Samenvatting
The attempt to provide a formal framework for making decisions about highway (and other) investments is generally seen to have reached a peak with the application of cost benefit analysis. The unhappiness felt about the use of this technique resulted in the adoption of a more general framework approach with no explicit decision methodology. It is argued that the resulting decision- making process is too complex to proceed without formal assistance and that fuzzy set theory offers a sufficiently flexible methodology to enable the essentially linguistic constructs typical of argument and debate to be used.