West Dulwich LTN Action Group - needs your support

[Rockets]

Earl, let's just agree to disagree. You take the word of MetroCount, I will take the word of the likes of Rachel Aldred and people who actually know what they are talking about.

You've been wrong on a lot of other things in the past and we will just add this to the list! 😉

What do they say about arguing with.....

4 hours ago, Rockets said:

The company says the counters are “not designed to work” in stop-start traffic and are recommended to be used in “free-flowing conditions”.

Sometimes the answer is staring right at you from the page! Denial is not a river in Africa! 😉

By the way, would you care to enlighten us as to why you think the MetroCount devices aren't accurate (your claim) for vehicle classification (which you are suggesting they are admitting to) under 10km/h but are for counting?

Edited October 2 by Rockets

[Dogkennelhillbilly]

5 hours ago, first mate said:

Rockets remembered Ex-Dulwicher commenting that they were not good in congested/ slow moving traffic. I got the impression Ex knew a lot about this area and had worked in it.

One pseudonymous poster rehashing another pseudonymous poster's memory about a third pseudonymous poster's opinion is not data or evidence either! 🤣🤣🤣

[raptortruckman69]

Obviously Metro count are being dishonest or deluded about the accuracy of their machines for slow vehicles, that's why the numbers are lower. When the numbers go up we will start believing Metro counts figures.

[Rockets]

To be fair DKHB, Ex-Dulwicher seemed a darn sight more qualified to pass comment on such things than Earl, Ex at least claimed to work n the industry and they said (my how we miss their learned and informed opinion):

Southwark (as with many boroughs in London and cities outside London as well) are moving a lot of their monitoring to Vivacity sensors. They're the camera type things with double lenses you can see on a lot of lampposts around the area and they're vastly more accurate, they can measure pedestrian, bike, car, truck, bus etc very accurately and also measure things like turning flow. They're largely immune to congestion issues and slow moving traffic, or at least can process this as part of the whole package (speed low, flow low, count low = congestion).

 

 

BTW well done to the West Dulwich Action Group for getting a segment on the BBC London news tonight.

[Dogkennelhillbilly]

19 hours ago, Dogkennelhillbilly said:

The "data doesn't care about your feelings" crowd do really seem to struggle with the concept of citing data and providing sources. 🤔 

As an follow-on observation, there seems to be a enthusiasm in some quarters for claiming to have seen things but not citing or sharing the actual data. For example:

https://x.com/DulwichCleanAir/status/1838479733199376440

[exdulwicher]

10 hours ago, Rockets said:

To be fair DKHB, Ex-Dulwicher seemed a darn sight more qualified to pass comment on such things than Earl, Ex at least claimed to work n the industry and they said (my how we miss their learned and informed opinion):

Southwark (as with many boroughs in London and cities outside London as well) are moving a lot of their monitoring to Vivacity sensors. They're the camera type things with double lenses you can see on a lot of lampposts around the area and they're vastly more accurate, they can measure pedestrian, bike, car, truck, bus etc very accurately and also measure things like turning flow. They're largely immune to congestion issues and slow moving traffic, or at least can process this as part of the whole package (speed low, flow low, count low = congestion).

Oh bless. 

II think I've found the post you're referring to in the Streetspace thread, 15th May 2023? 

 

Feel free to tell me if it's another one of mine that you've found though.

Right - accuracy. Tube counters work to supplement other sources of data (including, but not limited to) mobile phone/satnav data, roadworks databases, information from other sensors (such as Vivacity, independent traffic counts, TfL cameras etc) and their advantage is that a number of them can be deployed pretty quickly and at any location. They're left in place for a period of time, come of them upload data to the cloud of their own accord, some of the older ones need collecting and downloading. 

