TRAFFIC FORECASTING. PART 2

Part 2 of this two-part commentary on the department of transport's method of traffic forecasting is mainly concerned with car purchase and car use. The author suggests that whilst the growth of car ownership appears likely to continue, indeed to levels substantially in excess of the department's estimates, the level of car traffic arising therefrom is much more sensitive to policy on taxation and service levels, whether on trunk roads or generally, and that much more work needs to be done to evaluate what the best policies are for the community as a whole. The author states that the only source of data which simultaneously gives the expenditure on car purchase and car use for each household income level is the family expenditure survey. These data are discussed, and it is suggested that since the car owning sample is only about 4000 households per year, any conclusions must be considered as tentative. The proportion of disposable income allocated to car purchase and use is given as about 15 1/2 per cent, and this finding is discussed in relation to movements in the prices of fuel and the growing demand for increases in car size. The relationship between public and private transport is discussed, together with policy implications concerned with petrol taxation; bearing in mind that the major determinants of car ownership are considered to be incomes and car prices, but not fuel prices. /TRRL/