Polycentric Urban Development Research Articles

Polycentricity and TOD-ness synergy: A novel composite index for integrated development of employment centers and residential cores in transit-oriented neighborhoods

Proximity of transit-oriented development (TOD) goals to polycentric urban development in the field of controlling negative effects of urban sprawl reinforces polycentricity and TOD-ness spatial synergy. Furthermore, identification of transit-oriented neighborhoods that have high potential to become secondary employment centers (ECs) is one of the most important challenges facing urban transport planners and land use policy makers. This research explained integrated development of ECs and residential cores (RCs) in transit-oriented neighborhoods using a novel composite index. The index is designed based on TOD-ness and polycentricity measures using spatial statistical methods and helps urban planners and policy makers to better identify polycentric TODs as transit-oriented residential neighborhoods with high potential to become secondary employment centers. Research findings confirmed higher accessibility of polycentric TODs to public services and public and private transportation that have better integration in the development of urban facilities and transportation systems. Furthermore, the findings confirmed polycentricity and TOD-ness spatial synergies in polycentric TODs.

TOD Development in Shenzhen Rail Transit Based on SWOT Model

In today's urban planning field, Transit-Oriented Development (TOD) has become a crucial research topic. With the acceleration of urbanization and increasing population density, traffic problems have become key factors affecting urban development and living quality of residents. Therefore, discussing how to effectively plan urban traffic and realize the harmonious coexistence between traffic and city has become the focus of urban planning scholars and practitioners. However, there is still a lack of unified understanding regarding the role of railway TOD planning in urban development. Therefore, this paper takes Shenzhen as an example and adopts a SWOT analysis to examine the TOD development mode of Shenzhen's railways, based on the city's structure, railway layout, and development strategy. This paper finds that the polycentric urban development pattern of Shenzhen is closely connected to its railway planning. The foundation for Shenzhen's railway TOD construction is relatively solid, and the prospects for development are optimistic. However, many issues in the future development space and planning design still need to be addressed.

Polycentric urban development with state-led administrative division adjustment: A policy insight for urban spatial transformation

Polycentric urban development with state-led administrative division adjustment: A policy insight for urban spatial transformation

Can polycentric urban development simultaneously achieve both economic growth and regional equity? A multi-scale analysis of German regions

Polycentric urban regions have been advocated for, and justified as enhancing both economic growth and overall competitiveness while also creating more equitable and balanced metropolitan regions. We examine the role of regional polycentricity in effectuating certain desirable outcomes, specifically enhancing economic productivity and minimizing spatial disparities simultaneously in German urban regions ( Großstadtregionen) as a case study. Using econometric analysis of both functional and morphological polycentricity measures, our results indicate that polycentric development can effectively reduce regional disparities in urban regions, but not simultaneously promote economic productivity. These findings confirm previous studies that progress toward one goal hampers progress toward another. Further investigation at a finer scale suggests that the borrowed size effect is essentially a “win-loss” game between peripheries and urban core(s) within the same urban region. Peripheries benefit from the spillovers generated by nearby urban core(s), thereby narrowing regional economic gaps and leading to more equitable regions. However, the gains of the peripheries are canceled out by the losses of the urban cores, and polycentric development has an insignificant overall effect on regional economic productivity.

Measuring polycentric urban development with multi-temporal Sentinel-1 SAR imagery: A case study in Shanghai, China

Studies on polycentric urban development (PUD) have been done by using LandScan and point of interest data. So far, the quality of PUD products has been limited by the spatio-temporal resolution of these datasets. Using Sentinel-1 SAR missions with a 10 m pixel spacing and a weekly repeat cycle, this study, for the first time, explores the potential of using a time series of Sentinel-1 SAR images for measuring urban polycentricity. In particular, we develop a variance-based filtering method to mitigate speckle noise. We propose the Kittler and Illingworth with a Modified Model (KI-MM) method to accurately identify PUD-related changes. We focus on the mean distance of new-born patches and the mean patch area for a PUD-related change analysis. These allow us to associate SAR tailor-made output with PUDs. The proposed methods were implemented on Google Earth Engine platform using 304 Sentinel-1 SAR images on the city of Shanghai, China, acquired between 2015 and 2018. We have tested 80 distribution models and found that the Laplace distribution is the best model for the KI-MM method. Our results show 2526, 2409, 4232 new-born patches for 2015–2016, 2016–2017, 2017-2018, with areas equal to 18, 20, 36 km2, respectively. Using cross-validation with Sentinel-2 (optical) reference, we found that the matching rates and F1-score between detected changes and reference for the years 2015–2016, 2016–2017, 2017-2018 were equal to 89.79% and 91.67%, 100% and 100%, 88.64% and 94.06%, respectively. We conclude that Sentinel-1 SAR images are suited to PUD applications at an intra-city scale with a high spatio-temporal resolution.

