A35 Sinkhole

[Herned]

Despite these well placed signs, one or two managed to turn on to the e/bnd A35, at both ends of the old road, caravans and even lorries..... Shurely shome mishtake.....

I'm not surprised. I cycled along a road that is closed for works the other day, signed clearly and regularly from several miles back. There was a constant stream of cars driving up to the blockage and turning round

[SteveA30]

It is just a case of automated systems running the show, instead of people. It was switched from Unplanned to Planned and so the standard system kicked in. Div routes miles away from the site. The obvious route which was used when categorised as Unplanned is ditched. HE traffic had the A35 yesterday morning. Since it became Planned, it isn't mentioned. This inflexibility affects so many companies and organisations nowadays. Automation may be useful for the owners but for the user -the public- it is remote from reality.
Maps today are not showing any traffic into Puddletown from the A354 but, the short bit of A35 to Troy Town is still closed. Will have to take a look. Is A354 traffic really being sent back east along the A35 to Bere Regis? I wonder if Sat Navs can work around this and find the logical route. Taking the old A35 from the B3390 Affpuddle neatly avoids all the nonsense, taking you out at the Stinsford end, which is my route...

[WHBM]

Speed limit is a minor worry. If there are no hardened crossovers (which there aren't) how are they going to magically appear?

Um ... what's this I can see ? Seem to remember it from the construction.

https://www.google.com/maps/@50.7504248 ... 312!8i6656

https://www.google.com/maps/@50.7505366 ... 384!8i8192

[Micro The Maniac]

Speed limit is a minor worry. If there are no hardened crossovers (which there aren't) how are they going to magically appear? TBH your first sentence is probably correct

It is, surely, not beyond the wit of man, or indeed HE, to create a temporary crossover that will last a few days/weeks/months while they fill in a hole?

Any risk assessment would, surely, show that sending vehicles along unsuitable roads (the fact that the villages were bypassed) is a greater evil?

[RichardA35]

Speed limit is a minor worry. If there are no hardened crossovers (which there aren't) how are they going to magically appear?

Um ... what's this I can see ? Seem to remember it from the construction.

https://www.google.com/maps/@50.7504248 ... 312!8i6656

https://www.google.com/maps/@50.7505366 ... 384!8i8192

I know where they are - I built them - the response was in reply to the instant 100yard contraflow

[WHBM]

I know where they are - I built them - the response was in reply to the instant 100yard contraflow

Sure . About 1990 ?

And I think you would only need one, the other end can just run out at the end of the dual. About a mile of cone dividers.

It's just where THIS happened to me, Christmas 2004, in my old Jag

viewtopic.php?f=1&t=38300&p=946993&hili ... nt#p946993

[RichardA35]

I know where they are - I built them - the response was in reply to the instant 100yard contraflow

Sure . About 1990 ?

And I think you would only need one, the other end can just run out at the end of the dual. About a mile of cone dividers.

It's just where THIS happened to me, Christmas 2004, in my old Jag

viewtopic.php?f=1&t=38300&p=946993&hili ... nt#p946993

That crossover is on the Puddletown bypass section c. 1997-1998 (Balfour Beatty, Tilbury Douglas) whereas the sinkhole is on the Yellowham Hill Improvements c. 1991 AMEC (promoted as the first DfT D & B contract)

[Richardf]

This may not be a straightforward or simple repair. The whole area by quirk of geology is very prone to sinkholes (or swallet holes as they are known locally) and there are many throughout the nearby woodlands, some are huge. These of course are out of the way and not a problem but now its occurred on the road it suddenly becomes one (for obvious reasons).

Its perfectly possible this is just the tip of the iceberg and there is now a serious structural issue with the road. The possibility of which was either not considered or ignored when the road was built along the chosen route.

On an historical note, the old route has probably never experienced this problem since its route could well (by chance) avoid the problem geology.

[Conekicker]

Maybe I'm being stupid, but...

The A35 here is a dual carriageway, yes?

So why on earth can't they just put in a 100 yard (or so) contraflow past the scene, with a temporary speed limit if necessary?

I appreciate that the reality would need three weeks advance preparations to install the two miles of SPECS monitored lower limit first...

Speed limit is a minor worry. If there are no hardened crossovers (which there aren't) how are they going to magically appear? TBH your first sentence is probably correct

Crossovers - not installed as part of the original design. However, if crossovers were built after opening, to enable future maintenance schemes, they will most likely still be present as it's pointlessly expensive to dig them out. The only slight problem might be that even if there are two in the area, they're going to be several kilometres apart and could skip junctions that contraflowed traffic might want to use.

On the other hand, if there were two in roughly the right spot, then it would take no more than a single night to get a contraflow installed if you're geared up to do it. Which might be another slight problem.

On the motorway network, HE went through a programme a few years back of installing these things in strategic locations:
https://www.asset-vrs.co.uk/permanent/sologuard/
Whether any were installed on the A roads I can't recall but it's a good idea if you want some network resilience.

In the days when contraflows were our "go to" solution for major maintenance schemes, as a designer I often found there were old crossovers in roughly the right locations for the section we wanted to work on. Sometimes they needed extending by up to 50 metres, less often totally new ones were needed. Occasionally there could be a kilometre or more of extra TM if the crossover was a bit far from the works area - but that extra bit of contraflow length was far quicker and cheaper to provide than building a new crossover. If we were working along a motorway, knowing that the next 3-4km would be worked on next year, we'd make a point of building a crossover as part of the scheme to enable next years work to go ahead that bit easier. Ideally crossovers should exist in pairs at roughly 4km intervals, 150m or so long with a gap of around 250m between each one.