Location: You can NEVER have a free-flowing road by the way. Any road, from the smallest cul-de-sac off LL to the M1 can be subject to "congestion", it might be 5 minutes cos Amazon and DPD can't agree on which of them needs to back up, it might be 30 minutes while the refuse collection truck potters along the street or it might be a day cos some idiot has rammed their SUV into the bollards along EDG again.

The data: you look at the traffic counts and cross-reference.
Example: Oh look, there's a 30-min period on Tuesday morning when only 6 cars went across it. What does it look like either side of that timeframe? What does it look like on other days? What was the counter up the road saying about traffic going the other way? What would we *expect* at this time on a Tuesday morning? But rather than look at that one 30-min timeframe, you're doing it over the whole of the period it was left in place, looking for TRENDS. It doesn't matter if one day there's 1000 vehicles and every other day there's only 850 - trends like that are pretty regular (Friday afternoons!), you can often pick out individual events (such as a football match or a school open day, which is another source of cross-reference) and, if you do that often enough over a period of months, you gain a very good understanding of traffic trends that smooths out the short notice congestion stuff like a particularly busy day or a single accident or a 2 week period of roadworks. 

Crucially, they are as accurate as they need to be for supplementing other sources of data and for being rapidly deployed on pretty much any road in the borough, unlike more permanent sensors such as the Vivacity ones which need wiring into the lamp column, calibrating and verifying. 

Quick analogy is that a pilot doesn't just rely on one instrument to show their speed; they'll have GPS, air speed indicator (uncalibrated), True Airspeed (which is the uncalibrated figure corrected for altitude and temperature), Ground speed (which is True adjusted for wind speed and direction), mach number indicator... 

It's the same here. What's also the same is that no matter how much data there is and how much the council publish, the anti-folk will always claim it's not enough, it's not in the right place, or the right time, it's not representative, it's not accurate, it's fake... Except if the data shows an increase in traffic at which point it'll be 100% valid and all traffic schemes should instantly be removed cos it's a dead-cert that they've failed.

 

[Rockets]

Ex- welcome back - oh how I have missed debating/arguing with someone who comes from a position of knowledge!!! 😉

 

So, to shut either Earl or I up once and for all and to give one of us eternal bragging rights and everyone else a rest from our bickering 😉 can you answer this:

 

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?

 

56 minutes ago, exdulwicher said:

What's also the same is that no matter how much data there is and how much the council publish, the anti-folk will always claim it's not enough, it's not in the right place, or the right time, it's not representative, it's not accurate, it's fake..

Yes and by the same measure the pro folks will point to data put out by those rolling out these measures and say..."look, proof it is working the council have said everything is awesome and so it must be" without every bothering to check the detail....Unfortunately this is the world we live in, everything is very binary...you're either in or out....no-one can take a little bit of this and a little bit of that and occupy the (pragmatic) centre ground - if the headline suits your agenda you'll amplify it - everyone does it!

[raptortruckman69]

Also were they right to say that traffic counts are 95% accurate even with congestion?

 

But we all know the answer because the sensors showed a decrease, and that's obviously rubbish.

 

 

[malumbu]

3 hours ago, Rockets said:

Ex- welcome back - oh how I have missed debating/arguing with someone who comes from a position of knowledge!!! 😉

 

So, to shut either Earl or I up once and for all and to give one of us eternal bragging rights and everyone else a rest from our bickering 😉 can you answer this:

 

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?

 

Yes and by the same measure the pro folks will point to data put out by those rolling out these measures and say..."look, proof it is working the council have said everything is awesome and so it must be" without every bothering to check the detail....Unfortunately this is the world we live in, everything is very binary...you're either in or out....no-one can take a little bit of this and a little bit of that and occupy the (pragmatic) centre ground - if the headline suits your agenda you'll amplify it - everyone does it!

Wow this is precious, If I recall Ex was in broad support of measures to discourage motoring, And Rockets disagreed with much of what Ex posted.

I look forward to the time when Rockets acknowledges me, as a transport professional/expert who has delivered sustainable programmes.

I'll try and find some earlier discussions.

