CHOOSING A LOCAL CONTROL FOR VARIABLE MESSAGE SIGNS

It is shown how the choice of a local control device is an important aspect of using variable message signs, and how an emergency control function is needed to assure system continuity. In the specific case described here, planners chose a local controller which was brought to the faulting location and manually connected to the sign to affect the message display. Messages had to be created for downloading to the sign's randomly accessible memory for display on the signboard face, and messages had to be indexed from the sign controller's nonvolatile read-only memory. Specifications required use of a hand-held controller unit that is able to store a program, can communicate with the sign's controller, can select or create messages for display, and can provide basic security through individual sign site address functions. A TANDY Model 100 portable microcomputer qualified as acceptable. With addition of a cassette tape recorder, the system program required to interface to the sign's controller could be backed up on another medium. Thus system operation was insulated from various types of operator error, battery failures, and electronic failures which could interfere with operations by loss of programmed memory. The benefits and drawbacks of laptop computer use are noted.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/1519687
• Publication Date: 1987-3

Media Info

• Pagination: p. 24-25
• Serial:
  • Better Roads
  • Volume: 57
  • Issue Number: 3
  • Publisher: James Informational Media, Incorporated
  • ISSN: 0006-0208
  • Serial URL: http://www.betterroads.com

Subject/Index Terms

• TRT Terms: Computer programs; Errors; Failure; Microcomputers; Traffic control devices; Variable message signs
• Subject Areas: Highways; Operations and Traffic Management; I73: Traffic Control;

Filing Info

• Accession Number: 00463125
• Record Type: Publication
• Files: TRIS
• Created Date: Mar 31 1987 12:00AM