Driver Hours, Fatigue, and Fitness for Duty
Hours-of-service limits for passenger-carrying drivers differ from the property-carrying numbers, and the exam tests them directly.
The limits
49 CFR 395.5 allows 10 hours of driving after 8 consecutive hours off duty, within a 15-hour on-duty window that starts when you come on duty. You may not drive after 60 hours on duty in 7 consecutive days or 70 hours in 8 days. The 34-hour restart resets the cycle. Passenger carriers are not subject to the 30-minute break rule that applies to property-carrying drivers.
Records
Carry the record of duty status for the current day plus the previous 7 days, and use an ELD unless an exception applies. Record every change of duty status accurately; falsification is a serious violation.
Fatigue management
Sleep is the only real countermeasure. Plan 7 to 9 hours, respect the circadian low between 2 and 6 a.m., and recognize drifting, heavy eyes, missed signs, and yawning as warning signs. Caffeine postpones fatigue; it does not remove it. Rest before you are impaired.
Fitness for duty
You must be physically able to drive. Report illnesses and medications that affect alertness to your medical examiner and carrier, and do not drive drowsy.
Worked example
A driver comes on duty at 6 a.m., drives 4 hours, waits 3 hours, drives 4 hours, and finishes at 9:30 p.m. Total driving is 8 hours, inside the 10-hour limit. On-duty time is 15.5 hours, which exceeds the 15-hour window, so the final 30 minutes of driving is a violation even though the driving limit was respected.
Traps
Confusing the property limits (11 and 14) with passenger limits (10 and 15); counting only driving time; assuming a nap resets the 15-hour window.