Testing a Variable Message Sign (VMS) for NTCIP compliance is a way for organizations to confirm the communication and functional elements of the sign are working properly. Section 1203 of the NTCIP standard focuses on dynamic message signs and is the data dictionary that defines sign functionality.
A successful test should confirm that information is transferred from the central system to the sign and that the sign returns a response. Once the information reaches the sign, the test should evaluate the sign’s action from an operational perspective. Common items that are reviewed during the test include:
- Does the sign perform the action properly?
- Did the message display properly?
- Is the sign using the correct font?
- Is the text centered as directed?
How are tests performed?
Typically, a sample sign is set-up in a shop environment, or a manufacturer’s facility, along with test equipment that simulates different test scenarios. Testing software (such as Device Tester) records the results of each test administered as it relates to features, functionality, and formatting. The number of scenarios to be tested is substantial and can take up to a week to be fully tested against the standard.
Why test?
Testing variable message signs is critical to ensure NTCIP compliance. Thorough testing gives a manufacturer the confidence and validation needed to guarantee compliance with the NTCIP standard. From the DOT perspective, valid VMS testing decreases the likelihood of major issues when the system introduced into an ITS environment. When all parties are working from the same NTCIP standard, the deployment process is much smoother and fewer errors are detected.
NTCIP 1203
NTCIP 1203, the library that relates to dynamic message signs, has undergone three major revisions, with each version adding more features and functionality.
- Version 1, the initial standard, included the basic functionality to transfer a message to a sign, display the message on the actual sign and to receive information back from the sign. The standard included the brightness level of the sign, the adjustment of these levels, and the ability to set fonts.
- Version 2 added some additional functionality, but primarily dealt with graphics and color. Graphics could be displayed on the sign up to its full size and the number of colors from which to choose was in the thousands. It also allows for centering of text and image display and the ability to create “mini signs” within the main sign space.
- Version 3 added the ability to add formal test procedures. With more than 300 pages of formal test procedures, users can make their selection based on the features that need to be tested.
There is compatibility among versions of NTCIP between VMS signs. A Version 2 sign can successfully receive messages from a Version 1 control center; however, the combination would limit the functionality and features to whichever version is earlier. Upgrading to the newest version is ideal, but not required.
Delcan Technologies can help
Delcan Technologies, a Parsons company, is a world leader in the design and implementation of ITS systems and is involved in all stages of deployment as consultant, system developer and contractor. We provide support for manufacturers at any level. For more information on how we can assist you in your efforts, contact us here.
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