The effects of situational demands on gaze, speech and gesture input in the vehicle

Various on-the-road situations can make additional demands on the driver that go beyond the basic demands of driving. Thereby, they influence the appropriateness of in-vehicle input modalities to operate secondary tasks in the car. In this work, we assess the specific impacts of situational demands on gaze, gesture and speech input regarding driving performance, interaction efficiency and subjective ratings. An experiment with 29 participants in a driving simulator revealed significant interactions between situational demands and the input modality on secondary task completion times, perceived suitability and cognitive workload. Impairments were greatest when the situational demand addressed the same sensory channel as the used input modality. This was reflected differently in objective and subjective data depending on the used input modality. With this work, we explore the performance of natural input modalities across different situations and thereby support interaction designers that plan to integrate these modalities in automotive interaction concepts.