Sunday, May 31, 2009

35> Troubled

I am a troubled by the business model that would-be PRT providers are taking, either by choice or necessity. The first thing that troubles me is the lack of emphasis on the transformative potential of the technology. I understand that they want to be professional, to focus on immediate doable objectives. But the immediate doable objectives are such that they really are not “the only game in town,” but rather an arguably risky way to achieve a limited set of goals which may not be that well suited to PRT in the first place. It is no wonder light rail is so vocal in its derision or PRT, since the PRT companies have chosen light rail as the sweet spot in the market. Somewhere in the mix, the whole promise of PRT goes missing.
I would like to see a long-term vision for PRT adoption added to the mix. Without that, the future of PRT could just be the sporadic limited construction of incompatible systems, assuming that they all work as advertised, are within budget, and don’t end up being a technology principally beneficial to the makers of the deal.
Is it not possible to go head-to-head with roads, instead? To be a commuter alternative instead of a downtown crowd shuffler? I’m afraid the limits of design and business imagination have led away from the true value proposition; a better alternative to the network of urban/suburban highways and roads. It is the power of that network that makes the automobile (and therefore eventually traffic) ubiquitous.
I will say it again. The true value of PRT is that of a substitute for cars and roads, not a substitute for light rail or trolleys. PRT companies need to figure out a way to leverage the full value of proposition of their product. I would submit that that would entail a fully articulated long term plan that reaches well outside the realm of what one company can do. It requires all PRT companies, environmental groups, standards organizations, as well as partners in government and education. Until they have a plan for a system that you don’t need to commute in your car to get to, I’ll keep reminding them.

12 comments:

Michael said...

What you seem to be forgetting is that roads are already everywhere. Unless you have a few Billion$ in loose change, how do you propose to build enough guideway? One of the cool things about PRT is that it is modular. Start with a Downtown circulator and then expand it. Just think how much guideway it would take to cover a place even as small as Tucson.

akauppi said...

Have you read Nathan's article:
http://faculty.washington.edu/jbs/itrans/Koren_PRT_Essay.pdf

To me, it seems he has a good overall view of what can and what cannot be done. If what you are suggesting would work, it would have done so in the 1970's. It did not.

My home island, just off Helsinki capital, is a cute example on how PRT's could eventually embrace larger communities. There's some 20000 people on this island, meaning it's rather densely populated. It has only three exits to mainland. Replacing existing bus traffic on the island (with PRTs) is a realistic idea, especially once the new metro will come here. PRT will then cater for internal traffic as well as feed people to the two metro stations.

Note that this is still NOT the primary case I would suggest for PRTs in my home country. But its isolation makes it a rather good trial ground, once that time comes.

Anonymous said...

I think nearly all PRT developers have a large scale vision. Not emphasizing it is rooted in the politics. The more change you envision the more people will rise up and resist it. The resistance will rise faster than the support. There's good reason to look for niches to start.

Bengt Gustafsson said...

I basically agree with mr Anonymous, but at Beamways we are poising our system for city-wide use.

Roads are going to be needed as a complement unless the guideways are very heavy duty to be able to carry heavy loads. This is not something I would recommend.

I would also like to recount some figures which have been calculated by the city of Uppsala, Sweden for a study we do for them, with the honest intent of investigating the possibility of using PRT for a majority of intra-city travel. Here are the projected ridership figures:

walking: 80 000
biking: 136 000
car: 113 000
PRT: 141 000

So, PRT has a higher mode share than the car. These are the numbers from the City, not by us.
Inhabitants are 235 000 in this scenario for 2030.

Dan said...

Dan The Blogger is back from the Wilds- sort of..now in Kentucky...
Welcome, Michael. Yes, they are everywhere. Funny you should mention Tucson, as I spent the better part of the last two years and actually started this blog there. Easy town to get around, compared with most… Yes, there is a huge amount of track to be laid, so it needs to be really, really cheap, versatile and well thought out. It needs to be such a great success that raising money for expansion is a political and financial “no-brainer.” I am not sure that starting downtown is really the way to go, however. Read on…
Akauppi, I’ve got to hand it to you, nice work. You win the prize. That essay you mentioned is very insightful and right to the point of my post, and speaks directly to what everyone else here has written. There are clearly good lessons to be learned from it. It also makes me realize that some of my own “insights” were merely shadows of more refined points that he makes. For example, some of my aversion to the head-to-head competition for the downtown market is probably a “gut” recognition of the near futility of that effort, (I’m speaking about the U.S.) which he so well explains. P.S. Selling PRT to an island is certainly an interesting idea. Bermuda, anyone?
Anonymous, you certainly have the niche thing right, especially in view of the points raised in akuappi’s paper. I’m not sure people are as resistant to change as you say, (assuming it’s positive) however. One of the long-range vision aspects I was talking about was aesthetics. If the downtown “niche” creates a de facto standard that is less than satisfactory when expanded into a larger network, then that is a real problem. I regard, for example, the track-on-bottom approach (need for raised stations) as such a standard. It’s perfectly fine for downtown. It’s just not optimal for expansion into other venues, one reason being aesthetics. If the gondola approach is used, steep slopes are possible, which means the track can be placed quite high. This in turn makes the vehicles less obtrusive in every respect. Concerns with privacy, noise, blending with the neighborhood, etc. can all be minimized by having the track higher. The "resistance to change” you speak of will hopefully be minimized with this type of flexibility.
Bengt, Thanks for putting the whole thing in perspective. The figures you provide show how totally different things are on this side of the Atlantic. More bikes than cars? What about in the winter? In the States the ratio is probably less than 200 to 1 on a sunny day. As for roads it’s certainly true that they are here to stay. I can’t see PRT delivering concrete, although the heavy truck thing raises a question about the need for scale in delivery. I suppose, in a post PRT world, mixed concrete delivered in, say, sub 100 kg. loads might actually be a lucrative business model. So might many other deliveries currently bundled into heavy loads.

