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
In order to provide important parameters for schedule designing, decision-making bases for transit operation management and references for passengers traveling by bus, bus transit travel time reliability is analyzed a...In order to provide important parameters for schedule designing, decision-making bases for transit operation management and references for passengers traveling by bus, bus transit travel time reliability is analyzed and evaluated based on automatic vehicle location (AVL) data. Based on the statistical analysis of the bus transit travel time, six indices including the coefficient of variance, the width of travel time distribution, the mean commercial speed, the congestion frequency, the planning time index and the buffer time index are proposed. Moreover, a framework for evaluating bus transit travel time reliability is constructed. Finally, a case study on a certain bus route in Suzhou is conducted. Results show that the proposed evaluation index system is simple and intuitive, and it can effectively reflect the efficiency and stability of bus operations. And a distinguishing feature of bus transit travel time reliability is the temporal pattern. It varies across different time periods.展开更多
This paper aims to develop a customer satisfaction model for bus rapid transit (BRT). Both the socio-economic and travel characteristics of passengers were considered to be independent variables. Changzhou BRT was t...This paper aims to develop a customer satisfaction model for bus rapid transit (BRT). Both the socio-economic and travel characteristics of passengers were considered to be independent variables. Changzhou BRT was taken as an example and on which on-board surveys were conducted to collect data. Ordinal logistic regression (OLR) was used as the modeling approach. The general OLR-based procedure for modeling customer satisfaction is proposed and based on which the customer satisfaction model of Changzhou BRT is developed. Some important findings are concluded: Waiting sub-journey affects customer satisfaction the most, riding sub- journey comes second and arriving station sub-journey has relatively fewer effects. The availability of shelter and benches at stations imposes heavy influence on customer satisfaction. Passengers' socio-economic characteristics have heavy impact on customer satisfaction.展开更多
In order to find the effect of different viscosity modifier dosages on asphalt binder's performance in bus rapid transit lanes in the city of Chengdu, three different viscosity modifiers were analyzed: TAFPACK-super...In order to find the effect of different viscosity modifier dosages on asphalt binder's performance in bus rapid transit lanes in the city of Chengdu, three different viscosity modifiers were analyzed: TAFPACK-super (TPS), high-viscosity additive (HVA) and road-science- technology (RST), and four different asphalt binders were investigated through laboratory experiments. The percent- ages of the viscosity modifiers used were: TPS (0%, 8%, 10%, 12%, 14% and 16%) and RST and HVA (8% and 12%) depending on the type of asphalt binder. Technical indicators of modifier asphalt were tested through con- ventional and unconventional binder tests. It has been found out that only a percentage greater than or equal to 14% TPS is reasonable to achieve the requirement set by 20,000 Pa. s for the 60℃ dynamic viscosity on local #70 grade asphalt. The results indicate that conventional bin- ders did not meet the requirements of the 60℃ dynamic viscosity when 12% of TPS or HVA modifiers were used. In addition, the B-type styrene-butadienne-styrene (SBS) modified asphalt binder has better viscosity balance than the A-type SBS modified when 8% of each of the three different kinds of viscosity modifiers is used. Therefore, the B-type modified SBS thus appears to be a suitable choice in asphalt mixtures for bus rapid transit lane with the 60℃ dynamic viscosity.展开更多
Service quality is a major factor that affects how public transport users evaluate bus service. In order to evaluate how bus users make trade-offs across travel cost,time,reliability,etc.,and to investigate the extent...Service quality is a major factor that affects how public transport users evaluate bus service. In order to evaluate how bus users make trade-offs across travel cost,time,reliability,etc.,and to investigate the extent to which the components of service quality vary according to relevant trip characteristics,this paper analyzes service quality of bus transit with the conjoint analysis. Through data analysis,the levels 'utility values of reliability,waiting time,walking time,etc.,on the commuter trip and the non-commuter trip are gotten,so it is the utility function of the transit system. Then the factors' weights are obtained through the utility values. The results show that on the commuter trip,passengers value reliability the most,which is followed by waiting time and walking time,while in-bus environment,price and station environment's weights are small. While on the non-commuter trip,the weights in a higher order to lower order are the first for reliability,the second for in-bus environment,the third for walking time,the fourth for station environment and the last for ticket price.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 (SE...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
The drive control system of the permanent magnetic direct current motor with the enhanced magnetism windings used in the electric transit bus is developed. The mathematics model of the drive control system for this mo...The drive control system of the permanent magnetic direct current motor with the enhanced magnetism windings used in the electric transit bus is developed. The mathematics model of the drive control system for this motor is established. The new mode that the added exiting magnetism field could be weakened and the speed of the motor could be controlled automatically is proposed and realized. The method of root locus design is applied to analyze the acceleration control characteristic. The results of simulation show that the new drive motor control system has extraordinary response characteristic and adjustable performance. Experiments of vehicle running show that the drive control system's antijamming ability is strong and the adjustable performance is fast and smooth, it can meet the demand of power characteristic very well.展开更多
