2 plus 1 road layout
Since I had just posted about the N20, I figured I should start this thread to see if there is any consensus about mapping 2 plus 1 road layouts, before I started editing the 2 plus 1 section of the N20.
2+1 is not common in Ireland, (the attached link mentions 4 sites).
It is basically an otherwise normal stretch of road with a crash barrier down the middle. The number of lanes alternates every few kilometres in either direction to give opportunity for overtaking.
Most junctions are limited, (i.e. no right turn allowed), as the barrier carries on through the junction, but some have turning lanes provided.
It is NOT a dual carriageway. Houses still have (turn-restricted) access onto the road.
The link to the Cork Roads Office is here:
http://www.corkrdo.ie/2_plus_1_road_layout.php
I would be inclined NOT to separate the road into 2 lanes, one in either direction, because there is no margin between the lanes, but the difficulty with that is that the junctions would need extra careful attention, (and would have to be locked i would think, though there is no area manager for that section of road named in the cartouche).
However, some could justifiably argue for the section of road to be mapped as 2 separate roads as you can't navigate from one direction of travel onto the other like you could on a normal road.
Has anyone any opinions?
Or experience of the other 2+1 in ireland:
Co.Cork N20 Rathduff to Mallow Retrofit 9km
Co. Leitrim N1 Dromod Roosky Green field site 8km
Co. Monaghan N2 Clontibret to Castleblayney Green field site 15km
Co. Donegal N15 Ballyboffey Stronolar Green field site 16km
or abroad?
The link mentions it is used a lot in sweden
2+1 is not common in Ireland, (the attached link mentions 4 sites).
It is basically an otherwise normal stretch of road with a crash barrier down the middle. The number of lanes alternates every few kilometres in either direction to give opportunity for overtaking.
Most junctions are limited, (i.e. no right turn allowed), as the barrier carries on through the junction, but some have turning lanes provided.
It is NOT a dual carriageway. Houses still have (turn-restricted) access onto the road.
The link to the Cork Roads Office is here:
http://www.corkrdo.ie/2_plus_1_road_layout.php
I would be inclined NOT to separate the road into 2 lanes, one in either direction, because there is no margin between the lanes, but the difficulty with that is that the junctions would need extra careful attention, (and would have to be locked i would think, though there is no area manager for that section of road named in the cartouche).
However, some could justifiably argue for the section of road to be mapped as 2 separate roads as you can't navigate from one direction of travel onto the other like you could on a normal road.
Has anyone any opinions?
Or experience of the other 2+1 in ireland:
Co.Cork N20 Rathduff to Mallow Retrofit 9km
Co. Leitrim N1 Dromod Roosky Green field site 8km
Co. Monaghan N2 Clontibret to Castleblayney Green field site 15km
Co. Donegal N15 Ballyboffey Stronolar Green field site 16km
or abroad?
The link mentions it is used a lot in sweden
Re: 2 plus 1 road layout