In 1972 the changeable message sign subcommittee conducted a large scale survey to establish the state-of-the-art in use of changeable message signs (CMS). In part one, 300 traffic engineers throughout the U.S. were polled concerning CMS application. Twenty-four percent of the 280 who responded indicated that their agency either has used or plans to use changeable message signs. The most frequently reported applications for CMS were to inform motorists of (1) turn prohibition at street intersections and (2) reversible lanes. Only 11 of 67 reporting agencies reported Standard specifications; 45 agencies do their own maintenance while 11 indicated that it is contracted out. In part two, the subcommittee conducted a survey of all known manufactures of CMS in order to identify the types of CMS presently being used. Eight companies responded to this survey. The variable matrix type CMS is the most popular type which is produced by 6 different companies. The drum type is produced by two companies. One company manufactures the Varicom CMS. From the two surveys, it is apparent that there are several different types of CMS on the market today. They vary in their initial cost, their flexibility in displaying messages, their cost of operation and maintenance, and the way their message is displayed. In many cases, appurtenances have employed the CMS for various reasons with the resulting installation becoming a sign system intended for a specific purpose at a specific location. CMS are being used to guide traffic, regulate traffic, warn traffic, and inform traffic. Some SMC have standard shape, color and message and conform to the muted, but most do not. CMS have been employed with fixed message signs in some cases, but most often are installed by themselves. CMS have been used to treat a specific problem at a single location with limited message flexibility needed or provided. They have also been employed as components of very sophisticated traffic control and driver information systems with almost unlimited message flexibility and computerized system control.

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Filing Info

  • Accession Number: 00272050
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Oct 5 1974 12:00AM