Hours of Service
The federal limits on driving and on-duty time, and the records that prove you complied.
Endorsement: General Knowledge · Source: FMCSA CDL Manual (public domain)
Hours-of-service rules under 49 CFR Part 395 cap how long you can drive and be on duty, and the General Knowledge exam tests them in detail. For property-carrying CDL drivers, the limits are: 11 hours of driving after 10 consecutive hours off duty; a 14-hour on-duty window from when you first go on duty (you cannot drive after the 14th hour even if you took breaks); a required 30-minute break before driving more than 8 cumulative hours; and a 60-hour-in-7-days or 70-hour-in-8-days limit reset by 34 consecutive hours off duty.
For passenger-carrying drivers, the limits are 10 hours driving after 8 consecutive hours off duty, a 15-hour on-duty window, and the same weekly limits. The split-sleeper provision lets property drivers split required off-duty time into two periods totaling 10 hours, with one period of at least 7 consecutive hours in the sleeper berth and another of at least 2 consecutive hours either off-duty or in the sleeper.
Electronic Logging Devices (ELDs) are required for nearly all commercial drivers under federal rule, replacing paper logbooks for most operations. Drivers must be able to produce ELD records on demand at roadside inspections and must know how to operate the device, transfer records, and annotate corrections. Falsifying logs is a serious violation that can result in driver disqualification and significant fines for both driver and carrier. The Manual lists specific exemptions including the short-haul exemption (operating within a 150-air-mile radius and returning to the same location within 14 hours), and exam questions frequently test which scenarios qualify.
Key terms to memorize
- GVWR
- GCWR
- CDL
- CLP
- medical examiner's certificate
- reasonable suspicion
- hours of service
Other General Knowledge topics
- Pre-Trip Inspection — A systematic seven-step pre-trip walk-around to catch defects before they put you and the public at risk.
- Basic Vehicle Control — Backing, turning, and low-speed maneuvering safely with a vehicle whose blind spots are larger than most cars are long.
- Hazard Perception — Reading the road, recognizing developing problems, and acting before they become emergencies.
- Emergency Maneuvers — Braking, steering, and skid control when something goes wrong.
Test what you learned
Now that you have the Hours of Service material in your head, drill the General Knowledge practice test. The questions are drawn from the same FMCSA source material this article paraphrases. For state-specific framing, jump to your state page and pick the General Knowledge test for your jurisdiction.