N4 - Dromod/Roosky Bypass

JupiterKid · 14-12-2007 4:45am #1

The N4 Roosky-Dromod bypass was opened a few days ago. It was originally supposed to be a 2+1 road, but it was decided during constructiuon to make it a 2+2 - effectively a dual carriageway.

But surely if it was only planned to be a 2+1, the bypass must have no hard shoulders? I've heard that the divider between the carriageways is only a wire rope fence. This seems very substandard for a road that claims to function as a dualler.

Zoney · 14-12-2007 11:56am

No hard shoulders. I cannot see it being a great idea for safety, even if people stick to the 100km/h speed limit. As far as I'm concerned, the same concern applied to S2+1. Sure it makes head-on collision unlikely (unless wire barrier is left slack after previous incident) compared to wide two lane road, but it's simply introducing a new problem that breakdowns etc. are likely to result in someone getting rammed from behind. There's nowhere to pull in out of the way for any emergency. Hard shoulders aren't perfect, people have been hit in them too, but they're sure a better place to stop than the inside lane.

If hard shoulders aren't worthwhile, why do they exist at all? If they are, what does route capacity have to do with the provision of a safety feature?

munchkin_utd · 14-12-2007 12:15pm

Zoney wrote: »

..
If hard shoulders aren't worthwhile, why do they exist at all? If they are, what does route capacity have to do with the provision of a safety feature?

Why indeed!

A strip of road pavement to the same standard as the main carraigeway just in case someone has to PARK and change their tyre.

In the north for example, the hard shoulder on national roads, when it exists, are simply gravel separated fom the main carraigeway by kerbing .
Whyever we need a top notch asphalt Parking Strip (aka hard shoulder) in the republic, I will never know.

loyatemu · 14-12-2007 1:10pm

the previous road building standard of wide single carriageway was essentially creating de-facto, incredibly unsafe dual-carriageways. People regularly drive and park on the hard shoulder, cars and trucks pull into the hard shoulder to allow traffic to overtake and the overall effect is traffic weaving all over the place. You can see this on N-roads all over the country (the N25 in particular springs to mind).

For the same land-take you can mark out extra lanes and put a physical barrier down the middle - it may not be as safe as motorway but its got to be better than the free-for-all that exists on wide S2.

while the wire-rope arrangment is not great if you're a biker it does fulfill the function of stopping cars from crossing over and afaik there are no at grade right-turns on this type of road. Is there a grass or gravel verge for cars needing to pull off?

SeanW · 14-12-2007 7:09pm

loyatemu wrote: »

the previous road building standard of wide single carriageway was essentially creating de-facto, incredibly unsafe dual-carriageways. People regularly drive and park on the hard shoulder, cars and trucks pull into the hard shoulder to allow traffic to overtake and the overall effect is traffic weaving all over the place. You can see this on N-roads all over the country (the N25 in particular springs to mind).

For the same land-take you can mark out extra lanes and put a physical barrier down the middle - it may not be as safe as motorway but its got to be better than the free-for-all that exists on wide S2.

while the wire-rope arrangment is not great if you're a biker it does fulfill the function of stopping cars from crossing over and afaik there are no at grade right-turns on this type of road. Is there a grass or gravel verge for cars needing to pull off?

I couldn't disagree more - even though I've only been driving a year and a bit, I've already had my fair share of breakdowns (twice had petrol spark plugs flooded and one flat tire) and trust me, the mainline of the road is NOT a good place to be stuck when you've broken down.

I regularly see people treating long distance dual carraigeways as motorways and speeding.

As for your point about the use of hard shoulders on single carraigeways again, I disagree strongly - when a tractor or slow vehicle uses the hard shoulder, they allow you to pass them at mainline speed without having to overtake and while continuing along the course of the road.

A "kind of" dual carraigeway that will in practice be treated as a "kind of" motorway is a recipe for disaster.

murphaph · 14-12-2007 7:55pm

loyatemu wrote: »

the previous road building standard of wide single carriageway was essentially creating de-facto, incredibly unsafe dual-carriageways. People regularly drive and park on the hard shoulder, cars and trucks pull into the hard shoulder to allow traffic to overtake and the overall effect is traffic weaving all over the place. You can see this on N-roads all over the country (the N25 in particular springs to mind).

