Science:

http://arstechnica.com/news.ars/post...f-anarchy.html

I look forward to reading the paper, and to following development of these
ideas in the future.

tom

--
All London roads are part of MY London Cycle Network. I'd like to see
some of them removed from the London Motor Network! -- Ben Jefferys

Tom Anderson wrote:
Science:

http://arstechnica.com/news.ars/post...f-anarchy.html

I look forward to reading the paper, and to following development of
these ideas in the future.

Obviously if every side road off your commute between your home and your
office was closed, this would speed up your journey. Unless you're Kim
Jong-il, I don't see that as useful info.

On Sep 5, 2:52 pm, "John Rowland"
wrote:
Tom Anderson wrote:
Science:

http://arstechnica.com/news.ars/post...riving-causes-...

I look forward to reading the paper, and to following development of
these ideas in the future.

Obviously if every side road off your commute between your home and your
office was closed, this would speed up your journey. Unless you're Kim
Jong-il, I don't see that as useful info.

But that's not what's being claimed. What is being claimed is that by
closing certain links, journey time for everybody can be improved.

This isn't particularly new. However, I'm not sure anybody has
actually tried to predict which roads should be closed to improve
congestion. The wiki page: http://en.wikipedia.org/wiki/Braess%27_paradox
gives a couple of examples where a new road increased congestion and
closing it relieved the congestion again. It also gives the example of
the closing of 42nd street in NYC reducing congestion - however I
don't know if that was luck or planning.

Note that this is different from the claim that new roads cause extra
traffic. This is the case when, everything else staying equal, opening
a new, fast, road can cause all the existing people to see increased
journey times without adding any new journeys.

Tim.

wrote:

"John Rowland" wrote:
Tom Anderson wrote:

Science:

http://arstechnica.com/news.ars/post...riving-causes-...

I look forward to reading the paper, and to following development of
these ideas in the future.

Obviously if every side road off your commute between your home and your
office was closed, this would speed up your journey. Unless you're Kim
Jong-il, I don't see that as useful info.

But that's not what's being claimed. What is being claimed is that by
closing certain links, journey time for everybody can be improved.

Indeed. It looks like good, well-informed and useful research.

Certain road schemes in the UK have actually been built with the same sort of
consideration in mind - and that's going back over four decades. The
best-known example may well be the M6/A452 junction at Castle Bromwich (then
in Warwickshire), opened to traffic in 1971. The junction:

http://maps.google.co.uk/?ie=UTF8&ll=52.509339,-1.792595&spn=0.009899,0.019312&z=16

.... has slip roads which face only to the east, a move designed to prevent
commuting along the M6 from Castle Bromwich to the A38(M) at Gravelly Hill
and thence to Birmingham City Centre.

This isn't particularly new.

Precisely. But there is always room for proper theoretical and empirical
research in order to test what is often thought of as "common sense".

Perhaps, eventually, some of those junctions along the northern edge of the
M25 (J26 A121, anyone?) will be shut (except for emergency access and egress)
in order to prevent traffic being slowed by rush-hour joiners. I'm fairly
sure that the M25 was never meant to facilitate access to Waltham Abbey in
any event.

However, I'm not sure anybody has
actually tried to predict which roads should be closed to improve
congestion. The wiki page: http://en.wikipedia.org/wiki/Braess%27_paradox
gives a couple of examples where a new road increased congestion and
closing it relieved the congestion again. It also gives the example of
the closing of 42nd street in NYC reducing congestion - however I
don't know if that was luck or planning.

Note that this is different from the claim that new roads cause extra
traffic. This is the case when, everything else staying equal, opening
a new, fast, road can cause all the existing people to see increased
journey times without adding any new journeys.

Again, this is an obvious point. Those who claim that you can't build your
way out of congestion should stop for a moment and ask themselves what would
happen in London if the M25 (including the Dartford Crossing) was closed to
traffic.

And then they should ask themselves whether bilding/re-opening the M25 (they
amount to the same thing) would relieve congestion or not.

On 5 Sep, 12:26, Tom Anderson wrote:
Science:

http://arstechnica.com/news.ars/post...riving-causes-...

I look forward to reading the paper, and to following development of these
ideas in the future.

The source says:

"Uncoordinated individuals in human society pursuing their personally
optimal strategies do not always achieve the social optimum, the most
beneficial state to the society as a whole. Instead, strategies form
Nash equilibria which are often socially suboptimal. Society,
therefore, has to pay a price of anarchy for the lack of coordination
among its members."

