If you’ve read any other stuff on Maddox’s site, you’ll know the kind of stuff I’m talking about. Anyways, this particular article isn’t too bad, but some of the other stuff on there might be questionable, so keep that in mind if you’re browsing around looking at his other stuff.
problem with the 3 and 4 wheel machines is they are not dynamically stable - that is, they are not stable when moving - if you try to stop fast, or take off fast you get to kiss the concrete or smell the asphalt.
the Segway can stop very quickly, keeping machine AND rider balanced at the same time.