N8/N25/N40 - Dunkettle Interchange [under construction]

AugustusMinimus

hans aus dtschl wrote: »

That makes sense. The problem is that this traffic is currently rat-running and will continue to do so to avoid the future upgraded interchange. The spend might not occur at the interchange itself, maybe instead there will be traffic calming measures on the R639.
But they'll need to do something, because I know of lots of "Fermoy" origin users who are currently opting to rat-run and that won't change.

That’s very different though. All mainline users have to pay €1.90.

This will only affect M8 South to N8 West users. And at that I don’t think it will result in any significant tailbacks as

1. The majority of M8 south traffic continues through the tunnel.
2. This movement will have priority at all roundabouts it must go through.

hans aus dtschl

AugustusMinimus wrote: »

That’s very different though. All mainline users have to pay €1.90.

This will only affect M8 South to N8 West users. And at that I don’t think it will result in any significant tailbacks as

1. The majority of M8 south traffic continues through the tunnel.
2. This movement will have priority at all roundabouts it must go through.

I think we might be at cross-purposes. I've attached an image so we're on the same page: this is the movement I suspect will continue to rat-run to Tivoli and the Northside.

This movement will has priority at all roundabouts except one (green in my attachment) and I don't see that roundabout being a major issue.

The problem I'm predicting is at the blue circle on my attachment. This is the merge between Tunnel-to-LittleIsland and Dublin-to-N8 traffic. That's a join between a light flow (we both agree) and a very heavy flow.

The problem is that anything exiting Little Island West via this new interchange has priority over this traffic flow so I expect tailbacks on that slip-ramp during the AM peak due to accordion effect if nothing else. I'm expecting that the added time induced by this slowdown and the Dunkettle roundabout signalisation will keep users off the M8 and keep them firmly on the R639.

All mainline users don't pay, you can join the M8 South at Watergrasshill for free. This was an effort to avoid this problem. You might remember they had to include traffic lights and junction changes in Watergrasshill because so much traffic continued through to use the R639?

It's also free to join the M8 South at Glanmire but this is never used. Instead this exit sees a steady exodus OFF the M8 during the AM peak. Even more surprisingly, the Watergrasshill exit also sees a steady exodus of cars to join the R639 and rat-run to avoid Dunkettle.

I know double-digit numbers of people who exit the R639 daily to rat-run instead, to Hollyhill, Tivoli and Little Island. And I suspect the new arrangement will be no more attractive to them.

I'll hold my hands up and say I could be totally wrong here, and that there will be no tailbacks at the point in blue on my attachment. And also that the Dunkettle Roundabout signalisation won't induce further delay to this movement such that it's unattractive. I hope I am wrong, in fact.

What I do know is that the current high-speed rat-running in the Glanmire/Upper Glanmire/Rathcooney/Watergrasshill areas is a reasonably serious issue.

AAAAAAAAA

hans aus dtschl wrote: »

A reasonable question/statement but you might be surprised at the cycle traffic levels. Per annum, it's around 85% leisure, around 1500 people, around 5,000 trips. Obviously a lot less than motorised transport, but they do exist. Can't give you the source for the data I'm afraid.

I have no doubt that some people do it (as they do it everywhere), but without some kind of segregated cycle route along the N8 it will never see any sort of widespread use. Right now, the plan is effectively a dead end as no one but the most determined cyclists would dare to compete with the 100kmh traffic after the Dunkettle Roundabout.

hans aus dtschl

AAAAAAAAA wrote: »

I have no doubt that some people do it (as they do it everywhere), but without some kind of segregated cycle route along the N8 it will never see any sort of widespread use. Right now, the plan is effectively a dead end as no one but the most determined cyclists would dare to compete with the 100kmh traffic after the Dunkettle Roundabout.

Yes I think I understand where you're coming from now and agree that Dunkettle's a serious problem area for sustainable transport. Most people I know wouldn't want to attempt to cycle or walk there.

There's quite a big area there that's virtually "car only" with houses and employment on all sides of it. And the solutions aren't hugely complex or expensive, they're simply being ignored.

spacetweek

Truckermal wrote: »

Slightly OT but still relevant but why have they stopped cutting the Grass on the approach from Dublin? It looks like your entering Beirut as opposed to a modern European city!

<off-topic>This is often done on purpose these days to provide habitat for bees.</off-topic>

yannakis

Are these works part of the general interchange upgrade?

https://twitter.com/dunkettleint/status/1303316797899313154

Chris_5339762

They are part of the advance works contract, not the main contract.

The main contract isn't signed yet (but hopefully will be soon).

The Cork - M8 slip was easy to build, and I suspect will be used for nighttime closures of the interchange. Whilst it will only marginally reduce traffic on the roundabout, it may result in a slight rejigging of the lights.

mydiscworld

Nice video. So you tapke the new left slip road for M8, yeidling to traffic on the right that have come through the tunnel.

Where's the new right slip road heading?

grogi

Chris_5339762 wrote: »

They are part of the advance works contract, not the main contract.

