Since we keep discussing school runs, I'm curious to know why it doesn't seem to be common in the UK that kids go to school on their own. I know the SJ live quite far away, but I'm talking about kids who live within like a one mile radius of the school.
Were I live (central Europe) kids start school after they turn 6. Parents usually walk with them a couple of times until the kids know the route and then they go on their own or with other school kids from their neighborhood. It's also very common to see kids as young as six taking public transport (bus, tram, train,...) to school on their own. Some also take their scooters and by the age of 10 kids are allowed to ride their bikes without adult company. It's completely normal here.
I remember when I started school at six and was allowed to walk to and from school alone, my mom wanted to surprise me and pick me up from school and I bursted out in tears when I saw her at the school gate, because I was so upset and wanted to go alone. She never dared to pick me up ever again.