Personal reflections on urbanism, urban life and sustainable urban design in Wellington, New Zealand.

Monday, April 10, 2006

Pod people

Pod image adapted from http://www.atsltd.co.uk/media/pictures/There was quite a media splash at the weekend from promoters of an "ULTra pod" Personal Rapid Transit (PRT) system. They want the council to fund a $1m study towards a 6km elevated central-city loop of 4-seater electric "pods" that are claimed to offer the best aspects of both personal and public transport. They would be cheaper than taxis, more space-efficient than personal cars, and unlike trains or buses, would deliver you straight to your chosen destination without stopping along the way.

I remember being excited about these when I saw a display about them at Sydney's Powerhouse museum about 5 years ago. But since then, I've seen a lot of less appealing information about them. There's even a site called PRT is a Joke that goes so far as to claim that PRT is either a scam or a "stalking horse" for the road lobby:
PRT proponents can say things that the highway boosters could never say, such as "people don't like to ride with strangers". This anti-transit propaganda divides and conquers the opposition to highway projects.
While I haven't studied the subject in enough detail to examine such extreme claims, the proposal certainly has a whiff of Ogdenville, North Haverbrook, and Brockway about it, and there are some real issues with PRT. For example, the promoters claim a capacity eight times that of buses and four times light rail. But this seems to be based upon the unrealistic assumptions that the pods would always be full and that they could run three seconds apart at 40km/h. If you're promoting this on the basis of not having to ride with strangers, then imagine how much more uncomfortable it would be to be stuck in a tiny pod with them than in a bus! So 2 people per pod seems like a more reasonable average. Also, running pods that close together wouldn't allow for safe stopping distances: a more sceptical analysis suggests that 15 seconds is a more realistic headway. Thus, their capacities seem to be inflated by a factor of about ten, and any advantage over more proven modes disappears.

Some of the other "advantages" also seem irrelevant to this specific Wellington proposal. The main selling point over traditional public transport is that you don't have to change lines: you select your destination, and the pod itself will switch tracks as necessary to take you there. After struggling through the London Underground with luggage more times than I care to remember, this is certainly an appealing thought! But this proposal is for a simple loop, so there would be no changes to make anyway, and it would seem to have little "personal destination" advantage over a bus or tram.

Also, our main issue is not so much in getting around the CBD as in getting to and from it. There will still be a mode change involved for suburban commuters (switching from cars, buses or trains at the railway station or Courtenay Place before getting into their pod) which is always a big disincentive. One of the main advantages of a light rail system is that it could switch from existing rail lines to the city streets, so that you could travel from Johnsonville or Petone directly to Courtenay Place. A more extensive PRT network might also offer this advantage, but it would cost a lot more than the $50m quoted for the downtown loop.

The other advantage of light rail over PRT is that it's proven technology. It's been around for longer than the car, most European cities couldn't function without it, and even the USA is catching on. PRT, by comparison, has never been installed in an urban situation, and despite the glowing news continually reported by PRT backers, it never seems to get anywhere. In fact, the Cardiff trial that the Dominion Post article mentions was abandoned in 2003.

And I haven't even mentioned what 6 kilometres of elevated concrete tracks would look like along Lambton Quay and the waterfront!

I'm not willing to dismiss this proposal out of hand, since it's good to see someone seemingly promoting serious investment in sustainable public transport. Have a look at the promoters' presentation to the council (2.5MB PDF, PRT presentation starts at page 6) and the Wikipedia article on PRT as well as the more sceptical sites that I've linked to above. Read what other people are saying about the potential of light rail for Wellington. Then we need an informed discussion about the options, and at the very least, this proposal may kick start debate about alternative transport options.


At 12:04 pm, April 10, 2006, Blogger Will de Cleene said...

Yes, the PR assault was swish wasn't it? I am quite happy to dismiss the Pod idea out of hand. Legs is cheaper.

At 12:32 pm, April 10, 2006, Blogger noizy said...

upon seeing it on the news, my wife and I spontaneously and simulatneously broke into The Simpson's 'Monorail' song, from the episode where Springfield is tricked into buying one of the contraptions.

