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

Where you say "the join between N40/N25E and the N8 North roads will be tapered in such a way that traffic coming from the tunnel will be allowed move right onto N8 North, but traffic that originated from the West has no way to cross over, and must continue onward to N8." that's exactly my concern area. It looks like there are three potential flows joining together at your left-hand pink dot. If that's cut to two, it's much more manageable.

I have secondary concerns about this same junction: Glanmire/Glounthaune traffic will come through it too and I believe it will be quite busy. So I don't think North Cork traffic towards the city is going to choose the M8 when this upgrade is complete, I believe they'll still rat-run through Rathcooney etc. Ultimately, I think when this one's done, we'll still have a North-Cork to City problem.

It's also the active transport route through the interchange! The only improvement I can think of would be an overhead route from M8 southbound through towards the Glashaboy river. It would need two new structures, and the one at the West would be quite complex.

As far as I can tell, the blue coming out of the tunnel will be 2 lanes, right along to C. Orange will be one lane. But I would like to see the proposed lane arrangements for sure, thats the sort of detail we haven't seen just yet.

Of course, it might be somewhat self-sustaining, if traffic is bad at that dumbbell, people might just see it and go along to the Little Island junction.

You've drawn it perfectly and confirmed my thinking also: it's point A to point B in your drawing that I'm most concerned about.

My secondary concern is then the red traffic flow which crosses the bridge over the N25. It's drawn in red on the incorrect side of the bridge but that's immaterial, the point is that it will be Dublin, Cork, Mahon, Glanmire and Glounthaune traffic sharing that bridge lane and I expect it to be quite a heavy flow in the mornings.

Combine these and you get: bridge backed up, slip lane backed up, tunnel backed up.

This is just an observation, I haven't done any mathematics whatsoever and I hope I'm wrong about it!

Chris_5339762, I don't think the tunnel traffic will be able to "see and avoid" if the weaving Dublin-origin traffic clogs point B above: the tunnel will cease to function Eastbound.

I think the only way that this can happen is if traffic is leaving Little Island blocking the upper roundabout, if traffic on the new Little Island link road itself stops, or if there's a crash due to weaving between A and C above.

Great work Kris! You're right, the third lane there will take away a LOT of the problem. I had thought it was two, and that was a major part of my concern!

The busyness of the interchange works is inversely proportional to the busyness of this forum.

I think this also is a facilitator to remove the existing "Ibis" slip road beside M8 Southbound. That slip road needs to be removed reasonably urgently to facilitate other works, so focusing urgency on the movement you've highlighted.

With my "sustainable transport" hat on, it will be an important movement also, as it will be the first cycle route directly into Little Island. It's unlikely this cycle route will get much use in the short term, but in the medium-to-long term, there will be some "on-road greenways" from Glanmire to Dunkettle, and it will be a viable commute for some current drivers. You can imagine, for instance for people in the new Ballinglanna estate, that this will cut 2km or so off their 5km journey. That's a big deal. It will also for the first time facilitate buses into and through Little Island as a viable commuter bus route. There was a proposal also to have a "shuttle" route from the Train Station through the Island and back via this interchange, but I don't see this happening in the short term.

To add to that the entire interchange (apart from the old slip into Glounthaune) is still in-situ. It may be complex now, but when they do the diversions to build the bits on the current footprint of the interchange, it'll be even more complex.

That is the long-term plan, yep. South of the Glashaboy bridge, and South of the Tunnel Management building. The route will be viable but it looks like an opportunity to de-traffic Dunkettle will likely be missed. Obviously very far into the future, but some challenges that will need to be dealt with are:

The route will be on the boundary of the harbour SPA. It will be resisted particularly at the mouth of the Glashaboy River.

The route through Tivoli will be complex: there will be a P&R and it will be a dense urban area. I have low confidence in the ability to deliver a route of quality through that.

In draft Tivoli masterplans to-date there have been a mix of a direct "transport" route and an indirect "scenic" route along the shoreline. Where it's been "direct", it has been a "tag-along" to the primary motorised vehicular access. It's likely that a BOTH a "tag-along" direct route and a "scenic" shoreline route will be delivered, neither of which will work well for transport.

The link eastward from Dunkettle interchange to Little Island is currently of low quality and will need to be upgraded.

Finally, there is a plan to add a new river crossing from Centre Park Road to the Millennium Garden (Tivoli) and I believe that this movement will be a key part of delivery of an East-West corridor. The proposed design of this is a bus corridor with "tag-along" cycle lane to the motorised vehicular access.

From a Dunkettle perspective unless we upskill big time in active transport infrastructure design we're going to struggle to get meaningful modal shift. More cars will certainly come through Dunkettle from Tivoli. Cars, buses and trains. The opportunity is available to create a model "active transport" area but I don't think we'll see that opportunity materialise. At this point it's more likely that we'll get good mass transit in the area.

Sorry for digressing so much, but in fairness it does heavily concern Dunkettle.

I'm expecting the new Little Island West dumbell interchange bridge to start getting its the beams installed before too long.

The upright pillars are all nearing full height by the looks of it.

I was able to have a little more of a look at the new M8 bridges over the railway line, and there's still a good bit to do on both of them from what I can see. There's not enough earthworks on either side and certainly no blacktop on the bridges themselves. So a bit more to go there. The widening of the M8 L2998 bridge is ongoing, but looks like it's well over half-way, to my untrained eye.

Pretty sure I passed two of them on trucks at the site last night. It was a hive of activity around 10pm.

Next beams to be done tonight. It seems like they're progressing at a good rate, would anyone know is it ahead of schedule or as expected?

That's the pic in the email anyway, no drone video within the email.

Yup, beams are in place on the westbound N25 now. Looks a bit weird, half a bridge!

New bridge beams have appeared over the N25 Eastbound over the past few nights, and gantry frames have gone up on the N40 West and East between Mahon and the N28 junction. They look flimsy at the moment!!

Don’t know what the timeframe is but that bridge now looks in a very advanced state. I think we’re not far off it being used. The work to move carriageways is already being undertaken 400m up the M8 with the widening of the bridge over the L2998 and the surfacing of the widen central median.

Suspect the N8 East to M8 North slip will be opened soon too.

Would suggest signing up to the weekly update email on its website. Great email every Friday.

Looking at the pics in todays email, we are very close to that new slip being opened.

looking at plans, assume they’ll demolish the present road alongside the new bridge. They will then build one more bridge beside it?

Email today noted that the new mainline bridge will begin to be used from early 2022 onwards.

I think they'll just move the traffic lights slightly and stop southbound traffic on the roundabout at the new location. Northbound I suspect will work the same as it does now, at least for the time being.

Indeed. A lot of the old architecture will have to be demolished to make way for new movements so a phased transition is required.

I think the N8 east to N8 north slip will open soon after Christmas. Probably a few weeks after the new bridge starts to get used. Will just require tie in with the existing M8. This will open up a new access route which will help with temporary traffic rerouting.

the bridge carting the slip from M8 South to the new 4/4 dumbell interchange is also nearly there. Suspect this might get opened in the new year to allow M8 South to Glounthaune movement.

Isn't it that M8 South to N25 East slip will open first, they'll move all the southbound onto the new bridge and move the M8 North carriageway a bit east, allowing the N8 east to M8 North slip get finished? Will be great to see the progress and how they link it all in, my head melts trying to figure it out

Those are for the M8 east to N40 south movement I think.

Short new drone clip of M8 South to N24 east

Construction Tetris!!