Low-density Cities Research Articles

The walkable environment: a systematic review through the lens of Space Syntax as an integrated approach

PurposeThis study reviews research applying Space Syntax, in conjunction with other methodologies, to explore walkability and socio-spatial relations in urban environments, with a particular emphasis on moderate- and low-density city centers.Design/methodology/approachA systematic literature review was conducted following PRISMA guidelines, reviewing English-language studies published from 2013 to 2023, involving introduction to research context, information sources and search strategy, screening process and application of eligibility and inclusion criteria to ensure a comprehensive evaluation of relevant papers.FindingsThis research highlights that the predominant focus in the literature has been on high-density city centers in existing Space Syntax studies, revealing a significant gap in understanding socio-spatial dynamics, particularly in moderate- and low-density city centers. Furthermore, this research found that technology-based tools were the most frequently used in past studies, with 454 instances, compared to participatory tools (191 instances) and observational tools (57 instances), when using Space Syntax as an integrated approach to explore socio-spatial relations in urban environments. Moreover, emerging technology-based tools remain the least used technological tools in the literature. Combining these approaches represents a recent trend that could offer valuable insights into pedestrian socio-spatial experiences in both broader urban contexts and smaller-scale city centers.Originality/valueUnlike previous literature reviews on Space Syntax that neglected its use as an integrated approach, this study uniquely explores the correlation between spatial configurations and human experiences through a review of studies that combine space syntax with other methods, including observational, participatory and technology-based tools to pinpoint the gaps. The research recommends further exploration of pedestrians’ socio-spatial needs by integrating Space Syntax with trends and less-explored technology-based tools.

Impact of vegetation coverage and configuration on urban temperatures: a comparative study of 31 provincial capital cities in China

Urban vegetation plays a crucial role in regulating temperatures and heat waves in urban areas. However, the influence of vegetation coverage and its configuration on surface temperatures in different climate zones at a national scale is unclear. To address this, we utilized high-resolution data to detect spatial patterns for 31 provincial capital cities in China. We integrated day and night surface temperatures to determine the influence of vegetative coverage and configuration on urban temperatures across different climate zones and city sizes. Our study revealed that a subtropical monsoon climate and medium-sized cities had the highest vegetative coverage and shape complexity. The best connectivity and agglomeration of vegetation were found in a temperate monsoon climate and large cities. In contrast, small cities, especially those under a temperate continental climate, had low vegetation coverage, high fragmentation, and weak agglomeration and connectivity. In addition, vegetative coverage had a negative impact on daytime surface temperatures, especially in large cities in a subtropical monsoon climate. However, an increase in vegetation coverage could result in warming at night in small cities in temperate continental climates. Although urban vegetation configuration also contributed to moderating surface temperatures, especially at night, they did not surpass the influence of vegetation coverage. The effect on nighttime temperatures of the configuration of vegetation increased by 3–6% relative to that of daytime temperatures, especially in large cities in a temperate monsoon climate. The contribution vegetation coverage and configuration interaction to cooling efficiency decreased at night, especially in medium-sized cities in a temperate continental climate by 3–5%. In addition, this study identified several moderating effects of natural and social factors on the relationship between urban vegetation coverage and surface temperatures. High duration of sunshine, low humidity and high wind speed significantly enhanced the negative impact of vegetation coverage on surface temperatures. In addition, the moderating effect of vegetation coverage was more pronounced in low population density cities and high gross domestic product. This study enhances understanding of the ecological functions of urban vegetation and provides a valuable scientific basis and strategic recommendations for optimizing urban vegetation and improving urban environmental quality.

