Anticipatory Driving in Automated Vehicles: The Effects of Driving Experience and Distraction

Abstract

Objective: To understand the influence of driving experience and distraction on drivers' anticipation of upcoming traffic events in automated vehicles.

Background: In nonautomated vehicles, experienced drivers spend more time looking at cues that indicate upcoming traffic events compared with novices, and distracted drivers spend less time looking at these cues compared with nondistracted drivers. Further, pre-event actions (i.e., proactive control actions prior to traffic events) are more prevalent among experienced drivers and nondistracted drivers. However, there is a research gap on the combined effects of experience and distraction on driver anticipation in automated vehicles.

Methods: A simulator experiment was conducted with 16 experienced and 16 novice drivers in a vehicle equipped with adaptive cruise control and lane-keeping assist systems (resulting in SAE Level 2 driving automation). Half of the participants in each experience group were provided with a self-paced primarily visual-manual secondary task.

Results: Drivers with the task spent less time looking at cues and were less likely to perform anticipatory driving behaviors (i.e., pre-event actions or preparation for pre-event actions such as hovering fingers over the automation disengage button). Experienced drivers exhibited more anticipatory driving behaviors, but their attention toward the cues was similar to novices for both task conditions.

Conclusion: In line with nonautomated vehicle research, in automated vehicles, secondary task engagement impedes anticipation while driving experience facilitates anticipation.

Application: Though Level 2 automation can relieve drivers of manually controlling the vehicle and allow engagement in distractions, visual-manual distraction engagement can impede anticipatory driving and should be restricted.

Keywords: anticipatory driving; driver distraction; driving automation; driving simulator; visual attention.

Figure 1

(a) NADS MiniSim driving simulator; (b) screenshot of the secondary task.

Figure 2

Boxplots of glances at anticipatory cues and the secondary task display. Boxplots present the five-number summary, along with the mean depicted through a hollow diamond. The mean (M) and standard deviation (SD) values are also provided at the top of each plot.

Figure 3

(a) Visualization of anticipatory driving behaviors at the scenario level: the number of scenarios where an anticipatory driving behavior was observed. The number of scenarios under each experimental condition is 32 with four scenarios per participant and eight participants within each condition, representing the maximum value for the y-axis. Pre-event preparation counts are based on scenarios with only a pre-event preparation (no pre-event action); pre-event action counts include any scenario with a pre-event action, including those that were preceded by pre-event preparation. (b) Visualization of anticipatory driving behaviors at the participant level: the number of participants who displayed anticipatory driving behaviors (pre-event action or preparation) in 0, 1, 2, 3, or 4 scenarios within each experimental condition. The number of scenarios is indicated using a color gradient with darker shades corresponding to more scenarios with anticipatory driving behaviors.

Figure 4

Average timing of participants’ responses relative to event onset in different experimental conditions. If participants exhibited multiple responses (e.g., pre-event preparation followed by postevent action), the timing of the first response was used (pre-event preparation in the example). On the y-axis, event onset corresponds to 0. Negative values represent responses before event onset and positive values represent responses after event onset. Numbers in brackets represent the number of scenarios where each behavior was exhibited as the first response (maximum is 32: 4 scenarios × 8 participants). N/A: timing information not available as there are no responses of the corresponding type.

Figure 5

Boxplots of glances at the secondary task display for drives with and without anticipatory driving behaviors, by cue-onset. Boxplots present the five-number summary, along with the mean depicted through a hollow diamond. The mean (M) and standard deviation (SD) values are also provided at the top of each plot.