The significance of network structure indicators for the planning and management of conventional public transit is widely acknowledged.In order to improve and enrich the conventional public transit assessment system,t...The significance of network structure indicators for the planning and management of conventional public transit is widely acknowledged.In order to improve and enrich the conventional public transit assessment system,two network structure indicators are proposed.Firstly,according to the obvious defects lying in the traditional no-linear coefficient,the realistic no-linear coefficient γRNL,a modified no-linear coefficient indicator,is put forward,which takes into account the effects of barriers in a city.Secondly,to cover the gap of an indicator which can reflect the coverage homogeneity of a transit network,the length dimension LDis proposed on the basis of Fractal Theory.Finally,a case study is applied to verify the validity and practicability of the two indicators in problem diagnosis using regression analysis.The results validate that γRNLcan evaluate the detour of bus lines more reasonably than the previous no-linear coefficient because it reflects the layout of bus lines,and LDcan represent the rate of change of the network density,adding a new member to the scheme of network structure indicators for public transit.展开更多
At the beginning of the twentieth century, the United States was leading in the public transit sector, but following World War II, private automobiles became more affordable and gained popularity. Transportation infra...At the beginning of the twentieth century, the United States was leading in the public transit sector, but following World War II, private automobiles became more affordable and gained popularity. Transportation infrastructure investments that increased road capacity further facilitated the increase in automobile use at the expense of reduced public transit ridership. With the increase of dependency on automobiles and the continuing growth of private automobile ownership and use, various problems became major challenges in big cities of USA. These include traffic congestion, air pollution, road and parking infrastructure costs, energy consumption, traffic safety, fewer mobility options for the non-drivers, and a decline in the image and use of public transit. This study uses a medium sized city, Birmingham as a case study to investigate the potential of public transit to reduce automobile trips and in turn improve the overall performance of the road network by addressing the abovementioned challenges. An agent-based simulation model was developed for the Birmingham metropolitan region using the Multi-agent Transport Simulation (MATSim) platform. Three scenarios were considered with gradually increased transit ridership to identify the benefits of increased public transit. Traffic volume, network average speed, and travel times were used as performance measures for the evaluation of the designated scenarios. Results suggest that modal shifts toward public transit and reduction in travel demand for an automobile can result in improvements in speed and travel time for all users. Therefore, investments for improving transit quality and frequency of service, as well as campaigns to improve the image of public transit and make it a mode of choice for transportation users can increase transit ridership and, in turn, improve network operations, thus are deemed worthy for medium sized cities.展开更多
Based on the existing classical cellular automaton model of traffic flow,a cellular automaton traffic model with different-maximum-speed vehicles mixed on a single lane is proposed,in which public transit and harbour-...Based on the existing classical cellular automaton model of traffic flow,a cellular automaton traffic model with different-maximum-speed vehicles mixed on a single lane is proposed,in which public transit and harbour-shaped bus stops are taken into consideration.Parameters such as length of cellular automaton,operation speed and random slow mechanism are re-demarcated.A harbour-shaped bus stop is set up and the vehicle changing lane regulation is changed.Through computer simulation,the influence of occupation rate of public transit vehicles on mixed traffic flow and traffic capacity is analysed.The results show that a public transport system can ease urban traffic congestion but creates new jams at the same time,and that the influence of occupation rate of public transit vehicles on traffic capacity is considerable.To develop urban traffic,attention should be paid to the occupation rate of public transit vehicles and traffic development in a haphazard way should be strictly avoided.展开更多
