Fatigue Laws for Truck Drivers
Written by Mary Salatino | Edited by Michael Purser
A fully loaded commercial truck can travel the length of a football field in just a few seconds. But what happens when the person behind the wheel is tired? Driver fatigue is one of the most underestimated hazards in commercial transportation. This is because it typically accumulates slowly over long shifts, overnight routes and demanding delivery schedules.
Federal fatigue laws exist to interrupt that cycle before it leads to disaster. These laws impose limits on daily driving hours, mandatory rest periods and electronic logging requirements to help keep drivers alert and roads safer.
So how does driver fatigue start, and what can be done to stop it? This article shows how sleepiness develops, explains how to prevent it and encourages training, awareness and defensive driving techniques to reduce exhaustion-induced accidents.
What Is Truck Driver Fatigue?
Truck driver fatigue happens when a motorist becomes physically or mentally impaired due to insufficient rest, long work hours or extended periods of concentration behind the wheel. Being tired affects both the mind and body. It slows reaction times, reduces awareness and impairs a person’s ability to make decisions. Even mild fatigue can significantly increase the risk of a serious accident when operating a large commercial vehicle.
One of the most dangerous aspects of fatigue is the possibility of micro-sleep episodes. These brief, involuntary lapses in attention can occur without warning. Although they may only last a few seconds, at highway speeds, those seconds are enough to cause crashes. Tired drivers may fail to recognize hazards, drift between lanes or brake too late to avoid a collision.
Common Causes of Truck Driver Fatigue
Truck driver weariness can result from a combination of work-related and environmental factors. One of the most common causes is simply too little sleep. Vehicle operators who are unable to maintain consistent sleep patterns may struggle to stay alert, even if they technically comply with rest requirements.
Pressure to meet unrealistic delivery schedules is another major contributor to exhaustion. Many trucking companies operate on tight timelines, which can encourage operators to push themselves to drive longer hours or skip rest entirely.
Being behind the wheel for long periods of time also puts you at risk for highway hypnosis, a dangerous sensation of losing awareness of time and surroundings. What happens when miles of open road blur together during long drives? This phenomenon can severely impact reaction time.
Certain driving conditions further increase the risk of tiredness, including nighttime driving and early morning hours when the body’s natural circadian rhythm promotes sleep.
FMCSA Hours of Service (HOS) Regulations
To combat the dangers of lethargy, the Federal Motor Carrier Safety Administration (FMCSA) implements hours of service (HOS) regulations that limit how long commercial drivers can work and drive. These federal rules ensure that individuals have adequate time to rest and recover before getting back behind the wheel.
The HOS regulations establish maximum driving hours, mandatory rest periods and limits on total on-duty time. Enforcing these requirements allows the FMCSA to reduce fatigue-related accidents and promote safer driving conditions for both truck operators and the public. Drivers should comply with these rules to increase everyone’s safety.
Driving Time Limits Under Federal Law
Under FMCSA rules, commercial personnel may drive for a maximum of 11 hours after taking the required off-duty rest period. What happens when those hours run out, but the delivery isn’t finished yet?
Once a driver begins any on-duty task, a 14-hour workday window starts. The window limits the total amount of time the person may be on duty, regardless of breaks or meal periods.
In addition to daily limits, there are also weekly cap restrictions. A commercial vehicle operator may not drive after being on duty for 60 hours in a seven-day period or 70 hours in an eight-day period, depending on the carrier’s schedule. These limits are intended to prevent burnout that builds over multiple days of work.
Required Rest and Break Periods
Federal regulations also require truckers to take mandatory breaks and rest periods to help combat lethargy. Drivers must take a 30-minute break after eight cumulative hours of driving. This break can be taken off duty or in a sleeper berth and provides an opportunity to rest and reset before continuing their trip.
Truck drivers are also required to take at least 10 consecutive hours off duty before beginning a new driving shift. This rest period allows time for adequate sleep and recovery. In some cases, operators may use a split sleeper berth option, which allows the required 10-hour off-duty period to be divided into two segments, provided one portion includes at least seven consecutive hours in the sleeper berth.
Exceptions and Special Circumstances
While hours of service rules are strictly enforced, certain limited exceptions apply in specific situations. One exception involves adverse driving conditions, such as unexpected weather or traffic issues. In these cases, truckers may extend their 11-hour driving limit and 14-hour on-duty window by up to two additional hours, provided the conditions could not have been reasonably anticipated.
These exceptions are not intended to encourage extended driving under normal circumstances; they’re in place to allow drivers to reach a safe stopping point during unpredictable circumstances. Drivers and motor carriers must still document the reason for the extension, and misuse of these exceptions can result in violations.
Electronic Logging Devices (ELDs) and Compliance
Electronic Logging Devices (ELDs) play an important role in enforcing hours of service regulations and reducing fatigue-related violations. Most commercial truckers are required to use ELDs to automatically record driving time, engine hours, vehicle movement and location data.
Key purposes of ELDs include:
- Accurately tracking driving and on-duty hours
- Reducing logbook falsification
- Ensuring compliance with FMCSA fatigue regulations
- Providing investigators with reliable data after a crash
ELDs help hold both drivers and trucking companies accountable for accuracy. In 2025, the FMCSA implemented more rigorous vetting standards for ELD manufacturers to ensure devices are secure and tamper-proof.
Fatigue and Truck Accident Statistics
Exhaustion is a well-documented factor in serious trucking accidents across the United States. According to the FMCSA, feelings of drowsiness are involved in approximately 13% of large truck crashes nationwide. While this number may appear low, these crashes are often severe due to the size and weight of commercial vehicles.
These accidents are especially dangerous because:
- Slowed reaction times reduce the ability to avoid hazards.
- Impaired judgment increases risky driving behavior.
- Drowsy drivers may fail to recognize traffic signals or stopped vehicles.
When a tired truck driver causes a crash, the resulting injuries are more likely to be catastrophic, disproportionately affecting occupants of smaller passenger vehicles.
How Investigators Identify Exhaustion After a Crash
Determining whether exhaustion played a role in a truck accident is complex. Investigators look for a combination of physical evidence, behavior and documentation to assess whether the person was too tired to operate the vehicle safely.
Common indicators of tiredness behind the wheel include:
- Late or absent braking before impact
- Drifting between lanes or running off the roadway
- Inconsistent or excessive driving hours shown in ELD data
- Delivery schedules that allow little time for rest
Investigators may also review logs, ELD records, dispatch communications and company policies. Because exhaustion is not always immediately visible, proving it requires careful analysis of both the driver’s actions and the trucking company’s practices leading up to the crash.
Take the Next Step Toward Safer Driving
Truck driver fatigue puts everyone on the road at risk. Luckily, it can be prevented.
SafeMotorist offers commercial driving and defensive driving courses designed to help transportation professionals manage long hours, stay alert and remain compliant with federal hours-of-service regulations.
Ready to make a difference? Learn more about SafeMotorist’s courses today and take an active role in making the road safer for everyone.