Continuously displayed information involving status is best devoted to text presentations on a video screen and often as an alphanumeric display of low textual density. Intermittent information that is complex should be displayed graphically (when practical) with a textual explanation. As the intermittent information becomes simplified, the use of tones with icons or even tones alone should be considered.
These recommendations are general guidelines that do not apply to every information item present in an ATIS system. Thus, the guidelines must be applied with care, particularly when an individual requirement differs from the general trend of the rest of the requirements within a functional grouping. For example, in isolated instances, a route planning information item specifies an in-transit drive mode. The normal trip status for route planning is predrive. As a result, the decision aid was developed without the consideration of the safety criteria associated with motion of the vehicle, so adjustment in the decision aid (i.e., adding safety criteria) and recommended display format may be necessary.
Note that the guidelines often include highly functional ATIS systems for which both visual overload (due to safety) and auditory annoyance (due to frequency of potential messages) are of primary concern. In a lower functionality system, both of these concerns, as well as some of the trip status allocation issues, are less critical.
During predrive trip status, the sensory modality that the allocation tool selects is split between visual-only presentations and visual and auditory combinations. The complexity of information being presented is the key to this difference. Because the hazards of visual distraction and workload have been removed, there is little reason to limit the use of visual-only information. In route planning situations, some spatial relations between current location and desired destination are simply easier to show on a map than to explain in a verbal message. It is reasonable to plan a route before departure anyway, so the need to program the vehicle while stationary is not really a disadvantage. The visual component used in route planning is not always a map. On the contrary, text was frequently recommended to describe locations. There are a number of information items that are too specific to be handled by a graphic alone. In addition, a written explanation often helps users who are not spatially adept to plan and execute routes.
Once the destination has been determined and the driver begins the journey, the use of visual displays with no supplemental auditory information decreases in frequency. Because the driver must now devote a large amount of visual attention to driving, as well as vehicle navigation and guidance, the