CIE 111-1994

This technical report draws together research findings and practical experience of the visual performance of variable message signs which might affect their use in road traffic management. Variable message signs are divided into three categories of light emitting, light reflecting and hybrid signs. The qualities of the observer and the sign which might affect the sign's performance are discussed together with practical issues concerned with the installation of the sign. Light emitting signs and light reflecting signs are then discussed in detail and some views are presented as to how the visual performance of the signs can be maximised.

The use of variable message signs has increased due to increased public demand for uptodate information. The most flexible of the variable message signs use a matrix format upon which characters and symbols are formed by showing appropriate patterns of matrix elements. The use and siting of a variable message sign have requirements different to that of a conventional sign. Despite the increase in the use of variable message signs there are no clear guidelines for their design. The objective of this report is to gather the information base about the application of such signs to provide a sound background for their future application.

The report is written in English, with a short summary in English, French and German. It contains 60 pages, with 13 figures and 11 tables.