Children are encouraged to walk to school, to give them an opportunity for more exercise and to create less congestion and pollution around schools, but there are barriers to overcome, as outlined in this Slate article:

In South Jordan, Utah, a woman was cited with child neglect for allowing her son to walk to school. Why was he walking? Because the school had eliminated its “hazardous bus routes.” What’s a hazardous bus route? A bus route meant to pick up kids who live in areas without sidewalks. There is child neglect going on here, for sure, but it’s the neglect of a system in which children within walking distance of school cannot actually do so.

It is easy to hold conflicting values without realizing it.  Of course we want parents to look after the welfare of their children, but what does that mean in practice?  Is there a way to look after both their safety and their health?  What about a walking school bus?