Figure 2

Self-reported sleepiness following the manually controlled and self-driving conditions for each study. Higher Karolinska Sleepiness Scale (KSS) scores indicate higher sleepiness. For each box, the solid white line indicates the median, the dashed white line indicates the mean, and the bottom and top boundaries of the box indicate the 25th and 75th percentiles, respectively. The bottom and top whiskers indicate the 10th and 90th percentiles, respectively (Study 1 n = 17; Study 2 n = 19; Study 3 n = 19). * = p < .05.