This study discusses the optimal link toll,which maximizes social surplus under a user equilibrium condition,with imperfect substitution assumption for route choice in a transportation network with many nodes and link...This study discusses the optimal link toll,which maximizes social surplus under a user equilibrium condition,with imperfect substitution assumption for route choice in a transportation network with many nodes and links,as well as taking into account the welfare cost of funds procurement.In contrast to previous studies,this study formulates optimal link tolls,taking into account the marginal cost of public funds(MCF),which is the marginal welfare loss of taxpayers due to a marginal tax raise.The formula for optimal tolls on links is derived from the following conditions.One is MCF classified into two,not taking into account funding(MCF equal to-1)and pricing for funding(MCF does not equal-1).Another is tolls classified into two,pricing on all links(full link pricing),and pricing on a specific link(partial link pricing).Following the above conditions,this study succeeds in deriving the formula for optimal tolls on a full network with many links and nodes.Furthermore,this study indicates two calculation methods:one is to solve analytically or numerically for when the functional form of link flow demand is known.When the functional form is unknown,such as a perfect substitution case,it is necessary to carry out iteration until convergence:with the traffic assignment given the price level and with a change in price level based on the traffic assignment.展开更多
Pedestrian level of service(PLOS)is an important measure of performance in the analysis of existing pedestrian crosswalk conditions.Many researchers have developed PLOS models based on pedestrian delay,turning vehicle...Pedestrian level of service(PLOS)is an important measure of performance in the analysis of existing pedestrian crosswalk conditions.Many researchers have developed PLOS models based on pedestrian delay,turning vehicle effect,etc.,using the conventional regression method.However,these factors may not effectively reflect the pedestrians'perception of safety while crossing the crosswalk.The conventional regression method has failed to estimate accurate PLOS because of the primary assumption of an arbitrary probability distribution and vagueness in the input data.Moreover,PLOS categories in existing studies are based on rigid threshold values and the boundaries that are not well defined.Therefore,it is an important attempt to develop a PLOS model with respect to pedestrian safety,convenience,and efficiency at signalized intersections.For this purpose,a video-graphic and user perception surveys were conducted at selected nine signalized intersections in Mumbai,India.The data such as pedestrian,traffic,and geometric characteristics were extracted,and significant variables were identified using Pearson correlation analysis.A consistent and statistically calibrated PLOS model was developed using fuzzy linear regression analysis.PLOS was categorized into six levels(A–F)based on the predicted user perception score,and threshold values for each level were estimated using the fuzzy c-means clustering technique.The developed PLOS model and threshold values were validated with the fieldobserved data.Statistical performance tests were conducted and the results provided more accurate and reliable solutions.In conclusion,this study provides a feasible alternative to measure pedestrian perception-based level of service at signalized intersections.The developed PLOS model and threshold values would be useful for planning and designing pedestrian facilities and also in evaluating and improving the existing conditions of pedestrian facilities at signalized intersections.展开更多
Impact of flood depth on traffic volume in two different zones of the Bangkok road network was investigated using traffic data obtained from probe vehicle trajectories.A Macroscopic Fundamental Diagram(MFD)was utilize...Impact of flood depth on traffic volume in two different zones of the Bangkok road network was investigated using traffic data obtained from probe vehicle trajectories.A Macroscopic Fundamental Diagram(MFD)was utilized to compare traffic flow rates across two road network zones in the city for a variety of flood depths,namely 0-5 cm,5-10 cm,10-15 cm,15-30 cm,and more than 30 cm.Results of empirical analysis over an observation period of one year as 2019 showed that flood depths had a strong correlation with the MFD parameters of free-flow speed,maximum flow,and traffic jam density.In particular,road floods greatly reduced average maximum flow across the inner city road network in Bangkok.Road floods had a significant impact on traffic characteristics of urban road networks.展开更多
Urban Air Mobility(UAM)is an emerging transportation system that aims at revolutionizing urban mobility through the deployment of small electric vertical takeoff and landing(eVTOL)aircraft.The development of UAM is la...Urban Air Mobility(UAM)is an emerging transportation system that aims at revolutionizing urban mobility through the deployment of small electric vertical takeoff and landing(eVTOL)aircraft.The development of UAM is largely driven by advances in Intelligent Technology(IT).This review article provides an overview of the UAM system and discusses the application of IT in UAM.Major challenges facing UAM are also identified,and an outlook on the future of this promising transportation system is presented.Our main conclusions suggest that IT is a fundamental driver of UAM,enabling a range of applications such as air traffic management and autonomous drone control.However,the UAM system is facing a number of challenges,including eVTOL technology,system integration issues,and noise pollution.Despite these challenges,the future of UAM appears promising;as a disruptive transportation mode,UAM is expected to play an important role in addressing the growing demand of urban transportation in the coming decades.展开更多
