In an effort to improve the operations of both portable and permanent (fixed-site) variable message signs (VMSs) in Virginia, a comprehensive research effort to develop operational guidelines was undertaken. These guidelines, presented in the form of users' manuals, were based on information obtained from the literature, VMS operators, and motorists. Issues addressed by the manuals include whether to use a VMS, where to place a portable VMS, and how to design a VMS message. The manuals are not simply a list of predefined messages; instead, they are composed of concise, readable modules designed to guide an operator through the thought process required to use a VMS effectively. An operator follows a logical decision tree as each module is completed, allowing effective use of the VMS as well as training the operator for use of the device. Key lessons learned in developing two such manuals for portable and permanent VMSs are highlighted. On the basis of theoretical calculations and motorists' experiences, it is strongly recommended that a VMS use no more than two message screens. A single message screen is preferred. VMSs should be used only to advise drivers of changed traffic conditions and to convey specific traffic information concisely. Because of limited information capabilities, VMSs should be used in conjunction with other means of communication such as highway advisory radio and static signs. Most importantly, it is crucial that credibility be maintained. Incorrect information can have disastrous consequences on VMS effectiveness.


  • English

Media Info

  • Features: Figures; References;
  • Pagination: p. 1-8
  • Monograph Title: Traffic control devices, visibility, and railroad grade crossings
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00714874
  • Record Type: Publication
  • ISBN: 0309061601
  • Files: TRIS, TRB
  • Created Date: Dec 12 1995 12:00AM