Neighborhood and socioeconomic change in emerging megapolitan nodes: tracking shifting social geographies in three rapidly growing United States metropolitan areas, 1980–2010

This paper investigates the complex demographic and social changes that have occurred in the neighborhoods of fast-growing United States metropolitan areas emerging as nodes in megapolitan regions between 1980 and 2010. A neighborhood typology is created using k-means cluster analysis to examine the demographic and housing characteristics, and geographic distribution, of neighborhoods that have existed in rapidly growing metropolitan areas. A socioeconomic index is created using principal component analysis (PCA) to analyze socioeconomic conditions within neighborhoods. Using data from the metropolitan areas of Las Vegas, Nevada; Austin, Texas; and Raleigh, North Carolina, this study identifies five neighborhood types, each of which has distinctive geographic and socioeconomic trends. The geographic orientation of each metropolitan area within their larger megapolitan region appears to have a role in the geography of neighborhood change. The results are also discussed in relation to human ecology, immigration, and economic restructuring.     

The suburbanization of poverty? An alternative perspective

A popular and powerful narrative focuses on a crisis of suburban decline in the United States. However, a consensus regarding the scope and scale of one dimension of suburban decline—poverty—is hindered by the use of contradictory definitions of suburban space. This research presents an alternative approach to measuring suburban poverty that is less computationally intensive yet capable of capturing complex shifts in the spatial distribution of poverty within metropolitan areas. An analysis of the distribution of poverty in the largest 100 metropolitan areas between 1990 and 2007–11 concludes that while poverty is increasing in the low-density suburbs of a handful of large metropolitan areas, the more general trend in most other metropolitan areas is an increase in poverty in moderately dense residential areas. Implicated in these trends are long-term trends in metropolitan area economic growth, a secular decline in inner-ring suburbs, and the impact of gentrification on housing opportunities for at-risk populations in large cities.     

轨道站点周边建成环境对残疾人出行行为的影响研究——以武汉市189个轨道站点为例

残疾人流动性是衡量社会公平发展的重要方面。由于特殊的身体和社会经济状况,残疾人出行行为具有更为独特的特征,也更易受建成环境影响。论文基于武汉市轨道交通智能刷卡数据,整合多源空间大数据,探索武汉市残疾人轨道交通出行时空特征,并利用地理加权回归(GWR)模型进一步探究轨道交通站点周边建成环境对轨道交通残疾人客流量影响的空间异质性。研究发现：① 地铁出行的残疾人中有29.7%具有通勤出行的特征,出行频率工作日高于休息日,且均呈现早晚错峰出行的趋势;② 15~30 min即大约5~10 km的中短距离出行最多,活动范围集中于三环线以内的主城区,且以同区出行活动最为频繁,跨江出行较少;③ 在大部分的研究范围内,公交站点密度、路网密度、大型公园密度和站点开通时间对站点残疾人客流量均具有正向影响;④ 换乘站的日均残疾人客流量明显高于非换乘站;⑤ 与以往研究结论不同的是,土地利用混合度、站点无障碍设施对站点残疾人客流量的影响并不显著。研究可为“残疾人友好型”的轨道交通站点建成环境优化和新站点土地利用布局提供数据支撑,增强城市公共服务人本化。     

Five decades of neighborhood classifications and their transitions: A comparison of four US cities, 1970–2010

This paper examines 50-year spatio-temporal trajectories of neighborhoods (Census Tracts) for four cities discerned by their population growth trends and spatial patterns of growth: Buffalo, New York; Charlotte, North Carolina; Chicago, Illinois; and Portland, Oregon. Using five decades of Census data from 1970 to 2010, a clustering procedure is used to establish five classes of neighborhoods: Suburban, Stability, Blue Collar, Struggling, and New Starts. The transitions and sequences of neighborhoods through these groups are compared, revealing marked differences in the dynamics of neighborhoods according by city. Findings show that while Struggling neighborhoods, characterized largely by high poverty and unemployment levels, were very unlikely to transition out of this group over the course of 50 years in the cities of Buffalo, Charlotte, and Chicago, nearly half Portland's struggling neighborhoods transitioned to a neighborhood of higher socioeconomic status during that time period. The types of neighborhoods that exhibited signs of gentrification also varied according to city. The variability of neighborhood trajectories was greatest for the rapidly growing cities of Charlotte and Portland while neighborhoods in Buffalo and Chicago tended to follow a more predicable downgrading process.     

