The new Kilcock-Kinnegad motorway was officially opened today by Taoiseach Bertie Ahern and Minister for Transport Martin Cullen.
The 55-kilometre motorway, the longest single section of motorway in the country, was completed 10 months ahead of schedule and will be open to traffic from 2pm.
According to the Department of Transport the €600 million motorway will result in a time saving of over 20 minutes for people using the N6 and N4 Galway and Sligo roads.
Speaking at the opening ceremony, the Taoiseach said: "We have all worked to generate the resources necessary to continue to improve the lives of everybody.
"Delivery of infrastructure projects like the Kilcock-Kinnegad bypass mean road journeys can be done in less time, a major plus for communities and prosperity in the West and Midlands."
The new road features a toll plaza at Kilcock, Co Kildare, where motorists will pay an initial fee of €2.40.
However last Friday Eazy Pass Ltd, which operates the pre-paid automatic tolling systems on the M50 and the M1, told its customers that electronic tags in customers' cars would not operate the M4 toll.
The old N4 national primary route will remain open for those who do not want to pay the new tolls.
The motorway was completed by the Irish-Spanish consortium Eurolink as a public-private partnership.
Meanwhile, Fine Gael's Olivia Mitchell has criticised the Minister for not mentioning that motorist travelling from Dublin to Galway will face two tolls due to the planned toll on the stretch between Ballinasloe and Galway.
"Not only is this unfair, it is economic madness. Putting two tolls on the Dublin to Galway route is effectively dividing the country in half. If Minister Cullen was really concerned with providing a transport networl for the 21st century, he should direct the NRA to not put a second toll on the Galway route," Ms Mitchell said.
