

The Future of Ground-Based Transportation Systems - Brajeshwar
http://swiftprt.com/blog/2011/12/the-future-of-ground-based-transportation-systems/

======
sanjiallblue
I really like the idea of a fleet of computer-controlled electric cars that
function like an on-demand taxi service.

Think about it, you need to leave for work at a certain time? Just jump on
Google Taxi (I use Google as they're the only company that has working
driverless cars that I'm aware of at the moment), log-in using your account
(that you either pay per ride, weekly, monthly, yearly, yearly+ etc.),
calculate your commute, and reserve a car to show up at your house at that
time and place. It takes you to your destination then shoots off to an
electric or hydrogen-based fleet of these cars standing by at charging
facilities in neighborhoods and cities all over the world. If they became
ubiquitous enough you could have as little as a five to fifteen minute wait
for a car.

However, I think the auto industry would fight like hell to keep this kind of
system off the roads as it would severely dent auto sales. I mean hell, I know
I wouldn't want a car if I could just have a subscription to a car. Especially
if it wasn't just like Sedans. Imagine being able to rent a truck immediately
at a moment's notice, then ride back home in a Sedan, all without having to
worry about driving anywhere?

That's a world I would like to live in. Then once populations reached the
5,000+ ppl/km2 we could start building mag lev rails and get more into that
kind of public transportation.

~~~
stretchwithme
I think a lot of that will happen.

But what technologies power the vehicles or enable the roads are secondary.
The efficiencies gained by reducing vehicle size will slash costs.

A great many people will commute in a single seat vehicle with 50 horsepower
if its a quarter of the cost per mile. Especially if they aren't stuck with it
the rest of the time. As long as they can just as easily get larger vehicles
for other occasions.

As far as alternatives to conventional roads, we already have them in major
cities. Some are elevated and some are underground. Today only mass transit
uses them, but I fully expect robotic cabs to destroy mass transit. Even
people who don't value convenience will ultimately go for them. So subways and
elevated railways, once abandoned by trains, will be converted so they can be
used by individual vehicles.

~~~
seanp2k2
I disagree. See "one lane road" problem. Throughput will be very low and
average speeds for urban areas will be close to that of bikes, at best, unless
you're doing on/off ramps.

Also, re: many smaller cars... who will purchase/maintain all those? We don't
have the infrastructure to support that on many levels.

Personally, I think a system like that in /I, Robot/ is much more likely.

~~~
stretchwithme
People will operate businesses that own their own cabs or individuals their
own personal vehicles. Just as we do now.

And the infrastructure we have now will continue to operate.

How will such an infrastructure be built and be operated. Its a mystery. But
its already been done by private enterprise.

As to why only one slow lane could be used, I don't see why that would be.
Perhaps you could explain. We have many lanes operating now and robotic
vehicles would simply use the same lanes.

Perhaps PRT has these limitations. Robotic vehicles that operate like the
vehicles that operate like the vehicles we already have wouldn't.

Of course, we do not yet have robotic vehicles that can be trusted to operate
in rain or other extreme conditions and that can discern their environment
well enough to be safe.

But once we, there's no reason to follow the PRT pattern. We'll simply follow
the patterns we already have. Only with much more sharing (cabs) and much more
efficiency.

------
nkoren
This is already happening in the real world, driven by a number of companies
which the author does not mention:

<http://www.ultraglobalprt.com/> <http://www.2getthere.eu/>
<http://www.vectusprt.com/>

There is currently a system operating at Heathrow Airport; another at a campus
in Abu Dahbi; and a third under construction at a national park in South
Korea. Additional small systems are in the planning stages for a few more
cities / institutions around the world.

Skimming the article (unfortunately I don't have time to read it in depth), it
appears that the author has basically reinvented <http://www.skytran.net/> \--
a conceptual PRT system which has been kicking around for at least a decade
and a half. Real-world PRT systems tend to be considerably more modest in
their ambitions, following the "find a tiny niche" strategy of classic
disruptive technologies (in the Christensen sense of the term), rather than
trying to immediately become the be-all end-all of urban transport
infrastructure.

Also, skimming the article, it appears that the author makes a number of quite
silly mistakes -- curiously, the exact same mistakes that the Skytran people
do -- concerning the dynamics and requirements of urban transport. For
example, assuming a mean speed of 45 mph for existing transport is grossly
wrong: it ranges from about 35 mph to well under 20 mph for more congested
cities. (Here in London, it's 16mph -- a number which hasn't changed for over
a century). This has some profound implications for how fast you need to go to
provide a highly effective alternative, and correspondingly what your grid
sizes, turning radii, etc. should be. It looks like the author gets all of
this wrong, starting from a few bad assumptions.

Disclaimer: I used to work for Ultra PRT, and currently work for a large
transport/planning consultancy, advising on PRT installations around the
world.

------
bbhacker
For everyone who has not read it: Aaron is not proposing the future of ground-
based transportation. This is an analysis why he scraps his plans for a
magnet-levitation, personal transportation system and a call for new ideas.

