The Northern Ireland government has announced its preferred route for the A8 dualling project between Ballyclare and Larne in County Antrim.
Conor Murphy, Northern Ireland transport minister, says the £113m scheme - a 14km section between Coleman's Corner roundabout and the B100 Ballyrickard Road junction - will improve road safety and reduce journey times.
About 17,000 vehicles currently use the A8 each day, a high proportion of which are HGVs travelling to and from the Port of Larne.
Work on the project is due to begin in 2013.
Tom Wilson, Freight Transport Association head of policy for Northern Ireland, says: "The A8 is an essential link connecting businesses in Ireland to large freight hubs in northern England and Scotland.
"The slow-moving, agricultural vehicles so common on this road often cause large tailbacks, 
so two lanes will certainly go some way to reducing the risk of overtaking the likes of tractors and combine harvesters."
Murphy adds: "This development, in terms of transport links, will act as a catalyst to the local economy, particularly during these uncertain financial times."