Cooperative and Adaptive Cruise Control(CACC)is widely focused to enhance driving fuel-efficiency by maintaining a close following gap.The ecology of CACC could be further enhanced by adapting to the rolling terrain.H...Cooperative and Adaptive Cruise Control(CACC)is widely focused to enhance driving fuel-efficiency by maintaining a close following gap.The ecology of CACC could be further enhanced by adapting to the rolling terrain.However,current studies cannot ensure both planning optimality and computational efficiency.Firstly,current studies are mostly formulated on the conventional time domain.These time domain based methods cannot ensure planning optimality for space-varying road slopes.Secondly,fuel consumption models are non-linear and hard to solve efficiently.Hence,this paper proposes a space domain based Ecological-CACC(Eco-CACC)controller.It is formulated into a nonlinear optimal control problem with the objective of optimizing global fuel consumptions.Furthermore,a differential dynamic programming-based solving method is developed to ensure real-time computational efficiency.Simulation results have shown that the proposed Eco-CACC controller can improve the average fuel saving by 37.67%at collector road and about 17.30%at major arterial.The string stability of the proposed method has been theoretically proven and experimentally validated.展开更多
An appropriate understanding and accurate estimation of zonal freight production(FP)and attraction(FA)volume is one of the most important topics and the initial step in developing the origin and destination(OD)matrix....An appropriate understanding and accurate estimation of zonal freight production(FP)and attraction(FA)volume is one of the most important topics and the initial step in developing the origin and destination(OD)matrix.In general,zonal FP and FA are difficult to be obtained as observed data,particularly in developing countries,owing to the lack of large-scale freight surveys.Thus,several proxy indicators are often used for estimating FP and FA,such as the gross regional product(GRP),population,and the number of establishments.However,these indicators do not often estimate the zonal FP and FA accurately and are even not available readily.The nighttime light intensity(NLI)data that is human-induced light emission data and one of the open alternative data,possibly improves the accuracy of FP and FA estimation.However,few studies have examined the relationship between NLI and FP/FA.Therefore,the objectives of this study are to examine whether NLI can be a significant indicator for estimating zonal FP and FA relative to other socio-economic indicators and to examine the types of NLIs that can accurately estimate the FP and FA through a case study in Japan.As a result of the analysis,NLI data are identified as a significant variable for the estimation of FP and FA among various socio-economic variables.Although some of the indicators related to secondary industries provide higher accuracy,NLI exhibits better estimates than the popular indicators such as GRP and population.In addition,we propose three types of total NLI that multiply the unit NLI by the zonal area and this generates higher accuracy of unit NLI,the average light intensity of all pixels in a zone.We have also found that the use of habitable area for the estimation of total NLI provides the highest accuracy among the four types of NLIs including unit NLI.Through the analysis,NLI data is sufficiently applicable for estimating zonal FP and FA,relative to other important socio-economic indicators,although space transferability should be examined in other study areas.These findings could help estimating FP/FA particularly in countries and regions with limited statistical data available.展开更多
Traffic noise is one of the major sources of noise pollution in metropolitan regions causing various health hazards （e.g., long-term sleep disturbance, increase in blood pressure, physical tension, etc.）. In this re...Traffic noise is one of the major sources of noise pollution in metropolitan regions causing various health hazards （e.g., long-term sleep disturbance, increase in blood pressure, physical tension, etc.）. In this research, noise prediction models, which can measure the noise level experienced by the commuters while driving or traveling by motorized vehicles in the Mumbai Metropolitan Region, India, were developed. These models were developed by conducting a comprehensive study of various factors （e.g., vehicle speed, traffic volume and road characteristics, etc.） affecting the levels of concentration of noise. A widespread data collection was done by conducting road trips of total length of 403.80 km via different modes of transport, such as air-conditioned （A/C） car, non A/G car, bus and intermediate public transport （i.e., traditional 3-wheeler autos）. Multiple regression analyses were per- formed to develop a functional relation between equivalent noise levels experienced by passengers while traveling （which was considered as a dependent variable） and explana- tory variables such as traffic characteristics, vehicle class, vehicle speed, various other location characteristics, etc. Noise levels are generally higher in the vicinity of intersections and signalized junctions. Independent data sets （for each mode of transport） were used to validate the developed models. It was noted that maximum differences between observed and estimated values from the model were within the range of ±7.8% of the observed value.展开更多
