Multi-Modal Menus And Traffic Interaction. Timing As A Crucial Factor For User Driven Mode Decision

Varieties of multi-modal menu outputs were examined in a real driving situation with respect to efficient system interaction and aspects of safety. An electronic manual served as an exemplary application. The speech output was combined with four different display-versions concerning the timing of the output. The test was based on a within-subject-design. Every subject performed one control condition ride and three rides with system interaction. The test revealed that if presenting the spoken and visual output simultaneously the subjects mainly used the display for menu selection. In consequence, the attention towards the traffic declined, which had a negative impact on the driving behavior. Presenting the visual output after the spoken output had ended, lead to much less influences on the driving behavior. However, the system interaction was as effective. Menu selection proved only problematic in the first system interaction ride. The process of acquiring strategies for spoken system interaction and its coordination with the traffic situation was rather straining.