In an urban-transit bus,fueled by biodiesel in Toledo,Ohio,single inhalable particle samples in October 2008 were collected and detected by scanning electron microscopy and energy dispersive X-ray spectrometry(SEM/EDS...In an urban-transit bus,fueled by biodiesel in Toledo,Ohio,single inhalable particle samples in October 2008 were collected and detected by scanning electron microscopy and energy dispersive X-ray spectrometry(SEM/EDS).Particle size analysis found bimodal distribution at 0.2 and 0.5 μm.The particle morphology was characterized by 14 different shape clusters:square,pentagon,hexagon,heptagon,octagon,nonagon,decagon,agglomerate,sphere,triangle,oblong,strip,line or stick,and unknown,by quantitative order.The square particles were common in the samples.Round and triangle particles are more,and pentagon,hexagon,heptagon,octagon,nonagon,decagon,strip,line or sticks are less.Agglomerate particles were found in abundance.The surface of most particles was coarse with a fractal edge that can provide a suitable chemical reaction bed in the polluted atmospheric environment.The three sorts of surface patterns of squares were smooth,semi-smooth,and coarse.The three sorts of square surface patterns represented the morphological characteristics of single inhalable particles in the air inside the bus in Toledo.The size and shape distribution results were compared to those obtained for a bus using ultra low sulfur diesel.展开更多
Taking public transit facilities (PTFs) is the major transport style in Hong Kong. Human exposure to indoor air pollutants may cause adverse health effects to the passengers. Exposure assessment on air pollutants is i...Taking public transit facilities (PTFs) is the major transport style in Hong Kong. Human exposure to indoor air pollutants may cause adverse health effects to the passengers. Exposure assessment on air pollutants is important for the control of human diseases caused by indoor air pollution. In this paper, the indoor PM10, CO and CO 2 levels in various PTFs, such as public bus, subway, railway and ferry in Hong Kong, were mea- sured. Combining with the time budget survey of Hong Kong population,the human exposures were calculated through Monte-Carlo simulation.展开更多
This study evaluates the operational performance of all routes of Sajha Bus Yatayat operating inside Kathmandu valley using Data Envelopment Analysis (DEA) in terms of efficiency and effectiveness score. This approach...This study evaluates the operational performance of all routes of Sajha Bus Yatayat operating inside Kathmandu valley using Data Envelopment Analysis (DEA) in terms of efficiency and effectiveness score. This approach allows us to access the relative performance of transit system in absence of historical data and research to compare with. To explore the possibility of enhancing the performance, scenarios were created for relatively underperforming routes and long route problem by changing the most important input variable and output variables accordingly with regression model where it was relevant. Partial Least Squares (PLS) regression was used to determine the most influential input variables to the output variables. DEA was conducted to access the performance of all routes under these scenarios. Underperforming routes except the longest route under the first set of scenarios, emerge to be better performing efficiently without considerable negative deviation in effectiveness. The result of second set of scenarios for long route problem suggests that the longest route’s performance can be enhanced significantly upon proper route alignment. Scenarios development and evaluation can help lead transit companies to explore the strategies to facilitate operational performance enhancement.展开更多
Public transport system has been a means of addressing transportation challenges in urban areas, such as traffic congestion, traffic jam and long travel time in cities worldwide. Transportation in Africa is unique in ...Public transport system has been a means of addressing transportation challenges in urban areas, such as traffic congestion, traffic jam and long travel time in cities worldwide. Transportation in Africa is unique in that it has the least developed public transport systems in the world, while also being one of the fastest urbanizing continents. Bus Rapid Transit being one of the public transport systems was introduced in Africa in 2008 as a means to provide solution on urban transportation challenges. Despite of public transport being the main means of transport in African developing countries, there have been a number of challenges that affects efficiency of performance of the system and makes its users uncomfortable. Therefore, the study aimed at exploring the setbacks or challenges associated with operation and performance of the BRT system in the African developing countries and address them. The study employed mixed methods research design that integrates both qualitative and quantitative data collection methods and analysis. The study findings reveal that, there is an improvement on the perspectives of the commuters on public transport after introduction of BRT system. However, some challenges such as long waiting time, passengers overcrowding during peak hours, as well as safety and security can slowly change the perspective of the commuters. Therefore, to address these challenges it is recommended to reduce the long waiting time and improve accessibility by introduction of passenger information displays (bus information system) and automated fare collection system;reduce travel time by introduction of bus priority signal;and improve safety and security by introduction of signage and CCTV Camera within the bus and bus stops.展开更多