At 12:36 pm, April 10, 2006, Blogger noizy said...

aha - missed the reference to 'Ogdenville, North Haverbrook, and Brockway' on my first read through.

one step ahead, as always, Tom...

At 1:05 pm, April 10, 2006, Anonymous Anonymous said...

I, too, was wondering about that three second gap, Tom. Seemed a bit close to me - I was envisaging the passengers leaping from the moving pods into padded disembarking zones. Getting on, however, is a problem I haven't tackled yet. And I agree with zippy's comment on legs being cheaper, although perhaps this is the way to go - might solve the whole getting into and out of the city problem and get rid of roads entirely in one fell swoop!

At 1:18 pm, April 10, 2006, Blogger Baz said...

This comment has been removed by a blog administrator.

At 1:20 pm, April 10, 2006, Blogger Baz said...

I followed the link about Cardiff to see what had happened, but it stated that the trial had been "helved". Not speaking Welsh, I assume that means that the place ended up in a similar state to North Haverbrook, at least enough to finish off Gene Pitney.

At 1:38 pm, April 10, 2006, Blogger Tom said...

Mike: I had to look twice at that New Scientist article to double-check that it wasn't dated April 1. "Techno-trousers, ex-NASA, fantastic for walkies".

I still think they should have moving walkways all over the city.

Okay, so that's references to Wallace & Gromit, Seinfeld and the Simpsons. Perhaps we should base our analysis of public transport on something other than pop culture!

At 2:05 pm, April 10, 2006, Blogger Baz said...

Talking of Wallace and Gromit, would it be too off-topic to mention the giant rabbit menacing Northumberland? http://tinyurl.com/ezzh9

It would? Oh... sorry. In that case, make mine a vote for a light rail / shank's pony combination, which would be ideal for Wellington. The PRT is overkill for what we require, even if it can be made to work as claimed.

A bigger version might be of benefit to Auckland, though...

At 2:16 pm, April 10, 2006, Blogger Tom said...

I agree that light rail would be ideal here, starting with either a Golden Mile route or a Golden Mile/waterfront loop, then extending in stages to the Basin Reserve, Hospital, Newtown and airport.

Shank's pony will always be an important part of the deal, as you rightly point out, so it's important to make walking between stations and destinations as easy an pleasant, too. We need more sheltered pedestrian-priority routes between the Railway Station and Lambton Quay, city and waterfront, and city to Harbour Quays. Perhaps as more development occurs in these gaps, the new buildings (e.g. the Holiday Inn that's in progress) will provide enough shelter with their verandahs, but if not we'll have to have more of the sheltered walkways that we already have on part of the station/CBD route.

At 11:43 am, April 11, 2006, Anonymous Anonymous said...

As I understand it, the idea is that there is a big fleet of relatively cheap pods. Journeys are nonstop so each pod is quickly reused over and over, so high capacity might be possible. The concept is valid enough to satisfy the EU, and it's going forward with a first installation at Heathrow. Let's wait and see!

At 12:25 pm, April 11, 2006, Anonymous Anonymous said...

With lightweight vehicles and networked, fully automatic computer control, short headways ("gaps") are possible, probably in the one-half second range.

Wikipedia has a detailed article about the concept.

At 12:28 pm, April 11, 2006, Anonymous Anonymous said...

Read about rebuttals to the Light Rail Now article about PRT.

At 12:56 pm, April 11, 2006, Anonymous Anonymous said...

When I first read about PRT, I was swayed to the negative by the Light Rail Now "Cyberspace Dream" article and a few other critical analyses. I've since come to realize that Light Rail Now article is basically propaganda. There are a few valid concerns but most of the analysis is flawed and shows a fundamental lack of understanding of how PRT actually works.

PRT is real, and it is a viable technology, despite the claims of Light Rail Now. I've done a ton of reading on it, and I now realize that the theory is sound. Detractors tend to dismiss PRT with generalizations like "it can't handle the capacity" but it's just not true based on what I've read.

