A New Algorithm for Graph-theoretic Nodal Accessibility Measurement

Accessibility is a useful concept in the study of the spatial structure of a region, if it can be calibrated appropriately. While graph-theoretic analysis has been used widely as a measurement scheme for the nodal accessibility in various transport networks, several limitations have been pointed out in the existing graph-theoretic accessibility measurements. This study proposes a new algorithm for deriving the nodal accessibility measure, as an attempt to improve the conventional graph-theoretic accessibility measurements. Corrections are made in such a way that irrelevant loops are excluded and relevant indirect connection paths are included selectively. In particular, the new algorithm is developed for intraurban subway networks, and includes the characteristics of intraurban subway traffic behavior. The concept of inconvenience of transfer is introduced, which is one of the most influential factors in the intraurban subway traffic. Nodal differentiation is allowed, if the nodes play different roles in the travel behavior and eventually in the accessibility. For this purpose, we employ a weighting procedure, according to which the influence of transfer on a sequence of linkages is taken into account. The new accessibility measurement scheme is then applied to the Seoul subway network. Here GIS techniques are utilized to generate accessibility surfaces from the discrete nodal accessibility values, and the changes in the spatial structure of the nodal accessibility are analyzed. Finally, based on the resulting changes in the spatial structure of accessibility in the subway network, the direction of changes in the land value and the land use pattern in Seoul is discussed.     

Accessibility Measurement in Transportation Networks and Application to the Seoul Bus System

This study presents an algorithm for measuring the time‐distance accessibility based on the flow data of actual transportation networks and examines resulting accessibility distributions. Specifically, we construct an extended graph of the transportation network to take into account not only the average speed and transfer time extracted from the data set but also various possible trajectories taken via transfers. Employing the modified Floyd algorithm which finds the shortest time distance, we compute the time‐distance accessibility of every bus stop in the Seoul bus system, which yields distinctive skew distributions. We then introduce a time‐distance cutoff to focus on effective connections and probe the emergent spatial distributions as the cutoff is varied. Revealed are the characteristic scales as well as spatial structures of the system. It is suggested that the time‐distance accessibility can serve as a significant measure to describe and predict the urban land use pattern.     

Identifying the Impacts of Land-Use Spatial Patterns on Street-Network Accessibility Using Geospatial Methods

While the land use-street network nexus is well acknowledged, evidence for the one-way impacts of land-use patterns on street accessibility is still inadequate. The measurements of land-use patterns and street accessibility lack systematic knowledge. Their empirical correlations also lack geographical variability, constraining site-specific land-use practices. Therefore, this study overcame the aforementioned limitations by examining the two-level spatial models to formulate accessibility-oriented land plans, using a well-developed Chinese city as an example. Firstly, two landscape metrics—Euclidean Nearest-Neighbor Distance (ENN) and Similarity Index (SIMI)—were used to quantify the intra- and inter-land-use configurations, respectively. Both city-level and local accessibility were measured using spatial design network analysis. Performing both ordinary least squares (OLS) and geographically weighted regression (GWR) models, results identified the statistically significant effects of inter-land-use patterns on two-level street accessibility. An exception was that land-use configurations within residential and industrial regions were irrelevant to street accessibility. We also found GWR was a better-fitting model than OLS when estimating locally-varied accessibility, suggesting hierarchical multiscale land-use planning. Overall, locally heterogeneous evidence in this study can substantialize land use-street network interactions and support the decision-making and implementation of place-specific accessibility-oriented land use.     

A Measure of Competitive Access to Destinations for Comparing Across Multiple Study Regions

Accessibility is now a common way to measure the benefits provided by transportation–land use systems. Despite its widespread use, few measurement options allow for the comparison of accessibility across multiple urban systems, and most do not adequately control for market competition between demand-side actors and supply-side facilities in localized markets. In this article, we develop a measure of competitive access to destinations that can be used to accurately compare accessibility between regions. This measure stems from spatial interaction modeling and accounts for competition at both the supply and demand sides of analysis, regional differences in transportation networks and travel behavior, and any imbalance between the size of the population and the number of opportunities. We use this method to compute access to employment for Canada's eight largest cities to comparatively examine inequalities in accessibility, both within and between cities, and by travel mode.     

