These days, in Queensland, it's illegal for children under 12 to walk to school on their own. (Although, for better or worse, both the letter of the law and its enforcement are unclear.)
Yes, I remember when that law was introduced. I vaguely remember that it was in response to a child being murdered after being picked up while waiting for a bus.
It's certainly a different world now. But I have a 10-year-old, and he goes to the shops around the corner to buy milk and/or bread. There'd be no way I could trust him to make public transport decisions at this stage though. Maybe a year or two more.
http://www.abc.net.au/news/2017-03-09/how-long-is-too-long-t...