West Dulwich LTN Action Group - needs your support

[raptortruckman69]

Well Aldred is wrong about most stuff but if she is right about something then why would we criticise that? Being right makes someone much more credible than being wrong so she is definitely credible when she says those tubes didn't work properly. Why do you find that INcredible hahaha!

Anyway who actually believes the manufacturers claim that they are 95% accurate? Of course they would say that. They are hardly going to say we heavily undercount cars. The councils want LTNs so they can collect fines and the councils are the customer of the company. The company is going to give the council what it wants. They are not being paid for the truth.

Come on think. If we are honest we can all see LTNs don't work so any data that says they might must be dodgy.

 

 

Edited October 3 by raptortruckman69

[exdulwicher]

34 minutes ago, Rockets said:

This one FM?

 

There are known issues with data quality. Usually, reports used Automatic Traffic Counters (ATCs) to monitor traffic, in most cases ‘tubes’ across the road. These are imperfect. Parked or very slow-moving motor traffic may affect results; although in most cases, count sites were placed away from junctions where queueing is likely, which should reduce this problem. Data problems due to parking may be more an issue on internal residential roads than on boundary roads. Adjusting for expected changes should help control for such bias as that data too is largely based on ATCs. We have not accessed raw data directly from counters, as this would not be feasible for so many count points, schemes, and boroughs (and data may be held by contractors). It is possible that authorities or contractors have made errors6 (in one report a clearly wrong count was given for one site, for instance). We believe that a small number of undetected errors should not bias the overall results; and sensitivity analyses assess if any borough’s exclusion substantially changes the results.

That's called sound methodology. It accepts and explains that not all data is good and - once again - there is a wider context. It's not specifically about tube counters, it's more to do with the overall data supplied by some (not all) councils not being up to the required standard for analysis so it gets discarded, ignored from the overall review. This is entirely normal in statistics, you invariably get some data that is corrupt, insufficient etc so, unless it can be properly validated and revised, it gets discarded. This should actually play into the hands of the anti-LTN folk cos there are fewer chances to prove LTNs are good.

However the overall review of all the schemes using all the data that is available, was still overwhelmingly positive.

Back to the tube counter stuff.

They get extensively tested and validated by the councils, authorities etc that buy them. No-one is going to buy into a scheme that gives duff data but these counters are used all over the world. It's very easy to validate this stuff - you can run test scenarios, cross-reference with other independent sources of data and apply corrective factors if required, none of this is in any way unusual or radical.

The tubes do more than just count vehicles. They measure speed (so it's easy to tell if it's free-flowing traffic or congestion), vehicle type and (depending on placement) they can also determine things like queue length and you can extrapolate from that delay times which is why it's actually quite handy to have them near junctions sometimes; it can measure how far back from the junction is routinely becoming congested. 

And as I said before, the info that the tube counters gives is cross-referenced with other data and compiled to give an overall picture. You're not after counting every vehicle on every road; you're after overall trends and patterns, increases and decreases over time and the reasons behind that - reasons which could include a new housing estate / school / supermarket etc causing an increase or a School Street / LTN causing a decrease.

As a quick example, the most common "road load" number is called AADT - Annual Average Daily Traffic. It's basically a count of X vehicles use this road in a week then it must be X x 52 in a year or X/7 per day. That's useful for calculating expected wear and tear on the road, roadworks frequencies etc but it doesn't give the exact pattern of use because it's not (eg) 1200 vehicles per day spread neatly as 50 vehicles per hour 24/7. It's a very uneven load of <10 vehicles per hour at night rising to maybe 300 per hour for 90 mins in morning peak and then dropping off sharply during the day then rising again in the afternoon. However the AADT figure is widely used as an overall number. It's a good example of how you need a number of data points to give you the overall picture of road use.

So in short, yes, the counters are fine.

[first mate]

51 minutes ago, Rockets said:

This one FM?

 

There are known issues with data quality. Usually, reports used Automatic Traffic Counters (ATCs) to monitor traffic, in most cases ‘tubes’ across the road. These are imperfect. Parked or very slow-moving motor traffic may affect results; although in most cases, count sites were placed away from junctions where queueing is likely, which should reduce this problem. Data problems due to parking may be more an issue on internal residential roads than on boundary roads. Adjusting for expected changes should help control for such bias as that data too is largely based on ATCs. We have not accessed raw data directly from counters, as this would not be feasible for so many count points, schemes, and boroughs (and data may be held by contractors). It is possible that authorities or contractors have made errors6 (in one report a clearly wrong count was given for one site, for instance). We believe that a small number of undetected errors should not bias the overall results; and sensitivity analyses assess if any borough’s exclusion substantially changes the results.

