Mendoza 2009.

Methods	Design: Controlled before‐after study One intervention group and two control groups Duration of follow‐up: 1 month, 6 months and 12 months
Participants	Country: Washington (state), USA Setting: Urban primary schools Intervention group: 1 school, 347 children Control group: 2 schools, 473 (293+180) children Age: 5‐11; Gender: female 44% (intervention school), 43% and 52% (control schools) Socioeconomically disadvantaged schools
Interventions	Walking school bus (WSB) co‐ordinator for 10‐15 hours per week Designed WSB routes WSB operated 1‐2 days per week according to volunteer availability; parent volunteers recruited to run WSB Promotional material and events Pedestrian safety activities Duration of intervention: 12 months
Outcomes	Travel to school on day of survey (hands‐up survey). Survey conducted on day when WSB not operating and no other promotional event operating Effects on inequalities not reported Adverse effects not reported
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	High risk	Not randomised
Allocation concealment?	High risk	Not randomised
Blinding? All outcomes	High risk	Not feasible. Could have influenced outcomes
Incomplete outcome data addressed? All outcomes	Unclear risk	No matching of participants in baseline and follow‐up samples, so not possible to fully assess attrition. From the data provided, we estimated intervention group response rates to be 81% (baseline) and 87% (12 months), while control group response rates were 79% (baseline) and 72% (12 months)
Free of selective reporting?	Unclear risk	Not clear that all pre‐specified outcomes were included
Free of other bias?	Low risk	No other sources of bias identified
Adequate matching of intervention / control groups?	Low risk	Similar neighbourhood attributes and travel mode use at baseline