Excellent points raised by Allen Graetz concerning the technical complexities and financial risks associated with PRT. Good bus service and higher density, mixed-use development along major transit corridors probably represents the most cost-efficient method of moving large numbers of people in Minneapolis, especially given expected improvements in hybrid technology in the near term. Such development also increases the likelihood of people being able to work right in their neighborhood, as the higher densities support increased commercial activity in the immediate area.
As higher density/mixed-use development takes place along the Hiawatha light rail route, I expect the often-questioned public investment (primarily state/federal dollars) will look much better in hindsight-- granted the right-of-way was largely sitting there for decades (similar to r-o-w in Greenway). It's also doubtful any significant state/federal support would be available for such an intra-city transit option vs. inter-city options being considered. And, as Allen points out, the city debt load is already stretched to the limit. When it comes to the city of Minneapolis funding such experiments, I'd suggest that the use of property tax dollars to subsidize such financially risky ventures is not a prudent decision. Michael Hohmann Linden Hills www.mahohmannbizplans.com ...where planning for the future pays off. '05 Candidate for 13th Ward City Council > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Behalf Of Allen > Sent: Wednesday, January 05, 2005 11:17 AM > To: [email protected] > Subject: [Mpls] PRT and Transportation > > > Buenas Dias, > snip > > As for PRT demonstration, I've given this some thought. As I posted @ 4 > weeks ago, PRT is essentially the same type of system as the new > fancy pants > baggage system installed at Denver International (DIA) in the mid > 90s. The > difference is the safety issue is that much more acute. > > The systems are essentially the same because they both involve a > single car > / cart that can start at any point on the system and can have a > destination > anywhere on the system. It's just that one carries a piece of luggage and > the other carries a person. > > I'm not sold that a demonstration system will prove anything. As > simple as > the concept of PRT is to explain, the size of it makes it very > complex. The > baggage system at DIA has been a complete flop. This despite a > mini system > having been built for United's use at SFO and a larger version of SFO's > built at the "new" airport in Munich. The issue for a system like that is > that something that is 10 times bigger is NOT ten times more > complex. It's > likely thousands of times more complex. > > If I've got the concept right, the complexity can be seen by the number of > stops on the system. The number of possible routes that can be taken from > stop A to stop B, stop C to Stop A, et al. So the number of > possible routes > is (n-1) + (n-2) + (n-3) + ... (n-(n-1)) where n is the number of > stops on a > system. So 7 stops gives 28 possible routes for the computer to > handle FOR > EACH CAR. Note that since a system is going to be running more than one > car. A system with 17 stops gives 153 route possibilities for > each car. 40 > stops gives 820 routes; 100 stops yields, 5,050 routes; 250 stops gives > 31,375 route possibilities. I think you can see how quickly the > complexity > of the system grows. And as the system adds more stops, one would assume > they're adding more cars. > > I don't know the number of nodes on the system at DIA. That > baggage system > had to serve 89 gates. Surely there were origination points in > the terminal > for every couple of ticket counters so I'll assume 25. There are 24 > curbside baggage stations. I would assume another 27. That ultra crude > estimate would make for 165 nodes. At peak usage, it had 3,550 > cars in use > on that system. So each of the 3,550 cars has @14,000 route > possibilities. > > > In comparison, if the city of Minneapolis were to implement PRT > for the city > with a stop every 1/3 mile, it would take about 350 stops to serve the > entire city. Or to put it another way, it have about twice the number of > nodes as DIA (keep in mind my estimates were crude for DIA). But that > yields nearly 62,000 route possibility for each car. And how > many PRT cars > would be running on the system at any one time? It took 3,500 for DIA's > system which had half the nodes and would be considerably than > half in terms > of track milage to cover. > snip > > You may say that's unfair to assume that the entire city would be covered. > They're likely to role it out in smaller portions. But to not cover the > entire city would defeat the purpose of PRT. It's advantage over > traditional mass transit is that it can deliver people nearly doorstop to > doorstop without a transfer. To do this, a PRT system has to > quickly cover > major parts of the city. It looses effectiveness once it becomes merely > another cog in the transportation machine. > > I hope this helps to give some sort of ball park idea on how truly complex > building a PRT system would be. And the thing is, DIA's baggage > system is a > flop. It failed. United Airlines is on the verge of abandoning it. DIA > had to sell it to United because other airlines refused to use > it. And the > city of Denver to this date, 8 years after the airport opening, still owes > $300 million just for the cost of the baggage systems at DIA. > snip > Why should the taxpayers take on such a risk? If telecommuting becomes > socially acceptable we could see a huge drop in traffic. And at > that other > congestion issues could be solved in the next 10 - 20 years if cars can > "drive themselves". The latter is just starting with some > vehicles already > able to avoid crashes while cruise control is set. And the former, > telecommuting, nearly has the technology in place to make it cheap and > practical. Throw in emission reductions via hybrid vehicles and, further > off, fuel cells and it's likely that we're nearly at the peak of the > personal transportation problem. When we have a city that still needs to > pay down it's existing debts that consume something like 12% of the annual > budget, why take on this huge risk? > > Allen Graetz > Lowry Hill > snip REMINDERS: 1. Think a member has violated the rules? Email the list manager at [EMAIL PROTECTED] before continuing it on the list. 2. Don't feed the troll! Ignore obvious flame-bait. For state and national discussions see: http://e-democracy.org/discuss.html For external forums, see: http://e-democracy.org/mninteract ________________________________ Minneapolis Issues Forum - A City-focused Civic Discussion - Mn E-Democracy Post messages to: mailto:[email protected] Subscribe, Un-subscribe, etc. at: http://e-democracy.org/mpls
