Background and Purpose
The growing attention on walking to school (WTS), particularly in developed countries, is grounded in the recognition of the importance of physical activity among children who are adopting increasingly sedentary lifestyles [1].  Physical activity has both a positive, direct effect on children’s health and an indirect effect through its role in healthy weight maintenance or weight loss among the overweight [2].  The effect of physical activity on adiposity makes it an essential component in combating the childhood obesity epidemic, and recent studies have documented a positive relationship between WTS and other forms of physical activity [3, 4].

Despite its potential health benefits, rates of WTS have plummeted over the last four decades in the U.S. [5]. Several reasons for this sharp drop have been identified. Two of the most frequently reported barriers to WTS are long distance [6] and safety concerns [7]. Addressing the distance barrier is an important but difficult one, as it requires multi-faceted environmental interventions involving policy changes in land use, school siting, attendance zone, etc. [8]. On the other hand, more readily implementable environmental changes have the potential to address the safety barriers that are related to WTS. While safety concerns are hypothesized barriers to WTS, current research offers little in terms of exploring/explaining the mechanisms through which safety concerns might impact WTS [9].  Therefore, there is need for more focused empirical inquiries into the relationship between these two phenomena.

Objectives
To contribute to the growing yet limited body of literature on safety and WTS, we examined the relationships between WTS and specific measures of road safety (traffic- or pedestrian-related safety concerns) and personal safety (crime-related safety concerns) in a sample of schoolchildren selected from elementary schools across the state of Texas in the U.S. We assessed the associations across multiple environments (home, en-route and school environments) in the home-to-school journey. We also examined the relationships between selected covariates and WTS.

Methods
This cross-sectional analysis examined data from the Texas Childhood Obesity Prevention Policy Evaluation (T-COPPE) project, an evaluation of state-wide obesity prevention policy interventions. All study data were from the survey (n=827) of parents with 4th grade students attending 81 elementary schools across the state of Texas, and living within two miles from their children's schools. Using established and validated survey items, traffic safety and personal safety concerns were captured separately for the three spatial domains: (1) home, (2) en-route to school, and (3) school environments. Parents reported the mode of transportation to and from the school for their children, and answered questions on other potential covariates. Data analysis involved three steps. First, we assessed the relationships between potential covariates and WTS using chi-square tests. Secondly, we examined the relationship between each safety concern variable and WTS, using logistic regression models that produced unadjusted odds ratios. Thirdly, a series of multivariable regression models, controlling for the selected covariates, were performed to examine the association between each safety concern and WTS, independent of the influence of the covariates. All regression results were organized separately into the three spatial domains.

Results
Overall, 18% of parents reported that their child walked to school on most days of the week. For traffic safety, students were more likely to walk to school if their parent reported favorable perceptions about the following items in the home environment: higher sidewalk availability, well-maintained sidewalks and safe road crossings. For the en-route to school environment, the odds of WTS were higher for those who reported "no problem" with each one of the following: traffic speed, amount of traffic, sidewalks/pathways, intersection/crossing safety, and crossing guards, when compared to those that reported "always a problem". For personal safety in the en-route to school environment, the odds of WTS were lower when parents reported concerns about stray or dangerous animals, and availability of others with whom to walk. For the school environment, two traffic-safety variables including sidewalk availability and trees along streets near school were positively associated with WTS, and none of the crime-safety variables were significant.

Conclusions
Findings offered insights into the specific issues that drive safety concerns for elementary school children’s WTS behaviors. The observed associations between more favorable perceptions of safety and WTS provide further justification for practical intervention strategies (e.g., sidewalks, traffic calming devices, crossing guards, stray animal controls) to reduce WTS barriers that can potentially bring long-term physical activity and health benefits to school-aged children.

Implications for Practice and Policy
Public health practitioners, other professionals, and policymakers can: advocate for more sidewalks and traffic calming devices through Safe Routes to School programs, working with neighborhood associations and city government; advocate for additional transportation funds to be dedicated to bike lanes, sidewalks and other environmental changes that encourage bicycling and walking to school; educate school area residents about proper handling of their pets outdoor; and encourage schools to help parents identify safe walking/bicycling routes to and from school.

References

1. Nelson MC, Neumark-Stzainer D, Hannan PJ, Sirard JR, Story M: Longitudinal and secular trends in physical activity and sedentary behavior during adolescence. Pediatrics 2006, 118:e1627-e1634.
2. Janssen I, LeBlanc AG: Systematic review of the health benefits of physical activity and fitness in school-aged children and youth. International Journal of Behavioral Nutrition and Physical Activity 2010, 7:40.
3. Southward EF, Page AS, Wheeler BW, Cooper AR: Contribution of the School Journey to Daily Physical Activity in Children Aged 11–12 Years. American journal of preventive medicine 2012, 43:201-204.
4. Dollman J, Lewis NR: Active transport to school as part of a broader habit of walking and cycling among South Australian youth. Pediatric exercise science 2007, 19:436.
5. McDonald NC, Brown AL, Marchetti LM, Pedroso MS: US School Travel, 2009:: An Assessment of Trends. American journal of preventive medicine 2011, 41:146-151.
6. McDonald NC: Children's mode choice for the school trip: the role of distance and school location in walking to school. Transportation 2008, 35:23-35.
7. Alton D, Adab P, Roberts L, Barrett T: Relationship between walking levels and perceptions of the local neighbourhood environment. Archives of disease in childhood 2007, 92:29-33.
8. Lee C, Zhu X, Yoon J, Varni JW: Beyond Distance: Children’s School Travel Mode Choice. Annals of Behavioral Medicine 2013, 45:55-67.
9. Davison KK, Werder JL, Lawson CT: Peer Reviewed: Children's Active Commuting to School: Current Knowledge and Future Directions. Preventing chronic disease 2008, 5.

Support / Funding Source
This study was funded by the Robert Wood Johnson Foundation (Grant ID: 64635) and contributions from The Michael and Susan Dell Foundation, The University of Texas School of Public Health, the Texas A&M Health Science Center (TAMHSC).