Traffic 'calming' and pollution

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Gfamily
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Re: Traffic 'calming' and pollution

Post by Gfamily » Thu Jun 17, 2021 11:46 am

FlammableFlower wrote:
Thu Jun 17, 2021 10:57 am
There's still the issue of brake and tyre particulate pollution with EVs. It'd be interesting if you had an area that only allowed EVs to compare the levels of pollution to ICE only areas.
Don't EVs often use regenerative braking?, so should be less particulates from brakes at least.
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Re: Traffic 'calming' and pollution

Post by lpm » Thu Jun 17, 2021 12:23 pm

Tessa K wrote:
Thu Jun 17, 2021 11:11 am
The traffic in London just gets slower, the pollution worse and people keep on driving.
Blatant fake facts.

Traffic is no slower than 1900. Pollution is down dramatically whether viewed over a decade or a century. Walking, bus passengers, underground use and cycling numbers are significantly higher over the past decade, car numbers are down.
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Bird on a Fire
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Re: Traffic 'calming' and pollution

Post by Bird on a Fire » Thu Jun 17, 2021 12:46 pm

lpm wrote:
Thu Jun 17, 2021 12:23 pm
Tessa K wrote:
Thu Jun 17, 2021 11:11 am
The traffic in London just gets slower, the pollution worse and people keep on driving.
Blatant fake facts.

Traffic is no slower than 1900. Pollution is down dramatically whether viewed over a decade or a century. Walking, bus passengers, underground use and cycling numbers are significantly higher over the past decade, car numbers are down.
No evidence that car numbers are down: https://roadtraffic.dft.gov.uk/regions/6
Screenshot_2021-06-17_13-35-52.png
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Plus a shift from A roads to minor roads does suggest that traffic is getting slower(?):
Screenshot_2021-06-17_13-36-49.png
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(The data is supposedly for London only - not sure why the subtitle says Great Britain)

Air pollution is down though - only 14 schools with illegally bad air pollution according to https://www.theguardian.com/environment ... port-finds It seems that the emissions charges have changed the types of vehicles used, rather than the numbers.
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lpm
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Re: Traffic 'calming' and pollution

Post by lpm » Thu Jun 17, 2021 1:06 pm

A 7 second google gives me this.

Image
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Gfamily
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Re: Traffic 'calming' and pollution

Post by Gfamily » Thu Jun 17, 2021 1:14 pm

https://www.london.gov.uk/questions/2019/19767
Weekday (07:00 to 19:00) speeds from 2008 to 2018 have changed from:

8.7 mph to 7.1 mph in central London
12.5 mph to 11.6 mph in inner London
20.3 mph to 19.3 mph in outer London
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Re: Traffic 'calming' and pollution

Post by monkey » Thu Jun 17, 2021 1:16 pm

And from Bird's link you can look at Candem and Islington by themselves, as they were the places mentioned in the OP. Both are down over the time period, Candem more so than Islington. No breakdown of road type though.

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Re: Traffic 'calming' and pollution

Post by Bird on a Fire » Thu Jun 17, 2021 1:22 pm

lpm wrote:
Thu Jun 17, 2021 1:06 pm
A 7 second google gives me this.

Image
Interesting

My googling took me to the Dept for Transport's London traffic page, yours took you to a blogpost from 2013, and they disagree.

Looking at the longer timeseries from the DfT site, there was a small decline between 2000 (20.1 billion miles) to 2013 (19.4 billion miles), though it's dwarfed by the increase in the runup to the pandemic. It's a bit clearer stripping out the other vehicle types:
Screenshot_2021-06-17_14-20-22.png
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As climate scientists before us have discovered, you've got to be careful with the limits of timeseries :)

ETA though as monkey points out, the decline in central London may well have continued, which is good news.
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Re: Traffic 'calming' and pollution

Post by lpm » Thu Jun 17, 2021 1:27 pm

Gfamily wrote:
Thu Jun 17, 2021 1:14 pm
https://www.london.gov.uk/questions/2019/19767
Weekday (07:00 to 19:00) speeds from 2008 to 2018 have changed from:

