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

Victor wrote: »

How would they get to the roundabout? Are you suggesting the slip road that goes from the west (Cork) to the north (Dublin) be two-way? That would be a barrel of fun - not.

How would traffic get from the M8 to Little Island?

Give me a few mins to draft a map.

Hogzy,
There's a large industrial estate serviced by that slip road including all of Iarnród Eireann's freight depot. Also, a significant amount of the Glanmire and Glounthaune population use it. But realistically the freight depot is the biggest user of this. The image you drew even shows a little of it.

I don't disagree that the slip could be gotten rid of if the Little Island junction was improved. However, the Little Island junction has not got a lot of extra room on either side and backs up considerably at peak times as it is, on the "old" road and within Little Island.

In terms of comparison with the other roads concerned, it certainly is the least significant, but I think you really need to see the numbers before you can say the Little Island junction could survive the extra traffic. IMO it wouldn't.

But look, my point over all others, the proposed dumbell interchange east of the dunkettle interchange is inadequate for intercity traffic.

Irish and Proud wrote: »

Hi folks,

There's now a brochure (PDF File - 1618KB) by Jacobs on the preferred option.

Regards!

Great to see this progressing but doubt funding will be in place to pay for the CPOs.

I would prefer that version of the scheme NOT to progress.

I think munchkin and others have made excellent points about the M8 - Cork City traffic clashing with traffic into Little Island. I mean, obviously there's been a lot of work put into the plans by experienced people, and we don't know what the current and predicted traffic volumes on those routes are, but from observation and from experience I can't believe that the (aptly named?) dumb bell junction will be anything but an impediment to traffic and probably downright dangerous.

Does anyone know of an official petition against the current design? When is it supposed to be going for planning approval?

I think the design has to be modified to make traffic into Little Island and from the M8 to Cork City free flow. What I think we need is bollards! Lots and lots of bollards. I've gotten the crayolas out again, but this modification is fairly counter-intuitive so bear with me....

[edit] I've thought about it and think I can make it simpler - new drawings in new post. [/edit]

^^^

The little island junction you decided to move has absolutely no effect on Dunkettle.

Its the Glaunthaune Junction thats the issue.

Yeah - would be nice, but I'm guessing it'd be fantastically expensive to build and cause massive disruption. With the purple and others you're also looking at a lot of elevation changes in a short space.

@Chris - I don't think it'd be viable to lose the entrance/exit to Little Island there. It'd have a huge effect on traffic in Little Island. Glaunthaune would see less traffic, but there's plans to increas the traffic volume there too.

Blitzkrieger wrote: »

I was thinking about it this morning and I think I can make things simpler. My goal is to stick as close as possible to the preferred option, but I think the M8 traffic has to be made free flow. I think this can be done simply by introducing a contra flow on the bridge, changing the shape of some of the roads and moving the 'dumb bell' roundabouts a bit :

https://us.v-cdn.net/6034073/uploads/attachments/555/195603.png

https://us.v-cdn.net/6034073/uploads/attachments/555/195604.png

https://us.v-cdn.net/6034073/uploads/attachments/555/195605.png

https://us.v-cdn.net/6034073/uploads/attachments/555/195606.png

The problem with each of these is that they are too tight in horizontal and vertical curvature.

spacetweek wrote: »

Great idea. What you're proposing in effect is a U-turn lane. U-turn lanes are common in countries like Thailand and the United Arab Emirates. Here's an example.

Perhaps not the easiest to use with a truck.

I independently had this idea, but in my version the U-turn flyover is not incorporated into the Little Island junction. It would be either between Dunkettle and LI or east of LI:

Between Dunkettle and LI
Advantage: Short journey
Disadvantage: Space is tight, vehicle speed would have to be very low
East of LI:
Adv: Lots of room to build, so loops aren't so tight - vehicle speed is higher
Disadv: Long winded journey

I've mocked up a quick map.

To be practical, this would need to take a much wider curve. Note the 30km/h speed limit on the N3-M50 junction that is causing problems.

spacetweek wrote: »

Where is that exactly?

