• Since 1970, obesity prevalence more than quadrupled in ages six to eleven. There are several pleas for research that would concurrently evaluate the threefold relationship between the built environment, children’s physical activity levels and impact on obesity. Having to pay for physical activity either monetarily or in lost leisure time is a recent phenomenon in society. Many people will not or cannot sacrifice time or money in order to purposely exercise, although society benefits with opportunities for physical activity within normal daily routines. For children, a normal daily routine is the trip to and from school.
• This study employed a quasi-experimental design of five Oklahoma schools with a Walking School Bus during school year 2009-2010. The study measured pre- and post-BMI in 1102 active commuters and controls ages five to twelve. A parent questionnaire evaluated dose response, confounders, and contributors or barriers to a child’s active commute.
• The provision of a chaperoned walk-to-school program in areas with lower walkability increased the percentage of children actively commuting to school to 39.8 percent, as compared to the national average of five to fourteen percent, p < 0.0005 (one-tailed)( SPSS Nonparametric Binomial), and decreased BMI, z = - 10.125, p < 0.0005 (two-tailed)( Wilcoxon Signed Rank). Sixty-six percent of obese students that actively commuted to school were no longer obese in post-testing. Forty-seven percent of overweight students that actively commuted to school were within the healthy weight category in post-testing. The number needed to treat was thirteen indicating that one case of obesity or overweight was prevented when thirteen students actively commuted to school. Walking School Bus participants walked 65% farther than students that walked without an adult chaperone.
• The provision of a chaperoned walk-to-school program was sufficient to overcome many barriers to the active commute to school such as disability, age, gender, distance and other environmental factors. The Walking School Bus significantly increased the percentage of children actively commuting to school and overweight and obesity significantly decreased in students that walked or biked to school.

Quarles, J. (2012). Walking school bus and its impact on BMI, Dissertation at the University of Oklahoma Health Sciences Center.