Transition Operator Research Articles

Public Transport Tweets in London, Madrid and Prague in the COVID-19 Period—Temporal and Spatial Differences in Activity Topics

Public transport requires constant feedback to improve and satisfy daily users. Twitter offers monitoring of user messages, discussion and emoticons addressed to official transport provider accounts. This information can be particularly useful in delicate situations such as management of transit operations during the COVID-19 pandemic. The behaviour of Twitter users in Madrid, London and Prague is analysed with the goal of recognising similar patterns and detecting differences in traffic related topics and temporal cycles. Topics in transit tweets were identified using the bag of words approach and pre-processing in R. COVID-19 is a dominant topic for both London and Madrid but a minor one for Prague, where Twitter serves mainly to deliver messages from politicians and stakeholders. COVID-19 interferes with the meaning of other topics, such as overcrowding or staff. Additionally, specific topics were discovered, such as air quality in Victoria Station, London, or racism in Madrid. For all cities, transit-related tweeting activity declines over weekends. However, London shows much less decline than Prague or Madrid. Weekday daily rhythms show major tweeting activity during the morning in all cities but with different start times. The spatial distribution of tweets for the busiest stations shows that the best-balanced tweeting activity is found in Madrid metro stations.

Simultaneous description of β decay and low-lying structure of neutron-rich even- and odd-mass Rh and Pd nuclei

The low-energy structure and $\beta$ decay properties of neutron-rich even- and odd-mass Pd and Rh nuclei are studied using a mapping framework based on the nuclear density functional theory and the particle-boson coupling scheme. Constrained Hartree-Fock-Bogoliubov calculations using the Gogny-D1M energy density functional are performed to obtain microscopic inputs to determine the interacting-boson Hamiltonian employed to describe the even-even core Pd nuclei. The mean-field calculations also provide single-particle energies for the odd systems, which are used to determine essential ingredients of the particle-boson interactions for the odd-nucleon systems, and of the Gamow-Teller and Fermi transition operators. The potential energy surfaces obtained for even-even Pd isotopes as well as the spectroscopic properties for the even- and odd-mass systems suggest a transition from prolate deformed to $\gamma$-unstable and to nearly-spherical shapes. The predicted $\beta$ decay $\log{ft}$ values are shown to be sensitive to the details of the wave functions for the parent and daughter nuclei, and therefore serve as a stringent test of the employed theoretical approach.

An agent-based fleet management model for first- and last-mile services

With the growth of cars and car-sharing applications, commuters in many cities, particularly developing countries, are shifting away from public transport. These shifts have affected two key stakeholders: transit operators and first- and last-mile (FLM) services. Although most cities continue to invest heavily in bus and metro projects to make public transit attractive, ridership in these systems has often failed to reach targeted levels. FLM service providers also experience lower demand and revenues in the wake of shifts to other means of transport. Effective FLM options are required to prevent this phenomenon and make public transport attractive for commuters. One possible solution is to forge partnerships between public transport and FLM providers that offer competitive joint mobility options. Such solutions require prudent allocation of supply and optimised strategies for FLM operations and ride-sharing. To this end, we build an agent- and event-based simulation model which captures interactions between passengers and FLM services using statecharts, vehicle routing models, and other trip matching rules. An optimisation model for allocating FLM vehicles at different transit stations is proposed to reduce unserved requests. Using real-world metro transit demand data from Bengaluru, India, the effectiveness of our approach in improving FLM connectivity and quantifying the benefits of sharing trips is demonstrated.

