The planned tunnel under the Shannon may have its proposed operational height raised to 4.9 metres along with the Dublin Port Tunnel in a recognition of the fact that so-called "supertrucks" are likely to become more common.
The Minister for Transport, Mr Brennan, is to receive the final version of a consultant's report on the matter in two weeks. The report is expected to say that an increase in the height of the Dublin Port Tunnel would cost between €20 and €30 million and could add just two months to the planned completion date in early 2005.
Mr Brennan visited the site of the proposed Shannon tunnel yesterday. His spokesman said that the tunnel was still at the planning stage, so a decision to increased its planned height could be made if required without any delay to the project.
Such an increase seems likely following the apparent acceptance by the Minister that larger trucks requiring extra clearance will become more common on Irish roads. This follows a report earlier this year from the National Institute of Transport Logistics suggesting that the trend in Britain was towards larger trucks.
This represents a turnaround from the position adopted by the Minister last April when he said: "There is no need to interfere with the height of the tunnel in any way."
His spokesman said the following month: "The Minister is not making any apologies. He doesn't think Ireland wants these supertrucks."
In the same month the Dublin city manager, Mr John Fitzgerald, wrote in this newspaper: "We don't believe the 'raise the height' argument stands up to the most basic cost-benefit analysis."
However, the Minister appointed independent consultants to examine the issue in September after persistent campaigning by groups representing the main users of Dublin Port.
Yesterday the Transport Umbrella Group, representing business users of Dublin Port, including the ferry companies and the Irish Road Haulage Association, said it would welcome the proposed increase. The group's chairman, Mr Jerry Kiersey, said the maximum truck height on ferries was five metres, meaning "an extra nine inches would be enough for us".
Ireland has no maximum vehicle heights, but there is a four-metre maximum in many European countries. The British government, however, favours trucks of over five metres in some circumstances.
Dublin City Council insists the original plan was devised according to Austrian standards, considered to be the optimum, and that only Spain and parts of Britain catered for taller trucks. Work began on the 4.5km tunnel in June 2001.
The Fine Gael spokesman on transport, Mr Denis Naughten TD, yesterday welcomed the expected decision to accommodate larger trucks. He questioned the cost estimate of €20 and €30 million, saying estimates from others had predicted a cost in excess of €100 million.