Warren's View of PRT Attributes is Too Limited


Dennis Manning

Roxanne Warren (in the previous post) rejects PRT not on the basis that it
will not accomplish what Dr. Anderson claims, but rather on the basis that
"simpler" systems can be used to develop the kind of liveable communties

that she would like to see. And she sees PRT as a further aggravation of "sprawl"


"Anderson sees PRT as a tool for making urban sprawl more workable. I see
automation in transit as a potential instrument for both curbing and
modifying sprawl, by creating, through targeted financial incentives,
distinct channels of new, higher density, but landscaped, development within
existing metropolitan areas - in order to absorb new population growth
within existing cities and suburbs, and for this purpose, far simpler
systems than PRT should be sufficient."

I think Ms. Warren prejudges on both counts. In regards to Dr. Anderson's
large PRT network, why does Ms. Warren install preconceived notions about
how suburban/urban land uses will be changed by PRT?  PRT could just as
easily constrain sprawl by restricting the limits of coverage. How it
unfolds is not inherent in PRT itself, but rather in how land use adapts.
PRT can provide new options.

Ms. Warren's statement on the second count:

"While Anderson advocates PRT as a solution for ".....vast, already-settled
(currently automobile-dependent) portions of urban areas.....", it seems
doubtful, indeed, that a sophisticated, automated guideway system could be
afforded in (conventionally planned) areas which are sufficiently
low-density to provide a truly green residential environment - or, indeed,
that in such areas, an elevated guideway carrying a publicly accessible
transit system would even be welcome."

Why is PRT constrained to elevated guideways in green residential
environments? No imagination. PRT could be at grade or partially below grade
then covered and greened - easily walked across. Why is PRT restricted to
conventionally planned areas? Plan a bit differently to make PRT
aesthetically acceptable. Why, since PRT is smaller and lighter, would PRT be
more expensive than larger APM vehicle systems?

I suspect that the constraints on PRT stem from assuming that a heavily used
PRT built along existing boulevards etc. is all that is possible in a green
residential area. Not so. In a residential area PRT could operate
effectively at lower speeds - very quiet. Less noise than larger APMs. At
the lower passenger volume requirements in residential areas, off-line
guideway could be all but eliminated by slowing vehicles on-line then
exiting off-line at very low speed. Even if elevated, in residential
settings, guideway height could be reduced to well below building heights.
PRT guideway could easily be festooned with attractive greenery.

By placing constrained (or even false) characteristics or limitations on PRT
and on accompanying land use possibilities, Ms. Warren overlooks the very
attributes that would most enable the development of the green residential
areas she desires.

For a scenario suggesting how PRT could be the enabler of "mini-cities"
read Chapter 9 of the new book - "Tomorrow's Transportation - Changing Cities,

Economies, and Lives"
by Garrison and Ward.


Last modified: September 27, 2000