What the F is wrong with Americans. Srsly.
Maybe I'm just a terrible parent, but I wouldn't trust my 5 year old to walk to her stop and get on the bus at a specific time every morning without a parent around to push her to do it.
Plus, I would argue that there is a difference between sending a kid off to school at a given time and leaving them home alone with a specific schedule of "At 8:45 you need to walk to the bus stop and wait for the bus". Which again, I'm not sure I would trust to my 5 year old to do on her own every morning. Not because she can't walk alone, but because I don't think punctuality is something she's mastered yet.
And even the article admits that young kids can do that more because of "social trust than self-reliance". And I don't know how many parents are willing to rely on other adults to help out their kid if something goes wrong.
I would wake up after my dad was gone for work, grab a pop-tart or cereal, take a ~1/4 mile walk outside to the bus stop, no longer able to see my house from the suburban sprawl, and hang out with the rest of the kids at my stop for 5-15 minutes before the bus showed up. Then I eventually got a car.
Don't get me wrong, if I was offered a ride (my parents, friends parents, friends with cars) I'd often take it. But ensuring I got on the bus? When the alternative was that my parents would get a phone call about me being missing? Trust that the lessons I'd get at school were far preferable to the lectures I'd get at home if I skipped class.