The 15-Minute City Quantified Using Mobility Data

Americans travel 7 to 9 miles on average for shopping and recreational activities, which is far longer than the 15-minute (walking) city advocated by ecologically-oriented urban planners. This paper provides a comprehensive analysis of local trip behavior in US cities using GPS data on individual trips from 40 million mobile devices. We define local usage as the share of trips made within 15-minutes walking distance from home, and find that the median US city resident makes only 12% of their daily trips within such a short distance. We find that differences in access to local services can explain eighty percent of the variation in 15-minute usage across metropolitan areas and 74 percent of the variation in usage within metropolitan areas. Differences in historic zoning permissiveness within New York suggest a causal link between access and usage, and that less restrictive zoning rules, such as permitting more mixed-use development, would lead to shorter travel times. Finally, we document a strong correlation between local usage and experienced segregation for poorer, but not richer, urbanites, which suggests that 15-minute cities may also exacerbate the social isolation of marginalized communities

Urban Visual Intelligence: Studying Cities with AI and Street-level Imagery

The visual dimension of cities has been a fundamental subject in urban studies, since the pioneering work of scholars such as Sitte, Lynch, Arnheim, and Jacobs. Several decades later, big data and artificial intelligence (AI) are revolutionizing how people move, sense, and interact with cities. This paper reviews the literature on the appearance and function of cities to illustrate how visual information has been used to understand them. A conceptual framework, Urban Visual Intelligence, is introduced to systematically elaborate on how new image data sources and AI techniques are reshaping the way researchers perceive and measure cities, enabling the study of the physical environment and its interactions with socioeconomic environments at various scales. The paper argues that these new approaches enable researchers to revisit the classic urban theories and themes, and potentially help cities create environments that are more in line with human behaviors and aspirations in the digital age

Building Sustainable and Inclusive Cities: Analyzing the Impact of Planning Paradigms in the US

The three papers in this dissertation study how different urban planning paradigms—normative ideas used by planners to shape the built environment—can support more sustainable development patterns. To investigate this topic, I analyze large-scale, high-resolution data using various analytical methods. The first paper examines the sustainability implications of the 15-minute city model, which emphasizes local living. Using large-scale GPS data from US cities, the study examines the relationship between trip length, access to nearby amenities, and segregation. The results suggest that less restrictive zoning rules could make it easier for people to access nearby amenities without traveling long distances. However, such policies also run the risk of increasing the social isolation of the poor. In the second paper, I investigate the consequences of developing suburban neighborhoods using the garden city model, a historical paradigm emphasizing urban form as a key driver of neighborhood well-functioning. I develop and validate a methodology to measure the key attributes of the garden city model at scale and over time by inferring it from neighborhood layouts. Combining neighborhood design measurements with data on individual mobility and emissions, I demonstrate that residents of neighborhoods designed using the garden city model are more sedentary, more socially isolated, and produce more greenhouse gas emissions due to longer commutes induced by the street network. Finally, the third paper tests the idea that neighborhood form persists over time in the context of the United States Housing Corporation, the first housing initiative funded by the federal government in 1918. Comparing neighborhoods that were planned but canceled with others that were planned and constructed, the study shows that street shape and block configuration persist via path dependence, while other urban design features like the composition of blocks do not. Overall, these papers highlight the critical link between physical form and sustainability in urban planning.Ph.D

Role of urban form in immigrant assimilation

Thesis: M.C.P., Massachusetts Institute of Technology, Department of Urban Studies and Planning, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages ).In this thesis I investigate the relationship between the built environment and the residential segregation of immigrants at the building level. I use micro-data that includes the exact address of all the foreign and native population in Barcelona, combined with geometric indicators for urban shape at the block level. Using these data, I construct measures of segregation over time to evaluate the degree to which individuals from different origins, share building space with other immigrants or with the native-born Spaniards. Differences in the built environment appear to have a sizable effect on how immigrants coexist with host communities. The arrival of immigrants to suburban areas is associated with less segregation than other areas. In particular, certain spatial qualities such as open space centrality, coverage and compactness are beneficial in mediating the effect of immigrants on segregation. My results reinforce the idea that a process of suburbanization might have decreased segregation between immigrants and natives, possibly due to native communities being less sensitive to coexisting with immigrant populations in less dense areas.by Arianna Salazar Miranda.M.C.P

Understanding Urban Economies, Land Use, and Social Dynamics in the City: Big Data and Measurement

Recent advancements in data collection have expanded the tools and information available for urban and spatial-based research. This paper presents an overview of spatial big data sources used in urban science and urban economics, with the goal of directing and enriching future research by other applied economists. We structure our discussion around data origins and analytical methods, discussing geographic information maps, GPS and CDR, textual repositories, social media, credit card transactions, street imagery, sensor readings, volumetric data, street patterns, transportation metrics, public records, geocoded historical data, business analytics, real estate transactions, and crowdsourced input. While aiming to provide an overarching perspective, we also touch upon common challenges in urban big data research, especially those unique to data collection, analysis, and inference

Cities and infectious diseases: Assessing the exposure of pedestrians to virus transmission along city streets

