M11/N11 - M50 (J4) to Coyne's Cross (J14) [options published]

prunudo wrote: »

First time seeing that purple route. The level of detail on the red route would lead me to think thats the one they're going for, although maybe reading too much into it. Must ask the parents if they've received anything official from arup recently.

Few interesting additions including jn7 link roads. Interesting alignment at jn9 too, possibly for future northern access route to Greystones. Also a link road at jn11 linking Kilquade road to Farrenkelly rd.

I raised the is red the preferred route because of level of info/detail question in previous discussions with ARUP, and they said that because there is already a road on the ground they are inevitably significantly more informed about what is likely and what is not if they chose that route. They said not to read too much into the level of detail they have with red. Kind of makes sense when you think about it.

I'm currently thinking they are leaning towards cyan route because of the sudden introduction of the tunnel option. This clearly seems like a red herring, it wont be the preferred route, and has been introduced at a late stage in order to justify the preferred route.

If preferred route was red yes they'd have to show that they have considered all possible alternative options in order to justify going through the Glen SAC. But surely if the tunnel is there to tick the all other boxes for the Habitats Directive, they'd have done more public consultations on it and at least appeared to be more thorough etc? If they go red it is inevitable it will end up in court challenged because it is in contravention of European law, so they would need to have crossed every T and dotted every I to defend that challenge.

Which leads me to think it is there to justify the cyan route. If they go for that, there will be a huge uproar about cost, "awful waste of money, when you could have just widened the existing road, we don't need a new motorway", they can say look widening the N11 through the Glen is not an option, and the only other feasible option is a tunnel, and that is three times the cost or whatever.

Possibly overthinking this I admit, but have had plenty of time on my hands!

prunudo wrote: »

Personally think, for longevity and future proofing, the cyan route or similar is a better route than what the red route has become.
But, that ship has sailed, its 40 years too late, I think the current cyan route will meet a lot of local opposition, but then the red route will meet outside opposition and more likely to end up in the courts. Its going to be a conundrum for the designers, thats for sure.

Agree on the cyan route, it's a far better long term solution.

They'll meet opposition whichever way they go.

Cyan opposition will be largely disgruntled locals bearing the brunt of the CPOs. Their case will be principally property rights etc.

Red opposition will have a stronger case, be better funded, better organised with a larger reach.

I think they'll have a far harder job overcoming the opposition to the red route.

prunudo wrote: »

Not sure why a parallel link road isn't or hasn't been looked at in the past.
I believe a flyover at the old Drummin junction is planned to connect Willow and Delgany. That would allow Barry's bridge to become one way and return to being used as an on ramp. ( is my mind getting fuzzy or was it origanlly one way, can't remember).

Loyatemu's suggestion looks like a neater job than a flyover to achieve the same thing.

prunudo wrote: »

I agree, just not sure why they've really explored this option.
Parallel link roads would solve a lot of the congestion issues at peak times. There are far too many local traffic movements interacting with mainline traffic which in turns contributes to the stop start nature of traffic flow.
Netwown/Kilpedder/Willow grove residents going to Greystones/Delgany (Jn12-jn10). Roundwood/Kilmacanogue residents going to Bray (jn8 -jn 7) and Enniskerry residents goings Bray also (20 bends to jn6).
Also people turning off to Enniskerry, going from mainline or from jn7 are at odds with movements of traffic joining mainline from jn7.
When you actually sit down and think about it the whole section of road is a shambles. Doesnt know whether its a main interurban or a local road.

Yep totally agree with all of the above which is why I think the best solution is focus turning that stretch of N11 into a road that serves the local traffic and go with the cyan for interurban traffic.

It just seems so obvious. I'm not sure the cost would be much higher either by the time you mess about with flyovers and parallel link roads to try and solve both problems.

prunudo wrote: »

If I have this right, the purpose of this upgrade is to add a 3rd lane, whether that be a bus lane or for general traffic. I can't think of anywhere where we current have a 3 lane tunnel. Port tunnel, Limerick, Jack Lynch all 2 lanes. Even tunnels I remember from the UK are only 2 lane. From a safety point of view, would a 3 lane tunnel be problematic. Just wonder is this tunnel idea really a runner at all.
I'd prefer they put a tbm under Bray head to increase the train capacity if they're going to all that trouble tbh.

The purpose of the upgrade is to improve safety and reduce congestion - whether that is best achieved by adding a third lane, a bus lane, closing junctions, new offline motorway section or something else is what ARUP are currently in process of deciding.

This is why I am skeptical they will make significant improvements north and south of the Glen, and leave the SAC section as is. I think that would be very hard to argue that they have achieved the objective of the scheme given the Glen is biggest cause of collisions and congestion.

A two lane tunnel can achieve this objective if it is free flowing.