Miniaturization. Complexity. Arcosanti:
http://www.arcosanti.org/media/publication/hyperBuilding.html

-About 3% of America is covered over in residential urnbanisation – hence, vast room for low-density expansion. The American population can be stabilised by reducing net immigration.
-ULTra PRT is being installed in Heathrow airport right now – low costs are confirmed with full-scale prototypes.
-At-grade ULTra applications are extremely cheap, and have enormous potential for new “eco” property developments.
-PRT systems, such as ULTra, can be platooned (vehicles operate very close, like a train) – eliminating capacity concerns.
-Electric cars can be built to be as much as 4x more energy-efficient than public transport (at an extreme).
-Contrary to incessant propaganda, modern cars, on avererage, are as energy-efficent as buses and trains (trains are terribly over-rated).
-Sprawl does not create congestion iin itself – population-growth does. Sprawl helps to keep the progressive development of congestion under control by helping to localise new travel-demand to the city fringes.
-The missmatch between modern origon-to-destination travel-demand and public tranport (linehaul) is diabolical.
-The far-reaching growth-potential with linehaul systems is hopelessly limited – for the most part, they can only support CBDs.
-High-density cities are not more energy-efficient in terms of transport. Though distances covered are less in high-density cities, high-density cities suffer from worse congestion and therefore create inefficient stop-and-go travel (eg. New York). This is a fact (though sadly never advertised).
-Private, fast, convenient on-demand travel is inherently more attractive to the consumer – and this fact has nothing to do with “habits”.
-The future will be ULTra developing, over time, into a fully automated transportation network that also operates on roads.
-Future property development will be low-density ultra-efficient true garden cities (with very little roading, due to the use of the at-grade PRT format) that promote intensive replantation.
-Communites based on forced-associations are often “polite”, but are not real.
-Cars provide “private” communities, which is what everyone really wants – that is, both privacy and good social access (to friends, family and kinky sex-partners that they meet online etc.).
-There is nothing wrong with “individualism” so long as the individual respects others and plays fair on a give-and-take basis.
-There is much wrong with telling people how to live their lives (not to suggest you’ve done that – just making a point).
-With modern technology we can have our cake and eat it too.
-The truth will prevail – in time!

I think that the amount of land and resources (not considering fuels) that we devote to personal autos is unfortunate, and PRT has the potential of freeing up some of those resources, especially the land, as well as making our streets safer.

I add, however, that if everyone switched to electric cars, we would be most of the way to a “climate neutral” world, insofar as personal transportation were concerned. An electric car that gets its electrons from hydro-, wind-, solar- or other sources that do not involve greenhouse gas emissions is not part of the problem. Even if the electrons come from greenhouse gas emitting sources, I have seen analyses which show that, even taking the losses of electricity transmission and battery charging into account, an EV still gets more miles from a unit of fossil fuel than does a combustion engine designed to burn that fuel in a personal vehicle.

Other than “increasing emissions,” how does “sprawl” defeat the goal of a “climate neutral” world? People need their space. Living in too close proximity to others (or having to work or travel in crowded circumstances) causes stress, anxiety, and conflict. I’m all for reducing the need to travel, but am not sure that greatly increasing population densities is the way to do it. It makes sense to me to reduce the need for long-haul commuting where we can, to reduce the emissions involved in such commuting — or in local travel, for that matter — where we can, and to reduce the amount of land necessary to support personal vehicles where we can. I’d also like to see any society that wishes it be able to break free of petroleum dependence. I think PRT can help us achieve most of those goals, which is one reason I support at least the continued examination and exploration of the idea.

One thing you should bear in mind is that the climate has always changed and will always change. Even if there were no humans, the climate would eventually turn nasty for some organisms and friendly to others. It happened long before we arrived and will continue long after we are gone. So the real question of concern to us is how to maximize our own happiness and ability to thrive with minimum disruption of ongoing natural processes. Also, how to adapt to the inevitable consequences of those natural processes when we must, and not delude ourselves into thinking that we are modifying or hastening them, much less that changing our behavior can disturb well-established trends in climate change.

http://innovative-transit.blogspot.com/2007/04/see-how-nothing-he-writes-can-be.html

PRT is really a hoax… a stalking horse to spread disinformation about LRT and commuter rail.

Does anybody really think that people (real people, not the digital mannequins that inhabit the computer-generated simulations on PRT websites) would cut down half the trees on their block for an elevated structure with a clear view into their bedroom window?

PRT is an infeasible transportation concept that has a 30-year record of controversy and failure.
The biggest supporters of PRT are the usual anti-rail transit suspects (MN Congresswoman Michele Bachmann, MN Representative Mark Olson, CETA member Emory Bundy…Google those with PRT and see what you get).

Here’s a You Tube video about the PRT fiasco in Minnesota: