Eglinton Interchange

Eglinton Interchange is a complicated junction built as part of the Irvine bypass in 1976. The main part of the junction is a fairly standard Roundabout interchange which sits over the A78 between Irvine and Kilwinning. This connects the A78 to the A737. However, the mainline of that route crosses the A78 a short distance to the west, and so the roundabout is located on not just a spur, but a loop of the A737. From the roundabout, the northern arm curves round to the west and meets the A737 mainline at a signalised T Junction. The southern arm of the roundabout also curves west, and meets the mainline at Redburn Roundabout. It is no more than a third of a mile from signals to roundabout on the mainline of the A737, and these two interruptions question the design of the junction.

To make things even more complicated, the east facing slips onto the A78 are met midway between the dual carriageway and roundabout by the split carriageways of the B7080. As the Irvine Bypass curves southwards, the B7080 forks, with the westbound arm crossing the A78 to meet the sliproad. Traffic cannot directly join the A78, but is directed up to the roundabout, thus providing a full access connection between the two routes.

The complexity of layout described above is not, as you may suspect, a result of development of the surrounding land, as much of it is woodland. The junction was built this way to allow for a future Kilwinning Eastern bypass which was part of the original Irvine New Town Development plan and would have run directly North from the Eglinton Interchange. Indeed, when the junction was originally built, an additional exit was built on the North side of the roundabout and the original road signs were installed showing an exit to Glasgow (A736) which was patched. Under the New Town plans, bypasses would be built to the North and East of Kilwinning and would link to the A736 near Auchentiber. However, later changes to the plan emphasised the A71 to Kilmarnock and the A77/M77 route to Glasgow, and the A736 link was cancelled. Subsequent landscaping has removed the roundabout stubs and the road signs have been replaced.

History

Prior to the Irvine Bypass opening in 1976, the A78 and A737 had met at a roundabout since the Kilwinning Bypass opened in 1962. This roundabout was located roughly where the current A737 overpass is situated to the west of the modern junction. It was the eastern terminus of the dualled section of the A78, which then turned south onto its original alignment into Irvine. No trace of this junction survives today.

Routes

Route	To	Notes
A78	Prestwick Airport, Ayr
A78	Stevenston, Saltcoats, Ardrossan, Greenock
A737	Kilwinning,
A737	Ayr
B7080	Shewalton