Automotive HUDs: the overlooked safety issues.

The transfer of tactical aviation technology into automobiles is creating information display requirements that are likely to be met by use of the head-up display (HUD). These developments are based largely on conclusions that the HUD-related safety issues raised in the aviation HUD literature can be dismissed and that the benefits of using HUDs are certain. Such conclusions either neglect relevant research or are supported by a very small amount of evidence, much of which is either irrelevant or generated within a flawed methodological paradigm. This critical review covers the issues of (a) HUD focal distance and its effect on the perception of outside objects and (b) the effects of HUD imagery on visual attention. The issues of focal distance, cognitive capture, and the inherent connection between the two may have a greater impact on safety in the automotive context than they do in aviation.