LTN: Our Healthy Streets - Dulwich: Phase 3

[slarti b]

Exdulwicher, you are avoiding my question!!!

Displacement and evaporation are closely linked. In your example, if route A is blocked some of the traffic may evaporate but the rest will be displaced onto Route B (or C etc).

The Council's presentation for OHS essentially said, dont worry about the displacement effect on the main roads because traffic will evaporate. But this is contradicted by their own figures.

So, I repeat the question, which roads will the traffic displaced from Dulwich Village (less some evaportation) use for their journeys?

[JohnL]

if there's huge queues on the main roads due to displacement then more traffic will evaporate as people give up and try to find other ways of doing things.

Surely that's the plan.

[dulwichfolk]

The problem with this is due to covid the alternatives (public transport) do not exist so lots will just sit it out...

[Bicknell]

its the kids I feel sorry for. we're pushing traffic from here to there, and theyre walknig past traffic jams breathing in all the pollution

[Rockets]

exdulwicher Wrote:

-------------------------------------------------------

> You're conflating displacement (where the same

> amount of traffic is moved from Route A to Route

> B) and evaporation (where some vehicle journeys

> previously made on the now inaccessible Route A

> are made by alternative means - the active travel

> plans obviously focus on cycling and walking but

> it could also be car-sharing, public transport or

> simply that people change their habits - for

> example only driving to the shops once a week

> rather than three times).

>

> Hammersmith Bridge is quite a good example, it's

> been closed long enough to have some reasonably in

> depth assessment done on surrounding traffic and

> pollution levels.

>

> https://www.hammersmithbridge.org.uk/p/179/traffic

> -evaporation

> https://www.citymetric.com/horizons/has-closing-ha

> mmersmith-bridge-really-improved-london-s-air-qual

> ity-4731

>

> There's a PDF of a metadata study on the subject

> here which, although rather wordy, also manages to

> keep the maths to a minimum.

> https://www.hammersmithbridge.org.uk/Uploads/2019-

> 05-23-5343-Disappearing%20traffic%20-%20the%20stor

> y%20so%20far.pdf

>

> There's a reasonable chunk of data and info from

> places like Hackney and Waltham Forest which have

> had similar measures (back when the popular term

> was Mini-Holland) for a lot longer than Dulwich as

> well.

Yes and for those who live on the route to Hammersmith bridge they have seen a huge decrease in traffic but speak to those living near the neighbouring bridges and they will tell you an altogether different story....

Exdulwicher - what is a realistic figure for evaporation in situations like we are seeing in Dulwich. My feeling is that of you're lucky to might get 10% of people switching (during summer months).

[exdulwicher]

From page 4 of the pdf I linked to earlier:

"The mean average was a reduction of 21?9% and the median ? which is a better measure of central tendency here, given the variability of results ? was a reduction of 10?6%.

In other words, in half the cases, over 11% of the vehicles which were previously using the road or the area where

roadspace for general traffic was reduced, could not be found in the surrounding area afterwards."

That's from a collation of 60 high quality studies (the pdf references 100 but when analysing them, 40 were not of suitably high quality or not long-term enough). Further info and details in the pdf.

It can be quite heavily dependent on the area, the measures imposed, the ratio of population with / without cars and so on but the figures are broadly comparable worldwide indicating that weather is not really a factor.

The problem with this is due to covid the alternatives (public transport) do not exist so lots will just sit it out...

That is the current elephant in the room. Trains are back up to about 30% of pre-Covid levels now which is beginning to make social distancing a problem on some services. However the pattern of use has changed - the morning rush is more spread out and (because it's summer holidays, because a lot of offices are not fully open) some of the issues are on services down to the coast - basically people going to the beach for a day out. Buses are still a bit of an unknown quantity - TfL was reckoning about 20% of pre-Covid levels of use overall but that's offset by a significant drop in usage in the city as there are far fewer people there at the moment. That said, it does exist as an option - I've used ND to London Bridge a few times and the 176, 40 and 185 services with no issues. In fact public transport at the moment is as good as it's ever going to get. Far fewer passengers, no queues, no standing and, because there are fewer people the level of service (in terms of on-time) is excellent. :-)

[slarti b]

exdulwicher Wrote:

-------------------------------------------------------

> From page 4 of the pdf I linked to earlier:

>

> "The mean average was a reduction of 21?9% and the median ? which is a better measure of central

> tendency here, given the variability of results was a reduction of 10?6%.

