optimization; this is particularly important for the distance representation and the content/structure of voice messages.
All three route guidance systems resulted in significant eyes-off-the-road time. However, the difficulty lies in deciding what constitutes "unacceptable" or "unsafe" behavior. The techniques introduced here have attempted to address this by adding context to visual behavior, thus aiding in the examination of systems in terms of potential safety-related issues.
As an example, there is some evidence that, for high visual demand situations, a moving map-based system results in increased steeling wheel variability, which indicates that subjects were wavering within their lanes. However, this result was not conclusive and more controlled research is required to test this hypothesis fully.
It was clear that, for particular maneuvers, the information presented by the symbol-based systems (especially S1) was too late. Furthermore, it is clear that the resulting driving behavior has strong implications for driver safety. However, it is impossible, based on the results of this analysis, to be sure what the optimum timing of route guidance messages is. Even in the system conditions, where no obvious unsafe driving occurred, drivers did not indicate or change lanes as early as for the "ideal" (i.e., the Instructions condition). Again, further research is needed to determine guidelines for the timing of route guidance messages.
This work was carried out as part of the Basic Research in Man-Machine Interaction (BRIMMI) project, conducted within the EUREKA-supported PROMETHEUS program. It was supported in part by the U.K. Department of Trade and Industry and the motor manufacturing partner was the Ford Motor Company Limited.
Alm H. ( 1990). Drivers' cognitive models of routes. DRIVE 2 Project V1041 (GIDS), Contribution to deliverable GIDS/NAV2. Linköping, Sweden: VTI.
Ashby M., Fairclough S. H., & Parkes A. M. ( 1991). A comparison of two route information systems in a urban environment. DRIVE 1 Project V1017 (BERTIE), Report no. 47. Loughborough, UK: HUSAT Research Institute.
Barrow K. ( 1990). Human factors issues surrounding the implementation of in-vehicle Navigation and Information systems (SAE Tech. paper 910870).
Bengler K., Haller R., & Zimmer A. ( 1994). Experimental optimisation of route guidance information using context information, "Towards an Intelligent Transport System," Proceedings of the First World Congress on Applications of Transport and Intelligent Vehicle-Highway Systems, 4, 1758-1765.