Polycentrism,commuting, and residential location in the San Francisco Bay area

"The San Francisco Bay Area has taken on a distinct polycentric metropolitan form, with three tiers of hierarchical employment centers encircling downtown San Francisco.... In this paper it is found that polycentric development is associated with differentials in suburban and urban commute trip times: commute trips made by employees of suburban centers are shorter in duration than commute trips made by their counterparts in larger and denser urban centers. Differentials were even greater, however, with respect to commuting modal splits. Lower density, outlying employment centers averaged far higher rates of drive-alone automobile commuting and insignificant levels of transit commuting....The effects of housing availability and prices on the residential locational choices of those working both in urban and in suburban employment centers are also investigated...."     

Job-worker spatial dynamics in Beijing: Insights from Smart Card Data

As a megacity, Beijing has experienced traffic congestion, unaffordable housing issues and jobs-housing imbalance. Recent decades have seen policies and projects aiming at decentralizing urban structure and job-worker patterns, such as subway network expansion, the suburbanization of housing and firms. But it is unclear whether these changes produced a more balanced spatial configuration of jobs and workers. To answer this question, this paper evaluated the ratio of jobs to workers from Smart Card Data at the transit station level and offered a longitudinal study for regular transit commuters. The method identifies the most preferred station around each commuter's workpalce and home location from individual smart datasets according to their travel regularity, then the amounts of jobs and workers around each station are estimated. A year-to-year evolution of job to worker ratios at the station level is conducted. We classify general cases of steepening and flattening job-worker dynamics, and they can be used in the study of other cities. The paper finds that (1) only temporary balance appears around a few stations; (2) job-worker ratios tend to be steepening rather than flattening, influencing commute patterns; (3) the polycentric configuration of Beijing can be seen from the spatial pattern of job centers identified.     

大城市职住空间匹配及其与轨道交通的协调发展研究:以深圳市为例

轨道交通将高密度职住空间串联,主要是从客流生成的角度促进人们更多地使用轨道交通和减少小汽车的使用,还需要从客流流动的角度考虑职住空间匹配的需求以及其与轨道交通的协调关系.以深圳市作为研究案例,采用建筑普查数据、社保信息数据、居住人口数据和轨道交通刷卡数据等多源信息数据,通过分析深圳市的职住空间分布特征及其与轨道交通的关系,探讨职住空间匹配问题及其与城市轨道交通的互动协调.研究提出:发展轨道型职住匹配,关注低生活成本居住空间的供给,但不能以轨道型职住匹配替代近域型职住匹配;弱化轨道交通的长距离通勤功能,基于就业中心的集聚构建生活通勤圈,形成客流流动的多中心城市格局.     

中等城市就业与居住空间组织特征及拓展模式——以广东省清远市为例

研究表明,城市用地、交通环境、同城效应等宏观因素和住房市场、学区房、通勤成本等中观因素对以清远市为代表的中等城市的就业与居住空间组织具有较大的影响,可采用居住新城先导、产业园区带动、综合配套更新、对外交通导向和同城效应影响五种模式来推动我国中等城市的就业与居住空间拓展,以促进城市就业与居住空间的平衡发展.     

The spatial structure of American cities: The great majority of workplaces are no longer in CBDs,employment sub-centers,or live-work communities

Urban transport and land use policies are informed by our perceptions of the prevailing spatial structure of cities. This structure can be characterized by five models: The Maximum Disorder model, the Mosaic of Live-Work Communities model, the Monocentric City model, the Polycentric City model, and the Constrained Dispersal model, where the great majority of jobs are dispersed outside employment centers and where workers and workplaces in a metropolitan-wide labor market adjust their locations to be within a tolerable commute range of each other. We examine evidence from a stratified sample of 40 U.S. cities and from the 50 largest U.S. cities in 2000 to show that the latter model best characterizes the spatial structure of contemporary American cities. The Constrained Dispersal model is, in essence, a hybrid model that combines elements of all other models. We found that, on average, only 1 out of 12 people live and work in the same community; only 1 out of 9 jobs is still located in the CBD; and only 1 out of 7 jobs is located in employment sub-centers outside the CBD. All in all, the great majority of jobs—3 out of 4 of them—is dispersed outside employment centers, including the CBD, and is beyond walking or biking distance. Maintaining and increasing the productivity of American cities now require a sustained focus on meeting the travel demands of this great majority of commuters, rather than promoting transportation strategies focused on improving access to CBDs and employment sub-centers, or within live-work communities.     

