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Santa Cruz CA USA
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I especially liked this episode. Olaf/Barrington really showed his quality. When he actually is as old as a "grandpa," he's going to be very cool. :-) What a wonderful show this is!
I'm a little confused. I thought one of the selling points of PRT was that vehicles would in fact queue up, and wait for passengers at system access points. How is this now a flaw? In Mr. Guala's letter above, his explanation for non-optimal PRT operation included the phrase "we could not modify the layout of the streets," and I think this will also be a problem faced by self-driving vehicles, which must travel along established street routes and contend with street traffic, much of which will be human-controlled and so, more potentially chaotic. People who want to take advantage of the existing roadway infrastructure must also put up with its disadvantages, one of those being that modifying or extending it is much more expensive than doing the same for an elevated PRT guideway. The "rubber hits the road," as they say, when you want to build out or provide alternative or detour routes within an existing system. Conventional, earth-bound roadway construction is prohibitively expensive to allow much of that. But new elevated guideway can be installed to serve new territory, or to provide detour routes around stretches that are undergoing maintenance and repair, much more quickly and inexpensively than traditional roadway. Because the PRT guideway is separate from the roadway infrastructure, the PRT system operators would have much greater control over its layout than they would over the layout of the streets. It seems to me that PRT can work, but perhaps can only work, if system access points (stations) are as ubiquitous as advertised (about 1/2 mile in any direction along the guideway); I do not get the sense that Masdar City access points were as numerous, and perhaps Mr. Guala can enlighten us on this point. Information about system capacity and congestion at access points, or via an app, might help passengers to route themselves to points of entry and points of exit that are least congested among those nearest to their intended points A and B. One of the virtues of PRT is the dispersion of demand, and the choice afforded passengers to modify their trips slightly to (greatly?) reduce net personal inconvenience. Finally, the desirability of shifting between personal service and GRT has been known for decades. That is exactly how the Morgantown PRT handles peak congestion challenges at the University of West Virginia. There, we would certainly expect such an approach to be necessary and effective, as the number of stations is small (5, vs. the 10 or 15 expected in an "optimal" PRT arrangement) and the population to be served is large and often concentrated at only a few locations. Still, as Mr. Guala observed about Masdar City, the adaptation works, allowing even a non-optimally designed PRT system to serve passengers successfully.
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Aug 11, 2011