An Evaluation of the Ability of Drivers to Assimilate and Retain In-Vehicle Traffic Messages
Robert Graham Val A. MitchellHUSAT, Loughborough University, Leics., UK
The provision of weather, road, and traffic information to drivers via an in-vehicle system has potential benefits for both journey efficiency and traffic safety. Giving drivers advanced warnings of an event (where an event is defined as "any deviation from the normal traffic equilibrium state"; RDS-ALERT, 1990) can affect route choice and safety-related factors, such as driving speed. However, the success of such systems depends largely on the ability of drivers to assimilate, retain, and act on the information received. These processes rely on the application of ergonomics to the design of the system's man--machine interface (MMI). This chapter describes experiments evaluating various MMI aspects of a prototype in-vehicle system, and then makes recommendations accordingly.
The task of using a visually based in-vehicle information display can be broken down into a number of stages of information processing. Messages must first be detected, which involves the initial stimulation of vision, and recognized as familiar before being read and interpreted. The efficiency of this initial assimilation process (assimilation here refers to both visual and initial cognitive processing) may be affected by the layout, legibility, and complexity of the display. Some decision must then be made as to which elements of information are considered relevant. Finally, the relevant information is committed to memory until it must be acted on. The ability of drivers to recall traffic information depends on a number of factors, including the display complexity ( Labiale, 1989), the modality of message presentation ( Gatling, 1976), the length of messages ( Labiale, 1990), the