The impact of urban configuration types on urban heat islands, air pollution, CO2 emissions, and mortality in Europe: a data science approach

The world is becoming increasingly urbanised. As cities around the world continue to grow, it is important for urban planners and policy makers to understand how different urban configuration patterns affect the environment and human health. However, previous studies have provided mixed findings. We aimed to identify European urban configuration types, on the basis of the local climate zones categories and street design variables from Open Street Map, and evaluate their association with motorised traffic flows, surface urban heat island (SUHI) intensities, tropospheric NO2, CO2 per person emissions, and age-standardised mortality. We considered 946 European cities from 31 countries for the analysis defined in the 2018 Urban Audit database, of which 919 European cities were analysed. Data were collected at a 250 m × 250 m grid cell resolution. We divided all cities into five concentric rings based on the Burgess concentric urban planning model and calculated the mean values of all variables for each ring. First, to identify distinct urban configuration types, we applied the Uniform Manifold Approximation and Projection for Dimension Reduction method, followed by the k-means clustering algorithm. Next, statistical differences in exposures (including SUHI) and mortality between the resulting urban configuration types were evaluated using a Kruskal-Wallis test followed by a post-hoc Dunn's test. We identified four distinct urban configuration types characterising European cities: compact high density (n=246), open low-rise medium density (n=245), open low-rise low density (n=261), and green low density (n=167). Compact high density cities were a small size, had high population densities, and a low availability of natural areas. In contrast, green low density cities were a large size, had low population densities, and a high availability of natural areas and cycleways. The open low-rise medium and low density cities were a small to medium size with medium to low population densities and low to moderate availability of green areas. Motorised traffic flows and NO2 exposure were significantly higher in compact high density and open low-rise medium density cities when compared with green low density and open low-rise low density cities. Additionally, green low density cities had a significantly lower SUHI effect compared with all other urban configuration types. Per person CO2 emissions were significantly lower in compact high density cities compared with green low density cities. Lastly, green low density cities had significantly lower mortality rates when compared with all other urban configuration types. Our findings indicate that, although the compact city model is more sustainable, European compact cities still face challenges related to poor environmental quality and health. Our results have notable implications for urban and transport planning policies in Europe and contribute to the ongoing discussion on which city models can bring the greatest benefits for the environment, climate, and health. Spanish Ministry of Science and Innovation, State Research Agency, Generalitat de Catalunya, Centro de Investigación Biomédica en red Epidemiología y Salud Pública, and Urban Burden of Disease Estimation for Policy Making as a Horizon Europe project.

Subsidizing residents or companies? An equilibrium-based analysis of subsidy strategies for EV charging facilities

This study examines the charging location choice behavior of residents in relation to employer-provided charging facilities and investigates the impact of different government subsidy strategies for charging facility construction on urban spatial structure and traffic-related air pollution. Using a monocentric two-zone city model, we analyze the residential distribution and travel mode choice of urban residents under various subsidy strategies from the perspective of social planners. The government can optimize urban resource allocation through transport infrastructure investments and implementation of emission taxes to maximize the so-called residents’ utility. We observe that despite the distorting effect of employer-provided charging facilities on travel mode choice, residents still experience an enhanced utility due to the positive environmental impact resulting from reduced pollution levels associated with electric vehicles (EVs) compared to gasoline vehicles (GVs). We provide numerical evidence to show that government subsidies, whether directed towards companies or residents, can effectively enhance the adoption of EVs and improve utility. In low-density cities, it is advisable for the government to encourage and subsidize residents in building charging facilities. Conversely, in high-density cities, prioritizing subsidies for companies would be more beneficial in improving utility and expanding the coverage of charging facilities. Furthermore, in cities where resident environmental awareness is relatively low, it is recommended that the government increase subsidies to promote EV adoption.

