Metro Transit System Research Articles

Small things, big impact: The network-mediated spillover effect through a transport connectivity enhancement project

This study examines a 4.3 km expansion of Singapore's metro transit system. Despite a short line, it better connected existing lines and improved the connectivity levels of numerous stations across the city, as evidenced by connectivity indices. The improvement allowed residents living near those stations to access other places more easily, leading to greater convenience and higher home value in those stations' neighborhoods. Using difference-in-differences to compare housing price and connectivity changes in all neighborhoods with or without a station, we find that a 1% improvement in connectivity can increase local housing prices by 0.37%. The identification is anchored to the broad impact of the network reconfiguration, which was caused by the new transport infrastructure, on the connectivity changes in distant areas. Several techniques and tests enhance robustness. These include an estimation of the treatment boundary that defines proximity to stations, propensity score matching or weighting to mitigate sample imbalance, event study for the parallel trend, parameter sensitivity tests, etc. The research highlights that a small transport project can generate broad impacts on the whole city.

Post-COVID-19 performance evaluation of urban metro transit system in Delhi and influence on access mode

The impact of the COVID-19 pandemic has been observed to affect the travel patterns, routes and traffic in public transportation systems across the world. It is important to evaluate the performance of the Delhi Metro (DM) post-COVID-19 pandemic for its successful operation. In this study, the BLUE line of DM with the longest route and highest number of metro stations has been examined for performance evaluation. The performance is evaluated based on travel time components (access, egress, transfer, waiting and main haul time) to calculate various performance indicators i.e., Level of Service (LOS), Service Time Ratio (STR), Passengers Waiting Index (PWI), Total Travel Ratio (TTR) and Interconnectivity Ratio (IR). The post-COVID-19 LOS evaluation indicates that the users are spending 72.6 % to 84.4 % of their main haul time on their access-egress trips. The STR shows that the users are spending 10.9 % to 12.6 % of their total travel time in waiting and transferring only during the main haul trip. The mean PWI, RI and TTR are noted as 1.008, 0.794 and 2.069 respectively. The IR is observed as 0.312 for the given route. The median and average main haul distances across all access modes are observed to be (12–21) Km. and (19.69 ± 11.19) Km. respectively. It is revealed that the observed mean value of LOS is (0.775 ± 0.575). It is further revealed that the metro fare per trip and the access-egress trip cost per day are significant factors for access mode choice in the case of walking and auto-rickshaw whereas LOS, RI and PWI are other significant operator’s performance indicators influencing the access mode choice. The study reveals that post-COVID-19 the performance indicators exhibit the unsatisfactory performance of DM and there is further scope to improve the UMTS performance.

Causal association between metro transits and air quality: China's evidence.

In policy remedies, transportation infrastructure such as metro transit is widely considered to be an important and effective means to reduce air pollution. However, the policy prediction that metro transits reduce air pollution depends on driver responses. China provides an appropriate context to explore the answer since its major cities have expanded their metro transit systems in recent years, which enables us to exploit a natural experiment. Accordingly, a sharp regression discontinuity is employed to evaluate the impact of 112 metro lines (with an accumulation of 3286km) on air quality. Evidence shows that the opening of metro transits has a negative causal effect on air pollution. The results are robust to several alternative specifications. Furthermore, a heterogeneity analysis demonstrates that metro openings have a time-varying impact on air pollution, which is larger during rush hours. We anticipate that the air quality improvement in China caused by metro transits can generate large welfare gains.

Mixed network DEA models with shared resources for measuring and decomposing performance of public transportation systems

This study proposes a hybrid two-stage network model and a mixed network DEA with the shared-inputs model to jointly measure the efficiency and effectiveness of a metro transport system. Performance is determined by the hybrid two-stage network DEA with the shared-inputs model to account for the non-storable service feature. In contrast, the mixed network DEA model with the shared-inputs is used to describe the metro system's non-storable service, joint-product, and multi-subsystems features. Shared resources are analyzed by these two models to determine which common input resources are shared among multiple processes. A case study is conducted with the two models to evaluate and decompose the performance of a metro transit system. Results from the hybrid two-stage network and mixed network DEA models indicate that the performance measures or ranks differ significantly when using non-parametrical statistical tests. Transit system operators can gain more complete performance information on subsystems from the results of the mixed network DEA model than from the hybrid two-stage network model, enabling further improvements to their systems and sub-systems.

