The Sandyknowes roundabout on the M2 is one of the busiest and most notorious junctions in Northern Ireland. The roundabout not only connects two motorways (the M2 and the A8(M) to Larne harbour) but also local accesses to Glengormley, Mossley and Hightown and the huge industrial estate at Mallusk. Despite the addition of four sets of traffic lights, widening to three lanes and the introduction of spiral lane markings, traffic still grinds to a halt here twice a day.

This scheme, first proposed in the consultation document "Expanding the Strategic Road Improvement Programme" in July 2006, will see the junction improved to provide better access between the A8(M) and M2, which represents the strategic non-local movement.

Options

The form that this improvement will take is unclear, but the price estimate of £10m suggests that at least some thought has been given to it. The only description of the scheme (from 2006) is very vague: "Improvement to link the A8 Larne to the M2 motorway without being delayed at the Sandyknowes roundabout". Two types of improvement are possible:

• A conservative approach would be the construction of a pair of dedicated link roads between the M2 south-facing sliproads and the A8(M) across the centre of the roundabout. This would entail a third bridge under the M2 and a reconstruction of the roundabout with new traffic lights. A similar scheme was undertaken on the Sydenham Bypass at Knocknagoney to replace the former roundabout. Traffic would still have to stop at lights, but the movements would be more direct.

• A more radical approach would be to construct two flyovers or underpasses to connect the A8(M) directly to the M2 citybound. This would be more expensive, visually intrusive and involve much more land but would allow free flow movements between the two motorways.

The existance of a separate proposal (see link at top of page) to construct a "relief" junction for Sandyknowes (but beyond 2015) may influence the decision on the design of this scheme. Construction was anticipated to be between 2013 and 2018 at the time of writing (May 2008).

Updates

6 March 2010: I was speaking recently to a member of Roads Service's strategic road improvement team. They noted that since the completion of the M2 widening scheme (j4 Sandyknowes to j2 Greencastle), and the signalisation and lane improvements at Sandyknowes, the congestion here as been significant reduced. They went on to note that this means that there may now be less of a case for constructing a direct link between the M2 and the A8(M) than was anticipated when this plan was announced in 2006. Only time will tell.

Photos

Aerial photo of Sandyknowes Roundabout with the M2 running left-right and the A8(M) to the top left. Belfast is to the right. [Roads Service]

Sandyknowes Roundabout seen looking from the A8(M), showing the part time traffic lights which were made permanent early in 2008. [Wesley Johnston]