This is the report on a study commissioned by VIC ROADS to establish the minimum photometric and optical standards for Variable Message Signs (VMS) used in the road environment. There were three field trials. The first two investigated minimum photometric requirements to ensure VMS legibility in daylight and at night. A total of 54 different VMS conditions were evaluated, by varying luminous intensity, pixel spacing, colour, pixel shape, fill-factor, single and double-stroking for each of four generic types of VMS (optical fibre, LED, reflective flip pixel and internally illuminated displays). The third field trial examined the sequence of messages. Reflective pixel displays performed poorly in both day and night conditions. Internally illuminated displays were the most legible during daylight, and green LED at night. The relative performance of the various combinations is discussed in the report. The sequencing experiment showed that the total message line must be no greater than 0.67% (and preferably only 0.5%) of the 'legibility time'. This work should contribute to an uniform approach to specifying the minimum photometric requirements of VMS. The ISBN of the microfiche version is 0-86910-529-9.
Samenvatting