Traffic report said a couple ramps closed at the M25 / A3 interchange roundabout due to over gritting.
I have never heard a report of this type before.
The report said something about "shingle?" effect.
Anyone else come across this?
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Well shingle is used to kill speed on run-offs in F1, but I can't imagine they put that much down!
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Dozy twits in the Highways Agency.
Below about minus 2 degrees centigrade salt stops working in the way intended. And when it is combined with plenty of grit the effect you get is like marbles. Salt attracts moisture and makes the road wetter than it might otherwise be. At the present temperatures the road have effectively been freeze-dried - leaving ice crystals on the road surface. If those ramps are curved and you would normally expect to drive them at 50mph...you may get a nasty surprise.
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I've just seen the result of a nasty surprise as a result of what happens when a road is gritted and then it hits -9 overnight. It was -6 when I passed the written off MX5.
It appeared the driver had left a roundabout, given it too much on the exit before straightening the wheels, back end stepped out, hit fence with one end, went through 180 hit fence with the other end then came to a standstill.
He was lucky not to go through the fence and end up in the river about 30 feet below.
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I've just seen the result of a nasty surprise as a result of what happens when a road is gritted and then it hits -9 overnight. It was -6 when I passed the written off MX5. He was lucky not to go through the fence and end up in the river about 30 feet below.
I was just thinking you'd seen the same broken MX5 as me this morning, on the Basingstoke ring road, until you mentioned the river, must be a different one; not a good day for RWD I suppose :-/ ( without wishing to start the whole debate on that subject!)
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Dozy twits in the Highways Agency.
No - Dozy drivers not adapting to the road conditions. We have winter every year!
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Winter can`t be expected to impact at all on the `right to make progress` thought ;-) . Its likely no win for the Agency. Some would want to sue it for excess salt and spin offs - others for closing the slip road and `taking their time` Others still may just want to sue - but cant figure out yet how to. Perhaps even their partner for being in the car and not being heavy enough to give more traction to the wheels.
I`m off to live abroad - if I can ever muster the effort..
(another humour attempt - by the way ;-)
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The report said something about "shingle?" effect. >> Anyone else come across this?
I once had to stop quickly on a thickly-salted surface, and the car skidded almost as if it was on snow.
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>> The report said something about "shingle?" effect. >> Anyone else come across this?
Yes - It happens when roads have been freshly gritted and there hasnt been enough traffic to "blow" the grit off the road.
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I think the highways agency round this way have some issues.
Last week they overgritted the M3 between fleet camberly and lightwater. The air was like a sahara dust storm for hours and the traction was appaling if you went off the tramlines.
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Sounds like people who never venture north of the M4 (or is it Watford) have real problems with gritted roads. :-)
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Years ago the gritters seemed to fire rock salt like pea gravel out of the back. Are there a variety of grades now? because there is often a very light coloured fine stuff spread - very sparingly - on our local `danger of ice` spots.
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We have a very simple system here in Sweden. Each autumn they send a map of the area showing which roads they salt, and how often, but only down to -5. Below that there's nothing. This is on most major roads and motorways. For smaller roads it shows which ones wll be ploughed, and at what depth the snow must be before it starts. If a road isn't on the map, then it will just be ploughed as and when. Main roads are ploughed by the council, but all the others are done by private contractors, often farmers. They are given a plough and a retainer, then paid everytime they do out. This way, the whole area can be covered almost as soon as it snows.
Of course, it would never work in the UK, as customs and excise would be after the farmer for using red diesel, bus loads of officials would have to be employed to make sure the farmers are doing what they have billed for, the ploughs would get stolen, and they'd have to have at least a billion pound of 3rd party liability cover, which would cost more than they're ever likely to earn. Not to mention the training required, health an safety assesments, and even more officials to oversee this.
The gritters here just spray a salt solution with no grit. The ploughed roads sometimes get a sprinkle of gravel. The nearest town to me does not use any salt at all, due to problems with runoff into the lake. So everyone knows exactly where they stand, and what sort of surface they're likely to be driving on.
Over gritting, undergritting, black ice, snow over ice - no-one mentions it or even seeks to blame anyone for adverse conditions. The attitude is, if you're too stupid to work out it's cold out there and therefore there may be slippery roads, then you deserve everything you get.
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if you're too stupid to work out it's cold out there and therefore there may be slippery roads then you deserve everything you get.
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Got it in one!
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>>Below about minus 2 degrees centigrade salt stops working in the way intended.
I understood it was effective down to about -5C, but today I was told they're mixing it with molases which makes it efective to -20C.
Any experts out there?
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"Any experts out there?"
Nope; but I remain convinced that (wet) salted roads, while much less slippery than icy roads, are much more slippery that normal, unfrozen, unsalted roads.
Salt is slippery stuff - and also seems to "attract" moisture so that a salted road is wetter than an unsalted road.
Made sense in my head - not sure it does above!!!
Phil
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That does make sense, Phil. If the weather is very dry but cold, a salted road will be wetter - salt is hygroscopic and absorbs water. That's why the roads have been sopping wet in the mornings lately despite no rain - a lethal combination of slippery salt/water/and possibly ice mixture. In cold dry conditions, it really isn't worth salting, as it makes conditions worse not better. I don't know why local authorities can't act based on a proper assessment of temp/humidity conditions and adjust accordingly. As someone above has also commented, there's no point in salting at very low sub zero temperatures anyway.
There are conditions when it's beneficial to salt, for example, a wet road after rain, with clearing skies and plunging temperatures, or snow at around 0 Celsius.
Ask any biker how slippery the main roads are right now with the salt slick. Minor roads are much dryer and grippier. I imagine a lot of people have a false sense of security as well.
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.. mixing it with molases which makes it efective to -20C. >>
bbs.scoobynet.com/scoobynet-general-1/399085-animal-fat-road-salt-grit
-beware-2.html
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There's enough salt around Surrey's roads now to last years. >:-(
Making me wince thinking about the atom-thick layer of paint protecting the bike's frame. The less said about the front calipers the better, too.
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"enough salt around Surrey's roads now to last years. >:-("
Agree; driving to Midlands this aft from Bracknell area it was noticeable that trucks were throwing up a dustcloud of salt on the M40. Roads were dry so salting was a bit pointless. On the other hand, if there had been a bit of snow/rain on the very cold surface it could have been lethal. Heard on radio that M32 was closed today because of ice - guess the gritters are "damned if they do: damned if they don't". Excess salting better than none.
As a pedestrian at times yesterday and today can I add that footpaths have been lethal - very, very icy and no grit/salt. Feel sorry for the older folks trying to negotiate them(and if they are older than me they are very old!)
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What gets me is that, when the temperature drops, motorists are advised to only travel if absolutely necessary.
Just how many seem to think it's absolutely necessary to go into work, or drop of the kids at school, or a morning trip to Asda....
And how many drivers ever go for training in how to drive on icy roads?
I'm beginning to rant................!!!
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