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

AugustusMinimus

https://www.boards.ie/discussion/comment/123071644#Comment_123071644

Where did I mention anything about speeding?

Exiled Rebel

https://www.boards.ie/discussion/comment/123101994#Comment_123101994

By all means explain your comment.

AugustusMinimus

https://www.boards.ie/discussion/comment/123103357#Comment_123103357

I misread your post. I thought you were offering it as a solution to improving traffic flow through the Dunkettle Interchange.

EurasiaEndtoEnd

Hi all,

Living overseas and used to love taking a glance at the Dunkettle Traffic Cams to see how the project was going and also to see the weather in my hometown, Cork ! Does anyone know if the live feed is supposed to come back or is it curtains for that location? The feed went down after the big storm a few weeks ago and came back as static shots and now there is nothing to see.

Appreciate any replies.

Regards, MJC

niloc1951

I see the JLT route will be completely closed in both directions again for maintenance work this week.

I'm currently travelling in Spain where road tunnels are two a penny. I've come across quite a few where one bore is closed for maintenance with a contra flow operating in the other.

Why is this facility not used when maintenance work is required in the JLT, instead of completely closed the route and redirecting traffic through the city centre.

Leatra

https://www.boards.ie/discussion/comment/123342076#Comment_123342076

You'd really wonder. There's very clearly provision for it at each end of the tunnel with a break in the central median, but (per Google Streetview) that's been in-filled with wands and a plastic bump that looks semi-permanent. Yet another instance of a needlessly poor road management decision overriding the initial, well thought-out design.

KrisW1001

https://www.boards.ie/discussion/comment/123342757#Comment_123342757

This is the well-thought out version of the plan. There's only seven hours of possession every night. Traffic management to set up the crossover would take about an hour, tearing it down would take another hour, so to do the 21 hours of scheduled work would require four closures, not three.

But it’s not just that: traffic along N40 is minimal at night, and these works are on the lowest-traffic nights of the week, but that also means that people tend to drive faster. Making one of the tunnel bores two way sounds like a great idea, but if there were an accident, a head-on collision inside that tunnel would be catastrophic.

The crossovers are there if a long-term closure of one bore is required (or to allow emergency services to pass the “wrong” way down the tunnel for access).

Between 2100 and 0400, using the N28 South Link/ N8 Tivoli isn’t exactly a hardship. People will live, but I suppose the likes of the Daily Mail and the Sun need to frame this as an injustice, given that there’s clearly nothing bad happening anywhere else in the world.

Chris_5339762

https://www.boards.ie/discussion/comment/123342913#Comment_123342913

It was a right royal PITA last year when there were roadworks at the Elysian at night too.

I think they would contraflow if they could but if this is electrical works then I can understand just get it done.

If you look at it, all of the lighting in the tunnel are old skool fluorescent lights too, so they need to go.

niloc1951

Apart from the set up time it's also a safety factor. That makes me think I'm far safer in a Spanish or French tunnel with a contra flow in operation that in an Irish tunnel.

Also, if it really is a road safety issue how come conta flow is used in the N18 Shannon River tunnel

hans aus dtschl

https://www.boards.ie/discussion/comment/123362934#Comment_123362934

The issue, as far as I remember, was to do with blowing smoke/fumes in a particular direction causing significant problems with contra flow. I don't remember the full details of this I'm afraid. All I remember is that there was a crash and the subsequent investigation concluded that contra flow was to be avoided.

Charles Babbage

https://www.boards.ie/discussion/comment/123342076#Comment_123342076

There is zero value attached to additional time spent by citizens when there is roadworks, so as a consequence these are run for the convenience of the contractors etc. Divert 1000 people at €25/hour (the median salary) and there is a significant cost to people who is not mitigated.

KrisW1001

https://www.boards.ie/discussion/comment/123367651#Comment_123367651

There is a calculated cost notional cost of roadworks on the economy, and it’s not zero. Travel to and from your work does not come out of your salaried employment, so what’s being lost is the opportunity cost of leisure time, not employment. The exception, of course, is people who must travel as part of their work, but they’re not the ones commuting at peak times.

