On 5 Sep, 20:09, JNugent
noparticularplacetogo.com> wrote:> goo...@woodall.me.uk wrote:
>> "John Rowland"
journeyflow.spamspam.demon.co.uk> wrote:>>> Tom Anderson wrote:
>>> 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.