 

 

Yes, thanks.

There is a clear statement saying there are known issues with ATM data. Slow moving traffic is mentioned in this context.

Aldred later explains how she 'believes' these data flaws can be mitigated and should not affect the overall results ... They did not access or use the raw data. 

Aldred also touches on siting of counters. Was siting an issue with ATMs in the Dulwich area?

 

 

 

 

 

 

 

[Rockets]

Thanks Ex- - it's so good to have you back!

Whilst you say they are "fine" and good when used with other monitoring sources of data do you have any thoughts on my questions below:

 

• Was Metrocount right to say: the counters are “not designed to work” in stop-start traffic?
• Do pneumatic tubes work well in road conditions under 10km/h and in congested traffic?
• Do you have to reset them/use them differently to specifically count vehicles under 10km/h and, if so, does that impact overall accuracy or do you have to do two separate sets of monitoring?
• Why do you think the MetroCount default setting is only over 10km/h out of the box?
• Would moving tubes from Lordship Lane at the junction of Court Lane to Lordship Lane to the junction of Melford Road (which is often under heavy congestion) increase or decrease accuracy of the monitoring provided by the tubes?

It seems that tubes do have flaws and the sooner everyone moves to Vivacity monitors the better - at least we will have more definitive data that cannot be accused of being used to manipulate the outcome - this is why so many people have had problems with the way councils have conducted themselves over monitoring - they have appeared to try everything in their power to prove their LTNs have been a success and when they make such a hash of the monitoring element it creates suspicion.

I still laugh heartily when I think the lengths Southwark went to monitor the streets inside the Dulwich LTN and then had to be forced to monitor outside!

4 minutes ago, first mate said:

Was siting an issue with ATMs in the Dulwich area?

This really depends on whether they monitor well under 10km/h or not. Certainly when the monitoring started the tubes were positioned in different places to where they ended up for the majority of the monitoring programme. I think Ex- has said previously that moving them is often deliberate but I know for a fact that the one that was on Lordship Lane at the junction of Court Lane was moved to adjacent to Melford Road (so under slow moving congested traffic for much of the day) and the siting of many of them was close to junctions. The ones in Dulwich Village were very close to the traffic lights and junctions.

If they capture everything under 10km/h then clearly no problem but if they lose accuracy under 10km/h then you have to suggest the placement and movement of them was suspicious to say the least.

[Earl Aelfheah]

So there you go. Claim the manufacturer has said one thing. Then when they are quoted saying the opposite, switch track.

Irrelevant as it is to what you claimed the manufacturer has said, let’s look at the that paper. It concludes that LTNs have a positive impact in reducing traffic. Something that presumably you also accept now. Good news!

You have selectively quoted from the bit of the paper discussing limitations, and which describe ATCs as ‘imperfect’. Had any other count method been used, including manual counts, the limitations of those methods would also have been discussed, because that's how academic analysis works, and all methods have limitations. All are imperfect. The section discussing limitations concludes: ”a small number of undetected errors should not bias the overall results". It does not say they are inaccurate (not to any degree that would substantially change the results), simply that they are 'imperfect'. The manufacturer also acknowledges that their ATCs are imperfect, but says that they are still very accurate (accuracy exceeding 95%). 

And then there is the fact that you have quoted from someone who you have repeatedly disparaged, and described as lacking credibility, but have admitted that you are wiling to accept as an expert only in so far as they say something you (mistakenly) think says something that backs up a completely different point that you've made about the manufacturer having 'admitted' something that they clearly have not. 

But fundamentally it’s all irrelevant. Your claim was about what the manufacturer had said in relation to their product and on that it is very clear that you are wrong and incapable of just admitted your error like a grown up.

Edited October 3 by Earl Aelfheah

[Rockets]

4 minutes ago, Earl Aelfheah said:

Then when they are quoted saying the opposite, switch track

Err, hardly. The only switching of track is the way you tried to put words into my mouth that I did not actually say.

 

6 minutes ago, Earl Aelfheah said:

ou have quoted a section from a paper that finds that the conclusions reached on LTNs is reiable.

