Investigating screen complexity in the vehicle, how does design effect driver attention and task performance?

Digital systems can encourage information overload, and the driving environment is not immune to this. In-vehicle displays are increasing in functional and informational complexity, which can lead to increased workload if not designed appropriately for the dynamic driving environment. This is because drivers balance attentional resources across multiple activities, including driving and non-driving related activities - this is known as ‘attention management’. Poor display design can lead to difficulties in appropriate attention management. Three important factors in display design that influence usability are (1) Layout : how displayed content is positioned, (2) Breadth: how much content is located on each screen, and (3) Depth: or how many layers are contained within the system. Variations in Layout, Breadth and Depth were assessed using a driving simulator where two task performance measures indexed the impact of variation in display design. The use of different layouts influenced how drivers managed their attention. Increasing amounts of on-screen content negatively affected task performance measures. For low levels of information, breadth outperformed depth, but as content levels increased, depth mitigated the impact of high content levels, but avoiding user errors becomes challenging. These results have implications for contextual display design in reducing the demand on driver attention and making in-vehicle systems appropriate for use. • Display layout impacts task performance in a driving simulator • As information content increases on a single in-vehicle display screen, task performance decreases • For low information content levels, there are task performance advantages to using breadth • For higher information content, there are task performance advantages to using depth