Changes in the design of the Dublin Port Tunnel should be made now to cater for taller trucks, according to Mr Eoin Ryan TD, chairman of the Oireachtas Committee on Transport.
In advance of a National Roads Authority (NRA) board meeting today at which the issue is likely to be raised, he said it would be cheaper and more practical to increase the tunnel's height while it was under construction.
"Based on what we've been told by the haulage industry, it seems to be the case that trucks are going to be larger in the future," he said. "It would be a shame if the tunnel had to be closed to make these changes."
Members of the committee visited the tunnel construction site two weeks ago and raised the issue of its height, which is set at 4.65 metres. Hauliers have argued that the height should be increased to 5.3 metres.
Representatives of the hauliers and of import and export interests, who argue that taller trucks are both operationally and environmentally preferable, have since been invited to put their case to the committee.
However, both the NRA and Dublin City Council have cited a survey of port traffic showing that only 1.8 per cent of trucks would not fit into the tunnel and said this proportion would not warrant design changes.
The Minister for Transport, Mr Brennan, was informed that increasing the height at this stage could add €100 million to the cost of the €625 million project. The NRA's position is that the height is "more than adequate".
Preliminary results of a second survey of port traffic, focusing othe south port container terminal, suggested that 3.5 per cent of ro-ro (roll-on-roll-off) traffic consists of taller trucks that would not fit into the tunnel.
But Mr Tim Brick, the deputy city engineer in charge of the project, said he had not yet seen these survey findings by the DIT's National Institute of Transport Logistics, even though they were quoted in the Sunday Business Post.
"My understanding is that the Dublin Port Company is treating these results as unvalidated," he said. Although he was aware of a trend towards taller trucks, the proportion would need to be much higher to justify changes in the tunnel's design.