8.7 mph to 7.1 mph in central London
12.5 mph to 11.6 mph in inner London
20.3 mph to 19.3 mph in outer London
This shows car is still faster than bike for the time being, but at least the trend is in the right direction over the last decade. Cyclists average 12 mph to 16 mph - but the traffic lights and cycle jams in central London will bring this right down. Maybe rockdoctor can compete with a car but the average person won't.
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Re: Traffic 'calming' and pollution

Post by tom p » Thu Jun 17, 2021 1:46 pm

Tessa K wrote:
Thu Jun 17, 2021 11:11 am
tom p wrote:
Wed Jun 16, 2021 9:14 pm
Tessa K wrote:
Tue May 25, 2021 11:04 am
Road narrowing and closing sideroads for so-called 'traffic calming' and 'cleaner air' is a disaster. It causes tailbacks and more congestion which increase pollution for pedestrians, cyclists and residents. It's a big problem in large parts of Camden/Islington. It also means that people who are reliant on buses to get to work/school can't predict how long journeys will take. My bus journey to the gym is taking about 50% longer than it used to on some days. Taking bus lanes out and closing stops to put in barely used cycle lanes is another stupid idea.

It may have been a good idea during lockdown when there were far fewer cars on the road but now traffic is back to normal, it's not working.

End of rant.
Just to say, it's the whole point of it. make it slower and more unpleasant to drive & the people who can do without driving will get out of their cars & find more convenient ways to get where they are going, leaving the roads clear for buses, taxis, ambulances & other vehicles with genuine need.
It will also make cycling more pleasant, and thus more popular in the long-run.
The traffic in London just gets slower, the pollution worse and people keep on driving.
For now.

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Re: Traffic 'calming' and pollution

Post by Tessa K » Thu Jun 17, 2021 2:26 pm

Is there any evidence that people who are now cycling to commute (as opposed to for leisure) used to drive cars or did they use public transport?

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Re: Traffic 'calming' and pollution

Post by WFJ » Thu Jun 17, 2021 2:36 pm

Tessa K wrote:
Thu Jun 17, 2021 2:26 pm
Is there any evidence that people who are now cycling to commute (as opposed to for leisure) used to drive cars or did they use public transport?
Even if were true that every cyclist previously used public transport, reducing the required public transport capacity would still be a good thing.

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Re: Traffic 'calming' and pollution

Post by Tessa K » Thu Jun 17, 2021 2:40 pm

WFJ wrote:
Thu Jun 17, 2021 2:36 pm
Tessa K wrote:
Thu Jun 17, 2021 2:26 pm
Is there any evidence that people who are now cycling to commute (as opposed to for leisure) used to drive cars or did they use public transport?
Even if were true that every cyclist previously used public transport, reducing the required public transport capacity would still be a good thing.
Reducing the need would be a good thing before the reduction of capacity.

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Re: Traffic 'calming' and pollution

Post by WFJ » Thu Jun 17, 2021 2:50 pm

Tessa K wrote:
Thu Jun 17, 2021 2:40 pm

Reducing the need would be a good thing before the reduction of capacity.
That's why I said 'required capacity'. People moving from buses/tube to cycling would reduce the need.

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Re: Traffic 'calming' and pollution

Post by IvanV » Thu Jun 17, 2021 5:14 pm

Bird on a Fire wrote:
Thu Jun 17, 2021 1:22 pm
Interesting

My googling took me to the Dept for Transport's London traffic page, yours took you to a blogpost from 2013, and they disagree.

...ETA though as monkey points out, the decline in central London may well have continued, which is good news.
I think actually the data may agree. If you look carefully at the longer time series, it does indicate a drop from 2000 to 2012, though it is a bit hard to discern given the coarse scales.

And I believe what monkey says, that traffic in central London is down. That's why TfL have been able to get away with transferring road space away from motors in central London, though with Westminster Council opposing them most of the way.