How does local context matter? Assessing the heterogeneous impact of electric vehicle incentive policies in China

This study reassesses the effectiveness of electric vehicle (EV) incentive policies in China and explores potential disparities in policy impact across different local contexts. Initially, employing panel data analysis, it evaluates policy effectiveness using data from 80 Chinese pilot cities spanning 2010 to 2022. Subsequently, cities are stratified based on varying income levels, traffic conditions, population density, and administrative hierarchy to facilitate an in-depth examination of the heterogeneous impacts of EV policies. Additionally, the Difference-in-Differences (DID) estimation method is employed to scrutinize the dynamic effects of these policies over time, enhancing the credibility of the panel model results. The findings reveal that purchase subsidies, parking benefits, driving privileges, and charging infrastructure have significant positive impacts on EV market share. Specifically, financial incentives are more effective in low-income, low-traffic, low-density cities, as well as in provincial capital cities while driving privileges are more suitable for high-income, high-traffic, and high-density areas. This study also finds that usage-phase policies increasingly drive EV adoption over time, offsetting the negative impact of subsidy reductions. The results of this study hold substantial implications for policymakers, providing insights to design context-based EV policies tailored to specific local conditions.

Quantifying the Impact of Urban Growth on Urban Surface Heat Islands in the Bangkok Metropolitan Region, Thailand

The urban built environment, comprising structures, roads, and various facilities, plays a key role in the formation of urban heat islands, which inflict considerable damage upon human society. This phenomenon is particularly pronounced in urban areas characterized by the rapid growth and concentration of populations, a global trend, notably exemplified in megacities such as Bangkok, Thailand. The global trend of urbanization has witnessed unprecedented growth in recent decades, with cities transforming into megametropolises that profoundly impact changes in urban temperature, specifically the urban heat island (UHI) phenomenon induced by the rapid growth of urban areas. Elevated urban concentrations lead to increased city density, contributing to higher temperatures within the urban environment compared to the surrounding areas. The evolving land-use surface has assumed heightened significance due to urban development, necessitating accelerated efforts to mitigate urban heat islands. This study aims to quantify the influence of urban growth on urban surface temperature in Bangkok and its surrounding areas. The inverse relationship between urban temperature and land surface temperature (LST), coupled with urban area density, was examined using Landsat 5 and 8 satellite imagery. The analysis revealed a positive correlation between higher temperatures and levels of urban growth. Areas characterized by high-rise structures and economic activities experienced the most pronounced impact of the heat island phenomenon. The city exhibited a notable correlation between high density and high temperatures (high–high), signifying that increased density contributes to elevated temperatures due to heat dissipation (significant correlation of R2 = 0.8582). Conversely, low-temperature, low-density cities (low–low) with a dispersed layout demonstrated effective cooling of the surrounding area, resulting in a significant correlation with lower local temperatures (R2 = 0.7404). These findings provide valuable insights to assist governments and related agencies in expediting planning and policy development aimed at reducing heat in urban areas and steering sustainable urban development.

Analysis of spatiotemporal transit accessibility and transit inequity of essential services in low-density cities, a case study of Nashville, TN

Evaluating the accessibility and equity of transit services to essential services that fulfill people’s fundamental needs is critical, especially in lower-density areas with limited transit services. Although numerous studies have analyzed the inequity of transit accessibility in dense, urban areas with robust transit networks, few of them evaluated transit inequity across multiple essential service categories (e.g., food stores, healthcare facilities, schools, etc.). This paper fills this research gap by focusing on a low-density, automobile-oriented city (Nashville, TN) to evaluate spatial transit inequities across essential service deserts and sociodemographic groups. The results of the case study show that many areas with higher transit-dependent demand (i.e., populations with limited personal vehicles, those living in poverty, and minority populations) tend to experience more restricted transit access to food, healthcare, school, and childcare facilities; interestingly, this is not the case for transit access to green space (specifically, parks). This study further identified essential service deserts by Local Indicator of Spatial Association (LISA) clustering and analyzed the correlation among them. The correlation results suggest that food deserts, healthcare deserts, school deserts, and childcare deserts are highly correlated with each other, while they have a lower correlation with park deserts. The findings of spatial transit inequity and the identification of essential service deserts provide crucial policy implications that can be used by transit agencies and local planning departments to prioritize their resources and target interventions to improve transit equity. This study contributes to the existing literature by proposing a systematic process that utilizes publicly available datasets to measure spatiotemporal transit supply, identify essential service deserts, and explore the correlation among these areas in a low-density city.

