ABSTRACT

In this chapter we shall examine the demand for transport and the factors that influence the traveller to choose one mode of transport rather than another. The importance of analysing demand hardly needs emphasising, for in such long-lived investments as motorways, airports, docks and railways the skilful and accurate analysis of demand is a vital element of efficient investment decisions. Overinvestment is clearly wasteful, but underinvestment can prove expensive to remedy; it is difficult to add an additional lane to an existing motorway, for example . At the moment the demand for motor cars and motor travel dominates the pattern of travel, and so we shall devote some attention to demand studies; but modelling the total demand for travel and the way in which it is split among different modes has grown in importance recently and is now a vital part of transport planning, and in Chapter 3 we shall discuss models of passenger traffic.