A1(M) Darlington Crash Barriers

[JammyDodge]

Having recently driven through during the day I have noticed that since the crash barriers have been replaced on this stretch that there is now a black and white checkered pattern on the inside of the 2 curves where it crosses the Tees

Have to say I found it quite distracting with this flashing past out the corner of my eye. The 1st time it took me about 20s to figure out what the hell it was, distracting me from the road.

I can understand the reason this might have been done, but at the same time, why?

[KeithW]

see
https://www.newtonnews.co.uk/bridge-bar ... arlington/

[SteelCamel]

If you're talking about the black and white stripes here it's not new. At one time it was quite common to paint barriers (and kerbs) like this for better visibility, but this hasn't been the case for many years. In fact you can see that repairs have just used plain unpainted metal, leaving it a bit of a patchwork.
Have they replaced the barriers with new painted ones? If so I wonder why - it's not a current standard, and would be a lot of work to paint them. The Google view from May 2023 shows new unpainted barriers, so they must have been painted afterwards.

[JammyDodge]

If you're talking about the black and white stripes here it's not new. At one time it was quite common to paint barriers (and kerbs) like this for better visibility, but this hasn't been the case for many years. In fact you can see that repairs have just used plain unpainted metal, leaving it a bit of a patchwork.
Have they replaced the barriers with new painted ones? If so I wonder why - it's not a current standard, and would be a lot of work to paint them. The Google view from May 2023 shows new unpainted barriers, so they must have been painted afterwards.

I can now see that they have been there before. Probably couldn't notice because it was so faded

[Chris Bertram]

If you're talking about the black and white stripes here it's not new. At one time it was quite common to paint barriers (and kerbs) like this for better visibility, but this hasn't been the case for many years. In fact you can see that repairs have just used plain unpainted metal, leaving it a bit of a patchwork.
Have they replaced the barriers with new painted ones? If so I wonder why - it's not a current standard, and would be a lot of work to paint them. The Google view from May 2023 shows new unpainted barriers, so they must have been painted afterwards.

In Norn Iron, kerbs are sometimes painted red white and blue, but possibly not for the same reason.

[MotorwayGuy]

The slip roads on the M2 at junction 5 used to have them, but they have recently been replaced. Junction 6 still has some intact but it is hardly visible now. I believe the original slip roads at junction 2 that were similar to those at 5 and 6 also had them.

[orudge]

The A90 has the same black and white painted central barriers at the sharpish bend just south of the River South Esk bridge at Finavon.

[nowster]

In Norn Iron, kerbs are sometimes painted red white and blue, but possibly not for the same reason.

Except for a very very few places where they're painted Green/White/Orange. (I only saw this in Toome Bridge in the early 1990s... but there's a heck of a story to that day.)

[Dougman]

Good old Barriermatic used to be all the rage back in the day.

[AndyB]

In Norn Iron, kerbs are sometimes painted red white and blue, but possibly not for the same reason.

Except for a very very few places where they're painted Green/White/Orange. (I only saw this in Toome Bridge in the early 1990s... but there's a heck of a story to that day.)

There are also black and white kerbs on road race circuits in NI - rather faded here on one of the corners of the former Carrowdore 100 circuit, but still present at corners on the NW200 and Armoy Road Race circuit.

[Dougman]

In Norn Iron, kerbs are sometimes painted red white and blue, but possibly not for the same reason.

Except for a very very few places where they're painted Green/White/Orange. (I only saw this in Toome Bridge in the early 1990s... but there's a heck of a story to that day.)

There are also black and white kerbs on road race circuits in NI - rather faded here on one of the corners of the former Carrowdore 100 circuit, but still present at corners on the NW200 and Armoy Road Race circuit.

There's also some around here albeit a bit faded.

[jabbaboy]

Have they replaced the barriers with new painted ones? If so I wonder why - it's not a current standard, and would be a lot of work to paint them. The Google view from May 2023 shows new unpainted barriers, so they must have been painted afterwards.

Yeah they have, never mind why they're black and white. I'm more baffled at why there's a metal barrier at all. Last time I checked, all barriers were meant to be getting replaced by concrete barriers on Motorways, this is arguably a point where it actually be useful aswell considering there's bends.

