In our view, it is a big waste of time advocating such "gee-whiz" options, given the severe limits of monorails and similar technologies such as PRT, when U.S. transportation problems are almost always sociopolitical and economic–not technical–in nature.
Demery returns to the subject in "Where's the Gadgetbahn?" at publictransit.us
If there is a country where Personal Rapid Transit (PRT) "should" work and "should" already have been built, then it's Japan.
Having traveled extensively throughout that country over the past three decades, I shall take this a step farther: if there is a place in Japan where PRT "should" work - and "should" already been built - then it's _____.
One could fill in the "blank" above with a number of locations, based on empirical observation of the built environment. During the past five years, maps and aerial photo images became available online and quality has been improved steadily. It is now possible to study the urban geography of Japan, "armchair" style, whether or not one has any knowledge of Japanese. This series shall present several examples of locations in Japan where the built environment appears conducive to PRT development. It shall also consider results obtained by other transport modes, e.g. automated guideway transport (AGT), in specific locations.
Excellent article - read the whole thing.