Really you can't generalize. It depends on the general safety of the neighborhood, how much traffic there is and whether they have to cross busy streets, whether they walk on sidewalks or on along a road, as sometimes happens in a rural area, how far away the bus stop is and how many other kids wait there, whether they can walk with a sibling or friend, and how responsible the kid himself is. My kids walked to and from school starting in second grade, a distance of about 4 blocks, but they always walked with other kids and lived in a town where they knew several people who lived on every block. The school also had a system where parents were supposed to call in early in the morning and say if their kid was not going to be in school. if a kid did not show up at school and the parent had not called in, the parent got a call from the school checking on whether the kid should be there or was really at home. The town also participated in the McGruff Safe Houses program and the kids were taught in school to go to a house with a McGruff Safe House sign if they were nervous about anything that was happening.. Most of the kids in town walked, so they rarely walked alone, and in the 15 years that we lived there, there was never a problem, but in a bigger city I would not have let my child walk alone until a much older age.