Question on a slightly different setting: in more urban areas with public transport, is it common for kids (past some age) to be allowed to travel places on the

Question on a slightly different setting: in more urban areas with public transport, is it common for kids (past some age) to be allowed to travel places on their own on metros/buses? It's definitely common here (Copenhagen), and from what I gather also fairly common in other European cities, and in Japan. But I have no idea if it is in NYC, SF, or Chicago. I think it's partly normalized here from a certain age because we don't have school buses, and instead kids are expected to take the regular transit. So then it's not a huge stretch for them to take the same buses to piano lessons, friends' houses, etc.