[Conekicker]

Have they replaced the barriers with new painted ones? If so I wonder why - it's not a current standard, and would be a lot of work to paint them. The Google view from May 2023 shows new unpainted barriers, so they must have been painted afterwards.

Yeah they have, never mind why they're black and white. I'm more baffled at why there's a metal barrier at all. Last time I checked, all barriers were meant to be getting replaced by concrete barriers on Motorways, this is arguably a point where it actually be useful aswell considering there's bends.

DMRB CD 377 is the specification for vehicle restraint systems. It has this to say about central reserve VRS:

E/1.6 On motorways with a two-way AADT greater or equal to 25,000 vehicles/day where a VRS greater than 500m in length is required in accordance with this document, and the distance Psb to Psb is 10 m or less, the safety barrier shall be rigid, have a serviceable life of not less than 50 years, and be designed such that after testing in accordance with BS EN 1317-1 [Ref 8.N] and BS EN 1317-2 [Ref 7.N], it does not require realignment, replacement or repair.

Metal barriers have a life of around 15 years or so and could thus never meet the requirements of the CD's 50 year life and also never meet the realignment, replacement or repair requirements if struck.

I'm not certain but I think the AADT on the A1(M) is under 25,000 vehicles/day, so in compliance with DMRB a rigid (AKA concrete) barrier wouldn't be called for. However, given the life of metal and concrete barriers and with traffic growth in mind, it might be more cost effective to install the concrete on roads with AADT approaching 25k?

The figure of 25k AADT was arrived at as the change point for the barrier life by whole life cost, whenever it was that concrete barrier was first introduced sometime in the 90s or 00s? 3 metal barrier installs and replacements as opposed to 1 concrete barrier install. It would be interesting to crunch the numbers for the costs these days, given the not insubstantial increase in scheme costs this last few years. Perhaps such an exercise would alter the AADT figure. I've noticed a few schemes are now installing precast concrete sections, rather than the usual cast insitu, presumably this is cheaper and thus quicker to install.

Repairing a strike to a central reserve metal barrier is usually an overnight job and is neither cheap nor safe, especially when compared to never (OK hardly ever) having to do the same to a concrete barrier. There have been a few instances of concrete barrier being damaged when they've been struck sufficiently hard enough, but nothing compared to the number of metal barrier repairs that are carried out.

https://www.standardsforhighways.co.uk/ ... nline=true

[wrinkly]

Just north of Darlington, the central wire barrier was replaced by concrete from the north end of J59 to the River Skerne, about halfway to J60, in about 2018.

[KeithW]

Last AADT for the A66(M) was around 15k, at the end of the day its just a long slip road. Looking at the barrier I would suggest its been there a long time. I have never seen any replacement work happening. On the A1(M) near Wetherby about 10 years ago I saw what was potentially a very nasty incident as there was a Range Rover with the front end on the barrier. Two years ago there was a nasty incident on the A1(M) near Durham.
https://www.bbc.co.uk/news/uk-england-tyne-60470301

[jabbaboy]

DMRB CD 377 is the specification for vehicle restraint systems. It has this to say about central reserve VRS:

E/1.6 On motorways with a two-way AADT greater or equal to 25,000 vehicles/day where a VRS greater than 500m in length is required in accordance with this document, and the distance Psb to Psb is 10 m or less, the safety barrier shall be rigid, have a serviceable life of not less than 50 years, and be designed such that after testing in accordance with BS EN 1317-1 [Ref 8.N] and BS EN 1317-2 [Ref 7.N], it does not require realignment, replacement or repair.

Metal barriers have a life of around 15 years or so and could thus never meet the requirements of the CD's 50 year life and also never meet the realignment, replacement or repair requirements if struck.

I'm not certain but I think the AADT on the A1(M) is under 25,000 vehicles/day, so in compliance with DMRB a rigid (AKA concrete) barrier wouldn't be called for. However, given the life of metal and concrete barriers and with traffic growth in mind, it might be more cost effective to install the concrete on roads with AADT approaching 25k?