resonance said...

I think commuter transit is the best proving ground for PRT, both technologically and psychologically. I also think eventual PRT systems will be the result of incremental implementation, rather than a full PRT system popping up somewhere.

There is an inherent distrust and ridicule of anything looking too futuristic, and the "podcar"ness of PRT appears to be the principle driver of such criticism, justly or otherwise. I think the best thing we can do for PRT's image is to relax the "door-to-door" and "private vehicle" principles for the initial systems.

What gives PRT its advantage is less personalized transit than optimized transit--making the most efficient use of people's time and money. This is best achieved with direct and demand-modulated transit. But what the resulting system looks like depends almost completely on the demand requirements. To achieve the desired time, energy and cost efficiency for movement among low-density areas (suburbs) generally requires very personal vehicles, on the order of the size of a standard passenger automobile. But movement along well-established commuter routes--existing highways and transit lines--consists of many more concurrences of demanded origin-destination pairs in a given period of time. Concurrency of origin-destination pairs in small windows of time means the possibility of grouping riders together without sacrificing travel time, and with only a small sacrifice in waiting time. Further, there are clues available to us to the level of concurrency of trip demands that exists on a given route. Each existing nonstop commuter bus carrying 50 passengers from X to Y departing every hour, for example, can be replaced with 5 railcars of 10 passengers each, one departing every twelve minutes, or ten cars of 5 passengers each, one departing every six minutes. Thus a nonstop trip with an average wait time of half an hour is turned into a nonstop trip with an average wait time of 3 or 6 minutes.

[continues next comment]

resonance said...

[continued from previous comment]

Even when a high degree of concurrency of origin-destination pairs is not to be found, implementation of few-stop shared transit is still probably a desirable improvement over every-stop transit and even some "express" transit systems (here's looking at you, Select Bus Service). Instead of offering nonstop travel, a shared railcar can limit itself to carrying passengers only between a finite subset of stops--like an express bus or train, but much more selective. Alternatively, a passenger can be guaranteed a maximum number of intermediate stops when he selects his destination, with differential pricing so that nonstop trips are available at a premium while "local" trips are available for a much reduced fare. This is also a nice way to make productive use of "excess" capacity.

The CyberTran system (apparently currently being developed under the umbrella of eTranzUSA) seems to me to be the closest thing currently in development to this kind of set-up. I'm not sure how its routing works but it likely would not be that challenging to program it to provide service as described above along a busy commuter corridor. The cars are shared with a capacity closer to that of a large van or a bus, but smart routing allows for minimizing trip and waiting time. The fact that vehicles are sized more closely to those of the type of transit people are already familiar and comfortable with should do a lot to help with the image problems PRT suffers from, while the benefits of high trip concurrence that commuter corridors provides can help the system achieve sufficient efficiency improvements over conventional transit to warrant investing in the new system. Further, situation along an existing commuter corridor means that infrastructure can be built alongside or even on top of existing transportation infrastructure, reducing the total capital cost and allowing a father-reaching system to be built with a given amount of funding.

Commuter service also serves a function that many people make use of every day, and so better demonstrates the benefit of such systems to people's quality of life than does a system that is only used occasionally, like an airport or theme park circulator. When people's commute times are dramatically reduced they'll start swearing by this kind of transit and want to see more of it in other settings.

Dan said...

