The 8km route, which is used by 18,000 motorists daily, includes a new roundabout at the Drones Road and three flyover junctions.
Speaking at the opening ceremony, Divisional Roads manager Deidre Mackle said: “This road scheme will have a significant impact on the 18,000 motorists who use the road daily, halving journey times during peak periods, removing traffic queues, reducing driver frustration and improving safety on the route.
“The upgrade, which has retained the iconic Frosses trees, will also have knock on impacts for the local economy and contribute to wider economic development for the region both in the short and in the long term.”
Construction of the scheme by the joint venture of BAM McCann commenced in early 2015 and provided employment opportunities to seven people through the Department for Employment and Learning Steps to Work programme in addition to five student placements over 40 weeks during construction.
The project has seen around 27km of drainage pipelaid, 32km of fencing erected, 24,000tonnes of concrete poured and 280,000 tonnes of material laid in the pavement construction.
In addition, 225,000 cubic meters of peat was excavated, some of which was utilised in a local bog regeneration initiative.
“I am mindful of the inconvenience experienced by local businesses and landowners on the route during the construction phase and would wish to extend my gratitude to them for their patience,” Ms Mackle added.