N8/N25/N40 - Dunkettle Interchange [open to traffic]

dontwatchtrailers

https://www.boards.ie/discussion/comment/121757137#Comment_121757137

This 100%. Such a change could be done over night and I can't imagine it would do anything other than cause less dangerous merges. Surely the people who designed these roads are aware they're not being used properly (and crashes occur as a result) and as such something should be done about it.

hans aus dtschl

https://www.boards.ie/discussion/comment/121757597#Comment_121757597

The roads in question were designed a very long time ago when traffic was nowhere near current levels and nobody imagined that the city would expand the way it did. Current designers are now firefighting a distributor/bypass mess. The primary way these roads are being used incorrectly is by thousands of short-distance commuters, and "N40 upgrades" will struggle to deal with that.

DylanQuestion

https://www.boards.ie/discussion/comment/121757807#Comment_121757807

Especially when Bus Connects is advising those outside the N40 in the City South East to stop driving on the R610 to the City Centre and instead use the J7 and J9 on ramps to get to the N40 and N27!

rameire

New Link just open

serfboard

https://www.boards.ie/discussion/comment/121757807#Comment_121757807

According to TII "Traffic volumes through the interchange are at an all-time high approaching 120,000 vehicles on the busier days of the week". Holy God.

Padraig Mor

https://www.boards.ie/discussion/comment/121758326#Comment_121758326

I see from their PR that TII are now in the misinformation business, claiming that "journey times during peak hours have been reduced by almost 50% on average as a result of the upgrade project". I'd be very interested in which 'average' they are using for this calculation - mean/median/mode - and how it was calculated as I'd be very hesitant to believe that everyone using the interchange is experiencing an average 50% reduction. In particular they claim "journey time savings of almost 60% are being achieved on the N40 to N25 route during peak hours, whilst time savings of over 50% are being achieved on routes accessed via the M8 Southbound" - scrupulously avoiding mention of journey times from the N25 eastbound which carries far more traffic than the M8 southbound and which have seen little improvement, and in fact possible worsening! Also, what exactly does "journey time savings of almost 60% are being achieved on the N40 to N25 route during peak hours" mean? I suspect it's measured from after the Mahon junction and through the tunnel which has undoubtedly improved - but ignoring the mile long tailback before the Mahon junction doesn't reflect the real life journeys of people using the tunnel.

KrisW1001

They have data on over 100,000 movements a day. You have personal anecdotes of one driver. I'll trust them.

I used to work with traffic data, and the one thing you see straight away is that it's very random: you can be "delayed" while someone just three or four minutes behind you will sail through. The only way to get sense from it is to look at thousands of journeys at a time.

My own anecdotes, just as worthless as yours, are that N40/N25 is far faster both ways than it was before. My previous experience was of tailbacks before Mahon, then stop-go through the tunnel lights. Now it's a steady if slow progress at busy times.

Coming the other way, there's just no comparison to before.

Chris_5339762

https://www.boards.ie/discussion/comment/121757137#Comment_121757137

... its also on a bend. And before it is another bend. Sightlines aren't great, especially at night. And because that part of the SRR isn't lit.

They should delay the merge until it straightens out before the actual Douglas Viaduct. Would at least force people to merge on a straight bit.

Hibernicis

Dronehawk posted a video showing his first drive over Link C today, plus two others, a retrospective on the construction of the Rail overpass and a Link C taster posted at the weekend

• Dunkettle's Finished - First drive on Link C - https://www.youtube.com/watch?v=YnVfnqwIRsM
• Railway Overpass Rebuild - https://www.youtube.com/watch?v=RpGqd1l6M98
• Final Dunkettle Link opening this weekend - https://www.youtube.com/watch?v=XMF9cUqowXo

Once again, I'd like to salute Dronehawk for bringing this project alive over the last few years, and hope that they continue the amazing work with coverage of the M21, M28, M20 (hopefully), the Killaloe Bypass, the Foynes freight line reopening, Midelton to Glounthane double tracking, other CART work, the Midleton to Youghal Greenway and anything else that comes along.

For anyone that would like to acknowledge the time and effort that Dronehawk has put into documenting this and other projects, they have posted a "buy me a coffee" link on a number of their videos and now might be a good time to show appreciation.

Hibernicis

TII have also published an overview of the project, including a lot of stats - https://www.youtube.com/watch?v=-tl3Uh7scLA

confidentjosh

https://youtu.be/zASDfuTa_sk

DENtv drive through new link

Gunner3629

The greatest benefit appears to be from the M8 Southbound.