The bustling urban environment of Kathmandu Valley is characterized by unprecedented traffic congestion. Due to its bowel-shaped geography, gusty winds rarely remove vehicular emissions from the urban atmosphere, maki...The bustling urban environment of Kathmandu Valley is characterized by unprecedented traffic congestion. Due to its bowel-shaped geography, gusty winds rarely remove vehicular emissions from the urban atmosphere, making Kathmandu one of Asia’s most polluted cities, 100th city in global pollution index. Over 500,000 vehicles travel daily on over 1600 km of roads covering over 675 sq·km urban area. Thousands of low occupancy vehicles are added each year to the urban public transit system (UPTS). Kathmandu faces worse and unreliable traffic from the current UPTS mostly with low occupancy vehicles. Around 4.5 million urban denizens, both permanent and transient residents, suffer from unreliable UPTS. Traffic rules and daily transportation schedules are rarely followed, resulting in frequent traffic jams and accidents. Once experienced, visitors try avoiding the UPTS. Tourism, annually contributing almost 8 percent to Nepal’s total annual GDP, also suffers from poor UPTS. Planners, policy makers, and politicians (P-actors) are seeking ways to improve sustainable UPTS to ameliorate stresses to family life and working hours for the urban majority. Aiming to help P-actors, we propose a transit-tracker model that uses real time information (RTI) in mobile phones and web-embedded devices to inform travelers, drivers, government authorities, and sub-admins. We argue that unreliability in the UPTS motivates urban elites to add more low occupancy vehicles, which in turn reduces already shrunken urban spaces and contributes more per capita air pollution than multi-occupancy vehicles. Since mobile and smart phones are capable of processing RTI to generate meaningful information and inform various stakeholders in communicable languages, we argue that replacing low occupancy vehicles with multi-occupancy buses within a Bus Rapid Transit (BRT) system, on main roads with fixed schedules and strict traffic rules, would not only improve UPTS, but also reduce pollution in the Kathmandu Valley.展开更多
Pedestrian safety related to public bus transit is an integral part of promoting sustainability especially in the urban setting. This concept has received significant attention within the last decade as transit agenci...Pedestrian safety related to public bus transit is an integral part of promoting sustainability especially in the urban setting. This concept has received significant attention within the last decade as transit agencies strive to make their systems more sustainable and safer at the same time. This study examined pedestrian collisions related to public transit buses in Philadelphia over a three-year study period from 2008 to 2011. The objective is to perform a detailed analysis on crash records, which provides the foundation on statistics for bus-pedestrian collision to allow for future studies in modeling work in this field. Results of this research provided insights on bus-pedestrian collisions in terms of bus maneuver, cause of crash, impact point of bus, and relation to hourly traffic volume. A strong correlation was found between traffic volume and bus-pedestrian collision rate in terms of hours of the day. For any given hour, an increase in collision frequency was found if the traffic volume exceeds a threshold of 5% of its average annual daily traffic. This serves as an indicator of locations that pedestrians are vulnerable at. Analyses were conducted to the fullest extent allowable by the limited dataset. This study presents findings that can be future developed and investigated in future studies. Additionally, countermeasures are recommended in each section that presents a critical area to address.展开更多
Bus rapid transit (BRT) systems have been implemented in many cities over the past two decades. Widespread adoption of General Transit Feed Specification (GTFS), the deployment of high-fidelity bus GPS data tracking, ...Bus rapid transit (BRT) systems have been implemented in many cities over the past two decades. Widespread adoption of General Transit Feed Specification (GTFS), the deployment of high-fidelity bus GPS data tracking, and anonymized high-fidelity connected vehicle data from private vehicles have provided new opportunities for performance measures that can be used by both transit agencies and traffic signal system operators. This paper describes the use of trajectory-based data to develop performance measures for a BRT system in Indianapolis, Indiana. Over 3 million data records during the 3-month period between March and May 2022 are analyzed to develop visualizations and performance metrics. A methodology to estimate the average delay and schedule adherence is presented along a route comprised of 74 signals and 28 bus stations. Additionally, this research demonstrates how these performance measures can be used to evaluate dedicated and non-dedicated bus lanes with general traffic. Travel times and reliability of buses are compared with nearly 30 million private vehicle trips. Results show that median travel time for buses on dedicated bi-directional lanes is within one minute of general traffic and during peak periods the buses are often faster. Schedule adherence was observed to be more challenging, with approximately 3% of buses arriving within 1 minute on average during the 5AM hour and 5% of buses arriving 6 - 9 minutes late during the 5PM hour. The framework and performance measures presented in this research provide agencies and transportation professionals with tools to identify opportunities for adjustments and to justify investment decisions.展开更多