Goodwins statistical methodology appear highly questionable. Was the original paper peer reviewed by a statistican?

Also, can you please, please answer my question about which roads the trafiic displaced\ reallocated from Dulwich Village will use?

[andrewc]

Are there any studies that show that 'overall' traffic reduction does not happen as a result of road closures?

Or, contrariwise, that adding roads to a network reduces road use?

[Rockets]

exdulwicher Wrote:

-------------------------------------------------------

> From page 4 of the pdf I linked to earlier:

>

> "The mean average was a reduction of 21?9% and the

> median ? which is a better measure of central

> tendency here, given the variability of results ?

> was a reduction of 10?6%.

> In other words, in half the cases, over 11% of the

> vehicles which were previously using the road or

> the area where

> roadspace for general traffic was reduced, could

> not be found in the surrounding area afterwards."

>

> That's from a collation of 60 high quality studies

> (the pdf references 100 but when analysing them,

> 40 were not of suitably high quality or not

> long-term enough). Further info and details in the

> pdf.

>

> It can be quite heavily dependent on the area, the

> measures imposed, the ratio of population with /

> without cars and so on but the figures are broadly

> comparable worldwide indicating that weather is

> not really a factor.

>

> The problem with this is due to covid the

> alternatives (public transport) do not exist so

> lots will just sit it out...

>

> That is the current elephant in the room. Trains

> are back up to about 30% of pre-Covid levels now

> which is beginning to make social distancing a

> problem on some services. However the pattern of

> use has changed - the morning rush is more spread

> out and (because it's summer holidays, because a

> lot of offices are not fully open) some of the

> issues are on services down to the coast -

> basically people going to the beach for a day out.

> Buses are still a bit of an unknown quantity - TfL

> was reckoning about 20% of pre-Covid levels of use

> overall but that's offset by a significant drop in

> usage in the city as there are far fewer people

> there at the moment. That said, it does exist as

> an option - I've used ND to London Bridge a few

> times and the 176, 40 and 185 services with no

> issues. In fact public transport at the moment is

> as good as it's ever going to get. Far fewer

> passengers, no queues, no standing and, because

> there are fewer people the level of service (in

> terms of on-time) is excellent. :-)

So my guess of about 10% wasn't wildly inaccurate...;-) Now let's flip it on it's head...can the surrounding roads absorb the 80% to 90% of increased traffic due to the closures? Does anyone ever model that into their plans?

If we are trying to achieve a 10% reduction then I suggest there are far less disruptive ways of doing it than the path our council, and others, are following and the fallout will be far more damaging. Trying to squeeze more water down the hosepipe of surrounding roads does not lead to evaporation...it leads to burst pipes...just look what happens when Thames Water deals with a pipe or water main leak, they fix it in one place and then 50 yards down the road a new leak appears and they just chase the leaks down the pipe because the infrastructure cannot take the increased pressure and something has to give.

Surely no-one, other than the most hardened pro-cycle headbanger can defend all this disruption and increase in pollution elsewhere for a 10% reduction in car use?

Cue responses from hardened pro-cycle headbangers...;-)

[andrewc]

Here is a the introduction to the study (Generated Traffic and Induced Travel) below.

Traffic engineers often compare traffic to a fluid, assuming that a certain volume must flow through the road system, but it is more appropriate to compare urban traffic to a gas that expands to fill available space (Jacobsen 1997). Traffic congestion tends to maintain equilibrium: traffic volumes increase to the point that congestion delays discourage additional peak-period vehicle trips. Expanding congested roads attracts latent demand, trips from other routes, times and modes, and encourage longer and more frequent travel. This is called generated traffic, referring to additional peak-period vehicle traffic on a particular road. This consists in part of induced travel, which refers to absolute increases in vehicle miles travel (VMT) compared with what would otherwise occur.

https://www.researchgate.net/publication/235360397_Generated_Traffic_and_Induced_Travel_Implications_for_Transport_Planning

[spider69]

Perhaps instead of using all these wonderful computer systems having someone stand on the side of the road and saying what if I screwed this flow up what would happen.

No doubt too simple, cannot waste UNi degrees that only come a book not life experiences.

