One of the Best Analyses of PRT You’ll Ever See

Post by Steven Dale

Image via swiftprt.com.

We here at The Gondola Project tend to be a pretty open-minded group of individuals with our readership generally following suit. We’re not, however, slaves to fads or trends. When we look at new ideas, innovations and technologies, we try our very best to be objective and analytical about them (but appreciate and love the craziness of things like the Chinese Tunnel Bus™).

We approach things from a position of empirical skepticism. We need to see that something can actually work – or at the very least, that the theory and logic underpinning a concept makes sound and reasonable sense. As a result, we’ve tended not to have a fondness for the mythologized panacea of the public transportation world; Personal Rapid Transit (check here and here for two of our more interesting debates with PRT advocates).

The fundamental logic behind PRT is quite simply flawed with most advocates of the technology blind to the economic and technological limitations of it. But that doesn’t prevent it from being continually trotted out as transportation messiah.

That’s why the work of blogger and researcher Apatzer is so fascinating.

Over at a brand new site called Swiftprt.com Apatzer meticulously (and sometimes exhaustingly) details the 6 months he spent researching and coding a simulated PRT network to investigate the technology’s feasibility.

His basic findings are that PRT is financially unfeasible; is incapable of providing the needed capacity in dense urban environments; and cannot provide the time savings over the private automobile typically sold by PRT advocates and companies.

I won’t go through his entire analysis as that would take about as long as it took him to do his study. As such, it’s hard for us to say whether his work is “right” or “wrong.” But for anyone interested in PRT as a viable urban transportation solution, they should spend a serious amount of time and energy exploring his work.

