory variables available at the network level are described and applied to a large scale case. A validation exercise is performed at three levels of aggregation. The paper is designed from a strategic transport planning perspective, and does not present new modal choice formulations or assignment procedures. Its main added value is the focus on calibration and validation considerations. Despite the limited explanatory information used, the global performance of the best models can be considered as satisfactory. However, the quality of the models varies from mode to mode, the use of railway transport being the most difficult to predict without more specific input.
文摘I<span style="font-family:Verdana;">n Ghana, freight transport is growing continuously every year due to its location and business processes. However, road transport carries 86% of frei</span><span style="font-family:Verdana;">ght despite its numerous negative impacts. Hence, the government has invested in rail transport, with 70% of its capacity is for freight transport in her busy freight transport corridor (eastern transport regions of Ghana). Thus, awareness of criteria considered when deciding on freight transport becomes vital. Hence, this study aims to improve the understanding of the fa</span><span style="font-family:Verdana;">ctors of freight transport mode selection in Ghana from the decision-</span><span style="font-family:Verdana;">making process by identifying criteria that affect their decisions on mode transportation. The combination of Fuzzy AHP and Topsis is used to find the weights and suggest suitable alternatives for the decision-makers in the Eastern transport regions of Ghana. The result of this study shows that the criteria to consider when selecting freight transport mode in the regions are prioritized in other of Transport cost (0.6544), transport Time factors (0.2562), reliability, and flexibility (0.0605), and security, Risk of damage and lose factors (0.0287). Additionally, the suitable mode(s) of transportation in the stated corridor is owned truck carrier transport compared to the railroad, road-barge, and Contracted Carrier, thus, in descending order. The results provide organizations to prioritize these factors when deciding to select freight transport mode. At the same time, the government must remove some inputs that result in high transport cost</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;">, enforce</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">policies, and invest in the appropriate mode.</span>
基金sponsored by National Natural Science Foundation of China(Nos.72171175 and 71771150)the Open Foundation of Key Laboratory of Transport Industry of Comprehensive Transportation Theory,and the Fundamental Research Funds of Central Universities at Tongji University.
文摘This study presents a descriptive and prescriptive analysis of rail service subsidies for China Railway Express(CRE)in the China-Europe freight transportation market.The analysis is conducted by advanced mathematical modeling and programming methods.Specifically,we implemented a multicommodity multimodal freight transportation network equilib-rium model that can be used for predicting the commodity-specific mode-route cargo flow pattern and hence for assessing the effectiveness and limitations of the current CRE subsidy scheme.To properly quantify the impact of subsidies on individual shippers’decision mak-ing,the model explicitly characterizes individual shippers’mode-route choice behavior and takes into account shipping cost,transit time,capacity-induced congestion surcharge,and unobserved transportation impedances as shippers’disutility.The solution of the net-work equilibrium model resorts to a disaggregate simplicial decomposition(DSD)algo-rithm within the well-known Lagrangian relaxation framework.A bi-level network-based subsidy optimization model is constructed,in which the upper level aims at mini-mizing the sum of revenue loss and congestion charge,and the lower level is the aforemen-tioned freight transportation network equilibrium model.A tabu search procedure is proposed and implemented to derive the solution of the bi-level model.The above models and algorithms are then applied to the China-Europe containerized freight transportation network,which comprises all China-Europe liner shipping lines,all CRE service lines,and the highway networks in China and Europe.The evaluation and optimization results show that the current subsidy scheme creates an imbalanced capacity utilization pattern across CRE service lines while an optimized line-specific subsidy solution can yield note-worthy improvements in the service utilization and economic efficiency of CRE.
文摘The amount of perishable products transported via the existing intermodal freight networks has significantly increased over the last years. Perishable products tend to decay due to a wide range of external factors. Supply chain operations mismanagement causes waste of substantial volumes of perishable products every year. The heretofore proposed mathematical models optimize certain supply chain processes and reduce decay of perishable products, but primarily deal with local production, inventory, distribution, and retailing of perishable products. However, significant quantities of perishable products are delivered from different continents, which shall increase the total transportation time and decay potential of perishable products as compared to local deliveries. This paper proposes a novel optimization model to design the intermodal freight network for both local and long-haul deliveries of perishable products. The objective of the model aims to minimize the total cost associated with transportation and decay of perishable products. A set of piecewise approximations are applied to linearize the non-linear decay function for each perishable product type. CPLEX is used to solve the problem. Comprehensive numerical experiments are conducted using the intermodal freight network for import of the seafood perishable products to the United States to draw important managerial insights. Results demonstrate that increasing product decay cost may significantly change the design of intermodal freight network for transport of perishable products, cause modal shifts and affect the total transportation time and associated costs.
