Two of the State's cities are now linked by motorway for the first time, following today's opening of the final stretch of the M6 motorway by Minister for Transport Noel Dempsey.
A speed limit of 120km per hour should cut the journey east-west from the M50 junction to Galway's outer limits to two hours, according to the National Roads Authority (NRA).
Completion of the last section of the 194km route four months ahead of schedule was marked by Mr Dempsey outside Ballinasloe shortly before lunchtime.
The 56km stretch has already experienced an unofficial opening - during the recent flooding, it provided the only direct route between the east coast and Galway for almost a fortnight.
The NRA has described today's opening of the €427 million route as an "historic event", given that it is the first "major inter-urban corridor" in the Republic.
The lack of rest stops - a subject of some criticism - will be addressed, the NRA says, while a new toll booth at Cappataggle, Co Galway, will bring the total toll bill for a one-way trip to €3.80.
Galway County manager Martina Moloney has said that the route will open up Galway and the west to greater investment.
Mayor of Ballinasloe Cllr Johnny Walsh (Ind) has welcomed the fact that children and the elderly in Ballinasloe will no longer be at risk when crossing the N6 in the town.
Mr Dempsey has urged all motorists, cyclists and pedestrians to take extra precautions when travelling on our roads during the current cold snap. Met Éireann has forecast wintry showers of sleet and snow to affect parts of Ulster, Connacht, north Leinster and west Munster tonight.
"Over the coming days and into the early part of next week, showers of sleet and snow are forecast for many areas, with the northern half of the country and western counties most at risk,"the Department of Transport says.