Full Battery and Hybrid Bus based Rapid Transit System as a Cost Effective Urban Transit Mode alternative to Metros in Tier II Tier II I Indian Cities

Intra-city travel is a significant part of urban life and a fully functional intra-city transit system will help in reducing the number of private vehicles on the road, thus reducing pollution and traffic congestions. A robust urban transit system helps in the physical expansion of city limits, making education, job, and medical facilities accessible to people living in city fringe areas. This will help in depopulating the Central Business District areas and optimization of real estate cost. Heavy Rail Based Metro Transit system has improved living conditions in Metropolitan cities. The High Capital Investment required for setting up a metro system necessitates the requirement of alternate Transit systems for Medium and smaller cities. This paper delves into this important area of suggesting an alternate urban transit model for Tier II and Tier III Indian cities. In this paper, modifications were suggested in the Metro Neo specification issued by the Ministry of Housing and Urban Affairs [10], to make it more cost-effective (to construct and maintain), agile, and with scope to harness new technologies as they become commercially viable in the future. Elevated or dedicated Busways with Full Diesel Hybrid Buses comprising an Energy Storage system (Li-ion battery pack) and a diesel power pack are suggested as the rolling stock for the transit system. This suggested rolling stock will be not only cost effective but also environmentally friendly. In the future, the Diesel Power Packs in the buses can be replaced with Hydrogen Fuel Cells or additional batteries to enable full electric and non-fossil fuel operation. The need for further research in developing cost-optimized structures in the Construction of viaducts and bus stations is felt and details in these areas have been highlighted. The suggested system will have the flexibility of a Bus Rapid Transit system and shall have some advantages of a metro system. Even in big cities with a full-fledged Metro system, the suggested modified Metro Neo system can act as a feeder system from faraway places. The paper proposes essential features of a transit system that is robust in present and is future-ready.

Full Battery and Hybrid Bus based Rapid Transit System as a Cost Effective Urban Transit Mode alternative to Metros in Tier II Tier III Indian Cities

Intra-city travel is a significant part of urban life and a fully functional intra-city transit system will help in reducing the number of private vehicles on the road, thus reducing pollution and traffic congestions. A robust urban transit system helps in the physical expansion of city limits, making education, job, and medical facilities accessible to people living in city fringe areas. This will help in depopulating the Central Business District areas and optimization of real estate cost. Heavy Rail Based Metro Transit system has improved living conditions in Metropolitan cities. The High Capital Investment required for setting up a metro system necessitates the requirement of alternate Transit systems for Medium and smaller cities. This paper delves into this important area of suggesting an alternate urban transit model for Tier II and Tier III Indian cities. In this paper, modifications were suggested in the Metro Neo specification issued by the Ministry of Housing and Urban Affairs [10], to make it more cost-effective (to construct and maintain), agile, and with scope to harness new technologies as they become commercially viable in the future. Elevated or dedicated Busways with Full Diesel Hybrid Buses comprising an Energy Storage system (Li-ion battery pack) and a diesel power pack are suggested as the rolling stock for the transit system. This suggested rolling stock will be not only cost effective but also environmentally friendly. In the future, the Diesel Power Packs in the buses can be replaced with Hydrogen Fuel Cells or additional batteries to enable full electric and non-fossil fuel operation. The need for further research in developing cost-optimized structures in the Construction of viaducts and bus stations is felt and details in these areas have been highlighted. The suggested system will have the flexibility of a Bus Rapid Transit system and shall have some advantages of a metro system. Even in big cities with a full-fledged Metro system, the suggested modified Metro Neo system can act as a feeder system from faraway places. The paper proposes essential features of a transit system that is robust in present and is future-ready.