[Earl Aelfheah]

16 hours ago, Rockets said:

I will take the word of the likes of Rachel Aldred and people who actually know what they are talking about

You have repeatedly said that Rachel Aldred is biased, and rubbished her research findings. For what it's worth I think she is a highly credible expert, but it's ridiculous that you're now holding her up as someone whose opinion you value, when you've posted multiple time about how she's part of a pro-LTN conspiracy and totally unreliable. 

Edited October 3 by Earl Aelfheah

[Rockets]

14 minutes ago, Earl Aelfheah said:

You have repeatedly said that Rachel Aldred is biased, and rubbished her research findings. For what it's worth I think she is a highly credible expert, but it's ridiculous that you're not holding her up as someone whose opinion your value, when you've posted multiple time about how she's part of a pro-LTN conspiracy and totally unreliable. 

I do value her opinion on the fact that Parked or very slow-moving motor traffic may affect results (in relation to monitoring tubes)

18 minutes ago, malumbu said:

I look forward to the time when Rockets acknowledges me, as a transport professional/expert who has delivered sustainable programmes.

Sorry to break it to you Malumbu but this is not about you....

[Earl Aelfheah]

4 hours ago, Rockets said:

So, to shut either Earl or I up once and for all and to give one of us eternal bragging rights and everyone else a rest from our bickering 😉 can you answer this:

Was Metrocount right to say: the counters are “not designed to work” in stop-start traffic?D

Ok, one more time, with the relevant context. The Times article that you are quoting says:

"The company says the counters are “not designed to work” in stop-start traffic and are recommended to be used in “free-flowing conditions”. [note these quotes have already been heavily edited down to two discontinuous three word snippets with commentary placed in between them by the Time's journalist; a journalist that has written well over 30 anti-LTN, anti-ulez articles, plus several about the 'war on motorists']

It explained: “Vehicles travelling very slowly might not be classified correctly, either the axle hits are too far apart so it splits them and places them into an unknown vehicle class, which doesn’t get included by default, or it attaches those axle hits to a vehicle in front or behind.”
MetroCount says that its tube-based counters are still very accurate for traffic volumes, even under very slow and congested traffic conditions because the axles passing are continuously recording. It says that in most circumstances this would exceed 95 per cent accuracy"

What this means is that in stop-start traffic you may have issues with vehicle classification, but they are still very accurate at counting traffic volumes (at least according to the manufacturer), which is how they're used to monitor the impact of LTNs.

You keep highlighting a comment (already with context removed in the article) taking out the explanation which follows regarding classification versus volume / counts. You also completely ignor the most relevant part which directly addresses their view on the accuracy of vehicle counts:

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

Whether one should rely on what the manufacture says is a another question. Your claim was that they had 'admitted' that their product couldn't count vehicles travelling under 10mph, which again, for the avoidance of doubt, is clearly, demonstrably untrue.

59 minutes ago, Rockets said:

I do value her opinion on the fact that Parked or very slow-moving motor traffic may affect results (in relation to monitoring tubes)

This is literally the definition of confirmation bias. You will rubbish her research, impugn her credibility, but only in so far as what she says doesn't conform to something you already believe, or want to believe. It shows that you are not a serious person.

Edited October 3 by Earl Aelfheah

[first mate]

34 minutes ago, Rockets said:

53 minutes ago, malumbu said:

I look forward to the time when Rockets acknowledges me, as a transport professional/expert who has delivered sustainable programmes.

 

🤣🤣🤣
 

Not my area, and I defer to others who know more but:

Accuracy of pneumatic road tube counters

Author(s)

McGowen, P.; Sanderson, M.