Or in other words, selfish drivers do not serve the common good and
give anarchists a bad name. Well, we knew that already didn't we.

--
World Carfree Network
http://www.worldcarfree.net/
Help for your car-addicted friends in the U.K.

On 5 Sep, 20:09, JNugent wrote:
wrote:
"John Rowland" wrote:
Tom Anderson wrote:
Science:
http://arstechnica.com/news.ars/post...riving-causes-...
I look forward to reading the paper, and to following development of
these ideas in the future.
Obviously if every side road off your commute between your home and your
office was closed, this would speed up your journey. Unless you're Kim
Jong-il, I don't see that as useful info.
But that's not what's being claimed. What is being claimed is that by
closing certain links, journey time for everybody can be improved.

Indeed. It looks like good, well-informed and useful research.

Certain road schemes in the UK have actually been built with the same sort of
consideration in mind - and that's going back over four decades. The
best-known example may well be the M6/A452 junction at Castle Bromwich (then
in Warwickshire), opened to traffic in 1971. The junction:

http://maps.google.co.uk/?ie=UTF8&ll=52.509339,-1.792595&spn=0.009899...

... has slip roads which face only to the east, a move designed to prevent
commuting along the M6 from Castle Bromwich to the A38(M) at Gravelly Hill
and thence to Birmingham City Centre.

This isn't particularly new.

Precisely. But there is always room for proper theoretical and empirical
research in order to test what is often thought of as "common sense".

Perhaps, eventually, some of those junctions along the northern edge of the
M25 (J26 A121, anyone?) will be shut (except for emergency access and egress)
in order to prevent traffic being slowed by rush-hour joiners. I'm fairly
sure that the M25 was never meant to facilitate access to Waltham Abbey in
any event.

However, I'm not sure anybody has
actually tried to predict which roads should be closed to improve
congestion. The wiki page:http://en.wikipedia.org/wiki/Braess%27_paradox
gives a couple of examples where a new road increased congestion and
closing it relieved the congestion again. It also gives the example of
the closing of 42nd street in NYC reducing congestion - however I
don't know if that was luck or planning.
Note that this is different from the claim that new roads cause extra
traffic. This is the case when, everything else staying equal, opening
a new, fast, road can cause all the existing people to see increased
journey times without adding any new journeys.

Again, this is an obvious point. Those who claim that you can't build your
way out of congestion should stop for a moment and ask themselves what would
happen in London if the M25 (including the Dartford Crossing) was closed to
traffic.

And then they should ask themselves whether bilding/re-opening the M25 (they
amount to the same thing) would relieve congestion or not.

Closing the M25 would cause massive congestion which in turn would
reduce traffic journeys. After a period of adjustment it is likely
that more people would leave their cars at home and a state of
equilibrium would finally be reached again, but with less traffic.
What you have to realise is that there is a high proportion of non-
essential journeys made which are actively encouraged by perpetual
roadbuilding and these impede essential journeys, such as food
deliveries.

Some means has to be found of combating the anti-social and anti-
environmental habits of many motorists, instead of always giving in to
their unreasonable consumerist demands.

--
World Carfree Network
http://www.worldcarfree.net/
Help for your car-addicted friends in the U.K.

Doug wrote:
On 5 Sep, 20:09, JNugent wrote:
wrote:
"John Rowland" wrote:
Tom Anderson wrote:
Science:
http://arstechnica.com/news.ars/post...riving-causes-...
I look forward to reading the paper, and to following development of
these ideas in the future.
Obviously if every side road off your commute between your home and your
office was closed, this would speed up your journey. Unless you're Kim
Jong-il, I don't see that as useful info.
But that's not what's being claimed. What is being claimed is that by
closing certain links, journey time for everybody can be improved.
Indeed. It looks like good, well-informed and useful research.

Certain road schemes in the UK have actually been built with the same sort of
consideration in mind - and that's going back over four decades. The
best-known example may well be the M6/A452 junction at Castle Bromwich (then
in Warwickshire), opened to traffic in 1971. The junction:

http://maps.google.co.uk/?ie=UTF8&ll=52.509339,-1.792595&spn=0.009899...

... has slip roads which face only to the east, a move designed to prevent
commuting along the M6 from Castle Bromwich to the A38(M) at Gravelly Hill
and thence to Birmingham City Centre.

This isn't particularly new.
Precisely. But there is always room for proper theoretical and empirical
research in order to test what is often thought of as "common sense".

