Hours of Service and Fatigue
Hours of Service and Fatigue tests the limits that govern your day and the fatigue signs that make those limits matter. Know the numbers cold, then apply them to a timeline.
The limits
- 11-hour driving limit after 10 consecutive hours off duty.
- 14-hour on-duty window; you cannot drive after it ends, even if you have driving time left.
- 30-minute break after 8 cumulative hours of driving.
- 60 hours in 7 days or 70 hours in 8 days; a 34-hour restart resets the cycle.
- Sleeper-berth split: 8 hours in the sleeper plus 2 hours off duty can satisfy the 10-hour reset.
Fatigue
Fatigue impairs judgment before you feel sleepy. Warning signs include drifting, missed exits, heavy eyes, and irritability. Stop, rest, or swap drivers; caffeine and open windows are temporary fixes, not solutions.
Worked example
You start at 6:00 a.m. and drive 4 hours, take a 1-hour break, drive 4 more hours, then take the required 30-minute break at 2:00 p.m. The 14-hour window ends at 8:00 p.m. You have used 8 driving hours, so 3 driving hours remain-but only until 8:00 p.m. If you are still 90 minutes from the terminal at 7:30 p.m., you have 30 minutes of legal driving time, not 90.
Traps
Confusing the 11-hour driving limit with the 14-hour window; forgetting the 30-minute break; counting on-duty time as off-duty; and treating a restart as automatic without 34 consecutive hours off.