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

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

Ultimately, you'd be far better off at this stage trying to reduce the traffic volumes on the N40 by spending money on something like a tramway to Carrigaline and through some aspect of Douglas. It may not be entirely justifiable at the current populations, but given the way things are developing, it won't be long until it is.

The tunnel's not going to go beyond 2 lanes each way and widening the N40 isn't really feasible either.

Given the city's population there's far too many cars using that route, with just really indicates a total lack of alternatives at present.

The transit planners also need to look at where people commute to and from. It's not just the city centre. There probably needs to be be a transit interchange on Little Island for example. That should be a major hub on the bus network but isn't.

Same applies to a few other places like that which are huge centres of employment with quite weak public transport or notions that people are going radially all the time, which clearly isn't the case. There's a lot of traffic going orbitally around from residential areas to industrial estates and business parks, basically following the major road routes. Mahon / Little Island / Ballincollig / Carrigaline which could definitely make use of busses to reduce volumes. All of those should have solid bus services.

hans aus dtschl

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

No unfortunately there's a merge alright, and I've seen similar impatient behaviour from people on the M8 tailgating the cars ahead of them etc, and refusing to allow a merge from the N25. As the previous poster said there might need to be some enforcement here unfortunately.

https://www.boards.ie/discussion/comment/121824377#Comment_121824377

I don't know what the fear of using a few speed cameras is though. They're completely reasonable to use in a situation like that and it's not a major imposition. Traffic lights or anything to block the junction would effectively render the whole rationale behind the project pointless.

It's the same on the M50. There are certain drivers are just making it worse by driving too aggressively. All this variable speed limit stuff is fine and well, but it's pointless without enforcement.

Couple it with good signage about avoid stopping, drive smoothly, merge like a zip and everyone gets through faster! Impatience slows everyone down!

Cookiemunster

https://www.boards.ie/discussion/comment/121824338#Comment_121824338

And where, pray tell, is this middle lane?

Whats in the middle is a pedestrian escape route. Not another traffic lane. It was built exactly as it was designed.

DylanQuestion

https://www.boards.ie/discussion/comment/121824373#Comment_121824373

I definitely think there needs to be more connections between Carrigaline and other parts of the city via bus. Right now the only buses are the 220/220x and 225, connecting the town to Ringaskiddy, Cork Airport, Douglas, City Centre, UCC, Model Farm Road, Ballincollig. There is no direct northside connection, no connection to Little Island, and the only connection to Mahon is by transfering to the 219 in Douglas. Douglas is essentially an interchange for Carrigaline. Bus Connects will fix this a bit by adding a direct northside connection (Apple) and interchanges in the City Centre to rest of the city. I still think that Carrigaline could support a direct route between Mahon via the N28 (Well Road is going to struggle to deal with multiple bus routes given it can barely handle the 219) and Little Island, though

niloc1951

https://www.boards.ie/discussion/comment/121824377#Comment_121824377

If we're talking about where the N25>N40 and M8>N40 come together before the northern portal of the tunnel, there is no merging provided for there.

Each lane is separated by a continuous white line the whole way through to the southern portal of the tunnel with 'stay in lane' painted on the road. Any lane changing should only take place after exiting the southern portal of the tunnel where there is over a km for drivers to get sorted before the Mahon exit (Jct 10) is reached.

cork_south

https://www.boards.ie/discussion/comment/121825747#Comment_121825747

I'd imagine people are referring to the merge onto the M8S via the loop from the Dunkettle roundabout direction.

Leatra

https://www.boards.ie/discussion/comment/121825756#Comment_121825756

I'm not blaming anyone in this thread, but the project team (and possibly others) have been woefully inconsistent in referring to that stretch of road. It's the N8, but it all gets wrongly lumped in as N25 sometimes.