Most of the current existing accessibility measures quantify the potential of reaching desirable opportunities across space and time.Nevertheless,these potential measurements only illus-trate the maximum possible acce...Most of the current existing accessibility measures quantify the potential of reaching desirable opportunities across space and time.Nevertheless,these potential measurements only illus-trate the maximum possible accessibility a person can have,which may not accurately measure real-world transit accessibility in urban areas.This paper introduces a novel methodology to measure positive public transit accessibility based on multi-source big public transit data such as Smart Card Data(SCD)and Global Navigation Satellite System trajectory data,which embed rich travel information and real-world spatio-temporal constraints.First,we use multi-source transit data to reconstruct trip chains,which are used to extract popular destinations.A novel transit accessibility measure is defined to account for latent trip information such as mode/route preference,opportunity attraction,and travel impedance that are difficult to capture explicitly via traditional normative measures.Finally,we produce accessibility maps to visualize time-varying and heterogeneous accessibility patterns distributed over the study region.We performed an empirical evaluation on real-world transit data collected in Shenzhen City,China,demonstrating the applicability and effectiveness of the proposed method in mapping positive transit accessibility over large metropolitan areas.The results and findings of the empirical study demonstrate that the proposed positive accessibility measure can better capture travel behavior characteristics and constraints than traditional normative measures.The measure-ment method can be used as a practical high-resolution mapping tool for transit decision makers in evaluating public transit systems,supporting strategic transit planning,and improv-ing daily transit management.展开更多
Reaching carbon neutrality will require investment on an unprecedented scale.Here we suggest that there is an underappreciated opportunity to leverage public funds to mobilize private capital in support of these aims....Reaching carbon neutrality will require investment on an unprecedented scale.Here we suggest that there is an underappreciated opportunity to leverage public funds to mobilize private capital in support of these aims.We illustrate the point using examples from public transit.Although the fuelling energy requirements of public fleets represent a small fraction of the eventual total demand across the transportation sector,the predictable and long-term nature of the refuelling profiles can reduce the financing risk.With appropriate coordination across the energy supply chain,near-term investments can be used to support scale-up of wider efforts to decarbonize the transportation sector and electric grid.We present two examples from California-one related to overnight power for battery electric bus charging and the other related to medium-scale supply chains for zero-carbon hydrogen production-to illustrate how this might be achieved.展开更多
The traditional manner to design public transportation system is to sequentially design the transit network and public bicycle network. A new public transportation system design problem that simultaneously considers b...The traditional manner to design public transportation system is to sequentially design the transit network and public bicycle network. A new public transportation system design problem that simultaneously considers both bus network design and public bicycle network design is proposed. The chemical reaction optimization(CRO) is designed to solve the problem. A shortcoming of CRO is that, when the two-molecule collisions take place, the molecules are randomly picked from the container.Hence, we improve CRO by employing different mating strategies. The computational results confirm the benefits of the mating strategies. Numerical experiments are conducted on the Sioux-Falls network. A comparison with the traditional sequential modeling framework indicates that the proposed approach has a better performance and is more robust. The practical applicability of the approach is proved by employing a real size network.展开更多