[JohnL]

Rockets Wrote:

-------------------------------------------------------

> Surely no-one, other than the most hardened

> pro-cycle headbanger can defend all this

> disruption and increase in pollution elsewhere for

> a 10% reduction in car use?

>

> Cue responses from hardened pro-cycle

> headbangers...;-)

Notice how all the government ministers seem to cycle - from Boris down - however silly they look.

read Boris's meanderings

https://www.forbes.com/sites/carltonreid/2020/07/27/well-build-thousands-of-miles-of-protected-cycleways-pledges-boris-johnson/#37b8991f6b2c

'The bicycle, said Johnson, was a ?giant, universal prescription? and the new cycleways would become ?huge, 24-hour gyms, free and open to everyone.?'

[slarti b]

andrewc Wrote:

-------------------------------------------------------

> Here is a the introduction to the study (Generated Traffic and Induced Travel) below.

Andrew,

Can you answer the questions relating to the situation in Dulwich rather than psoting posting the same links to theoretical research? To remind you, the question is

"Nevertheless, even ignoring the many flaws in that study, the report's conclusion, is used by the council to suggest that 11% of the through traffic through Dulwich will evaporate. From the council's own figures that would leave over 6,300 daily movements diverted onto the "main roads", ie Lordship Lane, EDG, Half Moon Lane, South Circular Road and Croxted Road. That was one of the objectives of the OHS scheme that is now being implemented without consultation under the cover of Covid emergency regs. Do you think that is acceptable for those living or going to schools on those "Main roads"? xxx

[andrewc]

Are there any studies that support the case that a reduction in traffic of 11% in an area is a benefit to the whole community? Or does it just benefit those on the quieter roads. I don't know if improved air quality is shared among connecting streets.

[Abe_froeman]

In another nearby borough I discovered today the residents themselves have removed one of the new planters blocking their road because they were so fed of up all the new congestion caused by cars trying to find alternative routes and endlessly u turning.

The implementation and outcome of these schemes have been utterly woeful.

[exdulwicher]

spider69 Wrote:

-------------------------------------------------------

> Perhaps instead of using all these wonderful

> computer systems having someone stand on the

> side of the road and saying what if I screwed

> this flow up what would happen.

>

For similar sorts of reasons that the congestion charge is not handled by people standing at the side of the road with clipboards writing down number plates...

[slarti b]

exDulwicher, It looks like you don't want to answer my question about which roads the traffic displaced by the OHS scheme would end up using. Any reason why please?

[first mate]

Not in any way advocating or condoning this sort of action but would not be surprised if more of this occurs. When you read about break-ins and theft carried out in broad daylight with no police action, moving planters will probably be pretty low on the list.

Abe_froeman Wrote:

-------------------------------------------------------

> In another nearby borough I discovered today the

> residents themselves have removed one of the new

> planters blocking their road because they were so

> fed of up all the new congestion caused by cars

> trying to find alternative routes and endlessly u

> turning.

>

> The implementation and outcome of these schemes

> have been utterly woeful.

[thebestnameshavegone]

It's quite easy to replace them with concrete blocks as they've done on Rye Lane.

It's a bit futile, tearfully vandalising a planter because you want to drive your brum-brum wherever you please

first mate Wrote:

-------------------------------------------------------

> Not in any way advocating or condoning this sort

> of action but would not be surprised if more of

> this occurs. When you read about break-ins and

> theft carried out in broad daylight with no police

> action, moving planters will probably be pretty

> low on the list.

>

> Abe_froeman Wrote:

> --------------------------------------------------

> -----

> > In another nearby borough I discovered today

> the

> > residents themselves have removed one of the

> new

> > planters blocking their road because they were

> so

> > fed of up all the new congestion caused by cars

> > trying to find alternative routes and endlessly

> u

> > turning.

> >

> > The implementation and outcome of these schemes

> > have been utterly woeful.

[first mate]

In fairness, eD generally does answer questions and no doubt will this one.

slarti b Wrote:

-------------------------------------------------------

> exDulwicher, It looks like you don't want to

> answer my question about which roads the traffic

> displaced by the OHS scheme would end up using.

> Any reason why please?

[JohnL]

first mate Wrote:

-------------------------------------------------------

> In fairness, eD generally does answer questions

> and no doubt will this one.

