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TRAFFIC CAPACITY

A SUMMARY IS PRESENTED OF A RESEARCH PROJECT TO DETERMINE CAPACITY OF TWO, THREE AND FOUR LANE ROADS. THE INFLUENCE OF THE PROPORTIONATE AMOUNT OF TRAFFIC IN ONE DIRECTION IS NOT MARKED ON 2-LANE ROADS UNTIL THE FRACTION INCREASES TO 80% OR MORE, WHEN A GREATER VOLUME OF TRAFFIC IS CARRIED WITHOUT CONGESTION. THE AVERAGE WORKING CAPACITY FOR 2-LANE ROADS IS APPROXIMATELY 95 PER 5-MINUTE INTERVAL OR 1000 PER HOUR. THREE-LANE ROADS APPEAR TO OPERATE TO SLIGHTLY BETTER ADVANTAGE WHEN 70% OF THE TRAFFIC IS IN ONE DIRECTION. THE AVERAGE WORKING CAPACITY IS APPROXIMATELY 180 PER FIVE-MINUTE INTERVAL OR 2000 PER HOUR. FOUR-LANE ROADS HAVE AN AVERAGE WORKING CAPACITY OF 290 VEHICLES PER 5-MINUTE INTERVAL. THE ADDITION OF ONE LANE TO A 2-LANE ROAD INCREASES ITS WORK 50% AND ITS CAPACITY 100%. ADDITION OF TWO LANES INCREASES THE WIDTH BY 100% AND THE CAPACITY BY 200%. HOWEVER, THIS STUDY RELATES TO TRAFFIC CAPACITY ONLY AND NO CONSIDERATION WAS GIVEN TO THE RELATIVE SAFETY OF THE VARIOUS LANE DESIGNS UNDER VARYING VOLUMES OF TRAFFIC.

  • Record URL:
  • Supplemental Notes:
    • Vol 11, Pt 1, PP 409-412, 2 FIG, 1 TAB. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
  • Authors:
    • Johnson, A N
  • Publication Date: 1932

Media Info

  • Media Type: Digital/other
  • Monograph Title: Proceedings of the Eleventh Annual Meeting of the Highway Research Board Held at Washington, D.C. December 10-11, 1931. Part I: Reports of Research Committees and Papers
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00227991
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jun 1 1971 12:00AM