How does fatigue at night differ from fatigue during the day for a commercial driver?

Pick an answer

1. Fatigue is identical at night and during the day with no difference at all
2. The body's natural drowsiness cycle makes fatigue set in more strongly at night, even on a normal schedule
3. Fatigue at night only affects drivers on their first overnight trip, not experienced ones, an assumption that doesn't hold up with driver
4. Fatigue only becomes a factor after driving more than 20 hours consecutively

Correct!

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