DATA TRANSMISSION IN AREA TRAFFIC CONTROL

DATA TRANSMISSION IS BASIC TO ANY CONCEPT OF COORDINATED TRAFFIC CONTROL. THE RAW TRAFFIC DATA HAVE TO BE TRANSMITTED TO THE CONTROL ROOM AND THEN THE PROCESSED INFORMATION (IN THE FORM OF SIGNALS TO CONTROLLERS) HAS TO BE SENT BACK TO THE ACTUAL TRAFFIC SITES. A SIMPLE INTERSECTION HAS TEN DATA SOURCES (ONE EACH FOR THE TWO TRAFFIC LIGHTS AND TWO EACH FOR THE FOUR APPROACHES TO THE INTERSECTION FOR FLOW AND SATURATION). A SEPARATE PHONE LINE FOR EACH KIND OF DATA WOULD BE MUCH TOO EXPENSIVE. THEREFORE ONLY ONE PHONE LINE IS USED TO SEND THE INFORMATION. THIS CONCEPT IS CALLED MULTIPLEXING. TWO WAYS OF DOING IT ARE BY DEDICATING (1) A PARTICULAR FREQUENCY CHANNEL ON EACH PHONE LINE TO EACH KIND OF DATA OR (2) A PARTICULAR INTERVAL OF TIME TO EACH KIND OF DATA. THE LATTER (TIME DIVISION MULTIPLEXING) IS THE ONE USED HERE BECAUSE OF ITS MANY ADVANTAGES. AN EXAMPLE IS GIVEN FOR A SYSTEM WHICH HAS BEEN OPERATIONAL IN LONDON SINCE APRIL, 1967. BINARY CODES ARE USED ALONG WITH VARIOUS CHECKING BITS. /BPR/

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00410683
• Supplemental Notes:
  • Vol 9, pp 608-612
• Authors:
  • Tillotson, H T
• Publication Date: 1968-4

Media Info

• Serial:
  • Traffic Engineering & Control
  • Publisher: Hemming Group, Limited
  • ISSN: 0041-0683
  • Serial URL: http://www.tecmagazine.com/

Subject/Index Terms

• TRT Terms: Data communications; Telephone; Time division multiplexing; Traffic control
• Old TRIS Terms: Binary systems
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00225518
• Record Type: Publication
• Source Agency: Traffic Systems Reviews & Abstracts
• Files: TRIS
• Created Date: Oct 7 1994 12:00AM