As cities resume life in public space, they face the difficult task of retaining outdoor activity while decreasing exposure to airborne viruses, such as the novel coronavirus. Even though the transmission risk is higher in indoor spaces, recent evidence suggests that physical contact outdoors also contributes to an increased virus exposure. Given that streets constitute the largest percentage of public space in cities, there is an increasing need to prioritise their use to minimise transmission risk. However, city officials currently lack the assessment tools to achieve this. This article evaluates the extent to which street segments are associated with spatiotemporal variations of potential exposures of pedestrians to virus transmission. We develop a multi-component risk score that considers both urban form and human activity along streets over time, including (a) an assessment of pedestrian infrastructure according to the average width of pavements, (b) a measure of accessibility for each street based on its position in the street network, (c) an activity exposure score that identifies places along streets where exposure could be higher and (d) an estimate of the number of pedestrians that will pass through each street during weekdays and weekends. We use Amsterdam in the Netherlands as a case study to illustrate how our score could be used to assess the exposure of pedestrians to virus transmission along streets. Our approach can be replicated in other cities facing a similar challenge of bringing life back to the streets while minimising transmission risks.Internet of ThingsHuman-Centred Artificial Intelligenc

Ser e parecer: indumentária e hierarquia social na sátira de frei Lucas de Santa Catarina, Portugal, século XVIII

A partir da perspectiva analítica da cultura material investigaremos a valorização das aparências na sociedade portuguesa da primeira metade do século XVIII, examinando representações do vestir e do aparentar na literatura de cordel produzida por frei Lucas de Santa Catarina. Trata-se de observar alguns aspectos das relações entre aparências e comportamentos na construção de uma sátira que visava criticar a falta de correspondência entre ser e parecer, num contexto em que a mobilidade social despontava em diversos setores. Tais textos fornecem ao historiador um amplo quadro no qual indumentária e comportamentos são descritos de maneira imbricada nas rotinas cotidianas. A partir dessas descrições, observaremos os conjuntos de artefatos necessários ao cuidado da imagem a ser apresentada no meio social, analisando seus usos e a percepção deles transcritos nas fontes selecionadas. Assim, refletiremos sobre alguns dos embates acerca das vestimentas e das modas, que se fundamentavam na contestação da ascensão social e no esforço de conter um amplo processo de mudança que marcava a sociedade portuguesa do período.From the analytical perspective of material culture, this article will investigate the valuation of appearances in Portuguese society in the first half of the 18th century, through the examination of representations of clothing and appearance in the cordel literature produced by Frei Lucas de Santa Catarina. The objective is to observe some aspects of the relationships between appearances and behaviors in the construction of a satire that aimed to criticize the non-correspondence between being and appearing, in a context of emerging social mobility for several sectors. Such texts provide historians with a broad framework where clothing and behavior are described amid everyday routines. From these descriptions, we will observe the sets of artifacts necessary to care for the image to be presented in social environments, analyzing its uses and the perception of these transcripts in the selected sources. Thus, we will reflect on some of the clashes over clothing and fashion trends that were based on the challenge of social ascension and the effort to contain a broad process of change that marked the Portuguese society of the period

Rare predicted loss-of-function variants of type I IFN immunity genes are associated with life-threatening COVID-19

BackgroundWe previously reported that impaired type I IFN activity, due to inborn errors of TLR3- and TLR7-dependent type I interferon (IFN) immunity or to autoantibodies against type I IFN, account for 15-20% of cases of life-threatening COVID-19 in unvaccinated patients. Therefore, the determinants of life-threatening COVID-19 remain to be identified in similar to 80% of cases.MethodsWe report here a genome-wide rare variant burden association analysis in 3269 unvaccinated patients with life-threatening COVID-19, and 1373 unvaccinated SARS-CoV-2-infected individuals without pneumonia. Among the 928 patients tested for autoantibodies against type I IFN, a quarter (234) were positive and were excluded.ResultsNo gene reached genome-wide significance. Under a recessive model, the most significant gene with at-risk variants was TLR7, with an OR of 27.68 (95%CI 1.5-528.7, P=1.1x10(-4)) for biochemically loss-of-function (bLOF) variants. We replicated the enrichment in rare predicted LOF (pLOF) variants at 13 influenza susceptibility loci involved in TLR3-dependent type I IFN immunity (OR=3.70[95%CI 1.3-8.2], P=2.1x10(-4)). This enrichment was further strengthened by (1) adding the recently reported TYK2 and TLR7 COVID-19 loci, particularly under a recessive model (OR=19.65[95%CI 2.1-2635.4], P=3.4x10(-3)), and (2) considering as pLOF branchpoint variants with potentially strong impacts on splicing among the 15 loci (OR=4.40[9%CI 2.3-8.4], P=7.7x10(-8)). Finally, the patients with pLOF/bLOF variants at these 15 loci were significantly younger (mean age [SD]=43.3 [20.3] years) than the other patients (56.0 [17.3] years; P=1.68x10(-5)).ConclusionsRare variants of TLR3- and TLR7-dependent type I IFN immunity genes can underlie life-threatening COVID-19, particularly with recessive inheritance, in patients under 60 years old

Correction: Rare predicted loss-of-function variants of type I IFN immunity genes are associated with life-threatening COVID-19

International audienc