TRAFFIC FORECAST ERRORS HIGHLIGHTED

A catalogue of traffic forecast errors is highlighted in the national audit office (nao) report on road planning procedures at the Department of Transport and its Scottish and Welsh counterparts. In the nao's view, 225 million was spent by the dtp on providing 41 road schemes that did not subsequently reach the estimated levels of traffic. Conversely, the nao's believe there was 160 million underspent by the dtp on 27 other schemes, including the M25 London orbital motorway. The dtp aims at limiting to 20% the disparities between original traffic forecasts and actual traffic flow, but nao's analyses show there are many cases where the variation is well outside this range. The differences are attributed by dtp to: (1) overestimation of traffic transferring to the new road; (2) no allowance for generated and redistributed traffic; (3) underestimation of national traffic growth; (4) wide variations in regional traffic growth; and (5) land not being used as expected.

Language

  • English

Media Info

  • Pagination: p. 3
  • Serial:
    • CONTRACT JOURNAL
    • Publisher: Reed Business Information, Limited
    • ISSN: 0010-7859

Subject/Index Terms

Filing Info

  • Accession Number: 00483397
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: May 31 1989 12:00AM