JTG Special Section on Accessibility and Socio-Economic Activities: Methodological and Empirical Aspects (original) (raw)
Guest Editorial: New Frontiers in Accessibility Modelling: An Introduction
Networks and Spatial Economics, 2011
There is a well established body of research that deals with how accessibility affects land use planning and spatial interaction. Hansen (1959) is usually cited as the father of this "scientific term". In his seminal work, he defines accessibility as "the potential of opportunities for interaction" (p.73). Since then, the interest of how transport systems and spatial interaction are related has grown exponentially and accessibility analysis has played for more than five decades a central role in the agenda of regional and transport research. The concept of accessibility is open to different areas of study regarding the activities that can be carried out, to multiple transport systems and to different individuals or groups, so it is not surprising that in the literature we can find many different definitions (Geurs and van Wee 2004; Bruinsma and Rietveld 1998; Reggiani 1998; Vickerman 1995; and Morris et al. 1979). Handy and Niemeier (1997) showed that different types of accessibility measures exist according to particular criteria, and it is difficult to suggest the best approach to measure accessibility because different situations and purposes demand different approaches. This comment is quite pertinent at the light of the articles included in our special issue. We will see that four of them analyze accessibility in commuting and the authors use different methods, demarcation areas and opportunities are in some cases aggregated at the level of areas or individuals. In the last decade with the continuing development and deployment of geographic information systems (GIS) and other geospatial technologies that have greatly enhanced the ability to collect and analyse data relevant to accessibility analysis, researchers, in some cases, have changed from place-based measures of accessibility
An overview of accessibility measures
This paper presents a review of accessibility measures in transportation studies by addressing its conceptual framework, data requirements, and applications. Depending on the theoretical basis, the accessibility measures are classified in infrastructure, location, gravity, space-time and utility-based measure. A system approach is applied to identify the relations among the interacting variables: land-use, transportation, temporal and individual ones. The criteria, including theoretical basis, interpretability, and data requirements are used to evaluate these measures. Recent progress in accessibility studies point towards the inclusion of more individual's spatial-temporal accessibility measure (using the space-time prism concept) but the data requirements, and interpretability of this measure remain as a problem. Furthermore, most of the measures fail for not considering the competition for opportunities (e.g. jobs on the employment market), and it seems to be the main issue for the development of more realistic accessibility measures.
Why accessibility measurement is not merely an option, but an absolute necessity
Many authors and advocates have argued over the past decades that the traditional mobility-centered approach to transportation planning needs to be replaced with an accessibility-centered approach. But while the interest in accessibility is on the rise, in practice transportation (and land use) systems still tend to be evaluated using traditional mobility-centered performance indicators, like the level-of-service criterion or travel time savings. The aim of this chapter is to provide an argument that the assessment of accessibility is not merely an option, but an absolute necessity. The paper starts by distinguishing three, partly overlapping, goals of transportation planning: activity participation, economic development, and environmental quality. Subsequently, the interrelationship between accessibility measurement, accessibility indicators, and each of these goals is explored. That exploration leads to the conclusion that the measurement of accessibility is not of intrinsic value if policy makers seek to promote economic development or environmental quality. While accessibility is related to both goals, other performance indicators may be more suitable if decision-makers are interested in advancing either goal. The analysis results in a radically different, and perhaps counter-intuitive, conclusion regarding the goal of activity participation: if decision-makers are interested in the goal of activity participation, it would be fundamentally wrong to measure a transportation (and land use) system’s contribution to actual activity participation. The goal of activity participation requires measurement of accessibility, as only by doing so it is possible to account for persons’ constitutive interests in the range of states they can achieve. Hence, the conclusion that accessibility measurement is not merely an option but an absolute necessity, if decision-makers want to take the constitutive interests of persons seriously in the design of transportation systems.
Measuring accessibility: a review and proposal
Environment and Planning A 11(3) (1979), 299 – 312.