To What Extent Can Satellite Cities and New Towns Serve as a Steering Instrument for Polycentric Urban Expansion during Massive Population Growth?—A Comparative Analysis of Tokyo and Shanghai

In response to the call of the New Urban Agenda—Habitat III for a reinvigoration of long-term and integrated planning towards sustainable urban development, this paper presents an empirical comparative study of planning practices based on the “satellite city” and “new town” concepts in Tokyo and Shanghai to examine from a long-term perspective how well they have guided polycentric urban development at a time of massive population growth. We aim to deliver evidence-based contributions to boost the knowledge transfer between the Global North and the Global South. The paper adopts a multi-dimensional framework for the comparative analysis, including a review of long-term urban development policies and an inspection of the population distribution and extent of built-up areas using time-specific categorizations to map the spatiotemporal changes based on GHSL data. The comparative analysis shows that urban plans in Tokyo and Shanghai based on satellite cities and new towns as steering instruments for polycentric urban growth management have not lived up to the original aspirations. In fact, the intended steering of population distribution has essentially failed, despite the practical steps undertaken.

Location matters: High-speed railway (HSR) stations in city evolution

This study examines the nexus between high-speed rail (HSR) stations and city evolution from an urban science perspective. We analyzed 1627 HSR stations built from 1976 to 2021 in 533 Chinese and European cities. Node or activity clusters in cities are identified through the street network. Then, the urban forms of Chinese and European cities are compared and the Zipf's law is tested. We found that activity clusters in Europe tend to be more contiguous and clustered, suggesting a clear downtown. In Chinese cities, these clusters are more scattered, suggesting polycentric urban development. When the Zipf's law is applied to the size distribution of activity clusters, the rank-size rule is supported both at the aggregate and country levels. Generally, it takes roughly two decades for an HSR station to be able to mature in attracting related development, such as residence and businesses, to complete the exploration process of city evolution. Finally, contributory factors for the integration of HSR stations with the urban fabrics are examined. Apart from the size of the city, economic power, station features and the spatial pattern of activity clusters, the relative location of the HSR station in relation to the urban form matters. Our study contributes both to the HSR and urban science literature, and has practical implications for locational decisions about HSR stations.

Unravelling the association between polycentric urban development and landscape sustainability in urbanizing island cities

Polycentric urban development has become popular worldwide as expected to generate greater agglomeration externality and facilitate socioeconomic achievements. Despite much insightful work on urban polycentricity in coastal agglomerations or megacities, few studies have focused on how polycentric urban development affects landscape sustainability in vulnerable island cities. This paper characterized the urban polycentricity from the perspective of morphological and functional dimensions during 1990–2020 in Yuhuan island city, China, and quantified the association between polycentric urban variables and island landscape changes by spatial regression. The results showed that there was a mismatch in development between the morphological and functional polycentricity, in which the functional dimension was lagging. In response, island landscape patterns became fragmented and scattered. With the application of GWR models, the effects of two polycentric factors on island landscape changes varied spatially and temporally. The stronger relationships between them were identified in regions where more heterogeneous patterns were presented, such as the subcenters and their surroundings and reclamation areas. These trends were mainly attributed to industrial suburbanization and the development of new economic zone and Damaiyu port. Our findings call for a more balanced functional urban polycentricity; and local-specific landscape effects should be scheduled in island planning practice and sustainable development.