I think everyone can read the section of that paper for themselves and come to their own conclusion - it's pretty damn clear what she is saying - confirmation bias or not. Only those who are beyond blinkered would/could read it any other way or try to spin any other conclusion.

 

1 hour ago, exdulwicher said:

Parked or very slow-moving motor traffic may affect results; although in most cases, count sites were placed away from junctions where queueing is likely, which should reduce this problem.

Unfortunately for you this (from Aldred not Ex- I hasten to add)  massively undermines your position - I am sure you have convinced itself it doesn't but it does and it was exactly what I saying from the outset - and that was the original message I posted before you tried to change it to what you hoped I had said.

11 minutes ago, Earl Aelfheah said:

She is not suggesting that they are inaccurate to any significant degree, merely imperfect.

"merely imperfect" - ha ha....the mere imperfectness of the system may affect results in very slow-moving traffic.

[Earl Aelfheah]

The paper concludes that LTNs have a positive impact in reducing traffic. So I assume that you accept that Rockets?

9 minutes ago, Rockets said:

"merely imperfect" - ha ha....the mere imperfectness of the system may affect results in very slow-moving traffic.

Yes, the Rachel Aldred paper does not say they are inaccurate (”a small number of undetected errors should not bias the overall results"), simply that they are 'imperfect'. The manufacturer also acknowledges that their ATCs are imperfect, but states that they are still 'very accurate' (with accuracy exceeding 95%).

All counting methods, including manual counting are imperfect. 

This is also completely irrelevant to your false claim about that the manufacturer has said they are inaccurate when they have in fact said the exact opposite.

Edited October 3 by Earl Aelfheah

[Rockets]

That's not what we are talking about and is a desperate attempt by you to change the subject (I wonder why) - we are talking about the part of the ALdred report that deals with the "mere imperfections" of the tubes for monitoring very slow-moving traffic. If you want to start another thread feel free.

9 minutes ago, Earl Aelfheah said:

Yes, the Rachel Aldred paper does not say they are inaccurate (”a small number of undetected errors should not bias the overall results"), simply that they are 'imperfect'. The manufacturer also acknowledges that their ATCs are imperfect, but states that they are still 'very accurate' (with accuracy exceeding 95%).

But she states this.....Parked or very slow-moving motor traffic may affect results; although in most cases, count sites were placed away from junctions where queueing is likely, which should reduce this problem.

Honestly.....how difficult is this to get your head round....

Edited October 3 by Rockets

[Earl Aelfheah]

You said something that was untrue and you can't bring yourself to simply admit it. You've now switched track from making false claims about what the manufacturer has said about their own product, to quoting someone else (who you've previously mocked as lacking credibility.. quite unfairly I might add). It is you who are desperately trying to change the subject. 

Edited October 3 by Earl Aelfheah

[Rockets]

But I didn't.

 

Earl, give up...honestly it's not worth it - you're really not helping your cause - you're looking incredibly irrational.

Just let everyone make their own minds up. I have said what I said (not what you said I said I hasten to add) and presented (what I believe to be) more than compelling evidence to back it up from numerous sources. You don't agree and the evidence will not sway you - that's fine - we will just have to agree to disagree.

[Earl Aelfheah]

You didn't claim that ATCs were imperfect, or that Rachel Aldred had said that ATCs were imperfect.

What you did claim was that the manufacturer had 'admitted' that their ATCs were inaccurate at counting vehicles travelling under 10mph. 

“MetroCount says that its tube-based counters are still very accurate for traffic volumes, even under very slow and congested traffic conditions... It says that in most circumstances this would exceed 95 per cent accuracy”

You often use this tactic - say something that is untrue or misleading and then try to change track and say 'that's not what we're discussing', meaning you're trying not to discuss it anymore. It's extremely transparent.

Anyway, as you're clearly never going to correct the record, let me ask you this: Now that you have found that you do in fact value Rachel Aldred's expertise; The paper you’ve quoted from concludes that LTNs have a positive impact in reducing traffic. Can we assume that you accept that conclusion?

Edited October 3 by Earl Aelfheah

[first mate]

Earl, again you have moved the debate into the general, which is clearly where you feel most comfortable. These threads are ED specific. Can you say, categorically, that Aldred's research proves that data for ED LTNs was not in any way flawed? 

[Rockets]

2 hours ago, Earl Aelfheah said:

You didn't claim that ATCs were imperfect, or that Rachel Aldred had said that ATCs were imperfect.

