SIMULATION OF TRAFFIC FLOW AT GRADE-SEPARATED INTERCHANGES

This paper gives an outline of a traffic simulation model that has been designed to study the effect of the geometric design and traffic composition of a road lay-out on individual drivers and vehicles, and to facilitate the presentation of the consequences of certain designs to those concerned. This model is limited to grade-separated intersections with a limited number of on- and off-ramps. Magnetovision is employed to give a display of traffic flow on a crt screen. The system uses a main program plus 18 sub-routines (in FORTRAN), the work described used an IBM 360/65 computer and required 168 k bytes of memory space. Inputs are road and traffic descriptions and outputs are travel time and delay for each vehicle with their means and the acceleration noise of the whole traffic system. Factors involved include acceleration/deceleration of vehicles, lateral acceleration, desired speed of the drivers, reaction time, gap acceptance, traffic characteristics, headway distribution based on tanner's m/d/1-queueing model, a car following model, and a simulation process where the model is up-dated according to an incrementation method. Validation studies involved an off-ramp, an on-ramp and the approach to a bridge (the roeda sten interchange), all in the gothenberg area. Graphs give examples of the distributions obtained by actual measurement and by the simulation model. The validation studies although limited, show that the model is likely to be useful. /TRRL/

  • Availability:
  • Corporate Authors:

    Printerhall Limited

    29 Newmart Street
    London W1P 3PE,   England 
  • Authors:
    • Wallman, C G
  • Publication Date: 1976-10

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Filing Info

  • Accession Number: 00149647
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Analytic
  • Files: ITRD, TRIS
  • Created Date: Jun 22 1977 12:00AM