Non-driving-related tasks during level 3 automated driving phases–measuring what users will be likely to do.

Abstract

After activation of a Society of Automotive Engineers (SAE) Level 3 automated driving function (SAE International, 2021), the function takes over the driving task and the human user may engage in other, non-driving-related tasks (NDRTs). Meanwhile, the user needs to remain receptive to requests by the function because s/he needs to reengage in the driving task, when the function approaches a system limit and requests the user to take over. Hence, the effects of NDRT engagement on driver state and takeover behavior have been investigated closely. However, concerning relevance to traffic safety, it is important to take a step back and investigate what NDRTs users are likely to engage in, and what methods are suitable to collect respective data. Two experiments were conducted to answer these questions. In Experiment 1, participants experienced Level 3 automated driving in a Wizard-of-Oz vehicle on German motorways. After the ride, participants were asked to name NDRTs that they would engage in, if the function was available in their own vehicle. In Experiment 2, participants were asked to bring their own NDRTs along and experienced Level 3 automated driving in the Wizard-of-Oz vehicle. Comparison of results shows preferences of similar NDRTs (e.g., smartphone usage and reading). Moreover, we found that different methods provide different insights into NDRT engagement (i.e., engagement rate, total duration rate of engagement, and naming rate). Integrating our results in current literature landscape highlights the strong dependence of resulting NDRTs from the investigation method. Results, strengths, and weaknesses of the employed methods are discussed.

Impact of the driver’s visual engagement on situation awareness and takeover quality

“…During automated driving, participants were instructed to perform an NDRT. As Shi & Frey (2021) indicated that participants primarily wanted to engage in reading, the task consisted of reading aloud a text that scrolled automatically on the side tablet. The text was an excerpt of the story of Tom Sawyer.…”

“…In Level 3 automation, drivers may be on-the-loop if they supervise the road or out-the-loop if they are engaged in non-driving activities. Potential drivers of autonomous vehicles have been shown to want to perform new activities that require attentional resources such as reading, writing messages, eating, drinking, browsing the internet, or making phone calls (Pfleging et al 2016;Shi & Frey, 2021). Drivers can thus be expected to engage in non-driving activities that may divert their attention from the road (Naujoks et al, 2016).…”

Using Task Switching to Explain Effects of Non-Driving Related Activities on Takeover and Manual Driving Behavior Following Level 3 Automated Driving

“…Participants are instructed to engage in playing Tetris, reading a text and typing a summary of it, and watching a documentary film. These tasks are chosen because they are natural activities and likely to be performed when users have the choice [2,13]. Since these activities are applied in an experimental setting with instructions, they will be referred to as tasks in the following.…”