Graphical route information on variable message signs

Reports on experiments in the Netherlands on the use of graphical route information panels (GRIP) as part of variable message systems (VMS) providing information to drivers. GRIP appear to be as safe as regular VMS. Digestion of the information presented is initially quicker for regular VMS, but motorists get used to GRIP rapidly and the difference is made up quickly. Good map readers digest graphical information more quickly than poor map readers. Route choices are better with GRIP than with regular VMS. Good map readers make on average better route choices than poor map readers. Graphical information, if properly understood, leads to better route choices. There are reasons to assume that the limit to the amount of information per GRIP was reached in this experiment in one particular condition. This manifested itself in the instant digestion of information and in poor quality of the route choice. GRIP also show a rapid development in subjective reactions (preference, comprehension), resulting in a rapid decrease of the original advantage of regular VMS. Subjective reactions also show clear differences between good and poor map readers