Exploring the effectiveness of a digital voice assistant to maintain driver alertness in partially automated vehicles

Abstract

Objective: Vehicle automation shifts the driver's role from active operator to passive observer at the potential cost of degrading their alertness. This study investigated the role of an in-vehicle voice-based assistant (VA; conversing about traffic/road environment) to counter the disengaging and fatiguing effects of automation. Method: Twenty-four participants undertook two drives-with and without VA in a partially automated vehicle. Participants were subsequently categorized into high and low participation groups (based on their proportion of vocal exchanges with VA). The effectiveness of VA was assessed based on driver alertness measured using Karolinska Sleepiness Scale (KSS), eye-based sleepiness indicators and glance behavior, NASA-TLX workload rating and time to gain motor readiness in response to take-over request and performance rating made by the drivers. Results: Paired samples t-tests comparison of alertness measures across the two drives were conducted. Lower KSS rating, larger pupil diameter, higher glances (rear-mirror, roadside vehicles and signals in the drive with VA) and higher feedback ratings of VA indicated the efficiency of VA in improving driver alertness during automation. However, there was no significant difference in alertness or glance behavior between the driver groups (high and low-PR), although the time to resume steering control was significantly lower in the higher engagement group. Conclusion:The study successfully demonstrated the advantages of using a voice assistant (VA) to counter these effects of passive fatigue, for example, by reducing the time to gain motor-readiness following a TOR. The findings show that despite the low engagement in spoken conversation, active listening also positively influenced driver alertness and awareness during the drive in an automated vehicle.

How to Counteract Driver Fatigue during Conditional Automated Driving—A Systematic Review

“…A significant difference was found on the KSS, indicating that playing Tetris led to a lower fatigue level than no NDRA. This was confirmed by the analysis of PERCLOS and the expert rating by Wiegand et al [36]. Moreover, takeover performance was assessed by takeover time, time-to-collision, and maximum lateral and longitudinal acceleration, though no significant differences were found between Tetris and no NDRA.…”

“…The authors showed lower subjective fatigue ratings on the Karolinska Sleepiness Scale (KSS) created by Åkerstedt and Gillberg [37] and higher pupil diameter, indicating higher alertness in the drive with a speech-based assistant. Thus, fatigue symptoms were reduced with assistants, but cognitive workload was higher when driving with a speech-based assistant [36]. Moreover, no drivers nodded off when driving with a speech-based assistant, while six nodded off when driving without one.…”

“…A simulator study by Mahajan et al [36] examined the effectiveness of speech-based assistants during CAD to counter the effects of passive fatigue. Mahajan et al [36] used a speech-based assistant with natural language interactions and compared it to driving without a conversation with a speech-based assistant.…”

“…A simulator study by Mahajan et al [36] examined the effectiveness of speech-based assistants during CAD to counter the effects of passive fatigue. Mahajan et al [36] used a speech-based assistant with natural language interactions and compared it to driving without a conversation with a speech-based assistant. The assistant initiated a conversation every 3 min by asking a question or providing information, e.g., event reminders (calendar), entertainment, or road traffic feedback.…”

Diurnal effects of dynamic lighting on alertness, cognition, and mood of mentally fatigued individuals in a daylight deprived environment

“…The PVT is a simple sustained attention task that measures objective alertness by assessing the reaction speed of the brain to external sensory stimuli. 41 To eliminate the intervention effects of the acoustic environment on fatigue, 42 a 5-minute visual version of PVT was employed with a red dot randomly appearing at the centre of the computer screen (Interstimulus Interval (ISI): 2000–10 000 ms). The participants were asked to keep their index finger on the space key and press it as soon as they see a red dot (Figure 4(a)).…”