The Definition of Hours of Service (HOS)

Definition of Hours of Service (HOS)

Hours of Service (HOS) are the federal rules that set the maximum time a commercial motor vehicle driver may drive and work, and the minimum time the driver must rest.

The Federal Motor Carrier Safety Administration (FMCSA) issues the HOS rules in 49 CFR Part 395. Their purpose is to prevent crashes caused by tired drivers. Fatigue slows reaction time, narrows attention and can lead to drivers falling asleep at the wheel. By limiting long stretches of driving and requiring regular rest, the rules aim to keep drivers alert.

HOS rules apply to drivers of commercial motor vehicles in interstate commerce, including long-haul and regional trucking, delivery, construction and oilfield fleets, and motorcoach and bus operations. Different limits apply to property-carrying and passenger-carrying drivers. Many companies also use HOS as one part of a broader fatigue risk management system.

How Hours of Service Works

Property-Carrying Drivers

• 11-hour driving limit: A driver may drive up to 11 hours after 10 consecutive hours off duty.
• 14-hour window: A driver may not drive beyond the 14th consecutive hour after coming on duty. Off-duty time does not extend this window, except under the sleeper berth provision.
• 30-minute break: A driver must take a 30-minute break after 8 cumulative hours of driving. On-duty not driving time, off-duty time or sleeper berth time can satisfy the break.
• 60/70-hour limit: A driver may not drive after 60 hours on duty in 7 consecutive days, or 70 hours in 8 consecutive days, depending on the carrier's schedule.
• 34-hour restart: A driver may restart the 7 or 8 day period by taking 34 or more consecutive hours off duty.

Passenger-Carrying Drivers

• 10-hour driving limit: A driver may drive up to 10 hours after 8 consecutive hours off duty.
• 15-hour on-duty limit: A driver may not drive after 15 hours on duty.
• 60/70-hour limit: The same 60 hours in 7 days or 70 hours in 8 days limit applies.

Common Provisions and Exceptions

• Sleeper berth split: Property-carrying drivers may split the 10-hour off-duty period into at least 7 hours in the sleeper berth plus at least 2 hours off duty or in the berth, totaling at least 10 hours. Neither qualifying period counts against the 14-hour window.
• Adverse driving conditions: When unexpected conditions such as snow, fog or a road closure arise, the 11-hour and 14-hour limits may be extended by up to 2 hours.
• Short-haul exception: Drivers who stay within a 150 air-mile radius and finish within a 14-hour duty day may not need records of duty status or an ELD, if they meet all conditions of the exception.

Recordkeeping

• Electronic logging devices: Most drivers who must keep records of duty status use an ELD under 49 CFR Part 395 Subpart B. The device records driving time automatically from the vehicle engine.
• Duty statuses: Drivers log time as off duty, sleeper berth, driving, or on duty not driving.

Regulations and Standards

FMCSA 49 CFR Part 395

Part 395 contains the HOS limits, the exceptions, and the rules for records of duty status. Subpart B sets the technical and use requirements for ELDs. Carriers must not allow or require a driver to drive in violation of the limits, and drivers must not drive when they are over their hours. Violations can lead to out-of-service orders at roadside, fines and a lower safety rating for the carrier.

FMCSA HOS Pilot Programs (2025 to 2026)

In September 2025, FMCSA launched two pilot programs to test more flexible rules. The Split Duty Period pilot lets enrolled drivers pause the 14-hour window for up to 3 hours. The Flexible Sleeper Berth pilot tests 6/4 and 5/5 splits of the sleeper berth period. Pre-tests ran in 2026, and in August 2026 FMCSA said it was preparing a broader rollout in 2027. The rules for drivers not enrolled in a pilot are unchanged.

Company Policy

HOS limits are a legal ceiling, not a guarantee of alertness. A driver can be within the rules and still be too tired to drive safely. Many companies set their own policies on shift work fatigue, night driving and fitness for duty that go beyond Part 395.

Good Practices for Hours of Service

• Plan trips around the rules: Build routes and schedules that fit within driving and duty limits, with time for traffic, loading delays and weather. Journey management helps set realistic plans.
• Monitor logs in real time: Use ELD and vehicle telematics data to see when drivers are close to their limits and adjust dispatch before a violation happens.
• Never pressure drivers: Make it clear that no load is worth driving over hours or driving while tired. Protect drivers who stop to rest.
• Train on the details: Teach drivers and dispatchers how the 14-hour window, the 30-minute break and the sleeper berth split work in practice.
• Audit records regularly: Review logs for edits, unassigned driving time and patterns of drivers running close to limits.
• Address fatigue beyond HOS: Encourage good sleep habits, screen for sleep disorders and allow drivers to stop when drowsy. Tools such as the SafetyIQ fatigue management platform can help track fatigue risk alongside work hours.

Example of Hours of Service (HOS)

A regional building supply distributor found that several drivers were reaching the end of their 14-hour window before finishing their last delivery. Customer delays at job sites were eating into the day. One driver drifted onto the rumble strip late in a shift and reported it to his supervisor. A log review showed he had been on duty for more than 13 hours.

The company reviewed its vehicle safety program and changed how it scheduled routes. Dispatchers began using ELD data to flag drivers with less than 2 hours left in their window. Routes were shortened, the last stop of the day was reserved for nearby customers, and drivers were told to call in rather than push to finish. The company also added fatigue awareness training. HOS violations dropped, and drivers reported feeling less rushed.

Frequently Asked Questions: Hours of Service (HOS)

What is the 14-hour rule for truck drivers?

A property-carrying driver may not drive beyond the 14th consecutive hour after coming on duty. Breaks and off-duty time during the day do not extend the window, except for qualifying sleeper berth periods. After 14 hours, the driver must take 10 consecutive hours off before driving again.

When is a 30-minute break required?

Property-carrying drivers must take a 30-minute break after 8 cumulative hours of driving. The break can be off duty, in the sleeper berth, or on duty not driving, such as fueling or loading.

How does the 34-hour restart work?

A driver who takes at least 34 consecutive hours off duty can reset the 60-hour or 70-hour weekly limit to zero. This lets the driver start a new 7 or 8 day period with full available hours.

Did FMCSA change the Hours of Service rules in 2026?

No. The standard HOS rules are unchanged for drivers not enrolled in a pilot. FMCSA is testing a Split Duty Period pilot and a Flexible Sleeper Berth pilot that began in September 2025, and said in August 2026 that it was preparing a broader rollout in 2027.