Bus rapid transit (BRT) systems have been shown to have many advantages including affordability, high capacity vehicles, and reliable service. Due to these attractive advantages, many cities throughout the world are...Bus rapid transit (BRT) systems have been shown to have many advantages including affordability, high capacity vehicles, and reliable service. Due to these attractive advantages, many cities throughout the world are in the process of planning the construction of BRT systems. To improve the performance of BRT systems, many researchers study BRT operation and control, which include the study of dwell times at bus/BRT stations. To ensure the effectiveness of real-time control which aims to avoid bus/BRT vehicles congestion, accurate dwell time models are needed. We develop our models using data from a BRT vehicle survey conducted in Changzhou, China, where BRT lines are built along passenger corridors, and BRT stations are enclosed like light rails. This means that interactions between passengers traveling on the BRT system are more frequent than those in traditional transit system who use platform stations. We statistically analyze the BRT vehicle survey data, and based on this analysis, we are able to make the following conclusions: ( I ) The delay time per passenger at a BRT station is less than that at a non-BRT station, which implies that BRT stations are efficient in the sense that they are able to move passengers quickly. (II) The dwell time follows a logarithmic normal distribution with a mean of 2.56 and a variance of 0.53. (III) The greater the number of BRT lines serviced by a station, the longer the dwell time is. (IV) Daily travel demands are highest during the morning peak interval where the dwell time, the number of passengers boarding and alighting and the number of passengers on vehicles reach their maximum values. (V) The dwell time is highly positively correlated with the total number of passengers boarding and alighting. (VI) The delay per passenger is negatively correlated with the total number of passengers boarding and alighting. We propose two dwell time models for the BRT station. The first proposed model is a linear model while the second is nonlinear. We introduce the conflict between passengers boarding and alighting into our models. Finally, by comparing our models with the models of Rajbhandari and Chien et al., and TCQSM (Transit Capacity and Quality of Service Manual), we conclude that the proposed nonlinear model can better predict the dwell time at BRT stations.展开更多
Bus Rapid Transit(BRT)has emerged as a preferred mode of public transport in various countries all over the world for its cost effectiveness in construction as well as in operation and maintenance.The rapid transit fe...Bus Rapid Transit(BRT)has emerged as a preferred mode of public transport in various countries all over the world for its cost effectiveness in construction as well as in operation and maintenance.The rapid transit feature of BRT is seen as a solution to many traffic problems in these countries.However,in developing countries like India,the right–of-way for most of the roads is restricted and traffic is heterogeneous in nature.Provision of BRT in existing right–ofway reduces the capacity available for other motorized traffic.As the buses travel with a certain frequency on dedicated bus-ways,the dedicated corridor remains unused for most of the period when other traffic on motorized vehicle(MV)lanes suffers from congestion.The problem gets severe at intersections.However,if buses are operated in mixed traffic it is no more rapid transit.Hence,a solution is required to address this problem and optimize the performance of traffic as a whole.This paper presents the effect if dedicated bus-ways end at a reasonable distance before the stop line at a busy signalized at-grade intersection,and bus lanes(beyond that)are made available to all the motorized vehicular traffic(heterogeneous traffic)at intersection.The performance evaluation is done in terms of average queue length,maximum queue length,average delay time per vehicle,vehicle throughput,average speed in network and emission of Carbon monoxide CO,mono-nitrogen oxides NOx and Volatile organic compounds(VOC).It is observed that availability of bus lanes to other motorized traffic for a reasonable distance before intersection considerably reduces the average queue length,maximum queue length,average delay time per vehicle and emission per vehicle,while there is an increase in vehicle throughput and average speed of all the vehicles in the network.Thus it results in reduction of congestion and performance enhancement of at-grade intersections and network.Results of investigation are relevant in international context.VISSIM,a microscopic simulation tool,is used to model the heterogeneous traffic and public transit lines under constraints of roadway geometry,vehicle characteristics,driving behaviour and traffic controls.The effect is investigated with different random seeds to obtain reasonable results for analysis.展开更多
To accurately capture the measurement of bus reliability and evaluate whether the transit system is properly operated an evaluation framework is established to assess the reliability of the transit system from differe...To accurately capture the measurement of bus reliability and evaluate whether the transit system is properly operated an evaluation framework is established to assess the reliability of the transit system from different stratifications including stops routes and network levels.The bus operation data of the Hefei city is analyzed as a case study.Comparison is conducted to show the improvement made by using the advanced method and an example of adding exclusive bus lanes to the existing bus route is provided. The proposed advanced method can avoid the shortcomings of the traditional method.For example the value of the reliability using the traditional coefficient of variation CV is not between 0 and 1 and the value of reliability can decrease with the increase in the transit headway etc. The case study shows that the advanced method can represent the real operation condition of the transit system and can be used to evaluate the transit headway reliability more reasonably.展开更多
Various transportation systems have been developed in recent years.In this study,an artificial society model is developed to examine the combination of transportation policies in urban areas.In this model,each trip ma...Various transportation systems have been developed in recent years.In this study,an artificial society model is developed to examine the combination of transportation policies in urban areas.In this model,each trip maker selects the primary and terminal transportation modes.An artificial society model is applied to the southeastern region of Osaka City,Japan.The effects of introducing BRT(bus rapid transit,primary transportation)and on-demand buses(terminal transportation)are investigated.The results confirm that BRT is used by a certain number of users.An increase in the use of BRT will increase the amount of walking,thus resulting in a healthy city.However,on-demand buses are rarely used as terminal transportation.Additionally,the development of bicycle parking stations near BRT stops is shown to be effective in the northern section of the BRT route.展开更多
