TRAFFIC FLOW DATA ACQUISITION USING MAGNETIC-LOOP VEHICLE DETECTORS

ONE MEANS OF ACQUIRING VALIDATION DATA FOR DIGITAL COMPUTER SIMULATION OF TRAFFIC FLOW IN A FREEWAY DIAMOND INTERCHANGE WILL BE THROUGH THE USE OF MAGNETIC-LOOP VEHICLE DETECTORS. ACTUAL INTERCHANGE PERFORMANCE WILL BE MONITORED BY DIRECT MEASUREMENT OF VEHICLE PARAMETERS /COUNT, SIZE, AND VELOCITY/, LEADING EVENTUALLY, THROUGH THE VALIDATION PROCESS, TO A REALISTIC SIMULATION MODEL. TECHNIQUES WERE DEVELOPED TO EXTEND EXISTING LOOP-DETECTOR CAPABILITIES, PERMITTING DIRECT MEASUREMENT OF VEHICLE PARAMETERS /MEASUREMENTS WERE AVAILABLE HERETOFORE ONLY ON A STATISTICAL BASIS/ AND EXPERIMENTS WERE CONDUCTED TO DETERMINE DETECTOR/ SENSOR-LOOP RESPONSE CHARACTERISTICS. A PRACTICAL SENSOR-LOOP CONFIGURATION, WHICH WAS DEVELOPED FOR THE VALIDATION RUNS AND TESTED IN CONTROLLED EXPERIMENTS, PROVIDED AN ACCURATE PICTURE OF THE OVER-ALL TRAFFIC PATTERN. MEASUREMENT ACCURACY WAS INVESTIGATED, CONSIDERING THE EFFECTS OF VARYING VEHICLE HEIGHT AND OF CLOSELY FOLLOWING VEHICLES /TAILGATING/, SUCH AS MIGHT BE EXPECTED IN HEAVY TRAFFIC. MEASUREMENT ERRORS DUE TO TAILGATING WERE ATTRIBUTABLE TO RECOVERY-TIME LIMITATIONS INHERENT IN THE LOOP-DETECTOR CIRCUIT. THE TECHNIQUES DESCRIBED IN THIS PAPER CAN BE USED, EMPLOYING COMMERCIAL LOOP-DETECTORS, FOR TRAFFIC APPLICATIONS IN WHICH IT IS DESIRED TO DETERMINE VEHICLE VELOCITY AND/OR SIZE DIRECTLY IN ADDITION TO VEHICLE COUNTING. /AUTHOR/

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  • Supplemental Notes:
    • Paper sponsored by Committee on Characteristics of Traffic Flow and presented at the 45th Annual Meeting. 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:
    • Stern, Stan
  • Publication Date: 1967

Language

  • English

Media Info

  • Media Type: Print
  • Features: Appendices; Figures; References; Tables;
  • Pagination: pp 38-52
  • Monograph Title: Traffic flow characteristics
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00227655
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 15 2004 2:36AM