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/
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Supplemental Notes:
- Vol 26, pp 377-389, 7 FIG, 3 TAB, 8 REF. 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.
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Authors:
- Greenshields, B D
- Publication Date: 1947
Media Info
- Media Type: Digital/other
- Monograph Title: Proceedings of the Twenty-Sixth Annual Meeting of the Highway Research Board Held at Washington, D.C. December 5-8, 1946
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Serial:
- Highway Research Board Proceedings
- Volume: 26
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Analysis; Headways; Intersections; Poisson ratio; Rear end crashes; Statistical sampling; Traffic
- Uncontrolled Terms: Traffic analysis
- Old TRIS Terms: Poissons ratio
- Subject Areas: Data and Information Technology; Highways; Operations and Traffic Management;
Filing Info
- Accession Number: 00225988
- Record Type: Publication
- Files: TRIS, TRB
- Created Date: Jun 5 1972 12:00AM