As a major mode choice of commuters for daily travel, bus transit plays an important role in many urban and metropolitan areas. This work proposes a mathematical model to optimize bus service by minimizing total cost ...As a major mode choice of commuters for daily travel, bus transit plays an important role in many urban and metropolitan areas. This work proposes a mathematical model to optimize bus service by minimizing total cost and considering a temporally and directionally variable demand. An integrated bus service, consisting of all-stop and stop-skipping services is proposed and optimized subject to directional frequency conservation, capacity and operable fleet size constraints. Since the research problem is a combinatorial optimization problem, a genetic algorithm is developed to search for the optimal result in a large solution space. The model was successfully implemented on a bus transit route in the City of Chengdu, China, and the optimal solution was proved to be better than the original operation in terms of total cost. The sensitivity of model parameters to some key attributes/variables is analyzed and discussed to explore further the potential of accruing additional benefits or avoiding some of the drawbacks of stop-skipping services.展开更多
Traditionally, the process used by public transportation entities to determine the acquisition strategy for new vehicle asset is based upon a broad range of criteria. Vehicle cost has been cited as one of the more cri...Traditionally, the process used by public transportation entities to determine the acquisition strategy for new vehicle asset is based upon a broad range of criteria. Vehicle cost has been cited as one of the more critical factors which decision makers consider. It is currently a common practice to consider other factors (life-cycle cost, fuel efficiency, vehicle reliability, environmental effects, etc.) that contribute to a more comprehensive approach. This study investigates the next generation of advancements in decision making tools in the area of the application of methods to quantify and manage uncertainty. In particular, the uncertainty comes from the public policy arena where future policy and regulations are not always based upon logical and predictable processes. The fleet decision making process in most governmental agencies is a very complex and interdependent activity. There are always competing forces and agendas within the view of the decision maker. Rarely is the decision maker a single person although, within the transit environment, there is often one person charged with the responsibility of fleet management. The focus of this research examines the decision making of the general transit agency community via the development of an expert systems prototype tool. A computer-based prototype system is developed which provide an expert knowledge-based recommendation, based upon variable user inputs. The results shown in this study show that a decision making tool for the management of transit system alternate fuel vehicle assets can be modeled and tested. The direct users of this research are the transit agency administrations. The results can be used by the management teams as a reliable input to inform their urban transit buses expansion decision making process.展开更多
This paper evaluates rail transit within the context of the transit policies implemented in Lima,Peru.First it reviews the implementation of rapid transit,and bus reform.Secondly,it evaluates the outcomes of such poli...This paper evaluates rail transit within the context of the transit policies implemented in Lima,Peru.First it reviews the implementation of rapid transit,and bus reform.Secondly,it evaluates the outcomes of such policies by using Total Factor Productivity for policy effectiveness,Data Envelopment Analysis for rapid transit performance,and Generalized Cost of Travel for improvements.This paper finds that implementation failed in enforcing key requirements for rail transit regarding penetration of CBD and short transfers to bus transit;and that the basic assumptions of bus reform did not hold regarding bus oversupply,bus congestion or bus pollution.This paper also finds that outcomes of policies failed dramatically in achieving the planning goals;however,rail transit(Metro)shows high level of resilience in serving large ridership at high speed.On the other hand,bus reform was associated with a disproportionate increase of motorization,well over the effect of income growth or car attractiveness,and more related to the excessive reduction of bus transit capacity ill-advised from unproved bus reform assumptions.This paper recommends expanding rail rapid transit due to its intensive use of green renewable energy and its potential of demand growth if combined with modern Intelligent Transportation services,but this opportunity can be wasted without the proposed policy constraint to achieve lower Generalized Cost of Travel at any governmental intervention for bus reform,instead of just reducing bus transit capacity as implemented.Finally,this paper recommends government to government contracts to build rail transit and to enforce proper planning.展开更多
Urban rail transit (URT) disruptions present considerable challenges due to several factors: i) a high probability of occurrence, arising from facility failures, disasters, and vandalism;ii) substantial negative effec...Urban rail transit (URT) disruptions present considerable challenges due to several factors: i) a high probability of occurrence, arising from facility failures, disasters, and vandalism;ii) substantial negative effects, notably the delay of numerous passengers;iii) an escalating frequency, attributable to the gradual aging of facilities;and iv) severe penalties, including substantial fines for abnormal operation. This article systematically reviews URT disruption management literature from the past decade, categorizing it into pre-disruption and post-disruption measures. The pre-disruption research focuses on reducing the effects of disruptions through network analysis, passenger behavior analysis, resource allocation for protection and backup, and enhancing system resilience. Conversely, post-disruption research concentrates on restoring normal operations through train rescheduling and bus bridging services. The review reveals that while post-disruption strategies are thoroughly explored, pre-disruption research is predominantly analytical, with a scarcity of practical pre-emptive solutions. Moreover, future research should focus more on increasing the interchangeability of transport modes, reinforcing redundancy relationships between URT lines, and innovating post-disruption strategies.展开更多
