DEAD AREAS ON ROUNDABOUTS AND TRAFFIC CAPACITY OF SMALL ROUNDABOUTS

THE CAPACITY OF JUNCTIONS IS THE LIMITING FACTOR IN ANY ROAD SYSTEM. IN CITIES, WHERE THE MAIN PROBLEM IS THE VERY HIGH PEAK VOLUMES AND LIMITED LAND RESOURCES, IT IS ESSENTIAL THAT THE MAXIMUM CAPACITY OF JUNCTIONS BE OBTAINED. A METHOD OF ACHIEVING THIS OBJECTIVE IN THE CASE OF ROUNDABOUTS IS DESCRIBED. IT APPEARS THAT THE COST OF IMPROVING THE EXISTING ROUNDABOUTS ON THE SUGGESTED LINES WOULD BE QUITE SMALL IN COMPARISON TO THE SUBSTANTIAL INCREASE IN CAPACITY ACHIEVED BY THIS METHOD. ROUNDABOUT CAPACITIES ARE USUALLY CALCULATED BY MEANS OF THE R.R.L. EQUATION GIVEN IN "ROADS IN URBAN AREAS", BUT THERE ARE MANY SMALL ROUNDABOUTS WHOSE GEOMETRIC PROPORTIONS ARE OUTSIDE THE LIMITS RECOMMENDED FOR THE USE OF THIS EQUATION. IN CONSEQUENCE, THEIR TRAFFIC CAPACITIES CANNOT READILY BE ESTIMATED. AN INVESTIGATION OF THE TRAFFIC CAPACITIES OF THESE SMALL ROUNDABOUTS WAS CONDUCTED SO THAT THEY COULD BE COMPARED WITH OTHER TYPES OF JUNCTION. THE TRAFFIC CAPACITIES DESCRIBED HAVE BEEN ACHIEVED ONLY SINCE THE INTRODUCTION OF THE "GIVE WAY" RULE AT ROUNDABOUTS. WITH THIS RULE, APPROACHING TRAFFIC GIVES WAY TO TRAFFIC ALREADY ON A ROUNDABOUT. /BPR/

  • Availability:
  • Supplemental Notes:
    • Vol 10, pp 610-614
  • Authors:
    • Bapat, P
    • Grant, E
  • Publication Date: 0

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  • Accession Number: 00227964
  • Record Type: Publication
  • Source Agency: Traffic Systems Reviews & Abstracts
  • Files: TRIS
  • Created Date: May 13 1970 12:00AM