The world is trying to recover from once in the COVID-19 pandemic, which has a higher mortality rate than the common flu. However, the threat of different variants is still affecting us in a different capacity. Severa...The world is trying to recover from once in the COVID-19 pandemic, which has a higher mortality rate than the common flu. However, the threat of different variants is still affecting us in a different capacity. Several preventive measures have been adopted across the nation and the globe to avoid the spr<span style="font-family:Verdana;">ead of this virus, such as lockdown, restricted travel, social distancing guidelin</span><span style="font-family:Verdana;">es, obligatory face mask use, etc. These activities directly influenced the manag</span><span style="font-family:Verdana;">ement of social life, economy, and livelihoods. The effect of COVID-</span><span style="font-family:Verdana;">19 on the public transit industry and strategies the transit agencies adapted to continue providing the service during the pandemic has been synthesized in this pap</span><span style="font-family:Verdana;">er. As a result of the pandemic, public transit ridership decreased by abou</span><span style="font-family:Verdana;">t 70 percent for most agencies compared to pre-pandemic levels. This article also highlights the prevention of COVID-19 spread in the public transit industry using engineering solutions and advanced material science and nanotechnology solutions.</span>展开更多
基金Sponsored by the National High Technology Research and Development Program of China(Grant No.214AA110303)
文摘The significance of network structure indicators for the planning and management of conventional public transit is widely acknowledged.In order to improve and enrich the conventional public transit assessment system,two network structure indicators are proposed.Firstly,according to the obvious defects lying in the traditional no-linear coefficient,the realistic no-linear coefficient γRNL,a modified no-linear coefficient indicator,is put forward,which takes into account the effects of barriers in a city.Secondly,to cover the gap of an indicator which can reflect the coverage homogeneity of a transit network,the length dimension LDis proposed on the basis of Fractal Theory.Finally,a case study is applied to verify the validity and practicability of the two indicators in problem diagnosis using regression analysis.The results validate that γRNLcan evaluate the detour of bus lines more reasonably than the previous no-linear coefficient because it reflects the layout of bus lines,and LDcan represent the rate of change of the network density,adding a new member to the scheme of network structure indicators for public transit.
文摘At the beginning of the twentieth century, the United States was leading in the public transit sector, but following World War II, private automobiles became more affordable and gained popularity. Transportation infrastructure investments that increased road capacity further facilitated the increase in automobile use at the expense of reduced public transit ridership. With the increase of dependency on automobiles and the continuing growth of private automobile ownership and use, various problems became major challenges in big cities of USA. These include traffic congestion, air pollution, road and parking infrastructure costs, energy consumption, traffic safety, fewer mobility options for the non-drivers, and a decline in the image and use of public transit. This study uses a medium sized city, Birmingham as a case study to investigate the potential of public transit to reduce automobile trips and in turn improve the overall performance of the road network by addressing the abovementioned challenges. An agent-based simulation model was developed for the Birmingham metropolitan region using the Multi-agent Transport Simulation (MATSim) platform. Three scenarios were considered with gradually increased transit ridership to identify the benefits of increased public transit. Traffic volume, network average speed, and travel times were used as performance measures for the evaluation of the designated scenarios. Results suggest that modal shifts toward public transit and reduction in travel demand for an automobile can result in improvements in speed and travel time for all users. Therefore, investments for improving transit quality and frequency of service, as well as campaigns to improve the image of public transit and make it a mode of choice for transportation users can increase transit ridership and, in turn, improve network operations, thus are deemed worthy for medium sized cities.
基金supported by the Science and Technology Supporting Program of Gansu Province,China (Grant No 0804GKCA038)
文摘Based on the existing classical cellular automaton model of traffic flow,a cellular automaton traffic model with different-maximum-speed vehicles mixed on a single lane is proposed,in which public transit and harbour-shaped bus stops are taken into consideration.Parameters such as length of cellular automaton,operation speed and random slow mechanism are re-demarcated.A harbour-shaped bus stop is set up and the vehicle changing lane regulation is changed.Through computer simulation,the influence of occupation rate of public transit vehicles on mixed traffic flow and traffic capacity is analysed.The results show that a public transport system can ease urban traffic congestion but creates new jams at the same time,and that the influence of occupation rate of public transit vehicles on traffic capacity is considerable.To develop urban traffic,attention should be paid to the occupation rate of public transit vehicles and traffic development in a haphazard way should be strictly avoided.