Dan the Blogger Responds-
Welcome, Resonance:
Interesting thoughts. What you say reminds me of a successful transit model I have used in Houston. The airport there has 4 or 5 terminals, and the city is extremely sprawling. Shuttle vans are radio dispatched to pick up selected passengers at the various terminals until there are enough to make it worthwhile to make a trip to a particular part of town. At peak hours, the wait times are very short and the drop-off points are basically on the way. Sometimes you’re the first one off, sometimes you’re the last. Taxis, in many cultures, are also usually shared.
This model has important ramifications for overall PRT design because it would increase the structural requirements of the track. If you have been following the discussion about modifying the system for the disabled, you know that I have been trying to champion the lightest gauge track possible because of the importance of the “network effect” where the system’s value rises exponentially as new geography is added. Your proposal has a dampening effect on that geographical expansion. It has, however, the advantage of being able to exist within the dual system I described for accommodating the disabled. It also has the advantage, as you pointed out, of being feasible in simple loop configurations where traffic is so bottlenecked that no further ground based transit is practical, so it has that stealth, foot-in-the-door factor going for it.
The system you describe, if I understand it correctly, would default to “regular” PRT if no other passengers could be found to share the ride. It is not hard to imagine a multi-mode system where passengers have a choice of private or shared, especially if larger vehicles must be both common and dispersed anyway.
I am not sure about it being easier to accept, however. Size adds cost and larger profiles down the line, as well as (probably) more supports. In the Transit Authority considerations I have looked at these were not trivial concerns. As for the “Podness” factor being a negative, I think you have a point. Beamway’s new car design seems very trolley-like, almost having an old-world feel compared to some more bubble-like designs. I can see it fitting in very well, especially in the Europe or older North American cities. Another way around the “Podness” issue is to simply raise the whole system higher. It’s easier to accept something that doesn’t have to be in your face. Smaller and higher has some advantages in the expected street-by-street battles that always accompany public works projects, even road widening. From the point of view of trying to build a network, those advantages get repeated again and again. Therefore that has, so far, been my approach, but I must say I am willing to explore the limitations of that philosophy.
This is a very constructive topic. I hope some other readers weigh in on this.

Bengt Gustafsson said...

Regarding resonance's post I can just say that this ridesharing would work fine in a corridor oriented system, but in a networked system there are just too many destinations to choose from. One important use for this is however unloading larger vehicles, typically regional trains, onto the PRT system. In this case you have a large group of people within which you can find subgroups with common destinations. Ingmar Andreasson has simulated a scheme where certain station berths are signed for certain destinations when a train arrives (based on statistics of course). He then gets a mean occupancy of 2.5 for a typical case, which is very good!
(This is for max occupancy of 4). This is still a fairly small PRT network, but even if the network is larger there will be a fair amount of sharing possibility in this type of scenario.

A paper describing this scheme along with some other capacity enhancing methods is here:

http://faculty.washington.edu/jbs/itrans/whatsnew.htm

Look under June 2009. Lots of other interesting stuff on this site, which is the "hub" of PRT activity.

This mailgroup is also interesting:
http://groups.google.com/group/transport-innovators/

resonance said...

This doesn't necessarily have to be compatible with or directly connected to a PRT system--and probably shouldn't be. Like Bengt says, it would eventually be a high-speed connection between PRT feeder stations. If it only runs on freeways, it can be whatever configuration you want that doesn't need more space than the width of a freeway lane.

"I am not sure about it being easier to accept, however. Size adds cost and larger profiles down the line, as well as (probably) more supports."

The point about acceptance was about psychology, not economics. People would be more comfortabe with something that looks at least somewhat like existing transit than something that looks too futuristic. Nonetheless, it would likely be cheaper than the existing transit alternatives for providing corridor service.

In a freeway setting, in the median or on an inside lane, there is not really any need for elevated guideways at all, except where there is an exit or entrance ramp on the left side of the freeway, which is rare. So the guideway could either just be the road itself, augmented with perhaps some guiderails or whatever you need to keep the vehicles "on track", or it could be a full-blown steel rail track, which would provide higher speeds and efficiency and better safety. The link I provided about "interstate rail" is a good overview of the possibility. Of course, you have to take a freeway lane away from people, but if you give them a high-speed high-throughput congestion-free corridor in exchange, they might not mind so much.

"this ridesharing would work fine in a corridor oriented system, but in a networked system there are just too many destinations to choose from."

Yes, that's why I proposed it for a corridor, not a network. My point is that this operates sufficiently similarly to PRT to take advantage of certain efficiency benefits, while looking sufficiently similar to conventional transit to not be scary to people.

I'm beginning to read "Fundamentals of PRT" and this corridor GRT idea is mentioned in there, so there must be some merit to it.

"Lots of other interesting stuff on this site, which is the "hub" of PRT activity."

I don't know about the hub, but it's certainly a good resource. Wish it had an RSS feed.

Dan said...

In response to Resonance’s last comment-

I get it now. You’ll have to forgive me for seeing what you said through the lens of PRT, since that is what I concern myself with here. I agree that your system, optimized, would be different than PRT structurally. The fact remains, however, that one of PRT’s biggest problems is that nobody is willing to start off with a whole network, so there is substantial resistance to laying down the first run of track. The system you describe works with a minimum of stations, cars, and track. Therefore it seems to me that the idea has merit as a path toward PRT adoption, if a PRT network is indeed the eventual goal and not GRT. That is not to choose favorites. GRT, as you describe it, would seem to like a very good idea. I must say, though, personally, I’d like to see transportation in general raised off of the ground. The amount of pavement in cities like mine actually changes the local climate, and don’t get me started about habitat fragmented into “islands.”

John Cleeland said...

If we are competing with the car, a small car size is OK.
PRT does not slow for congestion nor stop at intersections, nor do you get booked for speeding, drinking or texting so it wins hands down. Put aside safety and pollution, that is a problem for others. You don't have to find parking.
Second point: if we are concerned about vehicle size, let the system join up vehicles in real time. Surely that is for a later date when and if we have congestion problems and it is a simple software add-on.