Year

2011

• Abstract (EN)

 

Pneumatic road tube counters are a tool that is commonly used to conduct traffic counts on streets and roads. Many professionals have high confidence in the accuracy of road tube counts, and vendors of pneumatic road tubes often claim accuracy rates in the neighborhood of 99 percent. Several studies have been conducted in Montana intended to test the accuracy of road tube count data. These studies have compared road tube data to hand counts and other traffic-counting technologies, and compared results among multiple road tubes set up in series at a single location. The studies found that though the average error in a daily traffic count might be near zero, the absolute error of a typical 15-minute count averaged closer to ten percent. These results suggest that the level of inaccuracy is being masked by the positive and negative counting errors canceling each other out. Errors in speed and classification were much greater. These results raise questions about the reliability of pneumatic road tube counters in accurately measuring traffic volumes. This report compiles the results of these studies and provides a framework for measuring and reporting error.

Edited October 3 by first mate

[Rockets]

52 minutes ago, Earl Aelfheah said:

This is literally the definition of confirmation bias.

No, those are words in a report she put her name to.

A report on LTNs and monitoring of LTNs.

Which definitely does not make it confirmation bias because there is no bias or interpretation applied to her words by me. It's  confirmation denial on your part....what do you think Rachel Aldred meant by the below then....it's pretty definitive isn't it?

It's on page 7 in this report under Strengths and Limitations:

https://westminsterresearch.westminster.ac.uk/download/74b26baccb2dbc0d26f1ca1773b3cdcd08402ef0e79fae1908f79d77c2cb7653/6168872/1-s2.0-S2213624X23001785-main.pdf

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.

[Earl Aelfheah]

9 minutes ago, Rockets said:

No, those are words in a report she put her name to.

A report on LTNs and monitoring of LTNs.

Which definitely does not make it confirmation bias because there is no bias or interpretation applied to her words by me. It's  confirmation denial on your part....what do you think Rachel Aldred meant by the below then....it's pretty definitive isn't it?

That's not what confirmation bias means https://en.wikipedia.org/wiki/Confirmation_bias

Edited October 3 by Earl Aelfheah

[malumbu]

Just delve into numerous threads on this site and you see repetition repetition repetition here's one:

Swipes at Ex, swipes at Earl and no doubt swipes at me and others who rightly believe action needs to be taken.  So not all about me eh?!

[Earl Aelfheah]

28 minutes ago, Rockets said:

It's on page 7 in this report under Strengths and Limitations:

https://westminsterresearch.westminster.ac.uk/download/74b26baccb2dbc0d26f1ca1773b3cdcd08402ef0e79fae1908f79d77c2cb7653/6168872/1-s2.0-S2213624X23001785-main.pdf

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.

You're deflecting as usual. You didn't claim that ATC's were imperfect. You claimed that the manufacturer had 'admitted' that they couldn't count vehicles travelling under 10 mph.

Also, re. the quote above, this is under the 'strengths and Limitations' section. You are of course ignoring the strengths, and ignoring the wider conclusions of the review (which is supportive of LTNs); As usual focussing on a couple of lines stripped of their wider context. You have also admitted that you only care about comments Rachel Aldred makes where you believe they might align to a view you already hold. Look up what confirmation bias is.

Edited October 3 by Earl Aelfheah

[Rockets]

34 minutes ago, Earl Aelfheah said:

You are of course ignoring the strengths

We're not arguing about the strengths.

34 minutes ago, Earl Aelfheah said:

and as usual focussing on a couple of lines stripped of their wider context.

Stripped of what context....do please enlighten me....they look pretty definitive to me.

In what context do you think they can be interpreted in any other way?

35 minutes ago, malumbu said:

So not all about me eh?!

No. You seem to be upset that I am recognising Ex-'s credentials to talk with knowledge about this subject but not giving you the same credit. Ex- talks from a far more rational and educated position on these matters. In my defence all I remember is you talking about is teaching kids to cycle, not much else to suggest you are a transport expert delivering sustainable programmes. Sorry if I missed something, perhaps start a new thread so you can enlighten everyone and we can all pay homage to your expertise....

