Multifunctional systems in vehicles : a usability evaluation

Abstract

Car Human-Machine Interaction (HMI) is becoming increasingly complex as the extension of functionality necessitates new interface concepts. Various multifunctional systems operated by haptic rotary switches, touch screen, and voice control have been developed. A usability study of multifunctional systems available on the market was carried out to evaluate and compare different manual interaction principles. The systems used in the study were the BMW iDrive and the Audi MMI, both operated by a rotary switch, and the Jaguar touch screen interface. Firstly, a usability test was conducted where two naive and two trained participants tested each system during driving. Ten tasks, comprising CD, radio and navigation were solved by the participants. Secondly, six evaluators carried out a usability inspection, heuristic evaluation, to find possible problems in the systems. The results from the usability test indicated that the naive users interacted more rapidly with the touch screen interface. Trained users, on the other hand, had more even results over the systems. The problems found in the usability inspection gave explanations to some of the longer task times in the usability test.