>

> slarti b Wrote:

> --------------------------------------------------

> -----

> > exDulwicher, It looks like you don't want to

> > answer my question about which roads the

> traffic

> > displaced by the OHS scheme would end up using.

>

> > Any reason why please?

If traffic doesn't move then people will find another way - that's the plan.

In Wales they've just cancelled the M4 bypass amid moans and fury - but traffic schemes are being cancelled everywhere. Just maybe people know something about the future we don't - it's going to be driverless.

[Rockets]

JohnL Wrote:

-------------------------------------------------------

> first mate Wrote:

> --------------------------------------------------

> -----

> > In fairness, eD generally does answer questions

> > and no doubt will this one.

> >

> > slarti b Wrote:

> >

> --------------------------------------------------

>

> > -----

> > > exDulwicher, It looks like you don't want to

> > > answer my question about which roads the

> > traffic

> > > displaced by the OHS scheme would end up

> using.

> >

> > > Any reason why please?

>

> If traffic doesn't move then people will find

> another way - that's the plan.

>

> In Wales they've just cancelled the M4 bypass amid

> moans and fury - but traffic schemes are being

> cancelled everywhere. Just maybe people know

> something about the future we don't - it's going

> to be driverless.

You're absolutely right, people are finding another way and that is why the surrounding roads around the DV closure are so congested and polluted....which is exactly the point we are all trying to make...;-) So is the plan working then, close one road to force everyone onto other roads to slow journey times and increase pollution? Some plan that is....

And your claim that the future will be driverless isn't quite right as autonomous driving is some way off and will require significant infrastructural investment and 5G to make it happen....;-)

[Metallic]

Does anyone on here not feel at all guilty about traffic displacement? That report on 11% disappearing traffic is so out of date as to be meaningless in the particular geography of our bigger area. I feel guilty about Croxted Rd which will have it all coming down on them, along with Rosendale Rd. Or Lordship Lane.

[Serena2012]

Metallic Wrote:

-------------------------------------------------------

> Does anyone on here not feel at all guilty about

> traffic displacement? That report on 11%

> disappearing traffic is so out of date as to be

> meaningless in the particular geography of our

> bigger area. I feel guilty about Croxted Rd which

> will have it all coming down on them, along with

> Rosendale Rd. Or Lordship Lane.

As a resident of one of the roads directly impacted (EDG) all I can say is that the traffic has increased significantly as a result of these closures. I am very concerned about what Autumn will bring (both in terms of further closures; the weather causing those who might otherwise travel actively to jump into cars, and the impact of the schools returning).

Against this backdrop, the council?s seeming reluctance to commit to any form of detailed monitoring of the impact on the boundary roads seems utterly bewildering. I can only assume that this is because they wish to avoid the inconvenient truth, which is that all these schemes are doing is to shift the burden of heavy traffic and resultant pollution from one affluent part of the neighbourhood, where car ownership is very high, to its poorer streets. Poorer streets where car ownership is far lower, and where accordingly, many of the residents are not the source of the congestion, yet have to live with the life long health consequences. Poorer streets which house the majority of the area?s schools, and a significant proportion of the area?s social housing.

They are doing so against the backdrop of a body of overwhelming evidence demonstrating the significant adverse impact air pollution has on children; in the knowledge that idling traffic is far more polluting than free flowing traffic, as well as evidence indicating that even a small increase in air pollution (of 1 microgram per cubic metre of pm2.5) significantly increases the risk of severe morbidity and mortality in the context of COVID-19. They are also doing so in full knowledge that the last census data shows that many of the streets set to bear the burden of these changes have a much higher BAME population than those that will benefit, in circumstances where evidence suggests that people from BAME backgrounds are more vulnerable to Covid-19. This in my view is utterly unconscionable.

[roywj]

There is clearly significantly more traffic at a standstill during rush hours in Dulwich Village travelling towards the crossroads at Village Way/EDG/Red Post Hill. This will get worse when schools return and will increase pollution for Dulwich Infants, Dulwich Hamlet & JAPs schools.

There is also clearly significantly more traffic at a standstill during rush hours on East Dulwich Grove looking to turn right into Townley Road. This again will get worse when the schools return and will increase pollution for JAGs.

Both issues above can be clearly linked to the road closure on Calton Avenue. I understand that there was a traffic problem on Calton Avenue but closure of the road has created the problems above affecting pollution levels outside local schools.