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  1. I read the swift PRT site a couple of weeks ago, and as you say it is of an excellent standard. I feel that you miss represent it in one way. In it he concludes, not that PRT is infeasible, but that the raised maglev is prohibitively expensive, largely because of the cost of steel compared to concrete/asphalt. "It is clear that a maglev based personal rapid transit elevated track system should not be pursued as a business." However I think the implication of his conclusions are that he sees self driving cars as the future. Possibly extrapolated to the extent at which they could be considered a PRT system?
  2. Giles, Your quibble is somewhat justified. At the same time, however, I'm not sure even a more "standard" PRT system would be cost-efficient enough to justify the technology. Furthermore, that doesn't eliminate the other problems Apatzer around with the technology. Funny you mention the self-driving car as PRT. We made a similar point in a previous point here.
  3. This is a really awesome site. But why does he say it "is similar in cost to ski-lift systems, where cost runs around $2 – 3m per kilometer[9]." The examples is a lift through a tunnel in a mountain http://www.snowbird.com/about/construction/peruvian.html I thought ropeway transport was one of the cheapest of options, does it equal construction cost of elevated maglev?
  4. I found that a touch odd myself. I think what he's doing is this: Because the upright structures he imagines would be similar to a ski lift (towers, bases, etc.), he reasons that to be an appropriate comparison. Furthermore, because a PRT Maglev would have dramatically slimmer infrastructure needs than a full-scale maglev system, I don't think he's making the comparison to a "elevated maglev." And did I just totally miss the fact that there's a ski lift running THROUGH a mountain in Utah?!?
  5. You present your site as being 'Open-minded". In light of this statement, could you please tell me why some responses from PRT advocates are being refused? It is easy to believe Dr Vuchic or Avidor, who have never built anything, and who say PRT lacks potential volume. It is easy to compare PRT with the cost of roads, without including the cost of cars and fuel and other costs, which gives a slanted view. Can you give us the capacity (passengers/hour) of the gondolas?
  6. Hi Jack, I'm not sure where you're going with this, but we've never refused any pro-PRT comments - so long as they're phrased respectfully and politely. But that goes for any comment. If there's a comment we somehow missed, feel free to call our attention to it. And we'll be glad to remedy the situation. As for your comment about Vuchic having never built a PRT system . . . Fair enough. But strangely the PRT industry has never built a PRT system either, so you'll forgive me if I let that one go. As for gondola capacity - up to 6-8k pphpd (depending who you ask). That number's all over this site.
  7. Apatzer made a comparison mistake regarding "track" costs : He compared the 5,6 million$ cost of Snowbird Peruvian lift : this represent the total cost that in a Gondola is made by more than 60% from the stations - if the Peruvian lift was to be double in length, the cost probabily will increase just by 10/15%. Really interesting work , however.
  8. Sorry , there are 2 recent Prt systems in exploitation! http://www.ultraglobalprt.com/performance-stats/ http://www.2getthere.eu/?p=990 Plus the WVU for 40 years! http://transportation.wvu.edu/prt In Brasil they plan a system that is a mix between gondola and prt http://www.misterbrasilprt.com.br/ I just think gondola-systems do not exclude PRT-systems! Just depends on the situation!
  9. I read the report and a there are a few things i do not like. Cost A: While such a system has never been built he makes some assumptions which are not well thought. First he excludes the cost of land. Of course you can built a very low cost rail or road if the land is free. but in urban environment the free space is very scarce. So new traffic routes have to be built elevated or underground. Cost B:Next wrong assumptions are the materials. Maglev use Aluminum coils and not copper coils. Simple as many coils are needed and Aluminum is cheaper than copper. Transrapid also uses aluminum coils. Cost C: Obviously this PRT type claims to capable of running 200km/h. Within a city there is no need to build all tracks to 200km/h. As the motor is built to the track a 50km/h track would have a much lower cost as a 200km/h. Network layout: There are not a many on/off ramps needed just before and after every town. Within the city vehicles can travel at lower speed so the speed between vehicles are matched. Capacity: A very common misunderstanding is, that capacity is higher if the speed is higher however this is only the case for fluids not for any vehicle. As a tracked vehicles must comply with the so called brick wall rule. That means any vehicle must be able to make a stopp before hitting the vehicle in front of it, given the first vehicle hits an imaginary wall. Spacing of vehicles traveling 200km/h will be 47s when a deceleration of 1.2m/s^2 is used. Obviously running 2 person vehicles at 200km/h gives a very low capacity and is not likely to financially viable. Maximum deceleration is limited by law even modern trains could accelerate and decelerate faster. Even high speed trains couple two sets together to increase capacity instead of running the to sets after each other. For the same reason highways and roads have their maximum capacity between 60 and 80 km/h. Its only logic that a PRT has a the same capacity like a road for vehicles per minute. Slightly higher as there are no human factors and silly behaviors like lane changing. So the way to increase capacity it to put more passengers into a vehicle. Instead of using a SUV with an average 1.2 person per vehicle use a Jeepney with an average 12 persons per vehicle and the capacity of a road just has increased by a factor of 10. Another way would be coupling vehicles together like the railways do and uncouple it when the use separate routes. But this will be to complex for a PRT.
  10. I'm not saying that PRT and gondola's are exclusive of one another. Simply that we currently don't have any true PRT examples. As I've stated before, the WVU system isn't a PRT system - it's an AGT system. Secondly, the system at London Heathrow should hardly be considered PRT given the station configuration and lack of network capabilities. PRT advocates often invoke these systems as examples of PRT technology yet they don't actually meet the definition of PRT.
  11. Interesting comparison of PRT and the SFU gondola proposal. See: http://www.mist-er.com/images/FAQ4.pdf
  12. "WVU system isn’t a PRT system – it’s an AGT system." Is same way the system works! Direct transfer from one point to the other! No intermediate stops! Bit like 3s and 2s are both gondola-systems, but one transports more people then other! This week Ultraglobalprt layed the first stone in Amritsar of a system that will enter your consideration and configuration of PRT! http://www.fairwoodindia.com/personal-rapid-transport-system-amritsar
  13. Let's just clear up the WVU system issue: It is an AGT system with off-line station capabilities. Off-line stationing capabilities, yes, are one of the defining features of a true PRT system, but they are not the only defining features of a PRT system. There's a difference there and that difference is very important. The WVU vehicles are built to carry a maximum of 20 people. Now, for the off-line station capabilities to be useful, every single person in a vehicle would have to be travelling to the exact same station - no guarantees there. That's why the system often operates in scheduled or circulator service mode much like a standard bus with regular stops along its route. True it can operate in "on demand" mode, but that's only in off-peak times and the wait times for a vehicle are actually (get this) longer than in the scheduled mode. See the problem? PRT claims to provide on-demand vehicles whenever a person wants it (within reason). And yet when the WVU system operates in "on-demand mode" wait times for vehicles are longer than when the system operates in scheduled mode. The one quality that makes this system PRT causes another condition to thereby cancel out the PRT designation. It's a complete paradox and is at the heart of why this isn't PRT. Let's not even deal with the fact that vehicles carry up to 20 people - hardly personal. From what I understand the WVU system is an incredibly innovative, unique, efficient and all-around wonderful transportation system. It's just not PRT . . and it's completely disingenuous for the PRT community to claim it as such.
  14. I agree waitingtimes at WVU at "on-demand" must be a problem! But I do not know enough about it to know why! In Heathrow it is also scheduled to use direct lines between the terminals! So that multiple people can sit in the same pod. The Amritsar will be also a mix of the WVU scheduled system, and at same time at extra cost you could get door-to-door service! If I understand from your explinations, you have more problems with the word "personal" in the "prt"-system as the "on-demand" of the system! ;-) Maybe we should just call them "ODT" (on-demand-transit) ;-)

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