Intelligent Roadway Information System


ClearGuide is a mobility intelligence system that provides real-time route and workzone delay, travel time and other data. The ClearGuide device driver comm link URL specifies the HTTPS address of a ClearGuide server. The controller associated with the comm link requires the password field to contain both the user name and password in the form username:password. The system attribute clearguide_key should also be specified to indicate the ClearGuide agency name.

ClearGuide Action Tag

Real-time ClearGuide data can be embedded in DMS messages using DMS actions. A [cg ] action tag in the message pattern will be replaced by the appropriate value. The action tag has the following format:

[cg dms,wid,min,mode,idx ]


  1. dms: Name of DMS associated with the workzone defined in ClearGuide
  2. wid: The workzone ID defined in ClearGuide
  3. min: The minimum acceptable value for the statistic read from ClearGuide
  4. mode: An identifier for the desired ClearGuide statistic:
    • tt: workzone travel time calculated as max(tta, ttsl)
    • ttsl: workzone travel time at the speed limit
    • tta: actual travel time, may be > ttsl
    • delay: workzone delay
    • sp: workzone speed
  5. idx: The zero-based index of the workzone associated with the DMS. This only applies for DMS with more than 1 associated workzone. It is optional and defaults to zero.