Variable message sign is also known as a dynamic message sign. It provides information related to safety, weather and traffic conditions that may prevail on the road perpetually. The Variable message boards may be controlled centrally & can be pre – programmed by a PC, directly on the site
The front screen is Anti Glare, hence no reflection or reduction in brightness caused by the sun at any angle. Variable Message Sign Display or DMS is important equipment for monitoring and controlling system in both freeway and arterial road applications. These signs give the traffic management center a powerful tool to improve traffic flow on busy expressways by displaying varied message.
Policy of VARIABLE MESSAGE SIGN Messages
|· Effective Message Display
· VARIABLE MESSAGE SIGN Application
· Credible Message Display
· Message Display System
Variable Message Sign status displays must be designed to promote an easy interpretation and strategic understanding of system status. This is especially true when multiple operators may be responsible for variable message sign boards operations. Hence, the following requirements shall be adhered to.
· Automated Message Posting
The goal for a variable message sign management support system is to provide a fully automated message posting, with capability for the operator to modify messages after they are posted.
· Operator Message Posting and Control
Higher reliability is required when the automated support system uses operator verification data, and any additions or modifications to traffic flow data are required to be entered by the operator. Even with automated posting of variable message sign responses, the operators should maintain situation awareness of the status of variable message sign assets.
The operators must be provided with a resource map that shows the location and status of all sensors, cameras, variable message signs, and other TOC resources. It should indicate whether each variable message sign is currently in use. Before implementing a response plan for a specific incident, all related signs should be checked to ensure that they are not displaying an important earlier message for a different incident. On any status map of a divided highway, display unambiguously the direction of travel on which the incident is located.
· Interactive Message Posting System
Provide an easy way for the operator to modify or discontinue a variable message sign response plan or individual message that is no longer appropriate. To maintain public trust in the variable message sign system, messages must be timely and accurate. To support this requirement, modification or discontinuation of a message must be easy for the operator and thus reduce the possibility that this task will be “shed” during times of high workload. The approach shall be a computer interface in which a mouse “click” on a variable message sign on the map display would bring up a screen menu. This menu would provide, at a minimum, alternatives to “MODIFY” or to “DELETE” the message on that sign.
The visual display shall enable Main Roads staff to know at any time, what symbol is being displayed on the sign and, if required, to subsequently use this information in a court of law. This technology overcomes the problems of bulb changing associated with the halogen type signs as well as offering more flexible display options.