For N25 Westbound, I suspect the benefit is less so, particularly at peak times. That is my own observation and I have no stats to back that up.

cork_south

N25 Westbound, from my commuting experience, is very bad at peak times.

Unfortunately at peak times heading to Dunkettle roundabout and doing a U turn is probably the way to go if you want to get thru the tunnel, especially with Dublin bound traffic no longer hitting that roundabout since the final links opened.

AugustusMinimus

Has the opening of Link C had a demonstrable effect on traffic levels hitting the Dunkettle roundabout from the east?

Looking at cameras, there are very few vehicles on the N25 east to M8 north movement. I’ve questioned this movement in the past. To me, it’s potentially the least used of the 12 major movements. I can’t see how it is more trafficked than M8 south to City for instance.

DylanQuestion

Crash at J17 on the M8. Based on the digital signs, you are to get off there to go into Watergrasshill, and I assume back on at Rathcormac

Fabio

https://www.boards.ie/discussion/comment/121761921#Comment_121761921

For some reason (to protect the toll income I imagine) you actually can't enter the M8 northbound at Rathcormac. You can only enter it southbound. So for this diversion people will have to go through Rathcormac and either pay a toll at Fermoy or go through Fermoy town and get on toll-less at the north side of the town.

janjan182

Hear hear!

Chris_5339762

Must have been a very bad crash to have closed the M8 from about 4pm through to 10pm and counting. The usual Bloomfield/N28 shunts are cleared within an hour or so.

swoofer

What is the signposting like? Coming from Clare to get to MATER in near future.

DylanQuestion

I emailed the road construction email listed on the previous page about how inaccurate and confusing some of the signage is at the scheme and this was their response:

”Thank you for your email below and thank you for taking the trouble to contact us and bringing this item to our attention.

 As you may be aware, a detailed directional signage approval process is in place for National Roads and this process was followed on the Dunkettle Interchange Upgrade Scheme. However, your comments are noted and we have brought these comments to the attention of Transport Infrastructure Ireland who operate the approvals system.

 We will be in contact with you again on receipt of their follow up comments.”

Brussels Sprout

https://www.boards.ie/discussion/comment/121766989#Comment_121766989

If you're coming via the Limerick road then you can avoid the Dunkettle altogether by just following that road into the city centre, crossing the Christy Ring bridge, driving up the quays and then getting onto the South link road from there which will bring you to Mahon. Any sat nav will be able to sort you out there.

Hibernicis

https://www.boards.ie/discussion/comment/121766989#Comment_121766989

Alternatively, if you want to avoid crossing the city, you could join the M8 at Mitchelstown or Fermoy. From there you go straight through the Dunkettle Interchange, take the first left on the N40 westbound, take a right at the lights and then right at the third set of lights and you're there. Downside of this is getting from Clare/limerick to the M8, upside is the almost certainty of no delays at the end of your journey.

niloc1951

https://www.boards.ie/discussion/comment/121766989#Comment_121766989

The least stressful is the N24 Waterford Road from Limerick, after about 7km turn right onto the R513 which will take you the whole way to Mitchelstown where you can pick up the M8, and then it's a straight run down to Mahon.

That way you avoid the sh1te N20 and having to negotiate the Cork city traffic and one-way system.

Fabio

Has traffic settled down now that all links have been open for a while???

cork_south

https://www.boards.ie/discussion/comment/121796848#Comment_121796848

The junction is a huge improvement outside of peak times.

In the evenings traffic is still backed up to Rochestown Park for tunnel northbound traffic, but does move well.

Coming from the East at peak times in the morning is very bad however with the 4 lanes merging to 1 before entering the tunnel.

With the merging issues at Bloomfield it renders the free flow ineffective at the interchange in the mornings with traffic backing up into the tunnel, up the M8 and down the N25.

Fabio

https://www.boards.ie/discussion/comment/121796882#Comment_121796882

Sounds like the east will be an issue for a long time then.

I wonder when they'll be fully finished with the "tidy up" works?

I've used M8 South - N40 West and M8 South - N8 City a lot and they've been really good, especially outside of the usual peak times.

niloc1951

I drove eastbound on the N40 towards the tunnel at rush hour this evening. From Broomfield to the tunnel it was very slow and stopped at times.

I think the queueing is the result of a lot of drivers not understanding that the speed limit is back up to the pre works level and are still slowing to 60kmh like it was during construction. If drivers moved a little quicker (within the speed limits) it would help to reduce the development of the queue.

