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

On #2, the correct thing to do would be to get the system to clear its learned data and start again from scratch, and learn the new environment. Right now, there is such a strong rule that says “M8 south requires greater access to tunnel in the morning” that it’s starving the other paths of access. I also have a suspicion that construction work may have removed or interfered with the queue measurement sensors/cameras, so the lights could be operating wholly on trained behaviour.

Doing that reset is outside of the power of the builders. It needs to be done by whoever works for Cork City Council to manage the traffic lights. But if the queue estimation part of the system is missing on some of the approaches, there is zero that can be done apart from manually setting weights to each approach for different times of the day.

Either way, when it comes to the lights, the ball is with Cork City Council.

(On #1 there has progress in constructing the new slip, but it’s much slower than expected, and they should have communicated better)

I also reckon the sensors are not working yep.

One thing I’ve noticed is that sequences in Dublin are longer than in Cork. In Cork you don’t get many cars through on a single sequences.

Less changes of lights reduces time wasted when no cars can go through interchanges due to safety concerns.

They are doing some work with a cherry picker on the lights at the moment, not sure what though.

My knowledge of the inner workings of traffic lights isn't great.

Tried this today, 18 mins from Carrigtwohill up through the back roads to Knockraha and on to the M8. 8 mins from getting onto the M8 to the tunnel entrance.

No traffic at all on the back roads, a small queue on the M8 where the road is reduced to one lane but got through it pretty quickly.

Only saved about five or ten mins I'd say but I'd much rather be moving than sitting in slow moving traffic!

*(Journey began at 15:38, so if I'm leaving around half 3 every evening I should be fine to go N25 to tunnel, but it's good to have another option if I have to stay later!)

The lane restriction northbound from the tunnel has been reduced by around 50÷

This weeks newsletter -

"The traffic light sequence at the Dunkettle Interchange Roundabout has been fine tuned over the last few days to best suit the new layout."

They definitely heard me bitching. To be fair it hasn't been AS bad on the N40E.

Looks like part of Link A (N40E to N25E) will open before Christmas too. More details next week but it looks for the time being that it'll be a new exit off the roundabout. That'll be great, but crash central as the lanes to get into may well change!

My previous thoughts on how link A will work temporarily before the roundabout stops being used.

My view is that the roundabout will still be used for now for the same movements. Where you exit the roundabout will change.

1. Tunnel to N25 east. The exit off the roundabout will now come before the M8 north exit. No new set of lights will be required. Previously the N25 east exit was after the M8 north exit.
2. The current exit from roundabout onto N25 east will be closed.
3. The new Tivoli to Tunnel movement will open. This slip was where the previous N25 east exit was located. This will allow the old Tivoli to roundabout slip to be closed.

At some point, the big decision to close the roundabout altogether will happen. This is the biggest cutover of the project and will require a certain number of slip roads to be open. Essentially all movements which previously involved going 90 degrees clockwise around the roundabout will need to be facilitated via slip roads before the roundabout is completely removed.

Can someone jump up on the pole and refocus the camera looking into the JLT? :-)

Thanks to whoever it was! "I can see clearly now the rain has gone" 😁

One more prediction. When the loop opens, the area boxed in red will likely be closed for traffic as no further movements will require to pass through this. It will be the first piece of the roundabout to be closed.

It will also remove the need for traffic lights releasing M8S traffic onto the roundabout.

Where will the permanent route for that movement be? Would it not still be in that area?

Also, the email states multiple links opening, will that just be the 2 obvious ones (n40n to n25e and m8s to n25e) or would it include the temporary realignment for n25w to n40s...although that's not quite a full link.

That makes sense, so it'll be more just alignment works for that link in the future so.

Huge progress, I assume it will probably be a good while until there's more to open. Mad to think this time next year it will nearly be all done