But I used that to illustrate how my position was correct after you went at me saying I was wrong. It’s called providing evidence to back up your claim.

Your evidence? A PR line from the company who makes the product.

2 hours ago, Earl Aelfheah said:

What you did claim was that the manufacturer had 'admitted' that their ATCs were inaccurate at counting vehicles travelling under 10mph. 

Wrong again. I said under 10kmp/h. Another deliberate mistake? You should really pay more attention to detail.

2 hours ago, Earl Aelfheah said:

Anyway, as you're clearly never going to correct the record, let me ask you this: Now that you have found that you do in fact value Rachel Aldred's expertise; The paper you’ve quoted from concludes that LTNs have a positive impact in reducing traffic. Can we assume that you accept that conclusion?

I have nothing to correct. I think I have more than made, and validated, my point. I discussed my thoughts on Aldred’s paper when it was released, feel free to take a look or start a new thread and I would be happy to discuss but you can’t use that to try to deflect away from this thread - that’s a tactic played by some of your erstwhile friends when a subject gets too hot for them!

 

2 hours ago, Earl Aelfheah said:

You often use this tactic - say something that is untrue or misleading and then try to change track and say 'that's not what we're discussing', meaning you're trying not to discuss it anymore. It's extremely transparent.

Oh come on Earl, are you playing deliberately stupid? I said that’s not what we’re discussing when you tried to deflect the conversation onto the strengths cited in Aldred’s report.

[Dogkennelhillbilly]

1 hour ago, first mate said:

These threads are ED specific. 

Actually, this thread is supposed to be about the proposed changes to the West Dulwich LTN, but some monomaniac is still wanging on about Southwark Council's supposed crimes in East Dulwich 4 years ago...

[first mate]

If the irrelevant old news you suggest, I doubt you and a few others would consistently pay such close attention, as well as put such effort into closing the subject down.

Earl and chums want to talk about LTNs in general, they do not want to address the issue of flawed data for local Dulwich LTNs. 

Edited October 4 by first mate

[Spartacus]

BBC News - West Dulwich LTN: Residents make legal threat to Lambeth Council - BBC News

https://www.bbc.co.uk/news/articles/ce8vzze2y7xo

Hit the BBC news website today 

Love the quote from Lambeth Council's deputy leader councillor Rezina Chowdhury who says "we know these things work" as she forces an LTN trial on residents who clearly don't want it.  From experiences of Southwatks "trials",  they get modified and made permanent despite continued objections from residents. 

[Earl Aelfheah]

10 hours ago, Rockets said:

Wrong again. I said under 10kmp/h. Another deliberate mistake? You should really pay more attention to detail.

Which is also untrue.

“MetroCount says that its tube-based counters are still very accurate for traffic volumes, even under very slow and congested traffic conditions... It says that in most circumstances this would exceed 95 per cent accuracy”

It's really very sad that when you have claimed the manufacturer has said one thing and they are clearly on the record saying something else, that you can't just be man enough to admit a mistake.

Edited October 4 by Earl Aelfheah

[Rockets]

You keep misquoting me - is this deliberate or are you just not very good at detail?

I remind you Earl, Purdue Pharma claimed that Oxycontin wasn't addictive...

You're clearly a MetroCount fanboi as, despite overwhelming counter evidence from a host of sources, you keeping drinking their Kool-Aid! Do you work in their PR department per chance? 

P.S. Also some sound advice: treat with some suspicion when companies say things like "in most circumstances".....

[Earl Aelfheah]

Don't be silly. You're the one that started citing the manufacturer, claiming that they'd 'admitted' their products were inaccurate at counting slow moving vehicles. I'm just pointing out that they haven't said the things you claimed. 

It's funny how, as with Rachel Aldred, you’re happy to cite someone as a reliable and credible source only in so far as you think they may confirm something you already believe, or would like to believe, whilst rubbishing them the rest of the time. 

But whether a particular source (that you original quoted) is reliable or not, is of course, irrelevant. It really is just a case of you stating someone had said one thing, when they in fact they have said something else, and choosing to deflect and obfuscate rather than simply admit a mistake.

Edited October 4 by Earl Aelfheah

[raptortruckman69]

I agree with rockets. The counter company is big pharma level of deceptive. All the "evidence" that shows LTNs are a success is manipulated.

We KNOW the LTNs are a failure. All the mounds of "evidence" to the contrary must be fake.

