CHANGES IN SPEEDS OF VEHICLES ON HORIZONTAL CURVES

AN ESSENTIAL PART OF THE TRAFFIC SIMULATION MODEL BEING DEVELOPED AT THE NATIONAL SWEDISH ROAD RESEARCH INSTITUTE IS A DESCRIPTION OF THE VARIATIONS IN THE SPEED OF ROAD VEHICLES ON HORIZONTAL CURVES. STUDIES OF THE SPEED ADAPTATION ON HORIZONTAL CURVES CONDUCTED BY THE ROAD RESEARCH INSTITUTE WERE CARRIED OUT UNDER LEFT-HAND TRAFFIC CONDITIONS. IT WAS THOUGHT DESIRABLE TO EXAMINE THE EFFECT PRODUCED BY RIGHT-HAND TRAFFIC ON THE SPEEDS OF VEHICLES ON CURVES. INVESTIGATIONS WERE CONDUCTED AT PLACES WHERE SIMILAR MEASUREMENTS HAD BEEN TAKEN IN LEFT-HAND TRAFFIC, SO THAT REFERENCE DATA WERE AVAILABLE. THE FIRST INVESTIGATION STUDIED FREE- MOVING VEHICLES. THESE ARE DEFINED AS VEHICLES SEPARATED BY A TIME GAP OF AT LEAST 6 SECONDS FROM THE VEHICLE AHEAD. THE RESULTS OF THESE INVESTIGATIONS PROVED TO BE IN CLOSE AGREEMENT WITH THOSE OF TARAGIN'S TESTS CARRIED OUT IN 1954. IT WAS FOUND, THAT THE SPEED ADAPTATION TOOK PLACE IN MOST CASES BEFORE THE CURVE, AND WAS THEN MAINTAINED CONSTANT THROUGHOUT THE CURVE. FURTHERMORE, THE DIFFERENCE IN SPEED BETWEEN THE VEHICLES MOVING IN THE INNER AND OUTER TRAFFIC LANES WAS VERY SLIGHT. IN ANOTHER INVESTIGATION, THE VARIATION IN THE SPEED OF EACH VEHICLE WITH THE DISTANCE WAS DETERMINED BY MEASURING THE TRAVEL TIME OVER 8 CONSECUTIVE ROAD SECTIONS. THIS INVESTIGATION WAS CARRIED OUT ON FREE-MOVING VEHICLES AT 25 PLACES IN CENTRAL SWEDEN, AND COVERED 1,200 VEHICLES IN ALL. /TRRL/

  • Supplemental Notes:
    • Rpt No 104, 5 PP, 3 FIG
  • Authors:
    • Holmquist, C
  • Publication Date: 0

Language

  • English

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Filing Info

  • Accession Number: 00227779
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: TRIS
  • Created Date: Feb 15 1972 12:00AM