ANNUAL CONGRESS 2025

Where do different income groups encounter each other? Assessing the impact of new metro lines on income-based activity-space segregation

Not scheduled

20m

Yildiz Technical University, Istanbul

Oral Track 17 | PUBLIC SPACE

Speaker

Ms Haoran Li (Tongji University)

Description

With the rapid urbanization and increasing population mobility, cities worldwide are facing severe challenges related to segregation and inequality (Florida, 2017). A diverse population composition is vital for fostering social cohesion within urban areas (Moro et al., 2021). Income segregation, stemming from the uneven spatial distribution of income groups, could profoundly undermine urban residents' equitable access to amenities and resources (Lees et al., 2013). This phenomenon manifests not only as static residential segregation tied to housing disparities (Wong and Shaw, 2011), but also as dynamic segregation in daily activity spaces. Such activity-space based segregation may impede spatial integration among diverse groups (Wang et al., 2012), utterly eroding urban vitality.

In recent decades, the rapid expansion of urban rail transit networks has not only significantly enhanced urban mobility, but also exert profound influences on regional economies and social structures. Urban rail transit provides residents with a more efficient and sustainable travel option and reshapes the spatial distributions of income groups by altering urban economic activities and population flows, thus potentially affecting the income segregation within activity spaces (Deng and Zhao, 2022). Some research posits that rail transit development could accelerate gentrification, exacerbating wealth disparities, and intensifying income-based activity space segregation (Heilmann, 2018). Conversely, other studies highlight the potential for public transport infrastructure to improve urban mobility and accessibility, thereby alleviating income segregation and fostering social integration (Loo et al., 2024). Nevertheless, the causal mechanisms driving these impacts remain unclear, highlighting the need for further investigation.

To address the research gaps, the study aims to answer the following three research questions using Shanghai, China as a case study:
1) How does the opening of new metro lines affect income-based activity-space segregation?
2) How does the new metro opening influence daily activities of different income groups across the temporal and spatial dimensions?
3) Do the metro effects show heterogeneity across metro stations and urban locations?

Shanghai, a key economic and financial hub in China, faces pronounced challenges related to urban social spatial segregation. In this study, we leverage a large-scale mobile signaling dataset for millions of users and difference-in-differences (DID) models to analyzes the causal impact of the inauguration of Shanghai Metro Line 15 on income-based activity space segregation and its heterogeneity across income groups and urban locations. Preliminary research results indicate that opening of new metro lines can foster the encounter and interaction of different income groups, thus mitigating the activity-space segregation. Specifically, the opening of Metro Line 15 has reduced the dominating concentration of low-income individuals in the station areas in pre-opening period, while increasing the visiting frequency and duration of the low-to-middle-income group. Moreover, the findings suggest that the opening of metro lines may have initiated an early-stage gentrification effect.

The study provide useful insights into the social equity implications of rail transit development. When planning for new metro lines, governments and relevant agencies need to fully consider the impact of new rail transit development on the socio-economic structure of the corridor. It is crucial to ensure the mobility and activity space of low-income groups, allowing diverse income groups benefit from the new transit infrastructure and facilitating their encounters and interactions.

References

Deng, Y. & Zhao, P. (2022) The impact of new metro on travel behavior: Panel analysis using mobile phone data. Transportation Research Part A: Policy and Practice, 162, 46-57.
Florida, R. (2017) The new urban crisis: How our cities are increasing inequality, deepening segregation, and failing the middle class-and what we can do about it. Hachette UK.
Heilmann, K. (2018) Transit access and neighborhood segregation. Evidence from the Dallas light rail system. Regional Science and Urban Economics, 73, 237-250.
Lees, L., Slater, T. & Wyly, E. (2013) Gentrification. Routledge.
Loo, B. P., Fan, Z. & Moro, E. (2024) Residential and experienced social segregation: the roles of different transport modes, metro extensions, and longitudinal changes in Hong Kong. Humanities and Social Sciences Communications, 11(1), 1-13.
Moro, E., Calacci, D., Dong, X. & Pentland, A. (2021) Mobility patterns are associated with experienced income segregation in large US cities. Nature communications, 12(1), 4633.
Wang, D., Li, F. & Chai, Y. (2012) Activity spaces and sociospatial segregation in Beijing. Urban Geography, 33(2), 256-277.
Wong, D. W. & Shaw, S.-L. (2011) Measuring segregation: An activity space approach. Journal of geographical systems, 13, 127-145.