The National Roads Authority (NRA) is planning to use the State's share of future tolls on the West-Link bridge in Dublin to raise €450 million in private financing to fund the upgrade of most of the M50.
The proposal, which also includes upgrading a piece of motorway that is not even complete, is part of a two-stage plan to add an additional lane on the motorway to alleviate chronic gridlock.
The authority has been in discussions with the National Development Finance Agency about the possibility of issuing a special bond, the first of its kind, to finance the public infrastructure project.
This will also see the continued tolling of the M50 well beyond the current cut-off date of 2015, when the current tolling arrangement with National Toll Roads is due to end.
In the last six weeks the NRA has also sought expressions of interest from private firms for the second phase of the motorway upgrade.
The first phase of the upgrade, which includes upgrades of major traffic bottleneck junctions at the Red Cow Inn and Palmerstown and the addition of a third lane between both junctions, is to get under way next year. The junction linking the M50 to the M1 motorway will also be upgraded during this phase. Its €200 million cost is being met directly by the State.
A spokesman for the NRA told The Irish Times that it was hoped to finance the second phase, using the future income from the Government's share of the West-Link toll. This phase includes the addition of an extra lane between the M1 and Palmerstown junctions, and between the Red Cow Inn junction and Sandyford.
The NRA has acknowledged that this upgrade includes a section of two-lane motorway between Ballinteer and Sandyford that is not yet completed, but is due to open by Christmas. He said the upgrading of this section was unlikely to begin for a number of years.
He said the NRA "would hope to raise in the region of €450 million in financing from the future toll revenue".
He said the NRA was examining two basic options - to raise the money directly itself through issuing a bond, or for a private firm to raise the money for the upgrade itself, and to receive the Government's toll money share.
The bridge was built by National Toll Roads, which is entitled to toll the road until 2015.
Currently the State earns €8 million per year from its share of the toll, but this is expected to increase significantly as volumes on the road increase, as the State is entitled to a share of 80 per cent when car numbers rise above a certain limit.
The €450 million estimate is based on the Government's projected share of the toll to 2015 and a continuation of the toll beyond that for 10 years at the earliest.
An average of 87,000 cars per day pass over the West-Link bridge at present, and this is set to rise to 105,000 by 2008.
The N4 and N7 junctions will be upgraded to "spaghetti junction"-type roadways to enable cars to move quickly between motorways. The NRA has acknowledged the upgrade will lead to further traffic disruptions, although contractors will be required to keep two lanes open at all times.