Figure 2. Dashcam video images and frequency of microsleep-related behaviors in case 2.

Case 2: (A) Dashcam video footage recorded immediately before the collision. (1) Dashcam video footage from outside the vehicle showed that the vehicle was approaching the median poles with the right lane departure. (2) Dashcam video footage from inside the vehicle showed that the driver’s eyes were closed and body movements were absent. (B) Appearance of microsleep-related behaviors by analyzing every second of interior dashcam video footage for 3 minutes after the start of driving. (C) Appearance of microsleep-related behaviors by analyzing every second of exterior dashcam video footage for 3 minutes before the collision. The frequency of microsleep-related behaviors for 3 minutes before the collision was clearly greater than that immediately after the start of driving. The horizontal axes of (B) and (C) represent the time in seconds (s) from 0 to 180 seconds immediately after the start of driving in (B) and from 180 to 0 seconds before the collision in (C). The vertical axes of (B) and (C) represent the number of occurrences (n) of each behavior.