Motorway/ road classed other on the same road!

mysterious

Ok, Due to so many repacked NDP and hiccups along the road....

What Kind of roads is been planned for the Inter Urban routes?
Dublin to the regional cities I.e. Cork, Limerick, Galway & Waterford.
Why can't they have a decent motorway from start to finish between Dublin onto Cork and Limerick?
By European standards its relatively short distance:rolleyes:
Its only a matter of time before these dual carriageways will be outdated, for example N7 Nenagh Bypass!
Not only that these roads, will have different speeds and designs from constant new bits of road been built here and there or alternatively changing from high class motorway to so called super dual carriageways to normal dual lane road and so on... anyone think this is a bit f**** up, excuse my French. It’s such a waste. Why can't they just build it one type and get it done, its 10 years waiting for these super classed roads to come on now and there are still miles behind other EU countries in terms of our road infrastructure

Limerick to Nenagh was to be a Motorway, what happened here
The same with most sections of the N8 etc,

Cork to Limerick N20 was to be a dual road from Rathduff to Croom, now appears to be dead in the sand, or supposedly new two plus on type roads

Port tunnel etc.

would'nt be great if we could drive from one major city to another without hitting red lights...:)

mike65

You can almost drive from Waterford to Cork without stopping at lights. There's a full set in Castlemartyr and pedestrian lights on the Dungarvan relief road and at Killeagh.

Mike.

Slice

What's the difference between a motorway and a 'high-quality dual carraigeway'?

seamus

Calling it a "High-quality dual carraigeway" allows them to set high speed limits, but also leaves the door open for doing dumb things like putting in traffic lights and junctions.

Andrew Duffy

High-quality dual carriageways have the same design characteristics as motorways, and thus cannot have at grade junctions. Councils can apply a 120km/h speed limit to any dual carriageway, and since most of the new ones are designed for that speed it's highly likely. The only difference between a motorway and a high-quality dual carriageway is the traffic restriction; tractors and agricultural machinery can use a dual carraigeway but not a motorway.

loyatemu

tractors and agricultural machinery can use a dual carraigeway but not a motorway.

I think this is the pertinent point - its to appease farmers, they can use the new road to move equipment around, they can also have access gates opening directly onto the new road.

None of this is particularly safe, neither is the fact that cyclists, pedestrians, hitchhikers, people on mopeds etc can use the road and mix with traffic going at 100+ km/h.

In france they have a classification of road that is a notch below a motorway but is still restricted to fast moving motor traffic (indicated by a picture of a car on a blue background).

jlang

loyatemu wrote:

tractors and agricultural machinery can use a dual carraigeway but not a motorway.

I think this is the pertinent point - its to appease farmers, they can use the new road to move equipment around, they can also have access gates opening directly onto the new road.

I don't think they can actually. There are access roads and underpasses for connecting farmhouses to existing roads and farms to other parts of farms on the other side of the road. As was said, the design is the same as for a motorway, it's just that there's no alternative route so they can't ban these vehicles, L-drivers, bicycles, etc.

spacetweek

Andrew Duffy wrote:

High-quality dual carriageways have the same design characteristics as motorways, and thus cannot have at grade junctions. Councils can apply a 120km/h speed limit to any dual carriageway, and since most of the new ones are designed for that speed it's highly likely. The only difference between a motorway and a high-quality dual carriageway is the traffic restriction; tractors and agricultural machinery can use a dual carraigeway but not a motorway.

There's a bit more to it than that. The median and lanes are narrower, particularly the stopping lanes, and the junctions have tighter entry and exit lanes. All of this saves land and therefore money. HQDCs are appropriate for many of the routes in Ireland, because the traffic predictions probably don't justify motorways the whole way. The only problem is that they are hard to widen if you run out of capacity, because the median is too narrow to add lanes to, so you have to start widening into the neighbouring fields which is messy and expensive. Maybe it would have been better to just go with motorways the whole way?

mackerski

spacetweek wrote:

There's a bit more to it than that. The median and lanes are narrower, particularly the stopping lanes, and the junctions have tighter entry and exit lanes.

None of this is set in stone. Many Hi-duals (Arklow) have long ramps and pleny of median. Similarly, motorway stretches may compromise on some of these nice-to-haves. Doesn't the soon-to-open stretch of M4 have a reduced median? Granted, we have very little in the way of tight loops on ramps and the only ones I can think of are on on-ramps, where the danger isn't as great. Expect this to change a bit once the M50 junction upgrades come onstream, ISTR a few tight paths in there.

Dermot

murphaph

According to the NRA design manual (on their site somewhere-I can't be bothered looking for it) a high quality dual carriageway is exactly the same as a motorway in terms of design and build-it's just the restrictions aren't placed on it so tractors etc. can use it. It is in no way inferior in it's sight lines etc. to a motorway. The N11 has bits of HQD2 and ordinary D2.

Maskhadov

so all our dual carriage way is really motorway bar the farmers driving their tractors on them ? thats great news

murphaph

Maskhadov wrote:

so all our dual carriage way is really motorway bar the farmers driving their tractors on them ?

No. There's loads of regular D2AP (dual, 2 lanes either side, all purpose, ie. not restricted like a motorway) about, some with grade separated junctions however, but still below motorway design specs so not classed as motorway. To be honest, the farmers won't cause too much bother at all and it appears they will have to pay tolls on the N6 etc. so that'll discourage them.

Victor

Andrew Duffy wrote:

High-quality dual carriageways have the same design characteristics as motorways, and thus cannot have at grade junctions.

No, the NRA have specifily reserved the right to roundabouts, traffic lights, farm access, etc.

jlang wrote:

I don't think they can actually. There are access roads and underpasses for connecting farmhouses to existing roads and farms to other parts of farms on the other side of the road.

While ideally there would be cattle underpasses everywhere, it may be uneconomic in places.

HQDC won't have hard shoulders or proper medians - merely 1m wide "hard strips"

murphaph

Victor wrote:

No, the NRA have specifily reserved the right to roundabouts, traffic lights, farm access, etc.

..

HQDC won't have hard shoulders or proper medians - merely 1m wide "hard strips"

As far as I can see from reading the NRA design manual for regional design offices to follow (mostly copied from the UK one) the HQDC is to be built exactly the same as motorway. This is from that NRA manual;

8.7A High Quality Dual Carriageway –
Category 5C (Table 4): This is the highest
category of all-purpose road. All geometric
design standards shall be in accordance with the
requirements of NRA TD 9 and TD 22 for
motorways. In order to obtain a smooth flowing
alignment, the principles stated in Paragraphs 8.7
and 8.9 shall be followed. High Quality Dual
Carriageway is only to be used where agreed with
the National Roads Authority.

NRA TD 9 is the booklet that contains all the geometric specs for all road types, so that paragraph is stating that HQDC is to be built as if it were a motorway, ie, no at grade junctions or traffic lights etc.

Andrew Duffy

^ What he said ^

The design manual is here:

http://www.nra.ie/News/DownloadableDocumentation/htmltext,1795,en.html

The National Road Needs study describes the various types of road and levels of service:

http://www.nra.ie/PublicationsResources/DownloadableDocumentation/GeneralPublications/file,595,en.PDF