Work to start on Belfast-Londonderry A6 road
Major construction work on the main road between Belfast and Londonderry is due to begin within weeks.
Only minor work will take place along a contested section of the route near the home of Seamus Heaney, which is set to face a further legal challenge.
The development of a stretch of the A6 at Toomebridge was the subject of an unsuccessful court case over concerns about its environmental impact.
The £160m road was a flagship project for the former NI Executive.
Work will begin on sections between Randalstown and Toomebridge and from Moyola to the Castledawson roundabout.
The A6 Hillhead Road in Toomebridge will be closed from 20:00 BST on Friday until 18:00 BST on Saturday for work on a 350m-stretch from Blackpark Road to the Creagh roundabout.
Environmentalist Chris Murphy lost a court case challenging part of the route around Toomebridge on the basis that a proper assessment had not been completed in to its impact on protected swans.
The part of the route he challenged runs close to the key wetland of Lough Beg, which has internationally protected status.
Mr Murphy plans to lodge an appeal next week.
The authorities have said the project will reduce peak journey times by a quarter and improve safety on a busy road used by 18,000 vehicles a day.
They hope the entire scheme will be substantially complete in early 2021, with the Randalstown to Toomebridge section open to traffic by 2019.
The Department of Infrastructure said it had met all of its environmental commitments to ensure no adverse impact on protected flowers or animals, including the whooper swans.
It said that along the contested section of route only "essential work involving alterations to utility supplies, minor archaeology/geotechnical testing and ground preparation to the south of the existing bypass will be completed at this time".
It added that it would work to conclude any further legal challenges as soon as possible.