Dynamic Multiline Vehicle Dispatching Strategy in Transit Operations

Providing regularity in buses’ operation in high-frequency services is essential to offer a good quality of service to users. If buses are not dispatched at regular headways from the terminal, headway irregularity will gradually increase along the line. In this work, we study a vehicle dispatching problem in which multiple lines start their operations from a common terminal where buses can interchange between lines. The model simultaneously decides the ideal dispatching headway for each line and assigns the following arriving buses to the terminal its line to operate and its corresponding dispatching time. The objective is to minimize the dispatching interval’s deviation from an ideal headway that is dynamically updated based on the system’s status. We formulate our problem as a Mixed-integer quadratic problem and adopt a rolling horizon policy to cope with the dynamic and stochastic environment of public transit systems. We prove that a bus assignment that satisfies the FIFO discipline is an optimal solution for the proposed problem. We evaluate our model in a simulation environment under different operational conditions and study the incremental benefits of allowing different flexibility schemes. Our results show that a full flexibility scheme where buses can freely interchange between lines reduces the coefficient of variation of dispatch headways and improves frequency compliance by nearly 20% when compared with the case where buses are restricted to operate in a single line. It also outperforms a myopic heuristic that adopts a a priori target headway. Computational times are compatible with real-time applications.

Resilience Assessment of an Urban Rail Transit Network Under Short-Term Operational Disturbances

Operational disturbances within 30 min, namely, short-term operational disturbances (STODs), occur frequently during the daily operation of an urban rail transit (URT) system. Therefore, there is an urgent need to assess a network’s ability to respond to STODs to improve its operational level. The resilience of a URT network jointly considering turn-back operations, the occurrence time of STODs, and passenger travel experience is addressed. By considering passenger travel alternatives under STODs, we assessed the resilience of a network by utilizing the ratio of the average loss of a time-dependent performance indicator, which is referred to as the operational service level indicator in this paper. A simulation-based resilience assessment flowchart is also proposed. Numerical experiments conducted on the Chengdu subway network indicate that this network is more resilient to successive station failure than to simultaneous failure. Guaranteeing the normal operation of transfer stations is vital for enhancing the resilience of a network. The metric proposed in this paper is more practical for assessing resilience than the two commonly used metrics (performance loss and disturbance duration). Additionally, the experimental results highlight that turn-back operations at the stations have a significant impact on the resilience of a URT network. The sensitivity analysis of the parameters indicates that ensuring the normal operation of links connected by critical stations, preventing large-scale station failure, improving passenger tolerance to disturbance durations, and restoring the connectivity of disrupted links rapidly have practical significance for enhancing the resilience of a network.

Improved LSTM-Based Time-Series Anomaly Detection in Rail Transit Operation Environments

Anomaly detection is crucial to the reliability and safety of rail transit systems. The rapid development of Internet of Things (IoT) and cloud technologies together with recent advances in machine learning offered various cloud-based data-driven approaches to automatic anomaly detection. However, the challenges introduced by the different types of equipment in rail transit systems with highly diverse data distributions and the lack of labeled anomaly data have not been sufficiently addressed. In this article, we attempt to cope with such challenges by proposing an improved long short term memory (LSTM)-based time-series anomaly detection scheme. The key elements of the proposed scheme include an improved LSTM model that may achieve more accurate time-series prediction for various rail transit devices and a method for determining an appropriate error threshold for detecting anomalies based on the prediction errors. In order to further enhance anomaly detection performance, we also propose a pruning algorithm for reducing the number of false anomalies. Our method does not rely on scarce anomaly labels but dynamically determines a threshold of prediction errors to identify anomalies; therefore, it overcomes the challenge of the extremely uneven distribution of rail transit data. We conducted extensive experiments in a real metro operation environment for performance evaluation. The experiment results prove the effectiveness of the proposed scheme and show a superior performance of the scheme compared to existing anomaly detection methods.

Transit system and benefits of its operation

After the end of the Second World War, there was a rapid increase in trade in goods in Europe. Due to the long and complicated customs procedures every time the goods crossed the border, the trade procedures were complicated. All this was aimed at drawing up an international agreement, which should contribute to the creation of a free trade space. Border infrastructure is an important element in reducing border congestion. Inadequate infrastructure is often a major obstacle to establishing efficient transit, even if customs procedures are streamlined and efficient. Smooth movement of transit cargo requires quality infrastructure. When transit documents are  already issued in advance, truck drivers can use designated "transit lanes" and remain in their vehicles. Transit operations necessarily include various regulatory requirements imposed by government agencies other than customs.

