APPLICATION OF STATISTICAL SAMPLING METHODS TO TRAFFIC PERFORMANCE AT URBAN INTERSECTIONS

THE FREQUENCY OF TIME SPACINGS BETWEEN SUCCESSIVE VEHICLES WAS FOUND TO COINCIDE VERY CLOSELY WITH THE THEORETICAL SPACING GIVEN BY THE POISSON LAW. THE DIFFERENCES IN THE SPACINGS ARE INSIGNIFICANT EXCEPT FOR THOSE LESS THAN 1 SEC. DUE TO THE LENGTHS OF VEHICLES AND THE SPACING REQUIRED BY DRIVERS TO AVOID REAR END COLLISIONS, IT IS OBVIOUS THAT THERE SHOULD BE RELATIVELY FEW SPACINGS IN MOVING TRAFFIC UNDER ONE SECOND COMPARED TO THE THEORETICAL SERIES WHICH REFERS TO DIMENSIONLESS POINTS. IN CERTAIN CALCULATIONS, SUCH AS DELAY AT SIGNALIZED INTERSECTIONS, IT IS NOT THE DISTRIBUTION OF SPACINGS THAT IS USED, BUT THE NUMBER OF VEHICLES APPEARING IN A GIVEN TIME INTERVAL. FOR RELATIVELY LARGE TIME INTERVALS, SAY ABOUT 15 SECONDS, THE DISTRIBUTION HOLDS VERY CLOSELY TO THE RANDOM SERIES. OFTEN VERY LITTLE CALCULATION IS NECESSARY TO ARRIVE AT RESULTS, FOR THERE ARE PUBLISHED TABLES GIVING BOTH THE INDIVIDUAL AND THE CUMULATED TERMS OF THE POISSON SERIES. WITH TRAFFIC BEHAVIOR CONFORMING TO THE POISSON SERIES, IT IS EXPECTED THAT THE TECHNIQUES OF SAMPLING AND CONTROL FOUND VALUABLE IN INDUSTRY WILL FIND INCREASING USE IN TRAFFIC CONTROL AND REGULATION. /AUTHOR/

  • Supplemental Notes:
    • Vol 26, pp 377-389, 7 FIG, 3 TAB, 8 REF
  • Authors:
    • Greenshields, B D
  • Publication Date: 1947

Media Info

  • Monograph Title: Proceedings of the Twenty-Sixth Annual Meeting of the Highway Research Board Held at Washington, D.C. December 5-8, 1946
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00225988
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jun 5 1972 12:00AM