Monash University, Institute of Transport Studies: World Transit Research (WTR)
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Enhancing rail safety through real-time defect detection: A novel lightweight network approach
No full textThe rapid detection of internal rail defects is critical to maintaining railway safety, but this task faces a significant challenge due to the limited computational resources of onboard detection systems. This paper presents YOLOv8n-LiteCBAM, an advanced network designed to enhance the efficiency of rail defect detection. The network designs a lightweight DepthStackNet backbone to replace the existing CSPDarkNet backbone. Further optimization is achieved through model pruning techniques and the incorporation of a novel Bidirectional Convolutional Block Attention Module (BiCBAM). Additionally, inference acceleration is realized via ONNX Runtime. Experimental results on the rail defect dataset demonstrate that our model achieves 92.9% mAP with inference speeds of 136.79 FPS on the GPU and 38.36 FPS on the CPU. The model’s inference speed outperforms that of other lightweight models and ensures that it meets the real-time detection requirements of Rail Flaw Detection (RFD) vehicles traveling at 80 km/h. Consequently, the YOLOv8n-LiteCBAM network is with some potential for industrial application in the expedited detection of internal rail defects
Encounter Network and Its Application to Studying Epidemic Spread through Public Transportation Networks
No full textEpidemic diseases have always been a challenging issue in public health. Densely populated urban public transportation systems could be the perfect candidate for transmitting epidemics by direct contact with the infected population and contaminated surfaces. In network analysis, betweenness centrality (BC), as the primary metric, has been used to measure an individual’s communication in the network. This research uses this concept to measure the risk of transmitting disease in public transportation links. For each network node, the set of shortest paths from that node to all other nodes compose a shortest paths sub-graph (tree). Source node total betweenness centrality (TBC) is defined as the sum of BC of all edges of this tree. Similarly, the shortest path sub-graph consisting of the set of the shortest paths from all nodes to a single target node is considered, and the target node TBC is defined as the sum of BC of all edges of this tree. The node encounter matrix is also defined to measure each node pair encounter in the network. The source node TBC of a node depicts the risk of transmitting the disease from that node to other nodes. Conversely, the target node TBC of a node is related to the risk of transmitting the disease from other nodes to that node. The susceptible-infected model is used to evaluate the proposed method by measuring the number of infected nodes
“Co-Opetition” Effects of Ride-Hailing on Metro Services and its Spatially Varying Determinants: Evidence from Shanghai, China
No full textThe rapid expansion of ride-hailing services has sparked intensive debate on their competition and cooperation with public transit such as metro systems. However, empirical evidence on such “co-opetition” effects remains limited, as well as on their spatiotemporal characteristics and influencing factors. To address this gap, we developed a three-level framework for detecting the co-opetition effects of ride-hailing on metro services based on ride-hailing trip data from Shanghai in China. We then performed exploratory analysis to reveal the spatiotemporal patterns of these effects. Lastly, we employed Poisson regression models to assess the impact of trip characteristics, the built environment, and socioeconomic indicators on various co-opetition effects. The results show that: 1) the co-opetition effects of ride-hailing on metro services exhibit distinct temporal patterns, with the complementary effect predominantly occurring during the initial morning peak hours, while the substitution effect is more prominent toward the end; 2) ride-hailing tends to substitute primarily for metro services in the city center, while complementing and supplementing them in the suburban areas; 3) the density of metro facilities is negatively associated with the supplementary effect and potential complementary effect; 4) the potential complementary effect can be categorized as front-end and back-end connections, with front-end connections being more susceptible to the density of facilities at the trip origin, while the back-end connections are influenced by the density at the destination; and 5) travel distance and road congestion demonstrate a negative correlation with the substitution effect, whereas road network density exhibits a positive correlation
Toward a Better Understanding of the Construction Impacts of a Light Rail System in Montréal, Canada
