Assessing Multifunction Interfaces in Vehicles

Abstract

The goal of this research was to determine whether system usability is requisite for system safety. To this end, the usability and safety of two multifunction in-vehicle interfaces were assessed to verify the hypothesis that the system scoring highest on usability testing would also score highest on safety testing. Two multifunctional systems were subjected to (a) heuristic evaluations to assess usability and (b) occlusion tests to assess safety. There were more heuristic violations, indicative of more usability problems, in System B relative to System A. Similarly, with regard to safety, results of occlusion testing showed that greater demands on time and visual resources were required to perform tasks when System B was used versus System A. Thus, the usability problems identified through heuristic evaluations represent possible precursors to the safety problems identified by occlusion tests. Given the latter and the fact that heuristic evaluations can be applied quickly and easily whereas occlusion testing can be costly and time-consuming, the results of the current research suggest that developers would benefit from correcting the usability limitations of a system before its safety performance is evaluated.