Acoustic Cues Increase Situational Awareness in Accident Situations: A VR Car-Driving Study

Our work for the first time evaluates the effectiveness of visual and acoustic warning systems in an accident situation using a realistic, immersive driving simulation. In a first experiment, 70 participants were trained to complete a course at high speed. The course contained several forks where a wrong turn would lead to the car falling off a cliff and crashing – these forks were indicated either with a visual warning sign for a first, no-sound group or with a visual and auditory warning cue for a second, sound group. In a testing phase, right after the warning signals were given, trees suddenly fell on the road, leaving the (fatal) turn open. Importantly, in the no-sound group, 18 out of 35 people still chose this turn, whereas in the sound group only 5 out of 35 people did so – the added sound therefore had a large and significant increase in situational awareness. We found no other differences between the groups concerning age, physiological responses, or driving experience. In a second replication experiment, the setup was repeated with another 70 participants without emphasis on driving speed. Results fully confirmed the previous findings with 17 out of 35 people in the no-sound group versus only 6 out of 35 in the sound group choosing the turn to the cliff. With these two experiments using a one-shot design to avoid pre-meditation and testing naïve, rapid decision-making, we provide clear evidence for the advantage of visual-auditory in-vehicle warning systems for promoting situational awareness.

I. Introduction

Human errors constitute the most common reason for car accidents: based on the National Highway Traffic Safety Administration’s 2015 crash statistics report, 94 percent of all crashes are related to drivers’ errors. Importantly, 41 percent of these crashes involve some sort of attentional lapse or distraction of the driver [1]. Such distractions can originate both from in-vehicle or outside events. Concerning in-vehicle distractions, the use of mobile phones during driving is a considerable drain of attentional resources known to reduce, for example, braking speed [2] and to lead to overall poorer driving performance [3]. Similarly, one-time distractions coming from external stimuli also may cause the driver to withdraw attention from the driving task: this can, for example, be due to salient advertisements, the sudden appearance of animals [4], or even a small object on the road that can cause a critical accident if the driver focuses on avoiding the object rather than keeping track of nearby cars [5].