AugustusMinimus

Actually, are all of the individual slip roads allocated a national route number?

hans aus dtschl

https://www.boards.ie/discussion/comment/121824457#Comment_121824457

As I said I don't have any evidence but was told was that the central bore was (at one point) considered as an actual pedestrian bore. How early this was in design I don't know, and have only been told this by someone working on it, and I haven't got documents from that early in the project. The few documents I have are all as built.

Edit: and I am in agreement that it was built as designed, that wasn't the point of discussion at all, we were saying that the design was whittled down to the minimum because the project was considered so big by the government at the time. People were looking at the original "simple roundabout" design and marvelling at how basic it was.

Edit: doing a bit of googling here and am surprised at the details I'm uncovering. Apparently the largest project by a local authority in the history of the state, and there was heavy pushback against it particularly on costs grounds. It looks like they really agonised over the design, bumping it from a 2-lane tunnel to a 4-lane one.

hans aus dtschl

https://www.boards.ie/discussion/comment/121825747#Comment_121825747

Sorry, we're not talking about the same thing here, it's the Tivoli to Mahon route we're discussing, if you can visualise that.

Hibernicis

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

You appear to take issue with the use of the word bore. I’ll just leave this here; you might find it educational:

General Tunnel Information

The Tunnel is 620 metres long

There are six emergency exits in each traffic bore for pedestrians that lead into the central bore (pedestrian exit), the exit doors are at each end of the central bore

There are twelve emergency panels in each traffic bore that have hose reels and fire extinguishers

There are six emergency exits in each traffic bore for pedestrians that lead into the central bore (pedestrian exit), the exit doors are at each end of the central bore

Fans will pressurise the central bore to prevent smoke entering the central bore when an emergency door is opened

Lighting within the central bore (pedestrian exit) will fully turn on Approximately ten seconds after a door is opened

The first emergency telephone within each bore is 50 metres into the Tunnel and every 50 metres thereafter

There are fifteen emergency telephones within the North bound bore, approach and exit ramps

There are fourteen emergency telephones within the South bound bore, approach and exit ramp

Source: https://jacklynchtunnel.ie/general-tunnel-information/

Hibernicis

https://www.boards.ie/discussion/comment/121824305#Comment_121824305

Good summary. The casting basin (dry dock) was enormous. A public viewing platform was constructed adjacent to Ringmahon road and it attracted a lot of attention. I didn’t live in Cork at the time but it was obligatory pitstop any time I was in the area. The tunnel elements were sealed at both ends and floated into position and then lowered into the trench. There is a great arial photo here showing the tunnel elements after the castin basin was flooded, but before they were towed into position. No Dronehawk back then.

Picture source: https://cases.ita-aites.org/search-the-database/project/140-river-lee-tunnel

Further photo of the first tunnel element with buoyancy attached being floated into plac. Tthe northern portal section had already been floated and positioned at this point. Note the beginnings of what is now the N40 in the background, and all the grass in Mahon.

Picture source: https://www.facebook.com/oldphotosofcork/photos/a.425019591263720/427120851053594/

Hibernicis

https://www.boards.ie/discussion/comment/121824338#Comment_121824338

I’m not sure that the central bore was ever planned to be anything other than an emergence escape route. Access and egress would be problematic if it were to be used as a pedestrian route under normal circumstances. The fact that the tunnel got built was a result of an amazing series of coincidences and the efforts of some extraordinary individuals. And it had a very narrow escape….. It was planned as a two lane tunnel (one lane in each direction) and went through the feasibility study and public enquiry as such. In order to drag out making a decision, the then Minister for the Environment (Mayo’s finest, the one and only Pee Flynn) ordered a second public enquiry and the outcome was an increase to four lane tunnel. Doesn’t bear thinking about the consequences had the original plan been pursued.

DylanQuestion

Although I was one of the people to walk (or be walked) through the tunnel on completion, I don’t remember it. How was the planning process around the tunnel? Did it drag on for years and years with debates about slight details? Were there many objections? It probably helped that there was probably nothing in terms of houses nearby east of Bloomfield at the time. It’s crazy that for such an old city, most of Cork’s growth has been since the 1950s

AugustusMinimus

https://www.boards.ie/discussion/comment/121826692#Comment_121826692

Your last comment is the same for every Irish city. Huge growth in all Irish cities due to both urbanisation and general population increases.

