An 18-mile dual carriageway from Londonderry to Dungiven was given the go ahead by the Department of Transport today.
The £400 million scheme, which will include a bypass of Dungiven, is still subject to securing future funding.
But work on the project is now expected to begin next year.
Transport Minister Michelle McIlveen said: “This announcement is very good news for the north-west and for the local economy in Northern Ireland.
“The A6 is a key transport route between Belfast and the north-west and the construction of a new dual carriageway will help to reduce journey times and improve road safety.”
“There is no doubt that this scheme represents a significant investment in our economy and will create hundreds of jobs. Businesses too will benefit from improved transport links while the public will enjoy a safer and better journey.
“The indicative allocations for the 2017/18 – 2020/21 period will fund construction of part of the A6 Londonderry to Dungiven dualling scheme.
“My Department is currently considering the extent of the scheme, including a bypass of Dungiven, that could be delivered.
“It is envisaged that priority will be given to construction from Dungiven towards Londonderry.”
The Department will now publish the formal Notice of its Intention to Proceed and the making of the Direction Order for the scheme, along with a Departmental Statement setting out its response to the recommendations in the Inspector’s report, which is now also being made available.
The public inquiries were held in September 2012 and the Inspectors reported their findings to the Department in March 2013. Following a thorough examination of the issues raised, the Department has concluded that the scheme should proceed with amendments to reflect the Inspectors’ recommendations.