The author considers that the central fact of the work on traffic forecasting is the technique used to forecast the growth of car ownership, but that the conversion of this forecast into traffic growth, especially into trunk road traffic, raises a whole series of problems. It is suggested that there are a considerable number of techniques available for car ownership forecasting, depending on the data available for calibration. The Department of Transport's method of forecasting is described as that technique known as time series analysis, initially calibrated on licensing data, but now increasingly being used on census data at a local level. The use of this technique is discussed and compared with other techniques used by the Department of Transport, such as the cross-section technique used for car ownership forecasting in its national traffic model (NTM), and those used by British Rail and by the Greater London Council. The interaction between car purchase and car use in relation to land use and travel is examined, and the traffic implications of petrol prices and prices of public transport, and service levels, both in the short and long term are discussed. The basic assumption in a cross-section technique as compared with a time series analysis technique is that there is a stable relationship between car ownership, or some level of car ownership and income. Such differences are discussed, and emphasis is placed on the need to calibrate the model used, and to consider the validity of the data used for calibration, and its extent, and the specification of the actual indices used. /TRRL/

  • Corporate Authors:

    Embankment Press Limited

    Building 59, GEC Estate, East Lane
    Wembley, Middlesex HA9 7TQ,   England 
  • Authors:
    • Mogridge, MJH
  • Publication Date: 1977-8-9

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00174168
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Jun 28 1981 12:00AM