Land Absorption in U.S. Metropolitan Areas: Estimates and Projections from Regional Adjustment Models

This article adapts a regional adjustment model to estimate and project the spatial outcome of population and employment growth in U.S. metropolitan areas. The three-equation multiplicative model of population change, employment change, and land absorption is estimated using three-stage least squares to account for endogeneity among the dependent variables and contemporaneous correlation across the system of equations. In addition to the core model, alternative specifications are estimated, imposing the initial conditions of size, land availability, and economic structure. The stability of the solutions is then examined using reduced-form equations estimated via the seemingly unrelated regression equations approach. The results reveal substantive evidence that population and employment growth are jointly determined, of how the two affect the outcome of land development, and, perhaps most importantly, stable and fractionally reasonable estimates at projected equilibrium points. Lastly, the adapted model controlling for the initial condition of land availability is used to project patterns of land consumption at equilibrium in 50 rapid-growth metropolitan areas.     

Primal and Dual Access

Accessibility, measuring the ease of reaching potential destinations, is increasingly being considered as an effective indicator to evaluate the performance of transport and land use interactions. Primal accessibility, a generalization of the first accessibility formulation proposed by Hansen, has been widely used in many studies and demonstrated to be a reliable tool for project, program, and policy evaluation. The dual of accessibility, measuring the time required to reach a given number of opportunities, is less often considered but can be used for optimization in location covering-type problems. This article, hence, clarifies the definitions of primal and dual access, and applies both measures to the Minneapolis—St. Paul metropolitan area for auto and transit to demonstrate their practicality as a metropolitan-level measurement. We explore the correlations and differences between the primal and dual access to better understand the relative strengths of the measures. It is found that, as with primal accessibility, dual accessibility is an efficient approach to evaluate accessibility, which is straightforward to calculate and to explain to policy-makers and the public.     

THE LOCATIONAL DYNAMICS OF MANUFACTURING IN CHINA'S COUNTIES: INFLUENCE OF EXPRESSWAY INVESTMENT

This study investigates the impact of expressway investment in China's counties. By identifying expressway accessibility through toll station locations, we estimate the manufacturing distribution along expressways for 2001–2005. We find that expressway accessibility promotes manufacturing employment for inland counties by around 41 percent; however, for coastal counties that already have high road density and dense manufacturing layouts, the returns from new expressways are small. Furthermore, counties close to large cities benefit more from expressway accessibility than do counties that are far from them. The gap first increases in the period of expressway construction and then decreases as expressway effects are smoothed.     

Capital Assistance for Small Firms: Some Implications for Regional Economic Welfare

This paper analyzes the role of finance capital in regional economic development. A cost‐benefit approach is invoked in order to estimate the welfare impacts of a regional loan and guarantee program for small firms in Israel. Program‐created employment is treated as a benefit and an employment account that separates net from gross employment, is presented. An estimate of net wage benefits is then derived. This involves adjusting wages across different earnings classes in order to account for the variation in opportunity costs of labor at different levels. The estimation of costs includes the opportunity costs of capital, administration, default, and tax‐raising costs. Results point to substantial regional welfare effects. We stress the need to account for changing regional economic structure in this kind of evaluation framework.     

农用地集约利用与农产品消费市场可达性关系研究——以江苏兴化市为例

基于农用地集约利用和市场可达性评价方法,计算了兴化市各乡镇农用地集约利用程度和农产品消费市场可达性并通过统计方法初步分析了两者的关系。结果表明:(1)农用地集约利用程度与农产品消费市场可达性具有明显的空间差异;(2)农用地集约利用程度与农产品消费市场可达性之间的秩相关系数为0.23,在α=0.05的置信水平上相关关系不显著,这说明县域尺度下农业用地集约利用与农产品消费市场可达性之间的空间模式已经突破了传统的"农产品消费市场可达性-农业生产方式-农用地集约利用程度"农业区位论模式。     

公交站点可达性测度及其在停车分区中的应用

考虑公交与小汽车方式间的可达性差异,提出了依据公交服务水平调控小汽车可达性的停车分区思路,以期实现对小汽车方式的合理限制,支持城市公交优先发展。首先根据居民出行对不同类型公交站点具有不同可达性需求,将以需求点为圆心、站点时空可接近距离为半径的覆盖范围作为基本分析单元,构建基于微观个体时空约束下的公交站点可达性测度模型。其次借助ArcGIS,以昆明市公交网络数据为基础,对站点可达性空间分布特征进行可视化分析,所得结果与城市用地开发整体特征相吻合,验证了模型的合理性。最后以公交可达性水平为主要依据划分停车供给分区,从而对不同分区停车泊位供给的科学配置提供支撑。     

