Exploring the benefits of conversing with a digital voice assistant during automated driving: A parametric duration model of takeover time. (July 2021)

• Record Type: Journal Article
• Authors: Mahajan, Kirti; Large, David R.; Burnett, Gary; Velaga, Nagendra R.
• Is Part Of: Transportation research. Volume 80(2021)
• Page Start: 104
• Page End: 126
• Publication Date: 2021-07
• Subjects: Human-machine-interfaces -- Voice-user interfaces (VUI) -- Conditional automation -- SAE level 3 -- Passive fatigue -- Driver takeover; Automobile drivers -- Psychology -- Periodicals; Automobile driving -- Psychological aspects -- Periodicals; Transportation -- Psychological aspects -- Periodicals; 629.283019
• DOI: 10.1016/j.trf.2021.03.012
• Languages: English
• ISSNs: 1369-8478

Abstract

Highlights: Conversing with voice assistant (VA) increased driver alertness in automated vehicles (AVs). Verbal traffic cues can redirect visual attention to road environment in AVs. VA could assist the drivers in takeover, building appropriate situation awareness. VA increased the probability of making a timely (safe and aware) takeover by 39%. Abstract: Vehicle automation allows drivers to disengage from driving causing a potential decline in their alertness. One of the major challenges of highly automated vehicles is to ensure a timely (with respect to safety and situation awareness) takeover in such conditions. For this purpose, the current study investigated the role of an in-vehicle digital voice-assistant (VA) in conditionally automated vehicles, offering spoken discourse relating specifically to contextual factors, such as the traffic situation and road environment. The study involved twenty-four participants, each taking two drives (counterbalanced): with VA and without VA, in a driving simulator. Participants were required to takeover vehicle control following the issuance of a takeover request (TOR) near the end of each drive. A parametric duration model was adopted to find the key factors determining takeover time (TOT). Paired comparisons showed higher alertness and higher active workload (mean NASA-TLX rating) during automation when accompanied by the VA. Paired t -test comparison of gaze behavior prior to takeover showed significantly higher instances of checking traffic signal, roadside objects, and the roadway during the drive with VA, indicating higher situation awareness. The parametric model indicated that the VA increased the likelihood of making a timely takeover by 39%. There was also some evidence suggesting that male drivers are likely to resume control 1.21 times earlier than female drivers. The study findings highlight the benefits of adopting a digital voice assistant to keep the drivers alert and aware about the recent traffic environment in partially automated vehicles.