N2 - Slane Bypass [planning granted]

Amtmann

Slane bypass balloon test details revealed

RICHARD McCULLEN

DETAILS OF the balloon tests to be carried out as part of the public hearing into the proposed new Slane bypass and bridge were given yesterday before the proceedings were adjourned.

The oral hearing has adjourned until March 29th to allow Meath County Council to carry out a balloon test at the site of the proposed new bridge to evaluate the visual impact of the structure on the surrounding area, including Brú na Bóinne.

The council hopes to conduct the test next Friday and Saturday, weather permitting.

Two blimp-type balloons will be positioned on each bank of the Boyne at Fennor, the site of the proposed bridge, about one mile east of the existing Slane bridge.

The balloons will be set at two possible bridge heights – the preferred 18m above ground level and a lower 12m option.

The test for the preferred 18m option will take place between 10am and 1.30pm each day when the balloons will have red banners attached, while the test for the 12m option will take place between 2pm and 5pm each day when the balloons will support blue banners. Each balloon is approximately 6.1m long and 3.7m high while the banners are 3.7m long and 1.2m high.

When the oral hearing resumes at the end of the month supporters and critics of the proposed bridge will have an opportunity to give their reaction to the tests.

The proposed N2 Slane bypass and bridge will see traffic divert from the existing bridge and road because the new dual carriageway will allow vehicles travel faster and safer, design engineer Séamus MacGearailt told An Bord Pleanála’s oral hearing yesterday.

Mr MacGearailt was responding to questions from barrister Colm MacEochaidh, senior counsel for former attorney general John Rogers who is opposed to the new dual carriageway, which includes provision for a new Boyne bridge.

http://www.irishtimes.com/newspaper/ireland/2011/0305/1224291373701.html

veryangryman

@Poster who said that this DC should not be built:

You say that this is only 3.5KM. Yet you also state that this magically will mean that the rest of the N2 is going to be upgraded.

Get real - look at Dromod/Roosky N4 bypasses. Theyve been around years and yet there is no real sign of the Mullingar-Longford gap being plugged nor the road to Sligo/Collooney being upgraded.

How about this. If hypothetically, the NRA made a promise that no other sections are going to be upgraded, would you settle allow for the bypass being built? Yes as a DC - we want to discourage traffic from going through town. The better the road, the less that will be daft enough to go through town

SeanW

Chris_5339762 wrote: »

The N2 should be de-trunked and the M2 section reverted to R status with a 100kmh speed limit. Funnelling a motorway into Slane is wrong and sends out the wrong message about the type of road it is.

Ok, building a Motorway standard road and then slapping HQDC regulations on it is a proven mistake, both from a planning (one off houses) and speed limits (obvious temptation to break them) perspective. That's why there were 2 rounds of HQDC>Motorway reclassification already. The Dublin-Ashbourne motorway isn't going anywhere.

Secondly, under Irish law, a road doesn't necessarily have to be a National road to carry a Motorway section. You could in theory have a Motorway section of Regional road, so if you de-trunked the N2 South of Ardee, you would have (for example) the R222 Dublin-Ardee with an M section, M222 between the M50 and Ashbourne.

IMO the Slane bypass should only be S2 and shouldnt be designed for 100kmh running so curvature and gradients wouldnt be as much of an issue.

If the only reason is to save money, perhaps. But there's a danger of getting too cheap with a bypass, like Enfield's pre-Motorway inner bypass, which is so irrelevant by virtue of it's longer length, ridiculously low speed limit, extra roundabout etc that a lot of traffic dodging the M4 toll goes through the town.

From what I understand there's little danger of that happening to Slane, but I think as a general rule, bypasses should be as fast as is practical.

And heres a thought. Why does Slane always attract problems for its gradients in/around the town when the N25 at the pike near Dungarvan is just as steep?

The N25 is a Euroroute which has been identified as needing some dual carriageway treatment, all somehow connected with the Atlantic Road Corridor plan.

L1011

Chris_5339762 wrote: »

Yeah S2 is just a standard 2 lane road.

Not to question the engineer, but the NRA have said that it costs 10% more to build Type 2 DC (4 lane carriageway) over Type 3 (2+1, 2 lanes in one direction, one in the other). So 8% to go from S2 to Type 2 DC just doesnt add up

Meath Co Co have a VERY wide standard for S2 for national primaries and associated routes. Take a look at the Dunboyne Bypass (which is an R road) for instance.