How does heterogeneity in dwelling type preferences relate to housing and built environment characteristics?

ABSTRACT Understanding housing preferences is critical for successful compact city development. However, there is limited research on understanding preference heterogeneity in dwelling type choices. Using the Household Income and Labour Dynamics in Australia survey, this paper identifies the key housing and built environment characteristics associated with changes in dwelling type choice from detached houses to high-density. A latent class choice model captures the heterogeneity of dwelling type preferences within a traditionally low-density city, Brisbane, Australia. Findings reveal six household classes with distinct dwelling preferences: Class 1 (senior households without children with other family members) and Class 2 (couple families with children) in inner-city areas, Class 3 (high-income young households) and Class 4 (low-income households without children) in middle-city areas, Class 5 (low-income families with children) and Class 6 (middle-income young families without children) in outer-city areas. Residential environments with better access to educational facilities encourage Classes 3 and 6 to change to high-density living. Greater land use diversity encourages Classes 2, 3, and 6 to move towards high-density living. The findings can be used to design and improve high-density housing for targeted population groups across inner-, middle- and outer-city areas.

Application of Digital Technologies in Controlling Urban Sprawl

Urban sprawl has been defined as an excessive conversion of rural land into urban land or excessive increase of the city beyond the optimal city size. Urban sprawl became a hot topic first in the United States, where the low-density city the problem emerged in the late 70s and early 80s. In Europe, urban sprawl wasn’t an issue until very recently, predominantly due to the structure of the European cities, which are traditionally more concentrated and densely populated, in contrast to the US cities. However, today we observe signs of urban sprawl in European cities, such as excessive decentralization, road congestion, lack of open space, overpopulation, etc. Recently urban city planners started using contemporary digital technologies to measure and control urban sprawl. This study discusses modern digital technologies used in present-day city planning.

Lawn with a side salad: Rainwater harvesting for self-sufficiency through urban agriculture

In a rapidly urbanising world, urban agriculture has garnered much attention for increasing resilience to a range of interrelated stressors, including climate change, food insecurity, economic instability and most recently, public health crises. Critical to understanding the viability of urban agriculture and ensuring its environmental sustainability, is the intersection of available land and the supply of agricultural inputs. Here, we address existing knowledge gaps related to urban agriculture and rainwater harvesting, by quantifying the self-sufficiency potential of half a million homes in Adelaide, South Australia. We developed a model that combines high resolution spectral and LiDAR imagery with productivity and irrigation data that reflect the actual behaviors of urban growers. Results indicate that 65% of residential properties contain enough available land to provide dietary self-sufficiency of vegetables, while capturing and storing adequate rainwater for irrigation, even in the modelled Dry year scenario. The modelled edible garden and associated storage tank would occupy around half of the lawn space in a typical residential block. These results highlight the substantial contribution urban agriculture can make to a more sustainable food systems in a low-density city.

The purchase intention of electric vehicles in Hong Kong, a high-density Asian context, and main differences from a Nordic context

In this paper, we aim to examine people's EV purchase intention in Hong Kong, an Asian compact city, and how the influential factors are different from the Western context, for which a low-density Nordic context, Denmark, was chosen. To achieve this, we conducted a survey in Hong Kong to understand the effects of several key factors, including subjective norms, personal norms, and perceptions and knowledge about EVs. Structural equation modelling was employed and multi-group analysis was conducted. Our findings show that EV purchase intentions in Hong Kong are highly value-driven with the assimilation to social expectations directly and strongly encouraging individuals' EV acceptance, which is different from the European case where the adoption desire is built upon the assessment of usage difficulty. In addition, range anxiety poses a direct deterrence to EV adoption even in the compact city. Availability of charging opportunities, be it the public ones or home-based ones, plays a critical role in an individual's decision of EV adoption in the high-density city. Our study reveals a strong disparity in the pathways towards EV adoption between the Asian and the Nordic contexts, thereby illustrating the necessity to differentiate e-mobility promotion policies in compact cities from low-density cities.