Road speeds in central London have been slow in the latter part of the last decade because of more extensive roadworks than usual, including some very disruptive long-term roadworks such as for Crossrail, and the West End scheme that I mentioned earlier - making TotCtRd 2-way, etc. Speeds in other parts of London may well be down if traffic has been growing there.

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Re: Traffic 'calming' and pollution

Post by monkey » Thu Jun 17, 2021 5:51 pm

IvanV wrote:
Thu Jun 17, 2021 5:14 pm
And I believe what monkey says, that traffic in central London is down. That's why TfL have been able to get away with transferring road space away from motors in central London, though with Westminster Council opposing them most of the way.
It's not what I'm saying, it's the DfT :) I just thought it might be useful to see what was going on in Candem and Islington because they were mentioned and we can.

Traffic seems to be up on the outskirts though, which is probably why the London region graph is flat.

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Re: Traffic 'calming' and pollution

Post by Bird on a Fire » Thu Jun 17, 2021 8:11 pm

IvanV wrote:
Thu Jun 17, 2021 5:14 pm
Bird on a Fire wrote:
Thu Jun 17, 2021 1:22 pm
Interesting

My googling took me to the Dept for Transport's London traffic page, yours took you to a blogpost from 2013, and they disagree.

...ETA though as monkey points out, the decline in central London may well have continued, which is good news.
I think actually the data may agree. If you look carefully at the longer time series, it does indicate a drop from 2000 to 2012, though it is a bit hard to discern given the coarse scales.
Yes, that's what I said in the rest of my post ;)

If traffic is falling consistently in central London there must be a heck of an increase in the outskirts to make up for the overall positive trend.
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Re: Traffic 'calming' and pollution

Post by Martin Y » Fri Jun 18, 2021 9:27 am

On the upside regarding demand, "hybrid working" is the new corporate b.llsh.t replacing "hot desking" and if it catches on long-term might significantly reduce commuting. Covid-safe working has revealed an opportunity to get around the problem of not being able to afford nearly enough square feet of London office space for your staff. Instead of stressing them out by making them scramble for desk space every day, you have a more pleasant but too-small office environment and have most of them work from home most days. Sprinkle your policy document with b.llsh.t about it's being "agile" and an "exciting opportunity" and challenge them to "embrace the change" to make it clear that only luddite failures don't.

Every cloud.

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Re: Traffic 'calming' and pollution

Post by jimbob » Fri Jun 18, 2021 10:29 am

Martin Y wrote:
Fri Jun 18, 2021 9:27 am
On the upside regarding demand, "hybrid working" is the new corporate b.llsh.t replacing "hot desking" and if it catches on long-term might significantly reduce commuting. Covid-safe working has revealed an opportunity to get around the problem of not being able to afford nearly enough square feet of London office space for your staff. Instead of stressing them out by making them scramble for desk space every day, you have a more pleasant but too-small office environment and have most of them work from home most days. Sprinkle your policy document with b.llsh.t about it's being "agile" and an "exciting opportunity" and challenge them to "embrace the change" to make it clear that only luddite failures don't.

Every cloud.
Indeed; Covid has accelerated that trend by several years
Have you considered stupidity as an explanation

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Re: Traffic 'calming' and pollution

Post by Tessa K » Fri Jun 18, 2021 10:50 am

IvanV wrote:
Thu Jun 17, 2021 5:14 pm
Bird on a Fire wrote:
Thu Jun 17, 2021 1:22 pm
Interesting

My googling took me to the Dept for Transport's London traffic page, yours took you to a blogpost from 2013, and they disagree.

...ETA though as monkey points out, the decline in central London may well have continued, which is good news.
I think actually the data may agree. If you look carefully at the longer time series, it does indicate a drop from 2000 to 2012, though it is a bit hard to discern given the coarse scales.

And I believe what monkey says, that traffic in central London is down. That's why TfL have been able to get away with transferring road space away from motors in central London, though with Westminster Council opposing them most of the way.

