Submitted by BU’s ABC Source
First let me clarify a simple point. The structures now being called flyovers are more correctly termed overpass bridges.
The analysis carried out by 3S and presented to Government (both administrations) used the Norman Niles roundabout as the test junction. The analysis showed that the “flyover” solution would have alleviated the congestion along the highway. It did however show that even with the “flyovers” gridlock would still exist in the east-west, that is, into Bridgetown. The analysis had some errors that should be pointed out. These are (1) the analysis did not take into consideration that the traffic crossing any one roundabout in the north-south direction traversed several roundabouts while almost all the traffic in the east-west direction crossed only one roundabout. This tended to give a much higher count and therefore weight to the north-south traffic. (2) the economic analysis that showed the flyover solution to be cost effective assumed a similar economic value to traffic in all directions. We all know that delays to traffic into Bridgetown on mornings have a significantly greater economic impact than traffic in any other direction. (3) at the time the analysis was done the stated cost of the flyovers was considerably less than August 2007 when a revised cost was given. This could have had a considerable impact on the cost-benefit analysis.
The type of construction for the flyovers is also to be questioned. The flyovers were to have been constructed of structural steel (Structural Steel Solutions Ltd.). In view of our poor track record on maintenance in Barbados several Engineers felt that this was not the preferred solution. A pre-stressed concrete solution would have been preferable since maintenance would be considerably less and the cost may have been lower given the rapid increases in the cost of steel. In addition, there has been a similar structure constructed in the recent past in Barbados. I refer to the Lancaster bridge which was designed in Barbados by Barbadian Engineers, erected by a Barbadian contractor and the pre-stressed beams were made in Trinidad, our Caricom neighbour. In fact, construction of the Lancaster bridge was a far more difficult undertaking than any flyover on the highway would have been since the central pier for the Lancaster bridge was in the bottom of a 60 feet deep gully while all the piers for the flyovers would have been at road level.
Rethinking the flyovers was therefore prudent. Whether or not they are revisited in the future the design (and designers) should be seriously reconsidered and our considerable local expertise employed.
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