Pete_Cavan

veryangryman wrote: »

@Poster who said that this DC should not be built:

I presume you are referring to me.

veryangryman wrote: »

You say that this is only 3.5KM. Yet you also state that this magically will mean that the rest of the N2 is going to be upgraded.

Having a DC bypass of Slane, 100kph S2 to Ashbourne and motorway from Ashbourne to Dublin will make the N2 a very attractive route for traffic coming from Monaghan, north Louth and Northern Ireland. Why pay to use the M1 when you can use the N2 for free (exit M1 at junc 12)? The extra traffic on the N2 will mean it will lead to calls for Ashbourne - Slane to be upgraded to DC and for Collon to be beypassed. This would be a complete waste of money as the road is running with 10km of, and parallel to, an existing motorway.

veryangryman wrote: »

Get real - look at Dromod/Roosky N4 bypasses. Theyve been around years and yet there is no real sign of the Mullingar-Longford gap being plugged nor the road to Sligo/Collooney being upgraded.

Completely irrelevant.

veryangryman wrote: »

How about this. If hypothetically, the NRA made a promise that no other sections are going to be upgraded, would you settle allow for the bypass being built? Yes as a DC - we want to discourage traffic from going through town. The better the road, the less that will be daft enough to go through town

A S2 bypass discourages traffic from going through town equally as well as a DC. The main objectives of the bypass are to provide another bridge over the Boyne and to remove traffic from the town of Slane - S2 bypass would do this.

veryangryman

Pete_Cavan wrote: »

Completely irrelevant.

Elaborate much?

Your saying that the rest of the road will be upgraded and im giving you an example where it doesnt happen that way - please give a counter argument and ill take it on its merits.

Pete_Cavan

veryangryman wrote: »

Elaborate much?

Your saying that the rest of the road will be upgraded and im giving you an example where it doesnt happen that way - please give a counter argument and ill take it on its merits.

The intention is to upgrade the N4, they just havent got round to doing all of it yet.

veryangryman

Pete_Cavan wrote: »

The intention is to upgrade the N4, they just havent got round to doing all of it yet.

By that logic, you would also take the fact that the "intention" was already to upgrade the rest of the N2, am i right? Check NRA site for the original plans for this.

The bypass taken on its own merit, should be built. Nobody will allow the rest of the route to be upgraded - not a fear of it. 3.5KM of a road built to save countless lives will not magically drive on the rest of this N2.

FWIW i do agree (as ive mentioned before) with long distance Dub-Derrry traffic using M1 to Dunleer/Ardee. Slane still needs a bypass though. Dualling it will not encourage toll dodging to any great extent. Timewise it will not make that much difference for the 3.5KM.

People who want to dodge a toll will always dodge it. Those who pay it already will continue to do so because their time spent on the road for such a long journey is more important that the €1.90. Ergo, the Slane bypass will not influence ones decision.

Pete_Cavan

veryangryman wrote: »

By that logic, you would also take the fact that the "intention" was already to upgrade the rest of the N2, am i right? Check NRA site for the original plans for this.

The bypass taken on its own merit, should be built. Nobody will allow the rest of the route to be upgraded - not a fear of it. 3.5KM of a road built to save countless lives will not magically drive on the rest of this N2.

FWIW i do agree (as ive mentioned before) with long distance Dub-Derrry traffic using M1 to Dunleer/Ardee. Slane still needs a bypass though. Dualling it will not encourage toll dodging to any great extent. Timewise it will not make that much difference for the 3.5KM.

People who want to dodge a toll will always dodge it. Those who pay it already will continue to do so because their time spent on the road for such a long journey is more important that the €1.90. Ergo, the Slane bypass will not influence ones decision.

If the choice is between

a) pay for to use the motorway

or

b) get off the motorway, take a DC bypass of Slane, using the the relatively straight N2 between Slane and Ashbourne which has plenty of opportunities for overtaking (mainly between Balrath and Ashbourne) and then motorway from Ashbourne to Dublin for free

most Irish drivers would take option b).

L1011

Pete_Cavan wrote: »

If the choice is between

a) pay for to use the motorway

or

b) get off the motorway, take a DC bypass of Slane, using the the relatively straight N2 between Slane and Ashbourne which has plenty of opportunities for overtaking (mainly between Balrath and Ashbourne) and then motorway from Ashbourne to Dublin for free

most Irish drivers would take option b).

You seem to think that the N2 is sitting beside the M1.

