Exploring the trend of walkability measures by applying hierarchical clustering technique

Abstract Introduction Over the last two decades, many walkability attributes and variables have been considered in the evaluation of walkability scores with various methods and approaches. This study investigates the recent trend of walkability measures in terms of the scale of analysis, the case study location, the type of measurements, the data collection tool, the analysis method, and the research field. Methods In a review of existing literature, this paper analyzes and compares the walkability studies over the past two decades. A total of 75 articles from 40 journals and conference proceedings were selected through a systematic and sequential procedure. In order to explore the research trend among the reviewed articles, we applied a hierarchical clustering technique. A meta-analysis was performed to systematically assess the results of previous walkability studies to derive conclusions about the future direction of research. Results The result of this review reveals that recent walkability studies in North America have prevailed in a street-level microscopic analysis while the others in Asia and Europe have focused on both large and small-scale walkability analysis. Advanced images and instrument audit tools are being applied nowadays in addition to traditional physical audit tools for measuring walkability. In recent years, urban design qualities objectively measuring at a street level (e.g., comfort/convenience, aesthetics, sidewalk design, etc.) have been widely used in determining walkability in lieu of the traditionally used attributes (e.g., roadway level of service). Conclusion This study presents a future direction for walkability studies along with the recent trend in walkability measures and data analysis. Walkability studies have attracted significant attention more recently than in previous years. The recent trend of automated and systematic walkability data collection will eventually enable detailed analysis at a large scale and contribute to advancing walkability studies.