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N8/N25/N40 - Dunkettle Interchange [under construction]



  • What can the NRA do eh? dependent on the whims of their political masters for any funding, the Dunkettle upgrade will still be a long way down the list of road funding priorities despite it's AADTs and strategic importance. Gotta build all those 'corridors' to nowhere first.
    In fairness the main reason Dunkettle is a long way from starting is because it was a latecomer to the planning process. I remember it only appeared on the NRA's site about 2 years ago. Long time more before it'd be ready for construction - and it's a highly complicated scheme:

    - Grade-separate long distance traffic
    - Must be fully freeflow in all directions
    - Local traffic must be rerouted
    - Entrance to a tunnel to the immediate south, with a steep descent
    - Rail line running through the area
    - Attempts being made to add a P&R to the junction, which would need to be accessible from both the M8 and the N25 - very hard to achieve whilst maintaining full grade separation.

    The scheme must of necessity be very complex and expensive. Let's make sure we get it right.

    It's interesting because there is an identical situation in the north up in Belfast. They spent ages upgrading their Westlink and widening the M2, but only after this was finished did they start planning for an upgrade of the Westlink/M2/M3 huge interchange right in the middle of town. Now Wesley Johnston is saying it'll be 2020 before they get working on it.

  • Add to that Dunkettle house and gardens which are protected and are sitting right on top of it. Also parts of the Lee nearby are SACs.

  • Are there any quick-build public transportation options on the table to relieve some of the pressure on Mahon/Douglas/Blackrock, like turning the Passage West Railway line into a BRT? Doesn't help that they (IIRC) put a sewer under it of course.

    If there was ever a classic case of more road creating more demand, the SRR seems to be it, except it's supposed to be private motorists to blame not the bloody city council!

  • It is proposed to upgrade the interchange to fully free flow in all directions and to include measures to remove locally generated traffic from the interchange.
    Despite the fact there is pretty much no way we'll be seeing this happen in the next few years, it's good to know at least that the NRA are working on a full solution for the interchange and recognise that slapping on a few free-flow slips simply won't be enough.

    I have NO idea how they're going to introduce the (necessary) third level of grade seperation though. The task facing the engineers is uneviable to say the least. I have a feeling it could see the entire interchange demolished and started from scratch.

  • I've been informed that Jacobs were awarded the contract for the Dunkettle EIS over a month ago. Presently they are being briefed on all previously considered upgrade options. A public consultation document will issue in 2011.

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  • I noticed this morning that they have repainted the road marking on the approach and exit of the tunnel northbound.

    The left lane reads N8 Dublin / Cork then the lane separates into N8 Cork & N8 Dublin. This is written about four times before you reach the traffic lights at Dunkettle.


  • They are resurfacing the N25 between the Dunkettle interchange and Little island (probably further on but I don't know as I get off at the Little island exit)

    They have removed the 120km/h speed limit signs and replaced them with 60km/h ones. That seems a bit odd to me. Why can’t they just put up the temporary orange speed signs and cover the existing ones.

    I hope that when the road is repainted it will retain its motorway markings (continuous yellow line) like they did on the newly resurfaced part of the Carrigtwohill to Midleton stretch. I know it’s not motorway but hopefully it will be declared one at some point.

  • That resurfacing urgently was needed. The bit between the merging slip and the running lanes was cracking, and some of the pits it produced were about 20cm deep.

  • Can't find a Dunkettle thread, so I'll put this in here.

    Long story short, the NRA have published the plans for the Dunkettle upgrade. Loads of people think it's a great idea. But there's no money.

    €100m plan to end Cork traffic nightmare
    A 100m transformation of the busiest road junction in Cork will breathe new life into the region and create much-needed jobs, industry leaders said today.

    The traffic-choked Dunkettle Interchange used by 95,000 motorists daily will become a completely free-flow junction, with looping flyovers and slip roads, under plans unveiled by the National Roads Authority (NRA) yesterday.

    The multi-million euro scheme has been compared to the complete revamp of the traffic bottleneck at the Red Cow in Dublin, where a congested roundabout was replaced with slip roads and flyovers to ensure traffic flowed freely.

    Consultants working on behalf of the NRA revealed five different options for Dunkettle yesterday.

    The final project to be chosen by September could include up to 10 bridges, with looping flyovers, new access routes to Little Island and Glounthane and a completely new roundabout adjacent to the existing Dunkettle Interchange. Construction of the project will begin in 2014 if funding is secured.

    This would follow the completion of the flyovers at the Bandon and Sarsfield Road roundabouts.

    The Construction Industry Federation (CIF) has warmly welcomed the plans, saying it will create hundreds of much-needed jobs in the beleaguered construction sector.

    CIF director Joe O’Brien said: “It is vital that the Dunkettle Interchange is upgraded. We’re very anxious to ensure that funding is forthcoming for this project.

    “Apart from the flyovers at the Bandon and Sarsfield Road roundabouts, the NRA has no other major infrastructure planned for the Cork region.

    “The jobs that this project would create are badly needed.”

