Spatial transferability assessment of a composite walkability index: The Pedestrian Index of the Environment (PIE)

Abstract

This paper analyzes the transferability of a composite walkability index, the Pedestrian Index of the Environment (PIE), to the Greater Montréal Area (GMA). The PIE was developed in Portland, Oregon, and is based on proprietary data. It combines six urban form variables into a score ranging from 20 to 100. The measure introduces several methodological refinements which have not been applied concurrently in previous efforts: a wide coverage of the different dimensions of the urban form, together with the use of a distance-based decay function and modelling-based weighing of the variables. This measure is applied to the GMA using local data in order to evaluate the feasibility of its transfer (the possibility of locally replicating the measure). It is then included in a series of mode choice models to assess its transferability (the capacity of the measure to describe walkability and predict mode choice in another urban area). The models, segmented by trip distance or trip purpose, are estimated and validated against observed trip data from the 2013 Origin-Destination survey. Significant positive correlation is found between the PIE and the choice of walking for short trips, for all purposes as well as for four specific trip purposes. The inclusion of the PIE also improves the accuracy of the modelling process as well as the prediction of the choice of walking for short trips. The PIE can therefore be used in the GMA, and potentially in other metropolitan areas, to improve the modelling of travel behavior for short trips.

A Reliability Check of Walkability Indices in Seoul, Korea

“…Thus far, approximately 80 or more walkability indices have been used [29], and it is very important to choose an appropriate index to measure the walkability level of a specific area. Many studies have attempted to determine how urban forms affect walking, and these variables have been grouped into five categories, which are collectively referred to as the five Ds (density, diversity, design, destination accessibility, and distance to transit) [30].One study suggested eight walkability indices that correlate with active transport: Walkability index (WI), walk score (WS), walk opportunity index (WOI), pedshed (Ps), extended walkability index (EWI), movability index (MI), neighborhood destination accessibility index (NDAI), and pedestrian index of the environment (PIE) [31]. These eight indices have different components, but some are similar.…”

“…It is notably difficult to choose which of these is the most effective index to use. In recent walkability studies, WI, WS, Ps, and MI have been used often [5,26,[31][32][33]. These four indices also relate to active transport behavior as well as the five Ds.The WI was developed by Frank et al [34] and is the most popular measure in urban planning and active living literature [5,35].…”

“…It is based on a measure of access to nine types of destinations (e.g., grocery, coffee shop, restaurant, etc.). Pedshed is a commonly used index to represent accessibility and measures the area accessible through the street network as a percentage of the area [26,31]. The MI is developed on the basis of the existing WI but is intended to include movability in the WI.…”

“…One study suggested eight walkability indices that correlate with active transport: Walkability index (WI), walk score (WS), walk opportunity index (WOI), pedshed (Ps), extended walkability index (EWI), movability index (MI), neighborhood destination accessibility index (NDAI), and pedestrian index of the environment (PIE) [31]. These eight indices have different components, but some are similar.…”

“…It is notably difficult to choose which of these is the most effective index to use. In recent walkability studies, WI, WS, Ps, and MI have been used often [5,26,[31][32][33]. These four indices also relate to active transport behavior as well as the five Ds.…”