Road speeds in central London have been slow in the latter part of the last decade because of more extensive roadworks than usual, including some very disruptive long-term roadworks such as for Crossrail, and the West End scheme that I mentioned earlier - making TotCtRd 2-way, etc. Speeds in other parts of London may well be down if traffic has been growing there.
It depends on your definition of central London.
The London Plan defines the ‘Central Activities Zone’ policy area, which comprises the City of London, most of Westminster and the inner parts of Camden, Islington, Hackney, Tower Hamlets, Southwark, Lambeth, Kensington & Chelsea and Wandsworth.

For strategic planning, since 2011 there has been a Central London sub-region comprising the boroughs of Camden, Islington, Kensington and Chelsea, Lambeth, Southwark, Westminster and the City of London. From 2004 to 2008, the London Plan included a sub-region called Central London comprising Camden, Islington, Kensington and Chelsea, Lambeth, Southwark, Wandsworth and Westminster. The sub-region was replaced in 2008 with a new structure which amalgamated inner and outer boroughs together. This was altered in 2011 when a new Central London sub-region was created, now including the City of London and excluding Wandsworth. However, districts at the outer edge of this subregion such as Highgate, Archway, Streatham and Dulwich are not generally considered as Central London.
https://en.wikipedia.org/wiki/Central_London

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Re: Traffic 'calming' and pollution

Post by IvanV » Fri Jun 18, 2021 1:11 pm

Tessa K wrote:
Fri Jun 18, 2021 10:50 am
It depends on your definition of central London.
"Your" in the sense of the definition used by the statisticians presenting the data above. I tried to do a little research on this yesterday, and failed to come to a firm conclusion. For most purposes, TfL/Mayor distinguish only Inner and Outer London, which is aligned to borough boundaries. I came across the CAZ, which I'd not heard of before.

I suspect the CAZ might not be the definition of central London they were using for traffic data. The CAZ is really quite small. It includes a detached island around Canary Wharf. It is defined for certain development purposes, and no mentions of it I found are recent. But the reason that made me think it unlikely as a transport definition of central London Is that it excludes Paddington station, but includes areas immediately north and south of it. I would not expect a transport definition of central London to specifically exclude Paddington Station like that when it includes the surrounding area.

I have done work for TfL and been given various customised traffic data extracts by them. Those were defined in terms of congestion charge zone, inner and outer. Though the congestion charge zone was the appropriate area to use for the work we were doing. The congestion charge zone is even smaller than the CAZ. One might imagine them using that as a definition of "central" simply because they have the recording systems in place. But again it excludes areas like Paddington, and even Kings Cross, so seems a bit small.

Whatever, I think we can say that probably the central London definition being used is going to be a pretty small part of Greater London, even if maybe not as small as the congestion charge zone or CAZ. It is probably much less than 10% of the area of Greater London. So a large % reduction in traffic, measured in vehicle-km, in central London, could be equalled or exceeded by a pretty small % increase in traffic.

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Re: Traffic 'calming' and pollution

Post by Imrael » Fri Jun 18, 2021 3:15 pm

Slightly random anecdote, but in the mid 90's I use to drive into the east end of the city to work from Banbury. The reasons for this apparent madness might explain why traffic levels are stubbornly high.

Firstly, it was 3 days a week, so season ticket pricing was useless. Combined with the fact that I mostly had a parking space, economics were marginally in favour of driving.
Driving took a bit longer when things went well, but public transport issues were commoner and worse than road issues. Plus if the traffic stops you have a seat, a roof and a radio.
My public transport journey was at rush hour and uncomfortable, crowded and generally unpleasant enough to make driving very attractive.

Since then both train and car journeys have gone up, but I think/hope the balance has swung train-wards.

Since I'm about to leave the workforce (and wouldnt do a commuter-job for any likely amount of money), its not personal any more, but I think the real problem is the big city employment model. I had hopes that the pandemic would reduce our dependency on lemming-trains into city centre offices every day, but its looking less likely as things have gone on.

