Driver Hours of Service, Fatigue, and Fitness for Duty
Hours of service
Passenger-carrier drivers operating across state lines follow federal hours-of-service limits: a maximum of 10 hours driving after 8 consecutive hours off duty, a 15-hour on-duty window, a 60-hour limit in 7 consecutive days or 70 hours in 8 days, and a required 30-minute break after 8 cumulative hours of driving without at least a 30-minute interruption. Carriers using the short-haul exception have different recordkeeping rules. California also imposes its own intrastate limits, so know which rules apply to your operation. Keep your log or electronic record current, and remember that falsifying records is a serious violation.
Fatigue
Fatigue impairs judgment and reaction time much like alcohol. Warning signs include drifting, heavy eyelids, yawning, and missing signs or exits. The only real remedy is rest - caffeine and cold air are temporary. Plan breaks, avoid driving in the circadian low hours, and get quality sleep before a trip.
Fitness for duty
You must be physically and mentally fit, free of impairing medication effects, and compliant with drug and alcohol rules. Report illness or injury that affects your ability to drive. Refuse to drive if you are too fatigued to be safe, and document the reason.
Traps
Questions test the 10-hour driving limit versus the 15-hour window, whether the 30-minute break counts as off-duty, and whether a driver may drive after 15 on-duty hours (no). Another trap is the idea that coffee overcomes fatigue.
Rule of thumb
When the limits or your body say stop, stop - rest is the only fix for fatigue.