Parent-perceived neighbourhood environment, parenting practices and preschool-aged children physical activity and screen time: a cross-sectional study of two culturally and geographically diverse cities

BackgroundPreschool-aged children’s physical activity (PA) and screen time (ST) are important health-related behaviours likely influenced by PA opportunities, parental perceptions of neighbourhood safety and parenting practices pertaining to PA and ST. How these factors interact to impact on young children’s PA and ST, and whether their effects are generalisable across cultures and geographical location is not known. This study addressed these knowledge gaps by conducting pooled analyses of comparable data from two culturally and geographically diverse samples – Chinese parent-child dyads from an ultra-dense city (Hong Kong, China) and Latino parent-child dyads from a low-density city (Houston, USA).MethodsThe analytical sample consisted of 164 Hong Kong Chinese and 84 US Latino parent-child dyads with data on socio-demographic characteristics, parent-perceived neighbourhood destinations and facilities for children’s PA, physical and social safety-related neighbourhood attributes, PA-related parenting practices and child’s ST and accelerometer-assessed PA. Generalised linear models with robust standard errors accounting for neighbourhood-level clustering were used to estimate associations and interaction effects.ResultsHong Kong Chinese children accumulated less PA than US Latino children, although the latter had more ST. Hong Kong Chinese parents reported more parenting practices promoting inactivity. Neighbourhood PA opportunities were positively related to children’s PA only if parental perceptions of neighbourhood safety were favourable, and the associations of physical neighbourhood environment characteristics with children’s PA and ST depended on PA-related parenting practices. Community cohesion was positively related to children’s PA and negatively related to ST, while parental promotion of ST was positively associated with children’s ST. Correlates of children’s PA and ST did not differ by city.ConclusionsThe substantial differences in activity patterns between Hong Kong Chinese and US Latino preschool-aged children observed in this study are likely due to a combination of cultural and built environmental factors. However, the fact that no between-city differences in correlates of PA and ST were detected indicates that both populations of children are equally affected by parent-perceived neighbourhood environmental characteristics and parenting practices. Overall, this study highlights the importance of considering how various individual-, home- and neighbourhood physical and social factors interact to influence young children’s health-promoting activity levels.

Spatializing the roughness length of heterogeneous urban underlying surfaces to improve the WRF simulation-part 1: A review of morphological methods and model evaluation

Roughness length (Z0) is a critical parameter in atmospheric modeling that affects the land–atmosphere interactions. However, atmospheric models often use a fixed and relatively lower value for Z0 in urban areas, which cannot faithfully represent the actual heterogeneous urban underlying surfaces and reproduce the meteorological conditions. In this study, we provided a review of eight semiempirical models based on morphological methods from the literature and adopted them to develop a dataset of nonuniformly distributed roughness lengths in urban areas of Guangzhou, a highly urbanized city in China. In addition, we employed these datasets in the WRF model and evaluated the model. Overall, the estimated Z0 values in dense high-rise areas of the city were significantly higher than those in other regions. Different semiempirical models were found to generate significantly different Z0 values. The average local Z0 values of most models (7 out of 8) were higher than the model default value (0.5 m). Substituting the model default Z0 values with the localized non-uniform Z0 map revealed that the improvement in the simulated temperature and relative humidity at 2 m height was relatively small, whereas the improvement was significant for the simulated wind speed at 10 m height (WS10). The WRF simulations using the C71, T93, and K13 (see the main text for their definitions) schemes to estimate Z0 demonstrated the best improvements in the WS10 simulation of 54%, 50%, and 39%, respectively, compared with that using the default value. This improvement is of great value because many atmospheric models overpredict WS10. The simulation improved not only for the urban sites but also for the non-urban sites, demonstrating an improved ability for all stations. Among the schemes, the C71 and T93 semiempirical models were only applicable for low-density cities, whereas the K13 model applied to cities with significant urbanization. This study revealed the benefit of spatializing the heterogeneous urban roughness length to improve the meteorological simulations. This modification can be employed in the air quality model and further improve the simulations and forecasts of pollutant concentrations.