Given that energy conservation and environmental protection are two important goals for the automotive industry, the application of a hybrid electric powertrain can improve vehicle energy efficiency while decreasing f...Given that energy conservation and environmental protection are two important goals for the automotive industry, the application of a hybrid electric powertrain can improve vehicle energy efficiency while decreasing fuel consumption and engine emissions. Planetary gear-based power-split hybrid powertrains have become widely used in passenger vehicles, but remain rarely employed on transit buses. This study proposes a novel hybrid powertrain based on two planetary gear sets(CHS) and presents its operating principles along with development of a control strategy for the powertrain. The CHS hybrid powertrain operates in electric mode when the driving power demand is low, and changes to a hybrid electric mode according to the power-split principle of the planetary gear set. To validate the feasibility of the designed CHS hybrid powertrain, a prototype transit bus equipped with the designed hybrid powertrain system was built, and the operating characteristics of the system were analyzed through a performance test conducted on a chassis dynamometer. Compared with a conventional powertrain, the CHS hybrid powertrain can reduce fuel consumption by 39%. Thus, the CHS hybrid powertrain is a good solution for heavy-duty applications such as hybrid transit buses because of its simple structure and excellent fuel efficiency.展开更多
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The Soft Science Research Project of Ministry of Housing and Urban-Rural Development of China (No. 2008-k5-14)
文摘In order to provide important parameters for schedule designing, decision-making bases for transit operation management and references for passengers traveling by bus, bus transit travel time reliability is analyzed and evaluated based on automatic vehicle location (AVL) data. Based on the statistical analysis of the bus transit travel time, six indices including the coefficient of variance, the width of travel time distribution, the mean commercial speed, the congestion frequency, the planning time index and the buffer time index are proposed. Moreover, a framework for evaluating bus transit travel time reliability is constructed. Finally, a case study on a certain bus route in Suzhou is conducted. Results show that the proposed evaluation index system is simple and intuitive, and it can effectively reflect the efficiency and stability of bus operations. And a distinguishing feature of bus transit travel time reliability is the temporal pattern. It varies across different time periods.
基金The National Natural Science Foundation of China(No.61573098)the Scientific Research Projects in Universities of Inner Mongolia(No.NJZY16022)
文摘This paper aims to develop a customer satisfaction model for bus rapid transit (BRT). Both the socio-economic and travel characteristics of passengers were considered to be independent variables. Changzhou BRT was taken as an example and on which on-board surveys were conducted to collect data. Ordinal logistic regression (OLR) was used as the modeling approach. The general OLR-based procedure for modeling customer satisfaction is proposed and based on which the customer satisfaction model of Changzhou BRT is developed. Some important findings are concluded: Waiting sub-journey affects customer satisfaction the most, riding sub- journey comes second and arriving station sub-journey has relatively fewer effects. The availability of shelter and benches at stations imposes heavy influence on customer satisfaction. Passengers' socio-economic characteristics have heavy impact on customer satisfaction.
文摘In order to find the effect of different viscosity modifier dosages on asphalt binder's performance in bus rapid transit lanes in the city of Chengdu, three different viscosity modifiers were analyzed: TAFPACK-super (TPS), high-viscosity additive (HVA) and road-science- technology (RST), and four different asphalt binders were investigated through laboratory experiments. The percent- ages of the viscosity modifiers used were: TPS (0%, 8%, 10%, 12%, 14% and 16%) and RST and HVA (8% and 12%) depending on the type of asphalt binder. Technical indicators of modifier asphalt were tested through con- ventional and unconventional binder tests. It has been found out that only a percentage greater than or equal to 14% TPS is reasonable to achieve the requirement set by 20,000 Pa. s for the 60℃ dynamic viscosity on local #70 grade asphalt. The results indicate that conventional bin- ders did not meet the requirements of the 60℃ dynamic viscosity when 12% of TPS or HVA modifiers were used. In addition, the B-type styrene-butadienne-styrene (SBS) modified asphalt binder has better viscosity balance than the A-type SBS modified when 8% of each of the three different kinds of viscosity modifiers is used. Therefore, the B-type modified SBS thus appears to be a suitable choice in asphalt mixtures for bus rapid transit lane with the 60℃ dynamic viscosity.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51208261)the Science Foundation of Ministry of Education of China(Grant No.12YJCZH062)
文摘Service quality is a major factor that affects how public transport users evaluate bus service. In order to evaluate how bus users make trade-offs across travel cost,time,reliability,etc.,and to investigate the extent to which the components of service quality vary according to relevant trip characteristics,this paper analyzes service quality of bus transit with the conjoint analysis. Through data analysis,the levels 'utility values of reliability,waiting time,walking time,etc.,on the commuter trip and the non-commuter trip are gotten,so it is the utility function of the transit system. Then the factors' weights are obtained through the utility values. The results show that on the commuter trip,passengers value reliability the most,which is followed by waiting time and walking time,while in-bus environment,price and station environment's weights are small. While on the non-commuter trip,the weights in a higher order to lower order are the first for reliability,the second for in-bus environment,the third for walking time,the fourth for station environment and the last for ticket price.
