Air pollution

Articles of interest to the AD community, currently in the news.
gannet
Posts: 178
Joined: Mon Sep 28, 2015 10:23 am

Re: Air pollution

Postby gannet » Thu Dec 01, 2016 2:31 pm

jont- wrote:
gannet wrote:
Horse wrote:Re 20moh. It may be to do with keeping vehicles at constant speed, so reduced acceleration and braking.

possibly, on a course I recently had to do :oops: it was claimed that in one of the southern towns (I forget which one) where they introduced blanket 20mph limits, the average speed has actually increased and congestion is down...

Locals were opposed to the reduction - now fully support it...

Which average? Any mean is going to be horribly skewed by congestion at rush hour, and it's entirely believable a lower limit improves things there. But what about all the time stolen from road users in the quieter parts of the day?
And congestion in surrounding areas? Overall traffic numbers (have people simply gone elsewhere? That only works until everywhere else is also just as bad, and we move to 10mph limits :roll: ).

I'd love to be able to back it up with documentation - but none was offered, and it was said in passing to illustrate a point.

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Horse
Posts: 1965
Joined: Mon Sep 28, 2015 9:20 am

Re: Air pollution

Postby Horse » Thu Dec 01, 2016 2:45 pm

jont- wrote:
gannet wrote: it was claimed that in one of the southern towns (I forget which one) where they introduced blanket 20mph limits, the average speed has actually increased and congestion is down.

Any it's entirely believable a lower limit improves things there. But what about all the time stolen from road users in the quieter parts of the day?
And congestion in surrounding areas? Overall traffic numbers (have people simply gone elsewhere? That only works until everywhere else is also just as bad


Haven't you got three things mixed up:
- Free (er) flowing steady traffic
- Displacement of traffic onto other route - not the same as altering average flow speed
- 'Stolen' time? Really?
My own views. For better or worse :)

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jont-
Posts: 1000
Joined: Mon Sep 28, 2015 7:12 am
Location: Flatlands

Re: Air pollution

Postby jont- » Thu Dec 01, 2016 2:54 pm

Horse wrote:- 'Stolen' time? Really?

If you're making me travel more slowly than is safe, you're stealing my time. Or should I be using the extra time in my car for things like making phone calls? :hit:

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Horse
Posts: 1965
Joined: Mon Sep 28, 2015 9:20 am

Re: Air pollution

Postby Horse » Thu Dec 01, 2016 5:29 pm

From the particular roads branded '20' around here, it's unlikely you'd get up to 30 for long and if you were it wouldn't qualify as 'safe'.

And if you save fuel, that will save you time on fuel stops ;)
My own views. For better or worse :)

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Strangely Brown
Posts: 575
Joined: Sun Sep 27, 2015 8:06 pm
Location: Sussex

Re: Air pollution

Postby Strangely Brown » Thu Dec 01, 2016 6:18 pm

It can't have been Brighton as the traffic speeds now (post blanket 20) are just the same as before (pre blanket 20). Everyone ignores them.

ratty
Posts: 74
Joined: Sat Dec 19, 2015 6:38 pm

Re: Air pollution

Postby ratty » Sat Jan 28, 2017 11:45 pm

gannet wrote:
Horse wrote:And I bet you went along expecting to learn nothing :)

open mind me...

I learnt nothing that has fed back into my driving though...



Not even how to avoid being caught again ?

gannet
Posts: 178
Joined: Mon Sep 28, 2015 10:23 am

Re: Air pollution

Postby gannet » Mon Feb 06, 2017 1:49 pm

ratty wrote:
gannet wrote:
Horse wrote:And I bet you went along expecting to learn nothing :)

open mind me...

I learnt nothing that has fed back into my driving though...



Not even how to avoid being caught again ?

avoiding being caught is easy - don't speed? ;)

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AndyP
Posts: 162
Joined: Sat Feb 11, 2017 9:38 am
Location: Bath/Bristol

Re: Air pollution

Postby AndyP » Fri Feb 17, 2017 9:10 am

Recent evidence has shown that 20 mph limits now increase pollution for local residents.

The basic conclusion was that vehicles could be in a lower gear [higher revs more output] or remained in the area/location for longer thereby polluting more.

Previous evidence was that out of 'rural' 'town' and 'motorways' pollution 'in car' was worse on a motorway as you were constantly driving through a 'tunnel' of exhaust fumes less in town as it had time ti rise and obviously best in the country.

Other evidence is the obvious fact that cars are incredibly less polluting these days.

A previous VOLVO model had a 'Catalytic' radiator and the air coming from the back of the car was cleaner than what went in. However this 'expensive' item only benefited those following you so was not fitted.

Sorry no links I just gather and remember all this useless stuff!!
It is not WHAT you drive, BUT:-- the WAY that you drive it.
It is not HOW fast you drive, BUT:-- HOW you drive fast.

Cheers Andy

sussex2
Posts: 532
Joined: Mon Sep 28, 2015 11:43 am

Re: Air pollution

Postby sussex2 » Fri Feb 17, 2017 3:03 pm

I've posted this before but here goes again:

A few years ago the provincial government in Barcelona imposed an 80kph limit on the city's many ring roads. The idea of the scheme was to reduce pollution and casualties.
It soon became apparent that pollution had increased as indeed did casualties and especially fatalities.
The scheme was replaced by a city wide electronic speed control system with varying speed limits. A similar system exists in many cities as we know. The pollution and the casualties dropped below the pre 80kph level.

It happens that the city government also used the varying speed limits to introduce average speed control cameras for the entire (large) network - everything comes at a price :)

martine
Posts: 724
Joined: Mon Sep 28, 2015 8:26 am

Re: Air pollution

Postby martine » Fri Feb 17, 2017 5:07 pm

AndyP wrote:Recent evidence has shown that 20 mph limits now increase pollution for local residents.

The basic conclusion was that vehicles could be in a lower gear [higher revs more output] or remained in the area/location for longer thereby polluting more.

Previous evidence was that out of 'rural' 'town' and 'motorways' pollution 'in car' was worse on a motorway as you were constantly driving through a 'tunnel' of exhaust fumes less in town as it had time ti rise and obviously best in the country.

Other evidence is the obvious fact that cars are incredibly less polluting these days.

A previous VOLVO model had a 'Catalytic' radiator and the air coming from the back of the car was cleaner than what went in. However this 'expensive' item only benefited those following you so was not fitted.

Sorry no links I just gather and remember all this useless stuff!!

Welcome Andy. Love your signature.

Did you know the extensive 20 limits in Bristol are being reviewed on the instruction of the new Mayor?
Martin - Bristol IAM: IMI National Observer, Group Secretary, Masters (dist), DSA: ADI, Fleet, RoSPA (Dip)


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