Node-place model extended by system support: Evaluation and classification of metro station areas in Tianfu new area of Chengdu

The construction of new urban areas has become one of the important ways for urban regeneration throughout the process of polycentric urban development. New urban area construction following transit-oriented development (TOD) conception advocates development around the public transportation stations. To gain more benefits around the stations, it is necessary to conduct an ex-ante evaluation of TOD projects in the new urban area. The Node-place (NP) model is a commonly used method for TOD evaluation and classification, which essentially designs an analytical framework for assessing station areas in both transport (node) and land use (place) aspects. The objective of our study is twofold. First, based on the original NP model, we propose the node-place-system support (NPS) model by introducing a novel evaluation dimension—system support—which quantitatively describes the relationship between local stations and the overall urban system. Second, taking advantage of multi-sourced data and Geographical Information System (GIS) techniques, we employ the proposed NPS model to evaluate and classify the metro stations in the Tianfu New Area of Chengdu, China. The results show that most stations present a balanced relationship between transport and land use performances. However, for a fraction of these balanced stations, we observe a mismatch between the system support and NP performances. Accordingly, we identify the system-mismatched stations and provide targeted improvement strategies for urban design.

Integrating sustainability indicators and governance structures via clustering analysis and multicriteria decision making for an urban agriculture network

Environmental, social, and economic sustainability patterns interact in various dimensions of an urban environment. Exacerbated population growth triggers an emphasis on better resource management strategies addressing the balance of supply and demand over food, energy, and water sectors while considering social and economic development. Promoting sustainable development goals requires governance structures and functions within and across the food, energy, and water sectors, specifically due to polycentric urban development. This study emphasizes food security via an urban agriculture network in the greater Miami metropolitan area, encompassing the three counties of Palm-Beach, Broward, and Miami-Dade. Given the existing governance structure, we quantified several sustainability indices for clustering analysis to agglomerate urban agricultural sites (UASs) and to help identify the priority of clusters in terms of vulnerability or risk level according to their priority index in multicriteria decision-making. The cases of eight clusters were selected for the visualization of the UASs ranked by multicriteria decision-making based on scenarios prioritized for governance under the impacts of climate change, social equity, and economic development. The role of governance structure was highlighted for signifying the incentive programs to enhance the overall sustainability performance of UASs in an urban food–energy–water nexus.

Gender difference in commuting travel: A comparative study of suburban residents in Beijing and Shanghai

This paper aims to extend the current scope of gender inequality research to developing countries and to compare gendered commuting patterns in different spatial contexts. We focus on suburban residents in Beijing and Shanghai, which have comparable population and economic sizes, similar trends of residential suburbanization, but different urban structures. Based on data collected through activity diary surveys in 2017, We investigate gender differences in commuting distance and modes, and we find that the gender gap is manifested differently in the two cities. In both cities, women are less likely to commute by automobile but more reliant on public transport than men. But women’s lower transport mobility is compensated with shorter commuting distances in Shanghai, a city with polycentric employment structure, but not in Beijing with a monocentric urban structure. The policy implication is that polycentric urban development with efficient public transport services can allow job-housing proximity and reduce commuting burdens for suburban working women in Chinese cities.

Sociocultural problems of polycentric urban development in the context of urbanization

The article examines the cultural and philosophical and socio-philosophical significance of polycentric urban planning strategies in the framework of the historical process of urbanization. Network and polycentric urban planning began to develop in the 19th century, was associated with a new course for the conscious and planned development of cities and assumed an even distribution of public facilities and communications, the unification of urban space with connecting axes, the integration of transport and engineering infrastructure. These trends in urban planning were caused by interrelated technological, economic, social and political factors, such as scientific and technological progress, the industrial revolution, rapid urbanization. The purpose of the article is to determine the social and cultural significance of urban planning strategies implemented in some European capitals of the XIX century in the context of the general process of urbanization. The scientific novelty of the article is determined by the correlation of the topic under consideration with the problems of modern urban structures. The article is based on an interdisciplinary, complex and systematic theoretical approach. A theoretical analysis of urban planning strategies and urban space development was carried out in order to identify the most promising and progressive trends in urban planning that anticipated the modern principles of urban space formation. The conclusions of the article include the characterization of the influence of polycentric urban development on the formation of a psychosocial environment and typical characteristics of the spiritual life of citizens. A review of studies on socio-cultural and philosophical problems of urbanism helps to identify the impact of polycentric urban planning, including on modern society, residents of modern cities.