Passengers' travel behavior before and after the adjustment of regular bus collinear sections: A case study in the incipient phase of metro operation in Xiamen

Increasing Chinese cities are constructing the metro transit system, which is considered an effective way to reduce urban traffic congestion and meet the rapid growth of travel demand. However, the operation of a new metro line typically coincides with the adjustment or cancellation of regular bus routes along the metro corridor. This paper evaluates the impact of the introduction of a new metro system on the travel mode choice of passengers in the collinear segment. Through longitudinal analysis using the travel data of the same integrated circuit (IC) card owners collected before and after the opening of the metro line, we study how passengers’ travel behaviors changed under a dual traffic environment in which a new metro line has been opened and the collinear bus has been adjusted. In this study, we selected travel distance, travel time difference, whether traveling during peak hours, and the number of colinear stations as independent variables to build a binary logic regression to find out the probability of regular bus collinear segment passengers choosing the metro in the above circumstance. The logistic model shows that mode switching occurs at the highest rate when a regular bus line shares four collinear stations with the metro and declines when the collinear section becomes longer or shorter. Further, the research results indicate that passengers on the collinear sections are more inclined to choose buses during rush hour. This study provides new evidence to better help transit agencies coordinate existing bus services and the new metro system.

Train Scheduling Method to Reduce Substation Energy Consumption and Peak Power of Metro Transit Systems

The rapid development of metro transit systems brings very significant energy consumption, and the high service frequency of metro trains increases the peak power requirement, which affects the operation of systems. Train scheduling optimization is an effective method to reduce energy consumption and substation peak power by adjusting timetable parameters. This paper proposes a train timetable optimization model to coordinate the operation of trains. The overlap time between accelerating and braking phases is maximized to improve the utilization of regenerative braking energy (RBE). Meanwhile, the overlap time between accelerating phases is minimized to reduce the substation peak power. In addition, the timetable optimization model is rebuilt into a mixed integer linear programming model by introducing logical and auxiliary variables, which can be solved by related solvers effectively. Case studies based on one of Guangzhou Metro Lines indicate that, for all-day operation, the utilization of RBE would likely be improved on the order of 23%, the substation energy consumption would likely be reduced on the order of 14%, and the duration of substation peak power would likely be reduced on the order of 66%.

Policy Zoning for Efficient Land Utilization Based on Spatio-Temporal Integration between the Bicycle-Sharing Service and the Metro Transit

Dockless bicycle-sharing is one of the novel transportation modes that emerged in recent years. As a component of the public transit system, it plays an important part in connecting the urban metro system but also generates some problems. With the low parking turnover rate, the oversupply of bicycles will generate parking demand and occupy a large amount of urban public land. To make the dockless bicycle-sharing service a more effective travel mode for connecting the metro system, it is necessary to implement policy zoning with different management strategies for efficient land utilization in the dockless bicycle-sharing system. In this paper, the bicycle-sharing trips data and the metro trips data are utilized to extract indexes to assess the connection performance and operation potential between the bicycle-sharing system and metro transit system. A methodology of coverage area division and policy zoning based on cycling attraction area areas is used. Applying the methodology proposed to a case study in Shanghai, the metro stations in Shanghai are classified into four clusters with different characteristics, including stations with effective land utilization, stations with the potential to promote BS service, stations with deficiencies in BS service, and stations with the potential to improve the land utilization efficiency. According to the different demand patterns and operation performance of the four clusters, corresponding policy suggestions are proposed.

