Geographical Analysis (1998) 30(3): 191-216.

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

Mei-Po Kwan

Abstract:  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, non-zonal approach. The other is to develop different types of measures based on alternative conceptual framework. To pursue the former alternative, this study specifies and examines 18 gravity-type and cumulative-opportunity accessibility measures using a point-based spatial framework. For the latter option, 12 space-time accessibility measures are developed based on the construct of feasible opportunity set. This paper compares the relationships and spatial patterns of these 30 measures using network-based GIS procedures. These indices are computed using travel diary data collected in Columbus, Ohio, and a digital data set of 10,727 selected land parcels. Results of this study indicate that integral and space-time indices are distinctive types of accessibility measures whose patterns are determined by different factors. Due to the contextual and situational nature of individual accessibility, measures based on the space- time framework offer attractive alternatives for capturing the effect of personal attributes complex travel behavior and space-time constraints on personal accessibility.

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