Skid risk / Slippery road signs
Discussion
I've been having some thoughts whilst driving around over the past few days as to the employment of skid risk signs; primarily, wondering what the conditions / requirements are for their installation, as I've seen a few in places with little in the way of obvious cause - A quality surface, no nearby farm entrances (And the mud entailed), and no visible environmental disposition to skid risks (i.e. particularly exposed to icing)
In the same vein, I was wondering about signposting for wild animals - Surely there's got to be some level of selection to highlight an additional risk over a certain given distance of road, i.e. a particularly high incidence of animal / car incidents?
In the same vein, I was wondering about signposting for wild animals - Surely there's got to be some level of selection to highlight an additional risk over a certain given distance of road, i.e. a particularly high incidence of animal / car incidents?
I don't know the official reasons for their deployment but I have seen one where a seasonal spring would leak water across a road in winter now and again, that froze causing ice when there was no other ice around.
Also for about 100Metres around where I live there is frost/ice when beyond that distance the temperature is +2C... i.e. a frost pocket. Maybe frost pockets get these signs as they are markedly different road conditions from elsewhere.
Just guessing though.
Also for about 100Metres around where I live there is frost/ice when beyond that distance the temperature is +2C... i.e. a frost pocket. Maybe frost pockets get these signs as they are markedly different road conditions from elsewhere.
Just guessing though.
Have a look at that, see if any use.
Although HD28 now seems to have been superseded by CS228 version 2 (google it as a pdf and i can't link)
I thought they could only really be used for a maximum length of time as if it was a known issue i thought a highway authority had a duty to correct it and bring it back up to standard for not skidding.
I'm sure someone will correct me on that though
Although HD28 now seems to have been superseded by CS228 version 2 (google it as a pdf and i can't link)
I thought they could only really be used for a maximum length of time as if it was a known issue i thought a highway authority had a duty to correct it and bring it back up to standard for not skidding.
I'm sure someone will correct me on that though
speedyguy said:
Have a look at that, see if any use.
Ah, Good pointer - Looking at HD28 Now; I'll have to see if I can find the updated document.The level of process behind the installation of the signs is, as expected rather impressive - I think I'll pay them more heed in future (Not to say I've discarded them in the past!)
ETA: https://www.standardsforhighways.co.uk/prod/attach...
That link might work for others who are interested.
I note the requirements specify an annual review of existing skid risk signage too.
Edited by Haltamer on Wednesday 29th September 23:57
Each road/section has what you call an Intervention Level. Which is a Category and a corresponding numeric value. As found in CS228, used to be HD28/15.
So high risk areas will have a higher IL, say sharp bends on NSL roads, approach to Ped crossing etc will generally be given the highest value of 0.55. Where as Dual CW will have the lowest of 0.3. Most common is 0.4.
Each year a local authority will have a SCRIM survey undertaken on their network to get the "Skid" level of a road. This is generally not on 100% of their network each year, most do a 1/3 of their network each year for budget reasons. 100% of their A, B and a selection of C roads will be done over a 3 year period.
Each Local authority has a different SCRIM policy on how they treat the difference between the Skid resistance & IL value. But if a Skid value is below the IL the site needs to be investigated and action recommended to bring the surface back within IL limit or see if any other action needs to be taken (Signs, road markings, layout change, IL change etc)
So usually the temp signs are put out if they know the Skid level is below IL but haven't taken any action to rectify the issue, again its usually down to budgets. Permanent skidding signs are usually put up when you've got a section with a higher accident rate or the surface suffers with polishing and fatting regardless of treatment, this is usually in areas either high speed heavy traffic flow or under tree cover.
So high risk areas will have a higher IL, say sharp bends on NSL roads, approach to Ped crossing etc will generally be given the highest value of 0.55. Where as Dual CW will have the lowest of 0.3. Most common is 0.4.
Each year a local authority will have a SCRIM survey undertaken on their network to get the "Skid" level of a road. This is generally not on 100% of their network each year, most do a 1/3 of their network each year for budget reasons. 100% of their A, B and a selection of C roads will be done over a 3 year period.
Each Local authority has a different SCRIM policy on how they treat the difference between the Skid resistance & IL value. But if a Skid value is below the IL the site needs to be investigated and action recommended to bring the surface back within IL limit or see if any other action needs to be taken (Signs, road markings, layout change, IL change etc)
So usually the temp signs are put out if they know the Skid level is below IL but haven't taken any action to rectify the issue, again its usually down to budgets. Permanent skidding signs are usually put up when you've got a section with a higher accident rate or the surface suffers with polishing and fatting regardless of treatment, this is usually in areas either high speed heavy traffic flow or under tree cover.
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