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The drive control system of the permanent magnetic direct current motor with the enhanced magnetism windings used in the electric transit bus is developed. The mathematics model of the drive control system for this motor is established. The new mode that the added exiting magnetism field could be weakened and the speed of the motor could be controlled automatically is proposed and realized. The method of root locus design is applied to analyze the acceleration control characteristic. The results of simulation show that the new drive motor control system has extraordinary response characteristic and adjustable performance. Experiments of vehicle running show that the drive control system's antijamming ability is strong and the adjustable performance is fast and smooth, it can meet the demand of power characteristic very well.
文摘The bustling urban environment of Kathmandu Valley is characterized by unprecedented traffic congestion. Due to its bowel-shaped geography, gusty winds rarely remove vehicular emissions from the urban atmosphere, making Kathmandu one of Asia’s most polluted cities, 100th city in global pollution index. Over 500,000 vehicles travel daily on over 1600 km of roads covering over 675 sq·km urban area. Thousands of low occupancy vehicles are added each year to the urban public transit system (UPTS). Kathmandu faces worse and unreliable traffic from the current UPTS mostly with low occupancy vehicles. Around 4.5 million urban denizens, both permanent and transient residents, suffer from unreliable UPTS. Traffic rules and daily transportation schedules are rarely followed, resulting in frequent traffic jams and accidents. Once experienced, visitors try avoiding the UPTS. Tourism, annually contributing almost 8 percent to Nepal’s total annual GDP, also suffers from poor UPTS. Planners, policy makers, and politicians (P-actors) are seeking ways to improve sustainable UPTS to ameliorate stresses to family life and working hours for the urban majority. Aiming to help P-actors, we propose a transit-tracker model that uses real time information (RTI) in mobile phones and web-embedded devices to inform travelers, drivers, government authorities, and sub-admins. We argue that unreliability in the UPTS motivates urban elites to add more low occupancy vehicles, which in turn reduces already shrunken urban spaces and contributes more per capita air pollution than multi-occupancy vehicles. Since mobile and smart phones are capable of processing RTI to generate meaningful information and inform various stakeholders in communicable languages, we argue that replacing low occupancy vehicles with multi-occupancy buses within a Bus Rapid Transit (BRT) system, on main roads with fixed schedules and strict traffic rules, would not only improve UPTS, but also reduce pollution in the Kathmandu Valley.
文摘Pedestrian safety related to public bus transit is an integral part of promoting sustainability especially in the urban setting. This concept has received significant attention within the last decade as transit agencies strive to make their systems more sustainable and safer at the same time. This study examined pedestrian collisions related to public transit buses in Philadelphia over a three-year study period from 2008 to 2011. The objective is to perform a detailed analysis on crash records, which provides the foundation on statistics for bus-pedestrian collision to allow for future studies in modeling work in this field. Results of this research provided insights on bus-pedestrian collisions in terms of bus maneuver, cause of crash, impact point of bus, and relation to hourly traffic volume. A strong correlation was found between traffic volume and bus-pedestrian collision rate in terms of hours of the day. For any given hour, an increase in collision frequency was found if the traffic volume exceeds a threshold of 5% of its average annual daily traffic. This serves as an indicator of locations that pedestrians are vulnerable at. Analyses were conducted to the fullest extent allowable by the limited dataset. This study presents findings that can be future developed and investigated in future studies. Additionally, countermeasures are recommended in each section that presents a critical area to address.
文摘Bus rapid transit (BRT) systems have been implemented in many cities over the past two decades. Widespread adoption of General Transit Feed Specification (GTFS), the deployment of high-fidelity bus GPS data tracking, and anonymized high-fidelity connected vehicle data from private vehicles have provided new opportunities for performance measures that can be used by both transit agencies and traffic signal system operators. This paper describes the use of trajectory-based data to develop performance measures for a BRT system in Indianapolis, Indiana. Over 3 million data records during the 3-month period between March and May 2022 are analyzed to develop visualizations and performance metrics. A methodology to estimate the average delay and schedule adherence is presented along a route comprised of 74 signals and 28 bus stations. Additionally, this research demonstrates how these performance measures can be used to evaluate dedicated and non-dedicated bus lanes with general traffic. Travel times and reliability of buses are compared with nearly 30 million private vehicle trips. Results show that median travel time for buses on dedicated bi-directional lanes is within one minute of general traffic and during peak periods the buses are often faster. Schedule adherence was observed to be more challenging, with approximately 3% of buses arriving within 1 minute on average during the 5AM hour and 5% of buses arriving 6 - 9 minutes late during the 5PM hour. The framework and performance measures presented in this research provide agencies and transportation professionals with tools to identify opportunities for adjustments and to justify investment decisions.