Calculations of the np→dγ reaction in chiral effective field theory

We present a calculation of the radiative capture cross section $p(n,\gamma )d$ in the low-energy range, where the $M1$ reaction channel dominates. Employing the LENPIC nucleon-nucleon interaction up to the fifth order (N4LO) that is regularized by the semi-local coordinate space regulators, we obtain the initial and final state wave functions, and evaluate the phase shifts of the scattering state and deuteron properties. We derive the transition operator from the chiral effective field theory up to the next-to-next-to leading order (N2LO), where we also regularize the transition operator using regulators consistent with those of the interactions. We compute the capture cross sections and the results show a converging pattern with the chiral-order expansion of the nucleon-nucleon interaction, where the regulator dependence of the results is weak when higher-order nucleon-nucleon interactions are employed. We quantify the uncertainties of the cross-section results due to the chiral-order truncation. The chirally complete and consistent cross-section results are performed up to N2LO and they compare well with the experiments and other theoretical predictions.

Land Premium Effects of Urban Rail Transit and the Associated Policy Insights for TOD: A Case of Ningbo, China

With considerable investments, mainly from local government budgets, the construction and operation of urban rail transit (URT) can exert significant spillover effects on the surrounding land use and land prices. In particular, China’s local governments are actively committed to developing their URT systems and promoting large-scale transit-oriented development (TOD) projects under the public land leasing policy. However, the connection between the land premium effects and TOD policy and practice is still lacking, particularly in the local government contexts, which exhibit significant policy and spatial heterogeneity. Thus, this research represents an attempt to better address this issue using the city of Ningbo as a case study. First, the premium effects of URT on land prices are examined, after which three crucial policy insights (land value capture [LVC], public–private cooperation [PPC], and urban regeneration) are proposed to enhance the effectiveness and efficiency of TOD, demonstrating its strong connection with the potential premium effects. The findings demonstrate that (1) local governments have adopted different innovative policies—with the ambition—to implement LVC; (2) assisted by PPC, the local rail transit authority can significantly amplify the premium effects, although it must still address the fair distribution of premiums across multiple stakeholders; and (3) transit-oriented urban regeneration can significantly influence land prices/land rents and subsequently generate significant gentrification, which will be further addressed by the TOD policy and practice.

Transfer station choice in a multimodal transit system: An empirical study

Connectivity between modes and lines constitutes a core aspect for multimodal transport system user experiences. Using a large-scale transit smart card dataset, we reveal transfer station choices in bus–rail intermodal trips frequently deviate from the “nearest-station” heuristics, motivating research to better explain real transfer behaviors and define more realistic station catchment areas. The investigation is centered on modeling transfers from bus to rail using multinomial logistic regression discrete choice models applied to 200k observations from four weeks of transit smart card observations. The results show that: (1) for trips requiring an intermodal transfer, riders select the nearest rail station in only 40% of cases; (2) commuters’ transfer station selections are jointly influenced by the trip attributes of all involved modes, with the bus ride distance contributing the most, followed by the walking distance; and (3) commuters’ sensitivity to travel distances exhibits nonlinear trends: sensitivity to bus ride distance dampens gradually as a function of trip length, while the sensitivity to walking distance exhibits a concave shape peaking at around 0.6 km. Catchment area modeling reveals that (4) location attributes (e.g., distance from the city center) play a greater role in defining the station catchment area than other attributes (e.g., land use and built environment). Specifically, the catchment area radius is larger for stations located further away from the city center or from the nearest interchange station. Moreover, (5) stations with more amenities (e.g., higher density of shops and greater accessibility) are likely to attract commuters from a larger area. This study strengthens the connections between station selection patterns and station catchment area analysis, to better guide intermodal transit design and operations, such as improving predictions of passenger flows at transfer stations.

The Puzzle of Income, Race, and Density: Preliminary Evidence on Transit Use from the 1991 American Housing Survey

The article presents the results of a preliminary analysis of transit ridership data from the 1991 American Housing Survey. The findings suggest that transit operators may find new markets in places they had not thought to look: among high income travelers, including high income minority travelers.