~~~
tryitnow
To clarify, there is an urban density limit on this conclusion: "Time to get
to a station (walking, or drive plus park) kills the effectiveness of most
personal rapid transit and light-rail systems until you have a population
density of 5000+ ppl/km2."

So for population densities of 5,000+ ppl/km2 this might work (emphasis on
might).

Interestingly, urban areas of the developing world might qualify:

[http://www.citymayors.com/statistics/largest-cities-
density-...](http://www.citymayors.com/statistics/largest-cities-
density-125.html)

The problem is that many of these cities might not maintain their high
densities as their economies grow. My guess is that a lot of the high density
is due to extended families living together. But maybe not, there are quite a
few developed world cities on the list (e.g. London, Madrid, Seoul, Tokyo).

Unfortunately, I cannot vouch for the reliability of the statistics presented
here, there just a result of a very quick google search. I've got to stop
spending so much time on HN.

~~~
brc
The overall trend worldwide is toward higher urban density, not less. This is
more so in the developing countries - it's unlikely to swing away from this.
As long as population is growing, the cities tend to grow (and become more
dense) with them.

~~~
natrius
That is correct in the aggregate: people are moving from sparse rural areas to
denser metropolitan areas. However, the urban density of metropolitan areas
themselves is decreasing in the developed world. Most of the growth occurs in
relatively sparse suburbs.

------
slyall
The obvious problem seems to be that he wants a 200km/h speed which causes
problems on corners and for getting vehicles into the traffic stream.

This is causing a doubling of his costs which wrecks the business model.

However even a 50 km/h speed ( remember no stopping at lights or for jams ) is
going to be good-enough for many urban areas ( perhaps amining higher between
suburbs ) so he can bring his cost back down.

The ULTra system ( <http://en.wikipedia.org/wiki/ULTra_%28rapid_transit%29> )
currently has a maximum speed of just 40km/h although they are working on
faster speeds and reduced spacing between cars.

~~~
chipsy
Yes, I noticed that assumption too, and a few others(for example the
assumption of "car parked outside home" - now you have to value either the
cost of car ownership and parking, or the time cost for an on-demand fleet to
reach the passenger) With a lower speed target the system may still offer
benefits over roads and mass transit in terms of reliability/availability. The
number of existing PRT companies continuing with this approach suggests it has
some merit.

Maglev PRT still seems worth researching for intercity traffic though - the
requirements for routing get a lot easier, and you still have benefits of
speed and lightness.

------
melling
How about bicycles? I live 4.2 miles from my NYC office and it takes me 45
minutes to walk/bus/walk. On bad days, it can be 90 minutes. The congestion in
the NYC tunnels and in the bus station during rush hour is unbearable. Let me
grab my bicycle and a place to store it during the day and I'll use it 10
months out of the year.

~~~
rdouble
I bought a Brompton folding bicycle in NYC. It's great. Very easy to bring on
the subway, ferry or even a taxi.

The only downside is the small diameter of the wheels makes climbing a bit
comedic.

~~~
T-hawk
I have a Strida folding bike for commuting in NYC by ferry and subway too.
Love it.

Wheel diameter doesn't matter for climbing, though. Bigger wheels are more
efficient on a flat surface by way of less rolling resistance; the bigger
wheel creates a smoother tangent with the road surface, and contains more air
so deforms less under its weight load. But when you're climbing, rolling
resistance means almost nothing compared to the energy you need to supply to
climb the well of gravitation potential.

The problem with climbing on a folding bike is frame rigidity. The geometry
required by most folders (long single tubes connected by joints with necessary
slop for folding) means that a fair bit of the energy you supply goes into
stressing and flexing the frame rather than transmitting into the drive
system. The traditional brazed diamond frame doesn't have that problem. To
make an extreme metaphor, climbing on a folder is a bit like pushing a string,
where the energy goes into deforming the nonrigid body instead of moving it.

If wheel diameter mattered for climbing, then either skateboards couldn't
climb hills or they'd have bigger wheels for doing so.

------
pat2man
The problem with a system like this is that it requires us to throw out the
existing system and replace it. This is unlikely to happen.

I would assume that a more realistic system would to drastically expand our
existing light rail, subway etc systems and fix the last mile issue with
automated taxi cabs.

Automated cars have the advantage of using our existing road system without
the existing issues of storage and accidents.

Combining them with an efficient mass transit "core" we could achieve all the
above goals with minimal changes to our existing infrastructure.

