Does metropolitan form affect transportation sustainability? Evidence from US metropolitan areas

In this paper, we examine transportation sustainability in American metropolitan areas using transportation-related CO2 emissions, public transit accessibility, and commuting times as indicators. Though variations in these indicators may stem from historic contexts, policies, institutional arrangements, social and cultural origins, the spatial structure of metropolitan areas—in particular their formal characteristics—may also be a contributing factor. To test this relationship, we identify metropolitan form metrics from prior literature that are expected to impact transportation outcomes, and choose five metrics to which we introduce significant improvements. We apply the metrics to all 166 Combined Statistical Areas in the US, using an open-source GIS toolbox released along with the paper. Our findings demonstrate that form-based metrics provide a better explanation to CO2 emissions, public transit accessibility, and commuting times in US metro areas than the simpler population size or density metrics typically used in practice. We also show that counter to prior literature on urban scaling laws and economies of scale, which have argued that larger cities and metro areas are more sustainable per capita, transport-related CO2 emissions and transit accessibility are actually less favorable in larger CSAs when controlling for formal characteristics of metropolitan areas. Instead of scale, compactness has the highest elasticity with respect to transportation sustainability of metro areas.

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Urban scaling in rapidly urbanising China

Urban Studies ◽

10.1177/00420980211017817 ◽

2021 ◽

pp. 004209802110178

Author(s):

Weiqian Lei ◽

Limin Jiao ◽

Gang Xu ◽

Zhengzi Zhou

Keyword(s):

Urban Population ◽

Economies Of Scale ◽

Scaling Laws ◽

Temporal Evolution ◽

Urban System ◽

Scaling Analysis ◽

Scaling Exponent ◽

Scaling Exponents ◽

Economic Output ◽

Urban Scaling

Understanding the scaling characteristics in China is critical for perceiving the development process of rapidly urbanising countries. This paper conducts a comprehensive scaling analysis with quantitative assessment of a large number of diverse urban indicators of 275 Chinese cities. Our findings confirm that urban scaling laws can also be applied to rapidly urbanising China but demonstrate some unique features echoing its distinct urbanisation. Chinese urban population agglomeration results in more effective economic production but the economies of scale for infrastructure are less obvious. Some urban indicators associated with infrastructure and living facilities surprisingly scale super-linearly with urban population size, contrary to expected sublinear scaling behaviours. In developing countries, different-sized cities have diverse agglomeration, industrial and resource allocation advantages, which can be reflected by scaling exponents. We characterise these unique features in detail, exploring the spatial disparities and temporal evolution of scaling exponents ( β). Strong regional variations and differences are particularly pronounced in Northeast China and the Beijing-Tianjin-Hebei Urban Agglomeration. Scaling exponent variations over time reflect the temporal evolution of the urban system and measure the coordination and balance of urbanisation. Economic output was most efficient in 2009 and β of GDP was slightly greater than 1.15 in recent years. Urban land expansion has been accelerating since 2000 with β remaining around 0.85–0.90. The study of urban scaling in China is enlightening in elaborating the uniqueness and coordination of urban development in rapidly urbanising countries and provides support in formulating differentiated urban planning for different-sized cities to promote coordinated development.

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Quantifying multi-modal public transit accessibility for large metropolitan areas: a time-dependent reliability modeling approach

International Journal of Geographical Information Science ◽

10.1080/13658816.2018.1459113 ◽

2018 ◽

Vol 32 (8) ◽

pp. 1649-1676 ◽

Cited By ~ 8

Author(s):

Tong Zhang ◽

Shaoxuan Dong ◽

Zhe Zeng ◽

Jing Li

Keyword(s):

Metropolitan Areas ◽

Public Transit ◽

Time Dependent ◽

Reliability Modeling ◽

Modeling Approach ◽

Transit Accessibility

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Public transit accessibility approach to understand the equity for public healthcare services: A case study of Greater Mumbai

Journal of Transport Geography ◽

10.1016/j.jtrangeo.2021.103123 ◽

2021 ◽

Vol 94 ◽

pp. 103123

Author(s):

Gajanand Sharma ◽

Gopal R. Patil

Keyword(s):

Public Transit ◽

Healthcare Services ◽

Public Healthcare ◽

Transit Accessibility

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Evidence for the homothetic scaling of urban forms

Environment and Planning B Urban Analytics and City Science ◽

10.1177/2399808318810532 ◽

2018 ◽

Vol 47 (5) ◽

pp. 870-888 ◽

Cited By ~ 6

Author(s):

Rémi Lemoy ◽

Geoffrey Caruso

Keyword(s):

Land Use ◽

Population Density ◽

Scaling Laws ◽

Radial Distance ◽

Three Dimensions ◽

City Size ◽

Cube Root ◽

Radial Profiles ◽

Population Grid ◽

Urban Scaling

The size and form of cities influence their social and environmental impacts. Whether cities have the same form irrespective of their size is still an open question. We analyse the profile of artificial land and population density, with respect to the distance to their main centre, for the 300 largest European cities. Our analysis combines the GMES/Copernicus Urban Atlas 2006 land use database at 5 m resolution for 300 larger urban zones with more than 100,000 inhabitants and the Geostat population grid at 1 km resolution. We find a remarkable constancy of radial profiles across city sizes. Artificial land profiles scale in the two horizontal dimensions with the square root of city population, while population density profiles scale in three dimensions with its cube root. In short, cities of different size are homothetic in terms of land use and population density, which challenges the idea that larger cities are more parsimonious in the use of land per capita. While earlier literature documented the scaling of average densities (total surface and population) with city size, we document the scaling of the whole radial distance profile with city size, thus liaising intra-urban radial analysis and systems of cities. Our findings also yield homogenous spatial definitions of cities, from which we can re-question urban scaling laws and Zipf’s law for cities.

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