Two‐step method to reduce metro transit energy consumption by optimising speed profile and timetable

With the rising energy prices and increasing environmental awareness, the energy efficiency of metro transit system has attracted much attention in recent years. This study proposes a two-step optimisation method to optimise speed profile and timetable, aiming to reduce the operational energy consumption of metro transit system. First, a coasting point searching algorithm is designed to reduce tractive energy consumption by optimising speed profile and running time distribution scheme. Then, a mixed-integer linear programming model is constructed to maximise the overlap time between the accelerating and braking phases by optimising headway and dwell time, in order to improve the utilisation of regenerative braking energy (RBE). Furthermore, numerical simulations are presented based on the data from a Guangzhou Metro Line. The results show that the tractive energy consumption can be reduced by 8.46% and the utilisation of RBE can be improved by 11.6%.

Joint optimization of delay-recovery and energy-saving in a metro system: A case study from China

Reducing delays in the metro transit system improves passenger satisfaction and the operational efficiency of the system. However, current delay-recovery strategies tend to reduce delays rather than the operational costs of the metro company. We propose optimized delay-recovery strategies to reduce the delay and increase energy efficiency simultaneously in this study. We classified delays in historical data according to the relationship between the delay time and the following headway, and we present optimized delay-recovery strategies for different initial delay conditions. A multi-objective optimization model was used to minimize the cumulative delay time (CDT) and energy consumption. We added weight factors to the objective functions to reflect the preferences of decision-makers regarding delay recovery and energy savings. We applied the non-dominated sorting genetic algorithm-II (NSGA-II) to solve the proposed model and verified its performance using a case study of the Chengdu Metro. The results showed that the proposed model exhibited excellent performance regarding delay recovery and energy savings.

3D Discrete Element Method Modelling of Tunnel Construction Impact on an Adjacent Tunnel

Closely-spaced side-by-side mechanized twin tunnels are commonly used in urban metro transit systems. The aim of this paper was to investigate the influence of tunnel construction on an adjacent existing tunnel using the 3D discrete element method (DEM) and propose a new method to protect the existing tunnel. The first tunnel at the left side was initially included in the DEM model. The construction of the second adjacent tunnel at the right side was then modelled in phases. Displacement, stress variation, porosity variation, and coordination of surroundings of the first tunnel were investigated. The results showed that the excavation of the second tunnel had a great negative impact on the existing tunnel surroundings when the distance of twin tunnels was less than the diameter of the tunnel. The maximum horizontal displacement occurred at the angle of 45° and was equal to 103 mm. The influenced area of the existing tunnel is the surroundings between the tunnel crown and the spring line on the second tunnel side near the tunnel lining. The composite reinforcement method consists of pasted fiber reinforced plastic (FRP) sheet method and grouting in a specific area; thus, the structure safety and the normal operation of the existing tunnel nearby can be guaranteed. The protective method can give reference for similar project.

Identifying critical nodes in metro network considering topological potential: A case study in Shenzhen city—China

How to identify critical nodes in metro networks is still an open and vital topic in complex networks, which has been a key issue in analyzing the structural organization of a network, especially in public transportation. Many effective measures have been developed to solve this problem in undirected or unweighted network. However, statistical indicators of static networks cannot reflect the spatial–temporal characteristics of passenger flow in the metro network. Furthermore, a single measure in critical nodes identification has its own shortcomings causing inaccurate estimation results. In this paper, a novel method for node significance on metro network based on Improved Topological Potential model considering Entropy (ITPE) is proposed. ITPE is utilized to aggregate the multi-measure by considering several different centrality measures to conduct the evaluation of node importance. In order to fully reflect the influence of nodes, topological entropy is adopted and applied to identify the weights of different centrality measures. In addition, invulnerability measurement is used to demonstrate the effectiveness of the proposed node identification method. Finally, the metro transit system in Shenzhen City, China was used as a case study to demonstrate the feasibility of the proposed method. It is found that ITPE method could effectively identify nodes or stations which are crucial both on network structure and passenger flow mobility while traditional undirected and unweighted network cannot completely identify. Accordingly, all the nodes estimated from ITPE method are ranked by the significance, and invulnerability is further used to test the rationality of the identification for critical nodes.