Mobility-as-a-Service: Simulation of Multi-Modal Operations in Low-Density Cities

In the case of the low-density city, empirical evidence continuously demonstrates that transit investment is not a magic bullet. Desirable outcomes are not guaranteed and are often dependent on development density and other urban characteristics. Mobility-as-a-service (MaaS) presents a new approach: a digital platform providing access to multi-modal travel alternatives and totally comprehensive integrated trip-making, planning, and payment services. Review of the literature highlights shortcomings in traditional transportation planning by examining aspects of multi-modal planning such as adoption, parterships, operations, integration, capacity implications, and impact analyses. To enhance the practice of multi-modal planning, the following experiment evaluates various performance measures and inter-modal interactions on International Drive in Orlando, Florida, U.S., via D- and I-optimal experimental designs in a simulated MaaS network. Alternative scenarios are developed comparing varied modal shares across five travel modes: personal vehicles, transit, ridesourcing (or ride-hailing), micro-mobility, and walking. The modal effects are analyzed to highlight the strengths and weakness of each mode under a variety of congestion conditions. While transit enjoys the lowest impact per person, ridesourcing demonstrates adverse effects across all measures. Based on the novel interactions of transit and ridesourcing with directional demand, strategies are outlined for optimizing ridesourcing-transit integration to reduce route travel time, queuing, and overall network delay. The performance impacts of curbside facilities are also discussed for improved multi-modal integration at the street level. These findings are applied to propose a framework for effective planning and implementation of mobility services in low-density cities, focused on operations, city-level connectivity, and curbside management.

Population Density or Populations Size. Which Factor Determines Urban Traffic Congestion?

A large number of articles have documented that as population density of cities increases, car use declines and public transit use rises. These articles had a significant impact of promoting high-density compact urban development to mitigate traffic congestion. Another approach followed by other researchers used the urban scaling model to indicate that traffic congestion increases as population size of cities increases, thus generating a possible contradictory result. Therefore, this study examines the role of both density and population size on traffic congestion in 164 global cities by the use of Stochastic Impacts by Regression on Population, Affluence and Technology model. We divide 164 cities into the two subgroups of 66 low density cities and 98 high density cities for analysis. The findings from the subgroups analysis indicated a clear-cut difference on the critical role of density in low-density cities and the exclusive role of population size in high-density cities. Furthermore, using threshold regression model, 164 cities are divided into the two regions of large and small population cities to determine population scale advantage of traffic congestion. Our findings highlight the importance of including analysis of subgroups based on density and/or population size in future studies of traffic congestion.

Self-sufficiency through urban agriculture: Nice idea or plausible reality?

With more than half of the world’s population residing in cities, there has been intense interest in urban agriculture’s contribution to sustainability and self-sufficiency. This paper provides new insights into the potential for food production to occur within residential properties. High-resolution optical imagery was employed to quantify residential land immediately available for vegetable production (i.e. residential lawn) in a low-density city. Adelaide (Australia) was used as a case study. Productivity was estimated according to three empirical (low, medium and high) and one commercial yield scenario. Under high and medium yield scenarios, lawn in a typical block exceeded the space required to achieve household self-sufficiency of vegetables. Under the high-yield scenario, 23 % of lawn area would be required to meet the recommended vegetable intake of residents, while under the medium yield scenario, 72 % would be required. This study demonstrates the plausible reality of self-sufficiency through backyard vegetable production. Other resources that might limit production, such as labour, water and nutrients, are explored in the discussion. Urban agriculture is shown to be particularly worthwhile in low density cities; contrasting previous research performed under different urban conditions. However, in this case study, potentially productive land has decreased over time.