~~~
beefman
I guess you didn't read the article:

""We live in a world designed around cars. Because world population has grown
five-fold during the age of cars, we will be stuck with their legacy in roads
and low-density metro configurations for at least the next century. This
realization is a difficult one. I set out to start a company that could
radically transform transportation. But neither the physics nor economics work
out, and in fact will not work out until population density is much higher.

It is the ubiquity of roads, more than the greatness of cars that is difficult
to defeat. And so, the future of transportation is, perhaps disappointingly,
simply better cars. Our abstract criterion for the perfect transportation
system is one that is fast, ubiquitous, has on-demand departure, and is quiet,
private, and safe. The solution to all of these is a self-driving car.

It is clear that a maglev based personal rapid transit elevated track system
should not be pursued as a business.""

~~~
brc
Cars didn't invent the road, certainly not the city-based road, anyway.

Most of the worlds largest cities were designed and laid out long before a car
was ever even dreamed of.

Roads, laneways and streets are a feature of every single ancient
civilization. Mass transit is good at being mass transit, but personalised
transportation (whether foot, bicycle, animal or vehicle) is always going to
be with us.

Of course the future is cars for the majority of people, because the majority
want personalised transport where mass transit is incapable of bridging the
gap.

------
wjessup
The reasoning and analysis is so silly I would question all of the thinking
that went into this article:

“The real problem with PRT in dense urban areas is parking. During non-rush
hour periods, what do you do with 333k vehicles?”

What a huge face-palm.

This refers to his statement about NY where he naively assumed the most
sensible analysis was one that replaced the existing subway completely with
PRT. \- Then, magically, every person would go buy a car ( why? ) \- All those
people would need parking spots at the PRT stations that are within minutes
walking distance \- He designed a one-size-fits-all solution instead of
recognizing that a combination of several specialized solutions is even
possible.

You're not going to replace the ultimate freedom cars give you, nor the huge
capacity the subway provides. PRT does something else - it provides a
supplemental point-to-point transportation.

Also, the peak demand measurement is flawed because it is based on existing
infrastructure. X cars go on a freeway / hour. Y people go on a subway / hour.
But you are forced to use the 10 freeway because its the only infrastructure
that provides for MANY routes [ santa monica - downtown ], [ culver city -
hollywood ] and so on. Considering the "mesh" feature of PRT requires an
analysis instead of starting and ending destinations - not the infrastructure
those trips used!

------
chrismealy
Good lord, just making bicycling safe for everyone and there's your magic
bullet.

------
jwatte
Cost of asphalt is going up significantly! Even with electric cars, cost of
oil may end up making track based systems more effective.Also, what is the
maintenance cost of a road. Vs a track? And what about reclaiming all the land
on the ground, and land used for parking? In some areas, that will more than
pay for the system!

~~~
protomyth
Given the upwards cost, and this sounds dumb, but I was kinda hoping for a
revolution in bricks for roads. The brick laying machine out of Europe combine
with some embedded RFID chip in each brick (perhaps with a different code for
the road edge and turning lane bricks) might make for an interesting
experiment.

------
stretchwithme
I don't think PRT will win. The next transportation revolution will not
require duplicating the infrastructure we already have.

I used to be enamored with PRT. It seems so logical.

And it might win if you designing a city from scratch and could layout
everything to minimize the inconveniences inherent to a fixed track system.

But has it even been implemented in such a new community? No, usually people
in even a new community have a strange need to go to other places. There's a
system that already works for that. So they simply extend that system a little
further and gain access to all of its advantages.

The next revolution in transportation will take advantage of this existing
network.

~~~
ricardobeat
They tried (and failed) in Masdar - UAE:
[http://singularityhub.com/2011/03/01/masdar-city-abandons-
pu...](http://singularityhub.com/2011/03/01/masdar-city-abandons-public-
transportation-system-of-the-future/)

And I think you didn't read the article. It gets to exactly the same
conclusion you did - or are you just trying to be witty? :)

~~~
stretchwithme
Interesting. Hadn't read it, but the basic idea has been tried many times.