The M1 toll is cheap, as they go. Most Irish drivers will continue on it rather than use the N51 to get there to "save" 1.90 (likely to be 1.80 soon) in fuel they'll probably lose on the extra drive.

You have very, very odd ideas about the average long-distance Irish driver. Methinks you're not one.

veryangryman

I dont agree that people will all of a sudden want to add at least half hour onto their journey to save the measly sum of €1.90 - most people driving this route are not from Cavan

Sorry couldnt resist

But well have to agree to disagree.

Slane Resident

If only 15% (or 16%) of traffic using the N2 now could possibly go on the M1, why do you think that just because there's a 3.5 km stretch there's suddenly going to be mass migration from the M1 over? I'm not in any way familiar with roads, I point my car and go, but I am familiar with the Slane issue and that just doesn't make sense to me.

SeanW

point of reference: Most people who toll dodge on the M1 go through Drogheda town. Regarding Dublin-Belfast, Slane is irrelevant.

Pete_Cavan

More examples of posters on this forum favouring a needlessly over-spec'd road just for the sake of seeing more roads built, without applying common sense.

There is absolutely no logic in building 3.5km of DC when the road for 25km either side of that DC is S2 - unless of course the plan is to eventually upgrade the entire route to DC. This would be ridiculous because it would be an outrageous waste of money to build a DC shadowing an existing motorway (the N2 between Slane and Ardee is within 10km of the M1 so it is "sitting beside the M1").

The main objectives of the bypass are to provide another bridge crossing and to remove traffic from the village of Slane, an S2 bypass achieves these objectives equally as welll as a DC bypass. The only thing a DC bypass offers above this is a higher build cost. I thought we wanted to remove the dangers of the existing bridge and relieve Slane village, not create the best served transport corridor on the planet - 3 DC/motorways sitting within 16 miles (M3 at Navan, Slane bypass, M1 at Drogheda) and all in a sparsely populated, low density region. The Celtic Tiger is well and truly gone, in case you havent noticed.

Anyway, there is no chance of the ~€50bn being made available for a DC bypass any time soon so if the NRA had any sense they would reduce it to S2 which would be better value for money and have some hope of getting the bypass built in the next 5-10 years. Had they been more reasonable and gone for an S2 bypass from the start it may have progressed a lot quickly, instead they gave Vinnie and the crusties ammunition to kick up a storm with their hysterical cries of "dont build a motorway through Bru na Boinne".

veryangryman

Pete_Cavan wrote: »

The main objectives of the bypass are to provide another bridge crossing and to remove traffic from the village of Slane, an S2 bypass achieves these objectives equally as welll as a DC bypass. The only thing a DC bypass offers above this is a higher build cost. I thought we wanted to remove the dangers of the existing bridge and relieve Slane village, not create the best served transport corridor on the planet - 3 DC/motorways sitting within 16 miles (M3 at Navan, Slane bypass, M1 at Drogheda) and all in a sparsely populated, low density region. The Celtic Tiger is well and truly gone, in case you havent noticed.

Anyway, there is no chance of the ~€50bn being made available for a DC bypass any time soon so if the NRA had any sense they would reduce it to S2 which would be better value for money and have some hope of getting the bypass built in the next 5-10 years. Had they been more reasonable and gone for an S2 bypass from the start it may have progressed a lot quickly, instead they gave Vinnie and the crusties ammunition to kick up a storm with their hysterical cries of "dont build a motorway through Bru na Boinne".

Value for money? At 8% odd extra, you get a dual carriageway. Seriously think of the big picture please. The same way you get better value when buying in bulk at the supermarket, this road will be a much better proposition for money. May even generate employment/tourism in the region.

Also, 10KM is not nextdoor. Visit your "nextdoor" neighbour who is that far away for a cup of tea. Take the bike sure, its not that far at all. For all your posts, the fact remains that a shedload of trucks DO use Slane bridge for better or worse and this situation needs changing

Slane Resident

Pete - it's a 3.5 km stretch of road, not a dual carrigeway from Dublin to the North! You're complaining about Vinnie but you're rehashing most of his arguments. I know you're not in the pro-Vinnie camp but you're falling into the mistake, I believe, of listening to his arguments which have already been dismissed at the hearing as being an "interesting side issue".

3.5 kilometres, to take heavy traffic out of Slane. 16% of traffic are long distance so a proportion of them may well be toll dodgers who are avoiding the M1, but another proportion will be people for whom the N2 makes more sense than the M1 destination-wise.