I think ton the West to south slip road.

Victor wrote: »

The problem with each of these is that they are too tight in horizontal and vertical curvature.

The way I've drawn them, probably. In some ways I might have stuck too close to the original design. You could probably adjust the curvature on the approaches to the bridge on the east on both sides of the N25 with (hopefully) minimal impact to the design. Space is always going to be a concern, but I think you could get them to a point where you could have a 80kph limit. If you look at some of the mad cow interchange, 60kph could be a realistic goal too. I was trying to avoid it, but I think moving the bridge a little further east and changing the shape of it could help too, but might force a bit of re-jigging with the minor roads around there too. If I get a chance I might get the crayolas out again later and see if I can illustrate it better.

Victor wrote: »

You don't need a petition. Just write to them explaining your concerns.

An Bord Planala or the construction company?

The two main problems I see with the design I've illustrated belown. The first is that with so much traffic from the north side of the interchange using the dumb-bell roundabouts, I'd worry that the traffic would back up all the way to point A. This would mean traffic blocking slip roads and causing hazards. But even if traffic didn't back up that far, where you get queues, you get queue skippers. Muppets driving down the outside as if they're going to the N25 then cutting in at the last minute would be a danger too.

I'd also worry that muppets would think the yellow route would be the path from the city to Little Island/Glounthaune. I'm guessing there'll be pletty of road markings to discourage it.



So I've had another go at drawing out a solution. Again, yellow indicates barriers between contra flow traffic and hopefully green arrows illustrate traffic flow. Some of the curves are not what I'd like them to be, but maybe somebody who knows what they're doing would be able to do better.

In this version I've moved the Glounthaune slip road to the other side of the "U-turn lane". This means we'd have to build another bridge but gives more room for the U-turn lane. The curve at the end of the U-turn lane to take traffic into Little Island is also a bit sharp - it probably could be moved or re-drawn to be smoother.

I've also given no provision for traffic from the N25 or Little Island to Glounthaune. At the moment this traffic uses the tunnel roundabout, going all the way around to get to Glounthaune. In my version something similar happens - traffic goes all the way around the interchange to get to Glounthaune. Alternative solutions for including these traffic flows can be seen in my earlier posts.




I would also propose building a new slip road to point B, rather than opening up the old road all the way to Glounthaune and bringing city-Little Island traffic that way. I think this would be cheaper and simpler than building all those bridges, and I think the extra traffic could safely merge between B and A.

An advertisement was in yesterday's Irish Examiner notifying of the application for a motorway improvement order and EIS for the scheme

details at www.n8n25dunkettle.ie

FullBeard wrote: »

Some excellent CGI of the proposed changes after completion superimposed onto existing aerial photographs here: http://n8n25dunkettle.jacobs.com/docs/32102066%20Dunkettle%20EIS%20VOL%203%20Figures%20-%20Fig%201.1.1%20to%20Fig%202.4.1.PDF

Nice images indeed. I like the way they used photos of the current set up which includes heavy tailbacks in all directions, and the superimposed images have no tailbacks at all.

The Oral Hearing is now ongoing

Interchange upgrade ‘vital for growth of Cork’
By Sean O’Riordan
Friday, November 16, 2012
An upgrade of the Dunkettle/Jack Lynch Tunnel interchange is "vital for the growth of Cork", a Bord Pleanála oral hearing was told yesterday.
In the event of the proposed €90m upgrade being approved, it would signal the commencement of other major projects in the region.

To date, traffic congestion has been a setback to new projects.

Cork County Council’s senior planner, Andrew Hind, said the improvement plan was vital for Cork.

He referred to the Port of Cork’s plans to build a deep-water terminal in Ringaskiddy which were previously rejected by An Bord Pleanála amid concerns the extra heavy goods traffic generated would prove too much for the already over-capacity junction.

Mr Hind said he wanted to see a multimillion-euro housing project, proposed by O’Flynn Construction at Dunkettle, proceed. It was rejected by An Bord Pleanála for the same congestion reason. <snip>

Around 30 known archaeological sites are dotted around the designated project area, most of which are post-medieval.

