The US may be the most extreme case of this problem, but not every country has it as good as Norway either.

I'm from Spain and sadly no kid here goes to school on their own at 5 or 6. Most start at 8 or 9, and typically "experts" recommend 7 as the absolute lower bound. While not as car-centric as the US, we still have too many cars in every city (and too fast) to feel safe leaving kids alone at 5 or 6.