------
FrojoS
I have to confess, that links and discussion like this are my secret number
one reason to visit HN regularly.

By reading the comments on swiftprt.com I also found the interesting project
of electric airplane takeoff <http://electrictakeoff.com/>

Is there an online community that discusses such questions more frequently?

------
brianbreslin
i remember seeing an example simulation 6 months ago out of europe where they
were using high speed rail with feeder cars that would pull up alongside the
main fast train to let people on/off, without slowing down the main train.
this was thought up to speed train travel as the acceleration/deceleration of
maglev trains contribute to their energy and time delays.

------
seanp2k2
I see this idea as fundamentally flawed in that it's trying to do 2-person
cars. After I read that, none of the ensuing calculations mattered at all. We
need to work around the train schedules, not try to work them around our
schedules. Look at downtown SF. Mass transit there is AMAZING. Muni stations
are every few /blocks/.

Also, why choose below-the-rail? Requires stronger towers, can't turn as fast
as existing rail, etc. This was a silly decision IMO. I think these guys need
to work with roller coaster engineers if they can only do /10kmph/ around
curves.

Yet another still-born mass transit idea. Can we please just get the Cali
high-speed rail done already to prove to the rest of USA something that other
countries know already? High speed rail works great and can indeed "work"
economically.

------
jakozaur
In fact there are people, who are trying to implement similar system:
<http://www.mist-er.com/> It is not MagLev, but the basic idea is same.

------
gfodor
It's seems like the "getting to the station takes ten minutes" problem is
easily solved with things like the Segway, if people could be expected to
actually ride them.

~~~
ScottBurson
Since I sometimes commute by Caltrain, I have been very interested in this
"last mile or two" transportation problem.

A remarkable number of engineer/entrepreneurs have sprung up attempting to
offer devices that solve it. Here are some highlights of what I've found:

Segway: easy to ride and reasonably fast, but expensive, and worse, _much_ too
heavy (100 lb) to pick up and take on a train.

YikeBike folding electric bicycle: looks not too hard to ride; a little slow,
perhaps, at 15 mph. A technological marvel (anti-lock brakes!) but
correspondingly expensive ($2000 for the 31 lb model, $3800 for the 24 lb
carbon fiber model).

Conscious Commuter folding electric bicycle: this is a very nice-looking
design whose development was recently funded on Kickstarter
([http://www.kickstarter.com/projects/1585753369/folding-
elect...](http://www.kickstarter.com/projects/1585753369/folding-electric-
bike-for-commuters)). No specs yet, but looks extremely promising.

Trikke EV: a very creative design. Looks fun to ride, but a little heavy for
this purpose (38 - 46 lb depending on model) and not particularly fast (13 -
16 mph).

Metroboard electric skateboard: reasonably fast (20 mph) and extremely light
(~20 lbs depending on model). I have one of these and it's an impressive piece
of engineering and fun to ride, but it does require substantial athleticism
and, uh, a certain risk tolerance. Not a mass market product.

If those aren't exotic enough for you, a number of people are working on self-
balancing electric unicycles (!!).

~~~
ams6110
If we're talking about a "last mile or two" what's wrong with a conventional
bicycle? These other things seem to be needlessly expensive and complex
solutions to that problem.

The big problem with all of these though is they are all unpleasant in
inclement weather and cold temperatures.

~~~
ScottBurson
Conventional bicycles are bulkier than these other solutions, making them
harder to carry onto whatever mass transit one is using. On Caltrain, for
example, bicycles are restricted to a special car at one end of the train. On
other systems like BART, bicycles aren't even allowed on many trains.

The other problem with conventional bicycles is that it's hard to go very far
without getting sweaty -- depending on the weather, of course, and one's
patience for riding slowly. It's nice to have power assist.

Folding bicycles can be compact enough to carry on any mass transit
conveyance. The Metroboard is certainly quite compact and portable. Not sure
about the Trikke.

You're right that weather can be a problem.

~~~
pak
I'd get a cheapo used bike and lock it at the station. Bike racks/poles are
everywhere; personally, I think people carrying their Inspector Gadget $2000
foldabikes on the train are overestimating the utility of taking the same bike
everywhere. As for getting sweaty, this is just the last mile we're talking
about--if you get worked up on a 10 minute bike ride it's time for more
exercise!

------
toisanji
Aaron, why don't you work on self-driving cars?

