Commercial truck drivers often spend long hours behind the wheel, but federal regulations limit how long many drivers can operate a commercial vehicle without adequate rest. These truck driver hours of service rules, commonly known as HOS rules, are designed to reduce driver fatigue and help keep commercial drivers alert on the road.
According to the Federal Motor Carrier Safety Administration (FMCSA), hours of service regulations establish maximum driving and on-duty periods, along with required rest periods for covered commercial motor vehicle drivers.
When a truck driver or trucking company fails to follow applicable HOS requirements, driver fatigue and regulatory compliance may become important issues following a serious truck accident. Understanding these rules can therefore be especially important for people injured in commercial truck crashes in Phoenix and throughout Arizona.
What Are Hours of Service Rules for Truck Drivers?
Hours of service regulations are federal rules governing how long covered commercial motor vehicle drivers may drive and remain on duty before they must rest.
The regulations are primarily contained in 49 CFR Part 395 and administered by the FMCSA, which is part of the U.S. Department of Transportation.
According to the FMCSA Hours of Service regulations, HOS rules specify maximum on-duty and driving periods as well as required rest periods to help ensure drivers remain awake and alert.
Because requirements can vary depending on the type of commercial operation, the limits discussed below primarily concern property-carrying commercial motor vehicle drivers, including many semi-truck and tractor-trailer drivers.
How Many Hours Can a Truck Driver Drive?
Under federal HOS regulations, a property-carrying commercial driver generally may drive for a maximum of 11 hours after 10 consecutive hours off duty.
However, the 11-hour limit is only part of the equation.
Drivers must also comply with the 14-hour driving window. A property-carrying driver generally cannot drive beyond the 14th consecutive hour after coming on duty following 10 consecutive hours off duty.
For example, if a qualifying truck driver begins the workday at 6:00 a.m., the driver generally cannot continue driving after 8:00 p.m., even if the driver did not spend the entire 14 hours actually driving.
Importantly, ordinary off-duty periods generally do not extend the 14-hour period.
The FMCSA Summary of Hours of Service Regulations provides the current federal limits for property-carrying and passenger-carrying drivers.
What Is the 30-Minute Break Rule for Truck Drivers?
Property-carrying commercial drivers generally must take a 30-minute break after eight cumulative hours of driving if they have not already had at least a 30-minute interruption in driving.
The break may be satisfied by a consecutive 30-minute period of:
- Off-duty time
- Sleeper-berth time
- On-duty time when the driver is not driving
- A qualifying combination of these non-driving statuses
This is an important distinction. The federal rule focuses on eight cumulative hours of driving time, rather than simply requiring every driver to stop eight hours after beginning a shift.
What Is the 60/70-Hour Rule for Truck Drivers?
Federal regulations also limit the total number of hours a driver may remain on duty over multiple days.
A property-carrying driver generally may not drive after accumulating:
60 hours on duty during seven consecutive days, or
70 hours on duty during eight consecutive days.
Which limit applies depends on the motor carrier’s operations.
These restrictions address cumulative fatigue that can develop after several consecutive days of working and driving.
What Is the 34-Hour Restart Rule?
A qualifying property-carrying driver may restart the seven- or eight-day calculation after taking at least 34 consecutive hours off duty.
This allows a driver to reset the applicable 60/70-hour calculation after completing the required period away from work.
The FMCSA Hours of Service Summary provides additional information about the 60/70-hour limit and 34-hour restart.
Can Truck Drivers Split Their Required Rest Period?
Yes, when the requirements of the federal sleeper berth provision are satisfied.
Property-carrying drivers can split the required 10-hour off-duty period into two qualifying periods.
One period must include at least seven consecutive hours in the sleeper berth, while the other period must include at least two consecutive hours either inside or outside the sleeper berth.
The two periods must total at least 10 hours.
When the periods are properly paired under the federal requirements, neither qualifying period counts against the driver’s 14-hour driving window.
Drivers and motor carriers can find additional guidance in the FMCSA Interstate Truck Driver’s Guide to Hours of Service.

Are There Exceptions to Truck Driver HOS Rules?
Yes. Federal regulations contain exceptions and special provisions that can affect how HOS requirements apply to individual drivers.
This is one reason an alleged HOS violation should be evaluated based on the driver’s actual operation and circumstances.
Adverse Driving Conditions
Under qualifying adverse driving conditions, property-carrying drivers may extend the normal 11-hour driving limit and 14-hour driving window by up to two hours.
The exception does not simply allow drivers to work longer whenever they encounter ordinary traffic or fall behind schedule. The circumstances must satisfy the applicable federal requirements.
Short-Haul Exception
Some commercial drivers may also qualify for the federal short-haul exception.
Under current FMCSA rules, qualifying drivers may operate within a 150 air-mile radius of their normal work reporting location and must not exceed a 14-hour duty period, along with satisfying the other requirements of the exception.
Additional details about these exceptions are available from the FMCSA Hours of Service Final Rule.
Why Are HOS Rules Important After an Arizona Truck Accident?
Fatigue can significantly interfere with a person’s ability to drive safely.
The National Highway Traffic Safety Administration’s Drowsy Driving resource explains that fatigue can impair cognition and driving performance.
Severe sleep deprivation can also result in brief periods of unconsciousness sometimes referred to as microsleeps. NHTSA explains that a four- or five-second microsleep while traveling at 55 mph can result in a vehicle traveling more than 100 yards while the driver is effectively asleep.
For someone operating a large commercial truck, even a few seconds without proper attention can have serious consequences.
