FIVE-MINUTE-CLUSTER SAMPLING FOR DETERMINING URBAN TRAFFIC VOLUMES

A STUDY WAS CONDUCTED TO SHOW THAT RANDOM SAMPLING CAN BE MODIFIED BY CLUSTER SAMPLING TO PRODUCE PRACTICAL AND ECONOMICAL FIELD SAMPLING. THIS METHOD ALLOWS A RELIABLE MEASURE OF URBAN TRAFFIC VOLUMES. THE PRINCIPLES GOVERNING THE CLUSTER SAMPLING METHOD USED ARE: (1) IT IS ASSUMED THAT TRAVEL TIME BETWEEN ADJACENT STATIONS WOULD REQUIRE 5 MINUTES DUE TO DATA'S BEING RECORDED BY 5 MINUTE INTERVALS, (2) THE INTERVAL IN THE FIRST HOUR OF EACH SAMPLE WAS SELECTED BY USING A SERIES OF RANDOM NUMBERS. (3) ASSUMPTIONS WERE MADE FOR INTERVALS DRAWN FOR OBSERVATION OF AN ODD 5 MINUTE INTERVAL AND AN EVEN 5 MINUTE INTERVAL, AND (4) THE OBSERVATION INTERVAL SELECTED WAS BASED ON A FORMULA WHICH WOULD PERMIT THE UNBIASED SELECTION OF THE INTERVAL BY USE OF RANDOM NUMBERS BUT AT THE SAME TIME LIMIT TRAVEL TO 5 MINUTES TO PERMIT TAKING 5 MINUTE SAMPLES AT 6 STATIONS PER HOUR OR 10 MINUTE SAMPLES AT 4 STATIONS PER HOUR BY EACH FIELD TEAM. COMPARISONS ARE PRESENTED IN TABULAR FORM AS STATISTICAL ANALYSIS OF URBAN TRAFFIC BY RANDOM AND CLUSTER SAMPLING. THE TRAVEL TIME BETWEEN STATIONS OBSERVED IS A CONTROLLING FACTOR IN THE EFFICIENT UTILIZATION OF THE CLUSTER SAMPLING PROCEDURE. THERE APPEAR TO BE MINIMUM VOLUME LIMITS TO THE USE OF THIS SAMPLING METHOD IN RELATION TO ITS ACCEPTABLE ACCURACY. THE ACCURACY OF THE METHOD DEPENDS UPON THE TRAINING AND THE INTEREST OF THE OBSERVERS. THE STUDY INDICATES THAT THE CLUSTER SAMPLING METHOD CAN BE EFFICIENTLY AND ECONOMICALLY USED UNDER CERTAIN CONDITIONS FOR RELIABLY ESTIMATING URBAN TRAFFIC VOLUMES WITHIN ACCEPTABLE LIMITS OF ERROR.

  • Supplemental Notes:
    • Vol 34, pp 502-507, 2 TAB, 4 REF, 1 APP
  • Authors:
    • Adams, W T
  • Publication Date: 1955

Language

  • English

Media Info

  • Monograph Title: Proceedings of the Thirty-Fourth Annual Meeting of the Highway Research Board, Washington, D.C., January 11-14, 1955
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00227741
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 15 2004 2:36AM