RECESSIONARY SHOCKS AND REGIONAL EMPLOYMENT: EVIDENCE ON THE RESILIENCE OF U.K. REGIONS*

ABSTRACT We analyze the resilience of U.K. regions to employment shocks. Two basic notions of resilience are distinguished. With engineering resilience, there is an underlying stable growth path to which a regional economy rebounds following a shock. With ecological resilience, shocks can permanently affect the growth path of the regional economy. Our data set consists of quarterly employment series for 12 U.K. regions (NUTS I) for the period 1971–2010. Using a seemingly unrelated regression (SUR) model specification, we test for the relevance of (engineering) resilience of U.K. regional employment to the four recessionary shocks in our sample. It turns out that U.K. regions do indeed differ in their resilience, but that these differences mainly concern the initial resistance to these shocks and not so much the recovery stage. The SUR model does not allow shocks to have permanent effects and it also does not take the possibility of time differentiated shock spillovers between the 12 regions into account. To this end, we also estimate a vector error‐correction model (VECM) specification where employment shocks can have permanent effects and where also interregional employment linkages are included. We find that employment shocks typically have permanent effects when it concerns the own‐region effects. Permanent effects can also be found for the impact on other regions but the interregional effects are typically only significant for nearby regions.     

公共交通可达性分析方法进展

公共交通可达性拥有空间属性、时间属性、社会属性和经济属性,它是一种衡量区位价值的综合性指标,不仅可以反映城市空间特征,同时对城市中生活的人的社会经济属性和生活习惯,具有一定的解释力。为了不断适应新形势下的交通发展要求,减少环境负担,早日实现低碳绿色发展,创新公交都市规划与分析方法迫在眉睫。本文对基于个人的、基于效用的、基于基础设施的和基于位置的可达性研究进行了回顾,并归纳了七种公共交通可达性的分析方法,分别为：基于缓冲区的公共交通站点可达性、基于供需模型的公共交通面状可达性、基于网络分析法的公共交通网络可达性、基于成本栅格法的公共交通可达性、基于成本栅格与网络分析的集成法的公共交通可达性、基于高性能图形数据库的公共交通高精度可达性、基于开放地图 API 的公共交通高精度可达性。 以期为我国未来公共交通可达性的分析方法提供指引和借鉴。     

Measuring Accessibility for People with a Disability

This paper discusses some of the inherent problems associated with measuring accessibility for people on a landscape of surfaces, barriers, and travel modes. Along with this discussion we propose a new perspective for measuring accessibility with a focus on people with differing abilities. Even though our focus is on people with a physical disability, such an approach can be easily extended and is able to be generalized to other needs and differences. Traditional measurements of accessibility are flawed, as they fail to directly account for mobility and physical differences among people. They ignore structural barriers and individual mobility limitations that affect travel time, effort, and even successful completion. To make sense of this dilemma, we propose an accessibility measurement framework that includes measures of absolute access, gross access, closest assignment access, single and multiple activity access, probabilistic choice access, and relative access. Most of these measures of access have been proposed by others, but our framework attempts to codify an approach that helps to overcome weaknesses in using only the absolute access measurement currently used in ADA compliance. Such measures can be used to map accessibility as well as to help select the mitigation or renovation projects that yield the greatest increase in accessibility for people with disabilities. We argue that for many urban and building design problems providing absolute access for people with physical disabilities should be accompanied by the use of a relative access measurement, so that removing barriers can be done in the order that provides the greatest improvement in access for a given level of expenditure.     

基于网络分析的交通网络评价及其与区域经济发展关系研究

以网络分析为基础,使用节点连通性和可达性等指标,评价研究甘肃省的交通网络以及交通网络与区域经济发展之间的内在关系,提出了平均经济--网络直径概念、功能及其计算方法。研究结果表明,节点连通性和可达性指标与区域经济发展水平具有密切的相关性,且跨区域交通对区域经济发展的贡献率大于仅邻域交通对区域经济发展的贡献率;使用节点连通性和可达性指标可界定出各区域经济之间的空间相互作用范围,为整个区域的交通规划和经济区划提供有力的科学依据;甘肃省交通呈聚团模式,具有空间自相关性。     

Gender Ideology in Historical Reconstruction: A Case Study from the 1930s

You are probably aware of the fact that homes are being wrecked daily due to the fact that married women are permitted to work in factories and offices in this land of ours. You and we all know that the place for a wife and mother is at home, her palace. The excuse is often brought up that the husband cannot find employment. It is the writers’ belief that if the women were expelled from places of business,…these very men would find employment. These same womens’ husbands would naturally be paid a higher salary, inasmuch as male employees demand a higher salary than females.¹     

