About €282m is to be spent upgrading the N7 Newlands cross junctioninto a traffic-light-free flyover and turning the N11 between Arklow and Rathnew in Wicklow into a dual carriageway.
Transport Minister Leo Varadkar said the projects would improve safety.
“These projects will make a huge difference to road users and will finallyremove two bottlenecks which were not addressed during the boom.
“The N11 will improve safety standards the minute it’s opened, while theNewlands Cross flyover will remove the last traffic light between Cork,Limerick, and Waterford and the border.”
The deals are the first transport public private partnerships to be signedsince the onset of the recession in 2007 and 2008.
The project on the N7 — where 80,000 vehicles pass through each day — will mean drivers can go from Belfast to Cork, Limerick, and Waterford without facing a traffic light.
The flyover will replace the junction of the Naas Rd and the R113Fonthill/Belgard roads at Newlands Cross. West and southbound traffic will betaken up and over the minor road reducing the impact on local road users.
The N11 upgrade will improve safety on a notoriously dangerous stretch of road and will also include the first online service station on the route at Gorey, Co Wexford.
The carriageway will be 16.5km, connecting the Arklow bypass with the Rathnew/Ashford bypass bringing a motorway along the east coast from Dublin to Gorey.
The two road builds will run simultaneously and should be complete by the end of 2015. The projects are financed in part by Bank of Ireland and the European Investment Bank, which also signalled it will help fund the N17-18 Gort/Tuam link road and will also consider funding for the N25 New Ross bypass and the M11 Gorey/Enniscorthy roads.
Brendan Howlin, public expenditure and reform minister, said: “I am very pleased that we have achieved sign off on the latest roads project to be delivered using the public private partnership model.”