The complete guide to Hours of Service

What are Hours of Service (HOS)?

Hours of Service (HOS) is a way for the Federal Motor Carrier Safety Administration (FMCSA) to improve driver safety by monitoring working hours of commercial motor vehicle (CMV) operators 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 intrastate commerce or 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 work before taking a mandatory rest break.

Under the ELD mandate, operators of commercial motor vehicles are required to use electronic logging devices to track 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 and replace paper logs. 

HOS regulations were most recently amended in 2020, when the FMCSA issued its long-anticipated Final Rule on HOS. The Final Rule introduced four key changes to increase flexibility for drivers without compromising safety. Important to note: Any driver or carrier found 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.

Who is subject to Hours of Service rules?

The Hours of Service regulation applies to any CMV 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 10,001 lbs or more, including cargo

• Transports hazardous materials in a quantity requiring a hazardous material placard

• Transports 16 or more passengers, including the driver, without compensation

• Transports nine or more passengers, including the driver, for compensation

What are the driving limits for CMV drivers?

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

14-hour limit

In a single day, drivers can work a 14-hour period with a driving maximum of 11 hours. They are required to take a 30-minute break after eight hours of driving time. Drivers can satisfy the 30-minute break requirement with off-duty, sleeper berth, and/or other non-driving work. Once a driver hits their on-duty limit, they must go off duty for at least 10 hours.

11-hour driving limit

A driver is limited to a maximum of 11 hours of driving in a 14-hour shift period.

60/70-hour limit

The HOS rules cap on-duty time to 60 hours per seven day period and 70 hours in an eight day period. This means drivers cannot drive once they've reached 60 or 70 cumulative hours of on-duty time in a seven or eight consecutive-day period, respectively.

34-hour restart

The 34-hour restart rule gives 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 and must include two consecutive days off duty between 1:00 am and 5:00 am.

Rest breaks

Drivers are required to take a 30-minute rest break after continuously driving for eight 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.

Sleeper berth provision

The sleeper berth provision allows truck drivers to split their required 10-hour off-duty period into two segments, using a sleeper berth in their truck. Drivers that use the split sleeper berth provision 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. Here's a simple breakdown of the 8/2 and 7/3 split:

• 8/2 split: Drivers can take eight hours in the sleeper berth (consecutive and uninterrupted) plus two hours off-duty (can be in the sleeper berth, off-duty, or a combination).

• 7/3 split: Drivers can take seven hours in the sleeper berth (consecutive and uninterrupted) plus 3 hours off-duty (can be in the sleeper berth, off-duty, or a combination).

Both splits reset the 14-hour window from the end of the longer rest period. The shorter period (two or three hours) counts as off-duty time but does not reset the 14-hour clock on its own. The driving hours before and after the split must still comply with the 11-hour driving limit and overall HOS regulations.

What are the exemptions to driving limits?

HOS regulations are strictly enforced by the Department of Transportation (DOT), but there are certain ELD exemptions under CFR 395.

150 air-mile exemption

The 150 air-mile rule exempts property-carrying drivers from completing a daily log and having supporting documents if they remain 150 air miles from their home terminal. To meet this exemption, drivers must:

• Operate CMVs requiring a CDL

• Operate within a 150 air-mile radius of their home terminal

• 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 exception

Similarly, the 150 air-mile, non-CDL short-haul exception also exempts drivers from completing a daily log. It applies to non-CDL short-haul drivers who:

• Do not drive any vehicle that requires a CDL

• Operate within a 150 air-mile radius of their normal work reporting location

• Return to their home terminal and end their day within 14 consecutive hours

Adverse driving conditions exemption

The adverse driving condition exception allows drivers to extend their daily total number of hours worked by two hours—for a maximum of 16 hours on duty—when unexpected hazardous conditions are encountered. Drivers using the adverse driving condition exception have the flexibility to safely wait out dangerous driving conditions—such as hail or fog—or drive at a slower speed to avoid any incidents.

How to avoid HOS penalties

The best way to prevent HOS violations is to use an intuitive, reliable ELD compliance solution. Samsara's ELD solution is an FMCSA-registered ELD that automatically collects vehicle data throughout the day. Combined with the HOS log in the Samsara Driver App, it 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 drivers’ hours of service.

Through the Samsara dashboard, compliance managers can review the HOS report to see drivers' record of duty status, the amount of time until their next rest break, and the number of hours left in their driving window. This report will also automatically flag any driver approaching an HOS violation.

To learn more about how Samsara can help you remain compliant, explore our ELD compliance solution and get in touch with our team today.