Mexican and Central American immigrant communities in the boom and bust housing markets of the 2000s

Classic immigrant enclaves, largely voluntary and temporary, have historically served as a strong platform for integration in United States metropolitan areas. However, trends in the early 2000s, including new destinations and skyrocketing housing costs, may have reshaped the landscape, particularly for numerically dominant immigrant groups with very low socioeconomic status. In this article, I use data for 56 metropolitan areas and 31,563 census tracts from the 2000 Census and the 2005–2009 American Community Survey to examine the relationship between the change in concentration of Mexican and Central American immigrants and the characteristics of neighborhoods in 2000. The analyses suggest that, across metropolitan areas, these immigrant communities consolidated in neighborhoods with low home values, adequate but overcrowded housing, relatively small shares of their own immigrant group, and large shares of other Hispanics. Demographic dynamics may have weakened immigrant support networks, leaving Mexican and Central American immigrants vulnerable, particularly in a subset of metropolitan areas where this population grew most substantially outside the central cities.     

中国大都市多中心空间演化过程的非均衡动态模拟

构建了一个基于垄断竞争、规模经济、空间成本、消费者多样化偏好以及商品和服务差异化的大都市多中心空间结构模型,并整合基于agent的建模,借助非均衡(out-of-equilibrium)动态模拟,探讨了人口规模和消费需求、区域间和区域内商业产品及服务的替代弹性、固定成本投入、区位和交通条件等因素的"持续"变化对的大都市空间结构演化的影响过程。模拟表明:以商业为代表的经济活动往往集聚在具有区位优势、规模经济和消费能力的大都市传统中心,而交通条件的持续改善、新兴郊区次中心与传统城市中心之间以及城区内部商业产品和服务的不断差异化对大都市的多中心空间结构有重要影响,但影响的程度不同。更重要的是,大都市的人口规模和消费能力对新兴郊区次中心的形成作用显著。     

广州市家庭收入与住房特征对应关系的区位差异性

以广州市中心区(天河区)和郊区(南沙区)为研究案例,依托2010年中国(广东)家庭动态跟踪调查数据,基于家庭户住房的邻里特征、建筑特征、区位特征、家庭收入等13个指标构建路径分析模型,研究广州市居民家庭收入与住房特征的映射关系和影响方向。在此基础上,采用多群组路径分析方法研究区位因素对“收入→住房特征”的影响程度及其差异性。最后利用方差方程和均值方程,分析不同区位条件下(中心区和郊区)的住房特征差异。结果表明：① 家庭收入更显著地决定住房特征,对邻里特征的影响并不显著;② 区位对“收入→住房邻里特征”的关系具有显著调节作用,而对“收入→住房建筑特征”的调节作用较弱;③ 在中心城区和郊区的内部,家庭收入更显著地影响住房建筑特征,而对邻里特征基本无显著影响;④ 郊区家庭收入对公共交通时间便利性、住房面积、厕所设施水平、拥有住房数量、住房综合条件等几个主要住房特征指标的影响程度大于中心城区;⑤ 中心城区住房的邻里特征明显优于郊区,但建筑特征明显差于郊区。显示出广州市住房邻里特征与建筑特征在不同区位条件下的“互换特征”。     

西安市贫困空间结构特征与发生机理

以中国西部综合型大城市、老工业基地西安市为例,基于大规模调研数据,采用相对贫困概念和FGT指数研究城市内部微观单元贫困特征的空间分异与形成机理。结果表明,西安市整体的贫困状况较为缓和,贫困覆盖面广,但深度和强度较弱;随着城市圈层扩展,贫困属性呈现出“U”型演化曲线,表现出“高贫困、破碎、混杂—低贫困或非贫困、弱连续、较弱混杂—较低贫困、连续、内部分化、相对均一—较高贫困、相对连续、较强混杂”的演化规律,成熟建成区和新兴扩展区内侧分化区的贫困状况最弱;城市内部已基本发育成熟了旧城衰退型、发展剥夺型、传统工业衰退型、“城中村”型和新增长中心邻近型等5种表征不同贫困主体及户籍、住房等特征的贫困极核。西安城市贫困空间的结构特征是其社会经济发展的阶段性和区域性的集中体现,是在城市宏观社会经济和整体地域结构背景下,各收入阶层在生活成本、就业机会、公共资源、政策导向和社会心理亚文化圈等因素的作用下,通过接替、过滤、自主集聚、排斥隔离和强化等机制重塑城市社会空间的综合表现。     

THE CHANGING METROPOLITAN STRUCTURE OF ATLANTA,GEORGIA: LOCATIONS OF FUNCTIONS AND REGIONAL STRUCTURE IN A MULTINUCLEATED URBAN AREA

The study of suburban downtowns in the past has emphasized the emergence of multinucleation in urban structure and the growing independence of multiple urban realms. The purpose of this study is to develop a framework to identify and compare the employment profiles of each downtown in a metropolitan area, including the CBD. Using data on retail employment, services, and finance, insurance, and real estate (FIRE), the four downtowns that exist in the Atlanta region are examined, together with scattered-site employment. This study suggests that downtowns, rather than existing as independent urban realms, are mutually interdependent based on work-trip commuting patterns, shopping behavior, and traffic flows in general, all of which increasingly are automobile based. Mass transit ridership suffers from its primary focus on radial services to and from the CBD and poor service levels to other downtowns and to scattered employment sites.     

