On September 24, much of the world was thrilled to hear Pope
Frances tell the USA to think globally about the impacts of its greed and wars.
The PRT world was also buzzed by a NPR (National Public Radio) report on PRT possibilities
with an impressive interview with Mike Lester of Taxi 2000.
Explaining PRT and its potential benefits to the general public
will no doubt start many productive conversations from coast to coast and overseas
as well. The balanced conclusion of reporter Joe Palca’s story held up a countering
view from a Minnesota official: PRT is an idea whose time has come and, with
smart cars in smart cities, gone. The main culprit is the cost and offensiveness
of elevated guideways, intersections and station.
Elevated, Shmelevated
Elevated guideways were highlighted upfront by Lester as a
major plus. They free vehicle movements from the clutter and danger of street
traffic. They overcome the friction of space. Passengers ride faster and safer.
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However, the onset of automated road vehicles is creating
new solutions. Much of the promise of PRT is that it satisfies local
circulation and connection needs. Future next-gen roborcars will be able to do
this without exclusive guideways.
Fixed infrastructure makes up about 70% of PRT capital --
even with elevated guideways that are cheap compared to LRT. So removing them from a mobility service plan
is a big thing. It changes the business model dramatically.
For longer trips, exclusive guideways are needed, but PRT
must walk before it runs. Ten- or twenty-station networks were considered within
technological reach by MTI’s study team last year. Why? Because Vectus in Suncheon and 2getthere
in Masdar both have only two stations -- not networks at all, let alone complex
ones. Ultra at Heathrow has three. Morgantown has five -- where on-demand
scheduling and fleet management start to get a little complex.
The problems, costs and non-financial “externalities” (violations
of privacy, noise, droppings, shade, blockage of views, etc.) of elevated
guideways are real. PRT promoters do themselves a disfavor to minimize or
ignore them.
Think 3D
Presenting PRT infrastructure as elevated and only elevated ignores the fact that Masdar isn’t elevated at all. Parts of Heathrow and Morgantown are at grade.
Most metros and older LRTs move up and down in 3D reality - with underground,
at grade and elevated sections.
PRT is no different. Certainly it can and in many places
should be elevated, but it can be even cheaper at grade - enhanced by bunker-like
earthwork, plantings and smarter and smarter security systems. In pretty
neighborhoods where real people live and shop and walk and where buildings are
close together, the expense of tunneling may be quite justified.
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| Guideways have vertical dimensionality. |
In the end, the future of PRT will not be decided by the
optimality of the gadgetbahn, but by the sensitivities and lifestyle
preferences of three-dimensional neighbors and lawyers.
