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Thoughts about the relationships between transport and the urban area it serves

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| Technology | The Guardian

The last time I wrote about Personal Rapid Transit (PRT) I got all sorts of raspberries from people unimpressed with an old prototype in the US. This piece is about the new Terminal 5 at London’s Heathrow Airport, which looks like it will be a significant step forward to the sort of PRT that is going to be needed all over the place.


It seems to me that we need new kinds of transportation. Owning cars, and keeping them standing around doing nothing most of the time, is clearly very wasteful. The automotive industry for most of its existence has not been about mobility or accessibility – it has been about selling a dream – an illusion – of personal freedom. That has very nearly cost us the planet. Automotive dependence is bad for us. It ruins our health, and our sense of community. It kills and maims more of us than our current, plentiful, global conflicts. It has very nearly destroyed one of mankind’s most significant achievements – the city. We seem to have turned back – if the straws in the wind in more civilised places than this are any indication. Congestion charges: woonerfen: rental bikes: car sharing: car free days: pedestrian precincts: no through roads for cars in the city centre: shared ride taxis: light rail.

The biggest issue that we face is making the alternative to the car attractive enough. A mode which comes when you want it and takes you where you want to go, but then goes off somewhere else – so you don’t have to worry about parking. In fact, its bad enough that all those wonderful machines sit idle nearly all the time, but the space they occupy is ridiculous. PRT is the mode whose hour is nearly here. At long last we have the sort of computing power to cope with the huge number of routing algorithms that are needed to make it work. We are nearly at the point where the vehicles can drive themselves. And we may even be able to come up with a drive train that does not need huge amounts of fossil fuel – that will be essential since we will not have that for much longer.

PRT is better than a bus but cheaper than a taxi – which is pretty much the market niche that needs to be filled if we are to shift away from the current mode share. There will be those reluctant to give up their cars – and there will still be significant markets for mass transit – but PRT can drive up the middle.

I think the next time I go to LHR I will be flying BA,  if only so I can check out the PRT at T5.

Written by Stephen Rees

October 10, 2007 at 9:04 pm

Posted in transit

10 Responses

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  1. You may wish to check out this video about it:

    Nathan Koren

    October 10, 2007 at 10:49 pm

  2. If they can manage to develop the system properly, I say go for it. The two main problems, as I understand it, have always been: 1) having a large enough market penetration in a city for the system to work (aka: build a network), and 2) economies of scale to reduce the astronomical price of the system.

    PRT was deemed dead a long time ago. But I suppose if they are still developing the technology, I see no reason why it’s time couldn’t be coming. I frankly am quite excited at the prospect of a PRT system, but there’s always been the thought that “it’s too good to be true”. Who knows though.


    October 11, 2007 at 1:11 am

  3. This one is technologically feasible, but Paul’s analysis is absolutely correct – it’s about the network effect and costs.

    Let’s rephrase the question – you’ve got a billion dollars burning in your wallet that you want to plough into transit. Do you build the Evergreen line or do you build 10 miles of PRT (which would be a realistic estimate of how much you can do with a billion)…

    … or you can build a new bridge crossing the Fraser River. 🙂

    Sacha Peter

    October 11, 2007 at 9:30 am

  4. There is no doubt in my mind that the Evergreen Line is the first priority for this region – as it was at the time that the Canada Line jumped the queue.

    PRT will be needed in areas where it is difficult to get high quality transit conventionally. And people movers at airports are a good start. By the way, that was what SkyTrain was originally designed for.

    There is no one solution that will be always right in every circumstance, but I can see a place for PRT. In most low density suburbs I think more taxis, shuttles, shared ride and “para-transit” will be cheaper solutions for now. Similarly for longer distance commutes, high quality highway coaches on exclusive lanes will probably be adequate and a cheaper solution than commuter rail – at least as a short term measure. Both GO Transit and WCE use motorcoaches to supplement their train services.

    I suspect as well that the original use of PRT – to provide internal rapid movement within a spread out campus – will have a lot of similar applications. Have you also noticed how much transit is built into big theme parks?

    Stephen Rees

    October 11, 2007 at 10:00 am

  5. I think that PRT would be a great idea, but using regular roads rather then a dedicated system of rails. Sooner or later that could happen given the advances in computing…For starters we could dedicate lanes on regular roads for that type of transport…

    Dejan K

    October 11, 2007 at 1:00 pm

  6. There seem to be some misconceptions of how expensive PRT is, which need to be challenged. Most of the manufacturers believe that they can build their systems at costs between $5 and $15 million per mile. The lower end of that scale is not believable at preset, as it would require a fairly significant economy of scale to achieve (vehicles on a production line rather than being hand-tooled, et cetera), which no early PRT project will be large enough to produce.

    That said, the actual current production costs don’t have to be guessed at: you can look at the Heathrow project. It is fully engineered and costed. Pylons are being set in place. Production vehicles are being delivered from the manufacturer. The actual real-world cost of these things is no longer a matter of conjecture, and they all indicate that the project will indeed come in at under $15m per mile. So Paul and Sacha’s implication — that PRT will necessarily cost $100 million per mile — are off by a factor of at least six.

    This reminds me a bit of what people coming from traditional mainframe computing backgrounds used to say about personal computers: “wow, that functionality sounds fabulous, but nobody will pay millions of dollars just to have something like that in their home”. A paradigmatic jump was required to even understand what was being proposed, and for many people this jump was just too confounding to make. How could “better” ever be “cheaper”? It made no sense! But eventually they were able to come around.

