I was also particularly surprised by the huge reduction in the percentage of 7 or 8 year olds who went to school on their own in the nineties versus the seventies:
Aside from wondering how the parents find the time to transport their offspring, I feel sorry for the children who miss out on their pre and post school strolls. When I was four or five, in the late seventies, I did the school journey accompanied by my slightly older siblings, the eldest being just eight. We had the luxury of a road-free journey, as our house backed onto a large park, the other end of which contained our schools. Nowadays I'd guess that parents would be worried about strangers lurking in the park...