No full textLarge-scale transport infrastructure projects generate long-lasting changes in the built environment and alter the lives of nearby residents. It is crucial to understand public perceptions of public-transit projects and associated construction impacts, as they influence the social acceptance and eventual success of such projects. To characterize the construction-phase experiences of a new light rail in Montréal, Canada—the Réseau express métropolitain (REM)—we analyzed data from 1,236 respondents from the Greater Montréal region who self-reported ongoing construction activities near their homes. This study employs an exploratory factor and k-means cluster analysis to group residents by their different experiences and perceptions of the REM and its associated construction impacts. The analysis returned five clusters with distinct construction experiences: construction-concerned travelers, REM-critical respondents, neutral travelers, REM enthusiasts, and rerouted travelers. Subsequently, the acceptability of the impacts during the construction phase on each cluster is assessed by comparing perceptions of the impact of neighborhood change on their quality of life and their intention to use the REM. Finally, we derive targeted policy recommendations to help promote increased social acceptability of light-rail transit (LRT) projects, including mitigating disruptions in construction zones, public information campaigns, and inclusive decision-making processes. Findings from this study can benefit policymakers and transport planners as they aim to reduce the disruptions associated with the construction of LRT systems and promote increased social acceptability
Incorporating a Public Transit Equity Lens in Evacuation Planning
No full textDisasters caused by extreme weather and human-initiated events continue to disproportionately affect vulnerable and underserved communities. Although these communities often rely on public transit to travel, most North American jurisdictions still lack a fundamental understanding of equity-centered needs or evacuation plans that incorporate public transit use. Consequently, this study conducted a community-centered methodology with eight focus groups in February 2023 among historically underrepresented groups in evacuation planning. Comprising 52 participants in Edmonton, Alberta, the groups included carless residents, people with disabilities, older adults, lower-income households, racial and ethnic minorities, recent immigrants, parents/guardians of young children, and women. Thematic analysis of the focus group data was performed using MAXQDA. Participants identified challenges and concerns related to public transit costs, possible overcrowding, and inadequate assistance services for people with disabilities and the medically fragile during evacuations. The focus groups largely looked to emergency management offices and transportation agencies to ensure public transit reliability, affordability, and accessibility. Surprising references were also made to public transit as a potential tool for building community cohesion and reducing sentiments of anxiety during disasters. Finally, we found that each group had specific insights based on their vulnerability. For example, whereas lower-income households prioritized increased frequency of transit services during emergencies, older adults called for trained medical staff and accessibility features. We offer several policy recommendations to enhance both resilient and equitable evacuation planning
Modal Splits Before, During, and After the Pandemic in Switzerland
No full textThe MOBIS-Covid data provides a unique opportunity to put mobility adjustments observed during the crisis in perspective. A large panel has been tracked from before the crisis up until the end of 2022. Starting with 1370 participants and observing a gradual drop-off, around 250 kept tracking throughout the whole study period of over 2 years. Switzerland lifted its measures counteracting the virus spread in mid-February 2022, reaching a potential new equilibrium in the months after. Descriptive indicators have been constructed for Switzerland in order to disentangle the narrative of the crisis from the perspective of transport demand. The descriptive findings are supplemented by a mixed multiple discrete-continuous extreme value model (MMDCEV). We find a shift in modal splits away from car and train, where in particular bus could expand its mode share. While the cycling and walking booms were temporary, the bicycle still shows slightly higher mode distance shares. There are observable differences between the working arrangements (home office, mixture and in-office), however, we do not find evidence that preferences differ substantially. This suggests that the working arrangement segments the population along socioeconomic dimensions with different mobility behaviors and mode preferences. Modes are more satiated in the post-pandemic world, hinting that people use fewer modes in their weekly modal mix but use them more intensely. However, the model suggests that the pandemic should not be read as a structural break in mode preferences. We will therefore likely see further convergence to the pre-pandemic equilibrium
Imagine the financial barrier to public transport use disappears. The impact of the 9-Euro-Ticket on the mobility and social participation of low-income households with children
No full textFrom June to August 2022, the financial barrier to public transport use almost completely disappeared in Germany due to the 9-Euro-Ticket. It enabled anyone with access to public transport infrastructure across Germany to use public transport for 9 euros per person per month. As this completely changed the conditions for public transport use, especially for low-income households with children, the following research questions arise: (1) what effect does the 9-Euro-Ticket have on the travel practices and social participation of low-income households with children? (2) how and by what were the travel practices shaped by the 9-Euro-Ticket? and (3) what happened to the interviewees’ travel practices after the measure expired? To answer these questions, twelve qualitative interviews were conducted with low-income households with children in the Hanover region.