Unfortunately, the detractors (like cartoonist Ken Avidor and the Light Rail Now rail advocates) are very vocal in their campaign against PRT. And they can be very convincing, so a lot of people have come to believe PRT is just some piece of vaporware, or worse, an outright fraud. It absolutely is not.

Read up on it (Wikipedia is a good place to start), and you find the same thing I did: that PRT faces a lot of challenges, but it's a very real, very promising technology. And ULTra is currently one of the world leaders in bringing PRT to market.

At 4:49 pm, April 11, 2006, Blogger Tom said...

Hello anonymous's,

There are too many competing claims about PRT for me to rigorously assess its viability per se, but I can think of several reasons why this specific proposal isn't great for Wellington.

Much of the potential advantage of PRT over mass transit is that it gives point-to-point on-demand transport between a whole lot of destinations that won't fit on a single transit line or loop. But the proposal is for a loop, so that doesn't help much here.

In one of the rebuttals (at gettherefast.org), on of the points made is that there wouldn't be the congestion at stations that Light Rail Now claims, because "Large crowds are true of TRAIN stations" rather than on-demand stations. But in Wellington's case, the majority of potential riders would come from the train station, arriving in groups of hundreds at a time. It would make more sense to have light rail synchronised with the heavy train timetable, or even better, to convert some of the train lines to light rail and extend them through the city.

The rebuttal of visual intrusiveness arguments also doesn't seem appropriate to Wellington. The photo of a PRT track in the distance shows a wide-open barren landscape that (thank god) looks nothing like Wellington's compact inner-city streets, which look more like this. At that sort of scale, even relatively slender guide rails and supports would be very obvious, especially against historic buildings. There are many people here who find overhead trolley bus wires too intrusive, and they're just a couple of centimetres in diameter!

So perhaps PRT (once it is a proven technology) could work in some cities, but I don't see this particular proposal providing much benefit. A full city-wide grid might work, but that would cost orders of magnitude more than the $50m quoted for this little downtown loop.

At 1:44 pm, April 12, 2006, Anonymous Anonymous said...

bush whacker, PRT vehicles stop at offline stations to let passengers get off and get on. Headway has nothing to do with boarding at offline stations.

Would "several hundred" vehicles, each at the price of a car, be worse than a few trains at millions each?

Do you actually know anything about PRT, or are you guessing?

At 4:21 pm, April 12, 2006, Blogger Avidor said...

Notice that the PRT proponents never fail to bash LRT?

That's what they do and they do it very well.

The other thing they do very well is waste the time of transit advocates, public officials and citizens.

PRTers can endlessly (Right, Trey?).

Questions; Was this PRT pitch to the Wellington City Council preceded by a public relations blitz? Is there any evidence of shares being sold by PRT companies in NZ?

Sharing information is the best way to put an end to this PRT nonsense.

Dump Representative Mark Olson

At 3:16 am, April 13, 2006, Blogger Avidor said...

Here's the website for the down under PRT called ATN

ATN is so ridiculous and the website so crappy, it reveals what a do-it-yourself hoax PRT really is. It also has all the elements of PRT's lunatic grandiosity including this statement:

"If Auckland employed ATN, then a good starter installation would be a direct
replacement of the rail network, using the same rights of way. This would certainly
be the cheapest and easiest way to begin. It would be crazy to have both passenger
rail and PRT because rail can never compete with PRT - PRT renders rail redundant.
For Auckland urban operation, ATN would operate at about 80km/h. The
guideways would be a combination of elevated and raised at-grade. A total replacement
of rail to ATN would cost about NZ$1-2b."

The ATN guy has probably heard how Taxi 2000 sold stock to suckers in America, so he thinks he can too:

"My goal is to seek investment for ATN. Either financial investment, or investment
by direct participation or both."

...and of course... there's a lot of rail-bashing... a lot:

"Note: New rail lines in America have been a failure on every count other than
bringing federal money into individual states. If new rail lines were not mostly
funded by the federal government it is extremely unlikely they would have ever
been built. America's transport funding policy disaster has led individual states
to treat construction costs as advantages in themselves i.e. local polititians
have seen rail construction as merely a way to bring "free" money into their
economy. In my opinion this is where all the weak "philosophical" pro-rail
arguments have come from. 'Transit choice' was never an argument, it was
an excuse.

