CABLELESS LINKING OF TRAFFIC SIGNALS

THE PLESSEY CABLELESS LINKING SYSTEM FOR COORDINATING THE OPERATION OF A NUMBER OF TRAFFIC SIGNAL CONTROLLERS BY MEANS OF MAINS-SYNCHRONISED CLOCKS IS DESCRIBED. AT EACH INTERSECTION AN AUXILIARY UNIT PROVIDING TIMINGS USED IN THE LINKING IS INTERFACED WITH THE NORMAL SIGNAL CONTROLLER. DIFFERENT TIMING PLANS CAN BE USED AS THE TRAFFIC FLOW CHANGES DURING THE COURSE OF THE DAY. FOR EACH PLAN ALL LINKED CONTROLLERS HAVE A COMMON CYCLE TIME. THE ELECTRONIC COMPONENTS OF THE LINKED UNIT ARE DESCRIBED AND THE PROCEDURE FOR SETTING UP AND OPERATING THE SYSTEM IS ILLUSTRATED WITH EXAMPLES. IN THE EVENT OF MAINS FAILURE A BATTERY ALLOWS THE UNIT TO OPERATE FOR AT LEAST 4 HOURS WITH PULSES FROM A CRYSTAL-CONTROLLED OSCILLATOR REPLACING THE MAINS FREQUENCY SYNCHRONISED TIMING PULSES. IF THE VOLTAGE FALLS BELOW A CRITICAL VALUE THE UNIT IS SWITCHED TO THE ISOLATED CONDITION UNTIL POWER IS RESTORED AND THE CLOCK AND TIMINGS HAVE BEEN CHECKED. IN ADDITION TO LINKING SIGNALS ALONG A ROUTE, THE SYSTEM CAN BE USED AS AN AREA CONTROL SCHEME FOR TOWNS TOO SMALL TO WARRANT COMPUTER CONTROL, OR IN CONJUNCTION WITH COMPUTER CONTROLLED SCHEMES, EITHER AS A STAND BY SYSTEM OR ON THE APPROACHES TO THE MAIN CONTROLLED AREA.

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  • Corporate Authors:

    Printerhall Limited

    29 Newmart Street
    London W1P 3PE,   England 

    Printerhall Limited

    29 Newmart Street
    London W1P 3PE,   England 
  • Authors:
    • Rudland, P
  • Publication Date: 1973-5

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Filing Info

  • Accession Number: 00080686
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Mar 6 1975 12:00AM