The Urban Settlement Patterns of Disadvantaged Migrants

Abstract

Disadvantaged migrants to metropolitan areas are segregated by race, ethnicity, or socioeconomic status within the residential areas of central city poverty neighborhoods. Whereas black migrants are generally restricted to ghetto space, regional cultural similarities and feedback in the social communication network are important to the residential location of lower class whites. The urban settlement patterns of a sample of recent disadvantaged white migrants to Indianapolis, Indiana, vary from the clusters of migrants from Appalachia and the South to the more dispersed pattern of migrants from Indiana, Illinois, and Ohio, and other metropolitan areas. The residential location of migrants from Appalachia and the South is geographically restricted by cultural constraints, and heavy reliance upon a limited network of friends and relatives in the housing search. However, the sociocultural resources of the Midwest group and the previous urban experience of metropolitan migrants increase the range of housing opportunities in Indianapolis that are available and known to them.     

National capital region of India: a case of metropolitan growth management

The author examines the process of urbanization in Delhi, India's National Capital Region. An urban plan for the metropolitan area that emphasizes decentralization is assessed, and the spatial distribution of the population is described. The central city, suburban areas, and transportation and communication systems that link them are also considered.     

城市轨道交通对土地利用变化的时空效应

定量分析轨道交通对城市内部精细土地利用复杂变化影响的时空效应,对于预测未来新建站点对土地利用的影响以及规划方案的调整与优化具有重要的指导意义。本文提出结合历史高分遥感影像与POI数据获取多时间节点精细土地利用信息的方法,并以广州市二号和八号地铁线为例,结合逐步回归模型与站点用地功能分类,从时间和空间两个维度定量研究地铁对土地利用转变的复杂影响过程与空间差异规律。结果表明,轨道交通促使站点周边低密度居住用地向商业用地、高密度居住用地等高效益土地利用方式的转变;轨道交通在规划、建设、运营不同阶段对于周边土地利用的影响呈现显著的差异规律;地铁站点对土地利用变化影响规律具有明显的空间异质性特征,与站点在城市里的位置以及站点周边的土地利用有关,对城市中心区域的影响较小,对郊区的影响主要与可用的非建设用地面积相关,而工业用地对土地利用变化具有限制作用;轨道交通还带来用地功能和性质的转变,这样的转变大多发生在地铁站点开通运营的时间点。     

GEOGRAPHIC CONTEXT AND CONCENTRATED URBAN POVERTY WITHIN THE UNITED STATES

Responding to previous analyses that assume that places are passive recipients of the various macro-level social phenomena associated with concentrated urban poverty, I hypothesize that concentrated urban poverty takes on different forms in different places as a result of how macro-level social phenomena are mediated by locally specific structures. To investigate how concentrated urban poverty takes on different forms in different places, I first decompose the poverty rates of all high-poverty urban neighborhoods in the United States into their race-specific rate and composition effects, and classify high-poverty neighborhoods based on these decomposition values. The results of the analysis demonstrate that poverty in a majority of the high-poverty neighborhoods in the United States is undoubtedly affected by geographically specific processes. For example, within one set of high-poverty neighborhoods, poverty is associated with both the lack of economic opportunity and high rates of class-based residential segregation within mixed-race immigrant ethnic/immigrant enclaves in large gateway cities. A second set of high-poverty neighborhoods, located in the metropolitan areas of the southern United States, has high rates of poverty because of the residential segregation and geographic concentration of poverty-prone African Americans. And lastly, among a third set of tracts, poverty experiences in African American ghettos are linked to declining economic and social opportunities and class-based residential segregation within large manufacturing cities. A set of recommendations for additional research includes addressing how one-size-fits-all anti-poverty public policies should be modified for the specific needs of each type of high-poverty neighborhood. [Key words: context, poverty, segregation, employment, race, ethnicity.]     

北京公交就业可达性及其地区和人群差异

运用经济普查、人口普查数据和基于百度地图的公交出行时间数据,分析北京都市区基于公共交通的就业可达性及其在城市不同人群和地区间的差异。结果表明：北京都市区的居民可在60分钟内通过公共交通到达18.3%的都市区工作岗位,这比美国100个最大的都市区的平均就业可达性水平要高,接近于美国纽约都市区的就业可达性水平。同时,由于就业郊区化程度有限和以中心—放射式布局的公交网络,北京都市区内的公交就业可达性存在着巨大的区域差异,中心城区的就业可达性远远高于郊区。此外,人口居住的郊区化程度远远高于就业的郊区化程度,导致北京都市区宏观层面的职住不平衡。随着人口居住郊区化程度的提高,公共交通如何服务居住日益分散的人口,提高就业可达性,是一项巨大的挑战。研究还发现,由于城市中心区的大部分就业为高技术的就业岗位,因此高受教育程度人口能更多地享受目前公共交通系统的便利,而受教育程度低的人口和外来人口公交就业可达性较低。为解决弱势群体所面临的就业可达性的不平等问题,需要更多的规划与政策干预。     