Guidelines for a Polycentric Region to Reduce Vehicle Use and Increase Walking and Transit Use

Abstract

Problem, research strategy, and findings: The monocentric development pattern in the Alonso–Mills–Muth model underpinned theoretical discussions of urban form in the 1960s and 1970s and truly dominated theory up to the point when Joel Garreau published Edge City: Life on the New Frontier in the early 1990s. Monocentric development patterns remain dominant to this day among smaller metropolitan areas in the United States. However, for larger metropolitan areas in the United States, regional transportation plans suggest a paradigm shift to a polycentric structure. We review 126 regional transportation plans in the United States and find that a hierarchy of centers connected by high-quality transit has become the dominant vision for most of them. The plan for Salt Lake City (UT), for example, strives for a multicentered region even though secondary centers are only beginning to emerge beyond a dominant downtown. Generally missing from regional transportation plans are quantitative criteria for designating and guiding centers: In no case are the quantitative criteria empirically based on proven transportation benefits. Here we investigate how the built environment characteristics of centers are associated with people’s travel mode choices and vehicle use. We employ visual and exploratory approaches through a generalized additive model (GAM) to identify nonlinear relationships between travel outcomes and “D” variables (density, diversity, design, destination accessibility, and distance to transit) within centers. The model and plots help us recommend the built environment characteristics of centers.

Takeaway for practice: The built environment thresholds and relevant tools provided here can enable planners to make informed decisions about future growth patterns, set realistic—yet visionary—goals, and improve the overall health of its residents and communities. We provide strategies and tools that planning agencies, such as metropolitan planning organizations, transit agencies, and municipalities, can adopt to channel developments into centers.     

The Connection Between Public Transit and Employment

Urban transit systems in most American cities…have become a genuine civil rights issue-and a valid one-because the layout of rapid-transit systems determines the accessibility of jobs to the Black community. If transportation systems in American cities could be laid out so as to provide an opportunity for poor people to get meaningful employment, then they could begin to move into the mainstream of American life. A good example of this problem is my home city of Atlanta, where the rapid-transit system has been laid out for the convenience of the white upper-middle-class suburbanites who commute to their jobs downtown. The system has virtually no consideration for connecting the poor people with their jobs. There is only one possible explanation for this situation, and that is the racist blindness of city planners. Martin Luther King, Jr. (1986, pp. 325-326)

Much attention is being paid to the role of public transit in employment-related mobility for urban residents, yet there is very little evidence of the degree to which one affects the other. Little research has focused on how labor participation is affected by increases in urban workers' access to public transportation. Research on the spatial mismatch hypothesis has dealt with the relationship between labor participation and the spatial separation of workers' residences from suitable jobs; however, most analyses concentrate on commuting time or distance as a function of auto use. Few studies have considered the impacts of public transportation on labor participation. This article describes a study analyzing the locations and employment characteristics of workers with varying levels of access to public transit. Using census data and a variety of spatial measures generated by a geographic information system (GIS), a two-stage least squares regression was used to estimate the relationship of access to public transit with labor participation levels for Portland, Oregon, and Atlanta, Georgia. The results suggest that access to public transit is a significant factor in determining average rates of labor participation within these two cities.     