An attempt is made to clarify some of the confusion about the notion of accessibility by examining the limitations, strengths, and conceptual bases of distance, topological, gravity, and cumulative-opportunity measures of accessibility. In their aggregate and disaggregate states the measures are practical, enabling measurement into the future and measurement with a minimum of data, but the assumptions that all nodes are potential destinations and that all origins are known severely restrict the meaning and uses of the measures. Time - space measures of accessibility do not make these assumptions although they are data hungry, retrospective, and share with the other measures the narrow conception of accessibility as a property of the built environment. It is proposed that accessibility be thought of as a vacancy in an activity routine and that it be measured in terms of the disruption involved in creating it.
Accessibility analysis and transport planning: an introduction
Edward Elgar Publishing eBooks, 2012
Accessibility is a concept that has become central to physical planning during the last 50 years; improving accessibility is an aim which has now made its way into mainstream transport planning and policy-making worldwide. Batty (2009) traces the origins of the concept back to the 1920s. It was used in location theory and regional economic planning, becoming important once transport planning began, mainly in North America where it was associated with transport networks and trip distribution patterns. Its conceptual basis dates back further. , in his classic and much cited exposé, 'How accessibility shapes land use', rolled out our fi rst real defi nition: the potential for interaction (based on the notion of potential traced back to the social physics school in the nineteenth century). In recent decades, the term 'accessibility' has marshalled renewed interest from civil engineering, geography, spatial economics and other academic fi elds to uncover a variety of new measures. This book's purpose is relatively straightforward. It marries advancing approaches in accessibility research and modelling with best practices in accessibility planning and evaluation -to better support integrated transport and land-use policy-making in Europe and the United States. In the 2000s considerable progress has been made along these fronts. These advances have taken diff erent directions. First, there is a continuing trend of more complex and disaggregated accessibility measures, largely in response to recognizing that aggregate measures fail to account for the wide variation in individual behaviour and population groups at diff erent spatial scales. These trends partly result from improvements in techniques to construct location-based accessibility indicators. These techniques have evolved from simple calculations to complex and detailed methods that use algorithms within a geographic information system (GIS) platform to extract and assemble data from multiple spatial databases at fi ne levels of spatial resolution (e.g., see . Measuring
Accessibility Long Term Perspectives
Journal of Transport and Land Use, 2008
Improved accessibility and its correlate lower generalized cost of contact, travel and transport have been sought by dynamic human societies for their economic and social bene ts throughout recorded history. e paper will re ect about this process at a number of different spatial and temporal scales based on a conceptual model. Looking back at European history, it will trace the interaction between Christaller's logic of local market areas and the idea of (low contact cost) network cities. Focusing on Switzerland since 1950 it will show how network investment changed the relative distribution of population and employment and how this interacted with changes in the preferences of the travelers. Using a recent snapshot of how a substantial sample of Swiss maintain their social networks over often very large areas, it will try to answer the question of what will happen in the future, if the current trend of ever lower costs of contact persists.
Urban accessibility: the paradox, the paradigms and the measures. A scientific review
Tema. Journal of Land Use, Mobility and Environment, 2020
TeMA is the Journal of Land Use, Mobility and Environment and offers papers with a unified approach to planning, mobility and environmental sustainability. With ANVUR resolution of April 2020, TeMA journal and the articles published from 2016 are included in the A category of scientific journals. From 2015, the articles published on TeMA are included in the Core Collection of Web of Science. It is included in Sparc Europe Seal of Open Access Journals, and the Directory of Open Access Journals. The The Times They Are a-Changin' and cities have to face challenges which may not be further postponed. The three issues of the 13th volume will collect articles concerning the challenges that cities are going to face in the immediate future, providing readings and interpretations of these phenomena and, mostly, methods, tools, technics and innovative practices (climate proof cities, zero consumption cities, car free cities) oriented to gain and keep a new equilibrium between cities and new external agents.