8% extra to build a four lane road which will mean safer overtaking opportunities and which will provide a leeway for increased traffic into the future (unlike the M50). If they didn't do that, in ten years time there'd be uproar over their lack of foresight.

As for the "three motorways within Meath" argument, the engineer at the hearing stated that this argument he finds particularly annoying, and I agree with him. Meath is one of the larger counties, and it's closest to Dublin. Of course you're going to have motorways going through it before they branch out elsewhere - they have to. That doesn't mean that all 3 go to the same destination and are interchangeable.

1600 trucks a day will be taken out of Slane village, off Slane Bridge, by a 3.5 km stretch of road which will be built for 46 million, and the NRA have said that all road spending now will be focusing on safety and the Slane project is right up there. We've listened to the arguments against it, and we've listened to the rebuttal of those arguments. Sorry Pete, but you're just wrong. It makes sense, it will save lives, there's no alternative, and it has to go ahead.

Sponge Bob

The proposed bypass is an S2 road not a Dual Carriageway , what is this overspec crap...it is rightspec not overspec ????

Pete_Cavan

veryangryman wrote: »

Value for money? At 8% odd extra, you get a dual carriageway. Seriously think of the big picture please. The same way you get better value when buying in bulk at the supermarket, this road will be a much better proposition for money. May even generate employment/tourism in the region.

The NRA say the cost difference between Type 2 DC and Type 3 DC is 10%. As S2 has one less lane then Type 3 DC, it is reasonable to assume the cost difference between S2 and Type 2 DC would be closer to 20%. It is nothing like buying in bulk at the supermarket, a large proportion of the cost of the road is made up of labour and plant costs which are determined by the length of time they are needed, so the shorter the construction time the lower the costs, no economy of scale.

veryangryman wrote: »

Also, 10KM is not nextdoor. Visit your "nextdoor" neighbour who is that far away for a cup of tea. Take the bike sure, its not that far at all.

If you have a motorway 10km away, you do not need a DC running parallel to the motorway.

veryangryman wrote: »

For all your posts, the fact remains that a shedload of trucks DO use Slane bridge for better or worse and this situation needs changing

For all your posts, the fact remains that a S2 bypass and bridge would be equally as effective at taking a shedload of trucks out of Slane as a DC bpass would. The safety aspect of the bypass comes from avoiding the existing bridge and the approach to it, which again S2 does as well as DC. Give me one good reason why we should spend extra money building a DC bypass when a S2 bypass does the same job for less money.

veryangryman

Pete_Cavan wrote: »

Give me one good reason why we should spend extra money building a DC bypass when a S2 bypass does the same job for less money.

Safety. Feel free to counter argue that and get one person who backs you up.

SeanW

Pete_Cavan wrote: »

The NRA say the cost difference between Type 2 DC and Type 3 DC is 10%. As S2 has one less lane then Type 3 DC, it is reasonable to assume the cost difference between S2 and Type 2 DC would be closer to 20%.

WRONG. A 2+1 has no hard shoulders, whereas an S2 does. The cost of building a 2+1 over an S2 is therefore negligable, as the difference in width is negligable if there even is one. So your (counter)argument is back to square one.

If you have a motorway 10km away, you do not need a DC running parallel to the motorway.

You do if traffic levels warrant it. Also, as I said before, there is a need to avoid under-specing the bypass so that it doesn't become irrelevant as the old Enfield Bypass on what is now the R148 has become.

If you have a motorway 10km away, you do not need a DC running parallel to the motorway.

You do if traffic levels (for whatever reason) warrant it.

Give me one good reason why we should spend extra money building a DC bypass when a S2 bypass does the same job for less money.

Dual carriageways are safer. The cost differential between S2 and 2+2DC is marginal. The only reason not be use 2+2 is either an extreme need for cost savings, or as you have displayed, opposition on some questionable point of principle.

Pete_Cavan

SeanW wrote: »

WRONG. A 2+1 has no hard shoulders, whereas an S2 does. The cost of building a 2+1 over an S2 is therefore negligable, as the difference in width is negligable if there even is one. So your (counter)argument is back to square one.

Reduced S2 has a pavement width of 8m, standard S2 12.5m and Type 3 DC 13m. Reduced S2 is good enough for the Slane bypass because most of the road either side of the bypass is of that standard anyway. So your (counter)argument is back to square one.

SeanW wrote: »

You do if traffic levels warrant it. Also, as I said before, there is a need to avoid under-specing the bypass so that it doesn't become irrelevant as the old Enfield Bypass on what is now the R148 has become.

