A laboratory experiment which compared responses to two layouts of advance road direction signs is described. American 'list' type and complex junction signs were European 'map' type and complex junction signs were European 'map' type. Observers made directional responses to the signs, briefly flashed on a screen to their left, and at the same time performed a central tracking task as a substitute for driving. The response times to the signs and 'distraction scores' from the central task were measured. The time taken to respond to either layout was the same and it appeared possible to respond to the mixed signs with the same facility as to the distraction scores but the method of measuring the distraction is not considered reliable. Previous research has suggested that there are advantages in displaying- mixed signs: the 'list' signs giving advance directions at simple junctions provide optimum visibility for a given display area although advance 'map' signs may be required at complex intersections. The experiment provides supporting evidence for this suggestion, as the mixed layout does not appear to lead to difficulty of interpreting the directional information.
Abstract