基金supported by the National Scienceand Technology Support Program of China (No.2009BAG17B01)
文摘Bus rapid transit (BRT) systems have been shown to have many advantages including affordability, high capacity vehicles, and reliable service. Due to these attractive advantages, many cities throughout the world are in the process of planning the construction of BRT systems. To improve the performance of BRT systems, many researchers study BRT operation and control, which include the study of dwell times at bus/BRT stations. To ensure the effectiveness of real-time control which aims to avoid bus/BRT vehicles congestion, accurate dwell time models are needed. We develop our models using data from a BRT vehicle survey conducted in Changzhou, China, where BRT lines are built along passenger corridors, and BRT stations are enclosed like light rails. This means that interactions between passengers traveling on the BRT system are more frequent than those in traditional transit system who use platform stations. We statistically analyze the BRT vehicle survey data, and based on this analysis, we are able to make the following conclusions: ( I ) The delay time per passenger at a BRT station is less than that at a non-BRT station, which implies that BRT stations are efficient in the sense that they are able to move passengers quickly. (II) The dwell time follows a logarithmic normal distribution with a mean of 2.56 and a variance of 0.53. (III) The greater the number of BRT lines serviced by a station, the longer the dwell time is. (IV) Daily travel demands are highest during the morning peak interval where the dwell time, the number of passengers boarding and alighting and the number of passengers on vehicles reach their maximum values. (V) The dwell time is highly positively correlated with the total number of passengers boarding and alighting. (VI) The delay per passenger is negatively correlated with the total number of passengers boarding and alighting. We propose two dwell time models for the BRT station. The first proposed model is a linear model while the second is nonlinear. We introduce the conflict between passengers boarding and alighting into our models. Finally, by comparing our models with the models of Rajbhandari and Chien et al., and TCQSM (Transit Capacity and Quality of Service Manual), we conclude that the proposed nonlinear model can better predict the dwell time at BRT stations.
文摘Bus Rapid Transit(BRT)has emerged as a preferred mode of public transport in various countries all over the world for its cost effectiveness in construction as well as in operation and maintenance.The rapid transit feature of BRT is seen as a solution to many traffic problems in these countries.However,in developing countries like India,the right–of-way for most of the roads is restricted and traffic is heterogeneous in nature.Provision of BRT in existing right–ofway reduces the capacity available for other motorized traffic.As the buses travel with a certain frequency on dedicated bus-ways,the dedicated corridor remains unused for most of the period when other traffic on motorized vehicle(MV)lanes suffers from congestion.The problem gets severe at intersections.However,if buses are operated in mixed traffic it is no more rapid transit.Hence,a solution is required to address this problem and optimize the performance of traffic as a whole.This paper presents the effect if dedicated bus-ways end at a reasonable distance before the stop line at a busy signalized at-grade intersection,and bus lanes(beyond that)are made available to all the motorized vehicular traffic(heterogeneous traffic)at intersection.The performance evaluation is done in terms of average queue length,maximum queue length,average delay time per vehicle,vehicle throughput,average speed in network and emission of Carbon monoxide CO,mono-nitrogen oxides NOx and Volatile organic compounds(VOC).It is observed that availability of bus lanes to other motorized traffic for a reasonable distance before intersection considerably reduces the average queue length,maximum queue length,average delay time per vehicle and emission per vehicle,while there is an increase in vehicle throughput and average speed of all the vehicles in the network.Thus it results in reduction of congestion and performance enhancement of at-grade intersections and network.Results of investigation are relevant in international context.VISSIM,a microscopic simulation tool,is used to model the heterogeneous traffic and public transit lines under constraints of roadway geometry,vehicle characteristics,driving behaviour and traffic controls.The effect is investigated with different random seeds to obtain reasonable results for analysis.
基金The National Basic Research Program of China(973 Program)(No.2012CB725402)the National Natural Science Foundation of China(No.51208099,50978057)
文摘To accurately capture the measurement of bus reliability and evaluate whether the transit system is properly operated an evaluation framework is established to assess the reliability of the transit system from different stratifications including stops routes and network levels.The bus operation data of the Hefei city is analyzed as a case study.Comparison is conducted to show the improvement made by using the advanced method and an example of adding exclusive bus lanes to the existing bus route is provided. The proposed advanced method can avoid the shortcomings of the traditional method.For example the value of the reliability using the traditional coefficient of variation CV is not between 0 and 1 and the value of reliability can decrease with the increase in the transit headway etc. The case study shows that the advanced method can represent the real operation condition of the transit system and can be used to evaluate the transit headway reliability more reasonably.
基金supported by JSPS KAKENHI(grant number:21K04307).
文摘Various transportation systems have been developed in recent years.In this study,an artificial society model is developed to examine the combination of transportation policies in urban areas.In this model,each trip maker selects the primary and terminal transportation modes.An artificial society model is applied to the southeastern region of Osaka City,Japan.The effects of introducing BRT(bus rapid transit,primary transportation)and on-demand buses(terminal transportation)are investigated.The results confirm that BRT is used by a certain number of users.An increase in the use of BRT will increase the amount of walking,thus resulting in a healthy city.However,on-demand buses are rarely used as terminal transportation.Additionally,the development of bicycle parking stations near BRT stops is shown to be effective in the northern section of the BRT route.
基金Project(B01B1203)supported by Sichuan Province Key Laboratory of Comprehensive Transportation,ChinaProject(SWJTU09BR141)supported by the Southwest Jiaotong University,China
文摘As a major mode choice of commuters for daily travel, bus transit plays an important role in many urban and metropolitan areas. This work proposes a mathematical model to optimize bus service by minimizing total cost and considering a temporally and directionally variable demand. An integrated bus service, consisting of all-stop and stop-skipping services is proposed and optimized subject to directional frequency conservation, capacity and operable fleet size constraints. Since the research problem is a combinatorial optimization problem, a genetic algorithm is developed to search for the optimal result in a large solution space. The model was successfully implemented on a bus transit route in the City of Chengdu, China, and the optimal solution was proved to be better than the original operation in terms of total cost. The sensitivity of model parameters to some key attributes/variables is analyzed and discussed to explore further the potential of accruing additional benefits or avoiding some of the drawbacks of stop-skipping services.