...and this:

"Of particular interest is Doug Malewickis' "Kiddy train" analogy. It makes a
clear and elegant statement of the fundamental deficiencies of a light rail
system. If you read this article alone, you will see how absolutely superior
the PRT operational structure is to light rail."

Malewicki isn't interested in working on Skytran anymore...he says Skytran wastes his endorphins.

This is why I say PRT is a stalking horse for bashing LRT...and that's all it is.

At 2:12 pm, April 13, 2006, Blogger Baz said...

Transportation Enthusiast: your statement that PRT is a viable technology is contradicted by the first paragraph of the Wikipedia PRT article...

as of 2006 no PRT project has progressed beyond the prototype stage.

So viability has never been proven. This doesn't mean that it'll never be viable, but it does make any new deployment high risk compared to proven alternatives.

We have the choice of deploying a looped transit system using a proven technology like light rail, or with a technology that hasn't been made to work after 40 years ("but this time we're pretty sure it'll work").

Furthermore we wouldn't get the point-to-point advantage of PRT but we would get the drawbacks -- inevitable cost overruns, safety, visual impact etc.

At 2:43 pm, April 13, 2006, Blogger Tom said...


I think the PR came after the pitch to the council. The presentation that I llinked to came from a meeting last year, and the newspaper article last weekend was the first the public had heard of it.

Regardless of arguments about whether PRT would work at all, I think it's pretty obvious that this particular proposal has no benefit for Wellington.

The ATN site that your Mark Olson page links to shows a map of a "typical" city for which it says mass transit is poorly suited. It sprawls in all directions and has "a network [through which] city people want to go from anywhere to anywhere" and only 10% want to end up in the CBD.

Wellington, however, looks more like this. It's a relatively compact city (by new world standards), constrained by hills and water, and with only a couple of transport corridors along which the suburbs have sprawled. Our workplaces are very centralised (for a city of ~180k, we have ~60k working in the CBD) and public transport is well used (only 45% of CBD workers commute by private car).

The main problem with our public transport system (apart from general underinvestment and lack of capacity) is that the main railway station is just outside the CBD. By converting some lines to LRT and extending them through the CBD to the entertainment district, we'd make public transport much more practical and popular. But making people change from train to "pods" when they pour onto the platform each morning will be no better than having them change to buses.

At 10:28 am, July 24, 2006, Anonymous Anonymous said...

PRT is Dead Technology Chronicle of the Denver International Airport PRT failure and the shifting of $1.2 billion USD of costs to the public from the bankrupt United Airlines.

At 11:46 am, July 29, 2006, Anonymous Anonymous said...

The failed Denver automated baggage system is not / was not PRT.

At 10:13 am, November 07, 2006, Anonymous Anonymous said...

It is quite amazing, i.e. the level of YOUR and GENERAL ignorance, ill will etc.

If it wasn't for some of our ancestors who climbed down from the trees, you'd still be living there.

Anything new is always creating an indiscriminate loughs of idiots, who think they have some brains.

Hence the PRT critics have a field day, UNTILL the time, when they start using PRT as they are using aircraft. But even Lord Kelvin, just a few years before Wright Bros. made their historic flight, DELCARED under the allmighty authority of science, that "nothing heavier than air will EVER fly".

Well, just as well that Wrights didn't read this enlightened "prophecy".

You, and all those moron derriding the PRT systems, seem to be in the same vain. Plain stupid, ignorant or without any imagination.

But don't worry. Most of this planet is made of people like yourselves. Fortunately the progress is ONLY made by people who fly in the face of the "common wisdom".

If it was up to you, we'd be sailing to new zealand on rafts from Polinesia.

I came across a new PRT system, seemingly much better than ULT'ra and it happens to be by our compatriot, who is now living in Poland. If you want to be honest to yourself, then check it out and see if you still think PRT is a stupid idea. Wash your brain the right way :)

At 10:17 am, November 07, 2006, Anonymous Anonymous said...

oh, sorry, I forgot to mention the website. It is www.mist-er.com

Do your worst ...


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