文摘Multimodal freight transportation emerges as the go-to strategy for cost-effectively and sustainably moving goods over long distances. In a multimodal freight system, where a single contract includes various transportation methods, businesses aiming for economic success must make well-informed decisions about which modes of transport to use. These decisions prioritize secure deliveries, competitive cost advantages, and the minimization of environmental footprints associated with transportation-related pollution. Within the dynamic landscape of logistics innovation, various multicriteria decision-making (MCDM) approaches empower businesses to evaluate freight transport options thoroughly. In this study, we utilize a case study to demonstrate the application of the Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS) algorithm for MCDM decision-making in freight mode selection. We further enhance the TOPSIS framework by integrating the entropy weight coefficient method. This enhancement aids in assigning precise weights to each criterion involved in mode selection, leading to a more reliable decision-making process. The proposed model provides cost-effective and timely deliveries, minimizing environmental footprint and meeting consumers’ needs. Our findings reveal that freight carbon footprint is the primary concern, followed by freight cost, time sensitivity, and service reliability. The study identifies the combination of Rail/Truck as the ideal mode of transport and containers in flat cars (COFC) as the next best option for the selected case. The proposed algorithm, incorporating the enhanced TOPSIS framework, benefits companies navigating the complexities of multimodal transport. It empowers making more strategic and informed transportation decisions. This demonstration will be increasingly valuable as companies navigate the ever-growing trade within the global supply chains.
文摘Modal choice models applied to interregional or international freight transportation network models are often based on rather coarse origin-destination matrices, containing annual transported tonnages between (sub)regions, for instance. Generally, only basic (sometimes constructed) independent variables (transportation costs or transit times) are used because other variables such as shipment sizes, service frequencies, etc. are not available. Using origin-destination matrices and an assignment model, it is also possible to compute spatial accessibility measures that can further be used as additional explanatory variables. Indeed, several published studies have identified network accessibility as an important element in the mode-choice decision. This paper also shows that the inclusion of an accessibility measure in the utility functions of a logit model substantially improves the performance of a transportation network model, both in the modal choice and the assignment levels of the classical four-step model. Consequently, the assignment of the estimated modal demands results in more accurate estimated traffic on the networks. The model presented in this paper is to be considered as a proof of concept because its workflow should further be streamlined to make it easily useable by modelers.
基金This research is partly supported by project SGS-2019-001The 3-D visualisations were prepared by students of University of West Bohemia or by professional designers.
文摘Land transport can no longer meet the requirements.European transport can be described by these words−crowded motorways and cities,dangerous emissions,ubiquitous traffic accidents,delays,expensive railways.Solutions are being sought to transfer a large part of passengers and especially freight transport to(high-speed)rail,and efforts are moving towards electromobility,car-sharing,5G-connectivity,autonomous driving,MaaS(Mobility as a Service)-coordinated transport or hyperloop-type solutions.However,all these solutions have additional challenges and limitations.Solutions are not being searched where they really exist-in the mutual adaptation of road and rail vehicles and their deep cooperation.The ComplexTrans project shows that simply adapting the dimensions and functions of road and rail vehicles can eliminate(or at least significantly reduce)all the problems of existing land transport.The main features of the ComplexTrans system are sufficient parking spaces,reduction of urban and non-urban congestion,electric vehicles with unlimited range and cheaper than standard cars,cheaper and more accessible battery charging,“autonomous ride”,solving the overlap between passenger and freight rail transport and making it self-financing,transferring intercity freight transport to rail,replacing part of continental air transport and many others.The cost-effective and clustered individual transport and individualised public transport of the ComplexTrans system also bring very significant reductions in the risk of transmission of covid-19 and other contagious diseases during transport.
文摘Large goods transported in railway are kinds of special goods and they are very important in national construction. In order to transport safely, loading and reinforcing schemes must be made first. How to design a reasonable scheme will be affected by many factors. This paper presents the characteristic of the large goods, summarizes the process of designing a loading and reinforcing scheme of large good, then probes the factors of affecting the loading and reinforcing scheme and gives a detail analysis. It’s considered that those out-of-gauge and overweight degree of goods, center-of- gravity height of a loaded wagon, position of center-of-gravity of goods, type of wagon for using, reinforcement material and reinforcement method, transport expense and transport organization could affect a scheme in the aspects of safety, economy, rapidity and convenience. This conclusion will instruct and help to make a good scheme.