NRA experts said they would carry out "test-trenching and metal detector surveys" to establish if there were other sites of interest.

Dr Jervis Good of the National Parks & Wildlife Service made recommendations to An Bord Pleanála inspector Jane Dennehy, which he said would ensure that otters and little egret roosts on the Glashaboy Estuary are protected during construction and thereafter.

http://www.irishexaminer.com/ireland/interchange-upgrade-vital-for-growth-of-cork-214124.html

From the sounds of it the NRA are able to accommodate any requests from interested parties in ensuring businesses and residents are being looked after.
Well, the residents were chancing their arm looking for double glazing for their houses but they dont seem to be getting that, but rather a silent smooth surface on the road that reduces noise.

BTW: theres a road round the corner from me with it recently installed and the quiet surface is indeed something to behold. Theres a much lighter zipping noise compared to the louder deeper rumble of the regular surfacing.

Medium to long term plans for that is to replace the Dunkettle Roundabout with traffic lights.

[For those that dont know the Dunkettle Roundabout (where the Tivoli DC interacts with the north road to Glanmire) is different from the Dunkettle Interchange which is where the M8/N25/N40 go together]

The Dunkettle Roundabout as it is is really stupid. You have tonnes of traffic coming out of Cork which has to give way at the roundabout to far, far fewer cars coming from the N25 east going to Glanmire. Its just silly.

So the Oral Hearing was last week.

How long more, typically, would it take ABP to announce their decision?

Good News - This has been approved by ABP

http://www.irishexaminer.com/ireland/100m-dunkettle-interchange-project-given-green-light-231374.html

An Bord Pleanála has given the green light to National Roads Authority (NRA) plans for a €100m upgrade of the Jack Lynch Tunnel/Dunkettle interchange.


The board voted by a three-to-one majority to approve the scheme, at one of the country’s busiest junctions.

It also approved the issuing of Compulsory Purchase Orders (CPOs) which are required as the NRA needs to acquire land to construct some elevated new slip roads.

More than 90,000 daily vehicle movements have been recorded at the junction.

An Bord Pleanála agreed with an NRA submission that an upgrade was needed to alleviate the level of congestion currently being experienced at the junction during peak times.

Despite some objections, the board felt the proposed development would not be likely to have any significant adverse effects on the environment.

The board, however, imposed a number of conditions.

They include a proviso the NRA carry out a number of mitigation measures to ensure no adverse impact on flora and fauna in the area.

Automatic traffic counters will also have to be installed in the area and the NRA will be required to carry out a review of traffic flow at the planned upgraded junction every two years.

Plans for a proposed cycle path on a section of the upgraded junction have been refused because the board considered it could contribute to accidents.

An oral hearing took place at the Silver Springs Moran Hotel over two days last December.

At the hearing, the NRA’s team of experts argued congestion was costing the State and the upgrade would save commuters a significant amount of time.

The plan involves creating a number of dedicated local access roads around the junction, thus separating those making local journeys from regional and national journeys.

The signalised roundabout at the northern end of the tunnel will be removed for total free flow and a dedicated slip road will be built on the city side of the tunnel so traffic can directly access the northbound lanes of the M8.

NRA spokesman Sean O’Neill said he welcomed the Bord Pleanála decision.

“We would like to move forward on the scheme but it is subject to funding being made available. It will cost in the region of €100m,” he said.

The decision is also likely to be welcomed by the Port of Cork which was refused planning permission by An Bord Pleanála for a major new cargo-handling terminal in Ringaskiddy. The main reason for the refusal was the increased HGV traffic this would generate would have further impacted on tunnel congestion.

The port authority, meanwhile, is about to resubmit planning for a scaled-down terminal in Ringaskiddy.

Great news. I can see this progressing quickly, due to it being Corks version of Newlands Cross. Once the Sarsfield/Bandon flyovers are done, the impetus will move to this.

Shame that the provision for cyclists is gone, it would be great to have a cycle lane from the city to midelton. Im sure there a good few in little island and carrigtwohill working there that would enjoy the challenge of a cycle.