I walk my kids to school in the US, but I definitely see kids as young as 6 walking without a parent. I choose to walk with my kids because I enjoy it, and it's easy exercise.

That said, a lot of parents still drive their kids - the vast majority I would say. Even people who live within walking distance. It definitely is faster if you look at it in a vacuum: you save 10 minutes round trip!

And when casually discussing things with them, that's usually the excuse - they just don't have the time! They're always running late! etc. But I get a 20 minute walk out of it, and spend time with the kids talking about stuff. So to that I say: I'm multi-tasking.

Part of me thinks this problem isn't much different from the fear of child abduction: overblown. But there is something especially frustrating about the times this happens because people think they are doing something good when they really aren't.