Northern Division Overtaking Opportunities
2+1 Overtaking Opportunities on Single Carriageway Roads
Overtaking is one of the most hazardous manoeuvres that drivers undertake on single carriageway roads. Platoons of traffic may form behind slower moving vehicles, leading to driver frustration and attempts at unsafe overtaking manoeuvres. Overtaking lanes provide the opportunity for platoons of vehicles to disperse over the section with the overtaking lane and provide benefits downstream of the overtaking lane as platoons take time to reform. Overtaking lanes are wide single carriageways marked out as two lanes in one direction and one lane in the other with opposing traffic streams separated by a double white line system. They provide defined overtaking opportunities to reduce traffic delays caused by slower moving vehicles. Drivers are less likely to overtake on two lane single carriageways with poor visibility when they are made aware that a safer overtaking opportunity is available ahead.
Roads Service family of 2+1 overtaking opportunities 
comprise:
- Climbing Lane where an additional lane is added to provide two lanes on steep uphill gradients.
- Differential Acceleration Lane (DAL) where an additional lane is added to provide short lengths of two lane exits from roundabouts.
- Wide Single 2+1 (WS2+1) where additional lanes are added to provide the two lanes which alternate between each direction of travel.
The Regional Strategic Transport Network Transport Plan 2015 envisaged the construction of over fifty 2+1 overtaking opportunities within the plan period. The following are some of the completed schemes.
| Northern Key Transport Corridor (location and direction of overtaking opportunity) | Completed |
|---|---|
| Glenlough North climbing lane (towards Ballymena) | April 2000 |
| Portrush Road Roundabout DALs (towards Coleraine and Ballymena) | July 2000 |
| Greenmount Roundabout DAL (towards Limavady) | April 2001 |
| Springwell climbing lane (towards Limavady) | May 2004 |
| Nutts Corner DALs (towards Antrim and to Moira) | May 2005 |
| Ballynaloob South WS 2+1 (towards Ballymoney) | March 2006 |
| North Western Key Transport Corridor (location and direction of overtaking opportunity) | Completed |
|---|---|
| Burntollet West and East climbing lanes (towards Drumahoe and Dungiven) | July 2002 |
| Glenshane North climbing lane (towards Dungiven) | July 2003 |
| Munreery climbing lane (towards Dungiven) | March 2005 |
