2 Plus 1 Road Layout: | | |
| A 2 plus 1 Road consists of two lanes in one direction of travel and one lane in the opposite direction. The two-lane section, which provides a safe overtaking zone, alternates with a one-lane section at intervals of 2km approximately. The traffic streams are separated by a safety barrier system, which prevents overtaking manoeuvres on the one-lane section. Right turning movements will be at controlled junctions and a reduction of head on collisions is anticipated.
Sweden has led the way in research and development of the 2 plus 1 road type with safety barrier systems and has constructed in excess of twenty-five such schemes since 1998, both on green field and retrofit sites.2 plus 1 roads also operate in Finland, Denmark, Scotland and Germany. The National Roads Authority in conjunction with several local authorities propose to pilot a number of 2 plus 1 schemes around the country in the near future.
At present many National Primary roads have climbing lanes with two lanes on the uphill section and one lane on the downhill section.
Irish drivers are familiar with their operation, notably the reduction from 2 lanes to 1 lane beyond the crest of a hill. Therefore the main difference between these roads and the new 2 plus 1 road type is the existence of a safety barrier between the opposing traffic streams.
Application of the 2 plus1 road by NRA:
The National Primary road network has an overall length of approximately 2800 km which carries 31% of all road traffic.The National Development Plan (2000-2006) when fully implemented will deliver approximately 1200 km of the National Primary road network to a high quality dual carriageway/motorway standard. As indicated overleaf these roads have excellent accident characteristics. The remaining 1600 km of the National Primary road network will consist of single carriageway roads.
The 2 plus 1 road type will be considered for new National Primary projects on routes to which the high quality dual carriageway/motorway standard does not apply. This applies to approximately 700km of new projects, with a potential of retrofitting an additional 150km on existing routes. Therefore this road type potentially applies to thirty per cent of National Primary roads.
Head on collisions account for 20% of accidents on two lane roads but account for 37% of fatal accidents. Single vehicle accidents account for 24% of accidents on two lane roads but account for 30% of fatal accidents.The NRA considers that the 2 plus 1 Lane Road Type with a safety barrier will significantly reduce fatal head on collisions on single carriageway roads and reduce the severity of all accidents.
In Europe there is a move towards self-regulating roads as it is recognised that the over reliance on enforcement does not ensure safe driving behaviour.The 2 plus 1 road is a step in this direction. Introduction of the 2 plus 1 road type in Ireland:
Initially there will be four pilot projects on national primary roads. These 2 plus 1 projects are as follows:
| 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 |
Publicity for this new road type:
All of the above schemes will be going through a formal planning process, which will involve significant consultation with local residents. In advance of this process, a local publicity campaign will accompany each of these pilot schemes.The National Roads Authority will co-ordinate the raising of awareness of this new road type both nationally and at a local level in consultation with the local authorities involved.
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|  | | Road safety continues to be an important issue, particularly on national primary single carriageway roads in Ireland. Any new measures that help reduce
accidents and fatalities on single carriageway roads must be further advanced. To this end, a working group comprising representatives from National Road Authority, Regional Design Offices, Local Authorities and Consultants has
been researching a new road type for the last two years.The view of the group is that the 2 plus 1 Road has potential for use in Ireland because of the poor accident record/characteristics of single carriageway roads and because of the traffic volumes on much of the National Primary network.
It is proposed to pilot four 2 plus 1 schemes around the country over the next few years. | | View Brochure |
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