How many hours can a commercial truck driver drive before taking a mandatory break?

What the Law Says

Federal regulations governing commercial truck driver hours of service (HOS) are established under the authority of the Motor Carrier Safety Act and implemented by the Federal Motor Carrier Safety Administration (FMCSA). While 49 U.S.C. § 31101 provides definitions, the specific HOS limits are codified in FMCSA regulations at 49 C.F.R. Part 395 — which derive their statutory authority from 49 U.S.C. §§ 31136 and 31502. Although § 31101 itself does not set hour limits, it defines key terms like 'commercial motor vehicle' and 'motor carrier', forming the foundation for enforceable safety rules.

The core driving limits are: drivers may drive no more than 11 hours during a 14-hour on-duty period, following at least 10 consecutive hours off duty. Within that 14-hour window, a driver must take a 30-minute break after accumulating 8 hours of driving time.

These rules aim to prevent fatigue-related crashes by ensuring drivers have adequate rest and regular breaks. The 14-hour 'on-duty' clock starts when any work begins and cannot be extended — even with off-duty time taken within it (except for sleeper berth provisions).

Statutory Text

In this part—'commercial motor vehicle' means a motor vehicle or combination of motor vehicles used in commerce to transport passengers or property if the motor vehicle—(A) has a gross vehicle weight rating or gross combination weight rating, or gross vehicle weight or gross combination weight, of 10,001 pounds or more; (B) is designed or used to transport more than 8 passengers (including the driver) for compensation; (C) is designed or used to transport more than 15 passengers (including the driver) and is not used to transport passengers for compensation; or (D) is used in transporting hazardous materials requiring placarding under regulations prescribed by the Secretary.

— 49 U.S.C. § 31101 — Definitions

What to Do

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