Out-of-Domain Spoken Dialogs in the Car: A WoZ Study

Mobile Internet access via smartphones puts demands on in-car infotainment sys-tems, as more and more drivers like to ac-cess the Internet while driving. Spoken dialog systems (SDS) distract drivers less than visual/haptic-based dialog systems. However, in conversational SDSs drivers might speak utterances which are not in the domain of the SDS and thus cannot be understood. In a Wizard of Oz study, we evaluate the effects of out-of-domain utterances on cognitive load, driving per-formance, and usability. The results show that an SDS which reacts as expected by the driver, is a good approach to control in-car infotainment systems, whereas unex-pected SDS reactions might cause severe accidents. We evaluate how a dialog initia-tive switch, which guides the user and en-ables him to reach his task goal, performs.