This literature review was initiated by the Nordic Meeting for Improved Road Equipment (NMF) as an updated supplement to the previous report “VMS — Variable Message Signs. A literature review” by Nygårdhs and Helmers, 2007. VMS can be used in a number of ways, for instance for information about speed, travel time, roadworks ahead, congestion, accidents, lane shift, weather, route guidance and events. During 2006—2009 a large number of studies regarding VMS have been completed, of which 61 are referred to in this report. The main results from these studies are: • Graphic-aided signs should be preferred to text signs. • The number of lines on a VMS should be kept to a minimum, with respect to comprehensibility. • Pictograms and messages must be evaluated before they are used in practice. • The typeface “Tern” is recommended for use within Europe. • Bilingual signs should be avoided. • A VMS activated only when speeding leads to reduced speed, i.e. better compliance. • Supplementary information to an activated VMS may not enhance behaviour concerning compliance. • Reading and processing a text message on a VMS lead to reduced speed. • The current speed limit is ignored if it is not motivated by the traffic situation, which means that the VMS should be activated only when conditions deteriorate. • It is essential that a VMS works correctly and reflects the actual conditions, which puts a high demand on equipment and central control. • Reading time is better correlated to the number of information units than to the number of lines. • A blank “off-screen” may enhance information processing when successive VMS are shown. • High luminance is preferable for symbols on VMS. • A three diode symbol thickness leads to better legibility than one or two diodes symbol thickness. Suggested areas of future research include graphic messages on VMS, legibility of VMS and information units. (Author/publisher) This report may be accessed by Internet users at http://www.vti.se/EPiBrowser/Publikationer%20-%20English/N12A-2011.pdf
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