A New Customer Satisfaction Index for Evaluating Transit Service Quality

In this paper, an index based on customer perspective is proposed for evaluating transit service quality. The index, named Heterogeneous Customer Satisfaction Index, is inspired by the traditional Customer Satisfaction Index, but takes into account the heterogeneity among the user judgments about the different service aspects. The index allows service quality to be monitored, the causes generating customer satisfaction/dissatisfaction to be identified, and the strategies for improving the service quality to be defined. The proposed methodologies show some advantages compared to the others adopted for measuring service quality, because it can be easily applied by the transit operators.

Bus Transit Service Planning and Operations in a Competitive Environment

Transit services are currently facing several challenges in the United States and around the world. For many reasons, among which the fluctuations in gas prices and the state of the economy are the major ones, transit demand has noticed a considerable increase. The challenge that transit agencies are facing is to make these increases permanent by maintaining transit’s competitive edge over the private vehicle with more dense and reliable service. Current methodologies for scheduling new as well as improving existing transit routes should be able to respond to the dynamic nature of urban traffic as it is evolving through ITS and more comprehensive traffic management strategies. In this research paper, we correlate travel time obtained from buses to travel time obtained from floating vehicles in the Twin Cities metropolitan region. This research helps to introduce more reliable estimates of travel time for planning new and competitive transit services. Specifically, this work studied two bus routes over a variety of different roadway types and traffic conditions and produced statistical models that can estimate travel time based on measurements collected from buses and regular vehicle probes. The generated models revealed the characteristics causing bus service to be generally slower. Altering bus route characteristics can reduce overall travel time and minimize the travel time disparity between buses and private vehicles. In particular, the models presented in this paper lend support to bus-only shoulder policies, stop consolidation, serving major streets with fewer stop signs, and implementation of smart transit signal priority.

Electric Bus Scheduling and Timetabling, Fast Charging Infrastructure Planning, and Their Impact on the Grid: A Review

Transit agencies are increasingly embracing electric buses (EB) as an energy-efficient and emission-free alternative to the conventional bus fleets. They are rapidly replacing conventional buses with electric ones. As a result, emerging challenges of electrifying public transportation bus networks in cities should be addressed. Introducing electric buses to the bus transit system would affect the public transit operation planning steps. The steps are network design, timetabling, bus scheduling, and crew scheduling. Regarding the functional and operational differences between conventional buses and electric buses, such stages should be changed and optimized to enhance the level of service for the users while reducing operating costs for service providers. Many mathematical optimization models have been developed for conventional buses. However, such models would not fit the electric buses due to EBs’ limited traveling range and long charging time. Therefore, new mathematical models should be developed to consider the unique features of electric buses. We present a comprehensive literature review to critically review and classify the work done on these topics. This paper compares the studies that have been done in this field and highlight the missing links and gaps in the considered papers, and the potential future studies that could be done. The considered papers cover the integration of timetabling and vehicle scheduling, recharging scheduling planning, and fast charging infrastructure location planning and its impacts on the grid. The main goal of this research is to highlight the research gaps and potential directions for future studies in this domain to encourage more realistic and applicable models and solution approaches for fully electric bus transit systems.

GIS-Based Support System for On-Demand Flexroute Transit Service

Geographic Information Systems (GIS) are a proven resource for public transportation service planning and evaluation. In particular, their spatial analysis and database management capabilities make them well suited for such applications. The primary cost incurred in a GIS application is for the development and maintenance of high-quality spatial databases. Due to this cost, public transportation agencies want to utilize these databases to support a wider array of applications. As desktop GIS software and computer hardware become more powerful, GIS can be used to develop applications for “real-time “ operations. In this research effort, a GIS-based prototype system was developed and tested to support the scheduling and dispatch functions of an on-demand flexroute transit service. The effectiveness of the prototype demonstrates the potential of GIS to support time-critical transit operations.