文摘This study discusses the optimal link toll,which maximizes social surplus under a user equilibrium condition,with imperfect substitution assumption for route choice in a transportation network with many nodes and links,as well as taking into account the welfare cost of funds procurement.In contrast to previous studies,this study formulates optimal link tolls,taking into account the marginal cost of public funds(MCF),which is the marginal welfare loss of taxpayers due to a marginal tax raise.The formula for optimal tolls on links is derived from the following conditions.One is MCF classified into two,not taking into account funding(MCF equal to-1)and pricing for funding(MCF does not equal-1).Another is tolls classified into two,pricing on all links(full link pricing),and pricing on a specific link(partial link pricing).Following the above conditions,this study succeeds in deriving the formula for optimal tolls on a full network with many links and nodes.Furthermore,this study indicates two calculation methods:one is to solve analytically or numerically for when the functional form of link flow demand is known.When the functional form is unknown,such as a perfect substitution case,it is necessary to carry out iteration until convergence:with the traffic assignment given the price level and with a change in price level based on the traffic assignment.
文摘Pedestrian level of service(PLOS)is an important measure of performance in the analysis of existing pedestrian crosswalk conditions.Many researchers have developed PLOS models based on pedestrian delay,turning vehicle effect,etc.,using the conventional regression method.However,these factors may not effectively reflect the pedestrians'perception of safety while crossing the crosswalk.The conventional regression method has failed to estimate accurate PLOS because of the primary assumption of an arbitrary probability distribution and vagueness in the input data.Moreover,PLOS categories in existing studies are based on rigid threshold values and the boundaries that are not well defined.Therefore,it is an important attempt to develop a PLOS model with respect to pedestrian safety,convenience,and efficiency at signalized intersections.For this purpose,a video-graphic and user perception surveys were conducted at selected nine signalized intersections in Mumbai,India.The data such as pedestrian,traffic,and geometric characteristics were extracted,and significant variables were identified using Pearson correlation analysis.A consistent and statistically calibrated PLOS model was developed using fuzzy linear regression analysis.PLOS was categorized into six levels(A–F)based on the predicted user perception score,and threshold values for each level were estimated using the fuzzy c-means clustering technique.The developed PLOS model and threshold values were validated with the fieldobserved data.Statistical performance tests were conducted and the results provided more accurate and reliable solutions.In conclusion,this study provides a feasible alternative to measure pedestrian perception-based level of service at signalized intersections.The developed PLOS model and threshold values would be useful for planning and designing pedestrian facilities and also in evaluating and improving the existing conditions of pedestrian facilities at signalized intersections.
文摘Impact of flood depth on traffic volume in two different zones of the Bangkok road network was investigated using traffic data obtained from probe vehicle trajectories.A Macroscopic Fundamental Diagram(MFD)was utilized to compare traffic flow rates across two road network zones in the city for a variety of flood depths,namely 0-5 cm,5-10 cm,10-15 cm,15-30 cm,and more than 30 cm.Results of empirical analysis over an observation period of one year as 2019 showed that flood depths had a strong correlation with the MFD parameters of free-flow speed,maximum flow,and traffic jam density.In particular,road floods greatly reduced average maximum flow across the inner city road network in Bangkok.Road floods had a significant impact on traffic characteristics of urban road networks.
文摘Urban Air Mobility(UAM)is an emerging transportation system that aims at revolutionizing urban mobility through the deployment of small electric vertical takeoff and landing(eVTOL)aircraft.The development of UAM is largely driven by advances in Intelligent Technology(IT).This review article provides an overview of the UAM system and discusses the application of IT in UAM.Major challenges facing UAM are also identified,and an outlook on the future of this promising transportation system is presented.Our main conclusions suggest that IT is a fundamental driver of UAM,enabling a range of applications such as air traffic management and autonomous drone control.However,the UAM system is facing a number of challenges,including eVTOL technology,system integration issues,and noise pollution.Despite these challenges,the future of UAM appears promising;as a disruptive transportation mode,UAM is expected to play an important role in addressing the growing demand of urban transportation in the coming decades.
