Shes uses bus and train but generally there are plenty of other people about if anything happens.
In a taxi though if anything went wrong or the driver decided to take advantage in any way she would be in a very vunerable position. My friend laughed and said I was being over protective and she lets her 11 year old dd use them all the time. I know that the majority of drivers are decent hard working people but somehow.can not shake off the worry she might get one who isn't.. probably because when I was 18 O was faced woth a driver who doubled usual fare and when I couldnt pay got in the back and tried to grope me... I managed to whack him in face get out and scream and man passing by stopped and stayed with me but I cant get it out of my head 20 years later