The cost of works is pretty much always far higher than these notional costs to the public, so it’s better to get the roadworks done as quickly as possible rather than draw it out over a long period. Politically, this is also true: people quickly forget about two or three days of stopped traffic, but they will remember enduring weeks of slow traffic.

SL01

I haven't read through this thread in its entirety (yet!) but what I've read so far is very interesting. I travel this route every day (N25 / N40) and have experienced the myriad of issues people are talking about. I have a question - travelling westward on the N25 (after J2 Little Island) and before the exit for the Tunnel / N40, there is a gantry that looks like it was supposed to have an overhead sign, but to date, it's empty. Could this be a mistake (i.e. wasn't meant to be there in the first place) or an oversite (they forgot to install it)? It certainly looks like it should have an overhead sign and indeed one would be very useful there! (picture from Google Maps - quality not the best)

SL01

Also, one other observation that I would like people's opinion on. A number of comments here mentioned drivers changing lane in the tunnel (very dangerous of course). One thing I have noticed it that there are no "No Overtaking" regulatory signs approaching the tunnel. Granted, there are solid white lines, "Stay In Lane" markings and a VMS with the same message but I think a regulatory sign like the one picture might deter at least some drivers from lane changing. Also (and I'm no legal expert) if there were an accident due to changing lanes, the driver involved (or rather, their smart lawyer) could argue that without the "No Overtaking" regulatory sign…. etc. etc…

No Bills

https://www.boards.ie/discussion/comment/123386722#Comment_123386722

It looks like that gantry has been in place for many years. Here's a screenshot from Google Maps dated 2009:

SL01

https://www.boards.ie/discussion/comment/123386763#Comment_123386763

OK, thanks. That explains it!

niloc1951

I'm just back after travelling over 13k km's through 9 countries. Compared to where I've been these are my observations about 'back home'.

The JLT is a joke only equalled by the standard of driving by its users.

Tailgating and unsafe lane changing here is so commonplace, it's little wonder we have crashes almost daily on the N25/JLT/N40 complex.

Indicators seem to be so precious that it's important to use them as little as possible.

As regards contraflows, such facilities are so commonplace that they are the norm when any work is being carried out on the other carriageway.

Single-bore two-way tunnels are also common, even the world's longest road tunnel, 27km, is a single-bore.

Today, there was another crash in the JLT. It's about time a double white line with rumble strip was installed from the convergence of the M8/N25 to at least 200m beyond the south portal. At the same time, traffic cameras need to be installed to aid the prosecution of offenders who change lanes across the double white lines. Currently, it's at least 3 penalty points and €80 for crossing a continuous white line.

Secondly, there should be a regular presence of unmarked Roads Policing cars cruising between Midleton and Bishopstown, ready to pull drivers who insist on trying to polish the rear bumper of the vehicle in front. Currently, it's at least 3 penalty points and €160 for failure to leave an appropriate distance between you and the vehicle in front.

hans aus dtschl

https://www.boards.ie/discussion/comment/123645515#Comment_123645515

Just to add to that, the traffic rat-running Southbound by going M8-N25-M8 and Westbound by going up and down the new Little Island West interchange slip roads and Westbound going from Little Island East through Glounthaune, and then back onto little Island West interchange to rejoin is also causing chaos. I'm not really sure what the solutions here are but we're having secondary and tertiary tailbacks all over the place related to M8 and N25 every time the tunnel traffic stalls.

Obviously we really need to reduce the number of cars on the N25, but also it would be great if we could engineer simple solutions to some of the rat running too. I've had a few near-misses on the greenway because of rat running on traffic jam days, it's going to end in tears at some stage.

Markcheese

Just back from the tunnel southbound at rush hour - people are kind of starting to zipper merge , not everybody is ,and there's still too many lanes all splodging In together , but the traffic moves easier if everyone merges smoothly - and the design really doesn't help that ,

Also the tight bend just before the tunnel doesn't help -and theres plenty paved space for the bend to be less tight , if the merge points are moved back ,

Plus rumble strips , or mini bollard or something to encourage people not to change lanes just before the tunnel

niloc1951

There is talk and apparently planning to build a bridge for the Cork LUAS project in the area of Water Street. If the planned bridge goes ahead, as is likely, and everyone is okay with closing the city sections of the river to maritime traffic, why not consider building the second bridge 4km further east in the vicinity of the JLT?

