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THE TRAFFIC ANALYSER : AN INSTRUMENT FOR THE AUTOMATIC MEASUREMENT OF TRAFFIC PARAMETERS AN INTEGRATED DATA SYSTEM FOR STUDYING TRAFFIC FLOW

THE TRAFFIC ANALYSER DESCRIBED IN THE FIRST PAPER IS CAPABLE OF AUTOMATICALLY MEASURING VEHICLE HEADWAY, VELOCITY, ACCELERATION AND LENGTH. VEHICLE DATA ARE OBTAINED BY MEANS OF A PRESENCE DETECTOR CONSISTING OF A PAIR OF PHOTELECTRIC CELLS SPACED A KNOWN DISTANCE APART. SIGNALS FROM EACH CELL ARE COMBINED AND RECORDED ON A SINGLE CHANNEL OF A 7-CHANNEL ANALOGUE MAGNETIC TAPE RECORDER. THE OUTPUT OF UP TO SEVEN OF THESE DETECTORS CAN BE RECORDED SIMULTANEOUSLY. THE RECORDED SIGNAL IS SUBSEQUENTLY REPRODUCED INTO THE DATA PROCESSING UNIT LOCATED IN THE LABORATORY. THE DATA SIGNAL CONTAINS FOUR TRANSITION POINTS FOR EACH VEHICLE (VEHICLE FRONT PASSING OVER CENTERLINE OF EACH DETECTOR CELL, SIMILARLY THE REAR CLEARING EACH CELL). THE TIMES BETWEEN EACH TRANSITION ARE MEASURED AND RECORDED IN CODED DIGITAL FORM ON PAPER TAPE. THE PAPER TAPE DATA ARE THEN FED INTO A COMPUTER WHICH OBTAINS HEADWAY DIRECTLY FROM THE FIRST TIME CODE OF EACH GROUP, AND FROM THE REMAINING CODES, TWO VALUES OF VELOCITY (CORRESPONDING TO THE FRONT AND REAR OF THE VEHICLE), ACCELERATION (BY DIFFERENCING THE VELOCITIES), AND VEHICLE LENGHT. THE SECOND PAPER DESCRIBES A SYSTEM USED TO STUDY THE BEHAVIOR OF TRAFFIC FLOW ON RURAL ROADS. IT CONSISTS OF ELECTRICAL CONTACT SWITCHES PLACED ON THE ROADWAY AND CONNECTED TO A PORTABLE TAPE RECORDER VIA AN OSCILLATOR UNIT. THE PASSAGE OF VEHICLES IS AUTOMATICALLY RECORDED BY MODUALTIONS OF A STANDARD FREQUENCY SIGNAL. SIMULTANEOUSLY A VERBAL COMMENTARY DESCRIBING THE VEHICLES IS MADE USING A SECOND TRACK ON THE MAGNETIC TAPE. THE ENTIRE FIELD EQUIPMENT IS SELF-CONTAINED AND MAY BE CARRIED, INSTALLED AND OPERATED BY ONE PERSON. UPON COMPLETION OF THE FIELD RECORDINGS THE MAGNETIC TAPES ARE BROUGHT TO THE LABORATORY AND TRANSCRIBED IN TERMS OF ITS CLASS, DIRECTION OF TRAVEL, LANE VELOCITY, VARIOUS HEADWAY TIMES AND DISTANCES TO VEHICLES IN THE IMMEDIATE VICINITY, TOGETHER WITH SIMILAR TYPES OF INFORMATION ON THESE ADJACENT VEHICLES. THE SYSTEM MAY BE USED ON EITHER TWO- OR THREE-LANE SINGLE/DUAL CARRIAGEWAYS UNDER FIVE VISIBILITY CONDITIONS. THE VEHICLE PARAMETERS ARE TABULATED IN THREE PRINCIPAL FORMS: AS VELOCITY FREQUENCY DISTRIBUTIONS, AS VELOCITY HEADWAY FREQUENCY DISTRIBUTIONS (BOTH OF WHICH MAY BE OUTPUT IN GRAPHICAL FORM FOR EASE OF ANALYSIS) AND AS FREQUENCY DISTRIBUTIONS DESCRIBING THE BEHAVIOR OF VEHICLES TRAVELLING IN PLATOONS, AND OF VEHICLES TRAVELLING SINGLY WHICH MAY BE INFLUENCED BY THE PROXIMITY OF OTHER VEHICLES IN AN ADJACENT LANE. /AUTH./

  • Supplemental Notes:
    • Vol 4, Pt 1, PP 739-760; 761-784
  • Corporate Authors:

    ARRB

    Melbourne, Victoria  Australia 
  • Authors:
    • Keith, R J
    • Yan, S T
    • O'FLAHERTY, C A
    • Williams, L K
    • Harrison, M
  • Conference:
  • Publication Date: 0

Media Info

  • Serial:
    • Issue Number: 0

Subject/Index Terms

Filing Info

  • Accession Number: 00227262
  • Record Type: Publication
  • Source Agency: Traffic Systems Reviews & Abstracts
  • Files: TRIS
  • Created Date: Jul 27 1970 12:00AM