THE IMPACT OF FEDERAL LOCAL PUBLIC TRANSPORTATION ASSISTANCE UPON TRAVEL BEHAVIOR

Despite substantial amounts of federal assistance to local public transportation, ridership has declined considerably in the country as a whole since 1964, suggesting an ineffective government program. A city-by-city comparison of assistance received with changes in transit ridership shows that declines in transit usage were least in cities receiving the most federal aid, and greatest in cities receiving the least aid. This demonstrates that federal aid has had an impact upon travel behavior. Indeed, it is the single most important factor explaining differences between cities in travel behavior changes in the 1970's.     

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

The temporal dimensions of public transit accessibility have recently garnered an increasing amount of interest. However, the existing literature on transit accessibility is heavily based on oversimplified assumptions that transit services operate at deterministic speeds using predetermined timetables. These measurements may overestimate transit accessibility, especially for large metropolitan areas where inter- and intra-modal transfers are frequent. To handle travel time uncertainty, a multi-modal transit accessibility modeling approach is proposed to account for realistic variations in travel time and service reliability. The proposed approach is applied to the mapping of transit accessibility in Shenzhen (China), where transit services exhibit significant travel time variations over space and time. Compared to traditional transit accessibility measures, our method has been demonstrated to better capture intrinsic spatial and temporal accessibility variations with complex multi-modal transit networks. Normal distribution of inter-stop travel times and constant travel speed between GPS sampling points are assumed to simply the computation, which we consider to adjust in future studies to better quantify the dynamics of transit accessibility across space and time.     

THE IMPACT OF FEDERAL LOCAL PUBLIC TRANSPORTATION ASSISTANCE UPON TRAVEL BEHAVIOR

Despite substantial amounts of federal assistance to local public transportation, ridership has declined considerably in the country as a whole since 1964, suggesting an ineffective government program. A city-by-city comparison of assistance received with changes in transit ridership shows that declines in transit usage were least in cities receiving the most federal aid, and greatest in cities receiving the least aid. This demonstrates that federal aid has had an impact upon travel behavior. Indeed, it is the single most important factor explaining differences between cities in travel behavior changes in the 1970's.     

Declining inner suburbs? A longitudinal-spatial analysis of large metropolitan regions in Canada

Spatially referenced quantitative research that attempts systematically to assess inner suburban decline in Canadian metropolitan areas is almost completely missing from the literature. This paper aims to fill this gap and examine whether inner suburban decline is occurring in Canada. Aggregated census tract level data are used to assess all zones for decline based on relative prosperity changes in median household income, average dwelling values, and average gross rent. The results indicate that inner suburbs in Canadian cities experienced a decline in median household income, average dwelling value, and prosperity factors between 1986 and 2006. While a few possible explanations and policy approaches are offered, more research is necessary to explore the implications of these trends.     

THE IMPACT OF CHANGES IN PRICING POLICY UPON TRANSIT RIDERS OF VARYING AGES IN CHICAGO *

The elderly and young represent a significant segment of the transit-dependent ridership in metropolitan areas. The impacts of a change in pricing structure and transfer policy upon these groups are examined using survey data generated from riders of the Regional Transportation Authority in Chicago before and after a major restructing of fares and transfer policy. Results indicate that the elderly and young differ from the general population of respondents in their sensitivity to these changes. Moreover, it appears that the restructuring of fares did not adversely affect ridership patterns for these subgroups of transit users.     

BEYOND THE STREET CORNER: THE HIDDEN DIVERSITY OF HIGH-POVERTY NEIGHBORHOODS

The widely reported social pathologies of urban ghettos, barrios, and other slum areas have played a prominent role in the backlash against Aid to Families with Dependent Children and other social programs. The policy debate, however, has been fueled by a series of stereotypes about the characteristics of the residents of such neighborhoods. This article complements existing ethnographic research on high-poverty neighborhoods by examining social and economic data from the 1990 Census on all neighborhoods in U.S. metropolitan areas. High-poverty areas are found to contain a surprising amount of social and economic diversity. Although some residents clearly engage in “underclass” lifestyles, many of their neighbors are not public-assistance recipients and do participate in the labor market, albeit in lower-skill occupations and for fewer hours and lower wages. Other similarities and differences between high-poverty areas and other neighborhoods are explored, leading to a richer understanding of the nature of concentrated urban poverty.