dodgy science - a pet peeve

by dbroada Tue Feb 07, 2017 2:51 pm

I live in Croydon and last week we had a council notice through our doors outlining a proposed borough-wide 20 mph speed limit. Not quite all road as ours will remain at 30. This despite several school children having been hit by cars while trying to cross the busy road and a crossing being denied by TfL as the average speed is too high!

Today I had a leaflet through my door outlining why I should object to the 20 mph limit to the council.

I know how tedious it is to drive through Brighton at 20 but I'm not overly fussed one way or the other. What I do object to is what I see as dodgy science in the leaflet.....

"Slowing traffic to 20 mph means more vehicles on the road." - How does that work? The same amount of traffic on the road for longer, yes, but do more people actually take their cars out because of the lower speed?

"Slower traffic means worse fuel economy and worse air quality." - Here I can't comment on the "facts" but genearallyI have noticed that the slower you drive the less hard you have to brake and consequently the less fuel used over and above any not used by driving slower. And again I would expect air quality to be a byproduct of the fuel used, not how you choose to disperse it.

The leaflet then goes on to say some sensible things but I'm so insensed by trying to win us over with a statement I don't believe they have lost me.

End of today's grumps - for now.

by Gromit Tue Feb 07, 2017 3:05 pm

That's not dodgy science Dave.

It's a clear indication that with their IQ plus 30 pence they still couldn't afford a bag of crisps! shrugg

by rogerblack Tue Feb 07, 2017 4:15 pm

I'm never sure which is the more worrying scenario - that they've used this knowing it to be wrong just to try to win their aims or that they actually believe it to be true.

The shockingly low level of knowledge portrayed by so called celebrities from reality TV shows when they compete in charity quiz programmes scares me if it is typical of current levels of education.

rolleyes

by dbroada Wed Feb 08, 2017 11:19 am

I expected a torrent of people pointing out that I was wrong. I'm happy to have two in general agreement.

I tend to spend too much time on Facebook and see so much of this, words not used in a way I am familiar with. I know about clickbait but I have a cousin who falls for it constantly. He is forever posting links to quizzes that "only 3% of the population will get more than 2 questions right". Amazingly he always gets 80-100% correct!

Another annoyance is "ONLY 83% of people can do this, are you one?". ONLY and 83% don't belong together. Along with up to 50% or more.

And finally, I am reminded of a radio show called Radio Active.They ran a competition broadly along these lines.....

What is the capital of France?
Is it:

a) Paris
b) Two Fat ladies
c) a Rhododendron

Send your answers on a postcard to:

Paris is the capital of France competition
PO Box 57

by rogerblack Wed Feb 08, 2017 11:47 am

But of course all of those choices are wrong.

The capital of France is
.
.
.
F

Whistle1

by Gromit Wed Feb 08, 2017 12:56 pm

rogerblack wrote:But of course all of those choices are wrong.

The capital of France is
.
.
.
F

Or it might be €uros snigger

*********************************

And what about the downright lies!!

Just one example - all the hair restorer shampoos on the market. If it was possible to restore hair loss, would Bill Gates be going bald??!! shrugg

by Askit Wed Feb 08, 2017 3:23 pm

As we're in the midst of being regaled by "fake news", it hardly surprising that folk churn out "facts" which bear no scrutiny. Several people may pick up the anomalies in the 20mph protest paper, many more will no only take it in, but quote the information to others as gospel twiddle_thumbs

.

by pablo Wed Feb 08, 2017 9:58 pm

just thinking about your musings and

a) if everyone drives more slowly surely that means it takes longer for your journey so there are more vehicles on the road.

b) and if the vehicles take longer to get there there are more traffic jams meaning worse fuel economy and more pollution.

or is this twisted logic???? scratch head

by Gromit Wed Feb 08, 2017 10:07 pm

pablo wrote:just thinking about your musings and

a) if everyone drives more slowly surely that means it takes longer for your journey so there are more vehicles on the road.

No. It means the same number of vehicles are on the road for longer - and if they hit anyone or anything they don't clout it quite so hard!!

b) and if the vehicles take longer to get there, there are more traffic jams meaning worse fuel economy and more pollution.

More traffic jams? Why would driving slowly create traffic jams? The slower you drive (within obvious reason) the less fuel you use, so the nett result will be much the same.

or is this twisted logic????

Yep. I reckon it is.

by rogerblack Wed Feb 08, 2017 10:54 pm

If slowing down traffic causes more traffic jams, why do variable speed sections of motorways e.g. M42 around Birmingham, use temporary lower speeds as a means to ease traffic queues and congestion at busy times?
think_smiley_46

by dbroada Wed Feb 08, 2017 11:42 pm

rogerblack wrote:If slowing down traffic causes more traffic jams, why do variable speed sections of motorways e.g. M42 around Birmingham, use temporary lower speeds as a means to ease traffic queues and congestion at busy times?

