I'm surprised at the profound lack of understanding and foresight I'm seeing in this supposedly advanced crowd. Several inventions and discoveries were relatively unimportant at first onset; Kamen's device will be good, intiially, just for use in commercial applications (mail carriers, etc). In the future, however, there is no telling what impacts it will have. Rather than judging it based on the invention itself, try to think of it on the principles it involves and has introduced for further use in applications.
All inventions are a stepping stone for further use and application. Kamen has never stated that this machine will replace cars; rather, he believes that it will help revolutionize the structure of our cities. For those of you who aren't entirely American-centric, I think you understand what he means - ranging from the fußßgangerzone's in German cities to the structure of other cities, the impact that IT will have is, as of yet, indeterminable; I expect it, though, to be rather high. If Kamen were offering public stock, I'd be buying. From the merit of his past inventions alone, I can have faith, regardless of whether IT can be riced up. 🙂
Rob