I would say that the likes of Limerick, Galway and Waterford have experienced even more rapid growth since the 50s than Cork did. Cork has a much larger old core than those cities.

marno21

I think in hindsight, had it been built as a two lane tunnel we'd have got a massive Westlink style upgrade during the boom years. It might have been done right the 2nd time to the point that the current Dunkettle setup might have been emulated back then like the M50 upgrade.

The tunnel now represents a massive single point of failure on the Cork strategic road network. Rather than any talk of widening it a northern Lee crossing with city bypass is the only long term solution. Were the tunnel to be widened it would just put too much pressure on the Douglas flyover, KRR & N22 at Ovens.

Hibernicis

https://www.boards.ie/discussion/comment/121826692#Comment_121826692

We are a bit off topic, however if it weren’t for the Rive Lee Tunnel there would be no Dunkettle Interchange, certainly not in its current form.

Cork in the mid 80’s was a severely depressed economic wasteland. Fords, Dunlops and Sunbeam all gone, no IT industry and the pharma sector was really just beginning to be more than the original 1969 Pfizer plant in Ringaskiddy. And the rest of the country wasn’t much better. The general consensus was that the country was broke and unlikely to change. The height of our industrual ambition was Willy McCarter’s FOTL in Donegal employing 3,500 making tee shirts and underpants. The Collins and De Valera bridges had just been opened (allegedly the first “non-replacement’ bridges built since the foundation of the State) and despite their small scale were regarded with awe. The state’s motorway network consisted in its entirety of the Naas Bypass, all 5 miles of it.

So when talk started about Cork getting a “downstream crossing” as it was referred to, with a high level bridge or a tunnel at Tivoli being the options, Cork people took little notice, regarding it as kite flying and having little or no chance of proceeding. And anybody outside Cork (i.e. Dublin and Kerry) regarded it as “notions” if they thought about it at all. There was no NRA or TII at the time, so no coordinated approach to planning and prioritising the development of the National Road Network (Shout out to Eamonn for bringing us back to this) so it was up to the local council to try to make things happen. It’s difficult to convey the lack of interest and skepticism that attached to the prospect of the bridge or tunnel. The fact that it did get approved, funded and built is down to a small group of resolute and determined visionaries who took the idea and ran with it, and who by fair means and foul outmanoeuvred the competition (ever other Council and Region in the country and the Department of Finance) and got their project approved. There were also a series of happy coincidences in terms of timing, particularly in the political and financial arenas that allowed the project to “slip through”. So rather than objections, debates etc I think it’s fair to say that the public attitude went from total skepticism about the project in the early days utter disbelief right up to the opening. It happened at a unique point in time, just as an Old Ireland was disappearing forever and the Celtic Tiger was nothing more than lust in it’s father’s loins.

More here: https://en.wikipedia.org/wiki/Jack_Lynch_Tunnel

niloc1951

https://www.boards.ie/discussion/comment/121826168#Comment_121826168

Ah yes. Well that slip is just that and it has no right of way over the M8 which it's joining. Traffic joining from the loop is 100% dependent on the courtesy of drivers coming down the M8.

Unfortunately most drivers don't understand the concept of being courteous to others.

KrisW1001

@Hibernicis The largest factor was the EU Cohesion Fund that allowed Ireland to pay just 15% of the cost of the tunnel. The Lee Tunnel was one of the first schemes funded under this programme.

hans aus dtschl

https://www.boards.ie/discussion/comment/121826995#Comment_121826995

Of course, agreed, but we're saying that people are breaking the speed limit on the M8 section, preventing people from merging safely. Others are also tailgating (another result of them breaking the limit). We're saying there might unfortunately need to be some enforcement.

hans aus dtschl

https://www.boards.ie/discussion/comment/121826680#Comment_121826680

Thanks for all the info and context. What you're explaining about political wrangling is is the piece that I was reading about last night, it's almost difficult for me to remember how bad things were.

