Evaluation of a walking school bus program: a cluster randomized controlled trial.

Background: The purpose of this study was to investigate the effects of a walking school bus intervention on children's active commuting to school.

Methods: We conducted a randomized controlled trial (RCT) in Houston, Texas (Year 1) and Seattle, Washington (Years 2-4) from 2012 to 2016. The study had a two-arm, cluster randomized design comparing the intervention (walking school bus and education materials) to the control (education materials) over one school year October/November - May/June). Twenty-two schools that served lower income families participated. Outcomes included percentage of days students' active commuting to school (primary, measured via survey) and moderate-to-vigorous physical activity (MVPA, measured via accelerometry). Follow-up took place in May or June. We used linear mixed-effects models to estimate the association between the intervention and outcomes of interest.

Results: Total sample was 418 students [M_age=9.2 (SD = 0.9) years; 46% female], 197 (47%) in the intervention group. The intervention group showed a significant increase compared with the control group over time in percentage of days active commuting (β = 9.04; 95% CI: 1.10, 16.98; p = 0.015) and MVPA minutes/day (β = 4.31; 95% CI: 0.70, 7.91; p = 0.02).

Conclusions: These findings support implementation of walking school bus programs that are inclusive of school-age children from lower income families to support active commuting to school and improve physical activity.

Trail registration: This RCT is registered at clinicaltrials.gov (NCT01626807).