Integrating people and place: A density-based measure for assessing accessibility to opportunities
28 Jul 2014-Journal of Transport and Land Use (Journal of Transport and Land Use)-Vol. 7, Iss: 2, pp 23-40
TL;DR: The goal here is to understand the magnitude and nature of the opportunities a mobile object had access to, given known location points and a time budget for its movement.
Abstract: Mobile object analysis is a well-studied area of transportation and geographic information science (GIScience). Mobile objects may include people, animals, or vehicles. Time geography remains a key theoretical framework for understanding mobile objects' movement possibilities. Recent efforts have sought to develop probabilistic methods of time geography by exploring questions of data uncertainty, spatial representation, and other limitations of classical approaches. Along these lines, work has blended time geography and kernel density estimation in order to delineate the probable locations of mobile objects in both continuous and discrete network space. This suite of techniques is known as time geographic density estimation (TGDE). The present paper explores a new direction for TGDE, namely the creation of a density-based accessibility measure for assessing mobile objects' potential for interacting with opportunity locations. As accessibility measures have also garnered widespread attention in the literature, the goal here is to understand the magnitude and nature of the opportunities a mobile object had access to, given known location points and a time budget for its movement. New accessibility measures are formulated and demonstrated with synthetic trip diary data. The implications of the new measures are discussed in the context of people-based vs. placed-based accessibility analyses.
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10 Sep 2019
TL;DR: A spatiotemporal accessibility model is proposed by extending classical STPs to non-normal stochastic urban networks and blending this modified STP with the attractiveness of urban opportunities to assess the accessibility of its traffic analysis zones to Kowsar discount retail markets.
Abstract: Space-time prism (STP) is a comprehensive and powerful model for computing accessibility to urban opportunities. Despite other types of accessibility measures, STP models capture spatial and temporal dimensions in a unified framework. Classical STPs assume that travel time in street networks is a deterministic and fixed variable. However, this assumption is in contradiction with the uncertain nature of travel time taking place due to fluctuations and traffic congestion. In addition, travel time in street networks mostly follows non-normal probability distributions which are not modeled in the structure of classical STPs. Neglecting travel time uncertainty and disregarding different types of probability distributions cause unrealistic accessibility values in STP-based metrics. In this way, this paper proposes a spatiotemporal accessibility model by extending classical STPs to non-normal stochastic urban networks and blending this modified STP with the attractiveness of urban opportunities. The elaborated model was applied on the city of Isfahan to assess the accessibility of its traffic analysis zones (TAZs) to Kowsar discount retail markets. A significant difference was found between the results of accessibility values in normally and non-normally distributed networks. In addition, the results show that the northern TAZs had larger accessibility level compared to the southern ones.
3 citations
Cites background from "Integrating people and place: A den..."
...As combining magnitude or attractiveness of opportunities with reachable places can model accessibility [68,74], reliable space-time accessibility measure is defined through Equation (3), where A k (α) is the accessibility of a person or population group q conducting a trip with origin r and destination s to opportunity k located in graph G at confidence interval αq....
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TL;DR: In this article, the authors focus on location choice modeling underlying activity-travel behavior and include five manuscripts that were originally presented in Toronto, Canada, at the Thirteenth International Conference on Travel Behaviour Research (IATBR).
Abstract: This special section of the Journal of Transport and Land Use focuses on location choice modeling underlying activity-travel behavior and includes five manuscripts that were originally presented in Toronto, Canada, at the Thirteenth International Conference on Travel Behaviour Research, organized by the International Association for Travel Behaviour Research (IATBR). This collection of works contributes to the growing literature on location choice modeling with innovations in modeling approaches and spatial measurement techniques, as well as notable advancements in the development of theories and conceptual frameworks. The five papers tackle a spectrum of location choice issues, including the op erationalization of residential location variables, the accessibility of moving objects to locations of interest, model transferability in the temporal dimension, spatial self-selection and the roles of attitudinal and socioeconomic characteristics, and integration of location choice into microscopic travel demand simulation. In “The role of location in residential location choice models: A review of literature,” Patrick Schirmer, Michael van Eggermond, and Kay Axhausen present a new classification system to categorize location variables and assess the various ways in which they have been operationalized in residential discrete choice models. Residential alternatives have been modeled at different spatial aggregation levels, from zones or neighborhoods to disaggregated units such as buildings or dwellings. The authors orga nize the wide range of measurements used to define residential location at different aggregation levels into four main categories—built environment, points of interest, socioeconomic environment, and accessibility—and synthesize recent findings by comparing different analysis approaches and highlighting common location attributes measured and used between studies. While Schirmer et al. highlight common approaches for measuring accessibility in the context of residential location choice, Mark Horner and Joni Downs develop a new accessibility measure for mobile objects (e.g., vehicles) in “Integrating people and place: A density-based measure for assessing accessibility to opportunities.” The metric, which builds on earlier work by the authors concerning time-geographic density estimation, estimates how accessible a moving object is to locations of interest given constraints on its movement. Using synthetic activity-travel data for 11 individuals, a road network, and job counts for census blocks, Horner and Downs demonstrate the use of their metric within the context of Leon County, Florida. The analysis clearly shows how the metric bridges “people-based” and “place-based” measures of accessibility. An important assumption of travel forecast models is that parameters estimated from observed behavior in the base year are applicable for predicting future behavior; this is known as model transferability in the temporal dimension. James Fox, Andrew Daly, Stephane Hess, and Eric Miller examine this assumption and assess the degrees to which it is valid in, “Temporal transferability of models of mode-destination choice for the Greater Toronto and Hamilton area.” Using cross-sectional data from the same travel survey administered in different years during a 20-year period, Fox et al. developed three different model specifications and evaluated their temporal transferability with three tests. Not only does this paper provide insights on improving model transferability and recognizing limitations over
3 citations
TL;DR: In this article , the authors investigate inequalities in accessibility in São Paulo from an individual-based perspective, adopting a methodological approach that overcomes the high computational and data requirements that typically hinder large-scale applications of individual based accessibility metrics.