How far we've come!

gooseman12

https://www.boards.ie/discussion/comment/121827083#Comment_121827083

Ya, I've had the same experience coming from the N8 loop. The cars coming straight down the hill from the M8 have no reason to slow down to 60. If everyone was doing 60 there would be no issue whatsoever on the merge, its all about the speed.

As someone else mentioned earlier, it really is a prime candidate for a fixed speed camera

jhegarty

There is video of proposed two tunnel mentioned above here : https://www.rte.ie/archives/2022/0110/1272861-river-lee-tunnel/

niloc1951

https://www.boards.ie/discussion/comment/121827205#Comment_121827205

The issue is down to a lack of courtesy, here in Ireland there seems to be a general attitude among drivers to actively make it difficult for other drivers to join the mainline from a slip road.

I do a lot of driving in western Europe and the opposite to the above is usually true. Drivers on the mainline will usually ease up or speed up to create a gap for joining vehicles. It's rear to have to slow down on the slip because there's no gap on the mainline.

hans aus dtschl

https://www.boards.ie/discussion/comment/121827599#Comment_121827599

Also some lovely images there of what I presume was LUTS 1978 too thanks!

I'm actually becoming disheartened to see how good LUTS 1978 was: we've had these visionary ideas available for a long time but have ended up with everything that LUTS tried to avoid. We got Dunkettle and the M8 and the N40, that's phenomenal, but it looks like almost everything else has slipped.

EnzoScifo

I remember there being a lot of controversy and even pictures on the front page of the echo claiming that toll booths for the tunnel were being installed before opening.

Hibernicis

https://www.boards.ie/discussion/comment/121834893#Comment_121834893

The original plan, back in the 80s, was for it to be tolled. I think it was to be 25p or something. This was necessary to fund construction. It became unnecessary when the Germans kindly decided to pay for our roads in the 90s. That of course hasn’t stopped the Echo dragging it up every few years on slow news days and that windbag Terry Shannon seeking voter enrichment from time to time by calling on “the minister to confirm that a toll will not be introduced” when there hasn’t been any mention of it anywhere except in his head.

cantalach

https://www.boards.ie/discussion/comment/121836676#Comment_121836676

Ah why did you have to mention Terry Shannon and wreck my chilled out Sunday morning mood…I felt my blood pressure jump right away.

DylanQuestion

A City Council Consultation has started about Special Speed Limit changes in the city, and it includes Dunkettle’s speed limits

https://consult.corkcity.ie/en/consultation/cork-city-road-traffic-special-speed-limits-bye-laws-2024

Looking at the map, it seems:

• Before the tunnel and in it will go to 80km/h
• 60km/h everywhere else except the N25 flyover where it will be 80km/h
• The M8 will go to 100km/h from the N8 slip lane

This only includes City speed limits. It doesn’t include what the speeds will be on the N25 in the County section (the boundary is just west of the dumbbell) but it seems to suggest it will turn to 80km/h there. I’m not sure where it will change to 100km/h and 120km/h

Chris_5339762

Isn't that pretty much what it is at the moment?

Not that any of them are ever enforced or obeyed in any sense...

jhegarty

I don't see any reason for the flyover not be 100 kph or for anything less than 80 after leaving the tunnel heading north.

DerMutt

I never thought I'd be suggesting an actual reduction in the speed limit but the section of Link C where it dips and turns under the N25 overpass is scary at anything close to 60 kph in a double deck artic! It should be reduced to 50 kph for that section or some poor trucker could end up on their side over the concrete barrier and on top of traffic exiting the tunnel heading for Waterford!

mackerski

https://www.boards.ie/discussion/comment/121849848#Comment_121849848

Could the trucks not just voluntarily drive more slowly to suit the conditions?

_Kaiser_

https://www.boards.ie/discussion/comment/121859023#Comment_121859023

This, and as a general rule too.

