Strait of Gibraltar - Bridge or tunnel

The Gibraltar Strait is one of those remaining crossings anchored in legend for which a link has been discussed for centuries. For me, it is not a question of 'if' but of 'when' and 'how'.
A bridge crossing has been discussed several times. There is a particular article, by T.Y. Lin ("Gibraltar Straight Crossing - A challenge to bridge and structural engineers") that proposes a modified suspension bridge arrangement. This is probably the most famous scheme.



Although the article by T.Y. Lin says that the bridge is feasible with current bridge engineering knowledge and techniques, the truth is that it would be quite the undertaking, and probably not the best engineering solution.

The Spanish and Moroccan governments seem to agree with this. Following an agreement in 1979, in 1980 both governments established an agreement that saw the creation of twin organizations in Spain and Morocco to investigate the feasibility and progress in the construction of a permanent link between the two countries.

Although a bridge alternative was investigated, it was abandoned for a immersed tunnel alternative due to the following factors:

• Higher projected costs
• Technological uncertainty
• Interference with ship traffic and risk of impact
• Higher ecological impact
• Inability to phase the project in function of expected traffic increases

It seems that the project is moving forward and there are news that indicate May 2009 as the date in which a final decision will be taken about the project. If so, the tunnel construction could start in the near future.

Obviously I would prefer a bridge over a tunnel, but given the current technologies in both bridge and tunnel construction, and given the characteristics of the project, I have to agree that, at least by now, a tunnel solution seems to be the best.