ABSTRACT
The next three chapters will deal with what is frequently regarded as the heart of cost benefit analysis: the imputation of money values to those items of cost and benefit — in the terms of this book, principally the components of user cost — for which no money equivalent exist. If the framework for appraisal developed in Chapters 2 to 4 is to make its full contribution, a way must be found of combining the various components of user cost, and hence changes therein, into a single index including not simply travel time and money, i.e. the components of generalised cost, but any other aspects of making a trip which give rise to utility or disutility. As was indicated in Chapter 1, the common unit which is normally employed in cost benefit analysis is money: many items of user cost such as fares and vehicle operating costs have a direct money equivalent as do most of the costs of transport provision and so, in most (though not all) circumstances, it has seemed simplest to make it the unit in which relative values are expressed. Subject to the qualification made in Chapter 1 ways must therefore be found of determining what weight, in money terms, individuals attach to these various components. This chapter is concerned with the methods which economists and others have applied to this problem: subsequent chapters describe the results obtained from applying these methods for the main items of user costs — travel time savings, safety, journey time reliability and comfort and for non-user costs, i.e. those items of cost which transport users impose on others — noise, fumes and other items of disamenity.