[SteveA30]

Latest news today, a contraflow is being considered now. Looks like they think this is a long term job, the Spring Bank Holiday rush starts a week on Friday.

https://www.bbc.co.uk/news/uk-england-dorset-57140863

[WHBM]

Latest news today, a contraflow is being considered now.

Really ... has it taken HE this long to read the thread here ?

[RichardA35]

Latest news today, a contraflow is being considered now.

Really ... has it taken HE this long to read the thread here ?

Not really - affected parishes have their own specialist who contacted HE, Dorset Council, the local councillor and MP last week to exert pressure with suggested solutions.

[WHBM]

Not really - affected parishes have their own specialist who contacted HE, Dorset Council, the local councillor and MP last week to exert pressure with suggested solutions.

Aha ! You are Richard Drax and I claim my £5.

[Conekicker]

Latest news today, a contraflow is being considered now. Looks like they think this is a long term job, the Spring Bank Holiday rush starts a week on Friday.

https://www.bbc.co.uk/news/uk-england-dorset-57140863

A contraflow on a dual 2? I trust they'll be using 750mm high cylinders to form the buffer zone, otherwise the first low loader to go through will wipe the lot out.

[Bryn666]

Latest news today, a contraflow is being considered now. Looks like they think this is a long term job, the Spring Bank Holiday rush starts a week on Friday.

https://www.bbc.co.uk/news/uk-england-dorset-57140863

A contraflow on a dual 2? I trust they'll be using 750mm high cylinders to form the buffer zone, otherwise the first low loader to go through will wipe the lot out.

Cylinders in a contraflow? I thought the hyper risk-averse clipboards had stopped that practice? Last time I saw one was about 2005, it's always been steel down the middle since... let's not forget the glossy PDF propaganda where HE praised itself to the skies for inventing contraflows for smart motorway works, ignoring the fact contraflows have existed in various forms since at least 1960.

[A9NWIL]

Latest news today, a contraflow is being considered now. Looks like they think this is a long term job, the Spring Bank Holiday rush starts a week on Friday.

https://www.bbc.co.uk/news/uk-england-dorset-57140863

A contraflow on a dual 2? I trust they'll be using 750mm high cylinders to form the buffer zone, otherwise the first low loader to go through will wipe the lot out.

Cylinders in a contraflow? I thought the hyper risk-averse clipboards had stopped that practice? Last time I saw one was about 2005, it's always been steel down the middle since... let's not forget the glossy PDF propaganda where HE praised itself to the skies for inventing contraflows for smart motorway works, ignoring the fact contraflows have existed in various forms since at least 1960.

On a D2 wouldnt there be issues with a solid steel barrier in a contraflow if there is a wide load? Surely it would be something less solid but they just reduce the speed further to say 40mph?

[Conekicker]

Latest news today, a contraflow is being considered now. Looks like they think this is a long term job, the Spring Bank Holiday rush starts a week on Friday.

https://www.bbc.co.uk/news/uk-england-dorset-57140863

A contraflow on a dual 2? I trust they'll be using 750mm high cylinders to form the buffer zone, otherwise the first low loader to go through will wipe the lot out.

Cylinders in a contraflow? I thought the hyper risk-averse clipboards had stopped that practice? Last time I saw one was about 2005, it's always been steel down the middle since... let's not forget the glossy PDF propaganda where HE praised itself to the skies for inventing contraflows for smart motorway works, ignoring the fact contraflows have existed in various forms since at least 1960.

Well you could put a metal barrier down the middle of a 1+1 contraflow, providing you were ready with the requisite recovery vehicles to hoick out the first wide load that got stuck trying to squeeze through, or the congestion every time there was a breakdown or collision.

That's not to say some dumpling might specify a metal barrier for such a road but you'd like to think a grown-up would have words before any was actually placed.

Can't honestly recall the last time I did a contraflow, must be well over 10 years ago now.

[Bryn666]

Yeah, you've got more faith than I have. I feel like Gordon Ramsay asking for lamb sauce most days.

[SteveA30]

An oversize load on the old road, with an escort van just gone past. No need for any infrastructure, GSJ's at both ends. Opposing traffic is literally once every 5-10 minutes and most of that was me. One of the quietest bits of old road anywhere. When will they see sense?

[solocle]

A contraflow on a dual 2? I trust they'll be using 750mm high cylinders to form the buffer zone, otherwise the first low loader to go through will wipe the lot out.

Cylinders in a contraflow? I thought the hyper risk-averse clipboards had stopped that practice? Last time I saw one was about 2005, it's always been steel down the middle since... let's not forget the glossy PDF propaganda where HE praised itself to the skies for inventing contraflows for smart motorway works, ignoring the fact contraflows have existed in various forms since at least 1960.

Well you could put a metal barrier down the middle of a 1+1 contraflow, providing you were ready with the requisite recovery vehicles to hoick out the first wide load that got stuck trying to squeeze through, or the congestion every time there was a breakdown or collision.

That's not to say some dumpling might specify a metal barrier for such a road but you'd like to think a grown-up would have words before any was actually placed.

Can't honestly recall the last time I did a contraflow, must be well over 10 years ago now.

I mean, isn't the simplest solution to run it as a standard S2 through the contraflow?