_Kaiser_

https://www.boards.ie/discussion/comment/121804882#Comment_121804882

Oh have they finally removed the 60 km/h limit from just beyond Mahon to the tunnel? (I haven't been down in a few weeks).

What's it now then? Is it still 60 when you come out the other side to the M8 North? Can't see that legitimately being much more from the way it's been built. Likewise on the other side coming to the tunnel.

AugustusMinimus

Huge amount of trees being planted around and in the interchange. Nice to see more than just grass.

_Kaiser_

https://www.boards.ie/discussion/comment/121806961#Comment_121806961

As long as thy don't interfere with visibility/sight-lines. There's a lot of "nice looking" roundabouts that you can't see anything beyond on approach - part of the issue being massive (from the perspective of the driver's seat in a saloon) directional arrows for people who don't know what side of the road we drive on here...

DylanQuestion

https://www.boards.ie/discussion/comment/121806961#Comment_121806961

Are they 'proper' trees or small sapling looking things?

BagofWeed

https://www.boards.ie/discussion/comment/121708092#Comment_121708092

Sorry for the late reply. But I just can't see either road being build or in the case of a NDR, being completely built as it passes areas where nimbyism will be strong. This is a copy/paste of a previous post I wrote regarding the NDR.

'I'm all for the distributor and the NNR but both should have been done before the increase in nimbyism and anti car rhetoric. The distributor will have several flash points for nimbyism: the veer off from the existing nrr over to the Banduff and Rathcooney Roads/ Banduff House expect opposition from residents, westbound from the Kinvara Link Road goes through fields near Murphy's Rock and already this year there has been calls to put a development ban there Locals calling on EU to designate Murphy's Rock an Special Area of Conservation (echolive.ie), Sweeneys Hill the people of Rathpeacon won't be happy that both NRR and the distributor will be cutting through their community in the case of the NRR it will be below An Bothar Dearg, the section from the Blarney Rd, Hollyhill towards and over the Lee also will get some environmentalists upset too especially as the NRR would also require a bridge further west along the Lee.'

If sections of it are built they will be clogged up immediately with traffic as Cork City Council will put traffic lights on every junction.

cantalach

https://www.boards.ie/discussion/comment/121811187#Comment_121811187

They’re saplings, which will grow up into proper trees. The quality of planting along the motorway network in this country has been very good in my opinion. They plant a mixture of species that grow quickly and those that grow more slowly. Within 10 years it should be very lush all around the interchange, as depicted in the CGI renders from 5-6 years ago.

DylanQuestion

Great, thanks! Hopefully the saplings survive. It looked great in the renders, but is very sterile quite now

DylanQuestion

I can't believe they still haven't upgraded the signage at Dunkettle Roundabout. They're still using South Ring instead of Westbound, and it directs you to the N25. That's fine for all of us on here but if you're not familiar with the area or the numbering system for roads, it's probably confusing. For example, if you see a sign saying South Ring N25, and then later down the road signs for N25 and N40 Westbound, you'll probably assume that the N25 is for the link, not the N40

Hibernicis

I think the response you received a couple of weeks ago indicated the lack of urgency on this. Which is most disappointing. The signage really does need to be looked at and the misleading and inconsistent elements cleared up.

_Kaiser_

https://www.boards.ie/discussion/comment/121805362#Comment_121805362

Anyone? I'll be down next weekend but curious as to what the "final" speeds are now. As above I can't see 80 km/h exiting the tunnel to M8 working well given the angle, and equally if it suddenly drops from 80-60 at that point I can see issues too!

Have they gotten rid of the (wayy too far out) 60 approaching from the M8, or is it now 60 at the new interchange, 80 through the tunnel, 100 beyond which to be fair would make the most sense IMO.

DylanQuestion

I drove it today and from Mahon to just before the tunnel was 100km/h. Then it changed to 80km/h in the tunnel. Although, I swear I saw a random "50km/h in 500m" sign but the actual 50km/h never appeared. Also, going onto the N8 on ramp from the M8 (at the fork between City Centre and Waterford), I could see the N25 was 80km/h. I'm not sure where it goes to 100km/h

Hibernicis

https://www.boards.ie/discussion/comment/121819839#Comment_121819839

I drove it last evening but hadn’t seen your question and was more focussed on the gantry signage when I came out of the tunnel (to see if it had been altered/improved - it hasn’t). So I wasn’t particularly tuned into the speed limit changes, but I think the following is how it is:

1. 100kmh under the Mahon Junction (N40 J10) approaching the tunnel
2. Drops to 80Kmh on the straight section after the above junction, same place as pre-construction Remains at 80Kmh through tunnel
3. Unsure if it drops at the exit from the tunnel
4. I am almost (95%) certain that it does drop to 60Kmh shortly after the demerge exit to Link D (where Link D passes under Link C and the N25 Mainline)
5. Speed reverts to 100Kmh shortly after the point where Link D, Link C and Link U merge at the start of the M8N

Logically there should be a step up to 80Kmh between points 4 and 5 above but I didn’t notice it if there is

The links listed above are as follows:

• Link C - N25W to M8N
• Link D - N40E to M8N
• Link U - N25E to M8N

Feel free to correct the above after you drive through next week if nobody has rubbished my post in the meantime.

freshpopcorn

Back in 1996!

cork_south

https://www.boards.ie/discussion/comment/121823521#Comment_121823521

All that space to have filter lanes on each junction of the roundabout from day 1 and they still decided to go with the cheapest option available with a bog standard roundabout.

hans aus dtschl

https://www.boards.ie/discussion/comment/121823609#Comment_121823609

Wasn't it the most expensive project in the state at that point though? I heard that they agonised over it, and cut the middle tunnel bore to nothing because they were so worried about the cost.

Cookiemunster

https://www.boards.ie/discussion/comment/121824215#Comment_121824215

Middle bore? It's an immersed box tunnel. The the 4 lane concrete sections would have been poured on land, floated out onto the Lee and then sunk into their final position in a pre dug trench. There was no boring.

I have to say the route in from the N25 to the N40 / Jack Lynch Tunnel where you have to do that merge with the traffic coming in from the M8 is absolutely horrible. I was coming in on it late a few evenings ago and someone came down at way faster than the speed and started flashing and beeping at people who were mid-merge.

I'd hate to have to see traffic lights going back on, but if they don't do something about the speed on that junction e.g. with serious permanent speed cameras, they're going to start seeing accidents.

If they put up some permanent speed cameras and ANPR on that junction it would run completely smoothly. It just needs a ton of fines issued. There's no need to break the speed limits on it. Some of them are a bit conservative, but it's literally going to slow everyone down if there's muppets cutting people off and preventing merges.

https://www.boards.ie/discussion/comment/121824275#Comment_121824275

From what I have read about the project, they created a dry dock which I think was where the GAA pitches are, just beyond Blackrock Castle. The sections were cast, and the ends were sealed / plugged. Then the dry dock was flooded, and they were floated into position. They sink the sections in to a pre-dredged trench, but I don't think they flood the interior with water at any stage. There may be some buoyancy chambers that were flooded with water that form part of the structure and the rest would have involved heavy ballast. They're just placed into line, sealed and grouted up etc, and then there's very heavy ballast placed across the top and the river bed is reinstated.

It's basically a massive dredging exercise.

The dry dock area was then reclaimed as GAA pitches and the walkway.

_Kaiser_

https://www.boards.ie/discussion/comment/121824281#Comment_121824281

I could be wrong but traffic merging should end up in the left lane of the tunnel and not impact on traffic inbound from the M8 unless they're trying to cut across into that right lane - in which case said flashing and beeping may have been entirely justified as many people do so regardless and (especially in Cork in my experience) without any use of indicators.

https://www.boards.ie/discussion/comment/121824310#Comment_121824310

There's definitely a merge involved on one of those connections.

It's not on google maps yet, so I can't show it, but there's a left lane that ends and shoves traffic into a merge.

The merge from Dunkettle onto the M8 is also very short.

I think the whole thing needs speed cameras that limit it to about 50-60km/h just for the interchange itself, not the straight parts.

If everything's moving at a gentler speed, it will all flow nicely.

_Kaiser_

https://www.boards.ie/discussion/comment/121824317#Comment_121824317

Fair enough.. Bad design then caused by a compromised overall solution but compounded by unfamiliarity/inattention/impatience/ignorance.

hans aus dtschl

https://www.boards.ie/discussion/comment/121824275#Comment_121824275

Look up the definition of the word bore.

And the rest of your post is also inaccurate. It is not a 4-lane concrete section but a 2+1+2 lane concrete section.

I was told that the middle bore was reduced in size from the original design, but I have no evidence that they had ever properly considered a reasonable size for that middle bore. Also, I don't know what they were doing with the access road to the South of the tunnel management building, but would love to know.

https://www.boards.ie/discussion/comment/121824336#Comment_121824336

You could deal with the impatience easily enough though with a few cameras and automatic enforcement. Overall the benefits to traffic flow would be quite significant and it would avoid a lot of stupid nonsense with potential minor bumps clogging it up.