Can Changes in Urban Form Affect PM2.5 Concentration? A Comparative Analysis from 286 Prefecture-Level Cities in China

It is crucial to the sustainable development of cities that we understand how urban form affects the concentration of fine particulate matter (PM2.5) from a spatial–temporal perspective. This study explored the influence of urban form on PM2.5 concentration in 286 prefecture-level Chinese cities and compared them from national and regional perspectives. The analysis, which explored the influence of urban form on PM2.5 concentration, was based on two types of urban form indicators (socioeconomic urban index and urban landscape index). The results revealed that cities with high PM2.5 concentrations tended to be clustered. From the national perspective, urban built-up area (UA) and road density (RD) have a significant correlation with PM2.5 concentration for all cities. There was a significant negative correlation between the number of patches (NP) and the average concentration of PM2.5 in small and medium-sized cities. Moreover, urban fragmentation had a stronger impact on PM2.5 concentrations in small cities. From a sub-regional perspective, there was no significant correlation between urban form and PM2.5 concentration in the eastern and central regions. On the other hand, the influence of population density on PM2.5 concentration in northeastern China and northwestern China showed a significant positive correlation. In large- and medium-sized cities, the number of patches (NP), the largest patch index (LPI), and the contagion index (CONTAG) were also positively correlated with PM2.5 concentration, while the LPI in small cities was significantly negatively correlated with PM2.5 concentration. This shows that, for more developed areas, planning agencies should encourage moderately decentralized and polycentric urban development. For underdeveloped cities and shrinking cities, the development of a single center should be encouraged.

Influences of landform and urban form factors on urban heat island: Comparative case study between Chengdu and Chongqing

Although the degraded urban thermal environment has been widely concerned, whether monocentric or polycentric urban development can alleviate urban heat island (UHI) is still debatable, particularly considering different types of cities in plain and mountainous settings. To fill the gap, this study chose the cases of Chengdu on alluvial flatlands and Chongqing on mountainous landforms in China for comparison. Adapting to natural landforms, Chengdu has a dominated monocentric urban form, whereas Chongqing has a naturally polycentric urban form. This study found that areas with high UHI intensity were located in the urban center and peripheral suburbs in Chengdu, while those were located in the peripheral industrial zones in Chongqing. The spatial error model and random forest regression results showed that natural elements such as vegetation and water had similar influences and contributions to UHI. However, distinct landforms and urban forms played critical roles in UHI differences among the two cities. Impervious surface and building density were the dominant variables to UHI of Chengdu, while sky view factor and industrial zones were the main contributors to UHI of Chongqing. The findings called for corresponding policy strategies to optimize urban form and improve the urban thermal environment.

Regenerating Hong Kong’s New Towns: Resilience and Collaboration in the Context of Polycentric Urban Development

Hong Kong’s New Towns, since their emergence in the 1960s, have been planned with various strategies aimed at creating self-sufficient communities. External challenges have led to varied successes in achieving this goal, as Hong Kong’s industry, society, and modes of live and work have gradually changed. As the city continues to build new urban areas and connecting infrastructures, its existing New Towns deserve to be re-evaluated, as they can continue to grow and adapt in parallel with Hong Kong’s evolving economic and strategic position with the Greater Bay Area. This article presents a series of urban design strategies for the upgrading of existing New Towns, developed in the context of the Master of Science in Urban Design programme at The Chinese University of Hong Kong. Based on their historic development, current qualities and challenges, and a review of international precedents, theories and policies, four strategic methods for New Town regeneration are discussed. Firstly, we assess the strategic location of Kowloon’s New Territories to develop principal nodes within the polycentric structure of the region. Secondly, we explore strategies for increased economic and employment opportunities, through the promotion of regional innovation systems and entrepreneurialism. Thirdly, the role of public space and placemaking in the upgrading of neighbourhoods and community life is discussed. Finally, we review strategies to enhance the ecological performance of New Towns.