中国城市的郊区化与公交导向开发

中国大城市的郊区化使得许多居民被安置在比他们以前居住地可达性更差的地方,而需要采用机动化方式出行。基于对最近才迁居到上海郊区三个街区的居民所进行的当前出行及回顾以前出行的调查数据,研究了迁居至外围地区对就业可达性、通勤方式选择和通勤时耗的影响。发现:迁居后,居民的就业可达性下降很快,与此相伴随的是机动化出行比例及通勤时间的大幅度提高。然而,也发现:迁居到郊区地铁站附近的居民就业可达性下降的较少,而且对于许多居民来说,如此迁居正鼓励居民出行方式从非机动车方式转向公共交通方式。我们得出结论认为:对于把快速郊区化的中国城市引导走向更持续的道路,可寄予公交为导向的开发模式以很高的期望。     

Analyzing intra-metropolitan poverty differentiation: causes and consequences of poverty expansion to suburbs in the metropolitan Atlanta region

Although metropolitan areas have traditionally been viewed as dichotomous structures with a central city and surrounding suburbs, the development patterns of such areas have taken on a multi-ring sectoral and polycentric structure in the context of intra-metropolitan spatial differentiation. Using the longitudinal census database (1970–2000) for the Atlanta metropolitan region, this study showed not only substantial increases in poverty and its concentration in suburban areas such as inner- and middle-ring suburbs and some suburban employment centers, but also causal factors for changes in poverty by race and subarea. The results suggest that unemployment and rental housing burden were the strongest determinants of levels of poverty and its change across race and subareas, indicating the importance of jobs and affordable rental housing to alleviating poverty and its concentration.     

大城市住房建设中的空间失配及其成因解析——以上海市为例

试图从空间失配角度解读上海大都市区化进程中的住房问题,并提出政策建议。立足统计数据,采用空间偏离指数与空间断面分析法对住房建设展开研究,发现住房制度改革以来增量住房建设的空间偏离、公共服务设施的极化供给、轨道交通建设问题都导致了住房建设的空间失配。这在推高房价、导致低收入群体空间锁定的同时,也降低了“多中心”规划实践的空间绩效。结论是：过于单一的商品化供应、缺乏协调的住房行动、圈层蔓延的空间拓展都是住房空间失配的重要成因;意图解决大城市住房困境的政策干预需要破解住房建设中存在的空间失配困境;而这有赖于中观层面居住、就业等功能的空间藕合与微观层面“多层次”住房供应的有效结合。     

Spatial mismatch and the affordability of public transport for the poor in Singapore’s new towns

Singapore has redeveloped its Central Area into business districts and relocated the affected population to new towns. Unfortunately, this strong center policy has hindered the development of employment sub-centers. Most jobs are located in the Central Area, resulting in a spatial mismatch that the government is attempting to address by building a world-class public transport system. However, the poor not only face affordability problems and long travel times for employment, but they are also experiencing a shrinking supply of employment due to economic restructuring. Route tests were conducted, and the results indicate that the poor, who generally choose to travel by bus, have to spend up to 9.8% of their household income per month and 70 min per trip from their neighborhoods to the city center. Those who take the hub-and-spoke network have to spend 13.2% of household income and take 60 min for similar trips. To increase the job-seeking range of these people, they should be offered concessions to encourage use of the hub-and-spoke network. The government should also build a light-rail transit line to pass through the Central Catchment Nature Reserve to connect employment sub-centers.     

轨道交通系统对大都市区多中心空间结构的影响

多中心作为一项城市发展战略，已逐渐 受到国内外大都市区的广泛认可。基于集聚—分 散维度和单中心—多中心维度理论，结合百度热 力图等人口空间化数据，提出能够客观反映不同 大都市区多中心空间结构差异性的测度方法和 量化指标——多中心指数（PI）。建立轨道交通 系统对多中心指数的多元线性回归模型，以全国 40个已开通运营轨道交通的大都市区作为实证 研究对象，探索轨道交通系统对大都市区多中心 空间结构的影响效应。研究发现，在控制了道路 交通、人口就业和经济发展等因素的影响下，轨 道交通系统通过线网规模、线网结构以及站点 布局对大都市区的多中心空间结构产生显著影 响，但影响的正负取决于近远郊圈层的轨道交 通发展水平。通过科学规划和系统建设，提高 近远郊线网比重、次中心TOD耦合度以及轨道 网密度，可以显著提高我国大都市区多中心空间 结构的发展水平。     

