A Tunnel is to be built under the River Shannon at Limerick in a public-private partnership to create a new gateway to the west by 2006.
Consultants engaged by the local authorities in the region and the National Roads Authority (NRA), decided on a toll tunnel in preference to a low-level opening bridge following a three-month consultation period.
It will be the third tunnel for road traffic in the State following the completion of the Dublin Port Tunnel, but it will be more similar in scale to the Jack Lynch Tunnel in Cork.
The second phase of the Southern Ring Road project will cost up to £240 million, with the tunnel costing about £75 million of that.
Dublin, Cork and Waterford traffic will pay a toll of about £1 to use the tunnel, bypassing Limerick city before joining the existing N18 near Cratloe in Co Clare.
The tolls would not be prohibitive, and would be similar to the M50 in Dublin, Mr John Flemming, of the NRA, said. The tendering process is expected to begin in January.
The project was a vital element in completing the national road network at Limerick, Mr Gerry Grant, of MC O'Sullivan consultants, said yesterday.
An estimated 30,000 vehicles currently using the Thomondgate, Sarsfield and Shannon bridges will be taken out of the city's daily traffic.
The major disadvantage to building a low-level opening bridge was traffic disruption and the impediment it would cause to ships going to Limerick Docks.
Shannon Foynes Port Company backed the tunnel option which will cost about 7 per cent more than the bridge over its lifespan.
"The port of Limerick is a major constraint. It receives about 200 ships a year, and that is expected to grow. That had to be allowed for," Mr Grant said. The tunnel will have no visual impact, will be open continuously and will cause no disruption to shipping or road traffic flows.
The consultants also decided in favour of a `western option' route which will run to the west of Coonagh village, close to the Shannon bank, for a two-mile stretch.
A causeway will have to be built across Bunlicky Lake as part of the development.
The tunnel will go to 15 metres under the Shannon and will incorporate a dual-carriageway roadway with an emergency walkway in between.
Mr Grant said up to 400,000 tonnes of silt would have to be removed from the river bed.
"However, once constructed and in place, its environmental impact is very minor indeed," he said.
City manager Mr Brendan Keating said the tunnel was a significant piece of infrastructure for the midwest.