Visual Demand Evaluation Methods for In-Vehicle Interfaces

The primary aim of the research presented in this paper is developing a method for assessing the visual demand (distraction) afforded by in-vehicle information systems (IVIS). In this respect, two alternative methods are considered within the research. The occlusion technique evaluates IVIS tasks in interrupted vision conditions, predicting likely visual demand. However, the technique necessitates performance-focused user trials utilising robust prototypes, and consequently has limitations as an economic evaluation method. In contrast, the Keystroke Level Model (KLM) has long been viewed as a reliable and valid means of modelling human performance and making task time predictions, therefore not requiring empirical trials or a working prototype. The research includes four empirical studies in which an extended KLM was developed and subsequently validated as a means of predicting measures relevant to the occlusion protocol. Future work will develop the method further to widen its scope, introduce new measures, and link the technique to existing design practices.