    Port of Cork chief executive Brendan Dempsey said a free flow Dunkettle Interchange would be welcomed by all businesses in the city and county.

    “Anything that will ease congestion at that interchange is to be warmly welcomed by all,” he said.
    The upgraded Dunkettle could also aid the Port of Cork’s plan to move its operations to Ringaskiddy.

    The Port will apply for planning permission later this year or early 2012 for a scaled down investment on a new lower harbour container facility in Ringaskiddy.

    The Port’s previous application to create the container terminal at Oyster Bank in Ringaskiddy was refused by An Bord Pleanála, which cited a lack of a rail connection and proper road infrastructure.

    Read more:


    Public consultation document out now, but I can't find any drawings of the 5 options jacobs have come up with....

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  • Another, better detailed article.

    THE busiest road junction outside of Dublin is gridlocked, stifling economic development and urgently requires a major overhaul, which could cost up to €100 million.

    The National Roads Authority (NRA) has unveiled five options for the redevelopment of the interchange at the Jack Lynch Tunnel/Dunkettle roundabout, which copes with approximately 95,000 vehicles a day.

    At peak times motorists are snarled in serious gridlock and the NRA is aware that something needs to be done to allow for the development of the Cork region and that speedy access to and from it is a key component for economic recovery.

    The junction is the main artery feeding Cork’s business heartland. The tunnel connects the northern and southern sides of the city and also links with the main Cork-Dublin road (N8) and the Cork-Waterford road (N25).

    In the future it will also have to provide a link to the Atlantic Corridor, connecting Cork with Sligo.

    It is envisaged that another junction will be built at the northern end of the Glanmire bypass, with a connection across the northside of the city to the Cork-Limerick road, feeding into the Atlantic corridor.

    The need for a major crossing of the River Lee was identified as far back as the late 1970s as congestion mounted in Cork city centre.

    It was never envisaged when the four-lane, two bore 1.85km-long tunnel opened on May 31, 1999 that it would carry as many vehicles as it does today.

    Initial predictions stated that the tunnel would cope with up to 30,000 vehicles each weekday.

    Today the tunnel alone carries 60,000 vehicles each day, all of which have to negotiate the signalised roundabout on the northern side of the tunnel, slowing down journey times.

    The same roundabout also has to cope with traffic coming out of the city centre along the Tivoli dual carriageway which is heading north to Dublin.

    At peak times in the morning traffic can tailback more than two kilometres on the northern side of the tunnel and on occasions nearly as far as the Little Island interchange on the eastern side.

    In the evenings in particular, commuters on their way home often join queues on the South Ring Road adjacent to the Rochestown Park Hotel.

    The NRA wants to divert as much unnecessary traffic away from the signalised roundabout on the northern side of the tunnel as it can, so as to speed up access through the tunnel itself.

    For example, traffic heading for Dublin has to do so by accessing the roundabout just metres from the mouth of the tunnel.

    A new dedicated slip road is planned on the western side of the tunnel which would take traffic directly up the Dublin road, instead of it having to first pass through the roundabout.

    By creating further dedicated slip lanes and elevated loops, a lot of traffic will be removed from the roundabout and getting rid of the lights will enhance "freeflow".

    The NRA’s consultants, Dublin-based Jacobs Engineering, are working on computer-generated traffic flow models for each of the five options to see which one works best.

    NRA spokesman Sean O’Neill said the junction represented "a critical piece of infrastructure" not just for Cork but for the whole south-west region.

    "It is equivalent in importance to the M50 corridor, which is now flowing freely because traffic lights have been removed," Mr O’Neill said.

    The options under consideration would cope with traffic increases in the area for the next 30 years. The construction of flyovers, loops etc would have a minimum lifespan of 120 years.

    "The junction is the economic backbone of the Cork region. 90% of freight traffic is carried by HGVs so the upgrading of the junction is important to the economic wellbeing of the region," Mr O’Neill said.

    The NRA has jealously guarded land around the interchange for years, primarily to ensure it has enough space to expand the road network, or as Mr O’Neill puts it "to protect the taxpayers’ investment".

    The roads authority was previously successful with Bord Pleanála in objecting to a number of development plans in the Cork region, primarily because of the inability of the interchange to cope with ever increasing traffic flow.

    It first won a battle with a developer who planned to build 1,200 houses on the grounds of Dunkettle House, which overlooks the tunnel’s northern approaches.

    The NRA said the development, proposed by O’Flynn Construction, would "add to further pressure on the interchange" and would be "premature" until it had upgraded the major road network.

    It also made a successful objection against plans by Iarnród Éireann and Cork County Council to use a greenfield site close to the former Ibis Hotel to create a park and ride commuter railway station.

    The NRA claimed it might require the land earmarked for the station for part of its interchange upgrade.

    The Port of Cork’s plans for a new €120 million cargo terminal at Ringaskiddy were also scuppered because Bord Pleanála decided, in part, that congestion at Jack Lynch Tunnel was so critical that more juggernauts passing through it as a result of that project would grind the underwater crossing to a complete halt.