Evaluation of sustainable urban mobility using comparative environmental life cycle assessment: A case study of Qatar

The transportation sector is responsible for impacting both human health and greenhouse gas emissions. The primary mode of transport in Qatar is private automobiles, which can have a significant environmental impact. One strategy for transitioning to a low-carbon urban environment is the Doha Metro Project, which aims to reduce emissions from private automobiles. The focus of this study is the development of comparative life cycle assessment models to quantify the energy output and emissions of two major transportation alternatives in Qatar—automobiles and metro—within gate-to-gate system boundaries that limit their operations. GaBi 6.0 software was used to model and quantify the environmental impacts per functional unit of passenger kilometers traveled. The analysis demonstrates that public transportation is more sustainable in all impact categories compared with private automobiles. Most importantly, public transportation is key for addressing the critical environmental impacts of the transportation sector: climate change, particulate matter formation, human toxicity, terrestrial acidification, and water depletion. Annually, a public transportation metro line can reduce approximately 19.42 kt of CO2 emissions, 3.15 tonnes of PM 10 formation, 377.17 tonnes of 1,4-dichlorobenzene, 3.02 tonnes of nitrogen, 11.45 tonnes of sulfur dioxide, and 1.5 cubic meters of water. Electricity and water are the primary factors for the environmental impacts of the metro system; consequently, their impact can be further mitigated using cleaner renewable energy sources and through creation of strategic solutions to increase the use of the metro transit system.

Metro transit system resilience: Understanding the impacts of outdoor tracks and weather conditions on metro system interruptions

One of the main challenges facing transit agencies is offering reliable service with minimum number of interruptions and ensuing delays. Although this issue has recently emerged as a top priority in many cities to ensure sustainable social and environmental progress, there has been little research effort to investigate issues surrounding service disruption. As a response to this gap, this study aims at understanding the impact of outdoor track segments (or open-air sectors) of the metro system and weather conditions on the number of service interruptions and the magnitude of resulting delays at the stop level. The study uses detailed metro system interruption data collected in 2013 by the TTC, the public transit provider in the City of Toronto, Canada. Descriptive statistics and statistical models are developed for the purpose of the study. The empirical investigation reveals that outdoor tracks have a statistically significant association with metro system’s service interruptions. Longer outdoor track distances are linked to both higher frequencies and delays of service interruptions. Weather conditions, in terms of the amount of snow on the ground and rainfall interactions with outdoor tracks, have also a significant association with the frequency and duration of service interruptions. The paper results provide policy makers and planners with useful policy-relevant information related to the impact of outdoor tracks and weather conditions on the metro system interruptions that could be used to support higher capital investments when planning rail transit systems to achieve the system resilience.

The Application of Data Envelopment Analysis for Transportation Planning based on the Viewpoint of Economic Efficiency

There has been an ever increasing interest in the urban planning techniques, stimulated by the possibility that design strategies associated with the built environment be used well to control, manage, and shape individual behavior and socio-economic activity in cities. The numerous available evidence suggests that a combination of urban design strategies and Transit-Oriented Development (TOD) will help encourage our communities more livable, sustainable, and promoting the quality of our urban life. Therefore, the development of appropriate design techniques of TOD has become increasingly important as the TOD planning mode applied in the urban built environment. This study will try to integrate and classify the category of smart growth principles based on literature review. Followed by Fuzzy Delphi Technique (FDT) for obtaining expert’s opinions and screen the most important criteria of guiding principles. And then the empirical study of Taipei Metro Transit System will be demonstrated to show the application of our proposed methodology as well as framework. Finally, the adoption of Fuzzy Analytic Hierarchy Process (FAHP) method and Data Envelopment Analysis (DEA) model which combined with assurance region analysis will be applied to measure and select the most suitable MRT stations of Taipei Metro Transit System.

