This is your brain on autopilot 2.0: The influence of practice on driver workload and engagement during on-road, partially automated driving
DOI: 10.1177/00187208231201054
archive: archived pipeline: cataloged verified
Summary
On-road study of 30 participants assessing how six weeks of practice with Level 2 partial automation (ACC + LKA) influences driver workload and engagement. Participants drove five Level-2 vehicles (Tesla Model 3/S, Cadillac CT6, Volvo XC90, Nissan Rogue) in Level 0 (manual) and Level 2 modes on two interstate highways differing in complexity (straighter I-15 vs. more curvy/mountainous I-80) across two testing sessions separated by a six-week daily-driving familiarization period. Driver cognitive state was measured behaviorally with the Detection Response Task (DRT, ISO 17488) and neurophysiologically via EEG frontal theta power (workload) and parietal alpha power (visual engagement). Manipulation checks confirmed DRT and EEG metrics were sensitive to driving demand. DRT RTs were slower under Level 2 than Level 0, slower on the more complex I-80, and faster at Session 2 than Session 1. A Level-of-Automation x Session interaction showed practice reduced Level-2 workload more than Level-0 workload, but only on the simpler I-15. Frontal theta showed no significant effects of automation, interstate, or session. Parietal alpha showed only a small main effect of interstate (lower alpha / more engagement on I-80). Authors conclude partial automation did not produce under-arousal or disengagement; if anything, supervisory monitoring imposed greater workload than manual control, with practice attenuating that cost in low-demand environments.
Key finding
Level 2 partial automation increased rather than decreased driver workload (slower DRT RTs vs. manual driving), and six weeks of daily practice reduced that workload only on the simpler highway (I-15), not on the more complex I-80. EEG frontal theta and parietal alpha showed null effects of automation level and session, indicating practice and automation effects appeared behaviorally but not neurally.
Methodology
On-road experiment, 2 (Level of Automation: 0 vs 2) x 2 (Interstate: I-15 vs I-80) x 2 (Session: pre vs post 6-week familiarization) within-subjects factorial design. N=30 drivers with no prior Level 2 experience and >=40 min round-trip highway commute. Five Level-2 production vehicles. Measures: DRT (ISO 17488) reaction time and hit rate; EEG frontal theta (Fz, 4-8 Hz) and parietal alpha (Pz, 8-12 Hz) power; auditory N-back and eyes-closed manipulation checks. Linear mixed-effects models predicted each dependent measure. Six-week familiarization required daily partial-automation driving on participant's commute, verified by in-vehicle camera.
Sample size: N=30 (12 female, 18 male; M_age=35.73, SD=9.34)
Quality score: 5 / 5