Over 1,000 construction jobs will be created in the next two years as part of a major upgrade of the N11 and N7 road networks.
BAM Contractors today signed a public-private partnership contract worth €282m with the National Roads Authority on behalf of the Department of Transport.
The project will see BAM design and build a new freeflow junction at Newlands Cross on the N7 and carry out several works on the N11.
There will not be any tolls on the new sections of road that they are constructing.
As part of the deal signed, they will be responsible for the operation and maintenance of the road sections for 25 years.
The new junction at Newlands Cross will enable motorists to drive from the south to the north of the country without hitting any traffic lights.
The works on the N11 include the construction of a 16km dual carriageway linking the end of the Arklow bypass with the end of the Ashford bypass, as well as two new interchanges at the Beehive junction and at Jack White's crossroads.
A service area will also be built at Ballyellin on the Gorey bypass.
Construction on the projects is expected to begin in May.
The N11 works will be completed within 28 months and it is planned that the new section of the N7 will be completed within 21 months.
Minister for Public Expenditure and Reform Brendan Howlin said the European Investment Bank will provide around €70m for the projects.
AA Ireland's Director of Consumer Affairs Conor Faughnan has welcomed the announcement of the new projects.
Speaking on RTÉ's News at One, Mr Faughnan said there should be no major disruption to traffic flow during the construction of the freeflow junction as a clause in the contract states that three flowing lanes must be maintained in both directions at all times.
"At long last we're starting to have a continuous, connected modern motorway network," he said.
Mr Faughnan said that while the infrastructure is expensive, we have never built a piece of infrastructure that we regretted.