Automatic Vehicle Location and Computer-Aided Dispatch Systems: Design and Application Considerations

Automatic Vehicle Location (AVL) systems can track transit vehicles in real time. Computer-Aided Dispatch (CAD) software is used to monitor transit operations and assist management of transit operations. Together with AVL systems, CAD software can be used to replace a disabled vehicle by dispatching another vehicle, or meet fluctuating travel demand by adjusting transit headways, schedules, and routes. AVL and CAD technologies can vitalize transit by directly improving on-time performance, increasing transit efficiency through providing dispatchers with location, direction and status information, and reducing operating costs through reducing dependence on transit field supervisory personnel. Direct benefits to travelers can include higher reliability of travel times and reduced stress in dealing with transit unreliability. This study explores the development, availability, and impacts of AVL/CAD technologies as reported by AVL vendors and transit implementers. The study defines the key features, functions, and performance characteristics of AVL/CAD technologies that can influence the level of benefits realized. The AVL/CAD implementation context is explored by examining where, when, and for what users these systems are being implemented. The results of two surveys are reported. To explore the availability of AVU CAD systems, technology suppliers were surveyed. Suppliers identified the features, functions, and performance of available AVUCAD technologies. To determine the extent of AVL/CAD deployment, transit operators were surveyed regarding their experiences with AVL/CAD technologies and the subsequent impacts on travelers and transit agency performance. This research provides a systematic method for evaluation of AVL/CAD systems and reports the perceptions of AVL/CAD vendors and transit implementers regarding available products and their impacts. The results suggest a need for better tools to characterize and quantify the impacts and benefits of AVU CAD systems.

Measuring Service Quality in Scheduled Bus Services

Transit operators are increasingly being asked to provide services more cost efficiently. To do this, operators must find ways to reduce the costs of delivering a given level of service (in contrast to simply reducing cost at the expense of lower service levels). There is growing concern in many countries that operators are not focusing enough attention on identifying whether passengers are satisfied with existing service levels and what might be done to increase or at least preserve current service quality.This article develops a stated preference model of service quality choice that provides the set of indicators required to represent a user-based measure of service quality. The service quality index (SQI) provides an operationally appealing measure of service effectiveness to assist regulators in administering and monitoring a performance assessment regime and operators in improving customer service. SQI has been readily accepted by many bus operators in New South Wales (Australia) as the preferred way of establishing and monitoring the effectiveness of service levels, in contrast to traditional stand-alone satisfaction scores based on independent assessment of each attribute in isolation from the entire service package that passengers actually experience.

Detection Range Setting Methodology for Signal Priority

A significant amount of delay to transit vehicles in urban areas is caused by traffic signals. Implementation of signal priority has the potential to reduce control delay caused by traffic signals. The implementation of these systems requires engineering studies that address both transit and traffic signal operations. A comprehensive program requires coordination between the transit agency and the transportation department to address needs of both agencies and users. The City of Portland and the Tri-County Metropolitan Transportation District of Oregon (Tri-Met) have been working on a program that exhibits the elements of such an effort. This article details the efforts of the project and the methodology for developing signal timing and detection distance settings.

Facing Societal Challenges: The Need for New Paradigms in Rural Transit Service

In response to major societal trends, rural transit operators should consider different ways to organize, design, and deliver public transit services. This article summarizes societal changes affecting rural areas and identifies five “new paradigms” in rural service organization and delivery to meet the needs created in many rural areas. The article concludes that many operators in a variety of rural settings could enhance their role and better meet the transportation challenge of a changing population by adopting different service paradigms.

Performance-Based Transit Operating Subsidy Allocation: A Before and After Study

Transit operating subsidy allocation procedures based on such factors as deficit or population have been under attack ever since operating subsidy became widespread in the 1970s. These procedures do not directly provide any incentive for innovation, cost cutting strategies, and efficient operation. Recognizing the problems associated with a 100 percent population-based formula, the State of Indiana, since 1986, has used transit performance as a part of its subsidy allocation procedure. This paper examines the impact of this procedure on transit system self-reliance, efficiency, and effectiveness by analyzing the relevant data between the periods before and after the procedure was instituted. The results show that the procedure has positively affected transit system performance, particularly for small- and medium-sized properties. The largest positive change has been realized in transit system effectiveness and self-reliance, while no perceptible change was observed in transit system efficiency.