For the same land-take you can mark out extra lanes and put a physical barrier down the middle - it may not be as safe as motorway but its got to be better than the free-for-all that exists on wide S2.

while the wire-rope arrangment is not great if you're a biker it does fulfill the function of stopping cars from crossing over and afaik there are no at grade right-turns on this type of road. Is there a grass or gravel verge for cars needing to pull off?

Well I have to disagree with Sean and agree with you. The statistics in the UK show that dual carriageways without hard shoulders are very safe indeed, nearly motorway safe. Anytime you remove the possibility for head on collisions by dividing the highway you will make the road safer. I'm a biker and the wire rope is very disconcerting to ride along on a motorway, I fear it will be even more off-putting on this type of road but at least there's less chance of some goon overtaking on a blind bend and killing you outright.

As I said over on sabre-I have no problem with these roads-they are a huge improvement on WS2 (which is indeed a free-for-all and I have some pictures up on SABRE of WS2 freeforallness!) however if they only went the extra mile and used a Jersey Barrier I'd be delighted with this type of road. From the PR this road is only carrying 6,000 Vehicles per day. That is NOTHING! In the UK they wouldn't consider even dualling for that! This is a far superior road for the traffic it is carrying than you'll find across the water or over the border.

If all the planned 2+1 roads end up with this standard we will have a marvellous overall standard of national route. People have a tendency to forget that we still have some shocking cart tracks out there!

ardmacha · 14-12-2007 8:02pm

The way a road is designed, even the safety features, is related to its traffic volume. New roads are built all the time without hard shoulders and there will never come a time when all roads have hard shoulders, nor can motorways be built everywhere. There has to be a compromise. Do people prefer a wide S2 with a hard shoulder with dangerous overtaking of all sorts as well as speeding, or one of these roads where traffic going in opposite direction is segregated, but where you can only stop in lay-byes? I know which I prefer.

SeanW · 14-12-2007 11:27pm

All I know is as a motorist - if I have to break down, I'd MUCH prefer to breakdown on a single carraigeway with a hard shoulder than a half-spec motorway without.

murphaph · 14-12-2007 11:38pm

SeanW wrote: »

All I know is as a motorist - if I have to break down, I'd MUCH prefer to breakdown on a single carraigeway with a hard shoulder than a half-spec motorway without.

Are you sure? I wouldn't like to be broken down over the brow of this hill any more than if it were a dual carriageway!

The funny thing is that one might feel 'safe' in the hard shoulder. The UK (and us) have used shoulderless dual carriageways for decades and they are still much safer than single carriageway roads, even ones with hard shoulders. Most fatalities do not involve people broken down in a hard shoulder or even broken down full stop. They involve head on collisions and the like.

munchkin_utd · 15-12-2007 12:17am

Mother of moses. It really is the case that you are allowed to drive in the hard shoulder according to the rules of the road! :eek:

If a driver wants to allow a vehicle
behind them to overtake, they may
pull in to the hard shoulder briefly

http://www.rsa.ie/Home/upload/File/ROTR_2007.pdf - page 60

So in a nutshell, you DO have 2 traffic lanes going in both directions. And if thats the case making it a dual carraigeway is not a massive difference.

The only thing you'd need is some lay bys for people to pull into in case of emergency.

Chris_533976 · 15-12-2007 5:13pm

Fair enough in my book (its common sense if done safely), as long as that quote actually reads ->

If a driver wants to allow a vehicle
behind them to overtake, they may
pull in to the hard shoulder briefly
provided it is safe to do so.

SeanW · 16-12-2007 3:00am

Yep, in Murphaph's picture, the stranded motorist is safe in the hard should because they have the right of way there. If the guy driving the tractor can't see a brokedown motorist *anywhere* there, or couldn't stop in time (driving a huge vehicle at <30MPH) then he needs his eyes - or his head - examined.

The same is not true of a breakdown on the mainline of a make believe motorway where motorists have the right of way and will routinely be driving at 70+MPH

@Murphah, if I had to breakdown anywhere, the shoulders in your pic is as good a place as any.

murphaph · 16-12-2007 1:13pm

SeanW wrote: »

Yep, in Murphaph's picture, the stranded motorist is safe in the hard should because they have the right of way there. If the guy driving the tractor can't see a brokedown motorist *anywhere* there, or couldn't stop in time (driving a huge vehicle at <30MPH) then he needs his eyes - or his head - examined.