Fatigue-related truck accidents may involve:
- Delayed braking
- Failure to notice slowing or stopped traffic
- Lane departures
- Running traffic signals
- Unsafe lane changes
- Rear-end collisions
- Drifting onto roadway shoulders
- Loss of vehicle control
After a serious commercial truck accident, determining how long the truck driver had been working and driving may therefore become an important part of the investigation.
Can an HOS Violation Be Evidence in a Truck Accident Case?
Potentially.
An HOS violation does not automatically establish every element necessary to prove liability in a truck accident claim. However, evidence showing that a driver exceeded applicable driving limits, failed to take required rest periods, or maintained inaccurate records may be relevant when determining whether fatigue or regulatory noncompliance contributed to a collision.
Evidence that may be examined following a commercial truck accident can include:
- Electronic logging device (ELD) records
- Driver logs and records of duty status
- Dispatch records
- GPS and telematics information
- Fuel receipts
- Bills of lading
- Delivery schedules
- Driver communications
- Cell phone records when legally obtainable
- Dash-camera footage
- Vehicle inspection records
- Engine control module data
- Company safety policies
- Driver training records
Comparing multiple records can help investigators establish a timeline showing what the truck and driver were doing before the collision.
What Are Electronic Logging Devices?
Many commercial drivers who are required to maintain records of duty status must use an electronic logging device (ELD) unless an exception applies.
ELDs synchronize with a commercial vehicle’s engine to automatically capture certain information about vehicle movement and driving activity.
These electronic records can be important after a truck accident because they may help establish when a truck was moving, how long the driver operated it, and whether the driver’s reported duty status is consistent with other evidence.
The FMCSA provides additional information about HOS requirements and ELDs through its Motor Carrier Safety Planner.
Can a Trucking Company Be Responsible for a Fatigued Driver?
Depending on the circumstances, an investigation into a fatigue-related truck accident may extend beyond the individual driver.
The actions of the motor carrier may also need to be examined.
For example, investigators may look at:
- Dispatch schedules
- Delivery deadlines
- Driver supervision
- Safety policies
- Driver training
- HOS compliance procedures
- Electronic logging records
- Communications between dispatchers and drivers
Evidence showing that a company permitted or required unsafe driving practices could become relevant when determining responsibility for an accident.
Every commercial truck accident is different, which is why identifying all potentially responsible parties and preserving trucking records can be important.
What If the Injured Driver Was Partially at Fault?
Arizona follows a comparative negligence system.
Under Arizona Revised Statutes § 12-2505, an injured claimant’s damages can be reduced according to the claimant’s relative degree of fault that proximately caused the injury or death.
For example, a truck driver’s actions, the trucking company’s conduct, and the actions of other motorists may all need to be investigated when determining responsibility for a collision.
What Should You Do After a Fatigue-Related Truck Accident?
If you believe a fatigued commercial truck driver contributed to your accident, preserving evidence as early as possible can be important.
Commercial trucking cases can involve information that typically does not exist in an ordinary passenger-vehicle accident, including ELD data, driver logs, dispatch records, vehicle data and motor carrier documentation.
Depending on the circumstances, important steps following an accident may include obtaining medical attention, documenting the crash, preserving photographs and videos, obtaining the police report, identifying witnesses, and speaking with an attorney about preserving relevant trucking-company records.
Speak With a Phoenix Truck Accident Lawyer
If you were injured in a collision involving a semi-truck, tractor-trailer, delivery truck, or another commercial vehicle, The Law Office of Zayed Al-Sayyed can investigate the circumstances surrounding the crash, including whether driver fatigue or an hours-of-service violation may have contributed to the accident.
Our personal injury legal team can review available driving records, electronic data, trucking-company documentation, accident reports, witness statements, and other evidence to identify potentially responsible parties and help you understand your legal options.
Injured in a Phoenix Truck Accident?
When a truck driver or trucking company fails to follow federal safety regulations, the consequences can be devastating. If you were injured in a collision involving a commercial truck, The Law Office of Zayed Al-Sayyed can investigate the circumstances of your accident and help you understand your options for pursuing compensation.
Call (602) 952-9937 today to discuss your truck accident case with our Phoenix personal injury team.
Frequently Asked Questions About Truck Driver Hours of Service Rules
How many hours can a truck driver drive in one day?
A property-carrying commercial driver subject to federal HOS rules generally may drive for up to 11 hours after at least 10 consecutive hours off duty. The driver must also comply with the 14-hour driving window and other applicable HOS requirements.
Can a truck driver drive for 14 straight hours?
Generally, no. The 14-hour rule represents a driving window, not permission to drive continuously for 14 hours. A property-carrying driver generally has a maximum of 11 hours of driving time within the applicable 14-hour window.
How much rest does a truck driver need after 11 hours of driving?
Property-carrying drivers generally need 10 consecutive hours off duty before beginning another qualifying driving period, although federal regulations include provisions such as the sleeper-berth option that may apply in certain situations.
Does a lunch break stop the 14-hour clock?
Generally, an ordinary lunch or off-duty break does not extend the 14-consecutive-hour driving window. Qualifying sleeper-berth periods are treated differently under federal HOS regulations.
What happens if a truck driver violates HOS rules and causes an accident?
An HOS violation may become relevant evidence when determining whether fatigue or regulatory noncompliance contributed to an accident. Attorneys and investigators may examine ELD records, driver logs, dispatch records, GPS information, receipts and other documentation to reconstruct the driver’s activities before the collision.
Can a trucking company be liable for an HOS violation?
Depending on the facts, the conduct of both the driver and motor carrier may need to be investigated. Scheduling practices, dispatch instructions, supervision, company policies, safety procedures and HOS records can potentially become relevant when determining responsibility for a truck accident.

