Table 1. Fatigue (VAS) scores after the last hour of driving (Mean±SD) and Karolinska Sleepiness Scale (KSS) scores before the last hour of driving (Mean±SD) in the reference session and in the 3 nocturnal driving sessions.

	Reference	Nocturnal driving sessions
		3–5 am	1–5 am	9 pm–5 am
Fatigue (VAS)	40.0 (±13.6)	65.1 * (±15.9)	66.8 * (±18.2)	75.0 * □ (±18.2)
KSS	2.6 (±1.2)	6.8 * (±1.8)	7.4 ** (±1.3)	8.0 ** (±1.4)

The asterisks refer to significant differences between the 3 nocturnal driving sessions (short, intermediate and long durations of driving) and the reference. The square refers to a significant difference between 9 pm–5 am and 1–5 am sessions.

^*P<.01.

^**P<.001.

^□P<.01.