If you are a stationary vehicle due to breakdown anywhere you have a right to be there! You can't legally be rear ended on any road. That was just an example anyway-we all know cars, trucks and buses all make use of the 'hard shoulder' on irish WS2 roads and it keeps traffic moving fine and my point is that it is quite safe-there is really very little difference except that better line marking to show what's allowed and a central dividing barrier will make the 2+2 much safer than WS2. I am very confident about this and I know the statistics for fatal accidents on these roads will prove me right. They eliminate the frustration induced dangerous overtaking manouvre of the moron driving at 30mph who WON'T make temporary use of the hard shoulder on WS2.

SeanW wrote: »

The same is not true of a breakdown on the mainline of a make believe motorway where motorists have the right of way and will routinely be driving at 70+MPH

But Sean, on a motorway (in Ireland) we can reasonably expect stricken vehicles to have reached the hard shoulder. If there's no hard shoulder then we won't expect that. In any case-sightlines on motorways are long. You should easily be able to come to a comlete stop in the distance you can see to be clear even at 70mph.

SeanW wrote: »

@Murphah, if I had to breakdown anywhere, the shoulders in your pic is as good a place as any.

Agreed. As good as any but not better. That's my point-we're just removing the silly anomally of a hard shoulder which can be used as a running lane by marking it as a running lane.

Another pic....(old style german Autobahn with no shoulder)

I would at this stage like to note that Switzerland (not known for their reckless attitidude to safety) has abolished hard shoulders on some NEW MOTORWAYS, instead opting for emergency bays every kilometre or so. This is due to the ever increasing reliability of modern vehicles. Of course-in motorway tunnels very few countries carry a hard shoulder through. Switzerland is also currently removing hard shoulders on the A1 and converting them to running lanes, adding the emergency bays as they go. The swiss are actively building motorways like the above german picture.

Irish and Proud · 20-12-2007 3:17pm

Zoney wrote: »

No hard shoulders. I cannot see it being a great idea for safety, even if people stick to the 100km/h speed limit. As far as I'm concerned, the same concern applied to S2+1. Sure it makes head-on collision unlikely (unless wire barrier is left slack after previous incident) compared to wide two lane road, but it's simply introducing a new problem that breakdowns etc. are likely to result in someone getting rammed from behind. There's nowhere to pull in out of the way for any emergency. Hard shoulders aren't perfect, people have been hit in them too, but they're sure a better place to stop than the inside lane.

If hard shoulders aren't worthwhile, why do they exist at all? If they are, what does route capacity have to do with the provision of a safety feature?

The 2+2 standard consists of a 16.5m wide pavement with 4 x 3.5m lanes, 2 x 0.5m verge strips plus a 1.5m median with wire barrier. This isn't really a dual carriageway, but is a 4 lane single road with robust safety enhancements such as the barrier (stops the speeding idiots who can't drive from attempting to make the road a 3+1). Because of the relatively light traffic levels, a full DC would not be warranted and the 4 lanes (with no hard shoulder) would be enough to provide for most situations including breakdowns. These roads would generally be carrying less than 10,000 pcus per day at just 100 kph.

E92 · 20-12-2007 3:44pm

And some old style German Autobahns have no speed limit either(which makes it all the more remarkable that the Autobahns with no speed limit are no more dangerous than Autobahns with a speed limit and just shows that the slowing down mantra is really a lot of nonsense).

murphaph · 20-12-2007 7:27pm

Irish and Proud wrote: »

The 2+2 standard consists of a 16.5m wide pavement with 4 x 3.5m lanes, 2 x 0.5m verge strips plus a 1.5m median with wire barrier. This isn't really a dual carriageway, but is a 4 lane single road with robust safety enhancements such as the barrier (stops the speeding idiots who can't drive from attempting to make the road a 3+1). Because of the relatively light traffic levels, a full DC would not be warranted and the 4 lanes (with no hard shoulder) would be enough to provide for most situations including breakdowns. These roads would generally be carrying less than 10,000 pcus per day at just 100 kph.

.....and in the UK those low traffic figures wouldn't even trigger an at grade dual carriageway. They would consider S2 suitable for those traffic volumes.

SeanW · 20-12-2007 9:06pm

Yep, an S2 is what this really needed. And really, that's all it is.

It just dangerously pretends to be a "make-believe" motorway.

I had a look at the road out the train window today - it really is just a normal road with no breakdown facilites and a bit of wire rope in the middle.