The figure of 25k AADT was arrived at as the change point for the barrier life by whole life cost, whenever it was that concrete barrier was first introduced sometime in the 90s or 00s? 3 metal barrier installs and replacements as opposed to 1 concrete barrier install. It would be interesting to crunch the numbers for the costs these days, given the not insubstantial increase in scheme costs this last few years. Perhaps such an exercise would alter the AADT figure. I've noticed a few schemes are now installing precast concrete sections, rather than the usual cast insitu, presumably this is cheaper and thus quicker to install.

Repairing a strike to a central reserve metal barrier is usually an overnight job and is neither cheap nor safe, especially when compared to never (OK hardly ever) having to do the same to a concrete barrier. There have been a few instances of concrete barrier being damaged when they've been struck sufficiently hard enough, but nothing compared to the number of metal barrier repairs that are carried out.

https://www.standardsforhighways.co.uk/ ... nline=true

Sorry been busy hence the slow reply. Just checked the AADT figures for the schemes (there's 2 with one further North) and the further North scheme has an AADT of 65k so is well above the 25k so not sure why they've been done with metal barriers to be honest as it seems to fail all the criteria you've listed there. The section further North is the part where the horror crash was a few year ago aswell (as mentioned above) and is the continuation of the concrete barrier installed as mentioned by wrinkly.

Who knows, my guess is no doubt short term £££ savings though. Agreed though that it would just make sense to do most roads now, including A roads, since the A19 has been getting new metal barriers aswell on sections which are well well above 25k aswell, just seems pointless. Short term gains for long term costs.

[Conekicker]

DMRB CD 377 is the specification for vehicle restraint systems. It has this to say about central reserve VRS:

E/1.6 On motorways with a two-way AADT greater or equal to 25,000 vehicles/day where a VRS greater than 500m in length is required in accordance with this document, and the distance Psb to Psb is 10 m or less, the safety barrier shall be rigid, have a serviceable life of not less than 50 years, and be designed such that after testing in accordance with BS EN 1317-1 [Ref 8.N] and BS EN 1317-2 [Ref 7.N], it does not require realignment, replacement or repair.

Metal barriers have a life of around 15 years or so and could thus never meet the requirements of the CD's 50 year life and also never meet the realignment, replacement or repair requirements if struck.

I'm not certain but I think the AADT on the A1(M) is under 25,000 vehicles/day, so in compliance with DMRB a rigid (AKA concrete) barrier wouldn't be called for. However, given the life of metal and concrete barriers and with traffic growth in mind, it might be more cost effective to install the concrete on roads with AADT approaching 25k?

The figure of 25k AADT was arrived at as the change point for the barrier life by whole life cost, whenever it was that concrete barrier was first introduced sometime in the 90s or 00s? 3 metal barrier installs and replacements as opposed to 1 concrete barrier install. It would be interesting to crunch the numbers for the costs these days, given the not insubstantial increase in scheme costs this last few years. Perhaps such an exercise would alter the AADT figure. I've noticed a few schemes are now installing precast concrete sections, rather than the usual cast insitu, presumably this is cheaper and thus quicker to install.

Repairing a strike to a central reserve metal barrier is usually an overnight job and is neither cheap nor safe, especially when compared to never (OK hardly ever) having to do the same to a concrete barrier. There have been a few instances of concrete barrier being damaged when they've been struck sufficiently hard enough, but nothing compared to the number of metal barrier repairs that are carried out.

https://www.standardsforhighways.co.uk/ ... nline=true

Sorry been busy hence the slow reply. Just checked the AADT figures for the schemes (there's 2 with one further North) and the further North scheme has an AADT of 65k so is well above the 25k so not sure why they've been done with metal barriers to be honest as it seems to fail all the criteria you've listed there. The section further North is the part where the horror crash was a few year ago aswell (as mentioned above) and is the continuation of the concrete barrier installed as mentioned by wrinkly.

Who knows, my guess is no doubt short term £££ savings though. Agreed though that it would just make sense to do most roads now, including A roads, since the A19 has been getting new metal barriers aswell on sections which are well well above 25k aswell, just seems pointless. Short term gains for long term costs.

In that case it will be Area 14 doing what they like (again) then. They have some very strange ideas in that neck of the woods.