Do City Size and Population Density Influence Regional Innovation Output Evidence from China?

This paper proposed a substantial gap to a large‐scale population density and city size on regional innovation output. To measure the impact of population density and city size on regional innovation output, this study employs the threshold effect model with panel data of 230 prefectures and cities from 2007 to 2016. Based on the econometric analysis, the results exhibit a positive and significant relationship between population density, city size, and innovation output. This correlation suggests that when one factor increases, the other increases in the parallel direction and vice versa. Moreover, when the city size expands the threshold value of 2.934 percent, the innovation promotes and increases the effects of urban‐scale expansion. On the other hand, for medium‐ and low‐density cities, the increase of urban population density has a significant and positive impact on urban innovation output. However, for high‐density cities, the increase of population density has no significant impact on innovation output.

Mono- and polycentric urban spatial structure and PM2.5 concentrations: Regarding the dependence on population density

City planners are increasingly drawn to the possibilities of transforming urban spatial structure as an important strategy for reducing air pollution. This paper addresses mixed findings in the existing literature through reliable methodology and heterogeneity tests. We examined the effects of spatial mono- and polycentricity on PM2.5 concentrations using spatial econometric models based on a three-year panel of data for cities at, or above, the prefecture in China. We found that population density had a robust moderating effect. That is, all else being equal, PM2.5 concentrations are lower when low-density cities have a strong-monocentric spatial structure and when high-density cities are polycentric. We estimated the population density threshold at which point the relationship between structure and density changes at about 160 persons/km.2 Our findings can serve as a possible criterion for differentiating low- and high-density cities in China and guide policymakers in planning optimal urban structures to mitigate air pollution.

From childless tower to child-full density: families and the evolution of vancouverism

ABSTRACT Vancouverism – amenity-rich neighbourhoods comprised of thin residential towers set on street-defining podiums – has been globally promoted as a new model of urbanism: high-density yet livable, even for families with children. Boosters claim profitable sustainability on a human scale; critics decry a sanitized elite vertical suburb. Lost in these debates is the little-known history of how this foundationally low-density city – where the single-family detached home dominated both the landscape and policy – became an international symbol of livable density. This history starts with a single confined mid-rise apartment zone in the 1920s designed to protect the majority detached-home city. In the 1950s policy promoted towers for childless professionals to bolster the tax base. Negative public reaction to the towers led to the election of an anti-density, yet anti-highway city council in the 1970s. Ironically, a cancelled highway spurred the council to build moderately-dense equitable family housing near downtown. After residents reported a desire for higher densities, Vancouverism was born.

Recent Literature about Urban Sprawl: A Renewed Relevance of the Phenomenon from the Perspective of Environmental Sustainability

The urban sprawl phenomenon has attracted the attention of social researchers since the mid-20th century. It seemed that all relevant aspects had been extensively studied and that it would be difficult to produce new studies with significant contributions. However, in the last decade, we have witnessed a revival of the literature on urban sprawl for three main reasons: (i) the existence of new methodologies to measure the phenomenon based on digital cartography and geo-referenced information, (ii) new hypotheses about the relevance of the formation of metropolitan areas not institutionally integrated into urban sprawl in many places and, mainly, (iii) the role of urban density in the environmental sustainability of cities. The recent literature on this third aspect has grown the most and around which it seems that new and interesting lines of future research will develop. The objective of this work is to present a synthetic review of the most recent literature on urban sprawl as of the end of the second decade of the XXI century. This review can serve to recapitulate the growing consensus that is being formed on the lower environmental sustainability of low-density cities and diffuse limits.