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Re: Traffic 'calming' and pollution

Post by dyqik » Sat Jun 19, 2021 1:43 am

Gfamily wrote:
Thu Jun 17, 2021 11:46 am
FlammableFlower wrote:
Thu Jun 17, 2021 10:57 am
There's still the issue of brake and tyre particulate pollution with EVs. It'd be interesting if you had an area that only allowed EVs to compare the levels of pollution to ICE only areas.
Don't EVs often use regenerative braking?, so should be less particulates from brakes at least.
Even hybrids do.

So much so that the rear brakes on Priuses often seize and there's an instruction in the owners manual to perform a couple of emergency stops from 50mph while in neutral a month to prevent this.

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Re: Traffic 'calming' and pollution

Post by Boustrophedon » Sat Jun 19, 2021 9:42 am

dyqik wrote:
Sat Jun 19, 2021 1:43 am
Gfamily wrote:
Thu Jun 17, 2021 11:46 am
FlammableFlower wrote:
Thu Jun 17, 2021 10:57 am
There's still the issue of brake and tyre particulate pollution with EVs. It'd be interesting if you had an area that only allowed EVs to compare the levels of pollution to ICE only areas.
Don't EVs often use regenerative braking?, so should be less particulates from brakes at least.
Even hybrids do.

So much so that the rear brakes on Priuses often seize and there's an instruction in the owners manual to perform a couple of emergency stops from 50mph while in neutral a month to prevent this.
This is a problem with a lot of small FWD cars, most of the weight is over the front wheels and with weight transfer forward on braking the rear brakes do remarkably little. Given a long standing construction and use diktat that states that the front brakes must be the ones to lock up first (regs pre date ABS) under all circumstances, rear brakes on small hatchbacks contribute little very little. It is not surprising they get rusted up.

In the 80s VW had a well advanced prototype three wheeler, FWD with a trailing single rear wheel. They had a hard time justifying the rear brake at all.
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Re: Traffic 'calming' and pollution

Post by Tessa K » Mon Jun 21, 2021 3:25 pm

One thing that worsens the traffic round my way is the lights. They all stay red for ages, let at most three cars through on green, then back to red. This would make sense if one road at the junction was much busier than the other but the road the lights are on has much more traffic in the rush hour than the road the traffic turns into, causing long tailbacks.

These lights have been altered fairly recently, the flow used to be much more even. I wonder if anyone ever monitors the flow once timers have been set?

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Re: Traffic 'calming' and pollution

Post by IvanV » Mon Jun 21, 2021 3:46 pm

Tessa K wrote:
Mon Jun 21, 2021 3:25 pm
One thing that worsens the traffic round my way is the lights. They all stay red for ages, let at most three cars through on green, then back to red. This would make sense if one road at the junction was much busier than the other but the road the lights are on has much more traffic in the rush hour than the road the traffic turns into, causing long tailbacks.

These lights have been altered fairly recently, the flow used to be much more even. I wonder if anyone ever monitors the flow once timers have been set?
TfL is in charge of traffic light, and can adjust the settings of around half of them remotely from a central control centre.

No, I don't think they do detailed local appraisal of the flows once timers or traffic-responsive factors have been set. I think they use central predictive models and rely on those, until complaints come in that what they have done doesn't work.

There is some place on the TfL website where you can complain about specific traffic lights. I have used it a couple of times and got satisfaction. But those were malfunctioning, or seriously misjudged. They were not giving some directions a green at all for several cycles of the light, such that cars eventually think they aren't working and treat them as a give way sign. But I am also aware of places, like you describe, where the timers have only been letting a few cars per cycle in through in some directions for many years, to the extent of producing local gridlock in those directions, while the other directions run freely. But I kind of get the impression it's deliberate: they think that's what you deserve for daring to drive on such backstreets we don't want you on. I also know of some locations where the traffic runs better when the lights break down - and the peds can still cross just as easily. But that might be a bit radical, actually abandoning them. Though I do know a couple of minor junctions where TfL did abandon the traffic lights as they were just too annoying.

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