Nordiskt samarbetsprojekt inom NMF: synbarhet av VMS
2006 (Swedish)Report (Other academic)
In recent years, VMS (Variable Message Signs) have been used more frequently in Nordic countries. The VMS should fulfil the requirements given in the standard EN 12966-1, with respect to symbol luminance, luminance contrast, colour and beam width. This study has primarily investigated which symbol luminances are suitable from the road-user's point of view, i.e. luminances which make the sign conspicuous, but not as high as to involve glare and thereby impair legibility. In fact, the study includes three observation occasions, At the third occasion, comparative observations of two variable message signs with white symbols placed next to each other were made. The report mainly deals with this latter observation study. At the assessments, three observers (the authors) had to decide which symbol luminance they found "most suitable". This implied that the three observers compared the two signs, which always had different luminance, with respect to "suitable symbol luminance" and through a series of comparisons the preferred luminance was defined. This was done through observations at a distance of 46 metres from the signs during various light conditions, in daylight, dawn and darkness. The results show that to obtain the luminances that were considered "most suitable", the VMS had to belong to luminance class L3. If the correlation in the standard between luminance and illuminance would be based on this "suitability measure", this result would be true for all lighting conditions. However, there was a tendency that in darkness, it was also possible for a sign belonging to class L2 to fulfil the demand for symbol luminance. Daylight conditions became standardizing, though, and under these lighting conditions luminances in class L3 were preferred. A comparison of the results from the three observation occasions shows great concordance: A predominant amount of observations show that luminance class L3 is demanded for achieving "suitable" luminance. However, there are also indications that luminances belonging to class L2 could be accepted, but from the road-user's point of view, L3 is still preferred.
Place, publisher, year, edition, pages
Linköping: VTI., VTI notat 20-2006 , 2006. , 31 p.
Variable message sign, Visibility, Luminance, Observation, Daylight, Night
Research subject Road: Traffic engineering, Road: Traffic control and traffic information
IdentifiersURN: urn:nbn:se:vti:diva-1598OAI: oai:DiVA.org:vti-1598DiVA: diva2:670310