Hours of Service, Fatigue, and Fitness for Duty
What the exam tests
You need the passenger-carrying hours-of-service limits and the fitness rules that keep an impaired or exhausted driver out of the seat.
Core rules
- For passenger-carrying CMVs: 10 hours driving after 8 consecutive hours off duty; 15-hour on-duty window; 60 hours in 7 days or 70 hours in 8 days. A 34-hour restart resets the weekly cycle.
- ELD use is required unless a specific exception applies. Keep records current and accurate.
- Do not drive under the influence of alcohol, marijuana, controlled substances, or impairing medication. Refuse testing only at the risk of disqualification.
- Fatigue is a hazard: get sleep before duty, take breaks, and do not rely on caffeine to overcome drowsiness. You must be medically certified and self-certify your operating category.
- Report any condition that affects your ability to drive safely.
Worked example
A driver came on duty at 05:00, drove 6 hours, took a 1-hour break, and then drove 3.5 more hours. By 20:00 the driver has been on duty 15 hours; the 15-hour window is exhausted. The driver cannot continue driving even though only 9.5 driving hours were used.
Traps
Confusing the property-carrier 11-hour driving limit with the passenger 10-hour limit. Counting only driving time and ignoring the 15-hour window. Assuming a break extends the 15-hour window. Driving while drowsy because the schedule is tight.