城市低收入群体的就业可达性变化研究——以北京为例

职住平衡被新城市主义和精明增长的支持者所倡导,它不仅可以降低小汽车出行,促进城市就业,也关系到社会公平。本文选择北京作为案例,采取网络OD矩阵分析法,以平均通勤时间做测度指标,考察居住在可支付性住房中的低收入群体到商业就业中心的就业可达性。研究发现,采取公交方式付出的通勤时间大约为小汽车通勤方式的2倍,这反映了不同群体的就业可达性确实因交通方式的不同选择而存在差异。从时间变化上看,2004年之后比之前的可支付性住房,无论采取公交还是小汽车出行的平均通勤时间都更长,表明低收入群体在就业可达性上被置于更不利的境地,这将为中国城市未来的可支付性住房布局和交通规划提供借鉴,并进而对城市中弱势群体的居住、就业给予实实在在的关怀。     

Mobilizing social capital: Which informal and formal supports affect employment outcomes for HOPE VI residents?

Using a mixed-methods approach, this study examines the relationship between informal social support and formal support services and employment outcomes among residents of a public housing development relocated as part of a HOPE VI project in Charlotte, North Carolina. Informal social supports are resources accessible through family and friends within a neighborhood and formal support services are provided by case managers and service providers. We find that when former public housing residents are enrolled in case management longer and have high satisfaction with their case manager, this leads to better employment outcomes. In addition, having strong bonding ties among public housing neighbors has a negative influence on employment. This study sheds light on how case managers play a role in promoting economic mobility by mitigating social and economic crises and providing bridging capital for poor families.     

Housing location choices of the poor: does access to jobs matter?

Abstract

This research investigates whether access to jobs affects poor households’ residential location choices using data from individual households in the Chicago Metropolitan Area. Our results, based on discrete choice models, show that the effects of job accessibility on household location choices are contingent upon households’ automobile ownership and employment status. Places with higher job accessibility by public transit mode are more likely to attract poor households that do not own cars but have at least one employed worker or one labour force participant, while job accessibility by automobile travel mode has no positive effect on the location choices of poor households who own automobiles. The results stress the importance of job accessibility for those poor households with limited transportation mobility but strong needs for access to jobs.     

基于通勤特征的深圳市城中村职住关系研究

本文选取深圳市14个居住型城中村作 为案例,基于手机信令数据分析城中村的通勤特 征,探讨其与就业的职住关系模式。研究发现, 城中村的通勤特征呈现出了显著的区位差异性： 从通勤距离看,城边村最长,城内村次之,城外 村最短;从通勤方向看,城内村和区位条件较好 的城边村具有较强的市中心指向,而城外村的 通勤多局限于外围区。结合深圳的就业空间布局 特征,研究归纳了不同区位城中村的职住关系模 式,分析职住空间错配的表现,进而提出优化职 住空间格局的政策建议,包括针对不同区位的城 中村制定差异化的空间引导政策,以及在城市中 心区外培育非工业类就业中心等。     

A multi-scale analysis of urban form and commuting change in a small metropolitan area (1990–2000)

Issues of growth, especially the spatial nature of recent urban development and its implications for travel patterns, have received a great deal of attention. In particular, questions persist as to how the spatial distribution of workers and jobs influences commute patterns. This paper investigates changes in commuting and land use patterns using measures of jobs–housing balance, commuting efficiency and other statistics. A smaller urban area is chosen for study (Tallahassee, FL, USA)and data on its workers, jobs, and commute patterns are obtained from the Census Transportation Planning Package for 1990 and 2000. The key research questions investigated probe whether there were substantial changes in urban form and commuting over the period. A two-tiered approach is taken where change is explored at the regional and local scales using GIS, optimization procedures, and inferential statistical techniques. The results reveal the extent of the spatial changes in the study area between 1990 and 2000. Major findings included stability in urban structure over the time period, as well as a persistent strong relationship between land use and commute patterns. These results are discussed in light of their implications for other cities and for future work.     

