The Complete Guide to Hours of Service

What are Hours of Service (HOS)?

The Hours of Service final rule was published in the Federal Register on December 2011 as a way for the Federal Motor Carrier Safety Administration (FMCSA) to monitor working hours of anyone operating a commercial motor vehicle (CMV) with a commercial driver's license (CDL) in the United States. A CMV refers to any vehicle that is used as part of a business that operates in interstate commerce. Designed to eliminate accidents caused by driver fatigue, the ruling determines the maximum number of consecutive hours a commercial truck driver or other types of CMV operators can drive or work before taking a mandatory rest break.

Under the ELD mandate, a US regulation that went into effect in December 2017, operators of commercial motor vehicles are required to use electronic logging devices to track Hours of Service (HOS). Electronic logging devices, also known as electronic logbooks or e-logs, connect to a vehicle's engine and automatically record driving time, providing a reliable way to collect HOS data. They replace paper logs which were historically used in the trucking industry to record Hours of Service.

HOS regulations were further amended in 2020, when the FMCSA issued its long-anticipated Final Rule on HOS. The Final Rule introduced four key changes to HOS regulations with the goal of increasing flexibility without compromising safety. The new rules went into effect on September 29, 2020 and are incorporated into this guide.

Anyone found to be in violation of the Hours of Service rules runs the risk of negatively impacting their carrier's safety rating or even being put out of service for a certain period of time.

What is the driving limit for CMV drivers?

The Hours of Service regulation limits the number of driving hours per day and the number of driving and working on-duty hours per week. Driving limit or cycle limit restrictions include:

14-hour shift limit

Drivers have a 14-hour window to drive a maximum of 11 hours and are required to take a 30-minute break after 8 hours of driving time. The 14-hour driving limit restricts drivers from driving any longer than the fourteenth consecutive hour on duty, after 10 hours off duty.

As part of the Final Rule on HOS that went into effect on September 29, 2020, a driver cannot drive for more than 8 hours before being required to take a 30-minute break, but could have been on-duty for more than 8 hours. Drivers can satisfy the 30-minute break requirement with off-duty, sleeper berth, and/or on-duty not driving time.

11-hour driving limit

A driver is limited to a maximum of 11 hours of driving after 10 consecutive hours off duty.

60/70-hour limit

The HOS rules cap driving time to 60 hours per 7-day period and a 70-hour time limit for a span of 8 days. This means drivers cannot continue to drive once they've reached 60/70 hours of on-duty time in 7/8 consecutive days.

34-hour restart

The 34-hour restart rule gives commercial motor vehicle drivers the opportunity to reset their 60-hour or 70-hour clocks back to zero. Drivers can take advantage of the rule at any time by taking at least 34 consecutive hours off duty or in a sleeper berth.

Rest breaks

Drivers are required to take a 30-minute rest break after continuously driving for 8 hours. Rest breaks can be logged as either off-duty time or can be taken as time in the sleeper berth at a truck stop or other rest area.

Split sleeper berth rule

A sleeper berth refers to a cab in the back of a truck that includes a reclining seat or bed that drivers can use for rest while they're on the road. Drivers can use the time spent in the sleeper berth to count towards their mandatory rest-limits or their off-duty time.

Drivers choosing to use split sleeper berth must take at least seven or eight hours in the sleeper berth and may split the sleeper berth time into two periods in either an 8/2 or 7/3 split:

• 8/2 split: For an 8/2 split, one off-duty period must be between two and eight hours (2/8 hour period) and can be spent in the sleeper berth, off-duty, or personal conveyance (or a combination of the three). The other off-duty period must be between eight and 10 hours (8/10 hour period) and can only be taken in the sleeper berth.

• 7/3 split: As part of the Final Rule on HOS that went into effect on September 29, 2020, drivers can now split their required 10 hours off-duty in a 7/3 split if they prefer, offering additional flexibility.

• The two breaks can be taken in any order and by completing both rest periods, the 14-hour driving window is re-started from the end of the first sleeper berth period but not until after the second period is completed.

• Since the 14-hour driving window does not restart after the end of the second off-duty period, the split sleeper berth is not a full 10-hour reset; it simply moves the start time of the 14-hour driving window.

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Who is subject to Hours of Service rules?

The Hours of Service regulation applies to any commercial motor vehicle operator in the United States. A commercial motor vehicle, outside of belonging to a company or corporation, is defined as any vehicle that satisfies one of the following conditions:

• Weighs (including any load) 10,001 lbs or more

• Transports hazardous materials (property-carrying vehicle) in a quantity requiring a hazardous material placard

• Transports 16 or more passengers (passenger-carrying vehicle), including the driver, without compensation

• Transports 9 or more passengers (passenger-carrying vehicle), including the driver, for compensation

How to avoid Hours of Service penalties

HOS regulations are strictly enforced by the Department of Transportation (DOT), but there are a number of ways to satisfy the ruling's requirements and even certain ELD exemptions.

150 air-mile exemption

The 150 air-mile rule exempts property-carrying CDL drivers from completing a daily log and having supporting documents within 150 air miles of their daily starting location. To meet this exemption, drivers must:

• Operate within a 150 air-mile radius of their daily starting location

• Start and end the day at the same location

• End the workday within 14 hours

• Have at least 10 hours off-duty between each 14-hour shift

150 air-mile non-CDL short-haul exemption

There is another 150 air-mile exemption that is slightly different from the 150 air-mile rule described above. This exemption is for drivers who operate a property-carrying commercial vehicle but do not require a CDL. It applies to non-CDL drivers who:

• Operate within a 150 air-mile radius of their work’s primary location

• Return to that primary work location at the end of each duty shift

Additionally, they must not:

• Drive any vehicle that requires a CDL

• Drive after 14 hours of coming on duty on 5 days of any period of 7 consecutive days

• Drive after 16 hours of coming on duty on 2 days of any period of 7 consecutive days

Adverse driving conditions exemption

The adverse driving condition exception allows drivers to extend the maximum “driving window” by up to 2 hours. For example, drivers with a maximum driving window of 14 hours can use the adverse driving condition exception to complete their drive time in a 16 hour driving window.

Before the Final Rule on HOS was enacted in September 2020, drivers could use this exemption to drive up to 2 hours beyond their maximum drive time but could not extend their maximum driving window. Now, with the ability to extend the maximum driving window by up to 2 hours, drivers using the adverse driving condition exception have the flexibility to safely wait out adverse driving conditions or drive at a slower speed to avoid any incidents.

Electronic logging device (ELD) solutions

The best way to prevent Hours of Service violations is to use an intuitive, reliable ELD compliance solution.

Samsara's electronic logging device is an FMCSA-registered ELD that connects to the engine's OBD port and automatically collects vehicle data throughout the day. This, combined with the HOS electronic log book in the Samsara Driver App, provides fleets with an accurate and complete read of their compliance. Whether you're an owner-operator or a fleet manager, Samsara can help your business gain visibility into your driver's hours of service.

Through the Samsara dashboard, compliance managers can review the Hours of Service report to see drivers' real-time driving status, the amount of time until their rest break, and the number of hours left in their driving period. This report will automatically flag any driver approaching an Hours of Service violation.

To keep your fleet compliant and avoid ELD violations, it's important to stay up to date on current ELD news and announcements. To help, we've compiled the latest news to keep you informed on the most recent ELD insights and ELD exemptions Congress has requested since the mandate launched.

Learn more about Samsara's compliance solution.