Is 'Quiet' tarmac more economical?

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Mactech

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I think we all agree that the quiet road surfaces on some new roads have benefits for those living next to busy roads and for drivers enjoying a much quieter car on those stretches. Going from a old concrete dual carriage way to quiet tarmac is like hitting the mute button in most cars. It's widely agreed that the most intrusive noise above 50mph is not wind or mechanical, but tyre roar.
All new tyres have a decibel rating, but this is 'drive by' noise level and not what we hear in the car.

My question is, are these roads more economical? Studies have shown that in many cases there are the most cost effective way of reducing noise pollution when compared to acoustic fences and cuttings.

But I think there is another benefit. Reduced fuel consumption for drivers!:eek:
I have often noticed a consumption reduction of around 2% on the quiet tarmac.
Same day, car, conditions, elevation, speed etc. but always better on the new tarmac....in either direction:D
Using a little 'man maths'...if a typical car takes about 35bhp to push it along at 70mph, then 2% saving represents about 0.7 bhp or about 520watts.
Not an unbelievable figure given the huge noise created by 4 very inefficient sound transducers....and that's before we talk about any rolling resistance differences!
When doing the diesel land speed record I became aware of 'spray drag'. It's the a phenomenon on dusty surfaces where the drag increases due to the wake of the car being in a denser 'fluid'. In our case on the salt flats, it was air with a whole bunch of salt particles thrown into it.....

So can we have a more peaceful and economical time on quiet tarmac?:dk:
Just curious!:eek:
 
On a related note I've found tyres make a big difference to the noise, which tyres have members found the quitest? I'll start with mine - goodyear efficientgrip, quiter then the Kumho's the car came with when purchased (used).
 
I'm sure Scotty would chime-in about the Laws of Physics.....all that noise has gotta come from somewhere, and that somewhere is your fuel consumption...
 
Now when someone says "Good Question" you just know you are going to get a carp answer. And that Mactech is a very good question.

Did I read somewhere that "quiet road surfaces" have old tyres shredded and incorporated the mix of surfacing used. Which is supposed to reduce the rolling resistance of rubber on rubber as it were. Therefore giving better MPG and quieter inside and outside ambient noise level, or words to that effect.

CHEERS
 
Yes, tyres make a big difference;)
Must compare new with new as the bigger tread depth not only give a better ride quality, but also a noise damper effect to stop the tyres 'ringing'.
Worn tyres will almost always be louder.
 
Looking at it from another angle, I'd say that quiet tarmac makes you drive faster without realising whereas those noisy sections (parts of the M180 spring to mind) seem to slow me down to save my eardrums.
 
Our last house was near a busy 40mph road. The difference in noise after resurfacing with a quiet material was astonishing.... right up until they put the cats eyes back in! Dubadubadubadub....which was unnecessary as it is a well lit stretch of road. :doh:
 
Yes! All good stuff and there is plenty out there on tyres, roads and noise.
Not found anyone connecting the efficiency of the quiet roads with the vehicle user.
We all like the quiet roads provided they can give the grip and wear rates of conventional roads, but is there another factor which could be promote these?

It's normally a government mandate which accelerates research in these areas....err ...like emissions :confused:
VW group need not apply:doh:
 
Looking at it from another angle, I'd say that quiet tarmac makes you drive faster without realising whereas those noisy sections (parts of the M180 spring to mind) seem to slow me down to save my eardrums.

I find wearing ear plugs on the bike has a similar effect....I really have to watch the speedo to remain (semi) legal:eek:
 
Looking at it from another angle, I'd say that quiet tarmac makes you drive faster without realising whereas those noisy sections (parts of the M180 spring to mind) seem to slow me down to save my eardrums.

I've always maintained that one way to discourage lane-hogging on motorways and dual carriageways would be to have different grades of tarmac in each lane, with the quietest smoothest tarmac on the inside lane and the roughest in the outside lane. Lanes in between would have proportionately graded smoothness. That way, overtaking drivers would be actively and audibly encouraged to pull back into the inside lanes as soon as their overtaking manoeuvre is completed.
 
Interesting. I'd never considered the economies before other than reports from 15 to 20 years ago saying that the quiet road surface was too expensive to be used everywhere. The cost of the alternative roadside sound shields wasn't mentioned at the time. I agree that there have to be user cost benefits, even if only small. But these equate to less energy usage so must be good for everyone.

It seems that quieter road surfaces have a shorter life, but even then are more economical than roadside sound control systems. The downside that I can see is that more frequent resurfacing results in more roadworks with their inevitable problems. I doubt that this user cost has been factored into the economy calculations, but perhaps they'd be balanced out by the individual savings already mentioned.

What also has to be considered with the quieter road surfaces is their safety characteristics. Are they as good at removing surface water, how do they perform at lower and higher temperatures, what comparative effect do they have on braking distances and cornering tyre grip? And do we need to consider an inevitable consequence of quieter roads being that people may find that they're generally driving faster because of the reduced noise levels inside their vehicles?
 
jdrrco said:
I've always maintained that one way to discourage lane-hogging on motorways and dual carriageways would be to have different grades of tarmac in each lane, with the quietest smoothest tarmac on the inside lane and the roughest in the outside lane. Lanes in between would have proportionately graded smoothness. That way, overtaking drivers would be actively and audibly encouraged to pull back into the inside lanes as soon as their overtaking manoeuvre is completed.
There's a stretch of the A1 just south of Peterborough that's very much like this. Four lanes with the inside one or two being much quieter. I can't say I've noticed more drivers heading back to the inside lanes - perhaps the outer lanes aren't noisy enough!
 
As PaulG said, noise is energy. So if your engine is pushing the car along at 70 and producing 80 dB it's using more energy (fuel) than doing the same speed and producing less noise.

But I suspect the impact on mpg would be tiny.
 
I'm sure Scotty would chime-in about the Laws of Physics.....all that noise has gotta come from somewhere, and that somewhere is your fuel consumption...

Aye! It's a question Jim....but not as we know it!

The smoothness of the road has an effect on efficiency, maybe that is partly the reason I've seen an economy improvement? In an extreme case, the dampers on a rally car are too hot to touch after just one stage.

Energy is very good at playing transformers!

The heat dissipated from the brakes of Bentleys Le Mans cars in the race was enough to heat a typical British house in winter.....all winter!
Things are a little better now with the hybrids, but I suspect you'd still want a mild April;)
 
This would give further creedence to the theory. It links low rolling restance tyres and road surfaces. For those seeking a few extra MPG it would appear tyres labelled as low rolling resistance and low sound levels might be worth seeking out.
https://www.sciencedaily.com/releases/2016/09/160928083212.htm

from

https://www.sintef.no/en/latest-news/using-ev-tyres-to-counter-traffic-noise/

http://www.leo.mech.pg.gda.pl/sites...s/Program LEO seminar, Oslo 2nd June 2016.pdf

possibly demonstrated by BMW's i3 TYRE the Bridgestone Ecopia EP500 175/60 R19 86Q @ 69dB !!!
https://www.cnet.com/roadshow/news/tire-tech-the-bmw-i3s-bridgestone-ecopia-ep500s/

Bridgestone Ecopia EP500 175/60 R19 86Q * - mytyres.co.uk

1-B-B-69-2.png
 
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Great find, thanks:D

I'm glad my hunch and quest for efficiency is based in some science and that I'm not going completely mad:cool:
 
I would not be surprised if it turned out that quiet tarmac is also safer - that noise pollution causes fatigue is well established.
 

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