    Also, I should note that ULTra isn’t the only game in town. Some Korean-funded Swedes have been making remarkable process in the last few years. This video was just released a few days ago:

    Also, there are some very good reasons *not* to put PRT vehicles on regular roads. For one, that would require the vehicles to be as heavy as conventional automobiles, since there are many safety and comfort features which a dedicated guideway obviates the need for (steel roll cages, heavy-duty suspension systems, et cetera). Heavy vehicles are a problem, as that would eliminate the energy-efficiency advantage of PRT, and drive up the operational costs.

    Also, I believe that for reasons of liability, it will be a very long time before we see fully-automated vehicles operating in mixed traffic at high speeds. The reason is simple: when somebody driving a Ford (for example), and happens to run over a small child, who do you sue: the driver, or Ford? Right. Now repeat that thought exercise with an automated driver, and multiply the resulting lawsuit by the amount of public hysteria that the first such “killer robot” would generate. With this utterly inevitable scenario in mind, would *you* be willing to be one of the investors funding the deployment of such a system? Didn’t think so.

    Nathan Koren

    October 11, 2007 at 9:25 pm

  7. I am a passerby who often comments on PRT discussions.

    I’ll add to Nathan’s point about automated drivers mixing in traffic. It’s one thing to have a car that parallel parks – a very bounded, very low speed application with almost no safety concern. It’s quite another to have automated systems performing realtime road navigation, obstruction detection, etc. I believe we are probably *decades* away from such a system, mainly because (1) it is inherently an artificial intelligence problem (2) current state of the art artificial intelligence is way too noisy for something as precise and realtime as piloting an automobile.

    Any autopiloted car solution would have to be on dedicated lanes of a highway, where there is effectively no interaction with human-operated cars, bicycles, or pedestrians. This is logistically difficult without grade separation, which brings us back to plain old PRT.

    One possible alternative is dual-mode PRT – automated operation on guideways, human operation on roads – but there are other reasons why dual mode is problematic (mainly the engineering tradeoff that the vehicle must be heavy to operate on roads, light to operate on guideway).

  8. […] In the dicussion on Personal Rapid Transit doubt was cast on the idea of cars that drive themselves. Well The Guardian today reports on the […]

  9. i saw prt years ago and have just rediscoverd it.
    like many i thought it had died a siglant death.

    but when i see what progres has been made whel my brain starts to buble withe idea’s.

    the pods have becoum realy nice things.

    for introduction i’m a male 32 structural designer living near denhaag in holland.

    and whel i take the tram to work every moring from my suburbian flat , wich is a 45 min ride.

    over here we are spoilt withe publick transport , in fact i can take 3 diferant routs to work ( bus tram etc ) al in 45 min time.

    and over here trams and busses moastly have there own dedicated lanes.

    they did this years ago to speed up trams so they did not get cought up in trafic.

    when i saw the prt’s and how far it’s going on heatrow i thought , wow cancel the trams and replace them withe pods.

    denhaag has such a dence tram network and buslanes that if there was a pod stop in front of my work insted of the busstop it could bring me al the way home.

    and this al in my private cab , and direct.
    not like now that i have to share and change trams.
    it would also no stop , and just drive constantly , wich would make a 45 min door to door drive to i think at least 20 min if not les.

    and yes there would be the ocasional ground floor crossing when it crosses intersections.

    but they are now garded by stop lights , and a car is just as much to drive into a tram as a prt.

    so i think that would not matter and be a problem.
    in fact a prt would see a car coming that has gone past red and stop therfore making it safer.

    you could also put a tunnel in thus going under crosings.

    and yes that would be an expence , but les expensive if they were made prefab , this al becouse the hight of a prt is les than a tram would need.

    i think it’s a worthe wile expence to put in.
    and dont forget the savings you wil have.
    no rails to realign , no extra overhead cantanary and masts.

    and you would gain a go as you want sythem.

    i would love it , to bad it probably wont be made before i’m dead 😦

    but i also think that new housing developmants should put this systhem in when theye are planning.

    here we put in trams and publick transport just as the 1st new setlers move in and i think this kinde of systhem would be better insted.

    i must say i hate driving specaly after a bussy day behinde a screen i cant trust my eyes…

    i would love to just close my eyes in a pod and wake up home…

    i think counsils should come together and put this systhem in when developing new towns and refurbishing older earea’s.

    it can be integrated nice withe the enviroment then and it would def get people out of cars when they can go point to point insted of stopping where others want to stop.

    even when you replace trams withe it i think it would stop peak congestion , like now when you see like platforms ful of people.

    i would love to see how it goes at heatrow and i would like to see it soon near here.

    i think the makers should push counsils round the would to acsept this sythem..

    also a good thing to put into theme parks , the next expo , and why was this not integrated into the 2010 olypics ??

    it would have been a great advertismant round the world for british inventivnes and to promote the prt…. :-S had anybody told boris ??

    bit sad…

    i just love it , it reminds me of the “x- track”toy and that is a blast to build and play withe….

    i cant see people not liking it.


    April 7, 2009 at 1:52 am

  10. […] this about extending Para-Transit, this one about Personal Rapid Transit and  Michael Geller promoting TukTuks. But perhaps the central argument is in this one about […]

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