Perhaps, eventually, some of those junctions along the northern edge of the
M25 (J26 A121, anyone?) will be shut (except for emergency access and egress)
in order to prevent traffic being slowed by rush-hour joiners. I'm fairly
sure that the M25 was never meant to facilitate access to Waltham Abbey in
any event.

However, I'm not sure anybody has
actually tried to predict which roads should be closed to improve
congestion. The wiki page:http://en.wikipedia.org/wiki/Braess%27_paradox
gives a couple of examples where a new road increased congestion and
closing it relieved the congestion again. It also gives the example of
the closing of 42nd street in NYC reducing congestion - however I
don't know if that was luck or planning.
Note that this is different from the claim that new roads cause extra
traffic. This is the case when, everything else staying equal, opening
a new, fast, road can cause all the existing people to see increased
journey times without adding any new journeys.
Again, this is an obvious point. Those who claim that you can't build your
way out of congestion should stop for a moment and ask themselves what would
happen in London if the M25 (including the Dartford Crossing) was closed to
traffic.

And then they should ask themselves whether bilding/re-opening the M25 (they
amount to the same thing) would relieve congestion or not.

Closing the M25 would cause massive congestion which in turn would
reduce traffic journeys. After a period of adjustment it is likely
that more people would leave their cars at home and a state of
equilibrium would finally be reached again, but with less traffic.
What you have to realise is that there is a high proportion of non-
essential journeys made which are actively encouraged by perpetual
roadbuilding and these impede essential journeys, such as food
deliveries.

Some means has to be found of combating the anti-social and anti-
environmental habits of many motorists, instead of always giving in to
their unreasonable consumerist demands.

--
World Carfree Network
http://www.worldcarfree.net/
Help for your car-addicted friends in the U.K.


But thousands of people would be unable to get to work, would not get
paid and would consequently not pay any tax. That would mean that *your*
State cream-off would be seriously at risk.

--
Moving things in still pictures!

Doug wrote:
Closing the M25 would cause massive congestion which in turn would
reduce traffic journeys. After a period of adjustment it is likely
that more people would leave their cars at home and a state of
equilibrium would finally be reached again, but with less traffic.
What you have to realise is that there is a high proportion of non-
essential journeys made which are actively encouraged by perpetual
roadbuilding and these impede essential journeys, such as food
deliveries.

There seems to be a new phrase we can add to the list of Dougisms,
"perpetual roadbuilding".

(Dougism = a word, term or phrase previously shown to be wrong in fact.)

Some means has to be found of combating the anti-social and anti-
environmental habits of many motorists, instead of always giving in to
their unreasonable consumerist demands.

So what would your solution be Doug? Starting from the basis that people
are, by their very nature, consumers.

Doug wrote:
On 5 Sep, 12:26, Tom Anderson wrote:
Science:

http://arstechnica.com/news.ars/post...riving-causes-...

I look forward to reading the paper, and to following development of
these ideas in the future.

The source says:

"Uncoordinated individuals in human society pursuing their personally
optimal strategies do not always achieve the social optimum, the most
beneficial state to the society as a whole. Instead, strategies form
Nash equilibria which are often socially suboptimal. Society,
therefore, has to pay a price of anarchy for the lack of coordination
among its members."

Or in other words, selfish drivers do not serve the common good and
give anarchists a bad name. Well, we knew that already didn't we.

No Doug, people behave like that whether they are drivers or not. Anarchists
are by nature selfish.

wrote:
On Sep 5, 2:52 pm, "John Rowland"
wrote:
Tom Anderson wrote:
Science:
http://arstechnica.com/news.ars/post...riving-causes-...
I look forward to reading the paper, and to following development of
these ideas in the future.
Obviously if every side road off your commute between your home and your
office was closed, this would speed up your journey. ...
But that's not what's being claimed. What is being claimed is that by
closing certain links, journey time for everybody can be improved.

Assuming:-
- that 'everybody' includes only motorised road users
- that those whose journeys are lengthened drive faster to compensate

And it's been happening for years, with the twin aims of getting motor
traffic onto the main corridors and keeping it moving there.

The result is a much less permeable network, with increased journey
distance, increased free-flowing traffic speeds, reduced lane widths,
and kerbside barriers everywhere.

It's hard to see how they could have done any more to discourage
cycling, and it's nearly as bad for pedestrians.

Colin McKenzie

--
No-one has ever proved that cycle helmets make cycling any safer at the
population level, and anyway cycling is about as safe per mile as walking.
Make an informed choice - visit www.cyclehelmets.org.