Accessibility: a useful analytical and empirical tool in spatial economics – experiences from Sweden
2013
Accessibility has for many years been a widely used tool in transportation research. Many definitions have been suggested and researchers have constructed numerous mathematical formulations to measure its value to be able to evaluate the relationships between the nature of the transport systems and the patterns of land use. Such correlations have been used especially in assessing existing transport systems and forecasting their performance to provide decision-makers with ideas about the need for investments in the transport systems. However, accessibility measures can be regarded as the spatial counterparts of discounting. The measures represent the spatial distribution of economic agents and their activities in a simple way that imposes a very clear structure upon the relationship between these agents and their activities and their environment. Various frictional effects arising from geographical distance between economic agents determine their interaction options, i.e., their opti...
Accessibility measures from an equity perspective
In recent years, there has been an increasing interest in accessibility measures as a performance indicator of transport systems and, sometimes, of integrated land-use and transport interventions, in both academia and practice. This development is more than the replacement of one performance indicator, typically the level-of-service indicator as used in much of mainstream transport planning, by another. The level-of-service indicator was applied to a transport network or parts thereof. In contrast, accessibility measures inevitably apply to the users of the transport system. They generate insight into the level of accessibility for specific users groups, whether by geographical location, mode availability, income, race, or travel motive (work, leisure, business, freight). As a consequence, the shift towards accessibility measures inevitably, and much more overt than in the case of mainstream transportation planning, directs the attention to the distributive question in transport: who reaps the accessibility benefits from investments in the transport system (Talen and Anselin, 1998)? As the distributive question is highly political, so is the use of accessibility measures. Different measures may result in different distributive patterns and hence point to different policy responses. This does not imply, however, that the choice of an accessibility measure is merely a political issue. Rather, we argue that the choice for a certain accessibility measure should be based on a clear understanding of the responsibility of both government and transport system user for the level of accessibility of that user.
2014
One of the core objectives of urban planning practice is to provide spatial equity in terms of opportunities and use of public space and facilities. Accessibility is the element that serves this purpose as a concept linking the reciprocal relationship between transport and land use, thus shaping individual potential mobility to reach the desired destinations. Accessibility concepts are increasingly acknowledged as fundamental to understand the functioning of cities and urban regions. Indeed, by introducing them in planning practice, better solutions can be achieved in terms of spatial equity. The COST Action TU1002 "Accessibility instruments for planning practice" was specifically designed to address the gap between scientific research in measuring and modelling accessibility, and the current use of indicators of accessibility in urban planning practice. This paper shows the full process of introducing an easily understandable measure of accessibility to planning practitio...
Evaluating the Impacts of Transportation Plans Using Accessibility Measures
2011
Despite a growing awareness of the social and environmental impacts of transportation infrastructure, most transport plans aim to increase mobility while paying little attention to accessibility. The shift to plannning for accessibility has been hampered by a lack of clear demonstrations of the usefulness of accessibility as a goal and norm for transportation planning. The purpose of this paper is to provide such a demonstration of the feasibility and value of accessibility evaluations with an analysis of Montréal's Transportation Plan. It shows how accessibility can be used by planners as a performance measure to evaluate a plan as a whole and to assess whether its goals will be attained, and/or to evaluate the plan on a project-by-project basis. L'ÉVALUATION DES PLANS DE TRANSPORT GRÂCE AUX MESURES D'ACCESSIBILITÉ Résumé Malgré une reconnaissance accrue des impacts sociaux et environnementaux des infrastructures de transport, la plupart des plans de transport visent à augmenter la mobilité et donnent peu d'attention à l'accessibilité. Dans la pratique, le passage d'une planification axée sur la mobilité à une planification axée sur l'accessibilité a été lent, en partie à cause d'un manque de démonstrations claires de l'utilité de l'accessibilité comme objectif et comme mesure dans la planification des transports. Le but de ce travail est d'offrir une telle démonstration de la faisabilité et valeur de l'évaluation de l'accessibilité grâce à une analyse du Plan de transport de Montréal. Il montre comment l'accessibilité peut être utilisée par les urbanistes et planificateurs comme mesure de performance, d'une part, pour évaluer un plan dans son ensemble et estimer la mesure dans laquelle il permettra d'atteindre des objectifs de durabilité sociale et environnementale et, d'autre part, pour évaluer un plan sur la base des projets individuels qu'il contient.
