The €170 million Ballincollig bypass was officially opened today by the Transport Minister, Séamus Brennan.
The project, which is six months ahead of schedule, is being opened in two phases with the 8km from Ballincollig to Ovens open to the public from today.
The remaining 3.5km will be opened by the end of December.
The bypass was built by a Turkish consortium, Gama Tubin and its 300 strong Turkish workforce, and will mean a saving of 30 minutes on journeys at peak time on the Cork to Killarney road.
