I was walking to school, about half a mile or so, when I was around eight, possibly earlier; I can certainly remember walking to school in the heavy snow in 1963, I was the first boy at my school to wear long trousers because it was so cold, started snowing Boxing Day, snow melted end of March, my brother was born at home that January.
Traffic was different then, though, hardly anyone owned cars, and the town had around 19,000 people, it’s up around 55,000 now.
Would I have a problem nowadays? It would depend on circumstances and location, there are several schools very close by, so from around seven, yes, I’d be quite happy, if the child was happy to do so, and was aware of possible risks; there is a busy road which is just a few yards away, and which a child would have to cross, but there are two pedestrian crossings, and other kids around.
It’s doing a proper, intelligent risk assessment, innit.