Mapping walkability. A subjective value theory approach

Abstract

The analysis of urban walkability has been extensively explored in the last decades. Despite this growing attention, there is a lack of studies attentive on how citizens' values, individual abilities and urban environment favour or hinder the propensity to walk. Hence, there is a need to explore how preferences and values of citizens vary in space in order to design walkability policies able to improve the capability set of citizens. In this perspective, the design of spatial decision tools aimed to plann public policies for the development of walkable cities needs further investigation. We propose a Multiple Criteria Decision Analysis (MCDA) method aimed to elaborate walkability decision maps for different groups of citizens that reflect their capability to walk in the urban environment. We tested the method in the city of Alghero (Italy). First, we analysed walkability under a normative model named CAWS; then we made a survey with 358 participants in order to study the driving values that influence their choice to walk and finalised to build an evaluation model attentive to individual differences. Cluster analysis was employed to group citizens into 11 groups based on their sociodemographic characteristics and preferences on spatial criteria of walkability. Finally, by integrating GIS with MCDA we built a set of decision maps representative of the walkability of the 11 groups of citizens. Results highlight the importance of citizens’ values for policy design, allow the interpersonal comparison among individuals and group preferences and give new suggestions for the formulation of walkability oriented urban policies. Moreover, the results confirm the usability of the general method as a decision support tool supporting the design of urban policies.