A DIGITAL SYSTEM FOR URBAN TRAFFIC FLOW DATA

The authors explain that the collection and analysis of the vast quantities of information required from many traffic surveys have always produced problems for the traffic engineer. The study described in this paper was undertaken in an attempt to reduce the overall time involved in such surveys. The site selected for the study survey was Leeds city centre, an area measuring approximately 2000 M in the east-west direction and 900 M in the north-south direction, and involved the analysis of the traffic during the evening peak period on 58 different streets. The study was confined to vehicles which were in motion or at a temporary halt and information concerning parked vehicles was not collected. The use of aerial photography to record traffic movements is described which involved taking black-and-white vertical photographs from a light aircraft using a camera with a focal length of 152.78 mm, a format of 228.6 mm by 228.6 mm and a contact scale of 1:4000. Time intervals between successive photographs was four seconds, and the shape of the survey area was such that it could be covered by one strip of photographs, (longitudinal overlap 80 per cent) and the strip of photography was repeated at 15 min intervals from 1600 h - 1800 h. Information from the photographs was collected in digital form, and analysis undertaken using a d-mac co-ordinate reader and a 1906a icl computer. Analysis techniques, the question of control points, street-by-street data collection methods and transformation techniques in relation to national grid co-ordinates are discussed. /TRRL/

  • Availability:
  • Corporate Authors:

    Printerhall Limited

    29 Newmart Street
    London W1P 3PE,   England 
  • Authors:
    • Garner, J B
    • UREN, J
  • Publication Date: 1978-8-9

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Filing Info

  • Accession Number: 00193983
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Jun 13 1979 12:00AM