That would suggest you are also in favour of upgrading the entire N2 to DC, or at least from Ashbourne to Slane. How can you not see the madness of building a DC parallel to, and within 10km of, an existing motorway which has already cost the taxpayer over a billion euro. Now you want to replicate it! So we need two motorways and a DC within a 16 mile corridor. It is this idea of retaining and upgrading all national primary routes and shadowing the existing roads that has seen us waste hundreds of millions of euro building over spec'd roads to serve every one horse town in the country. We would have saved a fortune and have a complete motorway network now if we redrew the national primaries. The idea that Slane needs a DC bypass because it is a national primary route is ridiculous.

SeanW wrote: »

You do if traffic levels (for whatever reason) warrant it.

As has been pointed out, 86% of the traffic on the N2 between Ashbourne and Collon is local traffic and therefore the road should be detrunked as it is not of national importance. There is not going to be an explosion in population in Ashbourne or Collon any time soon so reduced S2 is good enough.

SeanW wrote: »

Dual carriageways are safer. The cost differential between S2 and 2+2DC is marginal. The only reason not be use 2+2 is either an extreme need for cost savings, or as you have displayed, opposition on some questionable point of principle.

The arguments about DC being safer are irrelevant as the DC section is only 3.5km long and you will have 20km of S2 at either end of the bypass. Again you are back to upgrading the entire N2 if you want to make the road safer (and by which logic every road we build should be at least DC). The issue here with regard to safety is the steep descent on approach to the existing bridge. S2 bypass provides another bridge so problem solved, no need to go to DC.

Slane Resident

So to save 8% of the cost, you should build a road that is less safe, just because there's poor road on either side of it?

Sorry, but that doesn't make sense to me. You build whatever you're building now, to the safest standard you can. You can't change the entire road network but you can make sure that anything built from now on is safe as possible.

SeanW

Pete_Cavan wrote: »

Reduced S2 has a pavement width of 8m, standard S2 12.5m and Type 3 DC 13m. Reduced S2 is good enough for the Slane bypass because most of the road either side of the bypass is of that standard anyway. So your (counter)argument is back to square one.

You would only use Reduced S2 if the road was to carry a small amount of traffic and if the whole N2 South of Ardee were due to be imminently detrunked. Neither, to my knowledge, is on the table. So we're back to Standard S2 vs. 2+2DC.

That would suggest you are also in favour of upgrading the entire N2 to DC, or at least from Ashbourne to Slane.

I am NOT in favour of this (though I have no objection in principle) provided that a case can be made for it. I.E. traffic levels would have to make that case, by exceeding best practice for a single carriageway.

How can you not see the madness of building a DC parallel to, and within 10km of, an existing motorway which has already cost the taxpayer over a billion euro. Now you want to replicate it! So we need two motorways and a DC within a 16 mile corridor.

To be clear, I'm only in favour of building the Slane Bypass as DC for the moment.

Without evidence of further need for DC treatment on the N2, the only thing I would do with it would be to provide a Grade Separated Junction at the Northern end of the M2, so that N2-Dublin traffic wouldn't have to bother with that roundabout.

As has been pointed out, 86% of the traffic on the N2 between Ashbourne and Collon is local traffic and therefore the road should be detrunked as it is not of national importance.

However the road remains of significant importance if it is heavily used.

The arguments about DC being safer are irrelevant as the DC section is only 3.5km long and you will have 20km of S2 at either end of the bypass.

You couldn't be more wrong - with 20 km of S2 at each end a 3.5km section of 2+2 would give anyone stuck behind a slowpoke a chance to overtake in comfort and safety. It was in the "post IMF road design standards" thread that we should consider intermixing sections of 2+2 with mainlines of S2.

Again you are back to upgrading the entire N2 if you want to make the road safer (and by which logic every road we build should be at least DC). The issue here with regard to safety is the steep descent on approach to the existing bridge. S2 bypass provides another bridge so problem solved, no need to go to DC.

I'm in favour of building bypasses to good specifications so that it's use becomes a no-brainer for through traffic. I am simply sounding a note of caution that cheaping it out might lead to an Enfield Mark II, where the R148 (old N4) bypass is actually slower than going through the town. Your plan risks doing precisely that, for at least some traffic.

I believe that bypasses should be built to a convincing standard. What happens to the rest of the road is irrelevant.

lucernarian

The plan for Slane shouldn't lead to an Enfield type situation because the old bridge route is so cumbersome. As the bridge is one-way and is likely to stay like this, there are lengthy waits at the traffic lights. Then there's another set of traffic lights at the main crossroads which will give the N51 priority if the bypass is built.

