Between Sprucefield and Carrickcarnan the road forms part of the European route E01.
The A1 is dual carriageway south from Sprucefield but some junctions remain relatively low specification as they necessitate right-turning movements across the central reservation.
[4] The scheme involving the dualling of the A1 between Beech Hill and Cloghogue was completed in July 2010, five months ahead of schedule.
[5] The Roads Service of Northern Ireland has planned to provide four further grade separated junctions.
[6] The Road Service also plan to improve the link between the M1 and A1 at Sprucefield in a scheme that would include a flyover at Hillsborough, replacing the last remaining roundabout on the route between Dublin and Belfast.