文摘Traditionally, the process used by public transportation entities to determine the acquisition strategy for new vehicle asset is based upon a broad range of criteria. Vehicle cost has been cited as one of the more critical factors which decision makers consider. It is currently a common practice to consider other factors (life-cycle cost, fuel efficiency, vehicle reliability, environmental effects, etc.) that contribute to a more comprehensive approach. This study investigates the next generation of advancements in decision making tools in the area of the application of methods to quantify and manage uncertainty. In particular, the uncertainty comes from the public policy arena where future policy and regulations are not always based upon logical and predictable processes. The fleet decision making process in most governmental agencies is a very complex and interdependent activity. There are always competing forces and agendas within the view of the decision maker. Rarely is the decision maker a single person although, within the transit environment, there is often one person charged with the responsibility of fleet management. The focus of this research examines the decision making of the general transit agency community via the development of an expert systems prototype tool. A computer-based prototype system is developed which provide an expert knowledge-based recommendation, based upon variable user inputs. The results shown in this study show that a decision making tool for the management of transit system alternate fuel vehicle assets can be modeled and tested. The direct users of this research are the transit agency administrations. The results can be used by the management teams as a reliable input to inform their urban transit buses expansion decision making process.
文摘This paper evaluates rail transit within the context of the transit policies implemented in Lima,Peru.First it reviews the implementation of rapid transit,and bus reform.Secondly,it evaluates the outcomes of such policies by using Total Factor Productivity for policy effectiveness,Data Envelopment Analysis for rapid transit performance,and Generalized Cost of Travel for improvements.This paper finds that implementation failed in enforcing key requirements for rail transit regarding penetration of CBD and short transfers to bus transit;and that the basic assumptions of bus reform did not hold regarding bus oversupply,bus congestion or bus pollution.This paper also finds that outcomes of policies failed dramatically in achieving the planning goals;however,rail transit(Metro)shows high level of resilience in serving large ridership at high speed.On the other hand,bus reform was associated with a disproportionate increase of motorization,well over the effect of income growth or car attractiveness,and more related to the excessive reduction of bus transit capacity ill-advised from unproved bus reform assumptions.This paper recommends expanding rail rapid transit due to its intensive use of green renewable energy and its potential of demand growth if combined with modern Intelligent Transportation services,but this opportunity can be wasted without the proposed policy constraint to achieve lower Generalized Cost of Travel at any governmental intervention for bus reform,instead of just reducing bus transit capacity as implemented.Finally,this paper recommends government to government contracts to build rail transit and to enforce proper planning.
基金supported by the National Natural Science Foundation of China(Grant Nos.72122014 and 72061127003)the Sustainable Urban Future Laboratory of ZJU-UIUC Institute.
文摘Urban rail transit (URT) disruptions present considerable challenges due to several factors: i) a high probability of occurrence, arising from facility failures, disasters, and vandalism;ii) substantial negative effects, notably the delay of numerous passengers;iii) an escalating frequency, attributable to the gradual aging of facilities;and iv) severe penalties, including substantial fines for abnormal operation. This article systematically reviews URT disruption management literature from the past decade, categorizing it into pre-disruption and post-disruption measures. The pre-disruption research focuses on reducing the effects of disruptions through network analysis, passenger behavior analysis, resource allocation for protection and backup, and enhancing system resilience. Conversely, post-disruption research concentrates on restoring normal operations through train rescheduling and bus bridging services. The review reveals that while post-disruption strategies are thoroughly explored, pre-disruption research is predominantly analytical, with a scarcity of practical pre-emptive solutions. Moreover, future research should focus more on increasing the interchangeability of transport modes, reinforcing redundancy relationships between URT lines, and innovating post-disruption strategies.
文摘Given that energy conservation and environmental protection are two important goals for the automotive industry, the application of a hybrid electric powertrain can improve vehicle energy efficiency while decreasing fuel consumption and engine emissions. Planetary gear-based power-split hybrid powertrains have become widely used in passenger vehicles, but remain rarely employed on transit buses. This study proposes a novel hybrid powertrain based on two planetary gear sets(CHS) and presents its operating principles along with development of a control strategy for the powertrain. The CHS hybrid powertrain operates in electric mode when the driving power demand is low, and changes to a hybrid electric mode according to the power-split principle of the planetary gear set. To validate the feasibility of the designed CHS hybrid powertrain, a prototype transit bus equipped with the designed hybrid powertrain system was built, and the operating characteristics of the system were analyzed through a performance test conducted on a chassis dynamometer. Compared with a conventional powertrain, the CHS hybrid powertrain can reduce fuel consumption by 39%. Thus, the CHS hybrid powertrain is a good solution for heavy-duty applications such as hybrid transit buses because of its simple structure and excellent fuel efficiency.