基金partially supported by National Key R&D Program of China(No.2022YFF0604905)National Natural Science Foundation of China(No.52302412 and 52372317)+5 种基金Shanghai Automotive Industry Science and Technology Development Foundation(No.2213)Tongji Zhongte Chair Professor Foundation(No.000000375-2018082)Shanghai Sailing Program(No.23YF1449600)Shanghai Post-doctoral Excellence Program(No.2022571)China Postdoctoral Science Foundation(No.2022M722405)Xiaomi Young Talents Program,and the Science Fund of State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle(No.32215011).
文摘Cooperative and Adaptive Cruise Control(CACC)is widely focused to enhance driving fuel-efficiency by maintaining a close following gap.The ecology of CACC could be further enhanced by adapting to the rolling terrain.However,current studies cannot ensure both planning optimality and computational efficiency.Firstly,current studies are mostly formulated on the conventional time domain.These time domain based methods cannot ensure planning optimality for space-varying road slopes.Secondly,fuel consumption models are non-linear and hard to solve efficiently.Hence,this paper proposes a space domain based Ecological-CACC(Eco-CACC)controller.It is formulated into a nonlinear optimal control problem with the objective of optimizing global fuel consumptions.Furthermore,a differential dynamic programming-based solving method is developed to ensure real-time computational efficiency.Simulation results have shown that the proposed Eco-CACC controller can improve the average fuel saving by 37.67%at collector road and about 17.30%at major arterial.The string stability of the proposed method has been theoretically proven and experimentally validated.
基金supported by The Kurata Grants:The Hitachi Global Foundation,grant number 1445.
文摘An appropriate understanding and accurate estimation of zonal freight production(FP)and attraction(FA)volume is one of the most important topics and the initial step in developing the origin and destination(OD)matrix.In general,zonal FP and FA are difficult to be obtained as observed data,particularly in developing countries,owing to the lack of large-scale freight surveys.Thus,several proxy indicators are often used for estimating FP and FA,such as the gross regional product(GRP),population,and the number of establishments.However,these indicators do not often estimate the zonal FP and FA accurately and are even not available readily.The nighttime light intensity(NLI)data that is human-induced light emission data and one of the open alternative data,possibly improves the accuracy of FP and FA estimation.However,few studies have examined the relationship between NLI and FP/FA.Therefore,the objectives of this study are to examine whether NLI can be a significant indicator for estimating zonal FP and FA relative to other socio-economic indicators and to examine the types of NLIs that can accurately estimate the FP and FA through a case study in Japan.As a result of the analysis,NLI data are identified as a significant variable for the estimation of FP and FA among various socio-economic variables.Although some of the indicators related to secondary industries provide higher accuracy,NLI exhibits better estimates than the popular indicators such as GRP and population.In addition,we propose three types of total NLI that multiply the unit NLI by the zonal area and this generates higher accuracy of unit NLI,the average light intensity of all pixels in a zone.We have also found that the use of habitable area for the estimation of total NLI provides the highest accuracy among the four types of NLIs including unit NLI.Through the analysis,NLI data is sufficiently applicable for estimating zonal FP and FA,relative to other important socio-economic indicators,although space transferability should be examined in other study areas.These findings could help estimating FP/FA particularly in countries and regions with limited statistical data available.
文摘Traffic noise is one of the major sources of noise pollution in metropolitan regions causing various health hazards （e.g., long-term sleep disturbance, increase in blood pressure, physical tension, etc.）. In this research, noise prediction models, which can measure the noise level experienced by the commuters while driving or traveling by motorized vehicles in the Mumbai Metropolitan Region, India, were developed. These models were developed by conducting a comprehensive study of various factors （e.g., vehicle speed, traffic volume and road characteristics, etc.） affecting the levels of concentration of noise. A widespread data collection was done by conducting road trips of total length of 403.80 km via different modes of transport, such as air-conditioned （A/C） car, non A/G car, bus and intermediate public transport （i.e., traditional 3-wheeler autos）. Multiple regression analyses were per- formed to develop a functional relation between equivalent noise levels experienced by passengers while traveling （which was considered as a dependent variable） and explana- tory variables such as traffic characteristics, vehicle class, vehicle speed, various other location characteristics, etc. Noise levels are generally higher in the vicinity of intersections and signalized junctions. Independent data sets （for each mode of transport） were used to validate the developed models. It was noted that maximum differences between observed and estimated values from the model were within the range of ±7.8% of the observed value.