文摘In an urban-transit bus,fueled by biodiesel in Toledo,Ohio,single inhalable particle samples in October 2008 were collected and detected by scanning electron microscopy and energy dispersive X-ray spectrometry(SEM/EDS).Particle size analysis found bimodal distribution at 0.2 and 0.5 μm.The particle morphology was characterized by 14 different shape clusters:square,pentagon,hexagon,heptagon,octagon,nonagon,decagon,agglomerate,sphere,triangle,oblong,strip,line or stick,and unknown,by quantitative order.The square particles were common in the samples.Round and triangle particles are more,and pentagon,hexagon,heptagon,octagon,nonagon,decagon,strip,line or sticks are less.Agglomerate particles were found in abundance.The surface of most particles was coarse with a fractal edge that can provide a suitable chemical reaction bed in the polluted atmospheric environment.The three sorts of surface patterns of squares were smooth,semi-smooth,and coarse.The three sorts of square surface patterns represented the morphological characteristics of single inhalable particles in the air inside the bus in Toledo.The size and shape distribution results were compared to those obtained for a bus using ultra low sulfur diesel.
文摘Taking public transit facilities (PTFs) is the major transport style in Hong Kong. Human exposure to indoor air pollutants may cause adverse health effects to the passengers. Exposure assessment on air pollutants is important for the control of human diseases caused by indoor air pollution. In this paper, the indoor PM10, CO and CO 2 levels in various PTFs, such as public bus, subway, railway and ferry in Hong Kong, were mea- sured. Combining with the time budget survey of Hong Kong population,the human exposures were calculated through Monte-Carlo simulation.
文摘This study evaluates the operational performance of all routes of Sajha Bus Yatayat operating inside Kathmandu valley using Data Envelopment Analysis (DEA) in terms of efficiency and effectiveness score. This approach allows us to access the relative performance of transit system in absence of historical data and research to compare with. To explore the possibility of enhancing the performance, scenarios were created for relatively underperforming routes and long route problem by changing the most important input variable and output variables accordingly with regression model where it was relevant. Partial Least Squares (PLS) regression was used to determine the most influential input variables to the output variables. DEA was conducted to access the performance of all routes under these scenarios. Underperforming routes except the longest route under the first set of scenarios, emerge to be better performing efficiently without considerable negative deviation in effectiveness. The result of second set of scenarios for long route problem suggests that the longest route’s performance can be enhanced significantly upon proper route alignment. Scenarios development and evaluation can help lead transit companies to explore the strategies to facilitate operational performance enhancement.
文摘Public transport system has been a means of addressing transportation challenges in urban areas, such as traffic congestion, traffic jam and long travel time in cities worldwide. Transportation in Africa is unique in that it has the least developed public transport systems in the world, while also being one of the fastest urbanizing continents. Bus Rapid Transit being one of the public transport systems was introduced in Africa in 2008 as a means to provide solution on urban transportation challenges. Despite of public transport being the main means of transport in African developing countries, there have been a number of challenges that affects efficiency of performance of the system and makes its users uncomfortable. Therefore, the study aimed at exploring the setbacks or challenges associated with operation and performance of the BRT system in the African developing countries and address them. The study employed mixed methods research design that integrates both qualitative and quantitative data collection methods and analysis. The study findings reveal that, there is an improvement on the perspectives of the commuters on public transport after introduction of BRT system. However, some challenges such as long waiting time, passengers overcrowding during peak hours, as well as safety and security can slowly change the perspective of the commuters. Therefore, to address these challenges it is recommended to reduce the long waiting time and improve accessibility by introduction of passenger information displays (bus information system) and automated fare collection system;reduce travel time by introduction of bus priority signal;and improve safety and security by introduction of signage and CCTV Camera within the bus and bus stops.
基金This work was supported by the National Natural Science Foundation of China[grant number 41871308]the National Key R&D Program of China(International Scientific&Technological Cooperation Program)[grant number 2019YFE0106500]the Fundamental Research Funds for the Central Universities.
