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, 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.

On Fri, 05 Sep 2008 20:09:52 +0100, JNugent
wrote:

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 people that do think that you can build your way out of congestion
should stop for a moment and ask themselves if the M25 does work at
8am on a rainy Monday morning in December.

Prior to the M25 hardly anyone would have considered living one side
of London and working the other. Now the M25 exists people do.

People will put up with a certain level of 'crapness' in a journey. If
it is too crap then they either won't start doing it or will stop
doing it.

The M1 is being expanded into 4 lanes into London, will that solve the
congestion problems on that road? It would if only the vehicles that
currently use it, use it in the future. But as the road will become
less crap when the 4 lanes open, then more people will start using the
M1, until it degenerates again into the current level of crapness. So
you may get a small window of improvement, but it fixes nothing over
time.

JB wrote:

JNugent wrote:

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 people that do think that you can build your way out of congestion
should stop for a moment and ask themselves if the M25 does work at
8am on a rainy Monday morning in December.

Compared to the alternative(s), of course it does, both for the traffic
travelling on it and for the roads it relieves (Dorking, anyone?).

Prior to the M25 hardly anyone would have considered living one side
of London and working the other. Now the M25 exists people do.

People keep saying this, and it is possible that there are a few examples,
but by and large, the same quantification ("hardly anyone") applies both
before and after the construction of the M25. Living in Kingston and working
in Brentwood is not new.

People will put up with a certain level of 'crapness' in a journey. If
it is too crap then they either won't start doing it or will stop
doing it.

And?

The M1 is being expanded into 4 lanes into London, will that solve the
congestion problems on that road? It would if only the vehicles that
currently use it, use it in the future. But as the road will become
less crap when the 4 lanes open, then more people will start using the
M1, until it degenerates again into the current level of crapness. So
you may get a small window of improvement, but it fixes nothing over
time.

If you were right about that (you aren't), every town and village along the
line of the routes superseded by the motorway network (cf: Holmes Chapel, or
Talke Pits, or Stone) would be as congested today as they were in the summer
of 1958. They aren't.

Similarly, if you were right about that (you aren't), it would still take 12
hours to drive from (say) Preston to London. It doesn't, except in unusual
conditions where a road is closed due to an accident or incident trapping
traffic on a motorway with no means of escape until the incident is cleared.
I'll admit that one good thing about the A50 was that you could abandon your
journey, do a three-pointer and go home.

In message , at 09:39:10 on
Sun, 14 Sep 2008, JB remarked:
And people that do think that you can build your way out of congestion
should stop for a moment and ask themselves if the M25 does work at
8am on a rainy Monday morning in December.

Just because it has problems at specific times and location doesn't mean
that overall it's not an improvement. As someone who weekly-commuted
between Essex and Reading, even a congested M25 beats what was there
before.
--
Roland Perry

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.