    The Port authority believes that the deep water quay at Ringaskiddy is the most viable option for its container terminal, although it is looking at the jetty at the former IFI plant at Marino Point, Cobh.

    Mr O’Neill said the NRA wanted to ensure an integrated transport system in the area, and that didn’t mean the park and ride station was off the agenda.

    He stressed that discussions were ongoing between the NRA and Iarnród Éireann to develop a station in the locality.

    If opened it would undoubtedly be the busiest station on the Cork-Midleton commuter line as many people from north and east Cork would be likely to opt to leave their car at the park and ride, thus avoiding lengthy queues along the Tivoli dual carriageway at peak times as well as expensive parking charges in the city.

    "Without question we want to work on integrating all transport. Once our discussions conclude we will see a proper place (for the railway station) identified," Mr O’Neill said.

    Iarnród Éireann owns an extensive freight yard at North Esk, part of which could eventually be chosen as the site for the new station. In all of the NRA options there are proposals to create a dedicated slip road off the M8 heading southbound from the Caherlag area directly down towards North Esk, which would accommodate traffic heading to the park and ride.

    Mr O’Neill declined to comment on whether the junction upgrading would allow for the development of the Port of Cork’s proposed cargo terminal in Ringaskiddy, or the O’Flynn Construction €400 million project at Dunkettle.

    He said he was not aware at this stage if the Government would introduce toll charges in the area to pay for the project.

    "I’m not aware of any tolling right now. That would be a Government policy decision," Mr O’Neill added.

    The question remains in this pot-hole riddled economy, if the Government will release any cash for such an ambitious project, or will motorists foot the bill at toll booths?

    Anone have links to the actual options Jacobs are considering?

  • The drawings are included in this brochure (attached).

  • FatSh!te wrote: »

    another, better detailed article.

    Anone have links to the actual options Jacobs are considering?

    That article is playing down the situation. It says that
    In the evenings in particular, commuters on their way home often join queues on the South Ring Road adjacent to the Rochestown Park Hotel.

    I have seen it back as far as the kinsale road roundabout. Most friday evenings it will be back to the first douglas slip road.

    Tolling it would be the worst idea ever. It will just drive more traffic into town. There are already enough tolls going to Dublin for feck sake we dont need a third one (4th one if you pass through the M50)

  • Orange or red please, they can't seriously think that adding more RABs on the N25 wouldn't cause hassle...

  • Dedicated scheme website here:

  • The Options:






  • Is it me or is the blue one overly complicated?

  • Bit of penis envy going on here......

    "If Dublin can have some crazy junctions, why can't we????"

  • Ok, on a more serious note....

    the red option makes most sence as it allows M8 traffic to flow straight in to the tunnel.

    The purple option does not allow this, but has straight flowing traffic to the N25 waterford road. this makes sence if this is the main direction of traffic.

    The other options are just fillers to show they looked at all options.

    Please please please don't have those crazy tight loops like they have on the M50!!!:(:(:(

  • Bit of penis envy going on here......

    "If Dublin can have some crazy junctions, why can't we????"

    It seems you have the attitude that every piece of infrastructure should be in Dublin and the rest of the country should have horse and carts. This junction carries as much traffic as the red cow on some days.

    You literally have not got one clue as to what happens outside of your county.

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  • Bit of penis envy going on here......

    "If Dublin can have some crazy junctions, why can't we????"

    Having to travel through this joke of infrastructure twice daily on my commute to and from work, can I personally say to you, that you sir are an idiot.


  • Why can't they design a normal looking 4/5 level stack or a clover leaf?

  • irishdub14 wrote: »
    Why can't they design a normal looking 4/5 level stack or a clover leaf?

    Heights and Little Island's access. Remember we're dealing with a tunnel portal below ground level at one end.

  • the red option makes most sence as it allows M8 traffic to flow straight in to the tunnel.

    Southbound only? Am I missing something or is there no corresponding route northbound?

    (other than turning at the roundabout to the west of the main junction)

  • There is a north-bound free flow in the purple option.

    As i recall, the land for the junction was reclaimed from the estuary, so there should be enough room for the design of proper loop/slips where a decent speed can be done.

    Ideally all directions should be freeflow IMO, a simple clover leaf rather than overcomplicating the junction. The levels issue shouldn't be too hard to sort out.

  • Just a quick question.

    All of the options involve no traffic lights and no stopping, but some do involve some twisty bits, even when you are continuining in a East - West or North - South direction ?

  • Just a quick question.

    All of the options involve no traffic lights and no stopping, but some do involve some twisty bits, even when you are continuining in a East - West or North - South direction ?


  • Hogzy wrote: »

    And nothing.

    It was just a bloody question. The pictures on page 2 weren't working when I looked last time.

  • Red all the way, though I still think my arrangement was better.

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  • And nothing.

    It was just a bloody question. The pictures on page 2 weren't working when I looked last time.

    Whats the question though?
    Yes they have twisty bits :confused: