This study used an ecological framework to examine individual, social and environmental factors associated with cycling to school, stratified by gender and is one of the first to consider cycling independent of other forms of active transport. Urban features such as distance, traffic exposure and pedestrian connectivity were associated with cycling behavior in boys, however in girls, parental perceptions of the environment appeared more important. These results support other evidence within the AST literature that distance and parental concerns about traffic safety are associated with AST [20, 25–27] and emphasize the importance of proximate school catchment areas with highly connected streets and low traffic volumes to encourage cycling to school [28, 29].
Environmental perceptions regarding neighborhood safety issues (i.e., whether the neighborhood is safe enough and the need to cross busy roads) were associated with cycling in boys and girls. Safety is a common correlate of AST [11, 13, 16, 27]. Kerr and colleagues  found that children whose parents had few safety concerns were up to five times more likely to use AST compared with parents who had more concern . However, they argue that a simple interpretation of this association, that parental education could increase children's active transport, should be resisted because parental concerns were related to real safety issues such as poor walking and cycling facilities and traffic danger. Interventions that attempt to change parental perceptions without considering the commuting environment may be less effective. Approaches such as the Safe Routes to School interventions that aim to improve safety through planning and design  in combination with promotion activities  hold most promise.
This study found that parental confidence in their child's ability to cycle to school mediated the association between perceived safety and cycling. This highlights that in addition to modifying the environment to make it safer, skill development may also be an important strategy to help alleviate parental concerns about safety and increase cycling. Cycling accidents are among the most common causes of physical injury to children , and a number of studies have found that untrained  or less cycling-proficient children  have much higher accident rates than other children, even though they may cycle less frequently. Thus, educational programs that develop children's motor development, such as pedaling, balancing, steering, and braking as well as cognitive elements such as concentration, attention, judgment, planning, decision making and overall confidence are likely to be important . Moreover, education of the road rules, wearing the right protective gear and bicycle maintenance are other important skills needed to make children's journey to school safer  and increase parent's confidence in their child's ability to negotiate their environment.
This study also found that if parents perceived driving their child to school was more convenient, the likelihood of cycling in both boys and girls was significantly decreased. Indeed, previous AST research has found that parents are more likely to perceive car travel as more convenient than walking or cycling . Lorenc and colleagues suggest that parents' emphasis on the convenience of car travel may relate to cultural influences, e.g. the perception that walking and cycling are associated with low social status . It may also be a reflection of private cars becoming the solution for busy time-poor households fulfilling scheduling commitments by linking school travel with other activities. Clearly, strategies to combat this aspect of children's increasing car travel are probably the most challenging as they are very much dependent upon the individual household's structure, decision-making and lifestyle choices. Nevertheless, behavior change programs are likely to be more successful if they are undertaken in conjunction with environmental interventions to make walking and cycling more convenient. For example, Morris and colleagues suggest co-locating schools with facilities where afterschool activities are conducted (e.g., community centers and sporting fields) may assist in providing children with the option of walking or cycling while at the same time reducing the demands on parents' time .
The cross-sectional design, lack of information on non-respondents and limited range of objective environmental variables assessed in the study are limitations. The school-specific walkability index was not based on cyclability and it is possible the environmental correlates may be stronger if explicit environmental measures of the presence and quality of cycling infrastructure were measured. Distance to school may not be accurate because potential 'access' points generated around each school boundary may not reflect true access points, the shortest route may not be the route actually taken  and digitization of the informal pedestrian network may have missed some potential cut-throughs and paths through parks. Since few studies have specifically examined cycling to school, most survey items were newly developed or modified from existing items regarding walking to school. However, we did undertake test-retest reliability and internal reliability testing. Furthermore, other approaches to the analysis of this study could have been undertaken. For example, analyses could have been stratified by proximity to school which may have provided further insights into the differences in correlates of cycling to school and an alternative modeling strategy based on theoretical significance rather than statistical significance could have been adopted. Future studies might also like to use more advanced statistical methods (e.g. structural equation modeling) to explore other mediation pathways. Despite these limitations, the study included a relatively large sample, used an ecological approach, included a combination of objective and perceived measures of the environment and stratified the analysis by gender.