There's far too much dependency in this country on "someone else" to do the thinking/decision making for them.

Driver's should have the awareness and cop on to assess a given situation and react appropriately - sometimes that might mean slow down, sometimes it might mean speed up.

This infantalisation of society and lack of person responsibility/accountability is a big problem, as is the decision then to pander to this lowest common denominator and force everyone else to accomodate them.

Corkladddd!!

Interestingly I was told by someone today that I'd rely on for these things that there is acknowledgement within TII on the N25 to N40 connection being undersized for current traffic volumes and that while the captial project is closed the overall project will remain open with some potential on road upgrades to be considered. Would this be a zip merge?

jhegarty

Mad idea , but close the Little Island entry from 7am to 10am and send them this way :

https://www.google.com/maps/dir/51.9018725,-8.378833/51.8930864,-8.3922049/@51.9047031,-8.3903699,16.75z/data=!4m2!4m1!3e0?entry=ttu

niloc1951

https://www.boards.ie/discussion/comment/121866194#Comment_121866194

The idea of zip merging has had a lot of air time here already.

However, the fundamental problem of fitting two lanes of traffic from the N25 arriving at 100kmh plus a third lane from Little Island into one lane travelling at 60kmh will always lead to queueing once a certain volume of arriving traffic is reached, no matter how they are integrated into one lane.

The only way to reduce the queueing is either increase the speed of traffic through the single lane bottleneck that connects the N25 to the N40 which might compromise road safety or add a second lane connecting the N25 to the N40 which would require a another tunnel.

KrisW1001

There will always be queues at peak demand times. The interchange has reduced these queues overall, but that really wasn't its main purpose.

The whole point of this work was to stop heavy traffic on one approach to the interchange from blocking all the other approaches too. In this, it has definitely succeeded.

The other way to decrease the queuing is to give commuters an alternative to driving on N40 at all. Adding more lane capacity for private cars is a hiding to nothing: we could lay a second tunnel here, but then Douglas would be the problem. Knock down the shopping centre, widen Douglas, then we'd have "problems" at Kinsale Road again, and so on. And all those extra lanes just to achieve the same throghput as shifting 20% of car commuters to public transport.

niloc1951

https://www.boards.ie/discussion/comment/121869074#Comment_121869074

I'm a regular user of public transport, both bus and train. Several issues need to be addressed to encourage more people to switch from cars to public transport.

Busses are notoriously unreliable and one can have no confidence in arriving at one's destination at the expected time. In this respect, trains are a far better option.

The issue of loutish behaviour needs to be addressed, there is nothing worse than having one's personal space invaded by others playing loud music or video on their phones or regaling friends, and the rest of the passengers, with an account of the previous night's debaucherous behaviour..

KrisW1001

Agree that there's a way to go on Public Transport, but it's far cheaper than constantly building roads. Bus punctuality is a huge problem in Cork, and one that TFI seen to be doing very little to address. The "real time" data that feeds its apps should be a real help, not it is clearly based on estimates rather than real GPS data, and has frequent "phantom buses" that never come. Plus, buses can and do arrive up to three minutes before their due time: leaving a stop early is the worst sin for any kind of timetabled service..

Dunkettle was needed to remove a flaw in the road network (the single, shared point of congestion that was the roundabout). The next step here will be N40 North to relieve the South Ring, but there's nothing more that can be done effectively south of the river.

Hibernicis

From Roundabout to Interchange

Something for the next rainy day. A few recently published retrospective videos. While all are interesting, I found the interviews with Richard Bowen and Val Fox particularly revealing, giving an insight into managing the layering and complexity of the project.  