Sponge Bob

It should be built as an S2. The whole idea is to take the traffic off a really old bridge in a village that can't handle traffic.

Even if the new S2 ends up congested at times then so what...it is safe and congested where the old bridge is dangerous and congested.

The N2 should not get any more DC other than the bit it has aound Ashbourne.

L1011

Pete_Cavan wrote: »

Reduced S2 has a pavement width of 8m, standard S2 12.5m and Type 3 DC 13m. Reduced S2 is good enough for the Slane bypass because most of the road either side of the bypass is of that standard anyway. So your (counter)argument is back to square one.

The traffic figures are too high to build RS2.

Pete_Cavan wrote: »

As has been pointed out, 86% of the traffic on the N2 between Ashbourne and Collon is local traffic and therefore the road should be detrunked as it is not of national importance. There is not going to be an explosion in population in Ashbourne or Collon any time soon so reduced S2 is good enough.

If you're going to use the fact that most of the traffic is local and hence not toll dodging to support your argument at one point, you need to drop the arguments that are destroyed by it - such as the toll-dodging one.

Pete_Cavan

MYOB wrote: »

The traffic figures are too high to build RS2.

Most of the rest of the N2 between Ashbourne and Collon is RS2 and there are no major issues with capacity. If the Slane bypass should be DC then logically the rest of the N2 between Ashbourne and Slane should also be upgraded to DC - this would be a spectacular waste of money. N2 Slane Bypass Environmental Impact Statement - Non-Technical Summary says;

The proposed bypass is forecast to carry a design year traffic flow of between approximately 10,000 and 12,300 AADT in 2027.

So building the Bypass as Type 2 DC is providing capacity for almost double the estimated traffic in 2027!:eek: This is the definition of over specified. The estimated traffic is within the range for S2.

The same report also lists the objectives of the bypass as;

• To improve traffic safety by removing through traffic from the existing route through Slane Village and over Slane Bridge
• To improve the environment of Slane Village by removing a significant portion of north/south through traffic
• To obtain an improved level of service suitable for a National Primary route
• To achieve an objective of the Meath County Development Plan 2007 – 2013

All of which are met by an S2 bypass. S2 is good enough for a road that should not even be a national primary route.

Cool Mo D

I agree with the above. Slane desperately needs a bypass, but a single carriageway is plenty. A single carriageway is perfectly capable of handling over 15,000 vehicles per day.

L1011

Pete_Cavan wrote: »

Most of the rest of the N2 between Ashbourne and Collon is RS2 and there are no major issues with capacity. If the Slane bypass should be DC then logically the rest of the N2 between Ashbourne and Slane should also be upgraded to DC - this would be a spectacular waste of money. N2 Slane Bypass Environmental Impact Statement - Non-Technical Summary says;

You build roads to the capacity, not the same as adjoining roads. By that utterly ridiculous idea the N8 to Cork would have been S2 the entire way, because the adjoining roads for each scheme were...

Also, the bypass needs guaranteed overtaking opportunities as it is removing one set each way - the passing lane northbound and the fact that cars get to pass trucks through the bridge control system.

SeanW

Pete_Cavan wrote: »

If the Slane bypass should be DC then logically the rest of the N2 between Ashbourne and Slane should also be upgraded to DC - this would be a spectacular waste of money.

I challenged you on this point specifically so I'll repost what I posted before

SeanW wrote:

I'm in favour of building bypasses to good specifications so that it's use becomes a no-brainer for through traffic. I am simply sounding a note of caution that cheaping it out might lead to an Enfield Mark II, where the R148 (old N4) bypass is actually slower than going through the town. Your plan risks doing precisely that, for at least some traffic.

I believe that bypasses should be built to a convincing standard. What happens to the rest of the road is irrelevant.

To re-iterate: if a bypass is built to a convincing standard, what happens to the rest of the road is irrelevant.

Indeed it has been suggested by some, for example in the "Post IMF road design standards" thread, that mixing 2+2 and S2 would be a good idea, and I think that arrangement would work for the N2 in that area.

All of which are met by an S2 bypass. S2 is good enough for a road that should not even be a national primary route.

But you only want it done to an RS2 standard (like Enfield!) you were crystal clear on that point - S2 was total overkill, according to you. So we're back to comparing S2, which is only 0.5m narrower than Type 3 dual (2+1) and only about 10% cheaper than 2+2.