The phrase "effectively a dual carraigeway" used by the OP, bears little relevance to the reality. What worries me though is the possibility that motorists will treat it as a dual carraigeway/motorway.

E92 · 20-12-2007 9:11pm

So a 2+2 is nothing like the photo of the German Autobahn we saw earlier in this thread then? Is it really the same as the part of South Ring in Cork that goes over Douglas and all there is is roadway, barrier and that's it?

Chris_533976 · 20-12-2007 9:45pm

That part of the South Ring is a mecca for stupid driving.

Victor · 20-12-2007 10:52pm

E92 wrote: »

And some old style German Autobahns have no speed limit either(which makes it all the more remarkable that the Autobahns with no speed limit are no more dangerous than Autobahns with a speed limit and just shows that the slowing down mantra is really a lot of nonsense).

I'm sorry, I really do think you are mistaken on this point, if the Germans feel a particular section of "Autobahns with no speed limit" is dangerous, they add a speed limit.

Your point is a self fulfilling delusion.

Irish and Proud · 20-12-2007 11:11pm

murphaph wrote: »

.....and in the UK those low traffic figures wouldn't even trigger an at grade dual carriageway. They would consider S2 suitable for those traffic volumes.

I don't want to be too blunt, but the UK fall way short of Irish standards when it comes to road planning - even their motorway system was done on a piecemeal basis (during the 60's and 70's) rather than the rollout method we have for the inter-urbans. Taking our small population into account, we are now more comparable to the Spanish - just look at how fast the M6 (Galway) and M8 (Cork) motorways are shaping up.

But yeah, I see your point - we'd be lucky to realise the M1 and M50 motorways under UK style planning - and that's without the M50 DPT and SEM sections - the latter required a lot of liaison with various parties in order to achieve economic viability.

Regards,

Victor · 20-12-2007 11:59pm

Actually, very long sections of motorway in the UK were built very quickly - something like 2.5 years for 60 miles of the M1.

Irish and Proud · 21-12-2007 12:16am

Victor wrote: »

Actually, very long sections of motorway in the UK were built very quickly - something like 2.5 years for 60 miles of the M1.

That's true for a number of motorway projects in the UK, but in the overall scheme of things, there seemed to be no proper co-ordination regarding the implementation of a national motorway system (Manchester, Newcastle and Glasgow still have missing links in their motorway routes to London). Also, take a look at the history section of www.cbrd.co.uk and go through the time line, then compare it to the rollout of our inter-urbans to see what I mean.

Also, remember, the UK's population is 60m - nearly 14 times that of ours - so they have far more resources at their disposal - you have to compare like with like!

Regards!

murphaph · 21-12-2007 12:21am

Irish and Proud wrote: »

I don't want to be too blunt, but the UK fall way short of Irish standards when it comes to road planning - even their motorway system was done on a piecemeal basis (during the 60's and 70's) rather than the rollout method we have for the inter-urbans.

That's incorrect. The UK developed master plans decades ago for their motorways (more precisely, their trunk roads, of which the motorways are just a part). They built bypasses and connecting straights-just like virtually everywhere, including here. That's typically how these things are done. It's much more dufficult for the UK nowadays to get anything built as GB is one of the most densely populated islands in the world and there are usually massive objections to anything that sniffs of a motorway.

Irish and Proud wrote: »

Taking our small population into account, we are now more comparable to the Spanish - just look at how fast the M6 (Galway) and M8 (Cork) motorways are shaping up.

See Victor's post above. 60 miles of M1 in a little over 2 years. We will NEVER be able to build roads that fast. Those were the days of no EIS, no public consultation, just build it.

I wouldn't say the M6 and M8 are moving quickly. They were supposed to be complete in 2006.

E92 · 21-12-2007 12:29am

UK Motorways are designed for 100 mph(160 km/h) too(I wonder are ours designed for 160 km/h?). And ALL the interurbans were supposed to be done LAST year, not 2010.

JupiterKid · 22-12-2007 5:17am

Much if not most of the UK motorway network was completed over a generation ago - about 1975 - when all this country had was the Naas Dual Carriageway, one or two other very short stretches of dual carriageways and our first motorway (Naas Bypass)) still almost a decade away.

Bear this in mind.