The main contract isn't signed yet (but hopefully will be soon).

The Cork - M8 slip was easy to build, and I suspect will be used for nighttime closures of the interchange. Whilst it will only marginally reduce traffic on the roundabout, it may result in a slight rejigging of the lights.

Not only that. Once the Dunkettle RB has running lights, the traffic coming from the East going North, will cross the construction site not leaving the flyover, turn around at the RB and use that slip.

AugustusMinimus

mydiscworld wrote: »

Nice video. So you tapke the new left slip road for M8, yeidling to traffic on the right that have come through the tunnel.

Where's the new right slip road heading?

Under the M8 and onto a new roundabout Outside the Ibis Hotel onto the old N25. Bridge will need to be constructed.

hans aus dtschl

grogi wrote: »

Not only that. Once the Dunkettle RB has running lights, the traffic coming from the East going North, will cross the construction site not leaving the flyover, turn around at the RB and use that slip.

Very nice. I didn't realise this: a clever little change.

AugustusMinimus wrote: »

Under the M8 and onto a new roundabout Outside the Ibis Hotel onto the old N25. Bridge will need to be constructed.

Yes, exactly. This is the one I keep banging on about as a better route as a good cycle/pedestrian routing.

AugustusMinimus

hans aus dtschl wrote: »

Very nice. I didn't realise this: a clever little change.


Yes, exactly. This is the one I keep banging on about as a better route as a good cycle/pedestrian routing.

To do that you’ll need to have cycle traffic go across a lane of cars. They’ve taken the easier option which requires maybe an additional 200m of cycling.

hans aus dtschl

AugustusMinimus wrote: »

To do that you’ll need to have cycle traffic go across a lane of cars. They’ve taken the easier option which requires maybe an additional 200m of cycling.

Under the slip lane would have made more sense.

You're making little of the proposed route's inadequacies.
It has an additional hill built in, 3 road crossings with no priority, and without splitting hairs, it'll be around 300m to 350m extra. No big deal whatsoever if you've a motor, but not ideal if you're walking or cycling.
Every design manual that exists says don't give cyclists/pedestrians extra gradients, extra distance, extra stops, extra conflicts with motorised traffic.

This one's like a checklist of things you shouldn't do, if you were remotely serious about sustainable travel.

Pete_Cavan

hans aus dtschl wrote: »

Under the slip lane would have made more sense.

You're making little of the proposed route's inadequacies.
It has an additional hill built in, 3 road crossings with no priority, and without splitting hairs, it'll be around 300m to 350m extra. No big deal whatsoever if you've a motor, but not ideal if you're walking or cycling.
Every design manual that exists says don't give cyclists/pedestrians extra gradients, extra distance, extra stops, extra conflicts with motorised traffic.

This one's like a checklist of things you shouldn't do, if you were remotely serious about sustainable travel.

Would the cycle lane have to go under one or both new lanes? Getting under the lane immediately next to it could be possible as that lane is rising to meet the M8. The next lane (closest to the rail tracks) seems to be a good bit lower as it have to go under the M8 meaning a very steep drop would be required to get under it and provide sufficient headspace.

hans aus dtschl

Pete_Cavan wrote: »

Would the cycle lane have to go under one or both new lanes? Getting under the lane immediately next to it could be possible as that lane is rising to meet the M8. The next lane (closest to the rail tracks) seems to be a good bit lower as it have to go under the M8 meaning a very steep drop would be required to get under it and provide sufficient headspace.

Yes exactly it would only need to go under the furthest West/North slip lane. That's the one that rises up to meet the M8 as you say. Effectively run the pedestrian/cycle route beside the railway tracks.

I don't know their reasons for deciding against it, but I hope they had a reason other than "cost". You'd have been talking small investment at build stage to have quite a desirable route for all users, whereas I'd describe the proposed route as a deterrent to both novice and very competent users (no mean feat making things worse than they are!). Perhaps that slip lane just doesn't rise enough? I don't know I'm afraid.

Pete_Cavan

hans aus dtschl wrote: »

Yes exactly it would only need to go under the furthest West/North slip lane. That's the one that rises up to meet the M8 as you say. Effectively run the pedestrian/cycle route beside the railway tracks.

But the pedestrian/cycle route wouldn't be directly beside the railway tracks would it, there would be another traffic lane in between (i.e. the lane I said you wouldn't be able to get under)? Just clarifying.

a/tel

Took a few shots at the end of the pedestrian/cycleway today. Looks more or less complete.

AugustusMinimus

hans aus dtschl wrote: »

Under the slip lane would have made more sense.

You're making little of the proposed route's inadequacies.
It has an additional hill built in, 3 road crossings with no priority, and without splitting hairs, it'll be around 300m to 350m extra. No big deal whatsoever if you've a motor, but not ideal if you're walking or cycling.
Every design manual that exists says don't give cyclists/pedestrians extra gradients, extra distance, extra stops, extra conflicts with motorised traffic.

