Hours of Service in Commercial Trucking: Rules, Limits, and Permitted Exceptions

Hours of Service, or HOS, is a set of federal rules that govern driving time and required rest periods for commercial drivers. The Federal Motor Carrier Safety Administration (FMCSA) requires most drivers operating commercial motor vehicles in interstate commerce to follow these regulations.

The rules are designed to reduce the risk of fatigue-related crashes by setting consistent limits on driving and working hours. They also establish common operating requirements across the trucking industry, helping carriers and drivers follow the same federal standards.

What Are Hours of Service Regulations?

Hours of Service (HOS) regulations are federal rules that limit how long a commercial driver may drive and work before taking required rest. Set by FMCSA at 49 CFR Part 395, they apply to most commercial motor vehicle drivers operating in interstate commerce.

The rules apply to most drivers of commercial motor vehicles used in interstate commerce—that is, freight or passengers crossing state lines. Drivers who operate only within a single state (intrastate) follow their state's rules, which are often similar but set by the state. These requirements are established and enforced by FMCSA as part of the federal safety regulations governing commercial motor vehicle operations.

Core FMCSA Hours of Service Rules

Four core limits define how driving time and on-duty hours are managed under the federal HOS regulations. Full detail on each is available in FMCSA's Summary of Hours of Service Regulations.

The 11-Hour Driving Limit

A driver may drive for up to 11 hours after taking at least 10 consecutive hours off duty. Once the 11 hours of driving are used, driving stops until the next 10-hour rest is complete.

The 14-Hour Duty Window

Once a driver comes on duty, a 14-hour clock starts. Driving is not allowed after the 14th hour. On-duty time is any working time—driving, loading, fueling, inspections, paperwork. Breaks taken during the day do not stop this clock and do not push it later. This is the key difference from the 11-hour rule: the 11-hour limit counts only driving, while the 14-hour window covers the whole workday.

The 30-Minute Break Requirement

After 8 cumulative hours of driving without an interruption, a driver is required to take a break of at least 30 consecutive minutes before driving again.The break can be any non-driving status—off duty, sleeper berth, or on duty but not driving—as long as it runs 30 minutes without interruption.

The 60/70-Hour Limits

These are the weekly caps. A driver may not drive after 60 hours on duty in 7 days, or 70 hours in 8 days. Which one applies depends on the carrier's schedule. The count can be reset with a restart: 34 or more hours off duty in a row begins a fresh 7- or 8-day period.

Common FMCSA Exceptions

While Hours of Service regulations establish clear limits, they also include several exceptions that recognize different operating conditions. Each exception is allowed as long as its conditions are fully met. FMCSA outlines these in its Hours of Service exceptions guidance.

Sleeper Berth Provision

A driver may split the required 10 hours off duty into two parts: at least 7 hours in the sleeper berth, plus at least 2 more hours off duty, in or out of the berth. The two parts must total at least 10 hours. When the qualifying conditions are met, the split rest periods may pause the calculation of the 14-hour driving window as provided under the regulation §395.

Adverse Driving Conditions Exception

Under limited circumstances, drivers may extend both the 11-hour driving limit and the 14-hour duty window by up to two hours because of adverse driving conditions. The exception applies only when the conditions could not reasonably have been known before the trip began.

Short-Haul Exception

This is for drivers who stay within a 150 air-mile radius of their home base and return within 14 hours. Drivers who qualify do not need an ELD or a full logbook, under §395.1(e)(1). The carrier keeps simple time records instead. Every condition has to hold each day: go past the radius or the 14 hours, and the exception no longer applies for that day. (Air miles are straight-line miles—about 172.6 road miles, not miles driven.)

Why HOS Compliance Matters

Hours of Service compliance supports more than regulatory requirements. Consistent records and documented operating practices may contribute to smoother roadside inspections, more efficient compliance reviews, and a stronger overall safety profile.

During roadside inspections, officers may review a driver's current duty status and supporting records. Accurate documentation may help simplify that process. HOS information also contributes to FMCSA's Compliance, Safety, Accountability (CSA) program, where inspection and violation data factor into safety performance measurement. Over time, consistent compliance may support operational reliability by reducing recordkeeping issues and helping identify potential problems before they become recurring compliance concerns.

Looking Ahead: How Compliance Is Documented

Understanding the rules is only one part of compliance. Equally important is maintaining accurate records of how those rules are followed. For most carriers today, that recordkeeping is supported by Electronic Logging Devices (ELDs).

Conclusion

Hours of Service compliance is one part of a broader approach to fatigue management. For additional context on how fatigue affects safety behind the wheel, see Dangers of Fatigued Driving: Tips to Stay Awake Behind the Wheel. 

Together, these regulations establish a consistent federal framework for managing driving time and required rest. Exceptions are an important part of regulatory compliance and day-to-day fleet operations. 

The next article explores how Electronic Logging Devices (ELDs) support HOS compliance through accurate recordkeeping. Hours of Service is one part of a wider federal framework; Broader overview is available in Understanding FMCSA Regulations for Trucking Companies.