2 citations
01 Jan 2021
TL;DR: In this paper, accessibility is defined as the ease with which people are able to reach the goods and services necessary to sustain their basic needs, and is viewed as a product of the interplay between urban form, transportation systems, and the alternatives they provide.
Abstract: Cities represent complex arrangements of people and infrastructures, interacting in myriad ways. Although transportation and other mobility technologies have reduced frictions of distance and facilitated greater connectivity of people with their needs, the underlying physical structure of the city itself remains a key determinant in shaping activity outcomes. This chapter examines the interplay of cities, urban form, and the implications for accessibility. Accessibility is the ease with which people are able to reach the goods and services necessary to sustain their basic needs. In this way, accessibility is viewed as a product of the interplay between urban form, transportation systems, and the alternatives they provide, and other factors. Several considerations are reviewed in understanding accessibility and urban form, and then the past is traced before examining key contemporary themes at the nexus of urban form and accessibility. The chapter concludes by identifying several areas prime for further inquiry and exploration moving forward.
2 citations
TL;DR: In this article, the authors study the mobility laws of location-based games and find that the characteristics governing personal mobility remain consistent with a truncated Levy-flight model and that the increase can be explained by a larger number of short-hops, i.e., individuals explore their local neighborhoods more thoroughly instead of actively visiting new areas.
Abstract: Mobility is a fundamental characteristic of human society that shapes various aspects of our everyday interactions. This pervasiveness of mobility makes it paramount to understand factors that govern human movement and how it varies across individuals. Currently, factors governing variations in personal mobility are understudied with existing research focusing on explaining the aggregate behaviour of individuals. Indeed, empirical studies have shown that the aggregate behaviour of individuals follows a truncated Levy-flight model, but little understanding exists of the laws that govern intra-individual variations in mobility resulting from transportation choices, social interactions, and exogenous factors such as location-based mobile applications. Understanding these variations is essential for improving our collective understanding of human mobility, and the factors governing it. In this article, we study the mobility laws of location-based gaming—an emerging and increasingly popular exogenous factor influencing personal mobility. We analyse the mobility changes considering the popular PokemonGO application as a representative example of location-based games and study two datasets with different reporting granularity, one captured through location-based social media, and the other through smartphone application logging. Our analysis shows that location-based games, such as PokemonGO, increase mobility—in line with previous findings—but the characteristics governing mobility remain consistent with a truncated Levy-flight model and that the increase can be explained by a larger number of short-hops, i.e., individuals explore their local neighborhoods more thoroughly instead of actively visiting new areas. Our results thus suggest that intra-individual variations resulting from location-based gaming can be captured by re-parameterization of existing mobility models.
1 citations
References
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TL;DR: The Kernel Method for Multivariate Data: Three Important Methods and Density Estimation in Action.
Abstract: Introduction. Survey of Existing Methods. The Kernel Method for Univariate Data. The Kernel Method for Multivariate Data. Three Important Methods. Density Estimation in Action.
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"Integrating people and place: A den..." refers background in this paper
...Note that this does not express the raw probability of finding the object at a location; rather it provides a relative measure of that likelihood, which that can be directly compared across all locations in the map (Silverman 1986)....
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01 Jan 1970
3,730 citations
TL;DR: In this article, an empirical analysis of the residential development patterns illustrates that accessibility and the availability of vacant developable land can be used as the basis of a residential land use model.
Abstract: An empirical examination of the residential development patterns illustrates that accessibility and the availability of vacant developable land can be used as the basis of a residential land use model. The author presents an operational definition and suggests a method for determining accessibility patterns within metropolitan areas. This is a process of distributing forecasted metropolitan population to small areas within the metropolitan region. Although the model presented is not yet sufficiently well refined for estimating purposes, the concept and the approach may be potentially useful tools for metropolitan planning purposes.
2,954 citations
"Integrating people and place: A den..." refers background in this paper
...…approaches (Levine et al. 2012; Neutens, Schwanen, and Witlox 2011; Li et al. 2011; Harris 2001; Miller 1999; Burns 1979; Weibull 1976; Ingram 1971; Hansen 1959; Shen 1998)While precise definitions vary across disciplines and analytical contexts, generally accessibility is thought to mean the ease…...
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...Accessibility-related research has thrived during the last few decades, with new data and computational tools facilitating innovations rooted in classical approaches (Levine et al. 2012; Neutens, Schwanen, and Witlox 2011; Li et al. 2011; Harris 2001; Miller 1999; Burns 1979; Weibull 1976; Ingram 1971; Hansen 1959; Shen 1998)While precise definitions vary across disciplines and analytical contexts, generally accessibility is thought to mean the ease with which activities can be reached in space....
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TL;DR: In this article, the authors provide a framework for the development of accessibility measures and two case studies suggestive of the range of possible approaches are presented, as well as issues that planners must address in developing an accessibility measure.
Abstract: Accessibility is an important characteristic of metropolitan areas and is often reflected in transportation and land-use planning goals. But the concept of accessibility has rarely been translated into performance measures by which policies are evaluated, despite a substantial literature on the concept. This paper is an attempt to bridge the gap between the academic literature and the practical application of such measures and provide a framework for the development of accessibility measures. Issues that planners must address in developing an accessibility measure are outlined, and two case studies suggestive of the range of possible approaches are presented.
1,437 citations