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

Excellent news. This is the second most important scheme in the state after the M7 widening.

One thing though. The Douglas flyover is a 2 lane road with AADT figures of circa 70,000. The only thing saving it westbound is that the present Dunkettle is reducing the effect of rush hours and spacing rush hour over a longer period.

Cars will be queuing out the end of the tunnel from Douglas when the Dunkettle scheme opens.

marno21 wrote: »

For a city of Cork's size the volume of traffic using the south ring is obscene. 100k vehicles daily between J6 and J7 is absolutely ridiculous all things considered.

Stating the obvious really but if you want to get from the M8 or N25 to the west of the city, it's practically your only option apart from spending half the day negotiating the city.

JupiterKid wrote: »

For a small city of just over 200k population, I think it’s shocking that the JLT is caring an AADT of close to 70,000 vehicles.

A damning indictment of dire public transport and poor urban planning if I ever saw it.:mad:

It says more about the geography of Cork and the importance of the tunnel.

It also shows that there is little forward thinking in this country. This will cost 100m to fix. At the same time, we built a 3 stack Roundabout at the M17/M18/M6 junction. Crazy.

Cork Truck Driver wrote: »

AugustusMinimus wrote: »

we built a 3 stack Roundabout at the M17/M18/M6 junction.

That is an impressive bit of work though having travelled it.

A partially unrolled cloverleaf which would have given much higher capacity and a cheaper build would have been much better though.

There was originally supposed to be a service station at this Roundabout. The station was removed and bizarrely the junction was maintained.

Most European countries would automatically put a stack on this type of junction, irrespective of traffic levels.

JupiterKid wrote: »

For a small city of just over 200k population, I think it’s shocking that the JLT is caring an AADT of close to 70,000 vehicles.

A damning indictment of dire public transport and poor urban planning if I ever saw it.:mad:

It also shows the reality of commuting and that the city has an influence well beyond any proposed boundaries. The commuter belt is probably close to double the number you mentioned.

mire wrote: »

Am i right in my interpretation off the scheme drawings that northbound tunnel traffic heading to Dublin will be reduced to one lane for the course of the intersection? Is this 1. correct? 2. A problem, in reducing this flow to one lane?

http://n8n25dunkettle.jacobs.com/docs/32102066%20Dunkettle%20EIS%20VOL%203%20Figures%20-%20Fig%201.1.1%20to%20Fig%202.4.1.PDF

I doubt more than 50% of traffic goes SRR to M8. Can’t see it being an issue even in peak traffic.

grogi wrote: »

AugustusMinimus wrote: »

I doubt more than 50% of traffic goes SRR to M8. Can’t see it being an issue even in peak traffic.

Majority of traffic from SRR turns East toward Midleton. The proportions might change in far future when NRR is opened though and south side goes through the tunnel, M8 towards NRR and finally N20.

Still though, I doubt only having one lane for SRR to M8 will give much of an issue especially given that SRR traffic will be split into 3 different streams going through Dunkettle

SRR to City
SRR to M8
SRR to N25

You would want maybe 60% or more of SRR traffic using just one movement before you would see anything noticeable. The reduction in speed to 50 or 60kph at the junction will also increase capacity versus what the SRR handles at 100kph

mire wrote: »

AugustusMinimus wrote: »

Still though, I doubt only having one lane for SRR to M8 will give much of an issue especially given that SRR traffic will be split into 3 different streams going through Dunkettle

SRR to City
SRR to M8
SRR to N25

You would want maybe 60% or more of SRR traffic using just one movement before you would see anything noticeable. The reduction in speed to 50 or 60kph at the junction will also increase capacity versus what the SRR handles at 100kph

thanks for the replies; not sure though. the cork metropolitan area is planning to grow very significantly to 2050, how about future proofing the infrastructure? this SRR-M8 movement is likely to experience growth, substantial growth.

I think the fact that the tunnel is only 2 lanes in each direction was also taken into consideration when doing this junction.

I doubt it will ever be widened to 3 lanes as the cost would be enormous. This will be the limiting factor on capacity rather than the junction.

Alternative options will be put in place. Bridge by Pairc Ui Chaoimh. North Ring Road. Possible further down stream crossing (Rushbrooke to Passage West)

Carawaystick wrote: »

I presume a safe cycling route to get through this junction is the first thing being done here...

There is mention of cycle infrastructure in the EIS document. Particularly on page 12 or so, it's listed as the 5th priority of the upgrade (after improving capacity, minimising impact, segregating local and strategic traffic, and mimimising weaving).
To this end they mention
"
It is an objective of the scheme to ensure that any solution also includes the provision of pedestrian and cyclist connectivity through the proposed scheme. This facility should coincide with other planned pedestrian and cyclist facilities in the area and also separate these movements from the main traffic movements through the interchange where possible. This objective therefore promotes more sustainable transport modes and will also assist in accessibility between the various areas currently severed by the existing interchange"

You'll find the drawing of this aspect of the design on figure 2.1.1.

Their plans are for pedestrians and cyclists to dash across the Cork-Dublin slip road. When I pointed this out to them they advised me that since traffic would be going at 50kmh it would not be a problem.

Speaking as a cyclist who currently uses the interchange, I believe that this design will very effectively move all cycle traffic away from the Dunkettle area and end cycling as a mode of transport through this junction once and for all.

marno21 wrote: »

In most areas these roads would be motorway, they are in Dublin (you won't find cyclists or pedestrians on the M1, M4, M7, M11 or M50). They realistically should be and in the case of the N22 and N25 will likely become motorways when they are extended to Macroom and Youghal respectively. They are no place for cyclists, cyclists should not be crossing 120km/h on/off ramps at grade. Cyclist facilities should be provided on either the roads they replaced or totally segregated.

If you live in Swords you don't cycle to Dublin via the M1. The same should apply in Cork with the N25.

How do you cycle between Glounthouan or Little Island to Cork? It's not like there's the old road to use like from Swords to Dublin.

The NRA have failed in their mandate to provide the safe cycling infrastructure up to now, and should provide it as the first stage of construction works.

Ideally you’d have a cycle track alongside the railway going into Little Island and then over into Glounthsune.

Cyclists should not being going through that junction.

spacetweek wrote: »

Aren't they reattaching the previously severed old road? That would be your east-west cycle route and cyclists should be going north-south anyway since that would put them in the tunnel.

Unfortunately if you check figure 2.1.1 you'll see that cyclists and pedestrians will share a footpath and then cross the Cork-to-Dublin slip-roads which will be free-flowing traffic. When I asked about this during the consultation they said that there won't be a bridge or underpass, but since traffic will be going 50kmh it should be fine. This is what I meant when I said that it will effectively render the area unusable. More serious cyclists will likely take the 4km detour through Glanmire, whereas casual users and commuters will simply be deterred. Pedestrians are almost non-existent since the previous tunnel interchange, when no dedicated pedestrian route was provided.

I agree with you that the old road would be an ideal east-west cycle route (it's a real shame it wasn't used as such in the current layout).
I also agree that no north-south movement has ever been facilitated. Discussion on the that can definitely be facilitated elsewhere.