IIRC, a bridge was one of the original ideas, but lost out to a tunnel as it would be too disruptive to the maritime trade the city enjoyed at the time.

Such a bridge would provide added connectivity between the N8/N25/N40/M8, and its presence would have little additional negative effect on an already closed-off, by the LUAS bridge, city docks area.

Currently, the JLT is an absolute embarrassment, plagued by near-daily crashes, which seem to rule out any idea of vehicles using it at more than the current average of about 50km/h. If, and it's a big if, drivers were competent to navigate the tunnel at the posted 80km/h, maybe we wouldn't be experiencing the daily extensive queueing on either side.

Despite the €215 million upgrade to the interchange, the tunnel remains the choke-point and hindrance to timely commuting and business connectivity it always was and will continue to be until additional capacity is added either under or over the river.

Kermit.de.frog

https://www.boards.ie/discussion/comment/123748303#Comment_123748303

Very likely within 5 - 8 years we'll be seeing designs here for an additional crossing. Whether that's a tunnel or bridge remains to be seen.

A familiar story with infrastructure across the country is that it tends to be what's the least they can get away with and they messed up here.

EnzoScifo

would more likely be some sort of public transport/active travel crossing than another major crossing. There is currently a lot of sustainable travel works going on in Little Island including bus gates from the east through to Eastgate and onwards to the west. The new bus network also envisions Little Island being the terminus of a southern orbital service though Mahon, Douglas, Black Ash, ballyphehane, CUH and MTU.

Maybe a mixed bridge crossing with enough lanes for N40 traffic going Northbound along with dedicated public transport lanes and active travel. Then make the existing tunnel southbound only. Similar to the Dartford crossing. Would cost a bomb though.

cork_south

Cork needs a full 360 degree ring road like most major cities have.

Until that time the South Ring road will continue to be a car park.

EnzoScifo

oh and any new crossing at dunkettle would definitely be tolled!

TheSunIsShining

https://www.boards.ie/discussion/comment/123750243#Comment_123750243

Totally agree. And pushing ahead with Limerick Road without dealing with what happens to traffic that wants to access the South Ring is just plain stupid. They need to start the North Ring once and for all and start with the Limerick Road being linked to the Dublin Road.

As an aside - what does the JLT close so often for maintenance? I've never seen anything like it for any other tunnel. There's clearly an issue with it I assume?

Chris_5339762

There is absolutely no point adding capacity to the tunnel unless the south ring is widened all the way to the Kinsale Road junction, where it become three lane anyway. Otherwise you'll just end up with a bottleneck somewhere along its length.

Tunnel jamups will become small fry when the M28 opens anyway - because the jamups westbound at the N40/M28 junction going over the Douglas Flyover will dwarf them.

The North Ring is desperately needed - in any case the M8/M20 section. But you need an alternative to the South Ring.

The Cork Luas should help with this as the onward connectivity would encourage people out of cars (me for instance). But that is just glacial.

AugustusMinimus

https://www.boards.ie/discussion/comment/123748511#Comment_123748511

The original proposal was for 1 lane in each direction.

eastie17

people complain about drivers being the problem, and there’s a bit of that but surely best practice engineering would have built it based on anticipated behaviour by drivers from research/experience? I mean even basics like not having a major exit to your capital city in the right hand lane. The number of people who don’t seem to realise that for whatever reason and suddenly try to manoeuvre over indicates a bad design.

Yeah sure people are idiots whatever, but good design takes muppetry into account. This didn’t

AugustusMinimus

https://www.boards.ie/discussion/comment/123751529#Comment_123751529

How would you have designed the junction without having a right exit to Dublin. The design team did their best given spacial constraints.

The issue is more a lack of signage and driver awareness.

niloc1951

https://www.boards.ie/discussion/comment/123751592#Comment_123751592

N8 sign is as it should be, 'USE LEFT LANE' would be a useful addition. The M8 sign is misleading; it should be like the N8 sign with 'USE RIGHT LANE' included

https://maps.app.goo.gl/ZiCtFDgWxCyC4EKt7