This Standard covers electrically powered, on-road, variable message signs used for traffic management and/or driver information applications. Part 1 of the Standard covers ‘Fixed Signs’, where the display is mounted in a permanent position above or adjacent to the roadway. Part 2 of the Standard covers Portable Signs, where the display is mounted and deployed on a relocatable trailer.
While this Standard is based on systems that use the commonly available emitter, LED (Light Emitting Diodes), as the display source, the general criteria for driver observation, sign functionality and structural and operational integrity of the associated hardware are relevant for other forms of variable message signs. Relevant parts of this Standard can be applied to non-LED variable message signs. The Standard is not intended to exclude the use or development of alternative display sources.
