The recent publication of the report by the Standing Advisory Committee on Trunk Road Assessment (SACTRA) on 'Trunk Roads and the Generation of Traffic' has placed the issue of scheme evaluation firmly in the public spotlight. A key finding of SACTRA was that new road capacity does result in induced traffic whose degree differs from scheme to scheme. This finding runs counter to the assumptions inherent in existing DoT guidelines for traffic forecasting and scheme appraisal in which the so called 'fixed trip matrix' (FTM) assumption is central. In anticipation of these findings and as part of an extensive research programme, WS Atkins were commissioned by the DoT to investigate the practical issues involved in variable trip matrix (VTM) scheme assessment methods. The research, scheduled to extend over a five month period, requires evaluation of a range of options for VTM scheme assessment on a series of representative networks and to compare results with those from the FTM case. The aim of the study is to evaluate the relative performances of the various methods both in terms of the results of the example appraisal and the ease of applicability. The methods to be assessed include both link based approaches similar to those found in existing (FTM) methods such as COBA and URECA and more conventional matrix based 'consumer surplus' approaches. Based on these practical assessments, the study makes recommendations on the most appropriate method for possible inclusion in DoT guidelines for scheme appraisal. (A) An abstract only of this paper appears in the seminar proceedings. For the covering abstract see IRRD 880168.


  • English

Media Info

  • Pagination: p. 207

Subject/Index Terms

Filing Info

  • Accession Number: 00724209
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • ISBN: 0-86050-283-X
  • Files: ITRD
  • Created Date: Aug 19 1996 12:00AM