Accessibility measures: formulation considerations and current applications
2000
16. Abstract This report examines micro-scale and macro-scale factors for inclusion in an ideal accessibility measure. Their potential influence on the evaluation of mode choice and destination choice is discussed. Availability in Texas, major cities is presented, as well as the subjective nature of the factors. In addition, an evaluation of accessibility measures currently in use is presented.
Accessibility and potential mobility as a guide for policy action
In this paper, I present a framework to simultaneously assess the accessibility provided by a transport-land use system and the potential mobility provided by the transport system. This framework provides a novel approach to identify ‘the’ transport problem in modern societies. It thus provides a framework that could serve as the basis for transportation planning and urban planning. In contrast to traditional approaches to transportation planning, it does not focus on the quality of the transportation network as such, but on the ultimate goal of a transport network: to enable people to participate in out-of-home activities. In contrast to the vast body of literature on accessibility measures, it provides a clear framework to determine when an intervention in the transport network is called for and when such an intervention is unlikely to deliver results.
Accessibility evaluation of land-use and transport strategies: review and research directions
Journal of Transport Geography, 2004
A review of accessibility measures is presented for assessing the usability of these measures in evaluations of land-use and transport strategies and developments. Accessibility measures are reviewed using a broad range of relevant criteria, including theoretical basis, interpretability and communicability, and data requirements of the measures. Accessibility impacts of land-use and transport strategies are often evaluated using accessibility measures, which researchers and policy makers can easily operationalise and interpret, such as travelling speed, but which generally do not satisfy theoretical criteria. More complex and disaggregated accessibility measures, however, increase complexity and the effort for calculations and the difficulty of interpretation. The current practice can be much improved by operationalising more advanced location-based and utility-based accessibility measures that are still relatively easy to interpret for researchers and policy makers, and can be computed with state-of-the-practice data and/or landuse and transport models. Research directions towards theoretically more advanced accessibility measures point towards the inclusion of individual's spatial-temporal constraints and feedback mechanisms between accessibility, land-use and travel behaviour. Furthermore, there is a need for theoretical and empirical research on relationships between accessibility, option values and non-user benefits, and the measurement of different components of accessibility.
Geographical Analysis, 2003
Analytical methods for evaluating accessibility have been based on a spatial logic through which the impedance of distance shapes mobility and urban form through processes of locational and travel decision making. These methods are not suitable for understanding individual experiences because of recent changes in the processes underlying contemporary urbanism and the increasing importance of information and communications technologies (ICTs) in people's daily lives. In this paper we argue that analysis of individual accessibility can no longer ignore the complexities and opportunities brought forth by these changes. Further, we argue that the effect of distance on the spatial structure of contemporary cities and human spatial behavior has become much more complicated than what has been conceived in conventional urban models and concepts of accessibility. We suggest that the methods and measures formulated around the mid-twentieth century are becoming increasingly inadequate for grappling with the complex relationships among urban form, mobility, and individual accessibility. We consider some new possibilities for modeling individual accessibility and their implications for geographical analysis in the twenty-first century.
Accessibility: Review of measuring techniques and their application
2000
Integrated transport policy aims to improve travel choices; and accessibility measurements have the potential to provide an indicator of whether these aims are being achieved. Accessibility measures seek to define the level of opportunity and choice taking account of both the existence of opportunities, and the transport options available to reach them. Good accessibility as a transport objective also carries very broad support from every strand of opinion within society. There are therefore very practical advantages in demonstrating the effects of transport projects and plans in terms of accessibility.