文摘This paper discusses the disaggregation of the Federal Highway Administration’s Freight Analysis Framework(FAF)database(version 3.0)on freight origin-destination data and the development of linear regression equations to describe the relationships between commodity-based freight trip productions/attractions to specific economic variables.Instead of generating a production/attraction equation for each commodity,commodities are grouped in certain ways to simplify model development and application.We consider three grouping methods and two model selection criteria(with and without intercepts),which are compared in terms of goodness of fit with two data sets(FAF versions 2.0 and 3.0).Furthermore,the freight generation models are validated using county-level economic data in California and applied to predict year 2015 commodity outputs.The results of this study can help city,county,metropolitan and state level planning agencies develop their own customized freight demand generation models without performing costly large-scale surveys.
基金supported by the China Scholarship Council(202107940012).
文摘The expansion of e-commerce and the sharing economy has paved the way for crowdshipping as an innovative approach to addressing last-mile delivery challenges.Previous studies and implementations have predominantly concentrated on private vehicle-based crowdshipping,which may lead to increased traffic congestion and emissions due to additional trips made specifically for deliveries.To circumvent these possible adverse effects,this paper explores a public transport(PT)-based crowdshipping concept as a complementary solution to the traditional parcel delivery systems.In this model,PT users leverage their routine journeys to perform delivery tasks.We propose a methodology that includes a parcel locker location model and a vehicle routing model to analyze the effect of PT-based crowdshipping.Notably,the parcel locker location model aids in planning a PT-based crowdshipping network and identifying obstacles to its development.A case study conducted in the central district of Copenhagen utilizing real-world data assesses the effects of PT-based crowdshipping.The findings suggest that PT-based crowdshipping can decrease the total kilometers traveled by vehicles,the overall working hours of drivers,and the number of vans required for last-mile deliveries,thereby alleviating urban traffic congestion and environmental pollution.Nevertheless,the growth of PT-based crowdshipping may be limited by the availability of crowdshippers,indicating that initiatives to increase the number of crowdshippers are essential.
文摘Urban transportation is a major element of sustainable urban development and a key factor affecting the health of urban residents.It influences public health through noise,air pollution,social isolation,inactive modes of transportation,and sedentary behaviors.This paper reviews literature related to urban transportation and health from two perspectives:travel behavior and environmental impact.It focuses on passenger transportation and freight transportation to analyze their respective negative environmental externalities,such as noise,environmental pollution,and accidents.After the literature review,the paper identifies the main deficiencies in urban transportation research aiming to build healthy cities,and proposes measures and suggestions for future research.
文摘The loading and unloading operations carried out by transport and logistics operators have a strong impact on city mobility if they are not performed correctly.If loading/unloading bays,i.e.,delivery bays(DB),are not available for freight vehicle operations,operators may opt to double park or park on the sidewalk where there is no strong enforcement of these laws,with significant impact on congestion.This paper proposes a methodology for verifying and designing the number of delivery bays needed for freight vehicles for not interfere with cars or pedestrians.The methodology consists of two stages:in the first stage,an initial estimation is made using queueing theory.Subsequently,in the second stage,using such tentative scenario,in order to take into account the system stochasticity involving different entities,a discrete event simulation is performed to more realistically verify and upgrade(if necessary)the number of delivery bays to obtain the expected outcomes.The methodology was applied in the inner area of Santander(Spain).The study area was subdivided into 29 zones where the methodology was applied individually.The results indicated that none of these zones currently have an optimal number of delivery bays to satisfy demand.In some zones,there is an excess of delivery bays,although in most of them,there is a deficit which can cause significant impacts on traffic.The method proposed can be an effective tool to be used by city planners for improving freight operations in urban areas limiting the negative impacts produced in terms of internal and external costs.
文摘With new sources of big data,it is increasingly possible to practically implement advanced freight forecasting models including activity-based and truck touring models.Such models improve upon traditional trip-based approaches by capturing freight behaviors sensitive to transportation policy and infrastructure changes.A persistent challenge with the use of big data in this context is the ability to generalize a set of representative behaviors to serve as the basis for model calibration and validation from anonymized data depicting the complex behaviors of the population.To address this challenge,we present a two-stage methodology to extract unique and representative freight activity patterns from passively collected truck Global Positioning System(GPS)data.The first stage involved a heuristicbased approach to derive a set of stop and trip characteristics from large-streams of GPS pings.The second stage employed data mining and machine learning techniques to discern common freight activity patterns from the set of defined features.The resulting activity pattern profiles,defined as chains of activities and their trajectories over time and space,allow us to maintain the anonymity of the trucks included in the GPS dataset while providing high-resolution travel profiles-a necessary condition for most data sharing agreements between public agencies and private data providers.These activity patterns serve as the critical,and currently missing,data needed to calibrate and validate advanced freight forecasting models.With more advanced forecasting models reflective of observed freight behaviors,we will be able to evaluate a wider spectrum of policy and infrastructure scenarios more accurately.
