Subjective Evaluation of Road Situation Alerts Using Visual, Speech and Auditory Modalities with Elderly Drivers

Abstract

Drivers often rely on navigation systems and traffic alerts to anticipate the road events ahead, such as obstacles, accidents, and roadworks. We designed simple road situation alerts using visual, speech, and auditory modalities to warn drivers about upcoming road events. The prototype was tested with a driving simulator and evaluated with elderly drivers. In this study, we evaluated drivers’ subjective trust, cognitive workload, and situational awareness in three experimental conditions. We also collected electrocardiograms to measure the workload and stress as a response to the stimuli. Results show that visual warnings were difficult to notice and distractive. Speech and sound combination resulted in the lowest cognitive load, highest trust while maintaining the highest situational awareness. Both speech and visual warnings reduced distrust compared to the baseline. The weather did not affect any of the subjective measures. The physiological analysis showed that visual warnings induce lower stress compared to speech warning alerts. Speech alerts enabled the highest situational awareness.