 

[Rockets]

2 hours ago, Earl Aelfheah said:

But whether a particular source (that you original quoted) is reliable or not, is of course, irrelevant. It really is just a case of you stating someone had said one thing, when they in fact they have said something else, and choosing to deflect and obfuscate rather than simply admit a mistake.

A bit rich coming from someone who has, repeatedly, lied about what I said and tried to change what I have said to suit their particular agenda. But, you know, hypocrisy is an overpowering trait demonstrated by many who claim to be on the pro-side of the debate!

It is very clear the point I was trying to make - you are the pedant who has then spent days arguing the yeah, but, did you mean classifying or counting and trying to take the conversation down a rat hole.

It's very clear that MetroCount devices are not great at monitoring under 10kmp/h and that is validated by a lot of different sources including the company themselves, Rachel Aldred and other documents posted by others on here.

Of course we have to acknowledge that the company themselves (and you) claim this is not the case but, on the weight of presented evidence, only a fool would take their word for it!

2 hours ago, Earl Aelfheah said:

and choosing to deflect and obfuscate rather than simply admit a mistake.

Again a bit rich and hypocritical coming from you given your track record of, repeated, mistakes (about what I have said) on this thread alone. 

[Earl Aelfheah]

22 minutes ago, Rockets said:

Of course we have to acknowledge that the company themselves (and you) claim this is not the case but, on the weight of presented evidence, only a fool would take their word for it!

You were the one who suggested we should take their word for it, when you (falsely) claimed that they had stated the equipment didn't work at counting slow moving traffic. 

But at last you finally accept that the company have indeed said otherwise. It only took several pages of deflection for you to finally sneak that mealy mouthed climb down in.

Edited October 4 by Earl Aelfheah

[Rockets]

On 30/09/2024 at 18:04, Rockets said:

On 30/09/2024 at 16:00, Earl Aelfheah said:

This is nonsense. As previously discussed 

You might think it is nonsense but others do not and the weight of evidence suggests our position is a more reflection of reality than yours.

 

Let's look....

• The manufacturer admitted they are not accurate under slow moving traffic (10kmph) 
• Southwark council stated they were phasing them out and replacing them with more accurate counters
• Even our dear friend Ex-Dulwicher (who works in this sort of stuff) admitted that they are not accurate when used in heavy traffic conditions.

So combine all of the above with the fact that Southwark actively moved monitoring strips closer to choke points (to use their weaknesses to their advantage) then my statement is anything but nonsense.

I don't know where Lambeth have put the monitoring strips in West Dulwich but if they are in areas of slow moving traffic then the pneumatic strips will not be providing an accurate reflection of traffic levels - that is not nonsense, that is a fact.

Ha ha acknowledging what a company has said hardly constitutes a "mealy mouthed climb down" but you referring to it as such is probably a reflection on what your modus operandi is at the moment. 

Let's just remind ourselves where this all started and the statements I actually made (before you started to apply your own unique interpretation/lying to try and land a point).

 

• The manufacturer admitted they are not accurate under slow moving traffic (10kmph) 
• Southwark council stated they were phasing them out and replacing them with more accurate counters
• Even our dear friend Ex-Dulwicher (who works in this sort of stuff) admitted that they are not accurate when used in heavy traffic conditions.

Nothing in those three original statements is inaccurate.

Edited October 4 by Rockets

[raptortruckman69]

Ok I'm confused now. Is the company lying about accuracy or saying they can't accurately count cars. I thought it was the first one because it looks like they say they are accurate

[exdulwicher]

2 minutes ago, Rockets said:

• Even our dear friend Ex-Dulwicher (who works in this sort of stuff) admitted that they are not accurate when used in heavy traffic conditions.

Nothing in those three original statements is inaccurate.

I feel I'm being misquoted or at least selectively quoted.

It is very easy to check for and compensate for inaccuracies by cross-referencing with other sources of data. No-one is using these in isolation, they are there to support other sources. If there are wild disagreements between what the sensor is saying and what congestion monitoring, manual traffic counts, video feeds, bus journey times etc are all saying then you can investigate further, maybe disregard the bad stuff, reposition the sensor, apply a correction factor etc. 

You would also have a look for local events that could have caused a change to the normal traffic pattern. 

And as I also mentioned, you do not need to count every vehicle on every road and the idea that even a single vehicle missed is some kind of "OMG, teh D4tA i5 BAD!!!" gotcha is simply not true. The fact is that even "bad data" can be very useful in highlighting issues and errors.