Using GIS to analyze the role of barriers and facilitators to walking in children's travel to school

Abstract

Extensive research in response to the decline of walkability in the past 30 years has identified a multitude of factors that affect children's ability to work or bicycle to school. Among others, urban form – the layout and configurations of urban blocks and street networks - can constraint or facilitate pedestrian travel to a destination such as a school. Although contemporary research uses approximate measures of walkability such as straight-line distance between origin and destination, or even measures of distances along roadway networks, the presence of physical barriers and facilitators to walking calls for a more accurate method for assessing walkability as a function of distance dictated by constraints of urban form. Modern technologies like Geographic Information Systems (GIS) offer capabilities to enable calculation of such measures. This article presents a GIS methodology that analyzes children travel to school as a function of distance along the network and the role of barriers and facilitators that impact the path and the accessibility to school. The study is conducted in 32 randomly selected elementary schools in four Florida counties. Three pedestrian sheds of 1/2 mile (10 minutes walk) are generated around each school based respectively on (a) straight-line distance, (b) roadway network distance and (c) pedestrian network distance adjusted for barriers such as major roads, and lack of sidewalks and facilitators such as pedestrian paths, crossing guards and rear entrances to school. The pedestrian sheds are compared based on two measures: (1) pedestrian route directness (PRD) – an index that measures urban form permeability and connectivity and (2) the student count in each shed – a measure that indicates how effectively the pedestrian shed captures potential students along these networks. Results show that the pedestrian shed decreases in size upon considering network distance over straight-line distance, and readjusts upon consideration of barriers and facilitators. PRD values decrease as the pedestrian shed is adjusted which indicates shorter, more direct paths to schools are available. Findings suggest that inclusion of barriers and facilitators when measuring distance along the network offers a more realistic version of the true distance a child could potentially walk to school. The study found that barriers and facilitators play critical roles in how the urban landscape can be traversed and, in turn, greatly affect walkability and accessibility to school. Barriers can reduce walkability and accessibility to school whereas facilitators can increase the permeability and connectivity of pedestrian networks. In addition to improving walkability measurement methods by enhancing the GIS network analysis to include barriers and facilitators, this research has broader implications for the study of walkability as it relates to urban form. The findings can be used by local governments to develop better policies to promote close coordination of school siting with residential development and transportation. These findings can also inform the urban design of the layout and configuration of street networks, urban blocks and placement of buildings to support safe pedestrian circulation with good permeability connectivity and accessibility throughout the neighborhood. Especially, findings from this study emphasize the importance of designing for connected pedestrian paths that minimize barriers and maximize facilitators.