One of the most difficult decisions to be made is what transport infrastructure to invest in. There are very many factors to consider, such as forecasts of future demand and external costs and benefits. All of these are difficult to value.
The solution is a full Cost-Benefit Analysis that considers all the private and external costs and values them properly. Only then can a judgement be made and even so substantial margins of error must be considered.
So should we give much credibility to a study by MIT that a third runway at Heathrow is a bad idea?
The MIT study says that, compared to a new Thames Estuary airport (Boris Island), a third runway at Heathrow would cause more early deaths due to pollution. So that's it then, decision made.
However when questioned the authors admitted they had not included any of the following issues in their study:
* The cost of construction at either site
* The impact on local transport at either site
* The impact of extra road traffic too and from any new airport
* The external costs and benefits of either airport
Of course their defence was that they were only looking at health impacts of the two options and that is actually quite reasonable. It represents a contribution to the full cost-benefit analysis and a valuable one at that.
No comments:
Post a Comment