That is due to a phenomenon known as "shock wave". If you drive fast and the vehicle in front slows down suddenly, you brake harder than necessary causing the car behind etc. etc. At lower speeds people tend to brake in a much more appropriate time and tempo keeping the traffic flowing better.

by -mojo- Thu Feb 09, 2017 1:13 am

In my experience, the fundamental flaw with 20MPH speed limits is that they are simply universally ignored. The centre of my town is a 20MPH zone, and nobody takes the slightest bit of notice of the speed limit.

That's not to say that I disagree with the science that supports a reduction in speed - it's a fact that the kinetic energy of a vehicle increases with the square of speed. But what purpose does a law serve if it is observed by nobody?

(I should add that I personally don't mind traveling at 20MPH in areas where there is specific extra risk, such as adjacent to primary schools, but I ~do~ mind being tailgated all the time while doing so.)

by Askit Thu Feb 09, 2017 8:16 am

Mojo, I stick to speed limits (including the 20mph ones around us) and regularly get tailgated at 30mph. There will always be somebody who has to get somewhere faster than you are travelling.

How often, when you're driving at a reasonable speed and get overtaken by someone in a hurry, do you meet them again at the next set of traffic lights, roundabout or road junction.

by dbroada Thu Feb 09, 2017 10:03 am

Askit wrote:Mojo, I stick to speed limits (including the 20mph ones around us) and regularly get tailgated at 30mph. There will always be somebody who has to get somewhere faster than you are travelling.

As I said in my first post, I live on an A road with a 30 mph limit and you WILL be tailgated if you drive along there at 30. There are parts without houses but the majority of the road is residential with houses that don't have front gardens so it is very easy to imagine a child running straight out (ok, between the parked cars).

I too am one of those people who are happy to stick to the posted limit and while I find the 20 tedious I do stick to it.

How often, when you're driving at a reasonable speed and get overtaken by someone in a hurry, do you meet them again at the next set of traffic lights, roundabout or road junction.

When I lived in Germany our town had a ring road with a "grüne Welle" (green wave) where all the green traffic lights synchronised at 50kph. If you passed through one green light and kept to 50 you would meet all the other green lights for the entire length of the ring road. At least you would do were it not for all the people who would drive faster than 50 and have to stop at the next set of red lights blocking your way.

by rogerblack Thu Feb 09, 2017 11:19 am

Bath Road Slough has a long stretch of linked lights at 30 mph

by dbroada Thu Feb 09, 2017 1:03 pm

rogerblack wrote:Bath Road Slough has a long stretch of linked lights at 30 mph

Is it labelled as such or only common knowledge? The Germany towns are quite obvious giving you the speed that will work - not that many people heed the advice.

by willy eckerslike Thu Feb 09, 2017 8:40 pm

dbroada wrote:

When I lived in Germany our town had a ring road with a "grüne Welle" (green wave) where all the green traffic lights synchronised at 50kph. If you passed through one green light and kept to 50 you would meet all the other green lights for the entire length of the ring road. At least you would do were it not for all the people who would drive faster than 50 and have to stop at the next set of red lights blocking your way.

I bet "all the people who would drive faster than 50" weren't German. When we lived in Germany rules were made to be obeyed ! hugegrins

by bikeralw Thu Feb 09, 2017 9:37 pm

You come out of a shop, the sun has vanished and it's started sudden torrential vertical rain, you have to get back to your van across 500 yards of open ground. You want to arrive as dry as possible, do you run or walk?

by Kingham Thu Feb 09, 2017 11:02 pm

pablo wrote:just thinking about your musings and

a) if everyone drives more slowly surely that means it takes longer for your journey so there are more vehicles on the road.

I'm looking at that one from a different perspective, if 5000 cars set out on the commute to work on a Monday when the speed limit is 30mph, those same cars will need to get to work the following Monday, after the new limit of 20mph has been imposed.

The speed limit has no direct correlation to the number of cars using the road.

by Kingham Thu Feb 09, 2017 11:06 pm

bikeralw wrote:You come out of a shop, the sun has vanished and it's started sudden torrential vertical rain, you have to get back to your van across 500 yards of open ground. You want to arrive as dry as possible, do you run or walk?

Is there a pub next door to the shop drinksallround

by rogerblack Fri Feb 10, 2017 4:06 pm

Wargenwolf wrote:
bikeralw wrote:You come out of a shop, the sun has vanished and it's started sudden torrential vertical rain, you have to get back to your van across 500 yards of open ground. You want to arrive as dry as possible, do you run or walk?

Is there a pub next door to the shop

I like the way you think, Wargenwolf! allthumbz

by TravelKat Fri Feb 10, 2017 4:30 pm

The lane we live on used to have a 30mph speed limit; a few years ago it was reduced to a 20mph speed limit. When it was 30mph people ignored it, since it's 20mph we're convinced they drive even faster! Apart from a few, including us, the number of people who keep to that limit can be counted on one hand.

by chrisvesey Fri Feb 10, 2017 5:21 pm

rogerblack wrote:Bath Road Slough has a long stretch of linked lights at 30 mph

,
I remember the linked 30 mph lights in slough, also if you drove at 60 mph you would get straight through,
Chris

dodgy science - a pet peeve

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