On 21 October, the Irish Minister for Transport, Martin Cullen, announced that the height of the 4.5km Dublin Port Tunnel would not be altered (T&TI, Sept 2004, p10). The decision was taken “primarily on safety grounds” said Cullen.
The minister said that cost and time delays to the opening of the project were also factors. Various options for increasing the tunnel height had been considered by the Irish National Roads Authority (NRA) and by the Nishimatsu Mowlem Irishenco (NMI) Consortium who are the contractors working on the scheme.
An independent report was commissioned with consultants Atkins in August 2003. Dublin City Council and the Irish state government also reviewed the information that included options based upon the Atkins report being priced for consideration by the NMI Consortium.
Cullen said that remedial work to increase the height of the tunnel could not be justified for several reasons. The safety considerations included reduced lane widths due to lowering the floor as part of the proposed height increase configuration. It was felt that in the context of a tunnel carrying a high percentage of heavy goods vehicles and tankers, wider lanes were a safer option with increased vehicle separation. Also, the tunnel height as constructed, is in accordance with the accommodations of existing Irish road infrastructure. Concern was expressed at possible problems on other sections of the road network arising form the tunnel discharging oversize vehicles.
The tunnel has been constructed to a height of 4.9m with an operational vehicle height limit of 4.65m. At the time of developing the scheme, the maximum height of a heavy goods vehicle on Irish roads was 4.25m. In July 2000, the legislation was revoked following a challenge by the European Commission to the procedures leading to the regulation, this left no statutory regulation governing truck heights so the NRA and Dublin Corporation decided to proceed on the basis of the already approved project.
The contractors were asked to cost the option from Atkins report of modifications that would allow trucks up to 4.9m to use the tunnel. NMI supplied two quotations to the client in May this year. Option 1 at US$82.9M and a seven month delay to the project timescale was substantially qualified, which lead to concerns that the estimate could rise. Option 2 at US$42.1M had no delay to the project timescale, but in addition to the same qualifications as option 1, it also fundamentally altered the existing contract. The Department of Transport notes the “varied manner of working” on which the lower quotation is based is not fully explained in the quotation.
In June 2004, the then Minister for Transport, Seamus Brennan, wrote to the NRA for clarification and expressed his views that safety was paramount, although he also used the notoriously vague term that the tunnel on completion has to be “fit for purpose”. With Cullen’s announcement, it seems that safety has remained the deciding factor, only time will tell if it truly is “fit for purpose”.
