INVESTIGATION OF TRAFFIC FLOW ON EXITS FROM GRADE SEPARATED JUNCTIONS WITH LANE REDUCTION

UNTERSUCHUNG DES VERKEHRSABLAUFES AN AUSFAHRTEN VON PLANFREIEN KNOTENPUNKTEN MIT SPURSUBSTRAKTION

The investigation consisted of examining the traffic flow macroscopically with video cameras and microscopically with induction loops on a stretch of three-lane motorway 1,4 km long to the north of the motorway triangle Horst with reference to traffic capacity and safety. Comparative measurements were carried out with video cameras 3 and 6 km to the north of the exit. Multiple regression analyses were carried out for the parameters specific lane density and lane transfer in dependence on traffic density, traffic composition, proportion of traffic leaving the motorway and the distance from the exit leading to the development of a theoretical model (based on considering the traffic process as an inhomogeneous Markov process) with which the observed relationships may be described with reasonable accuracy. On the basis of the results it can be shown that the type of lane subtraction examined and within the limits of traffic density according to the table of RAL-Q-74 does not lead to capacity problems with regard to lane density and lane interchange, provided that the ratio 70:30 between high and low density streams is not exceeded; that the parameters are clearly influenced by the signposting and that the rejection of the type of lane reduction in which the lefthand lane of the ramp starts at the point of the island is not justified on grounds of safety. On the basis of a hypothetical comparison with lane reduction as suggested in RAL-K-74 it is surmised that the type of lane reduction examined is at least equivalent. A more definite assertion will be possible only after further comparative measurements at established test stations. /TRRL/

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  • Corporate Authors:

    Bundesminister fuer Verkehr

    ABT. Strassenbau, Lennestrasse 30
    D-5300 Bonn,   Germany 
  • Authors:
    • MEINEFELD, P
  • Publication Date: 1976

Language

  • German

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00195201
  • Record Type: Publication
  • Source Agency: Bundesanstalt für Straßenwesen (BASt)
  • Report/Paper Numbers: Monograph
  • Files: ITRD, TRIS
  • Created Date: Jul 11 1979 12:00AM