'Why is travelling alone still considered a risky persuit for women?'

http://www.theguardian.com/lifeandstyle/womens-blog/2016/mar/21/travelling-alone-risky-women-sexist-attitudes

This article highlights the fact that it is still considered dangerous for women to go travelling on their own or with a small group of them and why it is acceptable to for men to travel on their own.