文摘Most of the current existing accessibility measures quantify the potential of reaching desirable opportunities across space and time.Nevertheless,these potential measurements only illus-trate the maximum possible accessibility a person can have,which may not accurately measure real-world transit accessibility in urban areas.This paper introduces a novel methodology to measure positive public transit accessibility based on multi-source big public transit data such as Smart Card Data(SCD)and Global Navigation Satellite System trajectory data,which embed rich travel information and real-world spatio-temporal constraints.First,we use multi-source transit data to reconstruct trip chains,which are used to extract popular destinations.A novel transit accessibility measure is defined to account for latent trip information such as mode/route preference,opportunity attraction,and travel impedance that are difficult to capture explicitly via traditional normative measures.Finally,we produce accessibility maps to visualize time-varying and heterogeneous accessibility patterns distributed over the study region.We performed an empirical evaluation on real-world transit data collected in Shenzhen City,China,demonstrating the applicability and effectiveness of the proposed method in mapping positive transit accessibility over large metropolitan areas.The results and findings of the empirical study demonstrate that the proposed positive accessibility measure can better capture travel behavior characteristics and constraints than traditional normative measures.The measure-ment method can be used as a practical high-resolution mapping tool for transit decision makers in evaluating public transit systems,supporting strategic transit planning,and improv-ing daily transit management.
文摘Reaching carbon neutrality will require investment on an unprecedented scale.Here we suggest that there is an underappreciated opportunity to leverage public funds to mobilize private capital in support of these aims.We illustrate the point using examples from public transit.Although the fuelling energy requirements of public fleets represent a small fraction of the eventual total demand across the transportation sector,the predictable and long-term nature of the refuelling profiles can reduce the financing risk.With appropriate coordination across the energy supply chain,near-term investments can be used to support scale-up of wider efforts to decarbonize the transportation sector and electric grid.We present two examples from California-one related to overnight power for battery electric bus charging and the other related to medium-scale supply chains for zero-carbon hydrogen production-to illustrate how this might be achieved.
基金Projects(71301115,71271150,71101102)supported by the National Natural Science Foundation of ChinaProject(20130032120009)supported by Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘The traditional manner to design public transportation system is to sequentially design the transit network and public bicycle network. A new public transportation system design problem that simultaneously considers both bus network design and public bicycle network design is proposed. The chemical reaction optimization(CRO) is designed to solve the problem. A shortcoming of CRO is that, when the two-molecule collisions take place, the molecules are randomly picked from the container.Hence, we improve CRO by employing different mating strategies. The computational results confirm the benefits of the mating strategies. Numerical experiments are conducted on the Sioux-Falls network. A comparison with the traditional sequential modeling framework indicates that the proposed approach has a better performance and is more robust. The practical applicability of the approach is proved by employing a real size network.
文摘The world is trying to recover from once in the COVID-19 pandemic, which has a higher mortality rate than the common flu. However, the threat of different variants is still affecting us in a different capacity. Several preventive measures have been adopted across the nation and the globe to avoid the spr<span style="font-family:Verdana;">ead of this virus, such as lockdown, restricted travel, social distancing guidelin</span><span style="font-family:Verdana;">es, obligatory face mask use, etc. These activities directly influenced the manag</span><span style="font-family:Verdana;">ement of social life, economy, and livelihoods. The effect of COVID-</span><span style="font-family:Verdana;">19 on the public transit industry and strategies the transit agencies adapted to continue providing the service during the pandemic has been synthesized in this pap</span><span style="font-family:Verdana;">er. As a result of the pandemic, public transit ridership decreased by abou</span><span style="font-family:Verdana;">t 70 percent for most agencies compared to pre-pandemic levels. This article also highlights the prevention of COVID-19 spread in the public transit industry using engineering solutions and advanced material science and nanotechnology solutions.</span>
