Hours of service on the CDL knowledge test

Three limits, not one

The federal hours of service rules in 49 CFR Part 395 set separate limits, and test questions turn on which one applies. Confusing them is the most common way to miss these questions.

Drivers carrying property

• 11 hours of driving after 10 consecutive hours off duty.
• The 14-hour window. No driving after the 14th hour from coming on duty, even if some of that time was not driving.
• A 30-minute break once 8 hours of driving have built up.
• 60 hours in 7 days, or 70 in 8. These cap ON-DUTY time, not just driving. Loading, fueling and paperwork count.

Drivers carrying passengers

A bus driver works to different numbers: 10 hours of driving after 8 consecutive hours off duty, and no driving after 15 hours on duty. The weekly 60 and 70 hour caps apply as well. A question about a bus is answered from these limits, not the truck ones.

How the questions catch people

• Treating the 14-hour window as 14 hours of driving. It is a window on the clock, and breaks do not extend it.
• Applying the weekly cap to driving only, when it counts all on-duty time.
• Answering a passenger question with property-carrying limits.

A way to answer them

First ask whether the driver carries property or passengers. Then ask whether the question is about driving time, the daily window, or the weekly total. Each has its own number, and the scenario usually gives you what you need to tell which.