German specifications evaluate traffic quality by means of design traffic flow; this is defined as the mean travel speed of the car. The author demonstrates with the aid of measurements, a mathematical model and simulation calculations, how the mean travel speed drops with increase in the traffic flow. An increase in the proportion of lorries also results in a drop in the travel speed. It is proposed that the proportion of lorries be expressed as a percentage and not as an absolute value as has been done in the ral - q 1974 regulations. As hitherto the traffic flow in the two directions has been divided in two, the influence of an uneven distribution of total traffic flow in each direction was studied in regard to the effect on traffic speed. An effect is only noticeable when less than 300 vehicles per hour travel in one direction. The question is raised whether the travel speed is suitable as an improtant parameter for the classification of traffic quality, as a sharp increase in the traffic load may be contrasted with only a limited increase in speed. (TRRL)

  • Availability:
  • Corporate Authors:

    Verlag fuer Publizataet

    Auf der heide 20
    300 Isernhagen HB, Hannover,   Germany 
  • Authors:
    • Brilon, W
  • Publication Date: 1977-12


  • German

Media Info

  • Features: Figures; References;
  • Pagination: p. 9-14
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00311904
  • Record Type: Publication
  • Source Agency: Bundesanstalt für Straßenwesen (BASt)
  • Files: ITRD, TRIS
  • Created Date: May 21 1981 12:00AM