南京市区就业空间布局研究

本文采取就业密度分析方法,对南京市区就业空间布局进行实证研究。在南京市区现有11个区的基础上将南京市区划分为159个研究单元。依据2005年南京市1%人口抽样调查资料中"区县层面"分行业就业数据,以及2006年南京市用地现状图,修正匹配得到各个研究单元制造业、服务业、商业金融业及总的就业密度值。并运用Arcgis软件对就业密度值进行核密度分析以及3D模拟,分析南京市区制造业、服务业以及总就业的空间布局特征及原因机制。     

Space-Time and Integral Measures of Individual Accessibility: A Comparative Analysis Using a Point-based Framework

Conventional integral measures of accessibility, although valuable as indicators of place accessibility, have several limitations when used to evaluate individual accessibility. Two alternatives for overcoming some of the difficulties involved are explored in this study. One is to adapt these measures for evaluating individual accessibility using a disaggregate, nonzonal approach. The other is to develop different types of measures based on an alternative conceptual framework. To pursue the former alternative, this study specifies and examines eighteen gravity-type and cumulative-opportunity accessibility measures using a point-based spatial framework. For the latter option, twelve space-time accessibility measures are developed based on the construct of a prism-constrained feasible opportunity set. This paper compares the relationships and spatial patterns of these thirty measures using network-based GIS procedures. Travel diary data collected in Columbus, Ohio, and a digital data set of 10,727 selected land parcels are used for all computation. Results of this study indicate that space-time and integral indices are distinctive types of accessibility measures which reflect different dimensions of the accessibility experience of individuals. Since space-time measures are more capable of capturing interpersonal differences, especially the effect of space-time constraints, they are more “gender sensitive” and helpful for unraveling gender/ethnic differences in accessibility. An important methodological implication is that whether accessibility is observed to be important or different between individuals depends heavily on whether the measure used is capable of revealing the kind of differences the analyst intends to observe.     

The Location Choice of Employment‐based Immigrants among U.S. Metro Areas*

Abstract. This paper examines the initial location choice of legal employment‐based immigrants to the United States using Immigration and Naturalization Service data on individual immigrants, as well as economic, demographic, and social data to characterize the 298 metropolitan areas we define as the universal choice set. Focusing on interactions between place characteristics and immigrant characteristics, we provide multinomial logit model estimates for the location choices of about 38,000 employment‐based immigrants to the United States in 1995, focusing on the top 10 source countries. We find that, as groups, immigrants from nearly all countries are attracted to large cities with superior climates, and to cities with relatively well‐educated adults and high wages. We also find evidence that employment‐based immigrants tend to choose cities where there are relatively few immigrants of nationalities other than their own. However, when we introduce interaction terms to account for the sociodemographic characteristics of the individual immigrants, we find that the estimated effects of location destination factors can reverse as one takes account of the age, gender, marital status, and previous occupation of the immigrants.     

THE REGIONAL MALL IN CANADA

Over the last three decades, regional shopping malls have become significant features of the Canadian urban landscape. They account for the largest concentrations of employment, retail sales, and trip destinations outside the central business district, and they reshape patterns of accessibility within communities. This article examines the number, economic role, location, and implication of these facilities, in Canada, and contrasts them with similar malls in the United States. By 7 986, there were 84 regional malls with more than 500 000 sq. ft. of space in Canada, and these malls accounted for 10 per cent of all retail sales.     

Strengths and weaknesses of accessibility instruments in planning practice: technological rules based on experiential workshops

Accessibility instruments can play a valuable role in urban planning practice by providing a practical framework for exploring and testing relationships between land use and transport infrastructure. Despite many available accessibility instruments, they are still not widely used in planning practice. This paper explores the background of this problem by examining the findings of a EU-funded study on the usability and usefulness of existing accessibility instruments. The study applied 16 instruments in local planning contexts according to a standardized process protocol. The outcomes of these so-called experiential workshops were analysed through a standardized measurement protocol, which included participant observation along with pre- and post-workshop practitioner questionnaires. This broad investigation presents a rich analytical tool for understanding how different types of accessibility measures, spatial resolutions of output and levels of comprehensiveness affect usability and usefulness. Based on this we propose 10 technological rules that (a) can be used directly in practice to improve usability of accessibility instruments and (b) can provide hypotheses to be examined in further academic studies. Our results suggest that instead of striving for the ultimate accessibility measure, it would be more effective to identify which measures could successfully serve different user needs in accessibility planning.