34 minutes ago, Earl Aelfheah said:

Look up what confirmation bias is.

You're just upset that Aldred validates my position not yours and you're struggling to find an out. Or are you suggesting she means classify rather than monitor traffic....?

Edited October 3 by Rockets

[Earl Aelfheah]

7 minutes ago, Rockets said:

We're not arguing about the strengths.

Stripped of what context....do please enlighten me....they look pretty definitive to me.

In what context do you think they can be interpreted in any other way?

No. You seem to be upset that I am recognising Ex-'s credentials to talk with knowledge about this subject but not giving you the same credit. Ex- talks from a far more rational and educated position on these matters. In my defence all I remember is you talking about is teaching kids to cycle, not much else to suggest you are a transport expert delivering sustainable programmes. Sorry if I missed something, perhaps start a new thread so you can enlighten everyone and we can all pay homage to your expertise....

You're just upset that Aldred validates my position not yours and you're struggling to find an out. Or are you suggesting she means classify rather than monitor traffic....?

The context of the report which discusses the strengths and limitations and concludes that on balance, there is good evidence that LTNs are effective in reducing traffic.

Aldred does not validate your position in the slightest. Your position is that the manufacturers of ATCs have have 'admitted' that they can't count vehicles travelling under 10 mph. 

[first mate]

59 minutes ago, malumbu said:

Just delve into numerous threads on this site and you see repetition repetition repetition here's one:

Swipes at Ex, swipes at Earl and no doubt swipes at me and others who rightly believe action needs to be taken.  So not all about me eh?!

Malumbu, over the years you have taken many pretty low swipes and used all kinds of deflection methods, to the extent you were warned about it I don't think anyone needs lessons in posting from you. 

You do seem incredibly miffed that your 'expertise' has not been recognised. 

[Rockets]

24 minutes ago, Earl Aelfheah said:

The context of the report which discusses the strengths and limitations and concludes that on balance, there is good evidence that LTNs are effective in reducing traffic.

But, again, we are not discussing the strengths - we are discussing the limitations of monitoring tubes. And Aldred clearly validates my position and undermines yours.

 

25 minutes ago, Earl Aelfheah said:

Aldred does not validate your position in the slightest. Your position is that the manufacturers of ATCs have have 'admitted' that they can't count vehicles travelling under 10 mph. 

Earl now you're making things up and trying to put words into my mouth - what started this all was me saying:

• The manufacturer admitted they are not accurate under slow moving traffic (10kmph) 

Please try to be accurate.

[Dogkennelhillbilly]

5 minutes ago, first mate said:

You do seem incredibly miffed that your 'expertise' has not been recognised. 

Unless someone is willing to state their name and qualifications (malumbu, exdulwicher, uncle Tom Cobbly), any pseudonymous poster's supposed expertise is irrelevant because they could be making it all up. God knows we've seem enough barrack room traffic engineers, statisticians and physicists talk absolute nonsense on here.

The only thing worth discussing is factual data cited to real sources. Not "my online mate Terry reckons that Dulwich Park will be flooded next year" or "I've seen data that shows 80% of taxi drivers are left handed".

[first mate]

I have just read page 7 of the Aldred report, provided in a link by Rockets. The meaning is pretty clear. It clearly states that there can be issue with data collected by ATCs where there is slow-moving traffic or parked cars, especially near junctions, but adds this is often mitigated by placing the monitor away from junctions.

It would help if that one para could be cut and pasted, so all can see. I have tried but could not do it. No doubt Earl will argue that it does not mean what we think it means and is an example of our confirmation bias (a fave phrase of theirs).

Earlier I posted a study on Pneumatic counters from Montana (not London, I know) it too concludes that data accuracy is not as great as manufacturers claim.

 

 

 

Edited October 3 by first mate

[malumbu]

2 hours ago, Rockets said:

Can't get rid of this box, that's how qualified I am on IT.  I'll post later about my experience.

[Rockets]

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.