Dunkettle - The Ultimate Construction Timelapse - Part 2 (@dronehawk)

https://www.youtube.com/watch?v=nmXVkWrveyo

Dunkettle - The Ultimate Construction Timelapse - Part 1 (@dronehawk)

https://www.youtube.com/watch?v=S9FMc9uID8s

Dunkettle - (3 Years in 3 Minutes) (@dronehawk)

https://www.youtube.com/watch?v=IE-vbnUgNh0

Dunkettle Interchange Evolution during the Construction Period (TII)

https://www.youtube.com/watch?v=3zwBWSE7ZAc

Dunkettle Interchange Upgrade - Evolution during the Construction Period (TII)

https://www.youtube.com/watch?v=-tl3Uh7scLA

Dunkettle Interchange Upgrade – The Challenges faced during the project

TII - Interviews with Richard Bowen, Senior Project Manager TII, and Val Fox, Regional Director -John Sisk, the Main Contractor.

https://www.youtube.com/watch?v=atDqPWrSh9I

BagofWeed

https://www.boards.ie/discussion/comment/121869534#Comment_121869534

I spent most of the week on PT on the continent and I hate to break it to you but noise, music and conversation were the order of every trip. There were even folk drinking spirits on a train yesterday morn and you know what nobody gave a ****. Even the drinkers cleaned up and took their shot glasses when they arrived at their stop. There were loads of old school gabbers on the trains coated in tattoos and they were all minding their own business. Even the train conductors were chatty and being friendly and not looking down their noses at people drinking and listening to music, talking etc.

Ireland has become this horrible stuffy stifling place in the last ten/fifteen years.

niloc1951

https://www.boards.ie/discussion/comment/121872260#Comment_121872260

Nicely put. An excellent argument why many people are so reluctant to give up their own personal space free from the unwanted intrusion of others as is provided by the car.

BagofWeed

https://www.boards.ie/discussion/comment/121872650#Comment_121872650

Car is king. And none of what I wrote about was preventing other passengers from reading books or children commuting from school. Despite the fear and paranoia that runs through Irish life none of what I wrote about had appeared to intimidate or cause distress to any other passengers either. A sizeable amount of folk here are just anti people in general and will never fell safe around groups of people, no matter wheter it's on public transport or walking around a city/town centre. Got off at a metro stop in De Pijp and there was kids no more than 5 years old on their own getting onto the metro and I just thought there and then that back here people would freak at the idea of young kids using public transport on their own.

niloc1951

https://www.boards.ie/discussion/comment/121873420#Comment_121873420

Apologies for being so far off topic, but maybe it's not considering it's in a way about the ongoing traffic congestion at Dunkettle.

I do know that mass transport systems can be rammed full with all sorts of people, I've used them too, and in general people seem to be quite respectful of others and not at ail intrusive.

My point is, after a busy day the choice for the commute home is between the peace and quiet of the car while listening to your favourite radio programme or music or maybe having a quiet chat with your passengers against a seat, or maybe standing, in public transport while having to put up with the intrusions and sh1te talk from some fellow passengers who have no regard for others.

Chris_5339762

I will add also that despite all of the accidents at the N28/N40 merge, there is now absolutely no crashing happening at Dunkettle really. And importantly if one route gets blocked, it doesn't block the entire roundabout with consequences for uninvolved directions of traffic.

Remember the days when the N28/N40 crash would pile up to the roundabout, proceed to block the entire roundabout, resulting in traffic back to Sarsfield Road? Can't happen anymore, which is great.

crossman47

I am not familiar with this interchange but the signs sent me astray recently. I have to drive from Dublin to Carrigaline soon. As I come in on the M8 , is it straightforward to enter the tunnel to get onto the M40? Any advice welcome.

hans aus dtschl

https://www.boards.ie/discussion/comment/121879958#Comment_121879958

On the M8, just stay right.

After the tunnel, second exit for N28.

DylanQuestion

https://www.boards.ie/discussion/comment/121879958#Comment_121879958

Follow every sign for Westbound then, as hans said, take the second exit (J8) for N28 to Carrigaline. At the Bloomfield Interchange, keep following the signs for N28. At the next big roundabout (Shannonpark), which you should reach after ~5 mins if there's no traffic, it's the second exit (R611)