Getting your kids to school: Why so few walking?

Oh the stories Grandpa can tell about cutting across fields and hiking through snowdrifts in the bitter cold for miles and miles every morning just to get to school. The dedication to learning is astounding.

Or that's just the way it was back then! And they didn't have other choices for getting there. Nowadays, though, it's a whole other story. Our nation's children rarely walk to school anymore, with reasons varying from time, convenience, and safety, but seeing as how kids are fatter than ever something here isn't working. I'm not a huge fan of children walking to school alone (there are more predators out there it seems than ever before) but what about parents walking with their kids to school? Or biking? Or any other number of healthier options?

What do you think: is getting to and from school a missed opportunity for physical activity and exercise, or do kids just need to eat healthier and be active in other areas of their lives and get to school in whatever way is most convenient?