This study found that the 9-Euro-Ticket removed the financial constraint of public transport use, changed the travel practices of most interviewees and had a wide range of positive meanings. The respondents associate the 9-Euro-Ticket with freedom, joy at being able to offer their children something, along with financial and psychological relief. Additionally, the 9-Euro-Ticket enabled the interviewees to engage in leisure activities, to visit relatives, contributed to integration, had an empowering effect, especially for women and children, and thus represents a measure to increase social participation. After the three months of the 9-Euro-Ticket, financing public transport use challenges low-income households again and financial constraints prevent them from reaching certain places and engaging in out-of-home activities
A sustainable battery scheduling and echelon utilization framework for electric bus network with photovoltaic charging infrastructure
No full textBattery capacity degradation in battery electric buses (BEBs) poses a significant operational challenge for transit agencies. This study presents a sustainable battery scheduling and echelon utilization framework considering battery capacity fading and charging infrastructure integrated with solar photovoltaic (PV) and energy storage systems. The framework aims to minimize the sum of bus charging, battery replacement, and carbon emission costs during the BEB lifespan. We first present a power battery replacement problem for a single bus fleet, then extend it to a joint power battery replacement and fleet-depot matching problem. Finally, we propose a power battery replacement and fleet-depot problem by introducing solar PV and energy storage systems. Dynamic programming, Lagrange relaxation, and a two-step approach are adopted to solve the three problems. A case study involving six bus depots in Beijing demonstrates that optimal battery replacement schedules can significantly lower charging costs. Moreover, integrating solar PV and energy storage is shown to considerably reduce both charging costs and carbon emissions
COVID-19 and the demand for transit access: Residential real estate prices in the Tokyo metropolitan area
No full textTo better understand the spatial implications of the COVID-19 pandemic on demand for both housing and transportation, this analysis examines sales price data from condominiums in the Tokyo metropolitan area. Demand for high-access condominiums—both those near transit stations and those in close proximity to the city center—was strong throughout the study period (2017–2022), and showed neither a positive nor negative association with the onset of the pandemic. Price growth for lower-access properties—those further from transit stations and those in peripheral suburban locations—was, by contrast, far more robust during the COVID era than in the pre-pandemic period. Results suggest that COVID-related changes in travel behavior—particularly the decreased commute burden associated with remote work—may have made lower-access locations more attractive to home buyers. This has not, however, tempered demand for properties near transit and in the central city, which remained strong throughout the pandemic period
Differences in commuting between employee and self-employed workers: The case of Latin America
No full textCommuting time represents a shock to worker time allocations that ultimately affects wellbeing. This paper analyzes the commuting behavior of employee and self-employed workers in urban areas of eleven Latin American countries. Using data from the ECAF data, results show that employees spend about 8.2 more minutes commuting to work than their self-employed counterparts, net of observable characteristics, a difference of around 18.5% of the employees\u27 commuting time. This difference is qualitatively robust across the eleven countries and is concentrated in commutes by public transit, but is not explained by differences in access to public transit services. This analysis is a first cross-country exploration of self-employed and employee workers\u27 commuting time in Latin America. By analyzing differences in commuting time between these two groups of workers, our analysis may serve to guide future planning programs