Active school transport (AST) - walking or bicycling from home to school at least once a week - brings the children health benefits but it also helps to develop sustainable mobility in the city. Together with building social relationships in the environment it forms one of the principles of the Smart City concept. The ultimate decision whether an eleven-year-old child will actively travel to school is definitely in the hands of the parents. AST differs from the moderate walking activity of adults. It is a very complex problem influenced by social aspects of the family and the perception of the environment. This paper searches for the most influential factors that affect if a child will perform AST or not and subsequently analyses the selected route. The pilot study took place in Radotin, Prague. The route choice is studied using the Space syntax variables - choice and integration, the urban qualities such as the presence and width of sidewalks, street maintenance or active facades along the journey. The interpretation of the environment is collected through semi-structured interviews with parents and their eleven-year-old children attending primary school in Radotin. The first outcomes indicate that parents perceive AST very positively. Children usually start to perform AST around the age of 10. Some of them are escorted to the school in the morning by their parents and use AST only for the way home. The children are very familiar with the environment. The route choice approximates to the straight direction between school and the child's home; even though it can result in a quite complicated journey. The number of turns, the number of segment and the Space syntax choice values of the selected route do not seem to overweight the directional factor that affects the route choice. The selection of the specific route can be influenced by its urban qualities. Especially, active facades with good visual street control are appreciated.