According to this Time magazine article, ...
here's the link, the pivoting action is envoked by a hand grip. According to those who've ridden one, it's very intuitive. Even known skeptic Andy Grove of Intel said he learned how to ride one in only 5 minutes. Like I said, I don't see myself buying one but they could possibly be popular as rental vehicles in tourist areas. If you go to the Time article, be sure to look at the interactive link on the top of the first page.