Victor · 23-12-2007 7:30am

http://www.nra.ie/News/PressReleases/htmltext,11151,en.html

Dr. Jimmy Devins, Minister of State at the Department of Health and Children, today officially opened the N4 Dromod Roosky Bypass. The 10km stretch of new roadway is part of pilot programme to identify the benefits of the (greenfield) 2+2 carriageway.

Delivered 5 months ahead of schedule at a cost of €84.5 million the Dromod Roosky pilot 2+2 carriageway is significant from both a safety and investment standpoint. It consists of two lanes in both directions divided by a barrier, thus limiting the risk of head on collisions. The additional cost involved, approximately 10% higher then the 2+1 road type, will deliver long term value for money through the provision for increased traffic capacity.

Commenting at the roadside, Dr. Jimmy Devins said; “This very welcome road project will provide bypasses of Dromod and Roosky villages resulting in a better and safer environment for residents. Road users will experience improved journey times and will appreciate the better driving experience the new road offers.”
Peter Malone, Chairman of the National Roads Authority said; “The opening of the Dromod to Roosky bypass serving both counties Longford and Leitrim will bring major relief to drivers travelling East, Northeast and West. It will remove two notorious bottlenecks on the N4 route resulting in an easier journey for thousands of motorists while making the area, which is a hugely popular tourist attraction, more accessible to visitors. The removal of 6,000 vehicles from Dromod and Roosky will bring with it an improved quality of life and a safer environment for residents."
The scheme has been funded by the Irish Government, under the National Development Plan 2007-2013 and part funded by the European Structural Funds. The N4 Dromod Roosky Bypass will contribute to the development of Counties Leitrim and Longford and indeed the Border, Midland and Western Region generally.

Additional notes

The Swedish Roads Authority is currently using the 2+2 carriageway road type.
2+2 carriageway road type differs from a traditional dual carriageway because it consists of at grade junctions and roundabouts.

spacetweek · 27-12-2007 3:04pm

murphaph wrote: »

That's incorrect. The UK developed master plans decades ago for their motorways (more precisely, their trunk roads, of which the motorways are just a part).

Actually, you're both right. The UK came up with a motorway development plan back in the 40s or 50s which was supposed to be complete in 20 years.

In the event, many factors came together to slow its progress, and to this day, the plan is incomplete. It's definitely true that many motorways in the UK were built in a piecemeal way, not because it was policy, but due to the blocking factors.

- Backlash against urban motorway building
- Increasingly burdensome due process
- Increasing cost
- The rise of the enviromental lobby
- High population density of England
- Regional politics, especially after devolution of Scotland

For example, due to the last point, the cross border England-Scotland M6 project will only open in 2008 - finally joining the motorway networks of England and Scotland 50-odd years after the UK started building them.

JupiterKid · 27-12-2007 9:46pm

OK to get back on topic - has anyone travelled on the Roosky-Dromod bypass yet and, if so, do they consider this new 2+2 road as safe as a conventional dual carriageway?

JupiterKid · 28-12-2007 6:41pm

And here's a photo of the Roosky-Dromod bypass.
Seems the NRA have really dropped the spec for DCs lately.:D

Duzzie · 28-12-2007 7:08pm

JupiterKid wrote: »

OK to get back on topic - has anyone travelled on the Roosky-Dromod bypass yet and, if so, do they consider this new 2+2 road as safe as a conventional dual carriageway?

The 2+2 dual carriageway (renamed a Type 2 Dual) is not intended to replace the Standard Dual (renamed a Type 1 Dual). The traffic flow threshold for a Type 2 is significantly lower than for a Type 1 and is more in line with the traffic flows on the (now deleted) Wide Single. The second lane is intended as an overtaking lane for occasional use not constant use.

As for breaking down, lengths of Type 2 between junctions is lower than on a Type 1 Dual. In most cases, a car with mechanical problems or a puncture, should be able to drive to the next junction to get off the road.

If you look at the statistics of fatal accidents in Ireland, a disproportionate number of fatal accidents are due to head-ons on single carriageways. The provision of a barrier in the central reserve greatly reduces the occurance of these head-ons, this has been proven in Sweden where 2+1 and 2+2 roads are extensively used. It should be noted that the cross section is much tighter in Sweden where no verge is provided at all.

So to answer your question, Yes the Type 2 Dual is significantly safer than the road it replaces, the Wide Single. It should not be comapred to a Standard Dual as the traffic flows are much higher on that class of road.

Duzzie

N4 - Dromod/Roosky Bypass

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