The Minister for Transport, Mr Brennan, has ordered an independent report on the controversial Glen o' the Downs road-widening scheme, which will now cost double its original estimate.
The 6km scheme, which has yet to be completed, is now 12 months overdue after the latest deadline of the end of August was missed. The National Roads Authority (NRA) has not received a completion date for the scheme and does not expect the road to open before the end of October.
The Department of Transport now expects the final bill to be close to €90 million. Its original estimate was €47 million. The scheme has generated 16,000 pieces of correspondence between the contractor, Ascon, and the engineers for the project. It was also due for completion by the end of last year.
Last month the Department ordered a full report from the NRA on the problems associated with the scheme.
However, as a result of the latest delay, Mr Brennan has ordered a separate independent report on how the scheme went so much over budget and time, said a spokesman for the Department.
"The Minister has been told by the NRA that an unusual set of circumstances occurred at the Glen o' the Downs that has not been replicated in other projects," he said.
"However, he has ordered a special report from an independent expert on what went wrong, and we're expecting that in the next few weeks."
The scheme, which has led to huge delays on the N11 in the last three years, has been beset by problems. It was originally planned for the early 1990s, but its design had to be drastically changed because of its impact on the Glen o' the Downs nature reserve.
Construction on the revised scheme had been due to begin in late 1997, but was blocked for nearly two years by a protest and court challenge from "eco-warriors".
It finally began construction in June 2000 and was due for completion at the end of last year. According to reports from the NRA for the Department, the delays and extra costs have been caused by a number of factors.
These include additional culverts for a river that came back to life and the installation of "ground socks" to tackle potential soil erosion problems in the glen. A marsh had to be lifted and replaced by hand.
Traffic has also been flowing through the site at a rate of 30,000 cars per day, and traffic-management measures caused further delays, according to the report. Another significant problem was the replacement of a major underground water pipe which passed through the site.
A spokesman for the Department said that contracts for roads were designed to ensure that costs and time overruns were kept to a minimum. The contractor both designs and builds the scheme, with incentives for early completion dates.