Incorporating Equity Concerns into Transportation Planning and Policies in Urban China: The Status Quo of Practice and Implications

Transportation equity is one of the most recent concerns toward sustainable urban development, which aims to help municipalities or local planning authorities incorporate equity issues into transportation planning and policies, avoiding multifaceted potential inequity outcomes. As for the urbanizing China, do the mainstream planning approaches fail to take equity issues into account? What are outcomes and the potential countermeasures based on Chinese cities' spatial and policy contexts? From the perspective of transportation equity, this article aims to examine the multidimensional effects related to equity concerns of urban transportation planning and policies in China. It suggests that the municipal government should enhance the service level of public transit and efficiently address the inequity issues of transportation systems. The potential measures include: building a multi-modal transit system, linking affordable housing to the transportation system, highlighting the role of non-motorized mode, and offering proper parking spaces around transit stations.     

From the Editors

Problem: Reducing gasoline consumption could sharply curtail greenhouse gas emissions. Ongoing research seeks to document factors associated with green travel behavior, like walking and transit use.

Purpose: We seek to determine whether green beliefs and values are associated with green travel behavior. We measure whether residents of communities with environmentalist attributes drive less, consume less gasoline, and are more likely to commute by private vehicle. We explore several channels through which green beliefs and values may affect travel behavior and vice versa.

Methods: We drew our demographic, transportation, and built environment data from the 2000 Census of Population and Housing including the Public Use Microdata Sample and the 2001 National Household Travel Survey, and constructed our indicators of green ideology using voting records, political party membership, and data on hybrid auto ownership. We estimated ordinary least squares regression and linear probability models using both individual households and small areas as units of analysis.

Results and conclusions: We find green ideology is associated with green travel behavior. People with green values are more likely than others to be located in communities with high population densities and proximity to city centers and rail transit stations, which are attributes conducive to environmentally friendly travel. We also find that residents of green communities engage in more sustainable travel than residents of other communities, even controlling for demographics and the effects of the built environment. Green ideology may cause green travel behavior because greens derive utility from conservation or because greens locate in, or create, areas with characteristics that promote sustainable travel. We also discuss the possibility that green travel behavior may cause green beliefs.

Takeaway for practice: If greens self-select into dense, central, and transit-friendly areas, the demand for these characteristics may rise if green consciousness does. Alternatively, if these characteristics cause green consciousness, their promotion promises to increase green behavior. The implications of our finding that residents of green communities engage in more sustainable travel patterns than others depends on the causal mechanism at work. If greens conserve because they derive utility from it, then environmental education and persuasion may bring about more sustainable travel. Alternatively, if green travel behavior causes green beliefs, it is possible that attracting more travelers to alternate modes and reducing vehicle miles traveled may increase environmental consciousness, which may in turn promote other types of pro-environment behavior.

Research support: None.     

Travel-based residential self-selection: A qualitatively improved understanding from Norway

By integrating both quantitative and qualitative materials, this paper sheds new light on the role of travel-based residential preferences in residential location choice and the implications for land-use and travel behavior research. In the two Norwegian metropolitan areas of Oslo and Stavanger, movers who select their residence based on travel attitudes relocate to inner-city districts but not to suburban areas. For those who move to suburban areas, criteria other than travel are more important. Residential self-selection toward transit-rich neighborhoods is more prominent in the large, monocentric Oslo region than in the smaller, polycentric Stavanger metropolitan area where transit provision is generally poorer. Travel-based residential self-selection may affect the effect estimates of built environment characteristics somewhat for travel mode choice, less so for travel distance in general, and hardly at all for commuting distance. Overall, there is no strong empirical basis in support of controlling for travel-based residential self-selection in land-use and travel behavior research in a Norwegian urban context. Built environment characteristics exert substantial impacts on intra-metropolitan travel distances and modes, regardless of residential self-selection.