Details of the fourth River Shannon crossing at Limerick in the form of either a tunnel or a bridge will be put on public display for consultation purposes from today.
The £200 million project, the largest of its type in the midwest, involves the construction of a dual carriageway around the south of the city. It will take traffic from Dublin, Cork and Waterford, bound for Ennis or Shannon Airport. Up to 40,000 vehicles will be removed from the main traffic routes going through Limerick, which cross the river on the Shannon, Sarsfield and Thomond bridges.
Drivers will be charged a toll, the first outside Dublin, under the public-private partnership project. "The scheme will have to be subsidised to some extent to make sure the tolls are reasonable," Mr Pat O'Neill, the project engineer, said.
A tunnel under the Shannon or a low-level opening bridge are the favoured options for phase two of the Southern Ring Road project, to be constructed by 2006. Currently on the Shannon, there is a swing bridge at Portumna and an opening bridge at Roosky, Co Roscommon.
"The tunnel would cost in the order of £70 to £75 million. A low-level opening bridge would be in the order of £60 million," Mr O'Neill added.
A tunnel would have a "neutral visual impact", according to the consultants, MC O'Sullivan and COWI of Denmark, and it would have no impact on shipping.
Limerick port lies above the proposed crossing points which are within 200 yards of each other under the two western and eastern options. "The preferred route options on view were chosen with communities, existing constraints and maximum road usage in mind," Mr Alan Lord, project manager for the consultants, said.
A low-level opening bridge, similar to the East Link bridge in Dublin, could disrupt traffic due to mechanical failure, the consultants noted, but it would have less environmental impact on the river during construction. There would be potential for extra traffic with hard shoulders and potential for pedestrian and cyclist use. However, traffic delays would occur when the bridge is open and there would be an ongoing risk of ship collisions.
Views from the public will be considered and an oral hearing will be held if written objections are made to An Bord Pleanala.