The extra lane will be added between Naas and the M9 interchange in Kildare
Sections of the M7 motorway are to be widened to ease commuter traffic congestion, after the contract for the project was awarded.
The Naas to Limerick road will be widened from two to three lanes for approximately 14km between Junction 9 Naas North and the M7/M9 interchange at junction 11.
The contract awarded to SIAC/Colas JV also includes two additional elements: the Sallins bypass and the construction of a new interchange at Osberstown.
Work on the widening project is set to be completed by Autumn 2019.
Kildare South TD Martin Heydon explained that the €110m expansion should ease congestion on the M7, particularly during busy periods.
Deputy Heydon said: "With the M7 now carrying about 70,000 vehicles per day as the main network connection to Cork, Waterford and Limerick, commuting times for Kildare residents have increased considerably in the past year.
"Based on the award of this contract, it is anticipated that the overall project will be completed by Spring 2020 with the M7 anticipated to be completed by Autumn 2019."
A special speed limit and traffic management measures will be in place on the M7 during the construction works, although two lanes of traffic will be maintained at all times between 6am and 10pm.
Moyagh Murdock, CEO of the Road Safety Authority, welcomed the motorway expansion.
She suggested that the extra lane will improve the flow of traffic and make people less inclined to take risks on the road.