The object of the report is to reconsider the methods used to forecast kilometres per car at an average national level. Such forecasts are used as an input to the national traffic forecasts. The first part gives various sets of time-series and cross-section data and draws certain conclusions about the effects of incomes, petrol prices and car speeds. A simple constant-elasticity model is then developed; it is used to illustrate the effects of a range of assumptions about the future. An alternative modelof car ownership and use is then proposed. This has a disaggregate causal structure and uses ideas of utility maximisation and constant travel budgets. The forecasts from both models cover a wide range; at the centre of the range of the assumptions, they indicate little change in kilometres per car up to the year 2010. It is concluded that at its present stage of development the causal model is less satisfactory than the simple model. (Author/publisher)
Abstract