School Walkability Index: Application of Environmental Audit Tool and GIS

Introduction: Active school travel is an important way to promote children's physical activity, but it requires supportive environments that can safely and comfortably accommodate children's walking and biking. Few existing indices explicitly consider school neighborhood environmental factors related to children's walking to school. In this study, we used a street audit tool and Geographic Information System (GIS) to evaluate walkability near low-income elementary schools in Seattle, WA.

Methods: The audit-based school walkability index was developed based on all street segments (n=841) within a 0.4km network buffer from each study school (n=18). The GIS-based school walkability, a combination of road connectivity, vehicular traffic exposure, and residential density, was also measured in a 2km network buffer around each school. The participants were individuals aged 8-11 years (n=315) who participated in the Walking School Bus randomized controlled trial project. Mixed-effects logistic and linear models were used to examine the association of the index's representations of the built environment with children's school travel mode (walking or biking to school 1+ times per week) and with objectively measured moderate-to-vigorous physical activity (MVPA, average weekday minutes during the 90-min before-school period). These associations were tested with the total sample as well as the subsample of children living within 1.5km from their schools.

Results: The audit-based school walkability index (WI) was positively associated with both active commuting to school among the subsample living within 1.5km from their schools and with children's before-school MVPA among the subsample and the total sample. The GIS-based school WI showed significant associations with children's before-school MVPA but no relationships with active school travel among the subsample and the total sample.

Conclusion: The audit-based school walkability index can be used as a complementary tool for measuring walkability near low-income elementary schools along with existing GIS-based school walkability index.