This report describes a simulator experiment into the effects of combining different kinds of information on motorways. It deals, in particular, with the effects on driver information intake that may occur as a consequence of combining. The components in the combinations were Dynamic Route Information Panels (DRIPs), section control panels, and the static guide signs. The combinations investigated comprised those in which components were simply added on top of each other as well as combinations in which the combined design anticipated upon the possible effects of driver overload. Performance was assessed in terms of responses to the combined signs (decisiondistances, `times-to-sign'), and in terms of behavioural parameters (speed and lateral position variability, proportion of short headways). Combining signs resulted in negative effects on information intake. There were also indications of a negative effect on driving performance in some combinations. Negative effects were, however, to some degree compensated for: (1) by adding a red rim as a `marker' to the section control panels; and (2) by integrating the dynamic information of the DRIPs within the static guide signs. In all, the negative effects of combining, particularly when ameliorated by the modifications to the combined design, were not as such to qualify performance as unacceptable. (A) See also IRRD 898626.
Samenvatting