Mapping the Spatial Conditions of Polycentric Urban Development in Europe: An Open‐source Software Tool

Urban polycentricity has become a key concept in urban and regional studies and is increasingly adopted as an organizational framework for conducting empirical research. Within this literature, polycentric urban regions are commonly defined as territories that have multiple, proximately located (sub)centers and are characterized by balanced urban development. However, analytical‐operational frameworks to identify and classify PURs are often ad hoc efforts to answer a specific research question and underlying work is often shelved rather than shared and/or made accessible. As a result, challenges associated with generalizability, reproducibility, and replicability clearly loom large in the urban polycentricity literature. Against this backdrop, this article describes the discrepancy between a rich debate on polycentricity and the paucity of tools enabling the disambiguation and reproducibility of results claimed by various authors around this polysemic concept. We present an online and open tool—PURban—that brings together the major analytical‐operational frameworks and data sets in urban polycentricity research and allows parametrizing key operational choices. To illustrate the tool, we demonstrate how it facilitates the identification, mapping and analysis of degrees of morphological polycentricity in European urban systems. We conclude by reflecting on how this tool can act as a catalyst for future research on urban polycentricity.

Simulating the urban spatial structure with spatial interaction: A case study of urban polycentricity under different scenarios

Polycentric urban development is gaining momentum in both scholarly research and real-life practice. This brings new demand for planning support systems to simulate and analyse the urban spatial structure in terms of polycentricity under various urban policy scenarios. With the help of emerging urban data, urban simulation techniques, and network science, this study proposes a workflow to simulate the urban spatial structure with spatial interaction as a part of the planning support system. Using Singapore as a case study, this study has explored the resulting urban spatial structure with four employment distribution strategies. The results suggest that planning practices impact urban spatial structure and its spatial interaction by redistributing urban morphological elements, such as employment in this study. Also, our results show that the physical urban spatial structure and spatial interaction are closely related. These results reinforce the role of urban planning practice to achieve a more sustainable and coherent urban built environment. Through this empirical evidence, our workflow exemplifies the potential of the planning support system to help urban planners and governments understand their urban policy regarding urban polycentricity.

Assessing polycentric urban development in Shanghai, China, with detailed passive mobile phone data

Despite growing studies on the distinction between morphological and functional polycentricity, the present methods for identifying polycentricity often focus on the morphological dimension due to a lack of information about intra-urban functional flows, and are limited by the multifarious nature of people’s spatiotemporal interactions. This study proposes a new approach, examining the degree of polycentricity in Shanghai at the intra-urban level using passive mobile phone data. A series of polycentricity indicators are used and are benchmarked against previous studies. Notably, we found that people’s daily movements within a subcenter indicate that morphological polycentricity is also at play in Shanghai. We conclude that morphological and functional polycentricity may coexist at the intra-urban level, and that a mobile phone data approach can offer an alternative method to elucidate both the morphological and functional features of subcenters.

Analyzing polycentric urban development in China: Evidence from intercity knowledge collaboration

Analyzing polycentric urban development in China: Evidence from intercity knowledge collaboration

The historical aspects of polycentric urban development on the example of Barcelona

The article concerns the problems of implementation of the modern urban planning methods and principles in the context of historical process of urbanization. Network and polycentric urban planning actively developed in 19th century and implied the equal distribution of public facilities and communications, the unification of the urban space with the connecting axes, the integration of transport and engineering infrastructure. The purpose of the article is to consider the urban planning strategies of Barcelona’s renovation of 19th centuries and to define it’s correspondence to the tasks of modern urban development. The relevance of the topic is determined by it’s connection with problems of modern growth-oriented urban structures. The article is based on complex and system theoretical approach. Theoretical analysis of urban planning strategies and urban space development is implemented to reveal the most perspective and progressive tendencies of urban planning, which anticipated the modern principles of urban space formation. The results of the work include the characteristic of polycentric Urban structures on the example of Barcelona, the determination of it’s key features. The review of researches, dedicated to the history of urban planning and the problems of modern urban planning allows to make the conclusions about the advantages of polycentric urban planing and it’s perspectives in future development of the cities.