An integrated measure of accessibility and reliability of mass transit systems

The growth of a city or a metropolis requires well-functioning transit systems to accommodate the ensuing increase in travel demand. As a result, mass transit networks have to develop and expand from simple to complex topological systems over time to meet this demand. Such an evolution in the networks’ structure entails not only a change in network accessibility, but also a change in the level of network reliability on the part of stations and the entire system as well. Network accessibility and reliability are popular measures that have been widely applied to evaluate the resilience and vulnerability of a spatially networked system. However, the use of a single measure, either accessibility or reliability, provides different results, which demand an integrated measure to evaluate the network’s performance comprehensively. In this paper, we propose a set of integrated measures, named ACCREL (Integrated Accessibility and Reliability indicators) that considers both metrics in combination to evaluate a network’s performance and vulnerability. We apply the new measures for hypothetical mass transit system topologies, and a case study of the metro transit system in Seoul follows, highlighting the dynamics of network performance with four evolutionary stages. The main contribution of this study lies in the results from the experiments, which can be used to inform how transport network planning can be prepared to enhance the network functionality, thereby achieving a well-balanced, accessible, and reliable system. Insights on network vulnerability are also drawn for public transportation planners and spatial decision makers.

Two dimensional accessibility analysis of metro stations in Xi’an, China

Two important concepts of accessibility are proposed and measured in this paper: the attraction accessibility and the radiation accessibility. The attraction accessibility means the ease of reaching a given station by using certain modes of transport such as walking, bicycle, bus or taxi. The radiation accessibility represents the ease of reaching other stations from the given station. The metro transit system in Xi’an, China was used as a case study to elaborate the proposed concepts of accessibility. It has been found that the station attraction accessibility depends mainly on the walking connection accessibility, so the improvement of walking environment is a key factor in improving the station’s overall accessibility. The transfer stations exhibit the highest level of radiation accessibility while the first/last stations have the lowest. The radiation accessibility of other stations varies widely and depends on their location in the network and the topological depth from the transfer stations. In general, the closer to the middle of the line, the higher the radiation accessibility, whereas the closer to the end of the line, the lower the accessibility. The findings provide decision makers with evidence on how to improve the metro stations’ travel environment and the layout of the metro network.

The effects of the integration of metro station and mega-multi-mall on consumers’ activities: a case study of Shanghai

Abstract With large scale development of metro transit systems in many mega cities in China, the advantages of the integration of metro station areas and mega-multi-mall (IMSM) has been widely recognized. This study is designed to understand the effects of IMSM project on consumers’ travel behavior by weekday/weekend to provide insights for integrated land use and transportation planning. A questionnaire survey of Wujiaochang Wanda Mall in Shanghai is conducted on consumer activity, followed by the information from the survey to summarize the effects of IMSM on the consumer travel range and the consumer's own properties. Then the research focuses on the effects of IMSM on consumer demand. Finally, the influence factors of consumer consumption, and the influence factors of consumer travel mode are studied through the correlation analysis. The purpose of this research is to solve several questions: 1. whether the IMSM will stimulate consumption? 2. What is the relationship between consumer characteristics and different consumer activities? 3. What is the influence of IMSM on consumer consuming and travelling activities?

System energy optimisation strategies for metros with regeneration

Energy and environmental sustainability in transportation are becoming ever more important. In Europe, the transportation sector is responsible for about 30% of the final end use of energy. Electrified railway systems play an important role in contributing to the reduction of energy usage and CO2 emissions compared with other transport modes. For metro-transit systems with frequently motoring and braking trains, the effective use of regenerated braking energy is a significant way to reduce the net energy consumption. Although eco-driving strategies have been studied for some time, a comprehensive understanding of how regeneration affects the overall system energy consumption has not been developed. This paper proposes a multi-train traction power network modelling method to determine the system energy flow of the railway system with regenerating braking trains. The initial results show that minimising traction energy use is not the same as minimising the system energy usage in a metro system. An integrated optimisation method is proposed to solve the system energy-saving problem, which takes train movement and electrical power flow into consideration. The results of a study of the Beijing Yizhuang metro line indicate that optimised operation could reduce the energy consumption at the substations by nearly 38.6% compared to that used with the existing ATO operation.