This one's like a checklist of things you shouldn't do, if you were remotely serious about sustainable travel.

Just saw the last posters photos of the end of the cycle route. Didn’t realise what a roundabout route they’ve taken.

Presumed they would have hugged the M8 but no.

a/tel

AugustusMinimus wrote: »

Just saw the last posters photos of the end of the cycle route. Didn’t realise what a roundabout route they’ve taken.

Presumed they would have hugged the M8 but no.

Behind the wall pictured pictured is the literally the M8.

There is nowhere to go due to the bridge unless they has built steps down to Richmond Hill just before the bridge. The road is so narrow there its just too dangerous.

But there will have to be some sort of footpath from Richmond Hill down past the Gaelscoil to meet the new footpaths leading towards Burys Bridge

spacetweek

What is that road in the second picture? Looks like a new build but coulnd't possibly be as there are no footpaths or bike lanes.

hans aus dtschl

AugustusMinimus wrote: »

Just saw the last posters photos of the end of the cycle route. Didn’t realise what a roundabout route they’ve taken.

Presumed they would have hugged the M8 but no.

Yep, and my apologies, I'm obviously not describing the issues with this route very well.
Experienced users will avoid it because of the loss of priority (I'm confident they'll cycle on the slip ramp). Novice users will avoid the area because it's "too dangerous".
Unfortunately it's my belief that a good solution was cheaply available.

a/tel wrote: »

There is nowhere to go due to the bridge unless they has built steps down to Richmond Hill just before the bridge. The road is so narrow there its just too dangerous.

But there will have to be some sort of footpath from Richmond Hill down past the Gaelscoil to meet the new footpaths leading towards Burys Bridge

There is a proposal to add a cycle lane and footpath (segregated) on the North side of the L2998 (Richmond Hill) under the M8 bridge as part of the City Council Glanmire Part 8 schemes. I'm not sure there's enough space under the bridge, and a bigger issue is that the users will have to cross the L2998 Richmond Hill road with no controls. The LCD display there currently shows that motorists regularly do 80+ kmh, with poor sightlines.

As an experienced cyclist who cycles this area regularly, I can tell you that this is an unpleasant road to cycle. It's one of the worst parts of any journey for me, so diverting the City-to-East vulnerable traffic to here is a bad idea.

hans aus dtschl

spacetweek wrote: »

What is that road in the second picture? Looks like a new build but coulnd't possibly be as there are no footpaths or bike lanes.

This is the most northerly part of the scheme.
This view is North West from where the M8 bridge passes over the L2998/Richmond Hill.

In my scribble attached, the proposed scheme is in black, the photo location is in green and photo direction is to the North West.
The section you're seeing is the proposed shared motor/cycle/pedestrian section.

Edit:
The works are now substantially complete East of the M8.
There are no crossings of any kind at Factory Hill or North Esk. As the basic "test" goes, I probably wouldn't allow a child to traverse this scheme alone.

hans aus dtschl

Pete_Cavan wrote: »

But the pedestrian/cycle route wouldn't be directly beside the railway tracks would it, there would be another traffic lane in between (i.e. the lane I said you wouldn't be able to get under)? Just clarifying.

Sorry I just saw this message!
I think you're right, yes, it would not be directly beside the railway tracks, rather it would be beside the road which is beside the railway tracks.

marno21

Cabinet approval for main construction contract expected within weeks

https://www.echolive.ie/corknews/Cabinet-approval-for-main-Dunkettle-works-expected-81daf55d-bd20-426a-9a43-9bc7eca5b538-ds

Leonard Hofstadter

marno21 wrote: »

Cabinet approval for main construction contract expected within weeks

https://www.echolive.ie/corknews/Cabinet-approval-for-main-Dunkettle-works-expected-81daf55d-bd20-426a-9a43-9bc7eca5b538-ds

That will be fantastic news, badly needed for the city.

Pete_Cavan

marno21 wrote: »

Cabinet approval for main construction contract expected within weeks

https://www.echolive.ie/corknews/Cabinet-approval-for-main-Dunkettle-works-expected-81daf55d-bd20-426a-9a43-9bc7eca5b538-ds

Is that approval to tender the main construction contract? I thought they had issued the revised tender but the article says;

Once it is approved, we are ready, TII are ready to tender straight away.

annfield1978

Pete_Cavan wrote: »

Is that approval to tender the main construction contract? I thought they had issued the revised tender but the article says;

Tenders are back, they are ready to appoint when approval given

Chris_5339762

Yes, main construction contract. That was just poor reporting by the Echo.

Fabio

Does anyone know when the slip-road from the Glanmire Roundabout onto the M8 northbound will be open? No details in the latest Dunkettle email...

AugustusMinimus

Fabio wrote: »

Does anyone know when the slip-road from the Glanmire Roundabout onto the M8 northbound will be open? No details in the latest Dunkettle email...

Was originally supposed to be the end of September. Can’t see that happening now.